ffplay.c

/*
 * Copyright (c) 2003 Fabrice Bellard
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * simple media player based on the FFmpeg libraries
 */
#include "config.h"
#include <inttypes.h>
#include <math.h>
#include <limits.h>
#include <signal.h>
#include <stdint.h>

#include "libavutil/avstring.h"
#include "libavutil/eval.h"
#include "libavutil/mathematics.h"
#include "libavutil/pixdesc.h"
#include "libavutil/imgutils.h"
#include "libavutil/dict.h"
#include "libavutil/parseutils.h"
#include "libavutil/samplefmt.h"
#include "libavutil/avassert.h"
#include "libavutil/time.h"
#include "libavformat/avformat.h"
#include "libavdevice/avdevice.h"
#include "libswscale/swscale.h"
#include "libavutil/opt.h"
#include "libavcodec/avfft.h"
#include "libswresample/swresample.h"

#if CONFIG_AVFILTER
# include "libavfilter/avfilter.h"
# include "libavfilter/buffersink.h"
# include "libavfilter/buffersrc.h"
#endif

#include <SDL.h>
#include <SDL_thread.h>
#include "cmdutils.h"
#include <assert.h>

int ver_major = 1;
int ver_minor = 3;

const char program_name[] = "VCmpTool"; 
const int program_birth_year = 2003;

#define MAX_QUEUE_SIZE (15 * 1024 * 1024)
#define MIN_FRAMES 25
#define EXTERNAL_CLOCK_MIN_FRAMES 2
#define EXTERNAL_CLOCK_MAX_FRAMES 10

/* Minimum SDL audio buffer size, in samples. */
#define SDL_AUDIO_MIN_BUFFER_SIZE 512
/* Calculate actual buffer size keeping in mind not cause too frequent audio callbacks */
#define SDL_AUDIO_MAX_CALLBACKS_PER_SEC 30

/* Step size for volume control */
#define SDL_VOLUME_STEP (SDL_MIX_MAXVOLUME / 50)

/* no AV sync correction is done if below the minimum AV sync threshold */
#define AV_SYNC_THRESHOLD_MIN 0.04
/* AV sync correction is done if above the maximum AV sync threshold */
#define AV_SYNC_THRESHOLD_MAX 0.1
/* If a frame duration is longer than this, it will not be duplicated to compensate AV sync */
#define AV_SYNC_FRAMEDUP_THRESHOLD 0.1
/* no AV correction is done if too big error */
#define AV_NOSYNC_THRESHOLD 10.0

/* maximum audio speed change to get correct sync */
#define SAMPLE_CORRECTION_PERCENT_MAX 10

/* external clock speed adjustment constants for realtime sources based on buffer fullness */
#define EXTERNAL_CLOCK_SPEED_MIN  0.900
#define EXTERNAL_CLOCK_SPEED_MAX  1.010
#define EXTERNAL_CLOCK_SPEED_STEP 0.001

/* we use about AUDIO_DIFF_AVG_NB A-V differences to make the average */
#define AUDIO_DIFF_AVG_NB   20

/* polls for possible required screen refresh at least this often, should be less than 1/fps */
#define REFRESH_RATE 0.01

/* NOTE: the size must be big enough to compensate the hardware audio buffersize size */
/* TODO: We assume that a decoded and resampled frame fits into this buffer */
#define SAMPLE_ARRAY_SIZE (8 * 65536)

#define CURSOR_HIDE_DELAY 1000000

static unsigned sws_flags = SWS_BICUBIC;

typedef struct MyAVPacketList {
    AVPacket pkt;
    struct MyAVPacketList *next;
    int serial;
} MyAVPacketList;

typedef struct PacketQueue {
    MyAVPacketList *first_pkt, *last_pkt;
    int nb_packets;
    int size;
    int64_t duration;
    int abort_request;
    int serial;
    SDL_mutex *mutex;
    SDL_cond *cond;
} PacketQueue;

#define VIDEO_PICTURE_QUEUE_SIZE 3
#define SUBPICTURE_QUEUE_SIZE 16
#define SAMPLE_QUEUE_SIZE 9
#define FRAME_QUEUE_SIZE FFMAX(SAMPLE_QUEUE_SIZE, FFMAX(VIDEO_PICTURE_QUEUE_SIZE, SUBPICTURE_QUEUE_SIZE))

typedef struct AudioParams {
    int freq;
    int channels;
    int64_t channel_layout;
    enum AVSampleFormat fmt;
    int frame_size;
    int bytes_per_sec;
} AudioParams;
 
typedef struct Clock {
    double pts;           /* clock base */
    double pts_drift;     /* clock base minus time at which we updated the clock */
    double last_updated;
    double speed;
    int serial;           /* clock is based on a packet with this serial */
    int paused;
    int *queue_serial;    /* pointer to the current packet queue serial, used for obsolete clock detection */
} Clock;

/* Common struct for handling all types of decoded data and allocated render buffers. */
typedef struct Frame {
    AVFrame *frame;
    AVSubtitle sub;
    AVSubtitleRect **subrects;  /* rescaled subtitle rectangles in yuva */
    int serial;
    double pts;           /* presentation timestamp for the frame */
    double duration;      /* estimated duration of the frame */
    long long dec_frame_num;
    int64_t pos;          /* byte position of the frame in the input file */
    int64_t cnt;
    SDL_Overlay *bmp;
    int allocated;
    int reallocate;
    int width;
    int height;
    AVRational sar;
} Frame;

typedef struct FrameQueue {
    Frame queue[FRAME_QUEUE_SIZE];
    int rindex;
    int windex;
    int size;
    int max_size;
    int keep_last;
    int rindex_shown;
    SDL_mutex *mutex;
    SDL_cond *cond;
    PacketQueue *pktq;
} FrameQueue;

enum {
    AV_SYNC_AUDIO_MASTER, /* default choice */
    AV_SYNC_VIDEO_MASTER,
    AV_SYNC_EXTERNAL_CLOCK, /* synchronize to an external clock */
};

typedef struct Decoder {
    AVPacket pkt;
    AVPacket pkt_temp;
    PacketQueue *queue;
    AVCodecContext *avctx;
    int pkt_serial;
    int finished;
    int packet_pending;
    SDL_cond *empty_queue_cond;
    int64_t start_pts;
    AVRational start_pts_tb;
    int64_t next_pts;
    AVRational next_pts_tb;
    SDL_Thread *decoder_tid;
} Decoder;

typedef struct VideoState {
    SDL_Thread *read_tid;
    AVInputFormat *iformat;
    int abort_request;
    int force_refresh;
    int paused;
    int last_paused;
    int queue_attachments_req;
    int seek_req;
    int seek_flags;
    int64_t seek_pos;
    int64_t seek_rel;
    int read_pause_return;
    AVFormatContext *ic;
    int realtime;

    Clock audclk;
    Clock vidclk;
    Clock extclk;

    FrameQueue pictq;
    FrameQueue subpq;
    FrameQueue sampq;
    Decoder auddec;
    Decoder viddec;
    Decoder subdec;

    int viddec_width;
    int viddec_height;
    int scaleto_width;
    int scaleto_height;

    int audio_stream;
    int av_sync_type;

    double audio_clock;
    int audio_clock_serial;
    double audio_diff_cum; /* used for AV difference average computation */
    double audio_diff_avg_coef;
    double audio_diff_threshold;
    int audio_diff_avg_count;
    AVStream *audio_st;
    PacketQueue audioq;
    int audio_hw_buf_size;
    uint8_t *audio_buf;
    uint8_t *audio_buf1;
    unsigned int audio_buf_size; /* in bytes */
    unsigned int audio_buf1_size;
    int audio_buf_index; /* in bytes */
    int audio_write_buf_size;
    int audio_volume;
    int muted;
    struct AudioParams audio_src;
#if CONFIG_AVFILTER
    struct AudioParams audio_filter_src;
#endif
    struct AudioParams audio_tgt;
    struct SwrContext *swr_ctx;
    int frame_drops_early;
    int frame_drops_late;

    enum ShowMode {
        SHOW_MODE_NONE = -1, SHOW_MODE_VIDEO = 0, SHOW_MODE_WAVES, SHOW_MODE_RDFT, SHOW_MODE_NB
    } show_mode;
    int16_t sample_array[SAMPLE_ARRAY_SIZE];
    int sample_array_index;
    int last_i_start;
    RDFTContext *rdft;
    int rdft_bits;
    FFTSample *rdft_data;
    int xpos;
    double last_vis_time;

    int subtitle_stream;
    AVStream *subtitle_st;
    PacketQueue subtitleq;

    double frame_timer;
    double frame_last_returned_time;
    double frame_last_filter_delay;
    int video_stream;
    AVStream *video_st;
    PacketQueue videoq;
    double max_frame_duration;      // maximum duration of a frame - above this, we consider the jump a timestamp discontinuity
#if !CONFIG_AVFILTER
    struct SwsContext *img_convert_ctx;
#endif
    struct SwsContext *sub_convert_ctx;
    SDL_Rect last_display_rect;
    int eof;

    char *filename;
    int width, height, xleft, ytop;
    int step;
    
    double first_pts;          // record first video pts of video stream
    int vert_split_pos;        // record vertical split line position
    int last_vert_split_pos;
    int mov_speed;             // set the move speed of the vertical split line
    int left_mouse_bt_stat;    // stat of left mouse button: 0 - left mouse button up; 1 - left mouse button down
    int delay_frame_num;       // delay frame from start

    uint8_t *bk_data[4];
    int      linesize[4];

#if CONFIG_AVFILTER
    int vfilter_idx;
    AVFilterContext *in_video_filter;   // the first filter in the video chain
    AVFilterContext *out_video_filter;  // the last filter in the video chain
    AVFilterContext *in_audio_filter;   // the first filter in the audio chain
    AVFilterContext *out_audio_filter;  // the last filter in the audio chain
    AVFilterGraph *agraph;              // audio filter graph
#endif

    int last_video_stream, last_audio_stream, last_subtitle_stream;

    SDL_cond *continue_read_thread;
} VideoState;

/* options specified by the user */
static AVInputFormat *file_iformat;
static const char *input_filename[2] = {NULL, NULL};
static const char *window_title;
static int fs_screen_width;
static int fs_screen_height;
static int default_width  = 640;
static int default_height = 480;
static int screen_width  = 0;
static int screen_height = 0;
static int audio_disable;
static int video_disable;
static int subtitle_disable;
static const char* wanted_stream_spec[AVMEDIA_TYPE_NB] = {0};
static int seek_by_bytes = -1;
static int display_disable;
static int show_status = 1;
static int av_sync_type = AV_SYNC_AUDIO_MASTER;
static int64_t start_time = AV_NOPTS_VALUE;
static int64_t duration = AV_NOPTS_VALUE;
static int fast = 0;
static int genpts = 0;
static int lowres = 0;
static int decoder_reorder_pts = -1;
static int autoexit;
static int exit_on_keydown;
static int exit_on_mousedown;
static int loop = 1;
static int framedrop = -1;
static int infinite_buffer = -1;
static enum ShowMode show_mode = SHOW_MODE_NONE;
static const char *audio_codec_name;
static const char *subtitle_codec_name;
static const char *video_codec_name;
double rdftspeed = 0.02;
static int64_t cursor_last_shown;
static int cursor_hidden = 0;
#if CONFIG_AVFILTER
static const char **vfilters_list = NULL;
static int nb_vfilters = 0;
static char *afilters = NULL;
#endif
static int autorotate = 1;

/* current context */
static int is_full_screen;
static int64_t audio_callback_time;

static AVPacket flush_pkt;

#define FF_ALLOC_EVENT   (SDL_USEREVENT)
#define FF_QUIT_EVENT    (SDL_USEREVENT + 2)

static SDL_Surface *screen;

#if CONFIG_AVFILTER
static int opt_add_vfilter(void *optctx, const char *opt, const char *arg)
{
    GROW_ARRAY(vfilters_list, nb_vfilters);
    vfilters_list[nb_vfilters - 1] = arg;
    return 0;
}
#endif

static inline
int cmp_audio_fmts(enum AVSampleFormat fmt1, int64_t channel_count1,
                   enum AVSampleFormat fmt2, int64_t channel_count2)
{
    /* If channel count == 1, planar and non-planar formats are the same */
    if (channel_count1 == 1 && channel_count2 == 1)
        return av_get_packed_sample_fmt(fmt1) != av_get_packed_sample_fmt(fmt2);
    else
        return channel_count1 != channel_count2 || fmt1 != fmt2;
}

static inline
int64_t get_valid_channel_layout(int64_t channel_layout, int channels)
{
    if (channel_layout && av_get_channel_layout_nb_channels(channel_layout) == channels)
        return channel_layout;
    else
        return 0;
}

static void free_picture(Frame *vp);

static int packet_queue_put_private(PacketQueue *q, AVPacket *pkt)
{
    MyAVPacketList *pkt1;

    if (q->abort_request)
       return -1;

    pkt1 = av_malloc(sizeof(MyAVPacketList));
    if (!pkt1)
        return -1;
    pkt1->pkt = *pkt;
    pkt1->next = NULL;
    if (pkt == &flush_pkt)
        q->serial++;
    pkt1->serial = q->serial;

    if (!q->last_pkt)
        q->first_pkt = pkt1;
    else
        q->last_pkt->next = pkt1;
    q->last_pkt = pkt1;
    q->nb_packets++;
    q->size += pkt1->pkt.size + sizeof(*pkt1);
    q->duration += pkt1->pkt.duration;
    /* XXX: should duplicate packet data in DV case */
    SDL_CondSignal(q->cond);
    return 0;
}

static int packet_queue_put(PacketQueue *q, AVPacket *pkt)
{
    int ret;

    SDL_LockMutex(q->mutex);
    ret = packet_queue_put_private(q, pkt);
    SDL_UnlockMutex(q->mutex);

    if (pkt != &flush_pkt && ret < 0)
        av_packet_unref(pkt);

    return ret;
}

static int packet_queue_put_nullpacket(PacketQueue *q, int stream_index)
{
    AVPacket pkt1, *pkt = &pkt1;
    av_init_packet(pkt);
    pkt->data = NULL;
    pkt->size = 0;
    pkt->stream_index = stream_index;
    return packet_queue_put(q, pkt);
}

/* packet queue handling */
static int packet_queue_init(PacketQueue *q)
{
    memset(q, 0, sizeof(PacketQueue));
    q->mutex = SDL_CreateMutex();
    if (!q->mutex) {
        av_log(NULL, AV_LOG_FATAL, "SDL_CreateMutex(): %s\n", SDL_GetError());
        return AVERROR(ENOMEM);
    }
    q->cond = SDL_CreateCond();
    if (!q->cond) {
        av_log(NULL, AV_LOG_FATAL, "SDL_CreateCond(): %s\n", SDL_GetError());
        return AVERROR(ENOMEM);
    }
    q->abort_request = 1;
    return 0;
}

static void packet_queue_flush(PacketQueue *q)
{
    MyAVPacketList *pkt, *pkt1;

    SDL_LockMutex(q->mutex);
    for (pkt = q->first_pkt; pkt; pkt = pkt1) {
        pkt1 = pkt->next;
        av_packet_unref(&pkt->pkt);
        av_freep(&pkt);
    }
    q->last_pkt = NULL;
    q->first_pkt = NULL;
    q->nb_packets = 0;
    q->size = 0;
    q->duration = 0;
    SDL_UnlockMutex(q->mutex);
}

static void packet_queue_destroy(PacketQueue *q)
{
    packet_queue_flush(q);
    SDL_DestroyMutex(q->mutex);
    SDL_DestroyCond(q->cond);
}

static void packet_queue_abort(PacketQueue *q)
{
    SDL_LockMutex(q->mutex);

    q->abort_request = 1;

    SDL_CondSignal(q->cond);

    SDL_UnlockMutex(q->mutex);
}

static void packet_queue_start(PacketQueue *q)
{
    SDL_LockMutex(q->mutex);
    q->abort_request = 0;
    packet_queue_put_private(q, &flush_pkt);
    SDL_UnlockMutex(q->mutex);
}

/* return < 0 if aborted, 0 if no packet and > 0 if packet.  */
static int packet_queue_get(PacketQueue *q, AVPacket *pkt, int block, int *serial)
{
    MyAVPacketList *pkt1;
    int ret;

    SDL_LockMutex(q->mutex);

    for (;;) {
        if (q->abort_request) {
            ret = -1;
            break;
        }

        pkt1 = q->first_pkt;
        if (pkt1) {
            q->first_pkt = pkt1->next;
            if (!q->first_pkt)
                q->last_pkt = NULL;
            q->nb_packets--;
            q->size -= pkt1->pkt.size + sizeof(*pkt1);
            q->duration -= pkt1->pkt.duration;
            *pkt = pkt1->pkt;
            if (serial)
                *serial = pkt1->serial;
            av_free(pkt1);
            ret = 1;
            break;
        } else if (!block) {
            ret = 0;
            break;
        } else {
            SDL_CondWait(q->cond, q->mutex);
        }
    }
    SDL_UnlockMutex(q->mutex);
    return ret;
}

static void decoder_init(Decoder *d, AVCodecContext *avctx, PacketQueue *queue, SDL_cond *empty_queue_cond) {
    memset(d, 0, sizeof(Decoder));
    d->avctx = avctx;
    d->queue = queue;
    d->empty_queue_cond = empty_queue_cond;
    d->start_pts = AV_NOPTS_VALUE;
}

static int decoder_decode_frame(Decoder *d, AVFrame *frame, AVSubtitle *sub) {
    int got_frame = 0;

    do {
        int ret = -1;

        if (d->queue->abort_request)
            return -1;

        if (!d->packet_pending || d->queue->serial != d->pkt_serial) {
            AVPacket pkt;
            do {
                if (d->queue->nb_packets == 0)
                    SDL_CondSignal(d->empty_queue_cond);
                if (packet_queue_get(d->queue, &pkt, 1, &d->pkt_serial) < 0)
                    return -1;
                if (pkt.data == flush_pkt.data) {
                    avcodec_flush_buffers(d->avctx);
                    d->finished = 0;
                    d->next_pts = d->start_pts;
                    d->next_pts_tb = d->start_pts_tb;
                }
            } while (pkt.data == flush_pkt.data || d->queue->serial != d->pkt_serial);
            av_packet_unref(&d->pkt);
            d->pkt_temp = d->pkt = pkt;
            d->packet_pending = 1;
        }

        switch (d->avctx->codec_type) {
            case AVMEDIA_TYPE_VIDEO:
                ret = avcodec_decode_video2(d->avctx, frame, &got_frame, &d->pkt_temp);
                if (got_frame) {
                    if (decoder_reorder_pts == -1) {
                        frame->pts = av_frame_get_best_effort_timestamp(frame);
                    } else if (decoder_reorder_pts) {
                        frame->pts = frame->pkt_pts;
                    } else {
                        frame->pts = frame->pkt_dts;
                    }
                }
                break;
            case AVMEDIA_TYPE_AUDIO:
                ret = avcodec_decode_audio4(d->avctx, frame, &got_frame, &d->pkt_temp);
                if (got_frame) {
                    AVRational tb = (AVRational){1, frame->sample_rate};
                    if (frame->pts != AV_NOPTS_VALUE)
                        frame->pts = av_rescale_q(frame->pts, d->avctx->time_base, tb);
                    else if (frame->pkt_pts != AV_NOPTS_VALUE)
                        frame->pts = av_rescale_q(frame->pkt_pts, av_codec_get_pkt_timebase(d->avctx), tb);
                    else if (d->next_pts != AV_NOPTS_VALUE)
                        frame->pts = av_rescale_q(d->next_pts, d->next_pts_tb, tb);
                    if (frame->pts != AV_NOPTS_VALUE) {
                        d->next_pts = frame->pts + frame->nb_samples;
                        d->next_pts_tb = tb;
                    }
                }
                break;
            case AVMEDIA_TYPE_SUBTITLE:
                ret = avcodec_decode_subtitle2(d->avctx, sub, &got_frame, &d->pkt_temp);
                break;
        }

        if (ret < 0) {
            d->packet_pending = 0;
        } else {
            d->pkt_temp.dts =
            d->pkt_temp.pts = AV_NOPTS_VALUE;
            if (d->pkt_temp.data) {
                if (d->avctx->codec_type != AVMEDIA_TYPE_AUDIO)
                    ret = d->pkt_temp.size;
                d->pkt_temp.data += ret;
                d->pkt_temp.size -= ret;
                if (d->pkt_temp.size <= 0)
                    d->packet_pending = 0;
            } else {
                if (!got_frame) {
                    d->packet_pending = 0;
                    d->finished = d->pkt_serial;
                }
            }
        }
    } while (!got_frame && !d->finished);

    return got_frame;
}

static void decoder_destroy(Decoder *d) {
    av_packet_unref(&d->pkt);
    avcodec_free_context(&d->avctx);
}

static void frame_queue_unref_item(Frame *vp)
{
    int i;
    for (i = 0; i < vp->sub.num_rects; i++) {
        av_freep(&vp->subrects[i]->data[0]);
        av_freep(&vp->subrects[i]);
    }
    av_freep(&vp->subrects);
    av_frame_unref(vp->frame);
    avsubtitle_free(&vp->sub);
}

static int frame_queue_init(FrameQueue *f, PacketQueue *pktq, int max_size, int keep_last)
{
    int i;
    memset(f, 0, sizeof(FrameQueue));
    if (!(f->mutex = SDL_CreateMutex())) {
        av_log(NULL, AV_LOG_FATAL, "SDL_CreateMutex(): %s\n", SDL_GetError());
        return AVERROR(ENOMEM);
    }
    if (!(f->cond = SDL_CreateCond())) {
        av_log(NULL, AV_LOG_FATAL, "SDL_CreateCond(): %s\n", SDL_GetError());
        return AVERROR(ENOMEM);
    }
    f->pktq = pktq;
    f->max_size = FFMIN(max_size, FRAME_QUEUE_SIZE);
    f->keep_last = !!keep_last;
    for (i = 0; i < f->max_size; i++)
        if (!(f->queue[i].frame = av_frame_alloc()))
            return AVERROR(ENOMEM);
    return 0;
}

static void frame_queue_destory(FrameQueue *f)
{
    int i;
    for (i = 0; i < f->max_size; i++) {
        Frame *vp = &f->queue[i];
        frame_queue_unref_item(vp);
        av_frame_free(&vp->frame);
        free_picture(vp);
    }
    SDL_DestroyMutex(f->mutex);
    SDL_DestroyCond(f->cond);
}

static void frame_queue_signal(FrameQueue *f)
{
    SDL_LockMutex(f->mutex);
    SDL_CondSignal(f->cond);
    SDL_UnlockMutex(f->mutex);
}

static Frame *frame_queue_peek(FrameQueue *f)
{
    return &f->queue[(f->rindex + f->rindex_shown) % f->max_size];
}

static Frame *frame_queue_peek_next(FrameQueue *f)
{
    return &f->queue[(f->rindex + f->rindex_shown + 1) % f->max_size];
}

static Frame *frame_queue_peek_last(FrameQueue *f)
{
    return &f->queue[f->rindex];
}

static Frame *frame_queue_peek_writable(FrameQueue *f)
{
    /* wait until we have space to put a new frame */
    SDL_LockMutex(f->mutex);
    while (f->size >= f->max_size &&
           !f->pktq->abort_request) {
        SDL_CondWait(f->cond, f->mutex);
    }
    SDL_UnlockMutex(f->mutex);

    if (f->pktq->abort_request)
        return NULL;

    return &f->queue[f->windex];
}

static Frame *frame_queue_peek_readable(FrameQueue *f)
{
    /* wait until we have a readable a new frame */
    SDL_LockMutex(f->mutex);
    while (f->size - f->rindex_shown <= 0 &&
           !f->pktq->abort_request) {
        SDL_CondWait(f->cond, f->mutex);
    }
    SDL_UnlockMutex(f->mutex);

    if (f->pktq->abort_request)
        return NULL;

    return &f->queue[(f->rindex + f->rindex_shown) % f->max_size];
}

static void frame_queue_push(FrameQueue *f)
{
    if (++f->windex == f->max_size)
        f->windex = 0;
    SDL_LockMutex(f->mutex);
    f->size++;
    SDL_CondSignal(f->cond);
    SDL_UnlockMutex(f->mutex);
}

static void frame_queue_next(FrameQueue *f)
{
    if (f->keep_last && !f->rindex_shown) {
        f->rindex_shown = 1;
        return;
    }
    frame_queue_unref_item(&f->queue[f->rindex]);
    if (++f->rindex == f->max_size)
        f->rindex = 0;
    SDL_LockMutex(f->mutex);
    f->size--;
    SDL_CondSignal(f->cond);
    SDL_UnlockMutex(f->mutex);
}

/* return the number of undisplayed frames in the queue */
static int frame_queue_nb_remaining(FrameQueue *f)
{
    return f->size - f->rindex_shown;
}

/* return last shown position */
static int64_t frame_queue_last_pos(FrameQueue *f)
{
    Frame *fp = &f->queue[f->rindex];
    if (f->rindex_shown && fp->serial == f->pktq->serial)
        return fp->pos;
    else
        return -1;
}

static void decoder_abort(Decoder *d, FrameQueue *fq)
{
    packet_queue_abort(d->queue);
    frame_queue_signal(fq);
    SDL_WaitThread(d->decoder_tid, NULL);
    d->decoder_tid = NULL;
    packet_queue_flush(d->queue);
}

static inline void fill_rectangle(SDL_Surface *screen,
                                  int x, int y, int w, int h, int color, int update)
{
    SDL_Rect rect;
    rect.x = x;
    rect.y = y;
    rect.w = w;
    rect.h = h;
    SDL_FillRect(screen, &rect, color);
    if (update && w > 0 && h > 0)
        SDL_UpdateRect(screen, x, y, w, h);
}

/* draw only the border of a rectangle */
static void fill_border(int xleft, int ytop, int width, int height, int x, int y, int w, int h, int color, int update)
{
    int w1, w2, h1, h2;

    /* fill the background */
    w1 = x;
    if (w1 < 0)
        w1 = 0;
    w2 = width - (x + w);
    if (w2 < 0)
        w2 = 0;
    h1 = y;
    if (h1 < 0)
        h1 = 0;
    h2 = height - (y + h);
    if (h2 < 0)
        h2 = 0;
    fill_rectangle(screen,
                   xleft, ytop,
                   w1, height,
                   color, update);
    fill_rectangle(screen,
                   xleft + width - w2, ytop,
                   w2, height,
                   color, update);
    fill_rectangle(screen,
                   xleft + w1, ytop,
                   width - w1 - w2, h1,
                   color, update);
    fill_rectangle(screen,
                   xleft + w1, ytop + height - h2,
                   width - w1 - w2, h2,
                   color, update);
}

#define ALPHA_BLEND(a, oldp, newp, s)\
((((oldp << s) * (255 - (a))) + (newp * (a))) / (255 << s))



#define BPP 1

static void blend_subrect(uint8_t **data, int *linesize, const AVSubtitleRect *rect, int imgw, int imgh)
{
    int x, y, Y, U, V, A;
    uint8_t *lum, *cb, *cr;
    int dstx, dsty, dstw, dsth;
    const AVSubtitleRect *src = rect;

    dstw = av_clip(rect->w, 0, imgw);
    dsth = av_clip(rect->h, 0, imgh);
    dstx = av_clip(rect->x, 0, imgw - dstw);
    dsty = av_clip(rect->y, 0, imgh - dsth);
    lum = data[0] + dstx + dsty * linesize[0];
    cb  = data[1] + dstx/2 + (dsty >> 1) * linesize[1];
    cr  = data[2] + dstx/2 + (dsty >> 1) * linesize[2];

    for (y = 0; y<dsth; y++) {
        for (x = 0; x<dstw; x++) {
            Y = src->data[0][x + y*src->linesize[0]];
            A = src->data[3][x + y*src->linesize[3]];
            lum[0] = ALPHA_BLEND(A, lum[0], Y, 0);
            lum++;
        }
        lum += linesize[0] - dstw;
    }

    for (y = 0; y<dsth/2; y++) {
        for (x = 0; x<dstw/2; x++) {
            U = src->data[1][x + y*src->linesize[1]];
            V = src->data[2][x + y*src->linesize[2]];
            A = src->data[3][2*x     +  2*y   *src->linesize[3]]
              + src->data[3][2*x + 1 +  2*y   *src->linesize[3]]
              + src->data[3][2*x + 1 + (2*y+1)*src->linesize[3]]
              + src->data[3][2*x     + (2*y+1)*src->linesize[3]];
            cb[0] = ALPHA_BLEND(A>>2, cb[0], U, 0);
            cr[0] = ALPHA_BLEND(A>>2, cr[0], V, 0);
            cb++;
            cr++;
        }
        cb += linesize[1] - dstw/2;
        cr += linesize[2] - dstw/2;
    }
}

static void free_picture(Frame *vp)
{
     if (vp->bmp) {
         SDL_FreeYUVOverlay(vp->bmp);
         vp->bmp = NULL;
     }
}

static void calculate_display_rect(SDL_Rect *rect,
                                   int scr_xleft, int scr_ytop, int scr_width, int scr_height,
                                   int pic_width, int pic_height, AVRational pic_sar)
{
    float aspect_ratio;
    int width, height, x, y;

    if (pic_sar.num == 0)
        aspect_ratio = 0;
    else
        aspect_ratio = av_q2d(pic_sar);

    if (aspect_ratio <= 0.0)
        aspect_ratio = 1.0;
    aspect_ratio *= (float)pic_width / (float)pic_height;

    /* XXX: we suppose the screen has a 1.0 pixel ratio */
    height = scr_height;
    width = lrint(height * aspect_ratio) & ~1;
    if (width > scr_width) {
        width = scr_width;
        height = lrint(width / aspect_ratio) & ~1;
    }
    x = (scr_width - width) / 2;
    y = (scr_height - height) / 2;
    rect->x = scr_xleft + x;
    rect->y = scr_ytop  + y;
    rect->w = FFMAX(width,  1);
    rect->h = FFMAX(height, 1);
}

static void video_image_display(VideoState *is, VideoState *aux_is)
{
    Frame *vp, *aux_vp = NULL;
    Frame *sp;
    SDL_Rect rect;
    int i;

    vp = frame_queue_peek_last(&is->pictq);
    if(aux_is)
    {
        char new_title[400];
        int vns = 0, vhh = 0, vmm = 0, vss = 0, vms = 0, ans = 0, ahh = 0, amm = 0, ass = 0, ams = 0;
        aux_vp = frame_queue_peek_last(&aux_is->pictq);
        // set window title to show played time for each file
        if(!isnan(vp->pts) && !isnan(aux_vp->pts)) // raw bitstream may have no pts
        {        
            vns  = (int)vp->pts;
            vhh  = vns / 3600;
            vmm  = (vns % 3600) / 60;
            vss  = (vns % 60);
            vms  = 1000 * (vp->pts - (vhh * 3600 + vmm * 60 + vss));
            ans  = (int)aux_vp->pts;
            ahh  = ans / 3600;
            amm  = (ans % 3600) / 60;
            ass  = (ans % 60);
            ams  = 1000 * (aux_vp->pts - (ahh * 3600 + amm * 60 + ass));   
            if(input_filename[1])
                sprintf(new_title, "%s (%dx%d) %2d:%02d:%02d.%03d <------->  %s (%dx%d) %2d:%02d:%02d.%03d", 
                        is->filename, is->viddec_width,     is->viddec_height,     vhh, vmm, vss, vms, 
                        aux_is->filename, aux_is->viddec_width, aux_is->viddec_height, ahh, amm, ass, ams);
            SDL_WM_SetCaption(new_title, new_title);
        }
        else // if no pts, display frame number
        {
            if(input_filename[1])
                sprintf(new_title, "%s (%dx%d)  %lld frm <------->  %s (%dx%d) %lld frm", 
                        is->filename, is->viddec_width, is->viddec_height, vp->dec_frame_num, 
                        aux_is->filename, aux_is->viddec_width, aux_is->viddec_height, aux_vp->dec_frame_num);
            SDL_WM_SetCaption(new_title, new_title);
        }
    }
        
    if (vp->bmp) {
        if (is->subtitle_st) {
            if (frame_queue_nb_remaining(&is->subpq) > 0) {
                sp = frame_queue_peek(&is->subpq);

                if (vp->pts >= sp->pts + ((float) sp->sub.start_display_time / 1000)) {
                    uint8_t *data[4];
                    int linesize[4];

                    SDL_LockYUVOverlay (vp->bmp);

                    data[0] = vp->bmp->pixels[0];
                    data[1] = vp->bmp->pixels[2];
                    data[2] = vp->bmp->pixels[1];

                    linesize[0] = vp->bmp->pitches[0];
                    linesize[1] = vp->bmp->pitches[2];
                    linesize[2] = vp->bmp->pitches[1];

                    for (i = 0; i < sp->sub.num_rects; i++)
                        blend_subrect(data, linesize, sp->subrects[i],
                                      vp->bmp->w, vp->bmp->h);

                    SDL_UnlockYUVOverlay (vp->bmp);
                }
            }
        }
        if(aux_is)  // need to blend two frame 
        {
            if(aux_vp->bmp)
            {
                uint8_t *data[4], *aux_data[4];
                int linesize[4], aux_linesize[4];
                
                SDL_LockYUVOverlay (vp->bmp);
                SDL_LockYUVOverlay (aux_vp->bmp);
                
                if(is->paused && (is->last_vert_split_pos <= is->vert_split_pos || is->step)) // paused and move from left to right
                { // first restore original frame
                    for(i = 0; i < vp->height; i++)
                        memcpy(vp->bmp->pixels[0] + i * vp->bmp->pitches[0], is->bk_data[0] + i * vp->width, vp->width);
                    for(i = 0; i < vp->height / 2; i++)
                    {
                        memcpy(vp->bmp->pixels[1] + i * vp->bmp->pitches[1], is->bk_data[1] + i * vp->width / 2, vp->width / 2);
                        memcpy(vp->bmp->pixels[2] + i * vp->bmp->pitches[2], is->bk_data[2] + i * vp->width / 2, vp->width / 2);
                    }
                }
                data[0] = vp->bmp->pixels[0];
                data[1] = vp->bmp->pixels[2];
                data[2] = vp->bmp->pixels[1];
    
                linesize[0] = vp->bmp->pitches[0];
                linesize[1] = vp->bmp->pitches[2];
                linesize[2] = vp->bmp->pitches[1];
    
                aux_data[0] = aux_vp->bmp->pixels[0];
                aux_data[1] = aux_vp->bmp->pixels[2];
                aux_data[2] = aux_vp->bmp->pixels[1];
    
                aux_linesize[0] = aux_vp->bmp->pitches[0];
                aux_linesize[1] = aux_vp->bmp->pitches[2];
                aux_linesize[2] = aux_vp->bmp->pitches[1];
                
                for (i = 0; i < vp->height; i++)
                {
                    memcpy(data[0] + i * linesize[0] + is->vert_split_pos, aux_data[0] + i * aux_linesize[0] + is->vert_split_pos, vp->width - is->vert_split_pos);
                    *(uint16_t *)(data[0] + i * linesize[0] + (is->vert_split_pos / 2) * 2) = 255;
                    *(uint16_t *)(data[0] + i * linesize[0] + (is->vert_split_pos / 2) * 2 + 1) = 255;
                }
                for (i = 0; i < vp->height / 2; i++)
                {
                    memcpy(data[1] + i * linesize[1] + is->vert_split_pos / 2, aux_data[1] + i * aux_linesize[1] + is->vert_split_pos / 2, (vp->width - is->vert_split_pos) / 2);
                    memcpy(data[2] + i * linesize[2] + is->vert_split_pos / 2, aux_data[2] + i * aux_linesize[2] + is->vert_split_pos / 2, (vp->width - is->vert_split_pos) / 2);
                    *(data[1] + i * linesize[1] + is->vert_split_pos / 2) = 128;
                    *(data[2] + i * linesize[2] + is->vert_split_pos / 2) = 128;
                }
                
                //FILE* fp = fopen("D:\\debug.yuv", "ab");
                //fwrite(data[0], vp->width * vp->height, 1, fp);
                //fwrite(data[1], vp->width * vp->height / 4, 1, fp);
                //fwrite(data[2], vp->width * vp->height / 4, 1, fp);
                //fclose(fp);

                SDL_UnlockYUVOverlay (vp->bmp);
                SDL_UnlockYUVOverlay (aux_vp->bmp);

                if(!is->paused)
                {
                    if(is->vert_split_pos + is->mov_speed > vp->width || is->vert_split_pos + is->mov_speed < 0)
                	       is->mov_speed = -is->mov_speed;
                    is->vert_split_pos += is->mov_speed;
                }   
            }
        }

        calculate_display_rect(&rect, is->xleft, is->ytop, is->width, is->height, vp->width, vp->height, vp->sar);

        SDL_DisplayYUVOverlay(vp->bmp, &rect);

        if (rect.x != is->last_display_rect.x || rect.y != is->last_display_rect.y || rect.w != is->last_display_rect.w || rect.h != is->last_display_rect.h || is->force_refresh) {
            int bgcolor = SDL_MapRGB(screen->format, 0x00, 0x00, 0x00);
            fill_border(is->xleft, is->ytop, is->width, is->height, rect.x, rect.y, rect.w, rect.h, bgcolor, 1);
            is->last_display_rect = rect;
        }
    }
}

static inline int compute_mod(int a, int b)
{
    return a < 0 ? a%b + b : a%b;
}

static void video_audio_display(VideoState *s)
{
    int i, i_start, x, y1, y, ys, delay, n, nb_display_channels;
    int ch, channels, h, h2, bgcolor, fgcolor;
    int64_t time_diff;
    int rdft_bits, nb_freq;

    for (rdft_bits = 1; (1 << rdft_bits) < 2 * s->height; rdft_bits++)
        ;
    nb_freq = 1 << (rdft_bits - 1);

    /* compute display index : center on currently output samples */
    channels = s->audio_tgt.channels;
    nb_display_channels = channels;
    if (!s->paused) {
        int data_used= s->show_mode == SHOW_MODE_WAVES ? s->width : (2*nb_freq);
        n = 2 * channels;
        delay = s->audio_write_buf_size;
        delay /= n;

        /* to be more precise, we take into account the time spent since
           the last buffer computation */
        if (audio_callback_time) {
            time_diff = av_gettime_relative() - audio_callback_time;
            delay -= (time_diff * s->audio_tgt.freq) / 1000000;
        }

        delay += 2 * data_used;
        if (delay < data_used)
            delay = data_used;

        i_start= x = compute_mod(s->sample_array_index - delay * channels, SAMPLE_ARRAY_SIZE);
        if (s->show_mode == SHOW_MODE_WAVES) {
            h = INT_MIN;
            for (i = 0; i < 1000; i += channels) {
                int idx = (SAMPLE_ARRAY_SIZE + x - i) % SAMPLE_ARRAY_SIZE;
                int a = s->sample_array[idx];
                int b = s->sample_array[(idx + 4 * channels) % SAMPLE_ARRAY_SIZE];
                int c = s->sample_array[(idx + 5 * channels) % SAMPLE_ARRAY_SIZE];
                int d = s->sample_array[(idx + 9 * channels) % SAMPLE_ARRAY_SIZE];
                int score = a - d;
                if (h < score && (b ^ c) < 0) {
                    h = score;
                    i_start = idx;
                }
            }
        }

        s->last_i_start = i_start;
    } else {
        i_start = s->last_i_start;
    }

    bgcolor = SDL_MapRGB(screen->format, 0x00, 0x00, 0x00);
    if (s->show_mode == SHOW_MODE_WAVES) {
        fill_rectangle(screen,
                       s->xleft, s->ytop, s->width, s->height,
                       bgcolor, 0);

        fgcolor = SDL_MapRGB(screen->format, 0xff, 0xff, 0xff);

        /* total height for one channel */
        h = s->height / nb_display_channels;
        /* graph height / 2 */
        h2 = (h * 9) / 20;
        for (ch = 0; ch < nb_display_channels; ch++) {
            i = i_start + ch;
            y1 = s->ytop + ch * h + (h / 2); /* position of center line */
            for (x = 0; x < s->width; x++) {
                y = (s->sample_array[i] * h2) >> 15;
                if (y < 0) {
                    y = -y;
                    ys = y1 - y;
                } else {
                    ys = y1;
                }
                fill_rectangle(screen,
                               s->xleft + x, ys, 1, y,
                               fgcolor, 0);
                i += channels;
                if (i >= SAMPLE_ARRAY_SIZE)
                    i -= SAMPLE_ARRAY_SIZE;
            }
        }

        fgcolor = SDL_MapRGB(screen->format, 0x00, 0x00, 0xff);

        for (ch = 1; ch < nb_display_channels; ch++) {
            y = s->ytop + ch * h;
            fill_rectangle(screen,
                           s->xleft, y, s->width, 1,
                           fgcolor, 0);
        }
        SDL_UpdateRect(screen, s->xleft, s->ytop, s->width, s->height);
    } else {
        nb_display_channels= FFMIN(nb_display_channels, 2);
        if (rdft_bits != s->rdft_bits) {
            av_rdft_end(s->rdft);
            av_free(s->rdft_data);
            s->rdft = av_rdft_init(rdft_bits, DFT_R2C);
            s->rdft_bits = rdft_bits;
            s->rdft_data = av_malloc_array(nb_freq, 4 *sizeof(*s->rdft_data));
        }
        if (!s->rdft || !s->rdft_data){
            av_log(NULL, AV_LOG_ERROR, "Failed to allocate buffers for RDFT, switching to waves display\n");
            s->show_mode = SHOW_MODE_WAVES;
        } else {
            FFTSample *data[2];
            for (ch = 0; ch < nb_display_channels; ch++) {
                data[ch] = s->rdft_data + 2 * nb_freq * ch;
                i = i_start + ch;
                for (x = 0; x < 2 * nb_freq; x++) {
                    double w = (x-nb_freq) * (1.0 / nb_freq);
                    data[ch][x] = s->sample_array[i] * (1.0 - w * w);
                    i += channels;
                    if (i >= SAMPLE_ARRAY_SIZE)
                        i -= SAMPLE_ARRAY_SIZE;
                }
                av_rdft_calc(s->rdft, data[ch]);
            }
            /* Least efficient way to do this, we should of course
             * directly access it but it is more than fast enough. */
            for (y = 0; y < s->height; y++) {
                double w = 1 / sqrt(nb_freq);
                int a = sqrt(w * hypot(data[0][2 * y + 0], data[0][2 * y + 1]));
                int b = (nb_display_channels == 2 ) ? sqrt(w * hypot(data[1][2 * y + 0], data[1][2 * y + 1]))
                                                    : a;
                a = FFMIN(a, 255);
                b = FFMIN(b, 255);
                fgcolor = SDL_MapRGB(screen->format, a, b, (a + b) / 2);

                fill_rectangle(screen,
                            s->xpos, s->height-y, 1, 1,
                            fgcolor, 0);
            }
        }
        SDL_UpdateRect(screen, s->xpos, s->ytop, 1, s->height);
        if (!s->paused)
            s->xpos++;
        if (s->xpos >= s->width)
            s->xpos= s->xleft;
    }
}

static void stream_component_close(VideoState *is, int stream_index)
{
    AVFormatContext *ic = is->ic;
    AVCodecParameters *codecpar;

    if (stream_index < 0 || stream_index >= ic->nb_streams)
        return;
    codecpar = ic->streams[stream_index]->codecpar;

    switch (codecpar->codec_type) {
    case AVMEDIA_TYPE_AUDIO:
        decoder_abort(&is->auddec, &is->sampq);
        SDL_CloseAudio();
        decoder_destroy(&is->auddec);
        swr_free(&is->swr_ctx);
        av_freep(&is->audio_buf1);
        is->audio_buf1_size = 0;
        is->audio_buf = NULL;

        if (is->rdft) {
            av_rdft_end(is->rdft);
            av_freep(&is->rdft_data);
            is->rdft = NULL;
            is->rdft_bits = 0;
        }
        break;
    case AVMEDIA_TYPE_VIDEO:
        decoder_abort(&is->viddec, &is->pictq);
        decoder_destroy(&is->viddec);
        av_free(is->bk_data[0]);
        av_free(is->bk_data[1]);
        av_free(is->bk_data[2]);
        break;
    case AVMEDIA_TYPE_SUBTITLE:
        decoder_abort(&is->subdec, &is->subpq);
        decoder_destroy(&is->subdec);
        break;
    default:
        break;
    }

    ic->streams[stream_index]->discard = AVDISCARD_ALL;
    switch (codecpar->codec_type) {
    case AVMEDIA_TYPE_AUDIO:
        is->audio_st = NULL;
        is->audio_stream = -1;
        break;
    case AVMEDIA_TYPE_VIDEO:
        is->video_st = NULL;
        is->video_stream = -1;
        break;
    case AVMEDIA_TYPE_SUBTITLE:
        is->subtitle_st = NULL;
        is->subtitle_stream = -1;
        break;
    default:
        break;
    }
}

static void stream_close(VideoState *is)
{
    /* XXX: use a special url_shutdown call to abort parse cleanly */
    is->abort_request = 1;
    SDL_WaitThread(is->read_tid, NULL);

    /* close each stream */
    if (is->audio_stream >= 0)
        stream_component_close(is, is->audio_stream);
    if (is->video_stream >= 0)
        stream_component_close(is, is->video_stream);
    if (is->subtitle_stream >= 0)
        stream_component_close(is, is->subtitle_stream);

    avformat_close_input(&is->ic);

    packet_queue_destroy(&is->videoq);
    packet_queue_destroy(&is->audioq);
    packet_queue_destroy(&is->subtitleq);

    /* free all pictures */
    frame_queue_destory(&is->pictq);
    frame_queue_destory(&is->sampq);
    frame_queue_destory(&is->subpq);
    SDL_DestroyCond(is->continue_read_thread);
#if !CONFIG_AVFILTER
    sws_freeContext(is->img_convert_ctx);
#endif
    sws_freeContext(is->sub_convert_ctx);
    av_free(is->filename);
    av_free(is);
}

static void do_exit(VideoState *is)
{
    if (is) {
        stream_close(is);
    }
    av_lockmgr_register(NULL);
    uninit_opts();
#if CONFIG_AVFILTER
    av_freep(&vfilters_list);
#endif
    avformat_network_deinit();
    if (show_status)
        printf("\n");
    SDL_Quit();
    av_log(NULL, AV_LOG_QUIET, "%s", "");
    exit(0);
}

static void sigterm_handler(int sig)
{
    exit(123);
}

static void set_default_window_size(int width, int height, AVRational sar)
{
    SDL_Rect rect;
    calculate_display_rect(&rect, 0, 0, INT_MAX, height, width, height, sar);
    default_width  = rect.w;
    default_height = rect.h;
}

static int video_open(VideoState *is, int force_set_video_mode, Frame *vp)
{
    int flags = SDL_HWSURFACE | SDL_ASYNCBLIT | SDL_HWACCEL | SDL_DOUBLEBUF;
    //int flags = SDL_HWSURFACE | SDL_HWACCEL | SDL_DOUBLEBUF;
    //int flags = SDL_HWSURFACE | SDL_DOUBLEBUF;
    int w,h;
    char new_title[400];

    if (is_full_screen) flags |= SDL_FULLSCREEN;
    else                flags |= SDL_RESIZABLE;

    if (vp && vp->width)
        set_default_window_size(vp->width, vp->height, vp->sar);

    if (is_full_screen && fs_screen_width) {
        w = fs_screen_width;
        h = fs_screen_height;
    } else if (!is_full_screen && screen_width) {
        w = screen_width;
        h = screen_height;
    } else {
        w = default_width;
        h = default_height;
    }
    w = FFMIN(16383, w);
    if (screen && is->width == screen->w && screen->w == w
       && is->height== screen->h && screen->h == h && !force_set_video_mode)
        return 0;
    screen = SDL_SetVideoMode(w, h, 0, flags);
    if (!screen) {
        av_log(NULL, AV_LOG_FATAL, "SDL: could not set video mode - exiting\n");
        do_exit(is);
    }
    if (!window_title)
        window_title = input_filename[0];
    if(input_filename[1])
    {
        sprintf(new_title, "%s  <--------------->  %s", input_filename[0], input_filename[1]);
        window_title = new_title;
    }
    SDL_WM_SetCaption(window_title, window_title);

    is->width  = screen->w;
    is->height = screen->h;

    return 0;
}

/* display the current picture, if any */
static void video_display(VideoState *is, VideoState *aux_is)
{
    if (!screen)
        video_open(is, 0, NULL);
    if (is->audio_st && is->show_mode != SHOW_MODE_VIDEO)
        video_audio_display(is);
    else if (is->video_st)
        video_image_display(is, aux_is);
}

static double get_clock(Clock *c)
{
    if (*c->queue_serial != c->serial)
        return NAN;
    if (c->paused) {
        return c->pts;
    } else {
        double time = av_gettime_relative() / 1000000.0;
        return c->pts_drift + time - (time - c->last_updated) * (1.0 - c->speed);
    }
}

static void set_clock_at(Clock *c, double pts, int serial, double time)
{
    c->pts = pts;
    c->last_updated = time;
    c->pts_drift = c->pts - time;
    c->serial = serial;
}

static void set_clock(Clock *c, double pts, int serial)
{
    double time = av_gettime_relative() / 1000000.0;
    set_clock_at(c, pts, serial, time);
}

static void set_clock_speed(Clock *c, double speed)
{
    set_clock(c, get_clock(c), c->serial);
    c->speed = speed;
}

static void init_clock(Clock *c, int *queue_serial)
{
    c->speed = 1.0;
    c->paused = 0;
    c->queue_serial = queue_serial;
    set_clock(c, NAN, -1);
}

static void sync_clock_to_slave(Clock *c, Clock *slave)
{
    double clock = get_clock(c);
    double slave_clock = get_clock(slave);
    if (!isnan(slave_clock) && (isnan(clock) || fabs(clock - slave_clock) > AV_NOSYNC_THRESHOLD))
        set_clock(c, slave_clock, slave->serial);
}

static int get_master_sync_type(VideoState *is) {
    if (is->av_sync_type == AV_SYNC_VIDEO_MASTER) {
        if (is->video_st)
            return AV_SYNC_VIDEO_MASTER;
        else
            return AV_SYNC_AUDIO_MASTER;
    } else if (is->av_sync_type == AV_SYNC_AUDIO_MASTER) {
        if (is->audio_st)
            return AV_SYNC_AUDIO_MASTER;
        else
            return AV_SYNC_EXTERNAL_CLOCK;
    } else {
        return AV_SYNC_EXTERNAL_CLOCK;
    }
}

/* get the current master clock value */
static double get_master_clock(VideoState *is)
{
    double val;

    switch (get_master_sync_type(is)) {
        case AV_SYNC_VIDEO_MASTER:
            val = get_clock(&is->vidclk);
            break;
        case AV_SYNC_AUDIO_MASTER:
            val = get_clock(&is->audclk);
            break;
        default:
            val = get_clock(&is->extclk);
            break;
    }
    return val;
}

static void check_external_clock_speed(VideoState *is) {
   if (is->video_stream >= 0 && is->videoq.nb_packets <= EXTERNAL_CLOCK_MIN_FRAMES ||
       is->audio_stream >= 0 && is->audioq.nb_packets <= EXTERNAL_CLOCK_MIN_FRAMES) {
       set_clock_speed(&is->extclk, FFMAX(EXTERNAL_CLOCK_SPEED_MIN, is->extclk.speed - EXTERNAL_CLOCK_SPEED_STEP));
   } else if ((is->video_stream < 0 || is->videoq.nb_packets > EXTERNAL_CLOCK_MAX_FRAMES) &&
              (is->audio_stream < 0 || is->audioq.nb_packets > EXTERNAL_CLOCK_MAX_FRAMES)) {
       set_clock_speed(&is->extclk, FFMIN(EXTERNAL_CLOCK_SPEED_MAX, is->extclk.speed + EXTERNAL_CLOCK_SPEED_STEP));
   } else {
       double speed = is->extclk.speed;
       if (speed != 1.0)
           set_clock_speed(&is->extclk, speed + EXTERNAL_CLOCK_SPEED_STEP * (1.0 - speed) / fabs(1.0 - speed));
   }
}

/* seek in the stream */
static void stream_seek(VideoState *is, int64_t pos, int64_t rel, int seek_by_bytes)
{
    if (!is->seek_req) {
        is->seek_pos = pos;
        is->seek_rel = rel;
        is->seek_flags &= ~AVSEEK_FLAG_BYTE;
        if (seek_by_bytes)
            is->seek_flags |= AVSEEK_FLAG_BYTE;
        is->seek_req = 1;
        SDL_CondSignal(is->continue_read_thread);
    }
}

/* pause or resume the video */
static void stream_toggle_pause(VideoState *is)
{
    if (is->paused) {
        is->frame_timer += av_gettime_relative() / 1000000.0 - is->vidclk.last_updated;
        if (is->read_pause_return != AVERROR(ENOSYS)) {
            is->vidclk.paused = 0;
        }
        set_clock(&is->vidclk, get_clock(&is->vidclk), is->vidclk.serial);
    }
    set_clock(&is->extclk, get_clock(&is->extclk), is->extclk.serial);
    is->paused = is->audclk.paused = is->vidclk.paused = is->extclk.paused = !is->paused;
}

static void toggle_pause(VideoState *is)
{
    stream_toggle_pause(is);
    is->step = 0;
}

static void toggle_mute(VideoState *is)
{
    is->muted = !is->muted;
}

static void update_volume(VideoState *is, int sign, int step)
{
    is->audio_volume = av_clip(is->audio_volume + sign * step, 0, SDL_MIX_MAXVOLUME);
}

static void step_to_next_frame(VideoState *is)
{
    /* if the stream is paused unpause it, then step */
    if (is->paused)
        stream_toggle_pause(is);
    is->step = 1;
}

static double compute_target_delay(double delay, VideoState *is)
{
    double sync_threshold, diff = 0;

    /* update delay to follow master synchronisation source */
    if (get_master_sync_type(is) != AV_SYNC_VIDEO_MASTER) {
        /* if video is slave, we try to correct big delays by
           duplicating or deleting a frame */
        diff = get_clock(&is->vidclk) - get_master_clock(is);

        /* skip or repeat frame. We take into account the
           delay to compute the threshold. I still don't know
           if it is the best guess */
        sync_threshold = FFMAX(AV_SYNC_THRESHOLD_MIN, FFMIN(AV_SYNC_THRESHOLD_MAX, delay));
        if (!isnan(diff) && fabs(diff) < is->max_frame_duration) {
            if (diff <= -sync_threshold)
                delay = FFMAX(0, delay + diff);
            else if (diff >= sync_threshold && delay > AV_SYNC_FRAMEDUP_THRESHOLD)
                delay = delay + diff;
            else if (diff >= sync_threshold)
                delay = 2 * delay;
        }
    }

    av_log(NULL, AV_LOG_TRACE, "video: delay=%0.3f A-V=%f\n",
            delay, -diff);

    return delay;
}

static double vp_duration(VideoState *is, Frame *vp, Frame *nextvp) {
    if (vp->serial == nextvp->serial) {
        double duration = nextvp->pts - vp->pts;
        if (isnan(duration) || duration <= 0 || duration > is->max_frame_duration)
            return vp->duration;
        else
            return duration;
    } else {
        return 0.0;
    }
}

static void update_video_pts(VideoState *is, double pts, int64_t pos, int serial) {
    /* update current video pts */
    set_clock(&is->vidclk, pts, serial);
    sync_clock_to_slave(&is->extclk, &is->vidclk);
}

/* called to display each frame */
static void video_refresh(void *opaque, void *aux_opaque, double *remaining_time)
{
    VideoState *is = opaque;
    VideoState *aux_is = aux_opaque;
    double time;

    Frame *sp, *sp2;

    if (!is->paused && get_master_sync_type(is) == AV_SYNC_EXTERNAL_CLOCK && is->realtime)
        check_external_clock_speed(is);

    if (!display_disable && is->show_mode != SHOW_MODE_VIDEO && is->audio_st) {
        time = av_gettime_relative() / 1000000.0;
        if (is->force_refresh || is->last_vis_time + rdftspeed < time) {
            video_display(is, aux_is);
            is->last_vis_time = time;
        }
        *remaining_time = FFMIN(*remaining_time, is->last_vis_time + rdftspeed - time);
    }

    if (is->video_st && (!aux_is || aux_is->video_st)) {
retry:
        if (frame_queue_nb_remaining(&is->pictq) == 0 || (aux_is && frame_queue_nb_remaining(&aux_is->pictq) == 0)) {
            // nothing to do, no picture to display in the queue
        } else {
            double last_duration, duration, delay;
            double aux_duration = 0.0;
            Frame *vp, *lastvp;
            Frame *auxvp = NULL, *auxlastvp = NULL;

            /* dequeue the picture */
            lastvp = frame_queue_peek_last(&is->pictq);
            vp = frame_queue_peek(&is->pictq);
            if(aux_is)
            {
                auxlastvp = frame_queue_peek_last(&aux_is->pictq);
                auxvp = frame_queue_peek(&aux_is->pictq);
            }

            if (vp->serial != is->videoq.serial) {
                frame_queue_next(&is->pictq);
                goto retry;
            }

            if (lastvp->serial != vp->serial)
                is->frame_timer = av_gettime_relative() / 1000000.0;

            if (is->paused)
                goto display;

            /* compute nominal last_duration */
            last_duration = vp_duration(is, lastvp, vp);
            delay = compute_target_delay(last_duration, is);
            if(aux_is)
            {
                aux_duration = vp_duration(aux_is, auxlastvp, auxvp);
            }

            time= av_gettime_relative()/1000000.0;
            if (is->first_pts >= 0 && time < is->frame_timer + delay) { // means current frame arrived too early, need to wait, return remaining_time to wait
                //printf("frame arrived too early: time %f, is->frame_timer + delay %f, diff %f\n", time , is->frame_timer + delay, is->frame_timer + delay - time);
                *remaining_time = FFMIN(is->frame_timer + delay - time, *remaining_time);
                goto display;
            }

            is->frame_timer += delay; // is->frame_timer record display time of last frame
            if (delay > 0 && time - is->frame_timer > AV_SYNC_THRESHOLD_MAX) // current frame arrived too late
                is->frame_timer = time;  // current frame is displayed lately

            SDL_LockMutex(is->pictq.mutex);
            if (!isnan(vp->pts))
                update_video_pts(is, vp->pts, vp->pos, vp->serial);
            SDL_UnlockMutex(is->pictq.mutex);
            
            //printf("remaining_time %f, last_duration %f, delay %f , time %f , is->frame_timer %f, vp->pts %f, vp->pos %lld\n", *remaining_time, last_duration, delay, time , is->frame_timer, vp->pts, vp->pos);

            if (frame_queue_nb_remaining(&is->pictq) > 1) {
                Frame *nextvp = frame_queue_peek_next(&is->pictq);
                duration = vp_duration(is, vp, nextvp);
                if(is->first_pts >= 0 && !is->step && (framedrop>0 || (framedrop && get_master_sync_type(is) != AV_SYNC_VIDEO_MASTER)) && time > is->frame_timer + duration){
                    is->frame_drops_late++;  // current frame is late, drop it
                    frame_queue_next(&is->pictq);
                    goto retry;
                }
            }

            if (is->subtitle_st) {
                    while (frame_queue_nb_remaining(&is->subpq) > 0) {
                        sp = frame_queue_peek(&is->subpq);

                        if (frame_queue_nb_remaining(&is->subpq) > 1)
                            sp2 = frame_queue_peek_next(&is->subpq);
                        else
                            sp2 = NULL;

                        if (sp->serial != is->subtitleq.serial
                                || (is->vidclk.pts > (sp->pts + ((float) sp->sub.end_display_time / 1000)))
                                || (sp2 && is->vidclk.pts > (sp2->pts + ((float) sp2->sub.start_display_time / 1000))))
                        {
                            frame_queue_next(&is->subpq);
                        } else {
                            break;
                        }
                    }
            }

            frame_queue_next(&is->pictq);
            is->force_refresh = 1;
            if(aux_is) 
            {
                if(is->first_pts >= 0 && aux_is->first_pts >= 0) // stream contains pts
                {
                    double auxvp_rela_pts = auxvp->pts - aux_is->first_pts + aux_is->delay_frame_num * aux_duration;
                    double vp_rela_pts = vp->pts - is->first_pts + is->delay_frame_num * last_duration; 
                    while(auxvp_rela_pts <= vp_rela_pts - aux_duration) // aux stream is slower than main stream
                    {
                        if (frame_queue_nb_remaining(&aux_is->pictq) > 1)
                            frame_queue_next(&aux_is->pictq);
                        auxvp = frame_queue_peek(&aux_is->pictq);
                        auxvp_rela_pts = auxvp->pts - aux_is->first_pts + aux_is->delay_frame_num * aux_duration;
                        av_usleep((int64_t)(0.001 * 1000000.0)); // sleep 1ms
                        //av_log(NULL, AV_LOG_INFO, "aux stream is slower than main stream, diff = %f\n", auxvp_rela_pts - vp_rela_pts);
                    }
                    //av_log(NULL, AV_LOG_FATAL, "auxvp->pts %f auxvp_rela_pts %f  |  vp->pts %f, vp_rela_pts %f\n", auxvp->pts, auxvp_rela_pts, vp->pts, vp_rela_pts);
                    if(auxvp_rela_pts < vp_rela_pts + aux_duration) // aux stream is sychronized with main stream
                    {
                        frame_queue_next(&aux_is->pictq);
                        aux_is->force_refresh = 1;
                    }
                    if(auxvp_rela_pts > vp_rela_pts + 2) // if seek back, auxvp_pts would be greater than vp_pts, must empty frame queue of aux_is
                        frame_queue_next(&aux_is->pictq);
                }
                else
                {
                    while(auxvp->dec_frame_num + aux_is->delay_frame_num < vp->dec_frame_num + is->delay_frame_num) // aux stream is slower than main stream
                    {
                        if (frame_queue_nb_remaining(&aux_is->pictq) > 1)
                            frame_queue_next(&aux_is->pictq);
                        auxvp = frame_queue_peek(&aux_is->pictq);
                        av_usleep((int64_t)(0.001 * 1000000.0)); // sleep 1ms
                    }
                    //av_log(NULL, AV_LOG_FATAL, "auxvp->pts %f auxvp_rela_pts %f  |  vp->pts %f, vp_rela_pts %f\n", auxvp->pts, auxvp_rela_pts, vp->pts, vp_rela_pts);
                    if(auxvp->dec_frame_num + aux_is->delay_frame_num < vp->dec_frame_num + is->delay_frame_num + 1) // aux stream is sychronized with main stream
                    {
                        frame_queue_next(&aux_is->pictq);
                        aux_is->force_refresh = 1;
                    }
                }
            }

            if (is->step && !is->paused)
                stream_toggle_pause(is);
            if (aux_is && aux_is->step && !aux_is->paused)
                stream_toggle_pause(aux_is);
        }
display:
        /* display picture */
        if (!display_disable && is->force_refresh && is->show_mode == SHOW_MODE_VIDEO && is->pictq.rindex_shown)
        {
            if(!is->paused || is->step) // TODO: need backup frame data, need to research SDL overlay Mode to emit this operation
            {
                Frame *vp = frame_queue_peek_last(&is->pictq);
                if(vp->bmp)
                {
                    int i;
                    for(i = 0; i < vp->height; i++)
                        memcpy(is->bk_data[0] + i * vp->width, vp->bmp->pixels[0] + i * vp->bmp->pitches[0], vp->width);
                    for(i = 0; i < vp->height / 2; i++)
                    {
                        memcpy(is->bk_data[1] + i * vp->width / 2, vp->bmp->pixels[1] + i * vp->bmp->pitches[1], vp->width / 2);
                        memcpy(is->bk_data[2] + i * vp->width / 2, vp->bmp->pixels[2] + i * vp->bmp->pitches[2], vp->width / 2);
                    }
                }
            }
            video_display(is, aux_is);
        }
    }
    is->force_refresh = 0;
    if (show_status) {
        static int64_t last_time;
        int64_t cur_time;
        int aqsize, vqsize, sqsize;
        double av_diff;

        cur_time = av_gettime_relative();
        if (!last_time || (cur_time - last_time) >= 30000) {
            aqsize = 0;
            vqsize = 0;
            sqsize = 0;
            if (is->audio_st)
                aqsize = is->audioq.size;
            if (is->video_st)
                vqsize = is->videoq.size;
            if (is->subtitle_st)
                sqsize = is->subtitleq.size;
            av_diff = 0;
            if (is->audio_st && is->video_st)
                av_diff = get_clock(&is->audclk) - get_clock(&is->vidclk);
            else if (is->video_st)
                av_diff = get_master_clock(is) - get_clock(&is->vidclk);
            else if (is->audio_st)
                av_diff = get_master_clock(is) - get_clock(&is->audclk);
            av_log(NULL, AV_LOG_INFO,
                   "%7.2f %s:%7.3f fd=%4d aq=%5dKB vq=%5dKB sq=%5dB f=%"PRId64"/%"PRId64"   \r",
                   get_master_clock(is),
                   (is->audio_st && is->video_st) ? "A-V" : (is->video_st ? "M-V" : (is->audio_st ? "M-A" : "   ")),
                   av_diff,
                   is->frame_drops_early + is->frame_drops_late,
                   aqsize / 1024,
                   vqsize / 1024,
                   sqsize,
                   is->video_st ? is->viddec.avctx->pts_correction_num_faulty_dts : 0,
                   is->video_st ? is->viddec.avctx->pts_correction_num_faulty_pts : 0);
            fflush(stdout);
            last_time = cur_time;
        }
    }
}

/* allocate a picture (needs to do that in main thread to avoid
   potential locking problems */
static void alloc_picture(VideoState *is)
{
    Frame *vp;
    int64_t bufferdiff;

    vp = &is->pictq.queue[is->pictq.windex];

    free_picture(vp);

    video_open(is, 0, vp);

    vp->bmp = SDL_CreateYUVOverlay(vp->width, vp->height,
                                   SDL_YV12_OVERLAY,
                                   screen);
    bufferdiff = vp->bmp ? FFMAX(vp->bmp->pixels[0], vp->bmp->pixels[1]) - FFMIN(vp->bmp->pixels[0], vp->bmp->pixels[1]) : 0;
    if (!vp->bmp || vp->bmp->pitches[0] < vp->width || bufferdiff < (int64_t)vp->height * vp->bmp->pitches[0]) {
        /* SDL allocates a buffer smaller than requested if the video
         * overlay hardware is unable to support the requested size. */
        av_log(NULL, AV_LOG_FATAL,
               "Error: the video system does not support an image\n"
                        "size of %dx%d pixels. Try using -lowres or -vf \"scale=w:h\"\n"
                        "to reduce the image size.\n", vp->width, vp->height );
        do_exit(is);
    }

    SDL_LockMutex(is->pictq.mutex);
    vp->allocated = 1;
    SDL_CondSignal(is->pictq.cond);
    SDL_UnlockMutex(is->pictq.mutex);
}

static void duplicate_right_border_pixels(SDL_Overlay *bmp) {
    int i, width, height;
    Uint8 *p, *maxp;
    for (i = 0; i < 3; i++) {
        width  = bmp->w;
        height = bmp->h;
        if (i > 0) {
            width  >>= 1;
            height >>= 1;
        }
        if (bmp->pitches[i] > width) {
            maxp = bmp->pixels[i] + bmp->pitches[i] * height - 1;
            for (p = bmp->pixels[i] + width - 1; p < maxp; p += bmp->pitches[i])
                *(p+1) = *p;
        }
    }
}

static int queue_picture(VideoState *is, AVFrame *src_frame, double pts, double duration, int64_t pos, int serial, long long dec_frame_num)
{
    Frame *vp;

#if defined(DEBUG_SYNC)
    printf("frame_type=%c pts=%0.3f\n",
           av_get_picture_type_char(src_frame->pict_type), pts);
#endif

    if (!(vp = frame_queue_peek_writable(&is->pictq)))
        return -1;

    vp->sar = src_frame->sample_aspect_ratio;
    vp->dec_frame_num = dec_frame_num;

    /* alloc or resize hardware picture buffer */
    if (!vp->bmp || vp->reallocate || !vp->allocated ||
        vp->width  != src_frame->width ||
        vp->height != src_frame->height) {
        SDL_Event event;

        vp->allocated  = 0;
        vp->reallocate = 0;
        vp->width = src_frame->width;
        vp->height = src_frame->height;

        /* the allocation must be done in the main thread to avoid
           locking problems. */
        event.type = FF_ALLOC_EVENT;
        event.user.data1 = is;
        SDL_PushEvent(&event);

        /* wait until the picture is allocated */
        SDL_LockMutex(is->pictq.mutex);
        while (!vp->allocated && !is->videoq.abort_request) {
            SDL_CondWait(is->pictq.cond, is->pictq.mutex);
        }
        /* if the queue is aborted, we have to pop the pending ALLOC event or wait for the allocation to complete */
        if (is->videoq.abort_request && SDL_PeepEvents(&event, 1, SDL_GETEVENT, SDL_EVENTMASK(FF_ALLOC_EVENT)) != 1) {
            while (!vp->allocated && !is->abort_request) {
                SDL_CondWait(is->pictq.cond, is->pictq.mutex);
            }
        }
        SDL_UnlockMutex(is->pictq.mutex);

        if (is->videoq.abort_request)
            return -1;
    }

    /* if the frame is not skipped, then display it */
    if (vp->bmp) {
        uint8_t *data[4];
        int linesize[4];

        /* get a pointer on the bitmap */
        SDL_LockYUVOverlay (vp->bmp);

        data[0] = vp->bmp->pixels[0];
        data[1] = vp->bmp->pixels[2];
        data[2] = vp->bmp->pixels[1];

        linesize[0] = vp->bmp->pitches[0];
        linesize[1] = vp->bmp->pitches[2];
        linesize[2] = vp->bmp->pitches[1];

#if CONFIG_AVFILTER
        // FIXME use direct rendering
        av_image_copy(data, linesize, (const uint8_t **)src_frame->data, src_frame->linesize,
                        src_frame->format, vp->width, vp->height);
#else
        {
            AVDictionaryEntry *e = av_dict_get(sws_dict, "sws_flags", NULL, 0);
            if (e) {
                const AVClass *class = sws_get_class();
                const AVOption    *o = av_opt_find(&class, "sws_flags", NULL, 0,
                                                   AV_OPT_SEARCH_FAKE_OBJ);
                int ret = av_opt_eval_flags(&class, o, e->value, &sws_flags);
                if (ret < 0)
                    exit(1);
            }
        }

        is->img_convert_ctx = sws_getCachedContext(is->img_convert_ctx,
            vp->width, vp->height, src_frame->format, vp->width, vp->height,
            AV_PIX_FMT_YUV420P, sws_flags, NULL, NULL, NULL);
        if (!is->img_convert_ctx) {
            av_log(NULL, AV_LOG_FATAL, "Cannot initialize the conversion context\n");
            exit(1);
        }
        sws_scale(is->img_convert_ctx, src_frame->data, src_frame->linesize,
                  0, vp->height, data, linesize);
#endif
        /* workaround SDL PITCH_WORKAROUND */
        duplicate_right_border_pixels(vp->bmp);
        /* update the bitmap content */
        SDL_UnlockYUVOverlay(vp->bmp);

        vp->pts = pts;
        vp->duration = duration;
        vp->pos = pos;
        vp->serial = serial;

        /* now we can update the picture count */
        frame_queue_push(&is->pictq);
    }
    return 0;
}

static int get_video_frame(VideoState *is, AVFrame *frame)
{
    int got_picture;

    if ((got_picture = decoder_decode_frame(&is->viddec, frame, NULL)) < 0)
        return -1;

    if (got_picture) {
        double dpts = NAN;

        if (frame->pts != AV_NOPTS_VALUE)
            dpts = av_q2d(is->video_st->time_base) * frame->pts;

        frame->sample_aspect_ratio = av_guess_sample_aspect_ratio(is->ic, is->video_st, frame);

        is->viddec_width  = frame->width;
        is->viddec_height = frame->height;

        if (framedrop>0 || (framedrop && get_master_sync_type(is) != AV_SYNC_VIDEO_MASTER)) {
            if (frame->pts != AV_NOPTS_VALUE) {
                double diff = dpts - get_master_clock(is);
                if (!isnan(diff) && fabs(diff) < AV_NOSYNC_THRESHOLD &&
                    diff - is->frame_last_filter_delay < 0 &&
                    is->viddec.pkt_serial == is->vidclk.serial &&
                    is->videoq.nb_packets) {
                    is->frame_drops_early++;
                    av_frame_unref(frame);
                    got_picture = 0;
                }
            }
        }
    }

    return got_picture;
}

#if CONFIG_AVFILTER
static int configure_filtergraph(AVFilterGraph *graph, const char *filtergraph,
                                 AVFilterContext *source_ctx, AVFilterContext *sink_ctx)
{
    int ret, i;
    int nb_filters = graph->nb_filters;
    AVFilterInOut *outputs = NULL, *inputs = NULL;

    if (filtergraph) {
        outputs = avfilter_inout_alloc();
        inputs  = avfilter_inout_alloc();
        if (!outputs || !inputs) {
            ret = AVERROR(ENOMEM);
            goto fail;
        }

        outputs->name       = av_strdup("in");
        outputs->filter_ctx = source_ctx;
        outputs->pad_idx    = 0;
        outputs->next       = NULL;

        inputs->name        = av_strdup("out");
        inputs->filter_ctx  = sink_ctx;
        inputs->pad_idx     = 0;
        inputs->next        = NULL;

        if ((ret = avfilter_graph_parse_ptr(graph, filtergraph, &inputs, &outputs, NULL)) < 0)
            goto fail;
    } else {
        if ((ret = avfilter_link(source_ctx, 0, sink_ctx, 0)) < 0)
            goto fail;
    }

    /* Reorder the filters to ensure that inputs of the custom filters are merged first */
    for (i = 0; i < graph->nb_filters - nb_filters; i++)
        FFSWAP(AVFilterContext*, graph->filters[i], graph->filters[i + nb_filters]);

    ret = avfilter_graph_config(graph, NULL);
fail:
    avfilter_inout_free(&outputs);
    avfilter_inout_free(&inputs);
    return ret;
}

static int configure_video_filters(AVFilterGraph *graph, VideoState *is, const char *vfilters, AVFrame *frame)
{
    static const enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_YUV420P, AV_PIX_FMT_NONE };
    char sws_flags_str[512] = "";
    char buffersrc_args[256];
    int ret;
    AVFilterContext *filt_src = NULL, *filt_out = NULL, *last_filter = NULL;
    AVCodecParameters *codecpar = is->video_st->codecpar;
    AVRational fr = av_guess_frame_rate(is->ic, is->video_st, NULL);
    AVDictionaryEntry *e = NULL;

    while ((e = av_dict_get(sws_dict, "", e, AV_DICT_IGNORE_SUFFIX))) {
        if (!strcmp(e->key, "sws_flags")) {
            av_strlcatf(sws_flags_str, sizeof(sws_flags_str), "%s=%s:", "flags", e->value);
        } else
            av_strlcatf(sws_flags_str, sizeof(sws_flags_str), "%s=%s:", e->key, e->value);
    }
    if (strlen(sws_flags_str))
        sws_flags_str[strlen(sws_flags_str)-1] = '\0';

    graph->scale_sws_opts = av_strdup(sws_flags_str);

    snprintf(buffersrc_args, sizeof(buffersrc_args),
             "video_size=%dx%d:pix_fmt=%d:time_base=%d/%d:pixel_aspect=%d/%d",
             frame->width, frame->height, frame->format,
             is->video_st->time_base.num, is->video_st->time_base.den,
             codecpar->sample_aspect_ratio.num, FFMAX(codecpar->sample_aspect_ratio.den, 1));
    if (fr.num && fr.den)
        av_strlcatf(buffersrc_args, sizeof(buffersrc_args), ":frame_rate=%d/%d", fr.num, fr.den);

    if ((ret = avfilter_graph_create_filter(&filt_src,
                                            avfilter_get_by_name("buffer"),
                                            "ffplay_buffer", buffersrc_args, NULL,
                                            graph)) < 0)
        goto fail;

    ret = avfilter_graph_create_filter(&filt_out,
                                       avfilter_get_by_name("buffersink"),
                                       "ffplay_buffersink", NULL, NULL, graph);
    if (ret < 0)
        goto fail;

    if ((ret = av_opt_set_int_list(filt_out, "pix_fmts", pix_fmts,  AV_PIX_FMT_NONE, AV_OPT_SEARCH_CHILDREN)) < 0)
        goto fail;

    last_filter = filt_out;

/* Note: this macro adds a filter before the lastly added filter, so the
 * processing order of the filters is in reverse */
#define INSERT_FILT(name, arg) do {                                          \
    AVFilterContext *filt_ctx;                                               \
                                                                             \
    ret = avfilter_graph_create_filter(&filt_ctx,                            \
                                       avfilter_get_by_name(name),           \
                                       "ffplay_" name, arg, NULL, graph);    \
    if (ret < 0)                                                             \
        goto fail;                                                           \
                                                                             \
    ret = avfilter_link(filt_ctx, 0, last_filter, 0);                        \
    if (ret < 0)                                                             \
        goto fail;                                                           \
                                                                             \
    last_filter = filt_ctx;                                                  \
} while (0)

    /* SDL YUV code is not handling odd width/height for some driver
     * combinations, therefore we crop the picture to an even width/height. */
    INSERT_FILT("crop", "floor(in_w/2)*2:floor(in_h/2)*2");

    if (autorotate) {
        double theta  = get_rotation(is->video_st);

        if (fabs(theta - 90) < 1.0) {
            INSERT_FILT("transpose", "clock");
        } else if (fabs(theta - 180) < 1.0) {
            INSERT_FILT("hflip", NULL);
            INSERT_FILT("vflip", NULL);
        } else if (fabs(theta - 270) < 1.0) {
            INSERT_FILT("transpose", "cclock");
        } else if (fabs(theta) > 1.0) {
            char rotate_buf[64];
            snprintf(rotate_buf, sizeof(rotate_buf), "%f*PI/180", theta);
            INSERT_FILT("rotate", rotate_buf);
        }
    }

    if ((ret = configure_filtergraph(graph, vfilters, filt_src, last_filter)) < 0)
        goto fail;

    is->in_video_filter  = filt_src;
    is->out_video_filter = filt_out;

fail:
    return ret;
}

static int configure_audio_filters(VideoState *is, const char *afilters, int force_output_format)
{
    static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_NONE };
    int sample_rates[2] = { 0, -1 };
    int64_t channel_layouts[2] = { 0, -1 };
    int channels[2] = { 0, -1 };
    AVFilterContext *filt_asrc = NULL, *filt_asink = NULL;
    char aresample_swr_opts[512] = "";
    AVDictionaryEntry *e = NULL;
    char asrc_args[256];
    int ret;

    avfilter_graph_free(&is->agraph);
    if (!(is->agraph = avfilter_graph_alloc()))
        return AVERROR(ENOMEM);

    while ((e = av_dict_get(swr_opts, "", e, AV_DICT_IGNORE_SUFFIX)))
        av_strlcatf(aresample_swr_opts, sizeof(aresample_swr_opts), "%s=%s:", e->key, e->value);
    if (strlen(aresample_swr_opts))
        aresample_swr_opts[strlen(aresample_swr_opts)-1] = '\0';
    av_opt_set(is->agraph, "aresample_swr_opts", aresample_swr_opts, 0);

    ret = snprintf(asrc_args, sizeof(asrc_args),
                   "sample_rate=%d:sample_fmt=%s:channels=%d:time_base=%d/%d",
                   is->audio_filter_src.freq, av_get_sample_fmt_name(is->audio_filter_src.fmt),
                   is->audio_filter_src.channels,
                   1, is->audio_filter_src.freq);
    if (is->audio_filter_src.channel_layout)
        snprintf(asrc_args + ret, sizeof(asrc_args) - ret,
                 ":channel_layout=0x%"PRIx64,  is->audio_filter_src.channel_layout);

    ret = avfilter_graph_create_filter(&filt_asrc,
                                       avfilter_get_by_name("abuffer"), "ffplay_abuffer",
                                       asrc_args, NULL, is->agraph);
    if (ret < 0)
        goto end;


    ret = avfilter_graph_create_filter(&filt_asink,
                                       avfilter_get_by_name("abuffersink"), "ffplay_abuffersink",
                                       NULL, NULL, is->agraph);
    if (ret < 0)
        goto end;

    if ((ret = av_opt_set_int_list(filt_asink, "sample_fmts", sample_fmts,  AV_SAMPLE_FMT_NONE, AV_OPT_SEARCH_CHILDREN)) < 0)
        goto end;
    if ((ret = av_opt_set_int(filt_asink, "all_channel_counts", 1, AV_OPT_SEARCH_CHILDREN)) < 0)
        goto end;

    if (force_output_format) {
        channel_layouts[0] = is->audio_tgt.channel_layout;
        channels       [0] = is->audio_tgt.channels;
        sample_rates   [0] = is->audio_tgt.freq;
        if ((ret = av_opt_set_int(filt_asink, "all_channel_counts", 0, AV_OPT_SEARCH_CHILDREN)) < 0)
            goto end;
        if ((ret = av_opt_set_int_list(filt_asink, "channel_layouts", channel_layouts,  -1, AV_OPT_SEARCH_CHILDREN)) < 0)
            goto end;
        if ((ret = av_opt_set_int_list(filt_asink, "channel_counts" , channels       ,  -1, AV_OPT_SEARCH_CHILDREN)) < 0)
            goto end;
        if ((ret = av_opt_set_int_list(filt_asink, "sample_rates"   , sample_rates   ,  -1, AV_OPT_SEARCH_CHILDREN)) < 0)
            goto end;
    }


    if ((ret = configure_filtergraph(is->agraph, afilters, filt_asrc, filt_asink)) < 0)
        goto end;

    is->in_audio_filter  = filt_asrc;
    is->out_audio_filter = filt_asink;

end:
    if (ret < 0)
        avfilter_graph_free(&is->agraph);
    return ret;
}
#endif  /* CONFIG_AVFILTER */

static int audio_thread(void *arg)
{
    VideoState *is = arg;
    AVFrame *frame = av_frame_alloc();
    Frame *af;
#if CONFIG_AVFILTER
    int last_serial = -1;
    int64_t dec_channel_layout;
    int reconfigure;
#endif
    int got_frame = 0;
    AVRational tb;
    int ret = 0;

    if (!frame)
        return AVERROR(ENOMEM);

    do {
        if ((got_frame = decoder_decode_frame(&is->auddec, frame, NULL)) < 0)
            goto the_end;

        if (got_frame) {
                tb = (AVRational){1, frame->sample_rate};

#if CONFIG_AVFILTER
                dec_channel_layout = get_valid_channel_layout(frame->channel_layout, av_frame_get_channels(frame));

                reconfigure =
                    cmp_audio_fmts(is->audio_filter_src.fmt, is->audio_filter_src.channels,
                                   frame->format, av_frame_get_channels(frame))    ||
                    is->audio_filter_src.channel_layout != dec_channel_layout ||
                    is->audio_filter_src.freq           != frame->sample_rate ||
                    is->auddec.pkt_serial               != last_serial;

                if (reconfigure) {
                    char buf1[1024], buf2[1024];
                    av_get_channel_layout_string(buf1, sizeof(buf1), -1, is->audio_filter_src.channel_layout);
                    av_get_channel_layout_string(buf2, sizeof(buf2), -1, dec_channel_layout);
                    av_log(NULL, AV_LOG_DEBUG,
                           "Audio frame changed from rate:%d ch:%d fmt:%s layout:%s serial:%d to rate:%d ch:%d fmt:%s layout:%s serial:%d\n",
                           is->audio_filter_src.freq, is->audio_filter_src.channels, av_get_sample_fmt_name(is->audio_filter_src.fmt), buf1, last_serial,
                           frame->sample_rate, av_frame_get_channels(frame), av_get_sample_fmt_name(frame->format), buf2, is->auddec.pkt_serial);

                    is->audio_filter_src.fmt            = frame->format;
                    is->audio_filter_src.channels       = av_frame_get_channels(frame);
                    is->audio_filter_src.channel_layout = dec_channel_layout;
                    is->audio_filter_src.freq           = frame->sample_rate;
                    last_serial                         = is->auddec.pkt_serial;

                    if ((ret = configure_audio_filters(is, afilters, 1)) < 0)
                        goto the_end;
                }

            if ((ret = av_buffersrc_add_frame(is->in_audio_filter, frame)) < 0)
                goto the_end;

            while ((ret = av_buffersink_get_frame_flags(is->out_audio_filter, frame, 0)) >= 0) {
                tb = is->out_audio_filter->inputs[0]->time_base;
#endif
                if (!(af = frame_queue_peek_writable(&is->sampq)))
                    goto the_end;

                af->pts = (frame->pts == AV_NOPTS_VALUE) ? NAN : frame->pts * av_q2d(tb);
                af->pos = av_frame_get_pkt_pos(frame);
                af->serial = is->auddec.pkt_serial;
                af->duration = av_q2d((AVRational){frame->nb_samples, frame->sample_rate});

                av_frame_move_ref(af->frame, frame);
                frame_queue_push(&is->sampq);

#if CONFIG_AVFILTER
                if (is->audioq.serial != is->auddec.pkt_serial)
                    break;
            }
            if (ret == AVERROR_EOF)
                is->auddec.finished = is->auddec.pkt_serial;
#endif
        }
    } while (ret >= 0 || ret == AVERROR(EAGAIN) || ret == AVERROR_EOF);
 the_end:
#if CONFIG_AVFILTER
    avfilter_graph_free(&is->agraph);
#endif
    av_frame_free(&frame);
    return ret;
}

static int decoder_start(Decoder *d, int (*fn)(void *), void *arg)
{
    packet_queue_start(d->queue);
    d->decoder_tid = SDL_CreateThread(fn, arg);
    if (!d->decoder_tid) {
        av_log(NULL, AV_LOG_ERROR, "SDL_CreateThread(): %s\n", SDL_GetError());
        return AVERROR(ENOMEM);
    }
    return 0;
}

static int video_thread(void *arg)
{
    VideoState *is = arg;
    AVFrame *frame = av_frame_alloc();
    AVFrame *scaleFrame = NULL;
    AVFrame   *outframe = NULL; // final output frame for queue_picture
    struct SwsContext *sws_ctx = NULL;
    double pts;
    double duration;
    long long dec_frame_num = 0;
    int ret;
    AVRational tb = is->video_st->time_base;
    AVRational frame_rate = av_guess_frame_rate(is->ic, is->video_st, NULL);

#if CONFIG_AVFILTER
    AVFilterGraph *graph = avfilter_graph_alloc();
    AVFilterContext *filt_out = NULL, *filt_in = NULL;
    int last_w = 0;
    int last_h = 0;
    enum AVPixelFormat last_format = -2;
    int last_serial = -1;
    int last_vfilter_idx = 0;
    if (!graph) {
        av_frame_free(&frame);
        return AVERROR(ENOMEM);
    }
#endif

    if (!frame) {
#if CONFIG_AVFILTER
        avfilter_graph_free(&graph);
#endif
        return AVERROR(ENOMEM);
    }
    
    for (;;) {
        ret = get_video_frame(is, frame);
        if (ret < 0)
            goto the_end;
        if (!ret)
            continue;
            
        dec_frame_num++;
        outframe = frame;
        
        // frame may need scale
        if(scaleFrame == NULL && (is->viddec_width != is->scaleto_width || is->viddec_height != is->scaleto_height))
        {
            scaleFrame = av_frame_alloc();
            if(scaleFrame)
            {
                scaleFrame->format = frame->format;
                scaleFrame->width  = is->scaleto_width;
                scaleFrame->height = is->scaleto_height;
                ret = av_frame_get_buffer(scaleFrame, 32);
                if(ret < 0)
                    scaleFrame = NULL;
            }
       	 }
         if(scaleFrame)
         {
             sws_ctx = sws_getCachedContext(sws_ctx, is->viddec_width, is->viddec_height, frame->format, 
                                            is->scaleto_width, is->scaleto_height, frame->format, 
                                            SWS_BILINEAR, NULL, NULL, NULL);
             sws_scale(sws_ctx, (const uint8_t * const*)frame->data, frame->linesize, 0, frame->height, 
                       (const uint8_t * const*)scaleFrame->data, scaleFrame->linesize);
             av_frame_copy_props(scaleFrame, frame);
             outframe = scaleFrame;
         }
        
#if CONFIG_AVFILTER
        if (   last_w != outframe->width
            || last_h != outframe->height
            || last_format != outframe->format
            || last_serial != is->viddec.pkt_serial
            || last_vfilter_idx != is->vfilter_idx) {
            av_log(NULL, AV_LOG_DEBUG,
                   "Video frame changed from size:%dx%d format:%s serial:%d to size:%dx%d format:%s serial:%d\n",
                   last_w, last_h,
                   (const char *)av_x_if_null(av_get_pix_fmt_name(last_format), "none"), last_serial,
                   outframe->width, outframe->height,
                   (const char *)av_x_if_null(av_get_pix_fmt_name(outframe->format), "none"), is->viddec.pkt_serial);
            avfilter_graph_free(&graph);
            graph = avfilter_graph_alloc();
            if ((ret = configure_video_filters(graph, is, vfilters_list ? vfilters_list[is->vfilter_idx] : NULL, frame)) < 0) {
                SDL_Event event;
                event.type = FF_QUIT_EVENT;
                event.user.data1 = is;
                SDL_PushEvent(&event);
                goto the_end;
            }
            filt_in  = is->in_video_filter;
            filt_out = is->out_video_filter;
            last_w = outframe->width;
            last_h = outframe->height;
            last_format = outframe->format;
            last_serial = is->viddec.pkt_serial;
            last_vfilter_idx = is->vfilter_idx;
            frame_rate = filt_out->inputs[0]->frame_rate;
        }

        ret = av_buffersrc_add_frame(filt_in, frame);
        if (ret < 0)
            goto the_end;

        while (ret >= 0) {
            is->frame_last_returned_time = av_gettime_relative() / 1000000.0;

            ret = av_buffersink_get_frame_flags(filt_out, frame, 0);
            if (ret < 0) {
                if (ret == AVERROR_EOF)
                    is->viddec.finished = is->viddec.pkt_serial;
                ret = 0;
                break;
            }

            is->frame_last_filter_delay = av_gettime_relative() / 1000000.0 - is->frame_last_returned_time;
            if (fabs(is->frame_last_filter_delay) > AV_NOSYNC_THRESHOLD / 10.0)
                is->frame_last_filter_delay = 0;
            tb = filt_out->inputs[0]->time_base;
#endif
            duration = (frame_rate.num && frame_rate.den ? av_q2d((AVRational){frame_rate.den, frame_rate.num}) : 0);
            pts = (frame->pts == AV_NOPTS_VALUE) ? NAN : frame->pts * av_q2d(tb);
            if(scaleFrame)
                ret = queue_picture(is, outframe, pts, duration, av_frame_get_pkt_pos(outframe), is->viddec.pkt_serial, dec_frame_num);
            else
                ret = queue_picture(is, frame, pts, duration, av_frame_get_pkt_pos(frame), is->viddec.pkt_serial, dec_frame_num);
            if(is->first_pts < 0 && frame->pts != AV_NOPTS_VALUE)
                is->first_pts = pts;
            av_frame_unref(frame);
#if CONFIG_AVFILTER
        }
#endif

        if (ret < 0)
            goto the_end;
    }
 the_end:
#if CONFIG_AVFILTER
    avfilter_graph_free(&graph);
#endif
    av_frame_free(&frame);
    av_frame_free(&scaleFrame);

    return 0;
}

static int subtitle_thread(void *arg)
{
    VideoState *is = arg;
    Frame *sp;
    int got_subtitle;
    double pts;
    int i;

    for (;;) {
        if (!(sp = frame_queue_peek_writable(&is->subpq)))
            return 0;

        if ((got_subtitle = decoder_decode_frame(&is->subdec, NULL, &sp->sub)) < 0)
            break;

        pts = 0;

        if (got_subtitle && sp->sub.format == 0) {
            if (sp->sub.pts != AV_NOPTS_VALUE)
                pts = sp->sub.pts / (double)AV_TIME_BASE;
            sp->pts = pts;
            sp->serial = is->subdec.pkt_serial;
            if (!(sp->subrects = av_mallocz_array(sp->sub.num_rects, sizeof(AVSubtitleRect*)))) {
                av_log(NULL, AV_LOG_FATAL, "Cannot allocate subrects\n");
                exit(1);
            }

            for (i = 0; i < sp->sub.num_rects; i++)
            {
                int in_w = sp->sub.rects[i]->w;
                int in_h = sp->sub.rects[i]->h;
                int subw = is->subdec.avctx->width  ? is->subdec.avctx->width  : is->viddec_width;
                int subh = is->subdec.avctx->height ? is->subdec.avctx->height : is->viddec_height;
                int out_w = is->viddec_width  ? in_w * is->viddec_width  / subw : in_w;
                int out_h = is->viddec_height ? in_h * is->viddec_height / subh : in_h;

                if (!(sp->subrects[i] = av_mallocz(sizeof(AVSubtitleRect))) ||
                    av_image_alloc(sp->subrects[i]->data, sp->subrects[i]->linesize, out_w, out_h, AV_PIX_FMT_YUVA420P, 16) < 0) {
                    av_log(NULL, AV_LOG_FATAL, "Cannot allocate subtitle data\n");
                    exit(1);
                }

                is->sub_convert_ctx = sws_getCachedContext(is->sub_convert_ctx,
                    in_w, in_h, AV_PIX_FMT_PAL8, out_w, out_h,
                    AV_PIX_FMT_YUVA420P, sws_flags, NULL, NULL, NULL);
                if (!is->sub_convert_ctx) {
                    av_log(NULL, AV_LOG_FATAL, "Cannot initialize the sub conversion context\n");
                    exit(1);
                }
                sws_scale(is->sub_convert_ctx,
                          (void*)sp->sub.rects[i]->data, sp->sub.rects[i]->linesize,
                          0, in_h, sp->subrects[i]->data, sp->subrects[i]->linesize);

                sp->subrects[i]->w = out_w;
                sp->subrects[i]->h = out_h;
                sp->subrects[i]->x = sp->sub.rects[i]->x * out_w / in_w;
                sp->subrects[i]->y = sp->sub.rects[i]->y * out_h / in_h;
            }

            /* now we can update the picture count */
            frame_queue_push(&is->subpq);
        } else if (got_subtitle) {
            avsubtitle_free(&sp->sub);
        }
    }
    return 0;
}

/* copy samples for viewing in editor window */
static void update_sample_display(VideoState *is, short *samples, int samples_size)
{
    int size, len;

    size = samples_size / sizeof(short);
    while (size > 0) {
        len = SAMPLE_ARRAY_SIZE - is->sample_array_index;
        if (len > size)
            len = size;
        memcpy(is->sample_array + is->sample_array_index, samples, len * sizeof(short));
        samples += len;
        is->sample_array_index += len;
        if (is->sample_array_index >= SAMPLE_ARRAY_SIZE)
            is->sample_array_index = 0;
        size -= len;
    }
}

/* return the wanted number of samples to get better sync if sync_type is video
 * or external master clock */
static int synchronize_audio(VideoState *is, int nb_samples)
{
    int wanted_nb_samples = nb_samples;

    /* if not master, then we try to remove or add samples to correct the clock */
    if (get_master_sync_type(is) != AV_SYNC_AUDIO_MASTER) {
        double diff, avg_diff;
        int min_nb_samples, max_nb_samples;

        diff = get_clock(&is->audclk) - get_master_clock(is);

        if (!isnan(diff) && fabs(diff) < AV_NOSYNC_THRESHOLD) {
            is->audio_diff_cum = diff + is->audio_diff_avg_coef * is->audio_diff_cum;
            if (is->audio_diff_avg_count < AUDIO_DIFF_AVG_NB) {
                /* not enough measures to have a correct estimate */
                is->audio_diff_avg_count++;
            } else {
                /* estimate the A-V difference */
                avg_diff = is->audio_diff_cum * (1.0 - is->audio_diff_avg_coef);

                if (fabs(avg_diff) >= is->audio_diff_threshold) {
                    wanted_nb_samples = nb_samples + (int)(diff * is->audio_src.freq);
                    min_nb_samples = ((nb_samples * (100 - SAMPLE_CORRECTION_PERCENT_MAX) / 100));
                    max_nb_samples = ((nb_samples * (100 + SAMPLE_CORRECTION_PERCENT_MAX) / 100));
                    wanted_nb_samples = av_clip(wanted_nb_samples, min_nb_samples, max_nb_samples);
                }
                av_log(NULL, AV_LOG_TRACE, "diff=%f adiff=%f sample_diff=%d apts=%0.3f %f\n",
                        diff, avg_diff, wanted_nb_samples - nb_samples,
                        is->audio_clock, is->audio_diff_threshold);
            }
        } else {
            /* too big difference : may be initial PTS errors, so
               reset A-V filter */
            is->audio_diff_avg_count = 0;
            is->audio_diff_cum       = 0;
        }
    }

    return wanted_nb_samples;
}

/**
 * Decode one audio frame and return its uncompressed size.
 *
 * The processed audio frame is decoded, converted if required, and
 * stored in is->audio_buf, with size in bytes given by the return
 * value.
 */
static int audio_decode_frame(VideoState *is)
{
    int data_size, resampled_data_size;
    int64_t dec_channel_layout;
    av_unused double audio_clock0;
    int wanted_nb_samples;
    Frame *af;

    if (is->paused)
        return -1;

    do {
#if defined(_WIN32)
        while (frame_queue_nb_remaining(&is->sampq) == 0) {
            if ((av_gettime_relative() - audio_callback_time) > 1000000LL * is->audio_hw_buf_size / is->audio_tgt.bytes_per_sec / 2)
                return -1;
            av_usleep (1000);
        }
#endif
        if (!(af = frame_queue_peek_readable(&is->sampq)))
            return -1;
        frame_queue_next(&is->sampq);
    } while (af->serial != is->audioq.serial);

    data_size = av_samples_get_buffer_size(NULL, av_frame_get_channels(af->frame),
                                           af->frame->nb_samples,
                                           af->frame->format, 1);

    dec_channel_layout =
        (af->frame->channel_layout && av_frame_get_channels(af->frame) == av_get_channel_layout_nb_channels(af->frame->channel_layout)) ?
        af->frame->channel_layout : av_get_default_channel_layout(av_frame_get_channels(af->frame));
    wanted_nb_samples = synchronize_audio(is, af->frame->nb_samples);

    if (af->frame->format        != is->audio_src.fmt            ||
        dec_channel_layout       != is->audio_src.channel_layout ||
        af->frame->sample_rate   != is->audio_src.freq           ||
        (wanted_nb_samples       != af->frame->nb_samples && !is->swr_ctx)) {
        swr_free(&is->swr_ctx);
        is->swr_ctx = swr_alloc_set_opts(NULL,
                                         is->audio_tgt.channel_layout, is->audio_tgt.fmt, is->audio_tgt.freq,
                                         dec_channel_layout,           af->frame->format, af->frame->sample_rate,
                                         0, NULL);
        if (!is->swr_ctx || swr_init(is->swr_ctx) < 0) {
            av_log(NULL, AV_LOG_ERROR,
                   "Cannot create sample rate converter for conversion of %d Hz %s %d channels to %d Hz %s %d channels!\n",
                    af->frame->sample_rate, av_get_sample_fmt_name(af->frame->format), av_frame_get_channels(af->frame),
                    is->audio_tgt.freq, av_get_sample_fmt_name(is->audio_tgt.fmt), is->audio_tgt.channels);
            swr_free(&is->swr_ctx);
            return -1;
        }
        is->audio_src.channel_layout = dec_channel_layout;
        is->audio_src.channels       = av_frame_get_channels(af->frame);
        is->audio_src.freq = af->frame->sample_rate;
        is->audio_src.fmt = af->frame->format;
    }

    if (is->swr_ctx) {
        const uint8_t **in = (const uint8_t **)af->frame->extended_data;
        uint8_t **out = &is->audio_buf1;
        int out_count = (int64_t)wanted_nb_samples * is->audio_tgt.freq / af->frame->sample_rate + 256;
        int out_size  = av_samples_get_buffer_size(NULL, is->audio_tgt.channels, out_count, is->audio_tgt.fmt, 0);
        int len2;
        if (out_size < 0) {
            av_log(NULL, AV_LOG_ERROR, "av_samples_get_buffer_size() failed\n");
            return -1;
        }
        if (wanted_nb_samples != af->frame->nb_samples) {
            if (swr_set_compensation(is->swr_ctx, (wanted_nb_samples - af->frame->nb_samples) * is->audio_tgt.freq / af->frame->sample_rate,
                                        wanted_nb_samples * is->audio_tgt.freq / af->frame->sample_rate) < 0) {
                av_log(NULL, AV_LOG_ERROR, "swr_set_compensation() failed\n");
                return -1;
            }
        }
        av_fast_malloc(&is->audio_buf1, &is->audio_buf1_size, out_size);
        if (!is->audio_buf1)
            return AVERROR(ENOMEM);
        len2 = swr_convert(is->swr_ctx, out, out_count, in, af->frame->nb_samples);
        if (len2 < 0) {
            av_log(NULL, AV_LOG_ERROR, "swr_convert() failed\n");
            return -1;
        }
        if (len2 == out_count) {
            av_log(NULL, AV_LOG_WARNING, "audio buffer is probably too small\n");
            if (swr_init(is->swr_ctx) < 0)
                swr_free(&is->swr_ctx);
        }
        is->audio_buf = is->audio_buf1;
        resampled_data_size = len2 * is->audio_tgt.channels * av_get_bytes_per_sample(is->audio_tgt.fmt);
    } else {
        is->audio_buf = af->frame->data[0];
        resampled_data_size = data_size;
    }

    audio_clock0 = is->audio_clock;
    /* update the audio clock with the pts */
    if (!isnan(af->pts))
        is->audio_clock = af->pts + (double) af->frame->nb_samples / af->frame->sample_rate;
    else
        is->audio_clock = NAN;
    is->audio_clock_serial = af->serial;
#ifdef DEBUG
    {
        static double last_clock;
        printf("audio: delay=%0.3f clock=%0.3f clock0=%0.3f\n",
               is->audio_clock - last_clock,
               is->audio_clock, audio_clock0);
        last_clock = is->audio_clock;
    }
#endif
    return resampled_data_size;
}

/* prepare a new audio buffer */
static void sdl_audio_callback(void *opaque, Uint8 *stream, int len)
{
    VideoState *is = opaque;
    int audio_size, len1;

    audio_callback_time = av_gettime_relative();

    while (len > 0) {
        if (is->audio_buf_index >= is->audio_buf_size) {
           audio_size = audio_decode_frame(is);
           if (audio_size < 0) {
                /* if error, just output silence */
               is->audio_buf = NULL;
               is->audio_buf_size = SDL_AUDIO_MIN_BUFFER_SIZE / is->audio_tgt.frame_size * is->audio_tgt.frame_size;
           } else {
               if (is->show_mode != SHOW_MODE_VIDEO)
                   update_sample_display(is, (int16_t *)is->audio_buf, audio_size);
               is->audio_buf_size = audio_size;
           }
           is->audio_buf_index = 0;
        }
        len1 = is->audio_buf_size - is->audio_buf_index;
        if (len1 > len)
            len1 = len;
        if (!is->muted && is->audio_buf && is->audio_volume == SDL_MIX_MAXVOLUME)
            memcpy(stream, (uint8_t *)is->audio_buf + is->audio_buf_index, len1);
        else {
            memset(stream, 0, len1);
            if (!is->muted && is->audio_buf)
                SDL_MixAudio(stream, (uint8_t *)is->audio_buf + is->audio_buf_index, len1, is->audio_volume);
        }
        len -= len1;
        stream += len1;
        is->audio_buf_index += len1;
    }
    is->audio_write_buf_size = is->audio_buf_size - is->audio_buf_index;
    /* Let's assume the audio driver that is used by SDL has two periods. */
    if (!isnan(is->audio_clock)) {
        set_clock_at(&is->audclk, is->audio_clock - (double)(2 * is->audio_hw_buf_size + is->audio_write_buf_size) / is->audio_tgt.bytes_per_sec, is->audio_clock_serial, audio_callback_time / 1000000.0);
        sync_clock_to_slave(&is->extclk, &is->audclk);
    }
}

static int audio_open(void *opaque, int64_t wanted_channel_layout, int wanted_nb_channels, int wanted_sample_rate, struct AudioParams *audio_hw_params)
{
    SDL_AudioSpec wanted_spec, spec;
    const char *env;
    static const int next_nb_channels[] = {0, 0, 1, 6, 2, 6, 4, 6};
    static const int next_sample_rates[] = {0, 44100, 48000, 96000, 192000};
    int next_sample_rate_idx = FF_ARRAY_ELEMS(next_sample_rates) - 1;

    env = SDL_getenv("SDL_AUDIO_CHANNELS");
    if (env) {
        wanted_nb_channels = atoi(env);
        wanted_channel_layout = av_get_default_channel_layout(wanted_nb_channels);
    }
    if (!wanted_channel_layout || wanted_nb_channels != av_get_channel_layout_nb_channels(wanted_channel_layout)) {
        wanted_channel_layout = av_get_default_channel_layout(wanted_nb_channels);
        wanted_channel_layout &= ~AV_CH_LAYOUT_STEREO_DOWNMIX;
    }
    wanted_nb_channels = av_get_channel_layout_nb_channels(wanted_channel_layout);
    wanted_spec.channels = wanted_nb_channels;
    wanted_spec.freq = wanted_sample_rate;
    if (wanted_spec.freq <= 0 || wanted_spec.channels <= 0) {
        av_log(NULL, AV_LOG_ERROR, "Invalid sample rate or channel count!\n");
        return -1;
    }
    while (next_sample_rate_idx && next_sample_rates[next_sample_rate_idx] >= wanted_spec.freq)
        next_sample_rate_idx--;
    wanted_spec.format = AUDIO_S16SYS;
    wanted_spec.silence = 0;
    wanted_spec.samples = FFMAX(SDL_AUDIO_MIN_BUFFER_SIZE, 2 << av_log2(wanted_spec.freq / SDL_AUDIO_MAX_CALLBACKS_PER_SEC));
    wanted_spec.callback = sdl_audio_callback;
    wanted_spec.userdata = opaque;
    while (SDL_OpenAudio(&wanted_spec, &spec) < 0) {
        av_log(NULL, AV_LOG_WARNING, "SDL_OpenAudio (%d channels, %d Hz): %s\n",
               wanted_spec.channels, wanted_spec.freq, SDL_GetError());
        wanted_spec.channels = next_nb_channels[FFMIN(7, wanted_spec.channels)];
        if (!wanted_spec.channels) {
            wanted_spec.freq = next_sample_rates[next_sample_rate_idx--];
            wanted_spec.channels = wanted_nb_channels;
            if (!wanted_spec.freq) {
                av_log(NULL, AV_LOG_ERROR,
                       "No more combinations to try, audio open failed\n");
                return -1;
            }
        }
        wanted_channel_layout = av_get_default_channel_layout(wanted_spec.channels);
    }
    if (spec.format != AUDIO_S16SYS) {
        av_log(NULL, AV_LOG_ERROR,
               "SDL advised audio format %d is not supported!\n", spec.format);
        return -1;
    }
    if (spec.channels != wanted_spec.channels) {
        wanted_channel_layout = av_get_default_channel_layout(spec.channels);
        if (!wanted_channel_layout) {
            av_log(NULL, AV_LOG_ERROR,
                   "SDL advised channel count %d is not supported!\n", spec.channels);
            return -1;
        }
    }

    audio_hw_params->fmt = AV_SAMPLE_FMT_S16;
    audio_hw_params->freq = spec.freq;
    audio_hw_params->channel_layout = wanted_channel_layout;
    audio_hw_params->channels =  spec.channels;
    audio_hw_params->frame_size = av_samples_get_buffer_size(NULL, audio_hw_params->channels, 1, audio_hw_params->fmt, 1);
    audio_hw_params->bytes_per_sec = av_samples_get_buffer_size(NULL, audio_hw_params->channels, audio_hw_params->freq, audio_hw_params->fmt, 1);
    if (audio_hw_params->bytes_per_sec <= 0 || audio_hw_params->frame_size <= 0) {
        av_log(NULL, AV_LOG_ERROR, "av_samples_get_buffer_size failed\n");
        return -1;
    }
    return spec.size;
}

/* open a given stream. Return 0 if OK */
static int stream_component_open(VideoState *is, int stream_index)
{
    AVFormatContext *ic = is->ic;
    AVCodecContext *avctx;
    AVCodec *codec;
    const char *forced_codec_name = NULL;
    AVDictionary *opts = NULL;
    AVDictionaryEntry *t = NULL;
    int sample_rate, nb_channels;
    int64_t channel_layout;
    int ret = 0;
    int stream_lowres = lowres;

    if (stream_index < 0 || stream_index >= ic->nb_streams)
        return -1;

    avctx = avcodec_alloc_context3(NULL);
    if (!avctx)
        return AVERROR(ENOMEM);

    ret = avcodec_parameters_to_context(avctx, ic->streams[stream_index]->codecpar);
    if (ret < 0)
        goto fail;
    av_codec_set_pkt_timebase(avctx, ic->streams[stream_index]->time_base);

    codec = avcodec_find_decoder(avctx->codec_id);

    switch(avctx->codec_type){
        case AVMEDIA_TYPE_AUDIO   : is->last_audio_stream    = stream_index; forced_codec_name =    audio_codec_name; break;
        case AVMEDIA_TYPE_SUBTITLE: is->last_subtitle_stream = stream_index; forced_codec_name = subtitle_codec_name; break;
        case AVMEDIA_TYPE_VIDEO   : is->last_video_stream    = stream_index; forced_codec_name =    video_codec_name; break;
    }
    if (forced_codec_name)
        codec = avcodec_find_decoder_by_name(forced_codec_name);
    if (!codec) {
        if (forced_codec_name) av_log(NULL, AV_LOG_WARNING,
                                      "No codec could be found with name '%s'\n", forced_codec_name);
        else                   av_log(NULL, AV_LOG_WARNING,
                                      "No codec could be found with id %d\n", avctx->codec_id);
        ret = AVERROR(EINVAL);
        goto fail;
    }

    avctx->codec_id = codec->id;
    if(stream_lowres > av_codec_get_max_lowres(codec)){
        av_log(avctx, AV_LOG_WARNING, "The maximum value for lowres supported by the decoder is %d\n",
                av_codec_get_max_lowres(codec));
        stream_lowres = av_codec_get_max_lowres(codec);
    }
    av_codec_set_lowres(avctx, stream_lowres);

#if FF_API_EMU_EDGE
    if(stream_lowres) avctx->flags |= CODEC_FLAG_EMU_EDGE;
#endif
    if (fast)
        avctx->flags2 |= AV_CODEC_FLAG2_FAST;
#if FF_API_EMU_EDGE
    if(codec->capabilities & AV_CODEC_CAP_DR1)
        avctx->flags |= CODEC_FLAG_EMU_EDGE;
#endif

    opts = filter_codec_opts(codec_opts, avctx->codec_id, ic, ic->streams[stream_index], codec);
    if (!av_dict_get(opts, "threads", NULL, 0))
        av_dict_set(&opts, "threads", "auto", 0);
    if (stream_lowres)
        av_dict_set_int(&opts, "lowres", stream_lowres, 0);
    if (avctx->codec_type == AVMEDIA_TYPE_VIDEO || avctx->codec_type == AVMEDIA_TYPE_AUDIO)
        av_dict_set(&opts, "refcounted_frames", "1", 0);
    if ((ret = avcodec_open2(avctx, codec, &opts)) < 0) {
        goto fail;
    }
    if ((t = av_dict_get(opts, "", NULL, AV_DICT_IGNORE_SUFFIX))) {
        av_log(NULL, AV_LOG_ERROR, "Option %s not found.\n", t->key);
        ret =  AVERROR_OPTION_NOT_FOUND;
        goto fail;
    }

    is->eof = 0;
    ic->streams[stream_index]->discard = AVDISCARD_DEFAULT;
    switch (avctx->codec_type) {
    case AVMEDIA_TYPE_AUDIO:
#if CONFIG_AVFILTER
        {
            AVFilterLink *link;

            is->audio_filter_src.freq           = avctx->sample_rate;
            is->audio_filter_src.channels       = avctx->channels;
            is->audio_filter_src.channel_layout = get_valid_channel_layout(avctx->channel_layout, avctx->channels);
            is->audio_filter_src.fmt            = avctx->sample_fmt;
            if ((ret = configure_audio_filters(is, afilters, 0)) < 0)
                goto fail;
            link = is->out_audio_filter->inputs[0];
            sample_rate    = link->sample_rate;
            nb_channels    = avfilter_link_get_channels(link);
            channel_layout = link->channel_layout;
        }
#else
        sample_rate    = avctx->sample_rate;
        nb_channels    = avctx->channels;
        channel_layout = avctx->channel_layout;
#endif

        /* prepare audio output */
        if ((ret = audio_open(is, channel_layout, nb_channels, sample_rate, &is->audio_tgt)) < 0)
            goto fail;
        is->audio_hw_buf_size = ret;
        is->audio_src = is->audio_tgt;
        is->audio_buf_size  = 0;
        is->audio_buf_index = 0;

        /* init averaging filter */
        is->audio_diff_avg_coef  = exp(log(0.01) / AUDIO_DIFF_AVG_NB);
        is->audio_diff_avg_count = 0;
        /* since we do not have a precise anough audio FIFO fullness,
           we correct audio sync only if larger than this threshold */
        is->audio_diff_threshold = (double)(is->audio_hw_buf_size) / is->audio_tgt.bytes_per_sec;

        is->audio_stream = stream_index;
        is->audio_st = ic->streams[stream_index];

        decoder_init(&is->auddec, avctx, &is->audioq, is->continue_read_thread);
        if ((is->ic->iformat->flags & (AVFMT_NOBINSEARCH | AVFMT_NOGENSEARCH | AVFMT_NO_BYTE_SEEK)) && !is->ic->iformat->read_seek) {
            is->auddec.start_pts = is->audio_st->start_time;
            is->auddec.start_pts_tb = is->audio_st->time_base;
        }
        if ((ret = decoder_start(&is->auddec, audio_thread, is)) < 0)
            goto out;
        SDL_PauseAudio(0);
        break;
    case AVMEDIA_TYPE_VIDEO:
        is->video_stream = stream_index;
        is->video_st = ic->streams[stream_index];

        is->viddec_width  = avctx->width;
        is->viddec_height = avctx->height;
        is->vert_split_pos = avctx->width / 2;
        is->last_vert_split_pos = is->vert_split_pos;
        is->mov_speed = 0; //avctx->width / 200;
        is->bk_data[0] = av_malloc(avctx->width * avctx->height);
        is->bk_data[1] = av_malloc(avctx->width * avctx->height / 4);
        is->bk_data[2] = av_malloc(avctx->width * avctx->height / 4);
        is->linesize[0] = avctx->width;
        is->linesize[1] = avctx->width / 2;
        is->linesize[2] = avctx->width / 2;

        decoder_init(&is->viddec, avctx, &is->videoq, is->continue_read_thread);
        if ((ret = decoder_start(&is->viddec, video_thread, is)) < 0)
            goto out;
        is->queue_attachments_req = 1;
        break;
    case AVMEDIA_TYPE_SUBTITLE:
        is->subtitle_stream = stream_index;
        is->subtitle_st = ic->streams[stream_index];

        decoder_init(&is->subdec, avctx, &is->subtitleq, is->continue_read_thread);
        if ((ret = decoder_start(&is->subdec, subtitle_thread, is)) < 0)
            goto out;
        break;
    default:
        break;
    }
    goto out;

fail:
    avcodec_free_context(&avctx);
out:
    av_dict_free(&opts);

    return ret;
}

static int decode_interrupt_cb(void *ctx)
{
    VideoState *is = ctx;
    return is->abort_request;
}

static int stream_has_enough_packets(AVStream *st, int stream_id, PacketQueue *queue) {
    return stream_id < 0 ||
           queue->abort_request ||
           (st->disposition & AV_DISPOSITION_ATTACHED_PIC) ||
           queue->nb_packets > MIN_FRAMES && (!queue->duration || av_q2d(st->time_base) * queue->duration > 1.0);
}

static int is_realtime(AVFormatContext *s)
{
    if(   !strcmp(s->iformat->name, "rtp")
       || !strcmp(s->iformat->name, "rtsp")
       || !strcmp(s->iformat->name, "sdp")
    )
        return 1;

    if(s->pb && (   !strncmp(s->filename, "rtp:", 4)
                 || !strncmp(s->filename, "udp:", 4)
                )
    )
        return 1;
    return 0;
}

/* this thread gets the stream from the disk or the network */
static int read_thread(void *arg)
{
    VideoState *is = arg;
    AVFormatContext *ic = NULL;
    int err, i, ret;
    int st_index[AVMEDIA_TYPE_NB];
    AVPacket pkt1, *pkt = &pkt1;
    int64_t stream_start_time;
    int pkt_in_play_range = 0;
    AVDictionaryEntry *t;
    AVDictionary **opts;
    int orig_nb_streams;
    SDL_mutex *wait_mutex = SDL_CreateMutex();
    int scan_all_pmts_set = 0;
    int64_t pkt_ts;

    if (!wait_mutex) {
        av_log(NULL, AV_LOG_FATAL, "SDL_CreateMutex(): %s\n", SDL_GetError());
        ret = AVERROR(ENOMEM);
        goto fail;
    }

    memset(st_index, -1, sizeof(st_index));
    is->last_video_stream = is->video_stream = -1;
    is->last_audio_stream = is->audio_stream = -1;
    is->last_subtitle_stream = is->subtitle_stream = -1;
    is->eof = 0;

    ic = avformat_alloc_context();
    if (!ic) {
        av_log(NULL, AV_LOG_FATAL, "Could not allocate context.\n");
        ret = AVERROR(ENOMEM);
        goto fail;
    }
    ic->interrupt_callback.callback = decode_interrupt_cb;
    ic->interrupt_callback.opaque = is;
    //if (!av_dict_get(format_opts, "scan_all_pmts", NULL, AV_DICT_MATCH_CASE)) {
    //    av_dict_set(&format_opts, "scan_all_pmts", "1", AV_DICT_DONT_OVERWRITE);
    //    scan_all_pmts_set = 1;
    //}
    err = avformat_open_input(&ic, is->filename, is->iformat, &format_opts);

    if (err < 0) {
        print_error(is->filename, err);
        ret = -1;
        goto fail;
    }
    
    //if (scan_all_pmts_set)
    //    av_dict_set(&format_opts, "scan_all_pmts", NULL, AV_DICT_MATCH_CASE);

    //if ((t = av_dict_get(format_opts, "", NULL, AV_DICT_IGNORE_SUFFIX))) {
    //    av_log(NULL, AV_LOG_ERROR, "Option %s not found.\n", t->key);
    //    ret = AVERROR_OPTION_NOT_FOUND;
    //    goto fail;
    //}
    is->ic = ic;

    if (genpts)
        ic->flags |= AVFMT_FLAG_GENPTS;

    av_format_inject_global_side_data(ic);

    opts = setup_find_stream_info_opts(ic, codec_opts);
    orig_nb_streams = ic->nb_streams;

    err = avformat_find_stream_info(ic, opts);
    
    for (i = 0; i < orig_nb_streams; i++)
        av_dict_free(&opts[i]);
    av_freep(&opts);

    if (err < 0) {
        av_log(NULL, AV_LOG_WARNING,
               "%s: could not find codec parameters\n", is->filename);
        ret = -1;
        goto fail;
    }

    if (ic->pb)
        ic->pb->eof_reached = 0; // FIXME hack, ffplay maybe should not use avio_feof() to test for the end

    if (seek_by_bytes < 0)
        seek_by_bytes = !!(ic->iformat->flags & AVFMT_TS_DISCONT) && strcmp("ogg", ic->iformat->name);

    is->max_frame_duration = (ic->iformat->flags & AVFMT_TS_DISCONT) ? 10.0 : 3600.0;

    if (!window_title && (t = av_dict_get(ic->metadata, "title", NULL, 0)))
        window_title = av_asprintf("%s - %s", t->value, input_filename[0]);

    /* if seeking requested, we execute it */
    if (start_time != AV_NOPTS_VALUE) {
        int64_t timestamp;

        timestamp = start_time;
        /* add the stream start time */
        if (ic->start_time != AV_NOPTS_VALUE)
            timestamp += ic->start_time;
        ret = avformat_seek_file(ic, -1, INT64_MIN, timestamp, INT64_MAX, 0);
        if (ret < 0) {
            av_log(NULL, AV_LOG_WARNING, "%s: could not seek to position %0.3f\n",
                    is->filename, (double)timestamp / AV_TIME_BASE);
        }
    }

    is->realtime = is_realtime(ic);

    if (show_status)
        av_dump_format(ic, 0, is->filename, 0);

    for (i = 0; i < ic->nb_streams; i++) {
        AVStream *st = ic->streams[i];
        enum AVMediaType type = st->codecpar->codec_type;
        st->discard = AVDISCARD_ALL;
        if (wanted_stream_spec[type] && st_index[type] == -1)
            if (avformat_match_stream_specifier(ic, st, wanted_stream_spec[type]) > 0)
                st_index[type] = i;
    }
    for (i = 0; i < AVMEDIA_TYPE_NB; i++) {
        if (wanted_stream_spec[i] && st_index[i] == -1) {
            av_log(NULL, AV_LOG_ERROR, "Stream specifier %s does not match any %s stream\n", wanted_stream_spec[i], av_get_media_type_string(i));
            st_index[i] = INT_MAX;
        }
    }

    if (!video_disable)
        st_index[AVMEDIA_TYPE_VIDEO] =
            av_find_best_stream(ic, AVMEDIA_TYPE_VIDEO,
                                st_index[AVMEDIA_TYPE_VIDEO], -1, NULL, 0);
    if (!audio_disable)
        st_index[AVMEDIA_TYPE_AUDIO] =
            av_find_best_stream(ic, AVMEDIA_TYPE_AUDIO,
                                st_index[AVMEDIA_TYPE_AUDIO],
                                st_index[AVMEDIA_TYPE_VIDEO],
                                NULL, 0);
    if (!video_disable && !subtitle_disable)
        st_index[AVMEDIA_TYPE_SUBTITLE] =
            av_find_best_stream(ic, AVMEDIA_TYPE_SUBTITLE,
                                st_index[AVMEDIA_TYPE_SUBTITLE],
                                (st_index[AVMEDIA_TYPE_AUDIO] >= 0 ?
                                 st_index[AVMEDIA_TYPE_AUDIO] :
                                 st_index[AVMEDIA_TYPE_VIDEO]),
                                NULL, 0);

    is->show_mode = show_mode;
    if (st_index[AVMEDIA_TYPE_VIDEO] >= 0) {
        AVStream *st = ic->streams[st_index[AVMEDIA_TYPE_VIDEO]];
        AVCodecParameters *codecpar = st->codecpar;
        AVRational sar = av_guess_sample_aspect_ratio(ic, st, NULL);
        if (codecpar->width)
            set_default_window_size(codecpar->width, codecpar->height, sar);
    }

    /* open the streams */
    if (st_index[AVMEDIA_TYPE_AUDIO] >= 0) {
        stream_component_open(is, st_index[AVMEDIA_TYPE_AUDIO]);
    }

    ret = -1;
    if (st_index[AVMEDIA_TYPE_VIDEO] >= 0) {
        ret = stream_component_open(is, st_index[AVMEDIA_TYPE_VIDEO]);
    }
    if (is->show_mode == SHOW_MODE_NONE)
        is->show_mode = ret >= 0 ? SHOW_MODE_VIDEO : SHOW_MODE_RDFT;

    if (st_index[AVMEDIA_TYPE_SUBTITLE] >= 0) {
        stream_component_open(is, st_index[AVMEDIA_TYPE_SUBTITLE]);
    }

    if (is->video_stream < 0 && is->audio_stream < 0) {
        av_log(NULL, AV_LOG_FATAL, "Failed to open file '%s' or configure filtergraph\n",
               is->filename);
        ret = -1;
        goto fail;
    }

    if (infinite_buffer < 0 && is->realtime)
        infinite_buffer = 1;

    for (;;) {
        if (is->abort_request)
            break;
        if (is->paused != is->last_paused) {
            is->last_paused = is->paused;
            if (is->paused)
                is->read_pause_return = av_read_pause(ic);
            else
                av_read_play(ic);
        }
#if CONFIG_RTSP_DEMUXER || CONFIG_MMSH_PROTOCOL
        if (is->paused &&
                (!strcmp(ic->iformat->name, "rtsp") ||
                 (ic->pb && !strncmp(input_filename[0], "mmsh:", 5)))) {
            /* wait 10 ms to avoid trying to get another packet */
            /* XXX: horrible */
            SDL_Delay(10);
            continue;
        }
#endif 
        if (is->seek_req) {
            int64_t seek_target = is->seek_pos;
            int64_t seek_min    = is->seek_rel > 0 ? seek_target - is->seek_rel + 2: INT64_MIN;
            int64_t seek_max    = is->seek_rel < 0 ? seek_target - is->seek_rel - 2: INT64_MAX;
// FIXME the +-2 is due to rounding being not done in the correct direction in generation
//      of the seek_pos/seek_rel variables

            ret = avformat_seek_file(is->ic, -1, seek_min, seek_target, seek_max, is->seek_flags);
            //av_log(NULL, AV_LOG_FATAL, "%s seek to %lld\n", is->ic->filename , seek_target);
            if (ret < 0) {
                av_log(NULL, AV_LOG_ERROR,
                       "%s: error while seeking\n", is->ic->filename);
            } else {
                if (is->audio_stream >= 0) {
                    packet_queue_flush(&is->audioq);
                    packet_queue_put(&is->audioq, &flush_pkt);
                }
                if (is->subtitle_stream >= 0) {
                    packet_queue_flush(&is->subtitleq);
                    packet_queue_put(&is->subtitleq, &flush_pkt);
                }
                if (is->video_stream >= 0) {
                    packet_queue_flush(&is->videoq);
                    packet_queue_put(&is->videoq, &flush_pkt);
                }
                if (is->seek_flags & AVSEEK_FLAG_BYTE) {
                   set_clock(&is->extclk, NAN, 0);
                } else {
                   set_clock(&is->extclk, seek_target / (double)AV_TIME_BASE, 0);
                }
            }
            is->seek_req = 0;
            is->queue_attachments_req = 1;
            is->eof = 0;
            if (is->paused)
                step_to_next_frame(is);
        }
        if (is->queue_attachments_req) {
            if (is->video_st && is->video_st->disposition & AV_DISPOSITION_ATTACHED_PIC) {
                AVPacket copy;
                if ((ret = av_copy_packet(&copy, &is->video_st->attached_pic)) < 0)
                    goto fail;
                packet_queue_put(&is->videoq, &copy);
                packet_queue_put_nullpacket(&is->videoq, is->video_stream);
            }
            is->queue_attachments_req = 0;
        }

        /* if the queue are full, no need to read more */
        if (infinite_buffer<1 &&
              (is->audioq.size + is->videoq.size + is->subtitleq.size > MAX_QUEUE_SIZE
            || (stream_has_enough_packets(is->audio_st, is->audio_stream, &is->audioq) &&
                stream_has_enough_packets(is->video_st, is->video_stream, &is->videoq) &&
                stream_has_enough_packets(is->subtitle_st, is->subtitle_stream, &is->subtitleq)))) {
            /* wait 10 ms */
            SDL_LockMutex(wait_mutex);
            SDL_CondWaitTimeout(is->continue_read_thread, wait_mutex, 10);
            SDL_UnlockMutex(wait_mutex);
            continue;
        }
        if (!is->paused &&
            (!is->audio_st || (is->auddec.finished == is->audioq.serial && frame_queue_nb_remaining(&is->sampq) == 0)) &&
            (!is->video_st || (is->viddec.finished == is->videoq.serial && frame_queue_nb_remaining(&is->pictq) == 0))) {
            if (loop != 1 && (!loop || --loop)) {
                stream_seek(is, start_time != AV_NOPTS_VALUE ? start_time : 0, 0, 0);
            } else if (autoexit) {
                ret = AVERROR_EOF;
                goto fail;
            }
        }
        ret = av_read_frame(ic, pkt);
        if (ret < 0) {
            if ((ret == AVERROR_EOF || avio_feof(ic->pb)) && !is->eof) {
                if (is->video_stream >= 0)
                    packet_queue_put_nullpacket(&is->videoq, is->video_stream);
                if (is->audio_stream >= 0)
                    packet_queue_put_nullpacket(&is->audioq, is->audio_stream);
                if (is->subtitle_stream >= 0)
                    packet_queue_put_nullpacket(&is->subtitleq, is->subtitle_stream);
                is->eof = 1;
            }
            if (ic->pb && ic->pb->error)
                break;
            SDL_LockMutex(wait_mutex);
            SDL_CondWaitTimeout(is->continue_read_thread, wait_mutex, 10);
            SDL_UnlockMutex(wait_mutex);
            continue;
        } else {
            is->eof = 0;
        }
        /* check if packet is in play range specified by user, then queue, otherwise discard */
        stream_start_time = ic->streams[pkt->stream_index]->start_time;
        pkt_ts = pkt->pts == AV_NOPTS_VALUE ? pkt->dts : pkt->pts;
        pkt_in_play_range = duration == AV_NOPTS_VALUE ||
                (pkt_ts - (stream_start_time != AV_NOPTS_VALUE ? stream_start_time : 0)) *
                av_q2d(ic->streams[pkt->stream_index]->time_base) -
                (double)(start_time != AV_NOPTS_VALUE ? start_time : 0) / 1000000
                <= ((double)duration / 1000000);
        if (pkt->stream_index == is->audio_stream && pkt_in_play_range) {
            packet_queue_put(&is->audioq, pkt);
        } else if (pkt->stream_index == is->video_stream && pkt_in_play_range
                   && !(is->video_st->disposition & AV_DISPOSITION_ATTACHED_PIC)) {
            packet_queue_put(&is->videoq, pkt);
        } else if (pkt->stream_index == is->subtitle_stream && pkt_in_play_range) {
            packet_queue_put(&is->subtitleq, pkt);
        } else {
            av_packet_unref(pkt);
        }
    }

    ret = 0;
 fail:
    if (ic && !is->ic)
        avformat_close_input(&ic);

    if (ret != 0) {
        SDL_Event event;

        event.type = FF_QUIT_EVENT;
        event.user.data1 = is;
        SDL_PushEvent(&event);
    }
    SDL_DestroyMutex(wait_mutex);
    return 0;
}

static VideoState *stream_open(const char *filename, AVInputFormat *iformat)
{
    VideoState *is;

    is = av_mallocz(sizeof(VideoState));
    if (!is)
        return NULL;
    is->filename = av_strdup(filename);
    if (!is->filename)
        goto fail;
    is->iformat = iformat;
    is->ytop    = 0;
    is->xleft   = 0;
    is->first_pts = -1;

    /* start video display */
    if (frame_queue_init(&is->pictq, &is->videoq, VIDEO_PICTURE_QUEUE_SIZE, 1) < 0)
        goto fail;
    if (frame_queue_init(&is->subpq, &is->subtitleq, SUBPICTURE_QUEUE_SIZE, 0) < 0)
        goto fail;
    if (frame_queue_init(&is->sampq, &is->audioq, SAMPLE_QUEUE_SIZE, 1) < 0)
        goto fail;

    if (packet_queue_init(&is->videoq) < 0 ||
        packet_queue_init(&is->audioq) < 0 ||
        packet_queue_init(&is->subtitleq) < 0)
        goto fail;

    if (!(is->continue_read_thread = SDL_CreateCond())) {
        av_log(NULL, AV_LOG_FATAL, "SDL_CreateCond(): %s\n", SDL_GetError());
        goto fail;
    }

    init_clock(&is->vidclk, &is->videoq.serial);
    init_clock(&is->audclk, &is->audioq.serial);
    init_clock(&is->extclk, &is->extclk.serial);
    is->audio_clock_serial = -1;
    is->audio_volume = SDL_MIX_MAXVOLUME;
    is->muted = 0;
    is->av_sync_type = av_sync_type;
    is->read_tid     = SDL_CreateThread(read_thread, is);
    if (!is->read_tid) {
        av_log(NULL, AV_LOG_FATAL, "SDL_CreateThread(): %s\n", SDL_GetError());
fail:
        stream_close(is);
        return NULL;
    }
    return is;
}

static void stream_cycle_channel(VideoState *is, int codec_type)
{
    AVFormatContext *ic = is->ic;
    int start_index, stream_index;
    int old_index;
    AVStream *st;
    AVProgram *p = NULL;
    int nb_streams = is->ic->nb_streams;

    if (codec_type == AVMEDIA_TYPE_VIDEO) {
        start_index = is->last_video_stream;
        old_index = is->video_stream;
    } else if (codec_type == AVMEDIA_TYPE_AUDIO) {
        start_index = is->last_audio_stream;
        old_index = is->audio_stream;
    } else {
        start_index = is->last_subtitle_stream;
        old_index = is->subtitle_stream;
    }
    stream_index = start_index;

    if (codec_type != AVMEDIA_TYPE_VIDEO && is->video_stream != -1) {
        p = av_find_program_from_stream(ic, NULL, is->video_stream);
        if (p) {
            nb_streams = p->nb_stream_indexes;
            for (start_index = 0; start_index < nb_streams; start_index++)
                if (p->stream_index[start_index] == stream_index)
                    break;
            if (start_index == nb_streams)
                start_index = -1;
            stream_index = start_index;
        }
    }

    for (;;) {
        if (++stream_index >= nb_streams)
        {
            if (codec_type == AVMEDIA_TYPE_SUBTITLE)
            {
                stream_index = -1;
                is->last_subtitle_stream = -1;
                goto the_end;
            }
            if (start_index == -1)
                return;
            stream_index = 0;
        }
        if (stream_index == start_index)
            return;
        st = is->ic->streams[p ? p->stream_index[stream_index] : stream_index];
        if (st->codecpar->codec_type == codec_type) {
            /* check that parameters are OK */
            switch (codec_type) {
            case AVMEDIA_TYPE_AUDIO:
                if (st->codecpar->sample_rate != 0 &&
                    st->codecpar->channels != 0)
                    goto the_end;
                break;
            case AVMEDIA_TYPE_VIDEO:
            case AVMEDIA_TYPE_SUBTITLE:
                goto the_end;
            default:
                break;
            }
        }
    }
 the_end:
    if (p && stream_index != -1)
        stream_index = p->stream_index[stream_index];
    av_log(NULL, AV_LOG_INFO, "Switch %s stream from #%d to #%d\n",
           av_get_media_type_string(codec_type),
           old_index,
           stream_index);

    stream_component_close(is, old_index);
    stream_component_open(is, stream_index);
}


static void toggle_full_screen(VideoState *is)
{
#if defined(__APPLE__) && SDL_VERSION_ATLEAST(1, 2, 14)
    /* OS X needs to reallocate the SDL overlays */
    int i;
    for (i = 0; i < VIDEO_PICTURE_QUEUE_SIZE; i++)
        is->pictq.queue[i].reallocate = 1;
#endif
    is_full_screen = !is_full_screen;
    video_open(is, 1, NULL);
}

static void toggle_audio_display(VideoState *is)
{
    int bgcolor = SDL_MapRGB(screen->format, 0x00, 0x00, 0x00);
    int next = is->show_mode;
    do {
        next = (next + 1) % SHOW_MODE_NB;
    } while (next != is->show_mode && (next == SHOW_MODE_VIDEO && !is->video_st || next != SHOW_MODE_VIDEO && !is->audio_st));
    if (is->show_mode != next) {
        fill_rectangle(screen,
                    is->xleft, is->ytop, is->width, is->height,
                    bgcolor, 1);
        is->force_refresh = 1;
        is->show_mode = next;
    }
}

static void refresh_loop_wait_event(VideoState *is, VideoState *aux_is, SDL_Event *event) {
    double remaining_time = 0.0;
    SDL_PumpEvents(); // Pumps the event loop, gathering events from the input devices.
    while (!SDL_PeepEvents(event, 1, SDL_GETEVENT, SDL_ALLEVENTS)) { // Checks the event queue for messages and optionally returns them, SDL_GETEVENT means up to numevents events at the front of the event queue, matchingmask, will be returned and will be removed from the queue.
        // 如果事件队列中一直没有事件，则一直在此loop中，持续更新显示帧
        if (!cursor_hidden && av_gettime_relative() - cursor_last_shown > CURSOR_HIDE_DELAY) {
            SDL_ShowCursor(0);  // hide cursor after 1 seconds
            cursor_hidden = 1;
        }
        if (remaining_time > 0.0)
            av_usleep((int64_t)(remaining_time * 1000000.0));
        remaining_time = REFRESH_RATE;
        if (is->show_mode != SHOW_MODE_NONE && (!is->paused || is->force_refresh))
            video_refresh(is, aux_is, &remaining_time); // return remaining_time for synchronization
        SDL_PumpEvents();
    }
}

static void seek_chapter(VideoState *is, int incr)
{
    int64_t pos = get_master_clock(is) * AV_TIME_BASE;
    int i;

    if (!is->ic->nb_chapters)
        return;

    /* find the current chapter */
    for (i = 0; i < is->ic->nb_chapters; i++) {
        AVChapter *ch = is->ic->chapters[i];
        if (av_compare_ts(pos, AV_TIME_BASE_Q, ch->start, ch->time_base) < 0) {
            i--;
            break;
        }
    }

    i += incr;
    i = FFMAX(i, 0);
    if (i >= is->ic->nb_chapters)
        return;

    av_log(NULL, AV_LOG_VERBOSE, "Seeking to chapter %d.\n", i);
    stream_seek(is, av_rescale_q(is->ic->chapters[i]->start, is->ic->chapters[i]->time_base,
                                 AV_TIME_BASE_Q), 0, 0);
}

/* handle an event sent by the GUI */
static void event_loop(VideoState *cur_stream, VideoState *auxlilary_stream)
{
    SDL_Event event;
    double incr, pos, frac;
    int mouse_action = 0; // 0 - seek, 1 - reset vert split position; other value - do nothing
    Frame *vp, *lastvp, *auxvp, *auxlastvp;
    cur_stream->left_mouse_bt_stat = 0; // button up
    cur_stream->delay_frame_num = 0;
    if(auxlilary_stream)
        auxlilary_stream->delay_frame_num = 0;
    
    for (;;) {
        double x;
        refresh_loop_wait_event(cur_stream, auxlilary_stream, &event);
        switch (event.type) {
        case SDL_KEYDOWN:
            if (exit_on_keydown) {
                do_exit(cur_stream);
                if(auxlilary_stream) // free auxlilary stream
                    do_exit(cur_stream);
                break;
            }
            switch (event.key.keysym.sym) {
            case SDLK_ESCAPE:
            case SDLK_q:
                do_exit(cur_stream);
                if(auxlilary_stream) // free auxlilary stream
                    do_exit(cur_stream);
                break;
            case SDLK_f:
                toggle_full_screen(cur_stream);
                cur_stream->force_refresh = 1;
                break;
            case SDLK_p:
            case SDLK_SPACE:
                toggle_pause(cur_stream);
                if(auxlilary_stream)
                {
                    double last_duration = 0.0, aux_duration = 0.0;
                    double auxvp_rela_pts;
                    double vp_rela_pts; 
                    toggle_pause(auxlilary_stream); // need to synchronize two streams
                    av_usleep((int64_t)(0.100 * 1000000.0)); // sleep 100ms, wait until pause operation finished, then continue synchronize two streams
                     
                    // continue synchronize two streams
                    lastvp = frame_queue_peek_last(&cur_stream->pictq);
                    vp = frame_queue_peek(&cur_stream->pictq);
                    last_duration = vp_duration(cur_stream, lastvp, vp);
                    auxvp = frame_queue_peek(&auxlilary_stream->pictq);
                    auxlastvp = frame_queue_peek_last(&auxlilary_stream->pictq);
                    aux_duration = vp_duration(auxlilary_stream, auxlastvp, auxvp);
                    while(cur_stream->paused) // current stat is paused, need to synchronize
                    {
                        vp    = frame_queue_peek(&cur_stream->pictq);
                        auxvp = frame_queue_peek(&auxlilary_stream->pictq);
                        if(auxlilary_stream->first_pts >= 0 && cur_stream->delay_frame_num >= 0)
                        {
                            auxvp_rela_pts = auxvp->pts - auxlilary_stream->first_pts + auxlilary_stream->delay_frame_num * aux_duration;
                            vp_rela_pts = vp->pts - cur_stream->first_pts + cur_stream->delay_frame_num * last_duration; 
                            if(auxvp_rela_pts <= vp_rela_pts - 0.999 * aux_duration) // aux stream is slower than main stream
                            {
                                if (frame_queue_nb_remaining(&auxlilary_stream->pictq) > 1)
                                    frame_queue_next(&auxlilary_stream->pictq);  // move to next frame
                            }
                            else if(auxvp_rela_pts >= vp_rela_pts + aux_duration)  // aux stream is faster than main stream
                            {
                                 if (frame_queue_nb_remaining(&cur_stream->pictq) > 1)
                                    frame_queue_next(&cur_stream->pictq);  // move to next frame
                            }
                            else if(auxvp_rela_pts < vp_rela_pts + 0.999 * aux_duration) // aux stream is sychronized with main stream
                            {
                                //av_log(NULL, AV_LOG_INFO, "sync while paused: pts = %f, aux_pts = %f, aux_duration = %f, %f\n", vp_rela_pts, auxvp_rela_pts, aux_duration, vp_rela_pts + 0.999 * aux_duration);
                                break;
                            } 
                        }
                        else
                        {
                            if(auxvp->dec_frame_num + auxlilary_stream->delay_frame_num < vp->dec_frame_num + cur_stream->delay_frame_num)// aux stream is slower than main stream
                            {
                                if (frame_queue_nb_remaining(&auxlilary_stream->pictq) > 1)
                                    frame_queue_next(&auxlilary_stream->pictq);  // move to next frame
                            }
                            else if(auxvp->dec_frame_num + auxlilary_stream->delay_frame_num > vp->dec_frame_num + cur_stream->delay_frame_num)// aux stream is faster than main stream
                            {
                                if (frame_queue_nb_remaining(&cur_stream->pictq) > 1)
                                    frame_queue_next(&cur_stream->pictq);  // move to next frame
                            }
                            else
                                break;
                        }
                    }
                    //vp    = frame_queue_peek(&cur_stream->pictq);
                    //auxvp = frame_queue_peek(&auxlilary_stream->pictq);
                    //auxvp_rela_pts = auxvp->pts - auxlilary_stream->first_pts + auxlilary_stream->delay_frame_num * aux_duration;
                    //vp_rela_pts = vp->pts - cur_stream->first_pts + cur_stream->delay_frame_num * last_duration; 
                    //av_log(NULL, AV_LOG_FATAL, "pts = %f, aux_pts = %f, diff_threshold = %f\n", vp_rela_pts, auxvp_rela_pts, aux_duration);
                    video_display(cur_stream, auxlilary_stream);
                }

                break;
            case SDLK_m:
                toggle_mute(cur_stream);
                break;
            case SDLK_KP_MULTIPLY:
            case SDLK_0:
                update_volume(cur_stream, 1, SDL_VOLUME_STEP);
                break;
            case SDLK_KP_DIVIDE:
            case SDLK_9:
                update_volume(cur_stream, -1, SDL_VOLUME_STEP);
                break;
            case SDLK_s: // S: Step to next frame
                step_to_next_frame(cur_stream);
                if(auxlilary_stream)
                    step_to_next_frame(auxlilary_stream);
                break;
            case SDLK_F1:
                if(auxlilary_stream)
                    auxlilary_stream->delay_frame_num++;
                cur_stream->step = 1;
                if (frame_queue_nb_remaining(&cur_stream->pictq) > 1)
                    frame_queue_next(&cur_stream->pictq);
                
                vp = frame_queue_peek_last(&cur_stream->pictq);
                if(vp->bmp) // need to backup as main_stream has refreshed 
                {
                    int i;
                    for(i = 0; i < vp->height; i++)
                        memcpy(cur_stream->bk_data[0] + i * vp->width, vp->bmp->pixels[0] + i * vp->bmp->pitches[0], vp->width);
                    for(i = 0; i < vp->height / 2; i++)
                    {
                        memcpy(cur_stream->bk_data[1] + i * vp->width / 2, vp->bmp->pixels[1] + i * vp->bmp->pitches[1], vp->width / 2);
                        memcpy(cur_stream->bk_data[2] + i * vp->width / 2, vp->bmp->pixels[2] + i * vp->bmp->pitches[2], vp->width / 2);
                    }
                }
                video_display(cur_stream, auxlilary_stream);
                break;   
            case SDLK_F2:
                cur_stream->step = 1;
                cur_stream->delay_frame_num++;
                if (auxlilary_stream && frame_queue_nb_remaining(&auxlilary_stream->pictq) > 1)
                    frame_queue_next(&auxlilary_stream->pictq);
                video_display(cur_stream, auxlilary_stream);
                break; 
            case SDLK_a:
                stream_cycle_channel(cur_stream, AVMEDIA_TYPE_AUDIO);
                break;
            case SDLK_v:
                stream_cycle_channel(cur_stream, AVMEDIA_TYPE_VIDEO);
                break;
            case SDLK_c:
                stream_cycle_channel(cur_stream, AVMEDIA_TYPE_VIDEO);
                stream_cycle_channel(cur_stream, AVMEDIA_TYPE_AUDIO);
                stream_cycle_channel(cur_stream, AVMEDIA_TYPE_SUBTITLE);
                break;
            case SDLK_t:
                stream_cycle_channel(cur_stream, AVMEDIA_TYPE_SUBTITLE);
                break;
            case SDLK_w:
#if CONFIG_AVFILTER
                if (cur_stream->show_mode == SHOW_MODE_VIDEO && cur_stream->vfilter_idx < nb_vfilters - 1) {
                    if (++cur_stream->vfilter_idx >= nb_vfilters)
                        cur_stream->vfilter_idx = 0;
                } else {
                    cur_stream->vfilter_idx = 0;
                    toggle_audio_display(cur_stream);
                }
#else
                toggle_audio_display(cur_stream);
#endif
                break;
            case SDLK_PAGEUP:
                if (cur_stream->ic->nb_chapters <= 1) {
                    incr = 600.0;
                    goto do_seek;
                }
                seek_chapter(cur_stream, 1);
                break;
            case SDLK_PAGEDOWN:
                if (cur_stream->ic->nb_chapters <= 1) {
                    incr = -600.0;
                    goto do_seek;
                }
                seek_chapter(cur_stream, -1);
                break;
            case SDLK_LEFT:
                incr = -10.0;
                goto do_seek;
            case SDLK_RIGHT:
                incr = 10.0;
                goto do_seek;
            case SDLK_UP:
                incr = 60.0;
                goto do_seek;
            case SDLK_DOWN:
                incr = -60.0;
            do_seek:
                //printf("seek may not supported well yet\n");
                //break;
                    if (seek_by_bytes) {
                        int bkincr = incr;
                        pos = -1;
                        if (pos < 0 && cur_stream->video_stream >= 0)
                            pos = frame_queue_last_pos(&cur_stream->pictq);
                        if (pos < 0 && cur_stream->audio_stream >= 0)
                            pos = frame_queue_last_pos(&cur_stream->sampq);
                        if (pos < 0)
                            pos = avio_tell(cur_stream->ic->pb);
                        if (cur_stream->ic->bit_rate)
                            incr *= cur_stream->ic->bit_rate / 8.0;
                        else
                            incr *= 180000.0;
                        pos += incr;
                        stream_seek(cur_stream, pos, incr, 1);
                        
                        if(auxlilary_stream)
                        {
                            incr = bkincr;
                            pos = -1;
                            if (pos < 0 && auxlilary_stream->video_stream >= 0)
                                pos = frame_queue_last_pos(&auxlilary_stream->pictq);
                            if (pos < 0 && auxlilary_stream->audio_stream >= 0)
                                pos = frame_queue_last_pos(&auxlilary_stream->sampq);
                            if (pos < 0)
                                pos = avio_tell(auxlilary_stream->ic->pb);
                            if (auxlilary_stream->ic->bit_rate)
                                incr *= auxlilary_stream->ic->bit_rate / 8.0;
                            else
                                incr *= 180000.0;
                            pos += incr;
                            stream_seek(auxlilary_stream, pos, incr, 1);
                        }

                    } else {
                        pos = get_master_clock(cur_stream);
                        if (isnan(pos))
                            pos = (double)cur_stream->seek_pos / AV_TIME_BASE;
                        pos += incr;
                        if (cur_stream->ic->start_time != AV_NOPTS_VALUE && pos < cur_stream->ic->start_time / (double)AV_TIME_BASE)
                            pos = cur_stream->ic->start_time / (double)AV_TIME_BASE;
                        stream_seek(cur_stream, (int64_t)(pos * AV_TIME_BASE), (int64_t)(incr * AV_TIME_BASE), 0);
                        if(auxlilary_stream)
                            stream_seek(auxlilary_stream, (int64_t)(pos * AV_TIME_BASE), (int64_t)(incr * AV_TIME_BASE), 0);
                    }
                break;
            default:
                break;
            }
            break;
        case SDL_VIDEOEXPOSE:
            cur_stream->force_refresh = 1;
            break;
        case SDL_MOUSEBUTTONUP:
            if (event.button.button == SDL_BUTTON_LEFT)
            {
                cur_stream->left_mouse_bt_stat = 0; // record left mouse button stat
                break;
            }
        case SDL_MOUSEBUTTONDOWN:
            if (exit_on_mousedown) {
                do_exit(cur_stream);
                break;
            }
            if (event.button.button == SDL_BUTTON_LEFT) {
                cur_stream->left_mouse_bt_stat = 1;
                //static int64_t last_mouse_left_click = 0;
                //if (av_gettime_relative() - last_mouse_left_click <= 500000) {
                //    toggle_full_screen(cur_stream);
                //    cur_stream->force_refresh = 1;
                //    last_mouse_left_click = 0;
                //} else {
                //    last_mouse_left_click = av_gettime_relative();
                //}
            }
        case SDL_MOUSEMOTION:
            if (cursor_hidden) {
                SDL_ShowCursor(1);
                cursor_hidden = 0;
            }
            cursor_last_shown = av_gettime_relative();
            if (event.type == SDL_MOUSEBUTTONDOWN) {
                if (event.button.button != SDL_BUTTON_RIGHT)
                    mouse_action = 1;
                else
                    mouse_action = 0;
                x = event.button.x;
            } else {
                //if (!(event.motion.state & SDL_BUTTON_RMASK))
                //    break;
                if(cur_stream->left_mouse_bt_stat == 1)
                    mouse_action = 1;  // if left mouse button down and mouse move, then move the vertical split line
                else
                    mouse_action = -1;  // do nothing
                x = event.motion.x;
            }
            if(mouse_action == 0) // proceed seek mouse_action
            {
                //printf("seek not supported yet\n");
                //break;
                if (seek_by_bytes || cur_stream->ic->duration <= 0) {
                    uint64_t size =  avio_size(cur_stream->ic->pb);
                    stream_seek(cur_stream, size*x/cur_stream->width, 0, 1);
                    if(auxlilary_stream)
                    {
                        size =  avio_size(auxlilary_stream->ic->pb);
                        stream_seek(auxlilary_stream, size*x/auxlilary_stream->width, 0, 1);   
                    }
                } else {
                    int64_t ts;
                    int ns, hh, mm, ss;
                    int tns, thh, tmm, tss;
                    tns  = cur_stream->ic->duration / 1000000LL;
                    thh  = tns / 3600;
                    tmm  = (tns % 3600) / 60;
                    tss  = (tns % 60);
                    frac = x / cur_stream->width;
                    ns   = frac * tns;
                    hh   = ns / 3600;
                    mm   = (ns % 3600) / 60;
                    ss   = (ns % 60);
                    av_log(NULL, AV_LOG_INFO,
                           "Seek to %2.0f%% (%2d:%02d:%02d) of total duration (%2d:%02d:%02d)       \n", frac*100,
                            hh, mm, ss, thh, tmm, tss);
                    ts = frac * cur_stream->ic->duration;
                    if (cur_stream->ic->start_time != AV_NOPTS_VALUE)
                        ts += cur_stream->ic->start_time;
                        
                    stream_seek(cur_stream, ts, 0, 0);
                    if(auxlilary_stream)
                        stream_seek(auxlilary_stream, ts, 0, 0);
                }
            }
            else if(mouse_action == 1) // reset vert split position
            {
                cur_stream->last_vert_split_pos = cur_stream->vert_split_pos;
                cur_stream->vert_split_pos = x / cur_stream->width * cur_stream->scaleto_width;
                video_display(cur_stream, auxlilary_stream);
            }
            break;
        case SDL_VIDEORESIZE:
                screen = SDL_SetVideoMode(FFMIN(16383, event.resize.w), event.resize.h, 0,
                                          SDL_HWSURFACE|(is_full_screen?SDL_FULLSCREEN:SDL_RESIZABLE)|SDL_ASYNCBLIT|SDL_HWACCEL|SDL_DOUBLEBUF);
                if (!screen) {
                    av_log(NULL, AV_LOG_FATAL, "Failed to set video mode\n");
                    do_exit(cur_stream);
                }
                screen_width  = cur_stream->width  = screen->w;
                screen_height = cur_stream->height = screen->h;
                cur_stream->force_refresh = 1;
            break;
        case SDL_QUIT:
        case FF_QUIT_EVENT:
            do_exit(cur_stream);
            break;
        case FF_ALLOC_EVENT:
            alloc_picture(event.user.data1);
            break;
        default:
            break;
        }
    }
}

static int opt_frame_size(void *optctx, const char *opt, const char *arg)
{
    av_log(NULL, AV_LOG_WARNING, "Option -s is deprecated, use -video_size.\n");
    return opt_default(NULL, "video_size", arg);
}

static int opt_width(void *optctx, const char *opt, const char *arg)
{
    screen_width = parse_number_or_die(opt, arg, OPT_INT64, 1, INT_MAX);
    return 0;
}

static int opt_height(void *optctx, const char *opt, const char *arg)
{
    screen_height = parse_number_or_die(opt, arg, OPT_INT64, 1, INT_MAX);
    return 0;
}

static int opt_format(void *optctx, const char *opt, const char *arg)
{
    file_iformat = av_find_input_format(arg);
    if (!file_iformat) {
        av_log(NULL, AV_LOG_FATAL, "Unknown input format: %s\n", arg);
        return AVERROR(EINVAL);
    }
    return 0;
}

static int opt_frame_pix_fmt(void *optctx, const char *opt, const char *arg)
{
    av_log(NULL, AV_LOG_WARNING, "Option -pix_fmt is deprecated, use -pixel_format.\n");
    return opt_default(NULL, "pixel_format", arg);
}

static int opt_sync(void *optctx, const char *opt, const char *arg)
{
    if (!strcmp(arg, "audio"))
        av_sync_type = AV_SYNC_AUDIO_MASTER;
    else if (!strcmp(arg, "video"))
        av_sync_type = AV_SYNC_VIDEO_MASTER;
    else if (!strcmp(arg, "ext"))
        av_sync_type = AV_SYNC_EXTERNAL_CLOCK;
    else {
        av_log(NULL, AV_LOG_ERROR, "Unknown value for %s: %s\n", opt, arg);
        exit(1);
    }
    return 0;
}

static int opt_seek(void *optctx, const char *opt, const char *arg)
{
    start_time = parse_time_or_die(opt, arg, 1);
    return 0;
}

static int opt_duration(void *optctx, const char *opt, const char *arg)
{
    duration = parse_time_or_die(opt, arg, 1);
    return 0;
}

static int opt_show_mode(void *optctx, const char *opt, const char *arg)
{
    show_mode = !strcmp(arg, "video") ? SHOW_MODE_VIDEO :
                !strcmp(arg, "waves") ? SHOW_MODE_WAVES :
                !strcmp(arg, "rdft" ) ? SHOW_MODE_RDFT  :
                parse_number_or_die(opt, arg, OPT_INT, 0, SHOW_MODE_NB-1);
    return 0;
}

static void opt_input_file(void *optctx, const char *filename)
{
    char** i_fname = input_filename[0] == NULL? (char **)input_filename: (char **)input_filename + 1;
    if (*i_fname) {
        av_log(NULL, AV_LOG_FATAL,
               "Argument '%s' provided as input filename, but '%s' was already specified.\n",
                filename, *i_fname);
        exit(1);
    }
    if (!strcmp(filename, "-"))
        filename = "pipe:";
    *i_fname = (char *)filename;
}

static int opt_codec(void *optctx, const char *opt, const char *arg)
{
   const char *spec = strchr(opt, ':');
   if (!spec) {
       av_log(NULL, AV_LOG_ERROR,
              "No media specifier was specified in '%s' in option '%s'\n",
               arg, opt);
       return AVERROR(EINVAL);
   }
   spec++;
   switch (spec[0]) {
   case 'a' :    audio_codec_name = arg; break;
   case 's' : subtitle_codec_name = arg; break;
   case 'v' :    video_codec_name = arg; break;
   default:
       av_log(NULL, AV_LOG_ERROR,
              "Invalid media specifier '%s' in option '%s'\n", spec, opt);
       return AVERROR(EINVAL);
   }
   return 0;
}

static int dummy;
static int is_move;

static const OptionDef options[] = {
#include "cmdutils_common_opts.h"
    { "m", OPT_BOOL, { &is_move}, "move split line automaticlly"},
    { "x", HAS_ARG, { .func_arg = opt_width }, "force displayed width", "width" },
    { "y", HAS_ARG, { .func_arg = opt_height }, "force displayed height", "height" },
    { "s", HAS_ARG | OPT_VIDEO, { .func_arg = opt_frame_size }, "set frame size (WxH or abbreviation)", "size" },
    { "fs", OPT_BOOL, { &is_full_screen }, "force full screen" },
    { "an", OPT_BOOL, { &audio_disable }, "disable audio" },
    { "vn", OPT_BOOL, { &video_disable }, "disable video" },
    { "sn", OPT_BOOL, { &subtitle_disable }, "disable subtitling" },
    { "ast", OPT_STRING | HAS_ARG | OPT_EXPERT, { &wanted_stream_spec[AVMEDIA_TYPE_AUDIO] }, "select desired audio stream", "stream_specifier" },
    { "vst", OPT_STRING | HAS_ARG | OPT_EXPERT, { &wanted_stream_spec[AVMEDIA_TYPE_VIDEO] }, "select desired video stream", "stream_specifier" },
    { "sst", OPT_STRING | HAS_ARG | OPT_EXPERT, { &wanted_stream_spec[AVMEDIA_TYPE_SUBTITLE] }, "select desired subtitle stream", "stream_specifier" },
    { "ss", HAS_ARG, { .func_arg = opt_seek }, "seek to a given position in seconds", "pos" },
    { "t", HAS_ARG, { .func_arg = opt_duration }, "play  \"duration\" seconds of audio/video", "duration" },
    { "bytes", OPT_INT | HAS_ARG, { &seek_by_bytes }, "seek by bytes 0=off 1=on -1=auto", "val" },
    { "nodisp", OPT_BOOL, { &display_disable }, "disable graphical display" },
    { "f", HAS_ARG, { .func_arg = opt_format }, "force format", "fmt" },
    { "pix_fmt", HAS_ARG | OPT_EXPERT | OPT_VIDEO, { .func_arg = opt_frame_pix_fmt }, "set pixel format", "format" },
    { "stats", OPT_BOOL | OPT_EXPERT, { &show_status }, "show status", "" },
    { "fast", OPT_BOOL | OPT_EXPERT, { &fast }, "non spec compliant optimizations", "" },
    { "genpts", OPT_BOOL | OPT_EXPERT, { &genpts }, "generate pts", "" },
    { "drp", OPT_INT | HAS_ARG | OPT_EXPERT, { &decoder_reorder_pts }, "let decoder reorder pts 0=off 1=on -1=auto", ""},
    { "lowres", OPT_INT | HAS_ARG | OPT_EXPERT, { &lowres }, "", "" },
    { "sync", HAS_ARG | OPT_EXPERT, { .func_arg = opt_sync }, "set audio-video sync. type (type=audio/video/ext)", "type" },
    { "autoexit", OPT_BOOL | OPT_EXPERT, { &autoexit }, "exit at the end", "" },
    { "exitonkeydown", OPT_BOOL | OPT_EXPERT, { &exit_on_keydown }, "exit on key down", "" },
    { "exitonmousedown", OPT_BOOL | OPT_EXPERT, { &exit_on_mousedown }, "exit on mouse down", "" },
    { "loop", OPT_INT | HAS_ARG | OPT_EXPERT, { &loop }, "set number of times the playback shall be looped", "loop count" },
    { "framedrop", OPT_BOOL | OPT_EXPERT, { &framedrop }, "drop frames when cpu is too slow", "" },
    { "infbuf", OPT_BOOL | OPT_EXPERT, { &infinite_buffer }, "don't limit the input buffer size (useful with realtime streams)", "" },
    { "window_title", OPT_STRING | HAS_ARG, { &window_title }, "set window title", "window title" },
#if CONFIG_AVFILTER
    { "vf", OPT_EXPERT | HAS_ARG, { .func_arg = opt_add_vfilter }, "set video filters", "filter_graph" },
    { "af", OPT_STRING | HAS_ARG, { &afilters }, "set audio filters", "filter_graph" },
#endif
    { "rdftspeed", OPT_INT | HAS_ARG| OPT_AUDIO | OPT_EXPERT, { &rdftspeed }, "rdft speed", "msecs" },
    { "showmode", HAS_ARG, { .func_arg = opt_show_mode}, "select show mode (0 = video, 1 = waves, 2 = RDFT)", "mode" },
    { "default", HAS_ARG | OPT_AUDIO | OPT_VIDEO | OPT_EXPERT, { .func_arg = opt_default }, "generic catch all option", "" },
    { "i", OPT_BOOL, { &dummy}, "read specified file", "input_file"},
    { "codec", HAS_ARG, { .func_arg = opt_codec}, "force decoder", "decoder_name" },
    { "acodec", HAS_ARG | OPT_STRING | OPT_EXPERT, {    &audio_codec_name }, "force audio decoder",    "decoder_name" },
    { "scodec", HAS_ARG | OPT_STRING | OPT_EXPERT, { &subtitle_codec_name }, "force subtitle decoder", "decoder_name" },
    { "vcodec", HAS_ARG | OPT_STRING | OPT_EXPERT, {    &video_codec_name }, "force video decoder",    "decoder_name" },
    { "autorotate", OPT_BOOL, { &autorotate }, "automatically rotate video", "" },
    { NULL, },
};

static void show_usage(void)
{
    av_log(NULL, AV_LOG_FATAL, "Visual Comparision Tool Based on ffplay, version 1.0.%d.%d\n", ver_major, ver_minor);
    av_log(NULL, AV_LOG_FATAL, "Usage: %s  input_file1, input_file2 [-loop 3] [-m]\n", program_name);
    av_log(NULL, AV_LOG_FATAL, "Options:\n");
    av_log(NULL, AV_LOG_FATAL, "       -loop N[integer]   loop play N times\n");
    av_log(NULL, AV_LOG_FATAL, "       -m                 auto move split line\n");
    av_log(NULL, AV_LOG_FATAL, "Note :\n");
    av_log(NULL, AV_LOG_INFO,  "       input_file1 display at left side of the vertical split line, input_file2 display at right side\n");
    av_log(NULL, AV_LOG_INFO,  "       Click left mouse to move the split line; Or keep left mouse down, then vertical split line moves following mouse movement\n");
    av_log(NULL, AV_LOG_INFO,  "       To support seek, file format should be the same between the two input files\n\n");
    av_log(NULL, AV_LOG_FATAL, "While playing:\n");
    av_log(NULL, AV_LOG_INFO,  "             q, ESC                quit\n");
    av_log(NULL, AV_LOG_INFO,  "             f                     toggle full screen\n");
    av_log(NULL, AV_LOG_INFO,  "             p, SPC                pause\n");
    av_log(NULL, AV_LOG_FATAL, "             s                     activate frame-step mode, step forward one frame for two input files\n");
    av_log(NULL, AV_LOG_FATAL, "             F1                    step forward one frame for the first  input file while paused, to synchronize two files\n");
    av_log(NULL, AV_LOG_FATAL, "             F2                    step forward one frame for the second input file while paused, to synchronize two files\n");
    av_log(NULL, AV_LOG_INFO,  "             right mouse click     seek to percentage in file corresponding to fraction of width\n");
    av_log(NULL, AV_LOG_INFO,  "             left/right            seek backward/forward 10 seconds\n");
    av_log(NULL, AV_LOG_INFO,  "             down/up               seek backward/forward 1 minute\n");
    av_log(NULL, AV_LOG_INFO,  "             left  mouse click     move the vertical split line to mouse position\n");
    av_log(NULL, AV_LOG_FATAL, "             left  mouse down      The vertical split line will move following mouse position\n");
    av_log(NULL, AV_LOG_INFO, "\n");
}

void show_help_default(const char *opt, const char *arg)
{
    av_log_set_callback(log_callback_help);
    show_usage();
    return;
    show_help_options(options, "Main options:", 0, OPT_EXPERT, 0);
    show_help_options(options, "Advanced options:", OPT_EXPERT, 0, 0);
    printf("\n");
    show_help_children(avcodec_get_class(), AV_OPT_FLAG_DECODING_PARAM);
    show_help_children(avformat_get_class(), AV_OPT_FLAG_DECODING_PARAM);
#if !CONFIG_AVFILTER
    show_help_children(sws_get_class(), AV_OPT_FLAG_ENCODING_PARAM);
#else
    show_help_children(avfilter_get_class(), AV_OPT_FLAG_FILTERING_PARAM);
#endif
    printf("\nWhile playing:\n"
           "q, ESC              quit\n"
           "f                   toggle full screen\n"
           "p, SPC              pause\n"
           "m                   toggle mute\n"
           "9, 0                decrease and increase volume respectively\n"
           "/, *                decrease and increase volume respectively\n"
           "a                   cycle audio channel in the current program\n"
           "v                   cycle video channel\n"
           "t                   cycle subtitle channel in the current program\n"
           "c                   cycle program\n"
           "w                   cycle video filters or show modes\n"
           "s                   activate frame-step mode\n"
           "left/right          seek backward/forward 10 seconds\n"
           "down/up             seek backward/forward 1 minute\n"
           "page down/page up   seek backward/forward 10 minutes\n"
           "right mouse click   seek to percentage in file corresponding to fraction of width\n"
           "left double-click   toggle full screen\n"
           );
}

static int lockmgr(void **mtx, enum AVLockOp op)
{
   switch(op) {
      case AV_LOCK_CREATE:
          *mtx = SDL_CreateMutex();
          if(!*mtx) {
              av_log(NULL, AV_LOG_FATAL, "SDL_CreateMutex(): %s\n", SDL_GetError());
              return 1;
          }
          return 0;
      case AV_LOCK_OBTAIN:
          return !!SDL_LockMutex(*mtx);
      case AV_LOCK_RELEASE:
          return !!SDL_UnlockMutex(*mtx);
      case AV_LOCK_DESTROY:
          SDL_DestroyMutex(*mtx);
          return 0;
   }
   return 1;
}

/* Called from the main */
int main(int argc, char **argv)
{
    int flags;
    VideoState *is, *is2 = NULL;
    char dummy_videodriver[] = "SDL_VIDEODRIVER=dummy";
    char alsa_bufsize[] = "SDL_AUDIO_ALSA_SET_BUFFER_SIZE=1";

    av_log_set_flags(AV_LOG_SKIP_REPEATED);
    parse_loglevel(argc, argv, options);

    /* register all codecs, demux and protocols */
#if CONFIG_AVDEVICE
    avdevice_register_all();
#endif
#if CONFIG_AVFILTER
    avfilter_register_all();
#endif
    av_register_all();
    avformat_network_init();

    init_opts();

    signal(SIGINT , sigterm_handler); /* Interrupt (ANSI).    */
    signal(SIGTERM, sigterm_handler); /* Termination (ANSI).  */

    //show_banner(argc, argv, options);

    parse_options(NULL, argc, argv, options, opt_input_file);

    if (!input_filename[0]) {
        show_usage();
        av_log(NULL, AV_LOG_INFO, "At least one input file must be specified\n");
        av_log(NULL, AV_LOG_INFO,
               "Use -h to get full help or, even better, run 'man %s'\n", program_name);
        exit(1);
    }

    if (display_disable) {
        video_disable = 1;
    }
    flags = SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER;
    if (audio_disable)
        flags &= ~SDL_INIT_AUDIO;
    else {
        /* Try to work around an occasional ALSA buffer underflow issue when the
         * period size is NPOT due to ALSA resampling by forcing the buffer size. */
        if (!SDL_getenv("SDL_AUDIO_ALSA_SET_BUFFER_SIZE"))
            SDL_putenv(alsa_bufsize);
    }
    if (display_disable)
        SDL_putenv(dummy_videodriver); /* For the event queue, we always need a video driver. */
#if !defined(_WIN32) && !defined(__APPLE__)
    flags |= SDL_INIT_EVENTTHREAD; /* Not supported on Windows or Mac OS X */
#endif
    if (SDL_Init (flags)) {
        av_log(NULL, AV_LOG_FATAL, "Could not initialize SDL - %s\n", SDL_GetError());
        av_log(NULL, AV_LOG_FATAL, "(Did you set the DISPLAY variable?)\n");
        exit(1);
    }

    if (!display_disable) {
        const SDL_VideoInfo *vi = SDL_GetVideoInfo();
        fs_screen_width = vi->current_w;
        fs_screen_height = vi->current_h;
    }

    SDL_EventState(SDL_ACTIVEEVENT, SDL_IGNORE);
    SDL_EventState(SDL_SYSWMEVENT, SDL_IGNORE);
    SDL_EventState(SDL_USEREVENT, SDL_IGNORE);

    SDL_EnableKeyRepeat(SDL_DEFAULT_REPEAT_DELAY, SDL_DEFAULT_REPEAT_INTERVAL);

    if (av_lockmgr_register(lockmgr)) {
        av_log(NULL, AV_LOG_FATAL, "Could not initialize lock manager!\n");
        do_exit(NULL);
    }

    av_init_packet(&flush_pkt);
    flush_pkt.data = (uint8_t *)&flush_pkt;

    is = stream_open(input_filename[0], file_iformat);
    if(input_filename[1])
    {
        av_usleep((int64_t)(0.100 * 1000000.0)); // sleep 100ms wait first stream finish init
        audio_disable = 1; // two input files means comparision mode, so disable audio of second stream
        is2 = stream_open(input_filename[1], file_iformat);
        if(!is2)
        {
            av_log(NULL, AV_LOG_FATAL, "Failed to initialize VideoState2 for file %s!\n", input_filename[1]);
            do_exit(NULL);
        }
        
        while(is->viddec_width == 0 || is2->viddec_width == 0) // wait until read_thread has got the resolution information
            av_usleep((int64_t)(0.001 * 1000000.0)); // sleep 1ms
        
        int  max_width = FFMAX(is->viddec_width,  is2->viddec_width);
        int max_height = FFMAX(is->viddec_height, is2->viddec_height);
        is->scaleto_width  = is2->scaleto_width  = max_width;
        is->scaleto_height = is2->scaleto_height = max_height;
                
        for(int i = 0; i < argc; i++)
            if(strcmp(argv[i], "-m") == 0)
                is->mov_speed = is->scaleto_width / 400;
        
        is->bk_data[0]  = av_malloc(is->scaleto_width * is->scaleto_height);
        is->bk_data[1]  = av_malloc(is->scaleto_width * is->scaleto_height / 2);
        is->bk_data[2]  = av_malloc(is->scaleto_width * is->scaleto_height / 2);
        is2->bk_data[0] = av_malloc(is2->scaleto_width * is2->scaleto_height);
        is2->bk_data[1] = av_malloc(is2->scaleto_width * is2->scaleto_height / 2);
        is2->bk_data[2] = av_malloc(is2->scaleto_width * is2->scaleto_height / 2);
        
        if(is->viddec_width != is2->viddec_width || is->viddec_height != is2->viddec_height)
            av_log(NULL, AV_LOG_WARNING, "Resolution doesn't match between two input files, Scale to %d x %d\n", is->scaleto_width, is->scaleto_height);
    }

    
    if (!is) {
        av_log(NULL, AV_LOG_FATAL, "Failed to initialize VideoState!\n");
        do_exit(NULL);
    }
    
    event_loop(is, is2);

    /* never returns */
    return 0;
}