Scaling tx video

.gitignore

@@ -0,0 +1 @@
+*.log

README.md

@@ -129,13 +129,15 @@ dvledtx uses a JSON config file with three sections:
 | **interfaces** | `name` | PCI BDF address of the NIC (e.g. `0000:06:00.0`) |
 | | `sip` | Source IP address |
 | | `dip` | Destination multicast IP address |
-| **video** | `width` | Frame width in pixels |
-| | `height` | Frame height in pixels |
+| **video** | `width` | Source frame width in pixels |
+| | `height` | Source frame height in pixels |
+| | `tx_url` | Path to the source video file |
+| **tx_video** | `scale_width` | (Optional) Output width after scaling |
+| | `scale_height` | (Optional) Output height after scaling |
 | | `fps` | Frames per second (25, 30, 50, 60) |
 | | `fmt` | Pixel format (see [Supported Formats](#supported-formats)) |
-| | `tx_url` | Path to the source video file |
 | **tx_sessions[]** | `udp_port` | UDP port for the session |
-| | `payload_type` | RTP payload type (typically 96) |
+| | `payload_type` | (Optional) RTP payload type — defaults to `96` if not present |
 | | `crop` | Region to transmit: `x`, `y`, `w`, `h` in pixels |
 
 Example (`config/tx_fullhd_single_session.json`):
@@ -146,12 +148,14 @@ Example (`config/tx_fullhd_single_session.json`):
     { "name": "0000:06:00.0", "sip": "192.168.50.29", "dip": "239.168.85.20" }
   ],
   "video": {
-    "width": 1920, "height": 1080, "fps": 30,
-    "fmt": "yuv422p10le",
+    "width": 1920, "height": 1080,
     "tx_url": "bbb_sunflower_1080p_30fps_normal.mp4"
   },
+  "tx_video": {
+    "fps": 30, "fmt": "yuv422p10le"
+  },
   "tx_sessions": [
-    { "udp_port": 20000, "payload_type": 96, "crop": { "x": 0, "y": 0, "w": 1920, "h": 1080 } }
+    { "udp_port": 20000, "crop": { "x": 0, "y": 0, "w": 1920, "h": 1080 } }
   ]
 }
 ```
@@ -236,6 +240,43 @@ When `log_file` is set, log output is written to that file in addition to the co
 
 > **Note:** Maximum supported resolution is 3840x2160. Width must be even for YUV format alignment.
 
+### Video Scaling
+
+dvledtx supports upscaling and downscaling via optional `scale_width` and `scale_height` fields in the video configuration block. When set, the decoded source video is scaled to the specified dimensions before crop regions are applied.
+
+| Feature | Description |
+|---------|-------------|
+| **Upscale** | Scale smaller source (e.g. 1080p) to larger output (e.g. 4K) |
+| **Downscale** | Scale larger source (e.g. 4K) to smaller output (e.g. 1080p) |
+| **Single session** | Full scaled frame transmitted as one stream |
+| **Multi-session** | Crop regions applied to scaled frame for tiled LED walls |
+| **Max output** | 3840x2160 (4K UHD) |
+
+Example — upscale 1080p source to 4K output:
+```json
+{
+  "video": {
+    "width": 1920, "height": 1080,
+    "tx_url": "source_1080p.mp4"
+  },
+  "tx_video": {
+    "scale_width": 3840, "scale_height": 2160,
+    "fps": 30, "fmt": "yuv422p10le"
+  },
+  "tx_sessions": [
+    { "udp_port": 20000, "crop": { "x": 0, "y": 0, "w": 3840, "h": 2160 } }
+  ]
+}
+```
+
+Log output when scaling is active:
+```
+[INFO ] Video: 1920x1080 -> scale 3840x2160 30fps yuv422p10le  tx_url=source_1080p.mp4
+[INFO ]   Session 0: udp_port=20000 pt=96 crop=[0,0 3840x2160]
+```
+
+> **Note:** When `scale_width`/`scale_height` are set, crop bounds are validated against the scaled dimensions, not the source dimensions. Both fields must be specified together, and the scaled dimensions must satisfy the pixel format's chroma-alignment constraints (e.g. `yuv420` requires even width and height; `yuv422*` requires even width).
+
 ## Performance Considerations
 
 ### Optimization Features

config/tx_2k_multi_session.json

@@ -2,32 +2,33 @@
   "log_file": "dvledtx.log",
   "interfaces": [
     {
-      "name": "0000:03:00.1",
+      "name": "0000:06:00.0",
       "sip":  "192.168.50.29",
       "dip":  "239.168.85.20"
     }
   ],
   "video": {
     "width":  2560,
     "height": 1440,
+    "tx_url": "bbb_sunflower_1080p_30fps_normal.mp4"
+  },
+  "tx_video": {
+    "scale_width":  2560,
+    "scale_height": 1440,
     "fps":    30,
-    "fmt":    "yuv422p10le",
-    "tx_url": "ball_2k_yuv420p_30fps_5min.mp4"
+    "fmt":    "yuv422p10le"
   },
   "tx_sessions": [
     {
       "udp_port":     20000,
-      "payload_type": 96,
       "crop": { "x": 0,    "y": 0, "w": 854, "h": 1440 }
     },
     {
       "udp_port":     20002,
-      "payload_type": 96,
       "crop": { "x": 854,  "y": 0, "w": 854, "h": 1440 }
     },
     {
       "udp_port":     20004,
-      "payload_type": 96,
       "crop": { "x": 1708, "y": 0, "w": 852, "h": 1440 }
     }
   ]

config/tx_2k_single_session.json

@@ -10,14 +10,17 @@
   "video": {
     "width":  2560,
     "height": 1440,
-    "fps":    30,
-    "fmt":    "yuv422p10le",
     "tx_url": "ball_2k_yuv420p_30fps_5min.mp4"
   },
+  "tx_video": {
+    "scale_width":  2560,
+    "scale_height": 1440,
+    "fps":    30,
+    "fmt":    "yuv422p10le"
+  },
   "tx_sessions": [
     {
       "udp_port":     20000,
-      "payload_type": 96,
       "crop": { "x": 0, "y": 0, "w": 2560, "h": 1440 }
     }
   ]

config/tx_4k_multi_session.json

@@ -10,25 +10,26 @@
   "video": {
     "width":  3840,
     "height": 2160,
+    "tx_url": "ball_4k_gbrp10le_60fps_5min.mp4"
+  },
+  "tx_video": {
+    "scale_width":  1920,
+    "scale_height": 1080,
     "fps":    30,
-    "fmt":    "yuv422p10le",
-    "tx_url": "ball_4k_yuv420p_30fps_5min.mp4"
+    "fmt":    "yuv422p10le"
   },
   "tx_sessions": [
     {
       "udp_port":     20000,
-      "payload_type": 96,
-      "crop": { "x": 0,    "y": 0, "w": 1280, "h": 2160 }
+      "crop": { "x": 0,    "y": 0, "w": 640, "h": 1080 }
     },
     {
       "udp_port":     20002,
-      "payload_type": 96,
-      "crop": { "x": 1280, "y": 0, "w": 1280, "h": 2160 }
+      "crop": { "x": 640, "y": 0, "w": 640, "h": 1080 }
     },
     {
       "udp_port":     20004,
-      "payload_type": 96,
-      "crop": { "x": 2560, "y": 0, "w": 1280, "h": 2160 }
+      "crop": { "x": 1280, "y": 0, "w": 640, "h": 1080 }
     }
   ]
 }

config/tx_4k_single_session.json

@@ -10,15 +10,18 @@
   "video": {
     "width":  3840,
     "height": 2160,
+    "tx_url": "ball_4k_gbrp10le_60fps_5min.mp4"
+  },
+  "tx_video": {
+    "scale_width":  900,
+    "scale_height": 600,
     "fps":    30,
-    "fmt":    "yuv422p10le",
-    "tx_url": "ball_4k_yuv420p_30fps_5min.mp4"
+    "fmt":    "yuv422p10le"
   },
   "tx_sessions": [
     {
       "udp_port":     20000,
-      "payload_type": 96,
-      "crop": { "x": 0, "y": 0, "w": 3840, "h": 2160 }
+      "crop": { "x": 0, "y": 0, "w": 900, "h": 600 }
     }
   ]
 }

config/tx_fullhd_multi_session.json

@@ -10,24 +10,25 @@
   "video": {
     "width":  1920,
     "height": 1080,
-    "fps":    30,
-    "fmt":    "yuv422p10le",
     "tx_url": "bbb_sunflower_1080p_30fps_normal.mp4"
   },
+  "tx_video": {
+    "scale_width":  1920,
+    "scale_height": 1080,
+    "fps":    30,
+    "fmt":    "yuv422p10le"
+  },
   "tx_sessions": [
     {
       "udp_port":     20000,
-      "payload_type": 96,
       "crop": { "x": 0,    "y": 0, "w": 640, "h": 1080 }
     },
     {
       "udp_port":     20002,
-      "payload_type": 96,
       "crop": { "x": 640,  "y": 0, "w": 640, "h": 1080 }
     },
     {
       "udp_port":     20004,
-      "payload_type": 96,
       "crop": { "x": 1280, "y": 0, "w": 640, "h": 1080 }
     }
   ]

config/tx_fullhd_single_session.json

@@ -2,23 +2,26 @@
   "log_file": "dvledtx.log",
   "interfaces": [
     {
-      "name": "0000:03:00.1",
+      "name": "0000:06:00.0",
       "sip":  "192.168.50.29",
       "dip":  "239.168.85.20"
     }
   ],
   "video": {
     "width":  3840,
     "height": 2160,
-    "fps":    60,
-    "fmt":    "gbrp10le",
-    "tx_url": "ball_4k_gbrp10le_30fps_5min.mp4"
+    "tx_url": "bbb_sunflower_1080p_30fps_normal.mp4"
+  },
+  "tx_video": {
+    "scale_width":  3840,
+    "scale_height": 2160,
+    "fps":    30,
+    "fmt":    "yuv422p10le"
   },
   "tx_sessions": [
     {
       "udp_port":     20000,
-      "payload_type": 96,
-      "crop": { "x": 0, "y": 0, "w": 3840, "h": 2160 }
+      "crop": { "x": 0, "y": 0, "w": 1920, "h": 1080 }
     }
   ]
 }

include/app_context.h

@@ -37,6 +37,8 @@ struct dvledtx_context {
   /* Video parameters */
   uint32_t width;
   uint32_t height;
+  uint32_t scale_width;       /* output width after scaling (0 = no scaling) */
+  uint32_t scale_height;      /* output height after scaling (0 = no scaling) */
   int fps;                    /* frames per second: 25, 30, 50, 60 */
   enum AVPixelFormat fmt;     /* e.g. AV_PIX_FMT_YUV422P10LE */
 

include/util/config_reader.h

@@ -30,6 +30,8 @@ struct dvledtx_config {
   /* video block */
   uint32_t width;
   uint32_t height;
+  uint32_t scale_width;   /* 0 = no scaling (use source width) */
+  uint32_t scale_height;  /* 0 = no scaling (use source height) */
   int      fps;
   char     fmt[32];         /* e.g. "yuv422p10le" */
   char     tx_url[256];

src/core/session_manager.c

@@ -51,8 +51,10 @@ static void* st20p_tx_thread_shared(void* arg) {
   struct shared_decode_ctx* dec = ctx->shared_dec;
   int crop_x = ctx->crop_x_offset;
   int crop_y = ctx->crop_y_offset;
-  int crop_w = ctx->crop_width  > 0 ? ctx->crop_width  : (int)ctx->app->width;
-  int crop_h = ctx->crop_height > 0 ? ctx->crop_height : (int)ctx->app->height;
+  int eff_w  = (int)(ctx->app->scale_width  > 0 ? ctx->app->scale_width  : ctx->app->width);
+  int eff_h  = (int)(ctx->app->scale_height > 0 ? ctx->app->scale_height : ctx->app->height);
+  int crop_w = ctx->crop_width  > 0 ? ctx->crop_width  : eff_w;
+  int crop_h = ctx->crop_height > 0 ? ctx->crop_height : eff_h;
 
   LOG_INFO("ST20P TX(%d): shared thread started (crop x=%d y=%d w=%d h=%d)",
            ctx->idx, crop_x, crop_y, crop_w, crop_h);
@@ -169,8 +171,10 @@ static void* st20p_tx_thread(void* arg) {
    * Path B yuv_frame is already crop-sized (strip) → no offset needed. */
   int crop_x = (ctx->use_ffmpeg == true) ? ctx->crop_x_offset : 0;
   int crop_y = (ctx->use_ffmpeg == true) ? ctx->crop_y_offset : 0;
-  int crop_w = ctx->crop_width  > 0 ? ctx->crop_width  : (int)ctx->app->width;
-  int crop_h = ctx->crop_height > 0 ? ctx->crop_height : (int)ctx->app->height;
+  int eff_w  = (int)(ctx->app->scale_width  > 0 ? ctx->app->scale_width  : ctx->app->width);
+  int eff_h  = (int)(ctx->app->scale_height > 0 ? ctx->app->scale_height : ctx->app->height);
+  int crop_w = ctx->crop_width  > 0 ? ctx->crop_width  : eff_w;
+  int crop_h = ctx->crop_height > 0 ? ctx->crop_height : eff_h;
 
   while (ctx->app->exit == false && session_manager_should_exit() == false) {
     const AVFrame* frame = tx_fetch_next_frame(ctx);
@@ -217,13 +221,15 @@ int create_st20p_tx_session(session_manager_t* manager, struct dvledtx_context*
   /* Fallback: divide the frame width evenly across all sessions */
   if (ctx->crop_width == 0 || ctx->crop_height == 0) {
     int total   = app->st20p_sessions > 0 ? app->st20p_sessions : 1;
-    int strip_w = (int)app->width / total;
+    int eff_w   = (int)(app->scale_width  > 0 ? app->scale_width  : app->width);
+    int eff_h   = (int)(app->scale_height > 0 ? app->scale_height : app->height);
+    int strip_w = eff_w / total;
     ctx->crop_x_offset = session_idx * strip_w;
     ctx->crop_y_offset = 0;
     ctx->crop_width  = (session_idx == total - 1)
-                       ? ((int)app->width - ctx->crop_x_offset)
+                       ? (eff_w - ctx->crop_x_offset)
                        : strip_w;
-    ctx->crop_height = (int)app->height;
+    ctx->crop_height = eff_h;
   }
   LOG_INFO("ST20P TX session %d: crop rect x=%d y=%d w=%d h=%d",
            session_idx, ctx->crop_x_offset, ctx->crop_y_offset,

src/ffmpeg/ffmpeg_decoder.c

@@ -321,9 +321,11 @@ static void close_ffmpeg_decoder(
  * ========================================================================= */
 int open_shared_ffmpeg(struct shared_decode_ctx* dec, const char* filename) {
   const struct dvledtx_context* app = dec->app;
+  int target_w = (int)(app->scale_width  > 0 ? app->scale_width  : app->width);
+  int target_h = (int)(app->scale_height > 0 ? app->scale_height : app->height);
   return open_ffmpeg_decoder(
     filename, "Shared decode",
-    app->fmt, (int)app->width, (int)app->height,
+    app->fmt, target_w, target_h,
     &dec->fmt_ctx, &dec->codec_ctx, &dec->sws_ctx,
     &dec->av_frame, &dec->yuv_frame, &dec->av_packet,
     &dec->video_stream_idx);
@@ -341,9 +343,11 @@ void close_shared_ffmpeg(struct shared_decode_ctx* dec) {
 static int open_ffmpeg_source(struct st20p_tx_ctx* ctx, const char* filename) {
   char log_prefix[64];
   snprintf(log_prefix, sizeof(log_prefix), "ST20P TX(%d)", ctx->idx);
+  int target_w = (int)(ctx->app->scale_width  > 0 ? ctx->app->scale_width  : ctx->app->width);
+  int target_h = (int)(ctx->app->scale_height > 0 ? ctx->app->scale_height : ctx->app->height);
   int ret = open_ffmpeg_decoder(
     filename, log_prefix,
-    ctx->app->fmt, (int)ctx->app->width, (int)ctx->app->height,
+    ctx->app->fmt, target_w, target_h,
     &ctx->fmt_ctx, &ctx->codec_ctx, &ctx->sws_ctx,
     &ctx->av_frame, &ctx->yuv_frame, &ctx->av_packet,
     &ctx->video_stream_idx);