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Add Linux ALSA MIDI support and amy-synth target #563

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8 changes: 7 additions & 1 deletion Makefile
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
# Makefile for AMY , including an example

TARGET = amy-example amy-message amy-piano
TARGET = amy-example amy-message amy-piano amy-synth
LIBS = -lm -pthread

UNAME_S := $(shell uname -s)
Expand All @@ -13,6 +13,10 @@ ifeq ($(UNAME_S),Darwin)
CC = clang
else
CC = gcc
ifeq ($(UNAME_S),Linux)
SOURCES += src/linux_midi.c
LIBS += -lasound
endif
endif


Expand Down Expand Up @@ -76,6 +80,8 @@ src/patches.h: $(PYTHONS) $(HEADERS_BUILD)
amy-example: $(OBJECTS) src/amy-example.o
$(CC) $(CFLAGS) $(OBJECTS) src/amy-example.o -Wall $(LIBS) -o $@

amy-synth: $(OBJECTS) src/amy-synth.o
$(CC) $(CFLAGS) $(OBJECTS) src/amy-synth.o -Wall $(LIBS) -o $@

amy-piano: $(OBJECTS) src/amy-piano.o
$(CC) $(CFLAGS) $(OBJECTS) src/amy-piano.o -Wall $(LIBS) -o $@
Expand Down
307 changes: 307 additions & 0 deletions src/alsa_raw_test.c
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Original file line number Diff line number Diff line change
@@ -0,0 +1,307 @@
#include <stdio.h>
#include <pthread.h>
#include <alsa/asoundlib.h>

/*
gcc -c alsa_raw_test.c
gcc -o alsa_raw_test alsa_raw_test.o -lasound
*/

#define MF_FIX_NOTEOFF 0x01 // always translate [9n,kk,00] to [8n,kk,64]
#define MF_EMU_REL_VEL 0x02 // synthesize rel velocity (so [9n,kk,00]->[8n,kk,vv], real [8n,kk,vv] is unaffected)
#define MF_FWD_ACTSENS 0x04 // forward 0xFE active sensing RT messages (blocked by default)
#define MF_TX_MODIFIED 0x08 // send modified data to MIDI output port

#define MF_FLAG_MASK 0x0F

snd_rawmidi_t *midi_in = NULL;
snd_rawmidi_t *midi_out = NULL;

pthread_t midi_thread;

#define BUFFER_SIZE 256
#define SYSEX_MAX_CPL 16
#define EMU_RVEL_DAMP 3

int mf_flags = MF_FIX_NOTEOFF;
int thread_should_quit = 0;

uint8_t buffer[BUFFER_SIZE];
uint8_t rsts = 0x80;

int rstat_flag = 0;
int sysex_flag = 0;
int rxbyte_cnt = 0;
int sigma_rvel = 0;

int running = 0;

int fix_noteoff, emu_rel_vel, fwd_actsens, tx_modified;

int midi_write(uint8_t *, int);

int midi_open(void)
{
// "virtual" device string creates the bidirectional sequencer bridge
int err = snd_rawmidi_open(&midi_in, &midi_out, "virtual", 0);
if (err < 0) {
fprintf(stderr, "Could not create virtual raw port: %s\n", snd_strerror(err));
return -1;
} else {
fix_noteoff = mf_flags & MF_FIX_NOTEOFF;
emu_rel_vel = mf_flags & MF_EMU_REL_VEL;
fwd_actsens = mf_flags & MF_FWD_ACTSENS;
tx_modified = mf_flags & MF_TX_MODIFIED;
}
return err;
}

void midi_close(void)
{
if (midi_in ) { snd_rawmidi_close(midi_in ); midi_in = NULL; }
if (midi_out) { snd_rawmidi_close(midi_out); midi_out = NULL; }
}

int midi_setflags(int newflg)
{
int oldflg = mf_flags;
mf_flags = newflg & MF_FLAG_MASK;
fix_noteoff = mf_flags & MF_FIX_NOTEOFF;
emu_rel_vel = mf_flags & MF_EMU_REL_VEL;
fwd_actsens = mf_flags & MF_FWD_ACTSENS;
tx_modified = mf_flags & MF_TX_MODIFIED;
return oldflg;
}

#define EMU_RVEL_ROUND (1 << (EMU_RVEL_DAMP - 1))

#define midi_get(x) { x = *buf++; rem--; }

int _upd_sigma(int vel)
{
// emulate release velocity for decoded [9n,kk,vv]->[8n,kk,vv] events
// (which are usually fixed at 64) by applying an exponential moving
// average and rounding to the most recently received velocity values
int scl = (sigma_rvel + EMU_RVEL_ROUND) >> EMU_RVEL_DAMP;
sigma_rvel = sigma_rvel + vel - scl;
scl = (sigma_rvel + EMU_RVEL_ROUND) >> EMU_RVEL_DAMP;
return scl;
}

int _midi_echo(uint8_t d0, uint8_t d1, uint8_t d2, int len)
{
uint8_t tbuf[4];
if ((len < 0) || (len > 3)) return 0;
tbuf[1] = tbuf[2] = tbuf[3] = 0;
if (len > 2) tbuf[2] = d2;
if (len > 1) tbuf[1] = d1;
if (len > 0) tbuf[0] = d0;
if (tx_modified)
return midi_write(&tbuf[0], len);
else return len;
}

#define midi_echo0 _midi_echo(0xFE,0,0,1)
#define midi_echo1(a) _midi_echo(a,0,0,1)
#define midi_echo2(a,b) _midi_echo(a,b,0,2)
#define midi_echo3(a,b,c) _midi_echo(a,b,c,3)

int midi_parse(uint8_t *buf, int len)
{
uint8_t dat0, dat1, dat2;
int cmd, chn, rem, erv;
rem = len;
while (rem > 0) {
midi_get(dat0);
if (sysex_flag) {
if ((dat0 & 0x80) && (dat0 < 0xF7)) {
fprintf(stderr, "\nWARNING : value=%02X - channel of system common data inside SysEx block!\n", dat0);
continue;
} else {
if (dat0 < 0x80) {
fprintf(stdout, " %02Xh", dat0); fflush(stdout);
if (++rxbyte_cnt == SYSEX_MAX_CPL) { fprintf(stdout, "\n"); rxbyte_cnt=0; }
midi_echo1(dat0); continue;
} else {
if ((dat0 == 0xF7) && (rxbyte_cnt > 0)) fprintf(stdout, "\n");
}
}
} else {
if (dat0 < 0x80) { dat1 = dat0; dat0 = rsts; rstat_flag=1; }
else if (dat0 < 0xF0) { midi_get(dat1); rsts = dat0; rstat_flag=0; }
}
cmd = dat0 & 0xF0; chn = dat0 & 0x0F;
if (rstat_flag) fprintf(stdout, " $ ");
else fprintf(stdout, " : ");
switch (cmd) {
case 0x80:
midi_get(dat2); erv=_upd_sigma(dat2);
fprintf(stdout, "\tNoteOff : chn=%02d key=%03d vel=%03d\t(%03d)\n", chn, dat1, dat2, erv);
midi_echo3(dat0,dat1,dat2); break;
case 0x90:
midi_get(dat2);
if (dat2) {
erv=_upd_sigma(dat2);
fprintf(stdout, "\tNoteOn : chn=%02d key=%03d vel=%03d\t(%03d)\n", chn, dat1, dat2, erv);
midi_echo3(dat0,dat1,dat2);
} else {
if (fix_noteoff) { dat0 &= 0xEF; dat2 = 64; fprintf(stdout, "! ", dat0); }
erv=_upd_sigma(dat2); if (emu_rel_vel) dat2 = erv;
fprintf(stdout, "\tNote0ff : chn=%02d key=%03d vel=%03d\t(%03d)\n", chn, dat1, dat2, erv);
midi_echo3(dat0,dat1,dat2);
}
break;
case 0xA0:
midi_get(dat2); fprintf(stdout, "\tKeyPres : chn=%02d key=%03d val=%03d\n", chn, dat1, dat2);
midi_echo3(dat0,dat1,dat2); break;
case 0xB0:
midi_get(dat2); fprintf(stdout, "\tControl : chn=%02d ctl=%03d val=%03d\n", chn, dat1, dat2);
if ((dat1 == 0) && (dat2 == 127)) running = 0; // <- quit request
midi_echo3(dat0,dat1,dat2); break;
case 0xC0:
fprintf(stdout, "\tProgram : chn=%02d prg=%03d\n", chn, dat1);
midi_echo2(dat0,dat1); break;
case 0xD0:
fprintf(stdout, "\tChnPres : chn=%02d val=%03d\n", chn, dat1);
midi_echo2(dat0,dat1); break;
case 0xE0:
midi_get(dat2); fprintf(stdout, "\tPBender : chn=%02d val=+%04d\n", chn, ((dat2 << 7) | dat1) - 8192);
midi_echo3(dat0,dat1,dat2); break;
case 0xF0:
if (dat0 == 0xF2) midi_get(dat1);
switch(dat0) {
case 0xF0:
fprintf(stdout, " Sys Ex : --- System Exclusive block BEGIN ---\n"); sysex_flag=1; rxbyte_cnt=0;
midi_echo1(dat0); break;
case 0xF1:
midi_get(dat1); fprintf(stdout, "\tSys Com : MTC Quarter Frame - T=%d V=%02d\n", dat1 >> 4, dat1 & 15);
midi_echo2(dat0,dat1); break;
case 0xF2:
midi_get(dat2); fprintf(stdout, "\tSys Com : Song Position Pointer - pos=%05d\n", (dat2 << 7) | dat1);
midi_echo3(dat0,dat1,dat2); break;
case 0xF3:
midi_get(dat1); fprintf(stdout, "\tSys Com : Song Select - song #%03d\n", dat1);
midi_echo2(dat0,dat1); break;
case 0xF4: fprintf(stdout, "\tSys Com : reserved 0xF4\n"); break;
case 0xF5: fprintf(stdout, "\tSys Com : reserved 0xF5\n"); break;
case 0xF6:
fprintf(stdout, "\tSys Com : Tune Request\n");
midi_echo1(dat0); break;
case 0xF7:
fprintf(stdout, " Sys Ex : ---- System Exclusive block END ----\n"); sysex_flag=0;
midi_echo1(dat0); break;
case 0xF8:
fprintf(stdout, "\tSys RT : MIDI clock\n");
midi_echo1(dat0); break;
case 0xF9: fprintf(stdout, "\tSys RT : reserved 0xF9\n"); break;
case 0xFA:
fprintf(stdout, "\tSys RT : MIDI start\n");
midi_echo1(dat0); break;
case 0xFB:
fprintf(stdout, "\tSys RT : MIDI continue\n");
midi_echo1(dat0); break;
case 0xFC:
fprintf(stdout, "\tSys RT : MIDI stop\n");
midi_echo1(dat0); break;
case 0xFD: fprintf(stdout, "\tSys RT : reserved 0xFD\n"); break;
case 0xFE:
fprintf(stdout, "\tSys RT : Active Sensing\n");
if (fwd_actsens) midi_echo1(dat0); break;
case 0xFF:
fprintf(stdout, "\tSys RT : MIDI reset\n");
midi_echo1(dat0); break;
default: fprintf(stderr, "ERROR : sysex=%02X - this shouldn't happen!\n", dat0); break;
}
break;
default: fprintf(stderr, "ERROR : value=%02X - this shouldn't happen!\n", dat0); break;
}
}
return rem;
}

int midi_poll()
{
int count = snd_rawmidi_poll_descriptors_count(midi_in);
struct pollfd *pfds = alloca(sizeof(struct pollfd) * count);
snd_rawmidi_poll_descriptors(midi_in, pfds, count);
// Timeout of 0 for immediate check, or -1 to wait
if (poll(pfds, count, 0) > 0) {
unsigned short revents;
snd_rawmidi_poll_descriptors_revents(midi_in, pfds, count, &revents);
if (revents & POLLIN) return 1;
}
return 0;
}

int midi_read(uint8_t *buf, int len)
{
return snd_rawmidi_read(midi_in, buf, len);
}

int midi_write(uint8_t *buf, int len)
{
return snd_rawmidi_write(midi_out, buf, len);
}

void midi_flush()
{
while (midi_poll())
midi_read(&buffer[0], BUFFER_SIZE);
}

void *midi_thread_func(void *arg)
{
uint8_t buffer[256];
while (!thread_should_quit) {
ssize_t n = snd_rawmidi_read(midi_in, buffer, sizeof(buffer));
if (n > 0) midi_parse(buffer, n);
}
return NULL;
}

void run_midi()
{
int result;
result = pthread_create(&midi_thread, NULL, midi_thread_func, NULL);
if (result) {
fprintf(stderr, "Error creating thread\n");
exit(1);
}
}

void stop_midi()
{
thread_should_quit = 1;
sleep(1);
pthread_join(midi_thread, NULL);
}

int main(int argc, char *argv[])
{
int n;
n = midi_open();
if (n < 0) return -1;
midi_flush();
midi_setflags(MF_TX_MODIFIED | MF_EMU_REL_VEL | MF_FIX_NOTEOFF);
#if 0
// using port polling for rx
while (1) {
if (midi_poll()) {
n = midi_read(&buffer[0], BUFFER_SIZE);
midi_parse(&buffer[0], n);
} else {
usleep(250L);
}
}
#else
// using separate thread for rx
run_midi();
fprintf(stdout, "running - send BankHi=127 to exit...\n");
running = 1;
while (running);
fprintf(stdout, "CC(0,0,127) received - exiting\n");
stop_midi();
#endif
midi_close();
return 0;
}
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