Fichiers audio, journal, annales

cours/audio/main.c

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+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <SDL2/SDL.h>
+#include <sndfile.h>
+
+#include "audio.h"
+#include "vcd.h"
+
+const size_t sample_rate = Audio__period;
+
+void die(const char *message) {
+  fprintf(stderr, message);
+  exit(EXIT_FAILURE);
+}
+
+SNDFILE *file_out = NULL;
+
+int main(int argc, char** argv)
+{
+  Audio__main_mem mem;
+  Audio__main_out res;
+  SDL_AudioSpec spec;
+  SDL_AudioDeviceID dev;
+  int opt = -1;
+  bool quiet = false;
+  size_t max_sec = SIZE_MAX;    /* largest value of type size_t */
+  const char *filename = NULL;
+  Uint32 buffered;
+
+  while ((opt = getopt(argc, argv, "ho:qm:t:")) != -1) {
+    switch (opt) {
+    case 'h':
+      printf("Usage: %s OPTIONS\n", argv[0]);
+      printf("Options:\n");
+      printf("  -o <file.wav>   write samples to <file.wav>\n");
+      printf("  -q              do not play sound\n");
+      printf("  -m <sec>        play for <sec> seconds\n");
+      printf("  -t <file.vcd>   dump traces in <file.vcd>\n");
+      printf("  -h              display this message\n");
+      return 0;
+    case 'q':
+      quiet = true;
+      break;
+    case 'o':
+      filename = optarg;
+      break;
+    case 'm':
+      max_sec = atoi(optarg);
+      break;
+    case 't':
+      hept_vcd_init(optarg, VCD_TIME_UNIT_US, 20);
+      break;
+    default:
+      fprintf(stderr, "Unknown option '%c'\n", opt);
+      exit(EXIT_FAILURE);
+    }
+  }
+
+  if (SDL_Init(SDL_INIT_AUDIO) < 0)
+    die("Could not initialize SDL2\n");
+
+  /* Specification of requested output device. */
+  bzero(&spec, sizeof spec);
+  spec.freq = sample_rate;      /* Samples per second */
+  spec.format = AUDIO_F32;      /* Sample format: IEEE-754 32 bits */
+  spec.channels = 2;            /* Two channels */
+  spec.samples = 4096;          /* Buffers sized 4 KiB */
+  spec.callback = NULL;
+
+  if (!(dev = SDL_OpenAudioDevice(NULL, 0, &spec, NULL, 0)))
+    die("Could not open audio device\n");
+
+  if (filename != NULL) {
+    /* Specification of requested output file, if any. */
+    SF_INFO info_out;
+    bzero(&info_out, sizeof info_out);
+    info_out.channels = 2;                              /* Two channels */
+    info_out.samplerate = sample_rate;                  /* Samples per second */
+    info_out.format = SF_FORMAT_WAV | SF_FORMAT_PCM_16; /* File format */
+
+    if (!(file_out = sf_open(filename, SFM_WRITE, &info_out))) {
+      fprintf(stderr, "Could not open WAV file %s for writing\n", argv[1]);
+      SDL_Quit();
+      exit(EXIT_FAILURE);
+    }
+  }
+
+  Audio__main_reset(&mem);
+  float *buffer = calloc(spec.samples, sizeof *buffer);
+  SDL_PauseAudioDevice(dev, 0);
+
+  /* Loop until we've produced the requested amount of samples, that is the
+     duration in seconds multiplied by the number of samples per second. This
+     number of samples shall be sent on each of both stereo channels.
+
+     Each iteration sends spec.samples stereo samples to the audio device,
+     hence we halve it to get the number of generated samples per-channel. */
+  for (size_t samples = 0;
+       samples < max_sec * sample_rate;
+       samples += spec.samples / 2) {
+
+    /* Print sound progress. */
+    printf("\rSent %08zu samples", samples);
+    if (max_sec != SIZE_MAX) {
+      printf(" (%2.0f%)", 100. * (double)samples / (max_sec * sample_rate));
+    }
+    fflush(stdout);
+
+    /* Exit immediately if requested, e.g., the user pressed Ctrl-C. */
+    if (SDL_QuitRequested()) {
+      printf("\n");
+      return 1;
+    }
+
+    /* Step the node as much as necessary to fill a buffer. Each step produces
+       one stereo sample. */
+    for (size_t i = 0; i < spec.samples; i += 2) {
+      Audio__main_step(&res, &mem);
+      buffer[i+0] = res.o.l;
+      buffer[i+1] = res.o.r;
+    }
+
+    /* Send the generated sound to the sound card and/or file. */
+    if (!quiet)
+      SDL_QueueAudio(dev, buffer, spec.samples * sizeof *buffer);
+    if (file_out)
+      sf_writef_float(file_out, buffer, spec.samples / 2);
+
+    /* Throttle queued audio, otherwise we will certainly end up consuming all
+       available memory. */
+    buffered = SDL_GetQueuedAudioSize(dev);
+    while (!quiet && buffered >= 1 << 22) {
+      SDL_Delay(50);
+      buffered = SDL_GetQueuedAudioSize(dev);
+    }
+  }
+  printf("\n");
+
+  /* Wait until the audio buffer is empty. */
+  printf("Waiting for queue flush... "); fflush(stdout);
+  while ((buffered = SDL_GetQueuedAudioSize(dev)) != 0)
+    SDL_Delay(50);
+  printf("done.\n");
+
+  free(buffer);
+  if (file_out)
+    sf_close(file_out);
+  SDL_Quit();
+
+  return 0;
+}