PulseAudio example

PulseAudio APIs

pa_simple_new
pa_simple_write
pa_simple_drain
pa_simple_free
https://freedesktop.org/software/pulseaudio/doxygen/examples.html

build command

gcc -o pulse pulse.c `pkg-config --cflags --libs libpulse-simple`

source

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <pulse/simple.h>
#include <pulse/error.h>
#define BUFSIZE 1024
int main(int argc, char* argv[]) {
  /* The Sample format to use */
  static const pa_sample_spec ss = {
      .format = PA_SAMPLE_S16LE, .rate = 44100, .channels = 2};
  pa_simple* s = NULL;
  int ret = 1;
  int error;
  /* replace STDIN with the specified file if needed */
  if (argc > 1) {
    int fd;
    if ((fd = open(argv[1], O_RDONLY)) < 0) {
      fprintf(stderr, __FILE__ ": open() failed: %s\n", strerror(errno));
      goto finish;
    }
    if (dup2(fd, STDIN_FILENO) < 0) {
      fprintf(stderr, __FILE__ ": dup2() failed: %s\n", strerror(errno));
      goto finish;
    }
    close(fd);
  }
  /* Create a new playback stream */
  if (!(s = pa_simple_new(NULL, argv[0], PA_STREAM_PLAYBACK, NULL, "playback",
                          &ss, NULL, NULL, &error))) {
    fprintf(stderr, __FILE__ ": pa_simple_new() failed: %s\n",
            pa_strerror(error));
    goto finish;
  }
  for (;;) {
    uint8_t buf[BUFSIZE];
    ssize_t r;
#if 0
        pa_usec_t latency;
        if ((latency = pa_simple_get_latency(s, &error)) == (pa_usec_t) -1) {
            fprintf(stderr, __FILE__": pa_simple_get_latency() failed: %s\n", pa_strerror(error));
            goto finish;
        }
        fprintf(stderr, "%0.0f usec    \r", (float)latency);
#endif
    /* Read some data ... */
    if ((r = read(STDIN_FILENO, buf, sizeof(buf))) <= 0) {
      if (r == 0) /* EOF */
        break;
      fprintf(stderr, __FILE__ ": read() failed: %s\n", strerror(errno));
      goto finish;
    }
    /* ... and play it */
    if (pa_simple_write(s, buf, (size_t)r, &error) < 0) {
      fprintf(stderr, __FILE__ ": pa_simple_write() failed: %s\n",
              pa_strerror(error));
      goto finish;
    }
  }
  /* Make sure that every single sample was played */
  if (pa_simple_drain(s, &error) < 0) {
    fprintf(stderr, __FILE__ ": pa_simple_drain() failed: %s\n",
            pa_strerror(error));
    goto finish;
  }
  ret = 0;
finish:
  if (s)
    pa_simple_free(s);
  return ret;
}

 

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