+ {
+ snd_pcm_t *pcm;
+ snd_pcm_hw_params_t *hwparams;
+ snd_pcm_sw_params_t *swparams;
+ /* Only support one format for now */
+ const int sample_format = SND_PCM_FORMAT_S16_BE;
+ unsigned rate = 44100;
+ const int channels = 2;
+ const int samplesize = channels * sizeof(uint16_t);
+ snd_pcm_uframes_t pcm_bufsize = MAXSAMPLES * samplesize * 3;
+ /* If we can write more than this many samples we'll get a wakeup */
+ const int avail_min = 256;
+ snd_pcm_sframes_t frames_written;
+ size_t samples_written;
+ int prepared = 1;
+ int err;
+ int infilling = 0, escape = 0;
+ time_t logged, now;
+ uint32_t packet_start, packet_end;
+
+ /* Open ALSA */
+ if((err = snd_pcm_open(&pcm,
+ device ? device : "default",
+ SND_PCM_STREAM_PLAYBACK,
+ SND_PCM_NONBLOCK)))
+ fatal(0, "error from snd_pcm_open: %d", err);
+ /* Set up 'hardware' parameters */
+ snd_pcm_hw_params_alloca(&hwparams);
+ if((err = snd_pcm_hw_params_any(pcm, hwparams)) < 0)
+ fatal(0, "error from snd_pcm_hw_params_any: %d", err);
+ if((err = snd_pcm_hw_params_set_access(pcm, hwparams,
+ SND_PCM_ACCESS_RW_INTERLEAVED)) < 0)
+ fatal(0, "error from snd_pcm_hw_params_set_access: %d", err);
+ if((err = snd_pcm_hw_params_set_format(pcm, hwparams,
+ sample_format)) < 0)
+ fatal(0, "error from snd_pcm_hw_params_set_format (%d): %d",
+ sample_format, err);
+ if((err = snd_pcm_hw_params_set_rate_near(pcm, hwparams, &rate, 0)) < 0)
+ fatal(0, "error from snd_pcm_hw_params_set_rate (%d): %d",
+ rate, err);
+ if((err = snd_pcm_hw_params_set_channels(pcm, hwparams,
+ channels)) < 0)
+ fatal(0, "error from snd_pcm_hw_params_set_channels (%d): %d",
+ channels, err);
+ if((err = snd_pcm_hw_params_set_buffer_size_near(pcm, hwparams,
+ &pcm_bufsize)) < 0)
+ fatal(0, "error from snd_pcm_hw_params_set_buffer_size (%d): %d",
+ MAXSAMPLES * samplesize * 3, err);
+ if((err = snd_pcm_hw_params(pcm, hwparams)) < 0)
+ fatal(0, "error calling snd_pcm_hw_params: %d", err);
+ /* Set up 'software' parameters */
+ snd_pcm_sw_params_alloca(&swparams);
+ if((err = snd_pcm_sw_params_current(pcm, swparams)) < 0)
+ fatal(0, "error calling snd_pcm_sw_params_current: %d", err);
+ if((err = snd_pcm_sw_params_set_avail_min(pcm, swparams, avail_min)) < 0)
+ fatal(0, "error calling snd_pcm_sw_params_set_avail_min %d: %d",
+ avail_min, err);
+ if((err = snd_pcm_sw_params(pcm, swparams)) < 0)
+ fatal(0, "error calling snd_pcm_sw_params: %d", err);
+
+ /* Ready to go */
+
+ time(&logged);
+ pthread_mutex_lock(&lock);
+ for(;;) {
+ /* Wait for the buffer to fill up a bit */
+ logged = now;
+ info("%lu samples in buffer (%lus)", nsamples,
+ nsamples / (44100 * 2));
+ info("Buffering...");
+ while(nsamples < readahead)
+ pthread_cond_wait(&cond, &lock);
+ if(!prepared) {
+ if((err = snd_pcm_prepare(pcm)))
+ fatal(0, "error calling snd_pcm_prepare: %d", err);
+ prepared = 1;
+ }
+ assert(sequence != -1);
+ /* Start at the first available packet */
+ next_timestamp = packets[sequence]->timestamp;
+ active = 1;
+ infilling = 0;
+ escape = 0;
+ logged = now;
+ info("%lu samples in buffer (%lus)", nsamples,
+ nsamples / (44100 * 2));
+ info("Playing...");
+ /* Wait until the buffer empties out */
+ while(nsamples >= minbuffer && !escape) {
+ time(&now);
+ if(now > logged + 10) {
+ logged = now;
+ info("%lu samples in buffer (%lus)", nsamples,
+ nsamples / (44100 * 2));
+ }
+ if(packets
+ && ge(next_timestamp, packets->timestamp + packets->nsamples)) {
+ info("dropping buffered past packet %"PRIx32" < %"PRIx32,
+ packets->timestamp, next_timestamp);
+ drop_first_packet();
+ continue;
+ }
+ /* Wait for ALSA to ask us for more data */
+ pthread_mutex_unlock(&lock);
+ write(2, ".", 1); /* TODO remove me sometime */
+ switch(err = snd_pcm_wait(pcm, -1)) {
+ case 0:
+ info("snd_pcm_wait timed out");
+ break;
+ case 1:
+ break;
+ default:
+ fatal(0, "snd_pcm_wait returned %d", err);
+ }
+ pthread_mutex_lock(&lock);
+ /* ALSA is ready for more data */
+ packet_start = packets->timestamp;
+ packet_end = packets->timestamp + packets->nsamples;
+ if(ge(next_timestamp, packet_start)
+ && lt(next_timestamp, packet_end)) {
+ /* The target timestamp is somewhere in this packet */
+ const uint32_t offset = next_timestamp - packets->timestamp;
+ const uint32_t samples_available = (packets->timestamp + packets->nsamples) - next_timestamp;
+ const size_t frames_available = samples_available / 2;
+
+ frames_written = snd_pcm_writei(pcm,
+ packets->samples_raw + offset,
+ frames_available);
+ if(frames_written < 0) {
+ switch(frames_written) {
+ case -EAGAIN:
+ info("snd_pcm_wait() returned but we got -EAGAIN!");
+ break;
+ case -EPIPE:
+ error(0, "error calling snd_pcm_writei: %ld",
+ (long)frames_written);
+ escape = 1;
+ break;
+ default:
+ fatal(0, "error calling snd_pcm_writei: %ld",
+ (long)frames_written);
+ }
+ } else {
+ samples_written = frames_written * 2;
+ next_timestamp += samples_written;
+ if(ge(next_timestamp, packet_end))
+ drop_first_packet();
+ infilling = 0;
+ }
+ } else {
+ /* We don't have anything to play! We'd better play some 0s. */
+ static const uint16_t zeros[INFILL_SAMPLES];
+ size_t samples_available = INFILL_SAMPLES, frames_available;
+
+ /* If the maximum infill would take us past the start of the next
+ * packet then we truncate the infill to the right amount. */
+ if(lt(packets->timestamp,
+ next_timestamp + samples_available))
+ samples_available = packets->timestamp - next_timestamp;
+ if((int)samples_available < 0) {
+ info("packets->timestamp: %"PRIx32" next_timestamp: %"PRIx32" next+max: %"PRIx32" available: %"PRIx32,
+ packets->timestamp, next_timestamp,
+ next_timestamp + INFILL_SAMPLES, samples_available);
+ }
+ frames_available = samples_available / 2;
+ if(!infilling) {
+ info("Infilling %d samples, next=%"PRIx32" packet=[%"PRIx32",%"PRIx32"]",
+ samples_available, next_timestamp,
+ packets->timestamp, packets->timestamp + packets->nsamples);
+ //infilling++;
+ }
+ frames_written = snd_pcm_writei(pcm,
+ zeros,
+ frames_available);
+ if(frames_written < 0) {
+ switch(frames_written) {
+ case -EAGAIN:
+ info("snd_pcm_wait() returned but we got -EAGAIN!");
+ break;
+ case -EPIPE:
+ error(0, "error calling snd_pcm_writei: %ld",
+ (long)frames_written);
+ escape = 1;
+ break;
+ default:
+ fatal(0, "error calling snd_pcm_writei: %ld",
+ (long)frames_written);
+ }
+ } else {
+ samples_written = frames_written * 2;
+ next_timestamp += samples_written;
+ }
+ }
+ }
+ active = 0;
+ /* We stop playing for a bit until the buffer re-fills */
+ pthread_mutex_unlock(&lock);
+ if((err = snd_pcm_nonblock(pcm, 0)))
+ fatal(0, "error calling snd_pcm_nonblock: %d", err);
+ if(escape) {
+ if((err = snd_pcm_drop(pcm)))
+ fatal(0, "error calling snd_pcm_drop: %d", err);
+ escape = 0;
+ } else
+ if((err = snd_pcm_drain(pcm)))
+ fatal(0, "error calling snd_pcm_drain: %d", err);
+ if((err = snd_pcm_nonblock(pcm, 1)))
+ fatal(0, "error calling snd_pcm_nonblock: %d", err);
+ prepared = 0;
+ pthread_mutex_lock(&lock);
+ }
+
+ }