* based on the vplay program by Michael Beck.
*/
+#include <regex.h>
#include <sys/types.h>
#include <dirent.h>
#include <alsa/asoundlib.h>
snd_pcm_t *handle;
/** Determined and set by alsa_open(). */
int bytes_per_frame;
- /** Don't write anything until this time. */
- struct timeval next_chunk;
/** The approximate maximum buffer duration in us. */
unsigned buffer_time;
+ /* Number of frames that fit into the buffer. */
+ unsigned buffer_frames;
/**
* The samplerate given by command line option or the decoder
* of the writer node group.
pad->channels) < 0)
return -E_CHANNEL_COUNT;
if (snd_pcm_hw_params_set_rate_near(pad->handle, hwparams,
- &pad->samplerate, 0) < 0)
+ &pad->samplerate, NULL) < 0)
return -E_SET_RATE;
- err = snd_pcm_hw_params_get_buffer_time_max(hwparams, &pad->buffer_time, 0);
+ err = snd_pcm_hw_params_get_buffer_time_max(hwparams,
+ &pad->buffer_time, NULL);
if (err < 0 || !pad->buffer_time)
return -E_GET_BUFFER_TIME;
PARA_INFO_LOG("buffer time: %d\n", pad->buffer_time);
if (snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams,
- &pad->buffer_time, 0) < 0)
+ &pad->buffer_time, NULL) < 0)
return -E_SET_BUFFER_TIME;
if (snd_pcm_hw_params(pad->handle, hwparams) < 0)
return -E_HW_PARAMS;
- snd_pcm_hw_params_get_period_size(hwparams, &period_size, 0);
+ snd_pcm_hw_params_get_period_size(hwparams, &period_size, NULL);
snd_pcm_hw_params_get_buffer_size(hwparams, &buffer_size);
PARA_INFO_LOG("buffer size: %lu, period_size: %lu\n", buffer_size,
period_size);
PARA_INFO_LOG("bytes per frame: %d\n", pad->bytes_per_frame);
if (snd_pcm_nonblock(pad->handle, 1))
PARA_ERROR_LOG("failed to set nonblock mode\n");
+ pad->buffer_frames = 1000 * pad->buffer_time / pad->samplerate;
+ PARA_INFO_LOG("max buffered frames: %d\n", pad->buffer_frames);
return 1;
}
else
pad->channels = conf->channels_arg;
PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels, pad->samplerate);
- tv_add(now, &(struct timeval){0, 100 * 1000}, &pad->next_chunk);
return 1;
}
{
struct private_alsa_write_data *pad = wn->private_data;
struct writer_node_group *wng = wn->wng;
- struct timeval diff;
+ struct timeval tv;
+ snd_pcm_sframes_t avail, underrun;
- if (!*wng->loaded)
+ if (!pad->handle)
return 1;
- if (tv_diff(now, &pad->next_chunk, &diff) < 0) {
- if (tv_diff(&s->timeout, &diff, NULL) > 0)
- s->timeout = diff;
- } else {
- s->timeout.tv_sec = 0;
- s->timeout.tv_usec = 1;
- }
+ if (*wng->loaded - wn->written < pad->bytes_per_frame)
+ return 1;
+ /*
+ * Data is available to be written to the alsa handle. Compute number
+ * of milliseconds until next buffer underrun would occur.
+ *
+ * snd_pcm_avail_update() updates the current available count of
+ * samples for writing. It is a light method to obtain current stream
+ * position, because it does not require the user <-> kernel context
+ * switch, but the value is less accurate, because ring buffer pointers
+ * are updated in kernel drivers only when an interrupt occurs.
+ */
+ avail = snd_pcm_avail_update(pad->handle);
+ if (avail < 0)
+ avail = 0;
+ underrun = (pad->buffer_frames - avail) * pad->buffer_time
+ / pad->buffer_frames / 1000;
+ if (underrun < 50)
+ underrun = 50;
+ underrun -= 50;
+ ms2tv(underrun, &tv);
+ if (tv_diff(&s->timeout, &tv, NULL) > 0)
+ s->timeout = tv;
return 1;
}
struct writer_node_group *wng = wn->wng;
size_t bytes = *wng->loaded - wn->written;
unsigned char *data = (unsigned char*)*wng->bufp + wn->written;
- struct timeval tv;
snd_pcm_sframes_t ret, frames, avail;
if (*wng->input_error < 0 && (!pad->handle || bytes < pad->bytes_per_frame)) {
}
if (!bytes) /* no data available */
return 0;
- if (tv_diff(now, &pad->next_chunk, NULL) < 0)
- return 0;
if (!pad->handle) {
int err = alsa_init(pad, wn->conf);
if (err < 0)
return 0;
avail = snd_pcm_avail_update(pad->handle);
if (avail <= 0)
- goto delay;
+ return 0;
frames = PARA_MIN(frames, avail);
ret = snd_pcm_writei(pad->handle, data, frames);
- if (ret < 0) {
- PARA_WARNING_LOG("%s\n", snd_strerror(-ret));
- if (ret == -EPIPE) {
- snd_pcm_prepare(pad->handle);
- return 0;
- }
- if (ret == -EAGAIN)
- goto delay;
- return -E_ALSA_WRITE;
+ if (ret >= 0) {
+ wn->written += ret * pad->bytes_per_frame;
+ return 1;
}
- wn->written += ret * pad->bytes_per_frame;
- return 1;
-delay:
- /* wait until 50% buffer space is available */
- ms2tv(pad->buffer_time / 2000, &tv);
- tv_add(now, &tv, &pad->next_chunk);
- return 0;
+ PARA_WARNING_LOG("%s\n", snd_strerror(-ret));
+ if (ret == -EPIPE) {
+ snd_pcm_prepare(pad->handle);
+ return 0;
+ }
+ if (ret == -EAGAIN)
+ return 0;
+ return -E_ALSA_WRITE;
}
static void alsa_close(struct writer_node *wn)
projects / paraslash.git / blobdiff