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ext/alsa/: Use alsa trigger_tstamp to get the timestamp of the first sample in the buffer for more precise sync. Some...

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Original commit message from CVS:
* ext/alsa/gstalsa.c: (gst_alsa_start), (gst_alsa_xrun_recovery):
* ext/alsa/gstalsa.h:
* ext/alsa/gstalsasrc.c: (gst_alsa_src_init),
(gst_alsa_src_update_avail), (gst_alsa_src_loop):
Use alsa trigger_tstamp to get the timestamp of the first
sample in the buffer for more precise sync. Some cleanups.
This commit is contained in:
Wim Taymans 2004-06-24 12:53:17 +00:00
parent 796529c197
commit 1bb09c4352
4 changed files with 47 additions and 27 deletions
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9
ChangeLog
View file

@ -1,3 +1,12 @@
2004-06-24 Wim Taymans <wim@fluendo.com>
* ext/alsa/gstalsa.c: (gst_alsa_start), (gst_alsa_xrun_recovery):
* ext/alsa/gstalsa.h:
* ext/alsa/gstalsasrc.c: (gst_alsa_src_init),
(gst_alsa_src_update_avail), (gst_alsa_src_loop):
Use alsa trigger_tstamp to get the timestamp of the first
sample in the buffer for more precise sync. Some cleanups.
2004-06-24 Wim Taymans <wim@fluendo.com>
* gst/audiorate/gstaudiorate.c: (gst_audiorate_link),

29
ext/alsa/gstalsa.c
View file

@ -1203,8 +1203,6 @@ gst_alsa_pcm_wait (GstAlsa * this)
inline gboolean
gst_alsa_start (GstAlsa * this)
{
GstClockTime elemnow;
GST_DEBUG ("Setting state to RUNNING");
switch (snd_pcm_state (this->handle)) {
@ -1215,13 +1213,7 @@ gst_alsa_start (GstAlsa * this)
ERROR_CHECK (snd_pcm_prepare (this->handle), "error preparing: %s");
case SND_PCM_STATE_SUSPENDED:
case SND_PCM_STATE_PREPARED:
/* The strategy to recover the timestamps from the xrun is to take the
* current element time and pretend we just sent all the samples up to
* that time. This will result in an offset discontinuity in the next
* buffer along with the correct timestamp on that buffer, we only
* update the capture timestamps */
elemnow = gst_element_get_time (GST_ELEMENT (this));
this->captured = gst_alsa_timestamp_to_samples (this, elemnow);
this->captured = 0;
ERROR_CHECK (snd_pcm_start (this->handle), "error starting playback: %s");
break;
case SND_PCM_STATE_PAUSED:
@ -1254,6 +1246,11 @@ gst_alsa_xrun_recovery (GstAlsa * this)
GST_ERROR_OBJECT (this, "status error: %s", snd_strerror (err));
if (snd_pcm_status_get_state (status) == SND_PCM_STATE_XRUN) {
struct timeval now, diff, tstamp;
gettimeofday (&now, 0);
snd_pcm_status_get_trigger_tstamp (status, &tstamp);
timersub (&now, &tstamp, &diff);
/* if we're allowed to recover, ... */
if (this->autorecover) {
@ -1269,8 +1266,12 @@ gst_alsa_xrun_recovery (GstAlsa * this)
}
/* prepare the device again */
if ((err = snd_pcm_prepare (this->handle)) < 0) {
GST_ERROR_OBJECT (this, "prepare error: %s", snd_strerror (err));
if ((err = snd_pcm_drop (this->handle)) < 0) {
GST_ERROR_OBJECT (this, "drop error: %s", snd_strerror (err));
return FALSE;
}
if ((err = snd_pcm_drain (this->handle)) < 0) {
GST_ERROR_OBJECT (this, "drop error: %s", snd_strerror (err));
return FALSE;
}
if (!gst_alsa_start (this)) {
@ -1278,8 +1279,10 @@ gst_alsa_xrun_recovery (GstAlsa * this)
("Error starting audio after xrun"));
return FALSE;
}
GST_DEBUG_OBJECT (this, "XRun!!!! pretending we captured %lld samples",
this->captured);
GST_DEBUG_OBJECT (this, "XRun!!!! of at least %.3f msecs, "
"pretending we captured %lld samples",
diff.tv_sec * 1000 + diff.tv_usec / 1000.0, this->captured);
} else {
if (!(gst_alsa_stop_audio (this) && gst_alsa_start_audio (this))) {
GST_ELEMENT_ERROR (this, RESOURCE, FAILED, (NULL),

1
ext/alsa/gstalsa.h
View file

@ -156,7 +156,6 @@ struct _GstAlsa {
/* clocking */
GstAlsaClock * clock; /* our provided clock */
GstClockTime clock_base;
snd_pcm_uframes_t played; /* samples transmitted since last sync
This thing actually is our master clock.
We will event insert silent samples or

35
ext/alsa/gstalsasrc.c
View file

@ -363,13 +363,6 @@ gst_alsa_src_loop (GstElement * element)
return;
}
}
if (this->clock_base == GST_CLOCK_TIME_NONE) {
GstClockTime now;
now = gst_element_get_time (element);
this->clock_base = gst_alsa_src_get_time (this);
this->captured = gst_alsa_timestamp_to_samples (this, now);
}
/* the cast to long is explicitly needed;
* with avail = -32 and period_size = 100, avail < period_size is false */
@ -393,8 +386,18 @@ gst_alsa_src_loop (GstElement * element)
{
gint outsize;
GstClockTime outtime, outdur, outreal, outideal;
gint64 diff;
GstClockTime outtime, outdur, outreal, outideal, startalsa, outalsa;
gint64 diff, offset;
snd_pcm_status_t *status;
struct timeval tstamp;
int err;
snd_pcm_status_alloca (&status);
if ((err = snd_pcm_status (this->handle, status)) < 0)
GST_ERROR_OBJECT (this, "status error: %s", snd_strerror (err));
offset = this->captured;
/* duration of buffer is just the time of the samples */
outdur = gst_alsa_samples_to_timestamp (this, copied);
@ -403,19 +406,25 @@ gst_alsa_src_loop (GstElement * element)
* what is now in the buffer */
outreal = gst_element_get_time (GST_ELEMENT (this)) - outdur;
/* ideal time is counting samples */
outideal = gst_alsa_samples_to_timestamp (this, this->captured);
outideal = gst_alsa_samples_to_timestamp (this, offset);
snd_pcm_status_get_trigger_tstamp (status, &tstamp);
startalsa = GST_TIMEVAL_TO_TIME (tstamp) - element->base_time;
outalsa = startalsa + outideal;
outsize = gst_alsa_samples_to_bytes (this, copied);
outtime = GST_CLOCK_TIME_NONE;
if (GST_ELEMENT_CLOCK (this)) {
if (GST_CLOCK (GST_ALSA (this)->clock) == GST_ELEMENT_CLOCK (this)) {
outtime = outideal;
outtime = outalsa;
diff = outideal - outreal;
GST_DEBUG_OBJECT (this, "ideal %lld, real %lld, diff %lld\n", outideal,
outreal, diff);
offset = gst_alsa_timestamp_to_samples (this, outtime);
} else {
outtime = outreal;
offset = gst_alsa_timestamp_to_samples (this, outtime);
}
}
@ -430,8 +439,8 @@ gst_alsa_src_loop (GstElement * element)
GST_BUFFER_TIMESTAMP (src->buf[i]) = outtime;
GST_BUFFER_DURATION (src->buf[i]) = outdur;
GST_BUFFER_OFFSET (src->buf[i]) = this->captured;
GST_BUFFER_OFFSET_END (src->buf[i]) = this->captured + copied;
GST_BUFFER_OFFSET (src->buf[i]) = offset;
GST_BUFFER_OFFSET_END (src->buf[i]) = offset + copied;
buf = src->buf[i];
src->buf[i] = NULL;