Commit ccb049c1 authored by Rémi Denis-Courmont's avatar Rémi Denis-Courmont
Browse files

PulseAudio: resync and keep in sync with PulseAudio resampling

parent e3133936
......@@ -66,6 +66,9 @@ struct aout_sys_t
pa_context *context; /**< PulseAudio connection context */
pa_volume_t base_volume; /**< 0dB reference volume */
pa_cvolume cvolume; /**< actual sink input volume */
mtime_t pts; /**< Play time of buffer write offset */
mtime_t desync; /**< Measured desynchronization */
unsigned rate; /**< Current stream sample rate */
};
/*** Sink ***/
......@@ -109,6 +112,20 @@ static void sink_info_cb(pa_context *c, const pa_sink_info *i, int eol,
}
/*** Stream helpers ***/
static void stream_reset_sync(pa_stream *s, aout_instance_t *aout)
{
aout_sys_t *sys = aout->output.p_sys;
const unsigned rate = aout->output.output.i_rate;
sys->pts = VLC_TS_INVALID;
sys->desync = 0;
pa_operation *op = pa_stream_update_sample_rate(s, rate, NULL, NULL);
if (unlikely(op == NULL))
return;
pa_operation_unref(op);
sys->rate = rate;
}
static void stream_state_cb(pa_stream *s, void *userdata)
{
switch (pa_stream_get_state(s)) {
......@@ -122,6 +139,83 @@ static void stream_state_cb(pa_stream *s, void *userdata)
(void) userdata;
}
/* Latency management and lip synchronization */
/* Values from EBU R37 */
#define AOUT_EARLY_TOLERANCE 40000
#define AOUT_LATE_TOLERANCE 60000
static void stream_latency_cb(pa_stream *s, void *userdata)
{
aout_instance_t *aout = userdata;
aout_sys_t *sys = aout->output.p_sys;
mtime_t delta, change;
if (sys->pts == VLC_TS_INVALID)
{
msg_Dbg(aout, "missing latency from input");
return;
}
/* Compute lip desynchronization */
{
pa_usec_t latency;
int negative;
if (pa_stream_get_latency(s, &latency, &negative)) {
vlc_pa_error(aout, "missing latency", sys->context);
return;
}
delta = sys->pts - mdate();
if (unlikely(negative))
delta += latency;
else
delta -= latency;
}
change = delta - sys->desync;
sys->desync = delta;
//msg_Dbg(aout, "desync: %+"PRId64" us (variation: %+"PRId64" us)",
// delta, change);
/* Compute playback sample rate */
const unsigned inrate = aout->output.output.i_rate;
/* NOTE: AOUT_MAX_RESAMPLING (10%) is way too high... */
const int limit = inrate >> 6;
if (delta < -AOUT_LATE_TOLERANCE) {
msg_Warn(aout, "too late by %"PRId64" us", -delta);
if (change < 0)
delta += change; /* be more severe if really out of sync */
} else if (delta > +AOUT_EARLY_TOLERANCE) {
msg_Warn(aout, "too early by %"PRId64" us", delta);
if (change > 0)
delta += change;
}
/* This is empirical. Feel free to define something smarter. */
int outrate = inrate * delta / -(CLOCK_FREQ * 10);
if (16 * abs(outrate) < limit)
outrate = inrate; /* favor native rate to avoid resampling */
else if (outrate > limit)
outrate = inrate + limit;
else if (outrate < -limit)
outrate = inrate - limit;
else
outrate += inrate;
/* Apply adjusted sample rate */
if (outrate == (int)sys->rate)
return;
pa_operation *op = pa_stream_update_sample_rate(s, outrate, NULL, NULL);
if (unlikely(op == NULL)) {
vlc_pa_error(aout, "cannot change sample rate", sys->context);
return;
}
pa_operation_unref(op);
msg_Dbg(aout, "changed sample rate to %d Hz", outrate);
sys->rate = outrate;
}
static void stream_moved_cb(pa_stream *s, void *userdata)
{
aout_instance_t *aout = userdata;
......@@ -162,7 +256,7 @@ static void stream_suspended_cb(pa_stream *s, void *userdata)
aout_instance_t *aout = userdata;
msg_Dbg(aout, "suspended");
(void) s;
stream_reset_sync(s, aout);
}
static void stream_underflow_cb(pa_stream *s, void *userdata)
......@@ -174,6 +268,7 @@ static void stream_underflow_cb(pa_stream *s, void *userdata)
op = pa_stream_cork(s, 1, NULL, NULL);
if (op != NULL)
pa_operation_unref(op);
stream_reset_sync(s, aout);
}
static int stream_wait(pa_stream *stream)
......@@ -275,8 +370,10 @@ static void Play(aout_instance_t *aout)
msg_Dbg(aout, "prepending %zu zeroes", nb);
if (likely(zeroes != NULL))
#if 1 /* Fault injection: remove this to be too early */
if (pa_stream_write(s, zeroes, nb * size, free, 0,
PA_SEEK_RELATIVE) < 0)
#endif
free(zeroes);
}
......@@ -289,11 +386,11 @@ static void Play(aout_instance_t *aout)
msg_Dbg(aout, "uncorking");
}
#if 0 /* Fault injector to test underrun recovery */
#if 0 /* Fault injector to be too late / test underrun recovery */
static unsigned u = 0;
if ((++u % 500) == 0) {
msg_Err(aout, "fault injection");
msleep(CLOCK_FREQ*2);
pa_operation_unref(pa_stream_flush(s, NULL, NULL));
}
#endif
......@@ -301,6 +398,7 @@ static void Play(aout_instance_t *aout)
vlc_pa_error(aout, "cannot write", sys->context);
block_Release(block);
}
sys->pts = pts;
vlc_pa_unlock();
}
......@@ -321,6 +419,7 @@ static void Pause(aout_instance_t *aout, bool b_paused, mtime_t i_date)
pa_operation *op = pa_stream_cork(s, 1, NULL, NULL);
if (op != NULL)
pa_operation_unref(op);
stream_reset_sync(s, aout);
vlc_pa_unlock();
(void) i_date;
......@@ -494,7 +593,8 @@ static int Open(vlc_object_t *obj)
/* Stream parameters */
const pa_stream_flags_t flags = PA_STREAM_START_CORKED
//| PA_STREAM_INTERPOLATE_TIMING
| PA_STREAM_AUTO_TIMING_UPDATE;
| PA_STREAM_AUTO_TIMING_UPDATE
| PA_STREAM_VARIABLE_RATE;
const uint32_t byterate = pa_bytes_per_second(&ss);
struct pa_buffer_attr attr;
......@@ -525,6 +625,9 @@ static int Open(vlc_object_t *obj)
aout->output.p_sys = sys;
sys->stream = NULL;
sys->context = ctx;
sys->pts = VLC_TS_INVALID;
sys->desync = 0;
sys->rate = ss.rate;
/* Channel volume */
sys->base_volume = PA_VOLUME_NORM;
......@@ -539,6 +642,7 @@ static int Open(vlc_object_t *obj)
}
sys->stream = s;
pa_stream_set_state_callback(s, stream_state_cb, NULL);
pa_stream_set_latency_update_callback(s, stream_latency_cb, aout);
pa_stream_set_moved_callback(s, stream_moved_cb, aout);
pa_stream_set_overflow_callback(s, stream_overflow_cb, aout);
pa_stream_set_started_callback(s, stream_started_cb, aout);
......
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