/**
* Rearranges audio blocks in correct number of samples.
* @note (FIXME) This is left here for historical reasons. It belongs in the
* output code. Besides, this operation should be avoided if possible.
*/
static block_t *aout_OutputSlice (audio_output_t *p_aout)
{
aout_packet_t *p = aout_packet (p_aout);
aout_fifo_t *p_fifo = &p->partial;
const unsigned samples = p->samples;
assert( samples > 0 );
/* Retrieve the date of the next buffer. */
date_t exact_start_date = p->fifo.end_date;
mtime_t start_date = date_Get( &exact_start_date );
/* Check if there is enough data to slice a new buffer. */
aout_buffer_t *p_buffer = p_fifo->p_first;
if( p_buffer == NULL )
return NULL;
/* Find the earliest start date available. */
if ( start_date == VLC_TS_INVALID )
{
start_date = p_buffer->i_pts;
date_Set( &exact_start_date, start_date );
}
/* Compute the end date for the new buffer. */
mtime_t end_date = date_Increment( &exact_start_date, samples );
/* Check that we have enough samples (TODO merge with next loop). */
for( unsigned available = 0; available < samples; )
{
p_buffer = p_buffer->p_next;
if( p_buffer == NULL )
return NULL;
available += p_buffer->i_nb_samples;
}
if( AOUT_FMT_LINEAR( &p_aout->format ) )
{
const unsigned framesize = p_aout->format.i_bytes_per_frame;
/* Build packet with adequate number of samples */
unsigned needed = samples * framesize;
p_buffer = block_Alloc( needed );
if( unlikely(p_buffer == NULL) )
/* XXX: should free input buffers */
return NULL;
p_buffer->i_nb_samples = samples;
for( uint8_t *p_out = p_buffer->p_buffer; needed > 0; )
{
aout_buffer_t *p_inbuf = p_fifo->p_first;
if( unlikely(p_inbuf == NULL) )
{
msg_Err( p_aout, "packetization error" );
vlc_memset( p_out, 0, needed );
break;
}
const uint8_t *p_in = p_inbuf->p_buffer;
size_t avail = p_inbuf->i_nb_samples * framesize;
if( avail > needed )
{
vlc_memcpy( p_out, p_in, needed );
p_fifo->p_first->p_buffer += needed;
p_fifo->p_first->i_buffer -= needed;
needed /= framesize;
p_fifo->p_first->i_nb_samples -= needed;
mtime_t t = needed * CLOCK_FREQ / p_aout->format.i_rate;
p_fifo->p_first->i_pts += t;
p_fifo->p_first->i_length -= t;
break;
}
vlc_memcpy( p_out, p_in, avail );
needed -= avail;
p_out += avail;
/* Next buffer */
aout_BufferFree( aout_FifoPop( p_fifo ) );
}
}
else
p_buffer = aout_FifoPop( p_fifo );
p_buffer->i_pts = start_date;
p_buffer->i_length = end_date - start_date;
return p_buffer;
}
/**
* Dequeues the next audio packet (a.k.a. audio fragment).
* The audio output plugin must first call aout_PacketPlay() to queue the
* decoded audio samples. Typically, audio_output_t.pf_play is set to, or calls
* aout_PacketPlay().
* @note This function is considered legacy. Please do not use this function in
* new audio output plugins.
* @param p_aout audio output instance
* @param start_date expected PTS of the audio packet
*/
block_t *aout_PacketNext (audio_output_t *p_aout, mtime_t start_date)
{
aout_packet_t *p = aout_packet (p_aout);
aout_fifo_t *p_fifo = &p->fifo;
block_t *p_buffer;
const bool b_can_sleek = !AOUT_FMT_LINEAR(&p_aout->format);
const mtime_t now = mdate ();
const mtime_t threshold =
(b_can_sleek ? start_date : now) - AOUT_MAX_PTS_DELAY;
vlc_mutex_lock( &p->lock );
if( p->pause_date != VLC_TS_INVALID )
goto out; /* paused: do not dequeue buffers */
for (;;)
{
p_buffer = p_fifo->p_first;
if (p_buffer == NULL)
goto out; /* nothing to play */
if (p_buffer->i_pts >= threshold)
break;
/* Drop the audio sample if the audio output is really late.
* In the case of b_can_sleek, we don't use a resampler so we need to
* be a lot more severe. */
msg_Dbg (p_aout, "audio output is too slow (%"PRId64" us): "
" trashing %"PRId64" us", threshold - p_buffer->i_pts,
p_buffer->i_length);
block_Release (aout_FifoPop (p_fifo));
}
mtime_t delta = start_date - p_buffer->i_pts;
/* This assumes that all buffers have the same duration. This is true
* since aout_PacketPlay() (aout_OutputSlice()) is used. */
if (0 >= delta + p_buffer->i_length)
{
if (!p->starving)
{
msg_Dbg (p_aout, "audio output is starving (%"PRId64"), "
"playing silence", delta);
p->starving = true;
}
goto out; /* nothing to play _yet_ */
}
p->starving = false;
p_buffer = aout_FifoPop( p_fifo );
if (!b_can_sleek
&& (delta < -AOUT_MAX_PTS_ADVANCE || AOUT_MAX_PTS_DELAY < delta))
{
msg_Warn (p_aout, "audio output out of sync, "
"adjusting dates (%"PRId64" us)", delta);
aout_FifoMoveDates (&p->partial, delta);
aout_FifoMoveDates (p_fifo, delta);
p->time_report = delta;
}
vlc_mutex_unlock( &p->lock );
return p_buffer;
out:
vlc_mutex_unlock( &p->lock );
return NULL;
}
