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a/v sync cleanups 

git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@10705 b3059339-0415-0410-9bf9-f77b7e298cf2
This commit is contained in:
henry 2003-08-27 09:23:39 +00:00
parent 28f695ad5a
commit ad568e6c40
1 changed files with 21 additions and 12 deletions
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33
libmpdemux/tvi_v4l2.c
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@ -1498,7 +1498,8 @@ static int get_video_framesize(priv_t *priv)
return priv->format.fmt.pix.sizeimage;
}
/*
//#define DOUBLESPEED
#ifdef DOUBLESPEED
// for testing purposes only
static void read_doublespeed(priv_t *priv)
{
@ -1518,7 +1519,7 @@ static void read_doublespeed(priv_t *priv)
}
}
*/
#endif
static void *audio_grabber(void *data)
{
@ -1537,10 +1538,12 @@ static void *audio_grabber(void *data)
for (; !priv->shutdown;)
{
// read_doublespeed(priv);
#ifdef DOUBLESPEED
read_doublespeed(priv);
#else
if (audio_in_read_chunk(&priv->audio_in, priv->audio_ringbuffer+priv->audio_tail*priv->audio_in.blocksize) < 0)
continue;
#endif
pthread_mutex_lock(&priv->skew_mutex);
if (priv->first_frame == 0) {
// there is no first frame yet (unlikely to happen)
@ -1558,32 +1561,38 @@ static void *audio_grabber(void *data)
// fprintf(stderr, "spb = %lf, bs = %d, skew = %lf\n", priv->audio_secs_per_block, priv->audio_in.blocksize,
// (double)(current_time - 1e6*priv->audio_secs_per_block*priv->audio_recv_blocks_total)/1e6);
// put the current skew into the ring buffer
priv->audio_skew_total -= priv->audio_skew_buffer[audio_skew_ptr];
priv->audio_skew_buffer[audio_skew_ptr] = current_time
- 1e6*priv->audio_secs_per_block*priv->audio_recv_blocks_total;
priv->audio_skew_total += priv->audio_skew_buffer[audio_skew_ptr];
pthread_mutex_lock(&priv->skew_mutex);
// linear interpolation - here we interpolate current skew value
// from the moving average, which we expect to be in the middle
// of the interval
// skew calculation
// compute the sliding average of the skews
if (priv->audio_recv_blocks_total > priv->aud_skew_cnt) {
priv->audio_skew = priv->audio_skew_total/priv->aud_skew_cnt;
// priv->audio_skew += (priv->audio_skew*priv->aud_skew_cnt)/(2*priv->audio_recv_blocks_total-priv->aud_skew_cnt);
} else {
// this smoothens the evolution of audio_skew at startup a bit
priv->audio_skew = ((priv->aud_skew_cnt+priv->audio_recv_blocks_total)*priv->audio_skew_total)/(priv->aud_skew_cnt*priv->audio_recv_blocks_total);
priv->audio_skew = priv->audio_skew_total/priv->audio_recv_blocks_total;
}
// put the current skew change (skew-prev_skew) into the ring buffer
priv->audio_skew_delta_total -= priv->audio_skew_delta_buffer[audio_skew_ptr];
priv->audio_skew_delta_buffer[audio_skew_ptr] = priv->audio_skew - prev_skew_uncorr;
priv->audio_skew_delta_total += priv->audio_skew_delta_buffer[audio_skew_ptr];
prev_skew_uncorr = priv->audio_skew;
prev_skew_uncorr = priv->audio_skew; // remember the _uncorrected_ average value
audio_skew_ptr = (audio_skew_ptr+1) % priv->aud_skew_cnt;
audio_skew_ptr = (audio_skew_ptr+1) % priv->aud_skew_cnt; // rotate the buffer pointer
// sliding average approximates the value in the middle of the interval
// so interpolate the skew value further to the current time
priv->audio_skew += priv->audio_skew_delta_total/2;
// now finally, priv->audio_skew contains fairly good approximation
// of the current value
// fprintf(stderr, "audio_skew = %lf, delta = %lf\n", (double)priv->audio_skew/1e6, (double)priv->audio_skew_delta_total/1e6);
// current skew factor (assuming linearity)
// used for further interpolation in video_grabber