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mpeg4: fix timestamp issues on too fast playback.

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Improve generation of presentation timestamps to be less sensitive
to input stream errors. In practise, GOP is also a synchronization
point for PTS calculation.

Signed-off-by: Gwenole Beauchesne <gwenole.beauchesne@intel.com>
This commit is contained in:
Wind Yuan 2012-04-26 04:00:41 -04:00 committed by Gwenole Beauchesne
parent 449606efc5
commit 1632b40982
1 changed files with 61 additions and 8 deletions
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69
gst-libs/gst/vaapi/gstvaapidecoder_mpeg4.c
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@ -73,6 +73,7 @@ struct _GstVaapiDecoderMpeg4Private {
GstClockTime seq_pts;
GstClockTime gop_pts;
GstClockTime pts_diff;
GstClockTime max_pts;
// anchor sync time base for any picture type,
// it is time base of backward reference frame
GstClockTime last_sync_time;
@ -314,8 +315,6 @@ decode_sequence(GstVaapiDecoderMpeg4 *decoder, const guint8 *buf, guint buf_size
priv->profile_changed = TRUE;
}
priv->seq_pts = gst_adapter_prev_timestamp(priv->adapter, NULL);
priv->calculate_pts_diff = TRUE;
priv->size_changed = TRUE;
return GST_VAAPI_DECODER_STATUS_SUCCESS;
@ -419,19 +418,64 @@ decode_gop(GstVaapiDecoderMpeg4 *decoder, const guint8 *buf, guint buf_size)
priv->closed_gop, priv->broken_link);
gop_time = gop.hours * 3600 + gop.minutes * 60 + gop.seconds;
priv->gop_pts = gop_time * GST_SECOND;
priv->last_sync_time = gop_time;
priv->sync_time = gop_time;
if (priv->calculate_pts_diff) {
priv->pts_diff = priv->seq_pts - priv->gop_pts;
priv->calculate_pts_diff = FALSE;
}
if (priv->gop_pts != GST_CLOCK_TIME_NONE)
priv->pts_diff += gop_time * GST_SECOND - priv->gop_pts;
priv->gop_pts = gop_time * GST_SECOND;
priv->calculate_pts_diff = TRUE;
priv->is_first_field = TRUE;
return GST_VAAPI_DECODER_STATUS_SUCCESS;
}
void
calculate_pts_diff(GstVaapiDecoderMpeg4 *decoder,
GstMpeg4VideoObjectLayer *vol_hdr,
GstMpeg4VideoObjectPlane *vop_hdr)
{
GstVaapiDecoderMpeg4Private * const priv = decoder->priv;
GstClockTime frame_timestamp;
frame_timestamp = gst_adapter_prev_timestamp(priv->adapter, NULL);
if (frame_timestamp && frame_timestamp != GST_CLOCK_TIME_NONE) {
/* Buffer with timestamp */
if (priv->max_pts != GST_CLOCK_TIME_NONE &&
frame_timestamp < priv->max_pts) {
frame_timestamp = priv->max_pts +
gst_util_uint64_scale((vol_hdr->fixed_vop_rate ?
vol_hdr->fixed_vop_time_increment : 1),
GST_SECOND,
vol_hdr->vop_time_increment_resolution);
}
} else {
/* Buffer without timestamp set */
if (priv->max_pts == GST_CLOCK_TIME_NONE) /* first buffer */
frame_timestamp = 0;
else {
GstClockTime tmp_pts;
tmp_pts = priv->pts_diff + priv->gop_pts +
vop_hdr->modulo_time_base * GST_SECOND +
gst_util_uint64_scale(vop_hdr->time_increment,
GST_SECOND,
vol_hdr->vop_time_increment_resolution);
if (tmp_pts > priv->max_pts)
frame_timestamp = tmp_pts;
else
frame_timestamp = priv->max_pts +
gst_util_uint64_scale((vol_hdr->fixed_vop_rate ?
vol_hdr->fixed_vop_time_increment : 1),
GST_SECOND,
vol_hdr->vop_time_increment_resolution);
}
}
priv->pts_diff = frame_timestamp -
(priv->gop_pts + vop_hdr->modulo_time_base * GST_SECOND +
gst_util_uint64_scale(vop_hdr->time_increment, GST_SECOND,
vol_hdr->vop_time_increment_resolution));
}
static GstVaapiDecoderStatus
decode_picture(GstVaapiDecoderMpeg4 *decoder, const guint8 *buf, guint buf_size)
@ -555,6 +599,12 @@ decode_picture(GstVaapiDecoderMpeg4 *decoder, const guint8 *buf, guint buf_size)
priv->prev_t_ref = priv->svh_hdr.temporal_reference;
}
else {
/* Update priv->pts_diff */
if (priv->calculate_pts_diff) {
calculate_pts_diff(decoder, vol_hdr, vop_hdr);
priv->calculate_pts_diff = FALSE;
}
/* Update presentation time, 6.3.5 */
if(vop_hdr->coding_type != GST_MPEG4_B_VOP) {
// increment basing on decoding order
@ -575,6 +625,8 @@ decode_picture(GstVaapiDecoderMpeg4 *decoder, const guint8 *buf, guint buf_size)
}
}
picture->pts = pts + priv->pts_diff;
if (priv->max_pts == GST_CLOCK_TIME_NONE || priv->max_pts < picture->pts)
priv->max_pts = picture->pts;
/* Update reference pictures */
/* XXX: consider priv->vol_hdr.low_delay, consider packed video frames for DivX/XviD */
@ -1058,6 +1110,7 @@ gst_vaapi_decoder_mpeg4_init(GstVaapiDecoderMpeg4 *decoder)
priv->sub_buffer = NULL;
priv->seq_pts = GST_CLOCK_TIME_NONE;
priv->gop_pts = GST_CLOCK_TIME_NONE;
priv->max_pts = GST_CLOCK_TIME_NONE;
priv->pts_diff = 0;
priv->calculate_pts_diff = TRUE;
priv->is_constructed = FALSE;