RepoMirrors/mpv
1
0
Fork 0
mirror of https://github.com/mpv-player/mpv synced 2025-03-20 02:09:52 +00:00
Code Issues Releases Wiki Activity

demux_mkv: don't set keyframe flag for timestamp-less audio frames

Browse Source 
Matroska has this weird concept of "lacing", which are really sub-blocks
packed into a larger actual block. They are demuxed as individual
packets, because that's what the decoder needs. Basically they're a
Matroska hack to reduce per-packet muxing overhead.

One problem is that these sub-blocks don't have timestamps. The
timestamps need to be created from the "default duration". If this
default duration isn't in the file header (or if we drop it when it has
a known broken value), the resulting packets won't have a timestamp.

This is an usual and weird situation, that may confuse the demuxer layer
(and backward playback in particular). Fix this by not setting the
keyframe flag for these.

This affects only audio packets. Subtitle lacing is explicitly not
supported (in theory would at least lack a way to specify durations),
and video won't usually use it for real video codecs (not every frame is
a "keyframe", timestamp reordering).
This commit is contained in:
wm4 2019-05-31 14:54:29 +02:00
parent af60a45fdf
commit ab19888ba4
1 changed files with 3 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
demux/demux_mkv.c
View File

@ -2693,14 +2693,15 @@ static int handle_block(demuxer_t *demuxer, struct block_info *block_info)
if (!dp)
break;
dp->keyframe = keyframe;
dp->pos = filepos;
/* If default_duration is 0, assume no pts value is known
* for packets after the first one (rather than all pts
* values being the same). Also, don't use it for extra
* packets resulting from parsing. */
if (i == 0 || track->default_duration)
if (i == 0 || track->default_duration) {
dp->pts = current_pts + i * track->default_duration;
dp->keyframe = keyframe;
}
if (stream->codec->avi_dts)
MPSWAP(double, dp->pts, dp->dts);
if (i == 0 && block_info->duration_known)