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demux_mkv: attempt to fix rounded timestamps

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There is some potential for breakage. If it happens, this might have to
be disabled by default.
This commit is contained in:
wm4 2015-04-23 19:35:15 +02:00
parent e9ca0b1522
commit 90d7e51643
2 changed files with 30 additions and 1 deletions
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12
DOCS/man/options.rst
View File

@ -2112,6 +2112,18 @@ Demuxer
will be slower (especially when playing over http), or that behavior with will be slower (especially when playing over http), or that behavior with
broken files is much worse. So don't use this option. broken files is much worse. So don't use this option.
``--demuxer-mkv-fix-timestamps=<yes|no>``
Fix rounded Matroska timestamps (enabled by default). Matroska usually
stores timestamps rounded to milliseconds. This means timestamps jitter
by some amount around the intended timestamp. mpv can correct the timestamps
based on the framerate value stored in the file: if the timestamps does
not deviate more than 1 frame (as implied by the framerate), the timestamp
is rounded to the next frame, which should undo the rounding the muxer
did.
This can break playback if the framerate value stored in the file is too
high.
``--demuxer-rawaudio-channels=<value>`` ``--demuxer-rawaudio-channels=<value>``
Number of channels (or channel layout) if ``--demuxer=rawaudio`` is used Number of channels (or channel layout) if ``--demuxer=rawaudio`` is used
(default: stereo). (default: stereo).

19
demux/demux_mkv.c
View File

@ -24,6 +24,7 @@
#include <stdio.h> #include <stdio.h>
#include <inttypes.h> #include <inttypes.h>
#include <stdbool.h> #include <stdbool.h>
#include <math.h>
#include <assert.h> #include <assert.h>
#include <libavutil/common.h> #include <libavutil/common.h>
@ -190,6 +191,7 @@ struct demux_mkv_opts {
int subtitle_preroll; int subtitle_preroll;
double subtitle_preroll_secs; double subtitle_preroll_secs;
int probe_duration; int probe_duration;
int fix_timestamps;
}; };
const struct m_sub_options demux_mkv_conf = { const struct m_sub_options demux_mkv_conf = {
@ -198,11 +200,13 @@ const struct m_sub_options demux_mkv_conf = {
OPT_DOUBLE("subtitle-preroll-secs", subtitle_preroll_secs, OPT_DOUBLE("subtitle-preroll-secs", subtitle_preroll_secs,
M_OPT_MIN, .min = 0), M_OPT_MIN, .min = 0),
OPT_FLAG("probe-video-duration", probe_duration, 0), OPT_FLAG("probe-video-duration", probe_duration, 0),
OPT_FLAG("fix-timestamps", fix_timestamps, 0),
{0} {0}
}, },
.size = sizeof(struct demux_mkv_opts), .size = sizeof(struct demux_mkv_opts),
.defaults = &(const struct demux_mkv_opts){ .defaults = &(const struct demux_mkv_opts){
.subtitle_preroll_secs = 1.0, .subtitle_preroll_secs = 1.0,
.fix_timestamps = 1,
}, },
}; };
@ -2327,6 +2331,19 @@ exit:
return res; return res;
} }
static double fix_timestamp(demuxer_t *demuxer, mkv_track_t *track, double ts)
{
mkv_demuxer_t *mkv_d = demuxer->priv;
if (demuxer->opts->demux_mkv->fix_timestamps && track->default_duration > 0) {
// Assume that timestamps have been rounded to the timecode scale.
double quant = mkv_d->tc_scale / 1e9;
double rts = rint(ts / track->default_duration) * track->default_duration;
if (fabs(rts - ts) < quant)
ts = rts;
}
return ts;
}
static int handle_block(demuxer_t *demuxer, struct block_info *block_info) static int handle_block(demuxer_t *demuxer, struct block_info *block_info)
{ {
mkv_demuxer_t *mkv_d = (mkv_demuxer_t *) demuxer->priv; mkv_demuxer_t *mkv_d = (mkv_demuxer_t *) demuxer->priv;
@ -2349,7 +2366,7 @@ static int handle_block(demuxer_t *demuxer, struct block_info *block_info)
return 0; return 0;
} }
current_pts = tc / 1e9 - track->codec_delay; current_pts = fix_timestamp(demuxer, track, tc / 1e9) - track->codec_delay;
if (track->type == MATROSKA_TRACK_AUDIO) { if (track->type == MATROSKA_TRACK_AUDIO) {
if (mkv_d->a_skip_to_keyframe) if (mkv_d->a_skip_to_keyframe)