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demux_lavf: try harder to make up a frame rate

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Frame rate information is mostly irrelevant for playback, but it's
needed at least to convert frame numbers used in some subtitle formats
(like MicroDVD) into timestamps. Libavformat stopped making up a frame
rate if no "reliable" information is available (commit 7929e22bd
"lavf: don't guess r_frame_rate from either stream or codec timebase",
1.5 months ago). This caused a regression with AVI files and MicroDVD
subtitles. Add a heuristic similar to what libavformat used to have,
to make up FPS values which should work at least for the AVI+MicroDVD
use case.
This commit is contained in:
Uoti Urpala 2012-04-14 02:43:40 +03:00
parent 74ad0b4284
commit 4680beb6dc
1 changed files with 16 additions and 2 deletions
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18
libmpdemux/demux_lavf.c
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@ -417,8 +417,22 @@ static void handle_stream(demuxer_t *demuxer, AVFormatContext *avfc, int i)
sh_video->video.dwRate = codec->time_base.den;
sh_video->video.dwScale = codec->time_base.num;
}
sh_video->fps = av_q2d(st->r_frame_rate);
sh_video->frametime = 1 / av_q2d(st->r_frame_rate);
/* Try to make up some frame rate value, even if it's not reliable.
* FPS information is needed to support subtitle formats which base
* timing on frame numbers.
* Libavformat seems to report no "reliable" FPS value for AVI files,
* while they are typically constant enough FPS that the value this
* heuristic makes up works with subtitles in practice.
*/
double fps;
if (st->r_frame_rate.num)
fps = av_q2d(st->r_frame_rate);
else
fps = 1.0 / FFMAX(av_q2d(st->time_base),
av_q2d(st->codec->time_base) *
st->codec->ticks_per_frame);
sh_video->fps = fps;
sh_video->frametime = 1 / fps;
sh_video->format = bih->biCompression;
if (st->sample_aspect_ratio.num)
sh_video->aspect = codec->width * st->sample_aspect_ratio.num