[FFmpeg-devel] [PATCH] ffmpeg: ignore forward gaps for subtitles streams

[Nicolas George]

ffmpeg: ignore forward gaps for subtitles streams

In formats that have timestamps discontinuities (like MPEG-PS), ffmpeg (the
command-line tool) detects gaps of more than 10ms (configurable) between a
packet's timestamps and the expected timestamp as a discontinuity and adjust
an offset for future adjustment.

For subtitles streams, forward gaps of several seconds, er even dozens of
minutes, are perfectly normal, but trigger this countermeasure. Thus:

./ffmpeg_g -v 10 -analyzeduration 10000000 -probesize 100000000 -copyinkf \
  -i some.vob -ac 2 -scodec dvdsub -f dvd -y /tmp/out.vob

will first print something like that:

timestamp discontinuity 28000000, new offset= -197672677.52

and shortly after fail with:

[dvd @ 0xbdbfa0] Application provided invalid, non monotonically increasing
dts to muxer in stream 2: 676800 >= 676800

The attached patch fixes that by ignoring positive gaps in subtitles
streams.

Regards,

-- 
  Nicolas George
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