[FFmpeg-trac] #4774(ffmpeg:new): Incompatibilities between XBMC/Kodi & mkvalidator relating to how FFmpeg muxes MKVs
FFmpeg
trac at avcodec.org
Sun Aug 16 16:11:55 CEST 2015
#4774: Incompatibilities between XBMC/Kodi & mkvalidator relating to how FFmpeg
muxes MKVs
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Reporter: Drag0nFly | Owner:
Type: defect | Status: new
Priority: normal | Component: ffmpeg
Version: git-master | Resolution:
Keywords: mkv muxer | Blocked By:
timecode chapter | Reproduced by developer: 0
Blocking: |
Analyzed by developer: 0 |
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Comment (by Drag0nFly):
Not sure if the questions are addressed to me, as I am not a developer,
but I'll attempt to answer as best I can.
I had the impression that the packet durations were embedded in the
pgssubs themselves, but this does not seem to be the case. In the most
recent clip I provided above, Mkvtoolnix removed the pgssubs entirely (not
just the tags), which caused the file to play back without issues. So that
was not a good example clip at all.
I have also tested these files with other players, including VLC/MPlayer,
etc. – in addition to comparing the behaviour with other software doing
x264/avc or x265/hevc re-encodes (such as Handbrake, which does not
exhibit this problem), as well as re-muxing affected files with MakeMKV
which corrects the issue (and produces no errors or warnings with
mkvalidator.)
This leads me to conclude that there is clearly something suboptimal in
the way FFmpeg muxes MKVs/generates these cue entries, as for the majority
of my library which has been processed through FFmpeg (again; due to its
excellent batch functionality and no-nonsense approach); mkvalidator
reports warnings with the cue entries and, more often than not, 'block at
nnn is not a keyframe' errors.
One can obviously argue that XBMC/Kodi is somwhat picky in not playing
these files correctly, but the bottom line is that this would not occur
had the FFmpeg muxer conformed to spec, like MakeMKV/Handbrake/MkvToolnix
all do.
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Ticket URL: <https://trac.ffmpeg.org/ticket/4774#comment:11>
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