[MEncoder-users] MEncoder Creating "Snip-Its" of Audio, Video, and Subtitle files

Christopher Hunt chunt102783 at gmail.com
Wed Jun 12 18:04:03 CEST 2013


>Are you sure it still is? There are possibly issues in corner-cases,
>but I think that -of lavf should actually be working (though just making
>all steps together work in FFmpeg would be the better solution).

** MUXER_LAVF
*****************************************************************
   REMEMBER: MEncoder's libavformat muxing is presently broken and can
generate
   INCORRECT files in the presence of B-frames. Moreover, due to bugs
MPlayer
   will play these INCORRECT files as if nothing were wrong!
**************************************************************************************

This message still exists in the muxer_lavf.c code as of a February svn
check out of MPlayer and the file produced by using the -of lavf flag is
not playable in QuickTime however it is (as the message suggests) playable
in MPlayer, but with the limited testing that I did with that option the
output files were not even playable in VLC.

I would do all the steps in ffmpeg if I hadn't spent development time in
MPlayer adding further subtitle formats to subreader.c, had I noticed that
passing a sub file with -subfile (rather than -sub) directed the decoding
to the chosen demuxer (in my case ffmpeg) I would have added those formats
to ffmpeg and been able to "burn in" those subs at that level and not need
to use MEncoder however as hindsight is 20-20 and duplicating the code into
ffmpeg is unadvisable at this moment I'm looking to see if it's feasible to
do this through MEncoder.

>I am not really sure that seeking in the audio file together with copy
>will result in a valid file.

In my test cases the audio files only contained lpcm data so the issue of
decoding the audio from a valid starting point was not a concern but I
agree that in compressed audio that would be a concern (or have I missed
something).


-- 
Respectfully,


Chris


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