[MPlayer-users] Re: [MEncoder] Synchonization lost when using Vorbis in a OGM

[Moritz Bunkus]

Hi.

> It's a matter of the container format. ASF, QT, OGM, Matroska, and of
> course our own NUT support variable framerate just fine.

Not true for OGM, sadly. The FPS is stored in the header, and the
granulepos is - surprise, surprise - the frame number, and not the
timestamp of the video frame. This can be seen in ogminfo's output:

(ogminfo.c) v1:    7155 bytes granulepos:        220 pno:        222
start:       9134.12ms  end:       9175.83ms sync_ok  hdrlen: 0 

If the AVI contains a dropped frame then ogmmerge tries to mimic OggDS'
behaviour and sets the previous packet's length to the appropriate
number of frames. I don't have an example at the moment, but you can
exec 'ogminfo -v -v myfile.ogm | grep v1: | grep duration' to see these
packets.

-- 
 ==> Ciao, Mosu (Moritz Bunkus)
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