[MPlayer-dev-eng] mencoder start position

[Jérôme Petazzoni]

> When I encode normal avi file then -ss option work correct (when I
> choose 51,27 then encoding start from that position) but I've got a few
> files in matroska and I want to cut them. To check start position in
> frames I must extract video track (mplayer doesn't show actual frame in
> matroska - only decoded frames). When I've got video track extracted
> from mkv mplayer and mencoder  as start position choose next keyframe
> from choosen position.

I seem to have the same problem with MPEG2 and MPEG4 streams. When I try 
to extract some specific frames (with "mplayer -ss", not "mencoder -ss" 
so I don't know if it's the same mechanism behind it ...) I observe some 
serious discrepancies between the frames extracted (I have the very same 
video sequence in VOB format, in MPEG4 ISO (quicktime) format, and a few 
others ; and when trying to get some specific frames, I end up with 
slights offsets - because indeed "mplayer -ss" doesn't do accurate seeking).

It seems that no mplayer guru wants this feature, so we will probably 
end up coding it ourselves :-)