[MPlayer-users] Seek to frame for mencoder

[HR]

I can imagine there are many uses for this, so I'd really like to see
some ideas on implementing this. I've read previous posts regarding this
issue, where no response was given
(http://mplayerhq.hu/pipermail/mplayer-users/2003-June/033771.html).
demux_seek() ofcourse calls the approprate demuxer, the problem as
discussed elsewhere being that demux_seek_mpg() is "broken", at least
for DVD (VOB) input. I don't know about the other demuxers, but I assume
most of them might actually work. Thus, what we IMHO need ASAP is a
demux_frameseek_mpg().

I'm trying to read the mplayer source, trying to decide how to go about
such a task. Although some of my questions here might be silly to some
of you, and I have my suspicions for the answers beforehand, the answers
would enlighten me nonetheless.

Should/could a frame seek be done in the MPEG-PS video stream, assuming
that's the format in the unencrypted/decrypted DVD VOB?

Should/could the frame seek rather be done in a MPEG-ES? Demuxed from
MPEG-PS?

Skipping into a certain byteposition, relocating the nearest keyframe,
can one tell which sequence number this frame has?

Could a minimum of "fast forwarding" (ie "AV stream copy /dev/null") to
a certain frame number be quickly implemented as a temporary quick-fix?
Would be rather slow, but "something" is always a lot more than
"nothing"...

Is the reason why no one has done this for mplayer due to the task being
incredibly difficult, or that no one regards it as sufficiently
helpful/important/useful for it to be worth the effort?

HR