[MPlayer-dev-eng] [PATCH] new mpeg muxer

Zoltan Hidvegi mplayer at hzoli.2y.net
Thu Feb 24 08:09:05 CET 2005


D Richard Felker III wrote:
> the "correct" way, as far as i'm concerned, is to encode at 24fps, but
> then modify the output stream to indicate 30fps and to add tff/repeat
> flags to alternating frames so as to emulate 24fps inside a 30fps
> stream, aka "soft telecine". i'm not sure whether this nasty hackery
> belongs in the encoder or in the muxer, though...

Actually, I wish there was a way where a filter can set the rff/tff
flags which could get passed down to the encoder and muxer.  That
would allow filterss like pullup or filmdint to output at any fps
between 20000/1001 and 30000/1001.  And the reason you need that is
that many things on TV are rate-changed.  Even for TV shows, the
original is shown at 24000/1001 fps, but the repeat is sped up to make
room for an extra 30sec commercial block.  The the framerate changer
they use sucks badly, as it just blindly drops fields from the
telecined content, so you get 2-3-2-2-2-3-2 or 3-2-3-1-3-2-3 telecine,
but never 2-3-2-2-3-2 which would be the smoothest.

Alternatively, mencoder could set the fields automatically.  Currently
mencoder skip/dup frames to keep the A-V sync, but it could use the
rff flag instead.  It could automatically add or omit rff to keep the
A/V sync, and the advantage is that it has a half-frame precision.  In
that case the video filters could produce any frame rate up to
30000/1001, and pullup or filmdint would just work without specifying
-ofps or using -ofps 30000/1001.

Btw, is there a way to use vcodec=mpeg4 with -of mpeg?  That's not
for DVD, just for computer playback, but using mpg instead of avi?
I've tried it, but it did not work for me, but maybe I just do not
know what I'm doing.

Zoli




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