[MPlayer-dev-eng] [PATCH] mencoder, B-frames, and video/audio delay

Rich Felker dalias at aerifal.cx
Sat Jan 21 01:25:43 CET 2006


On Fri, Jan 20, 2006 at 04:09:15PM -0800, Corey Hickey wrote:
> The attached patch disables the portion of mencoder.c that decides
> whether to adjust the A-V sync based upon the relative positions of the
> muxer stream timers. I don't know if that's the correct fix. If mencoder

This is definitely not correct, and will make a/v sync (and choice of
which frames to keep and how many) totally wrong for any encoding
where there's not an exact one-to-one correspondence of input frames
to output frames. If you want this behavior, just use -noskip.

Instead you need to make the encoder advertise the number of frames of
encoding-delay it has, and fake the muxer timer to compensate for it.

BTW I think there's a corresponding problem at the _decoder_ end too,
which you should check out. (Use h264 with deep pyramid to test it..)

> is adjusted quickly), with 16 B-frames and perfect a-v sync. If somebody
> more knowledgeable than I gives me the go-ahead, then I will commit this
> patch.

Don't take this as a flame, buf if you commit this it might break the
1000000000000l cola record. :)

Rich




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