[Ffmpeg-devel] Re: [PATCH] PKT_FLAG_B

[Michael Niedermayer]

Hi

On Tue, Aug 08, 2006 at 11:32:06PM +0200, Baptiste Coudurier wrote:
> Hi
> 
> Michael Niedermayer wrote:
> > [...]
> > 
> > knowledge of frame types of h.264 is not enough to calculate pts/ctts
> > so your B_TYPE flag wont help, for example:
> > 
> > [...]
> > 
> 
> OK for h264, there should be some way to figure that. For mpeg-4 in avi
> It get no pts/dts differences at all when stream contains B frames, even
> with -genpts.
> 
> >> Should demuxer set has_b_frame ?
> > 
> > if it has enough knowledge about the video then why not
> > 
> 
> Say my mpeg-2 comes from mov, parser won't be invoked and has_b_frames
> never set. Then gxf muxer won't ever set B frame :(
> Are you ok if I implement a very simple frame type detection in gxf
> muxer ? I think I need to detect closed gop also.

no objections


> 
> >> What about always invoking parser when stream copying ?
> > 
> > no
> 
> Ok, what's bad in it ?

costs cpu cycles and is often unneeded, maybe 
st->need_parsing = 2 could be done though by default for stream copying
it would just parse the headers but wont do any slow repacketization ...

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

In the past you could go to a library and read, borrow or copy any book
Today you'd get arrested for mere telling someone where the library is