[FFmpeg-devel] Question about PAFF decoding

Michael Niedermayer michaelni
Thu May 31 20:10:43 CEST 2007


On Thu, May 31, 2007 at 08:04:39PM +0200, Michael Niedermayer wrote:
> > @Loren: if you want to give him mine i'd be happy: tjordan at macrosystem.de
> > 
> > Here we go:
> > 
> > with PAFF material a frame seems to be coded in two seperate fields,
> > each with his own NAL start code (00 00 00 01 09 xx). I have seen two
> > consecutive fields of one frame, first with xx=10, second xx=30, so
> > first field has only I slices, the second P-slices. Other streams have
> > 2x the 10 code. Bizarre...
> > 
> > Would PAFF decoding work like decoding two consecutive frames with half
> > height?
> no

to elaborate here, decoding fields is similar to decoding 2 frames with half
height but its not identical you have to add plenty of field specific code
when i originally started implementing the h.264 decoder i tried to support
paff/mbaff too, but quickly gave up as there where too many mbaff/paff
specific cases to think about / deal with ...


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Concerning the gods, I have no means of knowing whether they exist or not
or of what sort they may be, because of the obscurity of the subject, and
the brevity of human life -- Protagoras
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