[Ffmpeg-devel] [PATCH] increase max numbers of B frames

Michael Niedermayer michaelni
Tue Feb 21 22:28:07 CET 2006


On Tue, Feb 21, 2006 at 11:43:25AM +0100, Erik Slagter wrote:
> On Mon, 2006-02-20 at 12:58 -0800, Loren Merritt wrote:
> > > Interesting?! Would you care to elaborate a bit on this? The stats of
> > > x264 tell me that the b-frames (ok, on average) are a lot smaller than
> > > the I/P frames, what am I missing here? Maybe useful for the docs?
> > 
> > PPP.
> > PBPBP: the B-frames are much smaller than the P-frames, but the P-frames 
> [ ... ]
> Thank you, very interesting (saved the text for future reference). So
> basically you're saying that, using > 2 B frames, although the B frames
> are (still) smaller than the P frames, the P frames become that much
> larger that all gain is lost. I am going to test this :-)
> Anyway, weird that up 16 b frames are supported then, I really thought
> that was a major advantage of h264 over, say i.e. mpeg2.

no mpeg* or h26* spec has any limit on the number of b frames that i know of
you could put a billion b frames between P frames and it would be legal and
playable in most players



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