[Ffmpeg-devel] [PATCH] increase max numbers of B frames (original) (raw)

skal skal
Tue Feb 21 13:44:39 CET 2006 

Hi Loren and all,

On Mon, 2006-02-20 at 12:58 -0800, Loren Merritt wrote: [...]

PBBBPBBBP: again, each frame is bigger than it would be in 2 consecutive, and now there's a decent chance that 67%->75% B-frames isn't enough to pay off. Though it's a bit more useful than in mpeg4, due to B-pyramid (which I won't detail here) and miscellaneous other improvements in the codec.

Maybe this point is worth some details: h264 permits use the middle B-slice as reference, making the reference anchors not so far from the remaining inbetween b-slices (non-refs). So, you're back to deciding PbBbP over PbPbP for the refs, which is quite similar to the PBP vs. PPP decision, as far as refs placement is concerned. Well, this is quite an uncharted (and slippery) land, but some are advocating use of GOPs as big as 32 (!): http://ftp3.itu.int/av-arch/jvt-site/2005_07_Poznan/JVT-P014.zip

bye!

Skal

(ps: any other references on this topic is most welcome)

More information about the ffmpeg-devel mailing list