[MPlayer-users] Q: libavcodec, B-frames, mbd, v4mv

[Tuukka Toivonen]

On Mon, 25 Aug 2003 mslama at email.cz wrote:

>besides CVS log? B-frames are disabled by default. Any notes/suggestion
>about enabling them? (ie. what is probable gain of using them?)

Very little. I was recommended to use a single B-frame at maximum. Anyway
the difference is so small that I wonder whether it's a libavcodec-specific
problem or why the standards include B-frames anyway?

You might want to search for the encoding script I posted here a while ago.
The important thing is to use vhq, two or three passes, and trell, those
have biggest affect to the quality. The rest do not have much effect, but
you could use:

precmp=6:cmp=6:subcmp=6:
- Should use rate-distortion optimization, but I'm not sure... helps
  slightly, at least usually.
predia=6:dia=6:
- Larger search area I suppose.
vlelim=-3:vcelim=5
- Has been frequently suggested, although I'm not sure if it has actually
any practical change to the quality.