[MPlayer-users] To B or not to B

D Richard Felker III dalias at aerifal.cx
Tue May 11 04:33:03 CEST 2004


On Tue, May 11, 2004 at 12:26:02AM +0300, Ville Saari wrote:
> On Mon, May 10, 2004 at 01:03:06AM -0400, D Richard Felker III wrote:
> 
> > > Although, I still don't use B-frames myself, knowing that they aren't
> > > very well supported, esp. in hardware players.
> > 
> > They also have other major drawbacks like bad decoding performance.
> 
> If the machine is able to play DVD's then mpeg4 should be no problem
> whatsoever, B-frames or not. It's so much lighter to decode (or
> mplayer's decoder is so much better optimized).

Huh? Decoding 720x480 mpeg4 takes a good bit more cpu time than
720x480 mpeg2, at least if you use lots of mpeg4 features...

> Encoding has some delay, but that's an issue only if you do live streaming.

Out-of-order decoding also has a big impact on cache performance, and
hurts performance of temporal filtering greatly because you can't
perform filtering in the decode order.

> The only annoyance for me is that I can't use pp=hb/vb on B-framed video,
> because it filters B-frames too hard causing flicker.

This is annoying but easy to fix. Just preprocess the quantizer table
before passing it to vf_pp.

Rich




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