[XviD-users] B-Frames & Trellis, and more...

[Picasso Pablo]

Hello,

I am just a simple user who experimented with XviD a year back, so these 
are only my thoughts:

Lee Morgan wrote:
> 1) I read that only 2 b-frames are recommended, I suppose this is 
> because of high motion scenes - due to XviD not having adaptive B-frames?

AFAIK it's because of hardware and software compatibility. Some older 
filters / decoders for H.263 MPEG4 supported only 2 consecutive 
b-frames, but nowadays, if you are using these videos with a software 
XviD (ffdshow, ...) decoder, you don't have to worry about.

> 
> 2) If I'm using vhq=4 should / do I gain anything from also using trellis?
> 

Dunno :(

> 3) Would using lumi_mask help any?
> 

Well, using lumi masking means giving one step worse quantisation (in 
your case quant=3) to (macro)blocks being dark, when there is enough 
light in other parts of the picture (thus gaining attention). I would 
recommend it, since it decreases size and retains psychovisual quality.

> 4) How about altering bf_threshold?
> 

Is it the same as BVOP sensitivity? If yes, I would do that. But it 
depends on the quality and attributes of the video (e.g. HQ movie with 
sharp edges and "movie grain" filters used - maybe 0-5; for a Pixar 
animation - maybe 15-20.)

Good Luck!

-- 
    Picasso Pablo    (http://picasso.atrip.sk, ICQ: 174412909)