[MPlayer-users] Re: encoding quality - bpp, resolution, quants and quality

[Matthias Wieser]

Am Dienstag, 9. September 2003 15:33 schrieb Tuukka Toivonen:

> Just a comment: I've recently experimented encoding PAL video (768x576

Video or TV? TV normally has more noise. Denoise3d should help.

> at 25 fps scaled down to 352x288, 640x480, or not at all) and with 1.2
> Mbit/s (0.109-0.156) it was totally unacceptable quality to me (except
> when scaling down to 352x288, but that's somewhat low resolution). So
> now I'm scaling to 640x480 and coding at 2 Mbit/s (0.26 bpp). Even with
> this bitrate 640x480 appears to be better than unscaled size.

Those bpp values are probably thought for two-pass encoding. If you only 
use "vhq" then you need more bpp than if you use 
"vhq:precmp=2:cmp=2:subcmp=2:trell".

> Is there a reason you are using Xvid instead of ffmpeg's MPEG-4 coder? 
> I thought the latter would be better, or is there significant
> difference anyway?

The latter _was_ better. Ther are no recent comparisons between both but  
Xvid is better than many other modern codecs, so Xvid has probably become 
better than libavc.

> Have you experimented whether -sws 2 or 9 is better (or something
> else?). I'm using 9, I suppose it should be better in theory?

Do you mean, 9 should be sharper? If so, then that may be bad because more 
bit/s are needed.

If sws 2 is faster I would choose that and 
vcodec=[...]vhq:precmp=2:cmp=2:subcmp=2 which produces better files than 
only vhq or vhq:v4mv.

              Matthias