[MEncoder-users] Can't get enough quality with xvid

[Pepe]

El Domingo, 24 de Septiembre de 2006 19:07, Vladimir Mosgalin escribió:
> Hi Pepe!
>
>  On 2006.09.24 at 18:48:43 +0200, Pepe wrote next:
> > I re-encoded to scale to 704x576, but image in my video is worse, more
> > "blocky". This is the command I used (this is the 2nd pass, the first one
> > is the same with "pass=1:turbo"):
> >
> > mencoder -noodml -o my_video.avi \
> >   -oac copy \
> >   -ovc xvid \
> >   -xvidencopts
> > bitrate=1064:nointerlacing:nopacked:pass=2:max_iquant=31:max_pquant=31:ma
> >x_bquant=31:max_bframes=0 \
> >   -vf-add scale=704:576 -zoom \
> >   -vf-add harddup \
> >   -force-avi-aspect 4:3 \
> >   -sws 9  \
> >   orig_video.avi
> >
> > I didn't use b-frames because my dvd player doesn't like them in hi-res
> > videos.
>
> That's a shame. b-frames in xvid improve quality a lot.
>
> > Is there any other option I should use to improve quality?
>
> try
> me_quality=6:quant_type=mpeg:keyframe_boost=15:trellis:chroma_me:chroma_opt
>:hq_ac:vhq=1

Just to be sure. The values for me_quality, quant_type, trellis, chroma_me, 
hq_ac and vhq are already the default values that mencoder would use, so I 
don't need to explicitly use them, do I?

> and use higher bitrate. If you reencode together with increasing
> resolution and disabling b-frames, it's quite possible that you won't be
> able to avoid blockness unless you increase your bitrate. Try 1500,
> 2000, 2500...

Yesterday I encoded the video again, but this time using a lower resolution 
(576x432), and quality improved.

Anyway I've just re-encoded the video using your options, and I also enabled 
b-frames, using the same bitrate and the same resolution (704x576) as before. 
Now definitely image quality is best than before, although some blocks can 
still be seen. Unfortunately when watching it in my dvd player the image 
blinks sometimes a little bit in the lower part of the screen. That happens 
when I use b-frames in videos with high resolution. I don't know why it is.

-- 
Pepe