[MEncoder-users] two pass encoding with pullup

[D Richard Felker III]

On Wed, Apr 06, 2005 at 10:48:01PM +0200, Winterbird wrote:
> I feel I have to go back to the reason I posted this, because I didn't
> really get a clear answer. Is there anything in my options that could
> make mencoder fail to put the bits in the right place (causing ugly
> moving objects)? Or is it a bug? Or could it be that pullup drops
> different frames every pass and that way can't follow the log from the
> first pass?

Your "ugly moving objects": is there combing, or just mpeg artifacts?
If it looks fine after encoding with vqscale=2, then the problem is
just that your bitrate is too low or something. Actually a few
comments on your filter chain:

Do the cropping (and possibly scaling too?) before sharpening and
denoising.

Sharpening before encoding is a very bad idea. It will always reduce
quality. If you want a sharper picture do it at runtime during
playback.

Again, phase is not a good idea. If only a few combed frames are
making it through, try pp=l5 after pullup to blend them away and you
probably won't notice it..

Finally make sure you're using latest cvs. And you probably don't need
nearly so many fancy options to lavc. They slow you down a lot and
hardly improve quality.

Rich

> Encoding in three passes makes the encode only slightly better, I havn't
> tried more passes, and since encoding with all options activated goes
> very slow (0-1 fps) I probably wont have time to in quite some time.
> 
> sorry to bother you again...
> 
> Winterbird wrote:
> 
> > first pass:
> >
> >mencoder -noidx -nosound -noaspect dvd://1 -chapter 16-20 -ovc lavc -vf
> >pullup,softskip,phase,hqdn3d=12:0:10,unsharp=c7x7:0.5:l7x7:0.5,crop=704:464:6:8,scale=640:-3
> >-ofps 24000/1001 -lavcopts
> >qns=3:cmp=2:subcmp=6:preme=2:predia=3:dia=3:last_pred=3:vmax_b_frames=1:mv0:cbp:qprd:trell:preme=2:keyint=300:v4mv:mbd=2:vqscale=2:vpass=1
> >-o /dev/null
> >
> >second pass:
> >
> >mencoder -noidx -nosound -noaspect dvd://1 -chapter 16-20 -ovc lavc -vf
> >pullup,softskip,phase,hqdn3d=12:0:10,unsharp=c7x7:0.5:l7x7:0.5,crop=704:464:6:8,scale=640:-3
> >-ofps 24000/1001 -lavcopts
> >qns=3:cmp=2:subcmp=6:preme=2:predia=3:dia=3:last_pred=3:vmax_b_frames=1:mv0:cbp:qprd:trell:preme=2:keyint=300:v4mv:mbd=2:vbitrate=1145:vpass=2
> >-o finished.avi
> >
> >the difference is only that I added qns=3 on the second pass, and the
> >bitrate (vbitrate=1145 instead of vqscale=2).
> >  
> >
> 
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