[MEncoder-users] new doom9 codec comparission

Rich Felker dalias at aerifal.cx
Wed Dec 7 22:41:21 CET 2005

On Wed, Dec 07, 2005 at 12:22:37AM -0800, Corey Hickey wrote:
> Here is my semi-final mpeg-4 encoding line for Doom9.
> for i in 1:turbo 2 ; do
>   mencoder matrix.vob -aid 128 -oac copy \
> -vf crop=718:356:0:60,scale=640:272 -sws 9 -ovc lavc \
> -lavcopts vcodec=mpeg4:vbitrate=581:mbd=2:mv0:trell:cbp:\
> precmp=2:cmp=2:subcmp=2:predia=2:dia=2:preme=2:v4mv:\
> last_pred=2:vqcomp=0.6:vmax_b_frames=2:vpass=$i \
> -ofps 24000/1001
> done
> After a couple dozen full encoding tests and numerous partial ones, the
> best result I have is little different from the "Very high quality"
> suggestion in the mplayer docs. Differences are:
> ----docs --------mine---------------reason-----------
> last_pred=3    last_pred=2   slower, no difference
> vb_strategy=1  <default>     lower PSNR, worse quality
> qns=2          <default>     too slow for this test

qns may be slow, but it's the best perceptual-quality improvement that
doesn't show up in psnr results. you really should test and see,
because it might make all the difference!

> Unfortunately, the quality drop from using threads=2 is, in my opinion,
> unacceptable.

Definitely. I'm against using threads.

> Coming up: snow
> I've been queuing up snow tests to run in the early morning after that
> night's mpeg-4 encodes finish. I have a few more that will run tonight.
> The snow command will be like the one above, except with these differences:
> for i in 1:vqscale=2.15 2:vbitrate=581 ; do
>   ...same options as above...
>   -lavcopts vcodec=snow:vstrict=-2:cmp=1:subcmp=1:mbcmp=1:qpel:vpass=$i
> done
> Some time tonight my computer will test the effect of threads=2 with and
> without last_pred=2.

I don't think snow supports threads.


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