Archived from groups: rec.video.desktop (
More info?)
"Jan Panteltje" <pNaonStpealmtje@yahoo.com> wrote in message
news:1110151507.dfae2bb34b9deb7e04cdcd39119036a3@teranews...
> On a sunny day (Sun, 06 Mar 2005 14:13:01 GMT) it happened Jan Panteltje
> <pNaonStpealmtje@yahoo.com> wrote in
> <1110118389.396110bc77f87ee4d879eb96d09bd6c2@teranews>:
>
>>The thing is, I KNOW what to look for in mpeg2 as artefacts...
>>here I see some specific things new for me (caused by the wavelet
>>encoding?).
>>I will have to run some tests on 100% accurate material, some old AVI
>>clips
>>I made with Blender, the same I used to test the VP6 codec (in HD).
>>Need a much faster PC...
> I did a snasty test:
> I downloaded part of the blender tutorial... kfipo.avi
>
http://www.ibiblio.org/bvidtute/
> -rw------- 1 root root 66124414 Mar 6 16:03 kfipo.avi
>
> and compressed it with:
> nice -n 19 \
> mencoder \
> kfipo.avi \
> -nosound \
> -o out5.avi \
> -ovc lavc \
> -lavcopts
> vcodec=snow:vstrict=-1:vqscale=3:qpel:cmp=1:subcmp=1:mbcmp=1
![:p :p]()
red=0
>
> that results in:
> -rw-r--r-- 1 root root 39492554 Mar 6 18:35 out5.avi
> not even a factor 2, and it looks really bad on some of the the graphics,
> (look at those lines on the canvas, form 45 minutes onwards).
> So much for that....
>
> But is was a NASTY test :-)
> (and I also tried with pred=1, a little betetr, but not much).
> So it seems 'wavelet' - at least this snow codec - does not compress SOME
> images well.
> Especially in these graphics, where actually only the cursor moves (much
> of
> the time), one would expect a very high compression (almost to zero
> theoretically), but I get only 50% with bad artefacts.
> Maybe 2 systems could be combined, use DCT for some frames, and wavelet
> for other... and a flag in each frame sequence GOP to indicate how the
> decoder
> should handle it.
> Maybe this would be too 'visible'.
> For sure there is a lot that can still be done to improve compression of
> images, we should not drop the 'good' of the old system...
> Mpeg2 IS really good.
> Anyways, I learned some more about wavelet codecs, give it a try :-).
> Nothing like hands on experience.
I'm still licking my wounds from trying the AVC/H264 codec's
that have become available, and it was so promising in the
beginning. What does "Gspot" say about your kfipo.avi test file?
There might be something odd throwing it off.
Luck;
Ken