[MPlayer-users] MPlayer-1.0pre4 bug with divx4 multipass filter

[D Richard Felker III]

On Sun, Sep 12, 2004 at 10:51:54PM +0400, Vladimir Mosgalin wrote:
> On Sun, 12 Sep 2004, D Richard Felker III wrote:
> 
> DRFI>> Hmm.. Imho pp filter isn't slow. It's faster than mpeg4 decoding in
> DRFI>> twisted cases, like: xvid + qpel decoded by xvid (it can't be decoded by
> DRFI>> lavc),
> DRFI>
> DRFI>huh? lavc decodes any xvid file you throw at it. are you sure
> DRFI>you're not using an _ancient_ libavcodec that's not getting updated
> DRFI>when you cvs update? that would explain all your problems with
> DRFI>lavc.....
> 
> Right now, I'm using dev-RPM-CVS-040904-03:12-3.3.2. Lavc was cvs up'ed
> the same day, of course.

are you using redhat? probably they have some broken compiler/kernel
or lib that's messing up lavc. you seem to be having lots of problems
that no one else can see...

> When trying to decode xvid-encoded content with lavc, there are random
> distorted blocks appearing all over the image if qpel was used. If
> "packed" xvid option was used, the situation is even worse. Personally,
> I don't like qpel, so I don't suffer from this problem, but some fansub
> groups encode with xvid and use qpel, so setting xvid as default decoder
> is a good idea.

huh? i watch plenty xvid-encoded fansubs and other files, so i'm sure
some of them must be using qpel... i've never seen such a bug.

> There are another problems when decoding with lavc. When running
> "mplayer xvid-encoded-file.avi -vf noise=12uah", mplayer writes
> "vf.c: have to REALLOCATE buffer memory :(" several times a second,
> and often, but not always (in about 50% cases) segfaults on exit (in
> uninit_vcodec), and then hangs. Interrupting doesn't help, only sigkill
> does. Also, several upper lines get distorted.

this has nothing to do with xvid/lavc...and in fact it should never
happen. if you see a crazy bug like this, please upload samples and
make a bug report! obviously no one else has experienced this problem,
or at least none of the developers.

> DRFI>> which eats about 50% of my athlon 3200+ cpu on dvd resolution.
> DRFI>
> DRFI>pp filter doesn't work, in my experience. it still has blocks. you
> 
> It does. pp=ac, at least. I wonder why it isn't in pphelp page?

no idea...it should be. you're right, it does work a _lot_ better than
the old deblock filters. but spp is still much better for really
crappy files.

> DRFI>2) in near-solid-black areas, where adjacent blocks only had the dc
> DRFI>coefficient (solid color) and even 1 level difference between them was
> DRFI>made visible by the insane gamma correction.
> 
> AFAIR, this is not the case either. Even if it effects a bit, it doesn't
> explain why xvid performs much better (whis is the point of this
> discussion).

i expect you'd see these with xvid too... i guess you don't have your
gamma set all the way up to 5.0 like i tested... ;)

rich