Maybe a DivX 5.0.2 decoder bug?

[domingol]

The film that gives me this curious playback problem is 'La Pianiste' (french movie, i think). It was encoded with DivX 5.0.2 (two passes), 624x336 Soft bicubic Resize (GKnot), with GMC & B-frames, and no other parameters enabled. At the begining of the movie, decoding with DivX 5.0.2 (no mather wath of the new "improving playback" options were enabled, even with all those options disabled), i get these strange artifacts (see attached file). The frame was captured with BSPlayer's option (as it seems to be a decoder problem, and Vdub uses the DivX 5.0.2 decoder too, i need to catch frames with BSPalyer, in order to compare with ffdshow), so the frames are not the same, but there's no need for that ;)
With ffdshow filter enabled (DivX 5.0.1 support version; the last), the playback is perfect and the artifacts aren't present. I'll attach ffdshow capture as a reply.

P.S. Sorry for my poor english (seems that it has strange artifacts too :D )

[domingol]

ffdshow capture.

P.S. I've attached the 2 files in the faq's way, so i think we have to wait til Acaila say OK ;)

[Acaila]

Next time please cut off the portions of the picture that are not relevant :)

As for your bug, I've never seen anything like it, so I have no idea why it happens.

[domingol]

Thx, next time i'll do it :)

[domingol]

Replying to myself, there's another guy with the same problem at divx.com forum.

http://forums.divx.com/viewtopic.php?forum=13&topic=35211

Seems that a combination of GMC + low bitrates drive us to the same problem. Anyway, it happens only with DivX 5.0.2 decoder.

[Vosper]

I have a similar problem with an encode of Highlander. It's only right at the start. The artifacts appear, dance around for a bit and then disappear when the company logo moves across them. After that, it's all good. This video was also encoded with GMC, but at a reasonable bitrate > 1200 if I remember. I have normal psyvis, b-frames but no Q-Pel.

Craig

PS I attached an image, was unsure how to embed it in the post. Sorry.

[domingol]

Yes, it's the same problem. I've seen this effect no matter what bitrate was used (my fault). It only appears if GMC is enabled.

[freezer]

I did some encodings of Futurama episodes from DVD, overall quality is really great (640x480, 900 kBit/s => 160MB, DivX 5.02 Pro, GMC, bidir, psyvis normal). But here and there are some of this pieces of artifacts - mainly in the end credits where it is really worse. I have attached a sample where you can see the problem. I first thought it shows part of the keyframe, but it is from the credits 10 frames after the keyframe.
#
0 keyframe
10 frame which parts appear as artifacts
33 first appearance of artifacts
35 no artifacts
37 artifacts
39 no artifacts
...
and so on: alternating 2 frames artifacts, 2 frames no artifacts, until the next keyframe comes.
I think I will use a lower keyframe value to fight this problem or abandon the use of GMC until this is fixed.

[Acaila]

I think something went wrong with your attachment, because I don't see anything...

[freezer]

Somehow the attachment didn't attach %-)
Hope this one works (it's only 13kB).