strange "mismatch" error

[Blue_MiSfit]

Have a look at this screenshot of a high motion scene
http://people.ucsc.edu/~dpresteg/bug1.jpg

You are seeing a person's (mostly) forehead - notice the strange line that looks almost like it's interlaced or like a vsync related "tearing" artifact that you see in games when you disable vsync.

SO irritating when you're seeing lots of high motion! Regardless I checked the source and found it to be clean. I was encoding a DVD at 800x576 at 1702kbit or so using XviD 1.0 RC3 with the following settings:

VHQ=4
GMC
QPEL
Adaptive Quant
Chroma Motion
Chroma Optimize
Trellis
B-Frames @ (5, 1.5, 1.0)
hvs-best matrix
Turbo

My AVS was a standard lanczos resize and undot - with version 2.5.4
Also VDubMod 1.5.10.1 was used. I know it's a bit unstable, but both passes happily completed.

This screenshot was taken in virtual dub, so it's not player related. Both ffdshow and the XviD RC3 decoder produce the same error. So I'm thinking it definatley is an encoding error.

Any ideas as to what the problem could be?

Thanks in advance
~misfit

[Koepi]

Looks to me like an over-quantization-artefact. Since the area of the picture is "middle between dark and bright", adaptive quantization kicked in and quantized it more than the rest of the image which produces this artefact.

If you think about it, it did what it was supposed to. But since you're watching your movies in ultra-slow-motion ;) you shouldn't use adaptive quantization anymore. The effect shouldn't be so badly visible when stepping back a little from your monitor and watching the movie "in the full run".

Regards
Koepi

[Blue_MiSfit]

I see... so to avoid this in the future I should either step back or run tv out thus ignoring it ... or re-encode without adaptive quant?

~misfit

[zulu]

I've been using XviD for quite a while and i never encountered those red arrow artefacts.

[Koepi]

LOL :)