[MPlayer-users] DivX/XviD qpel decoding

[Ivan Kalvachev]

Unfortunalty the green smearing bug is not lavc one, but in both divx4/5
and xvid bug. It comes from the incaccurte DCT that they are using. That
DCT comes from libmpeg2, and is not good enough for mpeg4 standart, but is
used becouse of its good speed.
To workaround it use the same idct in lavc with this option:
mplayer -lavdopt idct=4

Best Regards
   Ivan Kalvachev
  iive

Jakub Misak said:
> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
>>> I noticed that MPlayer with libavcodec can't properly decode video
>>> encoded
>>> with DivX 5.1 (possibly XviD, too) and Qpel. There are some slightly
>>> distorted "waves" in some parts of the picture, which disappear with
>>> the
>>> next keyframe. It's quite subtle and noticeable only in some particular
>>> places, but the artifacts are not there with the DivX 5.0.5 decoder.
>>maybe u could tell us exactly where these places are?
>
> OK, I tried to explain it in the .txt file, but now I also uploaded a png
> screenshot with the area marked in green coulour - it shows frame no. 239,
> the highlighted area gets back to a smooth state (blink!) at frame no.
> 250,
> which is a keyframe. With the DivX 5.0.5 decoder, the area is smooth, no
> such
> artifact.
>
>>> I'm using MPlayer 1.0-pre2 (couldn't try CVS as it doesn't compile on
>>> my
>>> machine),
>>bugreport?
>
> Strangely enough, I couldn't compile the CVS snapshot yesterday, but today
> (2003-10-14) I can. But no difference, the artifact is still there.
>
> Anyway, my system:
>
> Gentoo Linux 1.4
> kernel 2.4.20-fnk
> libc-2.3.2
> gcc 3.2.3
> GNU ld version 2.14.90.0.2
> GNU assembler 2.14.90.0.2
> Intel Celeron 1.2 GHz
> NVIDIA GeForce 2MX
> I also uploaded a log file.
>
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