[Openchrome-users] HW mpeg2 decoding artefacts

[Thomas Hellström]

Andrey Liakhovets wrote:

>I've got 16x16 square artefacts while playing MPEG2 video
>on EPIA SP8000 with `mplayer -vo xvmc -vc ffmpeg12mc'.
>There are no artefacts when I play it with `mplayer -vo
>xv'.
>
>These are video fragments (856x768, 33 frames, 1.2 Mb
>each):
>
>        http://rapidshare.de/files/13628854/01_33.avi.html
>        http://rapidshare.de/files/13629424/04_36.avi.html
>        http://rapidshare.de/files/13629742/07_39.avi.html
>        http://rapidshare.de/files/13629988/10_42.avi.html
>        http://rapidshare.de/files/13630257/11_43.avi.html
>        http://rapidshare.de/files/13630931/13_45.avi.html
>
>Brief description:
>-----------------------------------------------------------
>  MPEG2     Frames with  Approximate artefacts coordinates
>  video     artefacts    (relative to 856x768 window)
>-----------------------------------------------------------
> 01_33.avi    22-31     X=480..495, Y=656..671, then
>                         minor shifting and transformations
>                         and additional squares at
>                         X=496..511, Y=624..639 and
>                         X=496..511, Y=640..655
> 04_36.avi    10-16     X=480..495, Y=480..495
>                        X=464..479, Y=528..543
>                        X=464..479, Y=544..559, then
>                         minor shifting and transformations
>                         and additional squares
> 07_39.avi    10-16     X=464..479, Y=592..607, then
>                         minor shifting and transformations
>                         and additional squares
> 10_42.avi    14-16     X=512..527, Y=576..591, then
>                         minor shifting and transformations
> 11_43.avi     5-16     X=432..448, Y=672..687, then
>                         minor shifting and transformations
>                         and additional square at
>                         X=400..415, Y=688..703
> 13_45.avi     4-16     X=448..463, Y=640..655, then
>                         minor shifting and transformations
>-----------------------------------------------------------
>Nearly all artefact squares look like
>some 16x16 part of a frame.
>It seems that artefacts disappear at (or after?) key frame.
>
>Can somebody confirm this?
>
>For me, this looks like a hardware motion compensation bug.
>Am I right?
>
>If somebody is interested,
>these MPEG2s were made from 45 frames at
>     http://rapidshare.de/files/13632732/frames.tar.gz.html
>each MPEG is made from the 33 frames indicated in its name
>with the command:
>  mencoder mf://*.jpg -mf fps=30 -ovc lavc -lavcopts \
>        vcodec=mpeg2video:\
>        vrc_buf_size=1835:vrc_maxrate=9800:vbitrate=8000:\
>        keyint=15:trell:mbd=2:precmp=10:subcmp=10:cmp=10:\
>        dia=-10:predia=-10:cbp:mv0:vqmin=1:lmin=1:dc=10
>
>I used MPlayer-cvs20051214 with
>`mplayer-uni-20050926.diff',
>Xorg 6.9.0, kernel 2.6.14.
>Xorg logs are at:
>  http://rapidshare.de/files/13644433/X_log.tar.gz.html
>(I've tried 1024x768x24 and 1024x768x16).
>
>I've got the same results with VIA's driver & VeMP:
>`CN-CLE-PMXF40056-kernel-src_20050124.tgz',
>`VeMP-patch-MPlayer1.0-pre5_v1.2_20050616',
>XFree86-4.3.0, kernel 2.4.26.
>
>Andrey Liakhovets
>
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>openchrome-users at openchrome.org
>http://wiki.openchrome.org/mailman/listinfo/openchrome-users
>
>  
>
Hi!

I can't see these artifacts neither with hw decoding xine nor with 
mp2player. Could they be an mplayer issue?

/Thomas