Bug 19856 - xvideo: broken bilinear filter for the red color component
Summary: xvideo: broken bilinear filter for the red color component
Alias: None
Product: xorg
Classification: Unclassified
Component: Driver/intel (show other bugs)
Version: git
Hardware: Other All
: medium normal
Assignee: Wang Zhenyu
QA Contact: Xorg Project Team
URL: http://bugs.debian.org/cgi-bin/bugrep...
Keywords: regression
Depends on:
Reported: 2009-01-31 03:43 UTC by Brice Goglin
Modified: 2009-08-05 15:12 UTC (History)
1 user (show)

See Also:
i915 platform:
i915 features:

visible problem with filtering of red color component (559.36 KB, image/png)
2009-02-01 13:47 UTC, Rene Pavlik
no flags Details
xvideo output - more visible problem (815.35 KB, image/png)
2009-02-06 10:26 UTC, Rene Pavlik
no flags Details

Description Brice Goglin 2009-01-31 03:43:49 UTC
SkyRaT <skyrat@email.cz> reported this bug in the Debian BTS recently.
He's running Xserver with Intel 2.6.1 on 2.6.26-1-amd64 on
a "Integrated Graphics Chipset: Intel(R) G45/G43".

He says:
"This issue arose after the latest upgrade and was not present before.
One can clearly see, when there is a red object in a playing video,
and has the window enlarged or placed on the full screen, the red
object is being "pixelized" instead of blurred by the bilinear
filter as other colors. For sure, the red component is in almost
every color, so the whole screen is being influenced, but it is not
so apparent."

Config and Log available at
Comment 1 Gordon Jin 2009-01-31 04:16:57 UTC
What's the working version of xserver and xf86-video-intel?
Comment 2 Rene Pavlik 2009-02-01 13:47:51 UTC
Created attachment 22443 [details]
visible problem with filtering of red color component
Comment 3 Rene Pavlik 2009-02-06 10:26:37 UTC
Created attachment 22656 [details]
xvideo output - more visible problem

the previous screenshot was made using the "-vo gl" option to mplayer.
The current one was made using "-vo xv"
Comment 4 Brice Goglin 2009-02-08 12:53:32 UTC
Rene isn't sure which version was working fine before this regression appeared. 2.5.99 was probably fine.
Comment 5 William 2009-04-18 02:32:01 UTC
I've had this problem ever since I started using this driver (about version 2.2.0). The overlay video has always worked much better for me (no tearing / red-pixelation).
Comment 6 Eric Anholt 2009-08-05 15:12:07 UTC
commit 79b6851148574419389ac8055b0c31b8bdac3ab3
Author: Eric Anholt <eric@anholt.net>
Date:   Wed Aug 5 12:45:16 2009 -0700

    Fix sampler indexes on i965 planar video.
    We only set up one sampler, because all of our sampling is the same.  By
    using a non-zero index for the other two samplers, we'd dereference (likely)
    zeroed data, resulting in using NEAREST filtering.  This was a regression in
    40671132cb3732728703c6444f4577467fa9223f which incidentally switched from
    having 6 samplers to 1.
    Bug #22895, #19856

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