Comment 4 for bug 1942739

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psl (slansky) wrote (last edit ):

I see this issue on my notebook too. Kernel is 5.15.0.

$ inxi -CGS
System: Host: vivobook Kernel: 5.15.0-78-generic x86_64 bits: 64 Desktop: Cinnamon 5.2.7
           Distro: Linux Mint 20.3 Una
CPU: Topology: Dual Core model: 11th Gen Intel Core i3-1115G4 bits: 64 type: MT MCP
           L2 cache: 6144 KiB
           Speed: 1060 MHz min/max: 400/4100 MHz Core speeds (MHz): 1: 1032 2: 1077 3: 1001 4: 1081
Graphics: Device-1: Intel driver: i915 v: kernel
           Display: x11 server: X.Org 1.20.13 driver: modesetting unloaded: fbdev,vesa
           resolution: 1920x1080~60Hz
           OpenGL: renderer: Mesa Intel UHD Graphics (TGL GT2) v: 4.6 Mesa 21.2.6
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$ vlc --version
VLC media player 3.0.9.2 Vetinari (revision 3.0.9.2-0-gd4c1aefe4d)
VLC version 3.0.9.2 Vetinari (3.0.9.2-0-gd4c1aefe4d)
Compiled by buildd on lgw01-amd64-060.buildd (Apr 9 2020 19:29:44)
Compiler: gcc version 9.3.0 (Ubuntu 9.3.0-10ubuntu2)
This program comes with NO WARRANTY, to the extent permitted by law.
You may redistribute it under the terms of the GNU General Public License;
see the file named COPYING for details.
Written by the VideoLAN team; see the AUTHORS file.

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Screenshot with the bug: https://08167fbae5cb7870.s3.fr-par.scw.cloud/VLC-BBB-green-acc-bug.png

Note that red mushroom is shifted down, about 10%; like the layer with red color is shifted down, so green area is at the top of video screen and you can see that colors are not right in the whole picture but that is not clearly visible. Compare with screenshot without this issue (later in the report)

When VLC snapshot is taken, the issue is not visible, like it is on screen only:
https://08167fbae5cb7870.s3.fr-par.scw.cloud/VLC-BBB-green-acc-bug-vlcsnap.png

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This is the VLC setting to replicate the bug:
https://08167fbae5cb7870.s3.fr-par.scw.cloud/VLC-BBB-green-acc-bug-v1.png
https://08167fbae5cb7870.s3.fr-par.scw.cloud/VLC-BBB-green-acc-bug-c1.png

Video sample: https://08167fbae5cb7870.s3.fr-par.scw.cloud/big-buck-bunny-30sec-800x480.mp4

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Workarround is to change HW accelerator (or to disable it) or to change Video output device; for example, "XVideo output (XCB)" works OK...

https://08167fbae5cb7870.s3.fr-par.scw.cloud/VLC-BBB-green-acc-bug-ok.png
https://08167fbae5cb7870.s3.fr-par.scw.cloud/VLC-BBB-green-acc-bug-v2.png
https://08167fbae5cb7870.s3.fr-par.scw.cloud/VLC-BBB-green-acc-bug-c1.png