Public bug reported:
Configuration:
Kubuntu 8.10 (AMD64 version) on AMD Athlon x2 3800+ CPU (dual-core CPU). ATI
x1300 videocard with proprietary drivers. Desktop effects in KDE are on.
Players tested: virtually all tested. I'm generally prefer Mplayer or VLC and
both are affected as well of course. This also occurs in Ubuntu 8.10 AMD64 as
well and in many previous OS versions.
Problem:
When you have desktop effects switched ON (in KDE4 or with Compiz) and
therefore composite mode in use, you generally out of luck with video playback.
The ONLY output method that is willing to work properly in such scenario is
basic X11 output method. It will work BUT it is very slow and causes awful CPU
load by X server process (when playing high-resolution video, load can go as
high as 40% of CPU, i.e. nearly 80% of one of cores wasted JUST TO DRAW VIDEO
FRAMES TO THE SCREEN).
Attempt to use any more advanced output methods like xvideo, OpenGL or similar
will work and CPU load is reduced. For example xvideo playback loads CPU with X
server process only by some 10% on same scenario (so, it is nearly 4 times more
efficient for me). But any such method usage leads to awful tearing and
blinking so I can see partially drawn frames and their edges and so on -
generally frames are displayed without regard to syncing with monitor's frame
rate anyhow. This leads to very annoying blinking on playback and video is
generally unwatchable.
Workaround:
If I'm disabling desktop effects, I can use Xvideo or GL video outputs without
any problem and enjoy by fast video playback with relaxed CPU load. However
obvious disadvantage is that I can't use desktop effects anymore (i.e. this
setting corresponds to "no effects" for Compiz).
So, either you can use desktop effects OR you can enjoy by fast video
playback. But not both in same time.
Some details:
This is long-standing and well-known problem with Linux distributions, affect
other Linux distributions as well.
This bug also affects Nvidia cards users as well: see bug 151674 for example.
So I believe that statement in bug 151674 that bug is in Nvidia driver itself
is not so true and other drivers are affected (ATI at least affected too) or it
is not a video card driver what causes this problem.
Note: fixing this bug could be not an easy task (it is reasonably known
in Linux community but I never seen any good solution on this issue
except of obvious choice: either you have cool desktop effects OR you
have good video playback but not both in same time). It is mandatory to
fix it to have real success on desktop. Right now users often prefer to
use Windows to watch videos due to such issues.
My system information (if needed, however issue occus on many other
configurations as well):
$ cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=8.10
DISTRIB_CODENAME=intrepid
DISTRIB_DESCRIPTION="Ubuntu 8.10"
$ uname -a
Linux ath64 2.6.27-11-generic #1 SMP Fri Dec 19 16:29:35 UTC 2008 x86_64
GNU/Linux
$ lspci
[...skip...]
06:00.0 VGA compatible controller: ATI Technologies Inc RV515 [Radeon X1300]
06:00.1 Display controller: ATI Technologies Inc RV515 [Radeon X1300]
(Secondary)
[...skip...]
** Affects: ubuntu
Importance: Undecided
Status: New
--
Awful video tearing+blinking when using any output method except X11 in video
players.
https://bugs.launchpad.net/bugs/315267
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