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I used to run XBMC repo-updated with Xubuntu 9.10 on an AMD Athlon XP with a GeForce MX440 video card in 1024x768 without problems.

Now I run XBMC from the same repo with Ubuntu 9.10 on a Pentium 4 with a GeForce 5500FX video card in 1440x900. I have two TwinView clone monitors which are native 1920x1200 and 1680x1050 but both are too high for the 5500FX to do fluent playback. 1440x900 or anything lower works fine.

At random times, the flicker and tear (you can see a "stairway" in the flicker) suddenly start. Stop/pause/menu/anything doesn't stop it. Except for pressing backslash (\) twice leave and enter fullscreen again.

This is annoying because I prefer to have no keyboard attached on this media center, and there is no backslash on my remote.

Any ideas as to what's the cause of this and how to fix?

Download this movie and see for yourself.
XBMCflicker.mp4

(I used big letters so that people who came here but didn't want to read the thread could still be interested in checking it out.)

Turn off desktop effects in ubuntu aka Compiz Fusion they tend to fight for fullscreen since they are both opengl apps

Desktop effects are already off.
Plain metacity.

Seriously, no one has this problem?

I've just done a CLEAN install with Ubuntu 10.04 and XBMC from the lucid repository, and I've got the same problem. This is very annoying, I don't use XBMC anymore because I rather do old fasion browsing on my other computer through samba everytime I want to watch something than to have a keyboard attached and press \ twice every ~5 minutes.

I think this is an XBMC bug because the flicker is also in the menu, except it doesn't flicker black, but the background image flickers making the grey skin color come through instead. (As if only the picture layer flickers, not the entire menu)

It's also not monitor related because both attached (different) monitors do it exactly the same.

This is clearly a bug.

Trac bugreport -> http://trac.xbmc.org/ticket/9199

Can you disable flipping for opengl in nvidia-settings and check if that fixes anything.

cowfodder Wrote:Read This

Oops I forgot about the debug log.

Confluence @ P4


9.11 R26018 (Compiled May 4 2010)
2.6.32-22-generic-pae

There is no crash/backtrace.

But I cannot enable debug logging.
When I turn on debug logging (with the osd), the flicker does not appear.
Or limited time testing was coincidental.

bobo1on1 Wrote:Can you disable flipping for opengl in nvidia-settings and check if that fixes anything.

It takes a few days before I'm sure and it's not coïncidental, but it looks like you're right. I wish someone had said that a month ago!

What's that option anyway? Still, it's something XBMC doesn't have to do. When debug logging is enabled, I do not get the flicker, even if flipping is enabled.

It looks like the front and backbuffer are flipped while the gpu is still drawing.
I'd stay away from nvidia twinview, the best option is to use two separate X screens.

bobo1on1 Wrote:Can you disable flipping for opengl in nvidia-settings and check if that fixes anything.

on my setup

flipping off = perfect playback at 23.98Hz, but tearing in 50Hz

flipping on = perfect playback at 50Hz but 23.98Hz drops 1 frame every minute.