Video fluency problem - gentoo vs. ubuntu
#1
Hi!

I've successfully installed XBMC on my box (E8400, 2gig ram, ati radeon 4850) on both ubuntu 8.10 and gentoo.

For the ubuntu installation I've used this page http://forum.xbmc.org/showthread.php?p=185738 (intrepid ppa), under gentoo I just did "emerge xbmc".

The problem is, that I can watch every video on ubuntu installation and it plays fluently, even the craziest 1080p clips. On the gentoo on the other hand it plays a bit choppy. Playing the same with mplayer on gentoo is not choppy at all (both -vo xv and -vo gl).

Both systems use fglrx and have the same xorg.conf. Ubuntu uses 8.543 ati drivers and 2.6.27-7 kernel, Gentoo uses 8.582 ati drivers and 2.6.26-gentoo-r1 kernel. Both have gnome installed, both play all content with mplayer/vlc/ffmplay fluently.

The emerge xbmc just checks out the latest code from the SVN and compiles that. I have tested this on two revisions, now 18868 i guess.

The difference that I have noticed about the two installations is that under ubuntu, when I go to "system info" screen in XBMC I see 100Hz refresh rate. When I go there on gentoo, I see 30Hz refresh rate.

I've already seen some posts on this forum about tearing the video due to refresh rate being to low. The question is how can I influence the refresh rate that is set by the xbmc?

I've already tried cleaning the xorg.conf, all gnome user settings and so on. I have also trying running the gentoo installation with -fs parameter and setting different resolutions with no luck - always the refresh rate is reported as 30Hz.

I would be grateful if anyone would read that and could point me somewhere.

regs!
Reply
#2
Sticky: HOW-TO post about a problem in a useful manner

First step is a debug log.

The systems, I might assume, are two separate systems, and hardware wise they are identical?

Could you make it a dual boot situation where you could test both ubuntu and gentoo on the same hardware?

The debug log would be most helpful because it will say what's doing on under the hood.
Reply
#3
You don't have vsync on, or it isn't working correctly in your ubuntu install. Though I have my doubts enabling it will do anything more than lower CPU usage a bit. Sounds to me like ubuntu knows how to set your system up better than you do. Wink
Reply
#4
O sorry forgot to add that....

http://www.qubix.pl/gentoo-xbmc.log

here is the log from the gentoo installation, that has video fluency problems.

Those are both separate operating systems on one box, dual booted. And I'm doing that exactly - I boot into one or the other and check what works and what does not.

I've looked into both logs - from gentoo and ubuntu - and I see that there is a problem with CXRandR. Is that the cause?
Reply
#5
althekiller Wrote:Sounds to me like ubuntu knows how to set your system up better than you do. Wink

True! Wink That's why I'm starting to thinking of using ubuntu daily, as gentoo <flame-war-mode>is sort of dying out</flame-war-mode> currently and the X desktops are fare more complicated to set up right now than they were 4-5 years back when I started gentoo-ing.

I tried enabling and disabling vsync in xbmc options - it did not influence anything.
Reply
#6
I'm also using gentoo and since the latest few svn updates I'm experiencing slow playback too. 1080p mkv and ts files used to play fluently on my AMD X2 box. Since I did some driver and xorg updates of late I thought that it was because of some misconfiguration on my part. I'll check my log for CXRandR problems.

Quote:X desktops are fare more complicated to set up right now
I'm experiencing it the other way round. As of late I could delete lots of custom settings from my xorg.conf file. The input devices are now all handled automatically (evdev and hal) and the monitor detection is much better also. All I have to configure are some graphics driver options.
Reply
#7
Tariella: What graphics card and drivers do you use? ATI+fglrx as me or nvidia?

Have you tested your box with ubuntu and/or xbmc live?

Regarding configuration problems: well yes, the X themselves are way much better regarding configuration. But getting compiz, gtk-engines and all working flawlessly just like in ubuntu is a tuff job, much tuffer than just installing ubuntu Smile It used to be the other way round some time ago Smile

Best regards!
Reply
#8
I have a mobo with integrated ATI HD3200. So I'm using fglrx.
The last xbmc live version I tried did not yet support this graphics device - it's been some months since that tough. I'll have to check xbmc live again, never used ubuntu (yet).

Quote:But getting compiz, gtk-engines and all working flawlessly just like in ubuntu is a tuff job...
Getting compiz to work is indeed more work than just Xorg. I installed my compiz a while ago on my desktop with nvidia graphics an it worked quite fine then, but of course I had to change the config and use an overlay.
Reply
#9
Tariella Wrote:Getting compiz to work is indeed more work than just Xorg. I installed my compiz a while ago on my desktop with nvidia graphics an it worked quite fine then, but of course I had to change the config and use an overlay.

See.... ! When I installed ubuntu 8.10, compiz works out of the box without any issues. You can even turn it on/off using gnome administration menus. Moreover, when I have compiz enabled and start xbmc, everything works nice and fluent, even thou xbmc is thought not to work in compiz environment.

ok. end of rant Smile

Conclusion - some latest svn revisions have problems working on gentoo. How can we find out why.... ?

Another question - what kernel do you use?

If you are a normal gentoo user, then you won't find problems with installing ubuntu using debootstrap on a separate partition just to test out xbmc Smile
Reply
#10
I'm running the gentoo-2.6.28-r3 kernel.

When I have enough time to do a repartitioning/new install of ubuntu, I'll give it a try.
Next thing I'll do is update my xbmc live usb stick.
Reply
#11
It seems something changed in the 19080/19081 build.

I've switched off vertical blank syncing and now it is working fluently and very ok
Reply

Logout Mark Read Team Forum Stats Members Help
Video fluency problem - gentoo vs. ubuntu0