[Redsandro]

Hi,

I've recently switched from an Athlon XP/MX400 running Xubuntu to a much faster P4 2.4GHz with more memory (1G) and a better videocard (FX5600) running Ubuntu for using XBMC.

Now any video I have that plays back fine on VLC or Totem Movie Player plays back choppy in XBMC. I have the version in the Ubuntu 9.10 repository. The video's play back fine on my older Media Center.

It's like it plays back 6 frames slow and then skips 3 frames to make up for it all the time.

Don't VLC and XBMC use the same libraries? I think there's a simpler cause but I can't figure it out.

[b7ll]

I read that XBMC doesn't like compiz, which may be installed on your ubuntu distribution.

[Redsandro]

Isn't that installed by default in Ubuntu? But I purposely disabled desktop compositing.

[b7ll]

I think it depends what desktop is installed (kde, gnome etc...) I am a bit of a noob where linux is concerned, I tried a few different installs and noticed xbmc and mythtv were better on mythbuntu than ubuntu 9.1 'out of the box' which I think (but could be wrong) was down to the desktop or compiz.

[Redsandro]

I think running Gnome shouldn't be a problem, it's the most commonly used desktop manager for linux. Video played back fine on Xubuntu on a slower machine (XFCE) and it also had Compiz, also disabled but still. If it's interfering configuration because of compiz I should have seen it on that machine, I think.

I don't know where to look, but I don't think Gnome is the reason. The machine far exceeds the power to play back a basic XviD, even with some OSD. This is a silly problem, but a serious one nontheless.

[b7ll]

Have you tried xbmc live on a cd or usb stick to see if it works ok ?

[Redsandro]

I was just about to test it, I downloaded and burned XBMC Live 9.11 from here, until I found something else out.
(Totally unrelated: What's up with people zipping files that are uncompressable?)

I have two monitors attached as Twin View. That's because I usually work on two computers. Main computer main screen, Ubuntu computer Right screen. Then when I want to watch something XBMC, I press the source button on my main screen (which is bigger) so it displays a nVidia TwinView clone of the right screen. Both screens are output as 1680x1050.

Now when I remove the TwinView clone, video plays back normally. It goes back to choppy when OSD is displayed (e.g. when you move the mouse), but that's acceptable. When I go back to windowed mode (which seems to be 720x480 or something, must be a default because I never chose something), video is normal even if there's OSD.

Either way would be fine, but I need to automate this. Any work before someone here can watch something when I'm not working takes away the charm of a media center. My first guess would be xrandr but ever since xorg.conf became automated it just displays my native resolution. Guess I can change that.



-edit- after some more fiddling.. let me talk to myself.



Apparently the GeForce FX 5500 hasn't got enough juice to output two 1680+ signals. At least not using XBMC, any other player and it works fine. I know I said FX 5600 earlier, that's what it sais on the print. But nvidia-settings detects it as FX 5500.

Logical 16:9 / 16:10 computer resolutions:

1920x1200
1920x1080
1680x1050
1440x800
960x540
840x525
720x450

Anything below 960x540 sucks (unless you got superman eyes or you're not sitting 4 meters away) but using two 1440x800 outputs works fine, even with OSD. Use that one TwinViewed with XBMC.

Now whether you'll want to use xrandr or XBMC's native video resolution setting, you're gonna need to put it in your xorg.org anyway.

I'm not gonna bore you with my xorg.conf because it is personal (to your computers' hardware) so get one with your daily usage settings (e.g. save from nvidia-settings) and add the metamode for XBMC like so:
geany /etc/X11/xorg.conf (or any editor)

Code:

Section "Screen"
    Identifier     "Screen0"
    Device         "Card_NV"
    Monitor        "Panel_LG"
    DefaultDepth    24
    Option         "TwinView" "1"
    Option         "TwinViewXineramaInfoOrder" "CRT-0"
    # RED 2010-03 added, metamodes needed or XRANDR will not work.
    Option         "metamodes" "CRT-0: 1680x1050 +0+0, CRT-1: 1680x1050 +0+0; CRT-0: 1440x900 +0+0, CRT-1: 1440x900 +0+0"
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection

Now, for occasional TwinView watching, you're gonna want to batch-run xrandr prior to launching XBMC and once after quitting.
(not tested, works only for resolutions set in metamodes
launch-xbmc.sh

Code:

xrandr -s 1440x900
xbmc
xrandr -s 1680x1050

For permanently setting this, you can choose the metamode in XBMC options after you've restarted X (ctrl+alt+backspace if you've enabled that in keyboard settings).

(I am talking to myself this way because it makes sense if someone googles here with the same problem. )

Yay, glad it finally works!