Picture Jumping / twitching when running at 1080 / 24 hz

[Avery]

Hi all,

I am new to openelec but in the main have go it installed and setup but...

I have just installed Openelec 1.0.2 onto an ASROCK ION 3d 152d system. It connects to an Onkoyo 875 then to a 24hz capable samsung plasma.

If I set the resolution to 1080 / 24hz the screen starts to twitch every second or so. This occurs when the menu page is visable and whilst playing 24hz video. The twitch / jump is constant and regular.

If I switch to 60hz, the picture is fine.

xorg.conf file:

Code:

Section "Device"
Identifier "nvidia"
Driver "nvidia"
Option "DynamicTwinView" "False"
Option "ModeDebug" "false"
Option "UseDisplayDevice" "DFP-0"
Option "NoFlip" "false"
Option "NoLogo" "true"
Option "DynamicTwinView" "false"
Option "ConnectToAcpid" "0"
Option "FlatPanelProperties" "Scaling = Native, Dithering = Disabled"
Option "ModeValidation" "NoVesaModes, NoXServerModes"
Option "HWCursor" "false"
EndSection

Section "Screen"
Identifier "screen"
Device "nvidia"
DefaultDepth 24
Option "ColorRange" "Full"
# Option "ColorRange" "Limited"
# Option "ColorSpace" "RGB"
Option "ColorSpace" "YCbCr444"
SubSection "Display"
Depth 24
Modes "1920x1080_60" "1920x1080_50" "1920x1080_24"
EndSubSection
EndSection

Section "Extensions"
Option "Composite" "false"
EndSection

Any suggestions on how to resolve this?

Thanks in advance,

Rod.

[chewitt]

If you set XBMC's default resolution to 60Hz and configure "switch resolution to match playback" (or similar, I forget the exact wording) you should have the GUI at 60fps and playback at 24fps - as long as xorg read/interprets the EDID data from the receiver correctly, which is somewhat dependent on the Onkyo receiver advertising the same resolution "modes" that the Samsung plasma offers. If things don't play nice automagically you can manually override the auto-sensing behaviour by creating a custom xorg.conf file that contains static "modeline" references for the exact resolutions you want available to XBMC. THIS is an example of my xorg file from an AppleTV box which disables EDID and sets custom modeline data. You'll need the mode data from your setup which you'll find in /var/log/Xorg.0.0.log but the essentials to crib are there.

[chewitt]

in case I mis-read the question.. if you want to prevent XBMC from using anything but 60fps, the process is the same - but you only include modeline data for the 60Hz mode

[Avery]

All the equipment is 24hz capable.

What I would like to do is use 24hz without the jumping / twitching.

Are there any settings I can tweak so as to stop the jumping whilst in 24hz mode. The jumping occures whilst in the main menu sytem and when playing a 24hz film. If I force 60 hz all is fine.

I connected the TV directly to the ASROCK and the jumping is still present. I dont have anouther 24hz capable TV to test with so not sure if its the TV or XBMC, but 24hz content is fine when played through PS3 or Sony BD player.

I'm just being a little piccy but would like to play 24hz content at 24hz.