[doveman2]

Checking my files, it seems that most of it is indeed 23.976fps, with my own TV recordings and iPlayer downloads being 25fps and DVDs 29.976fps. What I could do with MediaPortal is speed up the 23.976fps to 25fps and sync it with the TV running at 50hz and likewise with the 29.967fps DVDs, speed them up to 30fps and sync them with the TV running at 60hz, with MediaPortal able to switch the display/TV to the appropriate refresh rate, so I wonder if XBMC/OE can do something similar yet?

The 29.976->30 fps and 23.976->24 fps happens automatically bu adjustments to hdmi clock.

24->25 fps is too great for changing hdmi clock, and needs to be done by resampling audio. This cannot be done when passthrough is enabled.
It could in theory be done on the Pi when passthrough is not used, but I've never tried it.

OK, thanks, that's good about the 29.976 >30 fps thing. I'll have to check how 23.976 >25 fps with MediaPortal looks compared to playing it on the RPi but I imagine it will help a lot with the judder I'm seeing, so if it could be added as an option on the RPi, that would be nice. I'm not using passthrough myself, just HDMI audio to my TV (which has an analog output, so I'll probably hook that up to an amp at some point for better sound quality).

In fact, I've just checked the manual and it seems my TV does support 1920x1080p/24hz and if I set this in XBMC the TV reports it's using that, so in theory I might be able to play my 24fps content OK if XBMC will upscale it from 480p to 1920x1080p. However, XBMC isn't switching resolution/hz at all at the moment and whatever resolution I set, that's what it stays on whatever is being played, so if I set it to 1280x720@50hz, it stays on that when playing the 480p/23.976fps content.

I've noticed that the RPi defaults to RGB limited (can clearly be seen with the Black Clipping test pattern as even with brightness on max, nothing below 16 flashes and likewise with the White Clipping pattern, increasing Contrast doesn't make the bars above 235 change) but can be set to RGB Full with config.txt using hdmi_pixel_encoding=2 but I'm not sure if I should do this.

At the moment, if I change from 1280x720@50hz to 60hz it also forces the resolution to 1366x768 with a greyed out 60hz and there is a change in brightness. The TV supports 1280x720@60hz so I don't know why XBMC isn't allowing me to select it. The black menu background is greyish at 1280x720@50hz and changes to more of a proper black when it switches to 1366x768 but this appears to only be noticeable when I have the TV set to RGB Full and not if I switch it to RGB Normal, so what might be happening is that for some reason, the RPI is changing it's RGB output mode when switching to 1366x768. Obviously I can calibrate the TV so that black is black at 1280x720 but then it will be too dark at 1366x768 so I can only calibrate to one or the other and it would be helpful to be able to test different resolutions without the output levels changing like this.

With it set to 1920x1080 I can set it to 50 or 60hz no problem.