Setting right refresh rate for media playback = judderfree playback

I have a request. It is already now possible to do this in 0810 using MythTV video plugin for playback of video content (see links below). But it would be realy nice if LinuxMCE could do this when playing media.

I am pretty sure that all of you have some kind of juddering (or stuttering) when playing media that is 23.97Hz (Hz is also frames per second) or 59.94Hz (NTSC) or 50Hz (PAL). Try all of them and you will see that in camera pan where the movie is moving sidewards.

If you have setup 24Hz and the movie is 23.97hz, then only every 100 picture will stop for a splitsecond. So you will have to have a pan in the movie of more than 4 seconds !! At other rates the juddering might be higher! But I know for some it is REALLY difficult to see it. It is probably easier in the dark.

Here you can download some trailers to test with http://www.h264info.com/clips.html

You can use the normal LinuxMCE video playback using xine (VDPAU) to test this. The first "I Am Legend 1080p Trailer" is ok for testing - take it to 0:49 seconds and watch the top of the TV, you will see that it judders just a little when the movies pans up in the city or in the gras a little later. If you setup xorg.conf as descried in the mythtv.org link, you can setup 23.97 hz with "xrandr -d 0:0 -r 53" (can be done though ssh) then play it again and you will see that it is really smooth :-) change back to 50hz with "xrandr -d 0:0 -r 50" or 60hz with "xrandr -d 0:0 -r 51". You can pause the clip and then rewind and change forth and back. I am sure you will then see the difference.

More infos how it is setup in MythTV you can see here (important is changing Option DynamicTwinView to "true" !!! ) : http://www.mythtv.org/wiki/User_Manual:JudderFree

My xorg.conf for 0810 is here : http://wiki.linuxmce.org/index.php/Sony_KDL-46W4500

At the moment I have really nice judderfree playback of 23.97Hz materiel and LiveTV using the above setup :-) Only PAL 60Hz is not working (yet) but I might find the solution.

I suppose it should not be so difficult to test the material and use "xrandr - r 51" or whatever to change the rates. The biggest problem will probably be to change the AV wizard to support the setup of xorg.conf for this. Here I mean testing if all the modes are working.

libmediainfo0 might be usable for detection of rates : http://mediainfo.sourceforge.net/en/Download/Ubuntu