So I've tried;
- Upgrading to latest nvidia driver v285.05.09 via PPA
- Playback in MythTV player instead of mplayer (all VDPAU profiles low/normal/high)
- Disabling compositing and enabling triple buffering in xorg.conf
- Setting gpu+cpu scaling to max performance
So, these HD DVB-S(2) recordings are interlaced right? If bluray rips and other progressive HD/high bitrate videos play back fine, then the problem lies with deinterlacing?
Even if I set MythTV plaback to use the low end deinterlacing, it makes no difference.