[nickr]

There is no frame-packed restriction as such in XBMC. If you look around here there are windows builds that do it, on certain nVidia cards with appropriate drivers.

What doesn't work in mythtv is MVC decoding, because ffmpeg doesn't do MVC decoding, and XBMC is based on ffmpeg.

There are also instances of FSBS (and presumably HTAB) working on mythtv, and if you look you'll find a thread about that.

The difference between MVC (an encoding technology) and frame-packing (an output technology) is little understood it would seem.