[mythtv] mythtranscode -> avi

[Chris Petersen]

So with a lack of support from mplayer for myth's nuv file format, would 
it be possible to get mythtranscode to just output the nuv AV data into 
an AVI container?  This seems to be the single most requested feature 
for nuvexport (seconded by dvd export), and frankly it would make other 
exporters a lot easier to write (eg. could use transcode)

Anyway, just doing some thinking about this whole thing.

-Chris