Transcode nuv files to divx
In order to make your recordings usable to other programs than mythtv you can use nuvexport choose the show specified and provide the proper settings. I like to use 244 for sound and 2520 video bitrate.
You can also use mencoder I use the following settings.
mencoder input.nuv -ovc lavc -lavcopts vcodec=mpeg4 -vop scale=720:480 -oac mp3lame -o output.avi
This gives a .avi file of aboute 700Mb for about 1½ hour of recording.