[mythtv-users] Re: Transcoding... first blood (Transcoding resulted in larger file)

[Chris Vargas]

If you want to make a DVD from your recordings, and
you're using a PVR-250 or -350, your recordings are
already in MPEG2 format, so there's no real need to
transcode.

Default setting is to transcode MPEG2->RTJPEG which
indeed makes a much larger file (great for clean
editing, not so great for disk space):

http://www.mythtv.org/docs/mythtv-HOWTO-21.html#ss21.13

Now, since the commercials only get cut out when you
transcode, you're really looking for something that
will edit the MPEG2 according to the commercial cut
list while leaving the file as an MPEG2. Someone just
announced such a script to the list a couple days ago:

http://gossamer-threads.com/lists/mythtv/users/80280