avidemuxxin’
Man, I’m stoked. 
I spent all weekend repairing my MythTV box (which, btw, I have a lot of issues with the project as a whole … but that’s another post), and I finally got it to where I want it — working partially. Anyway, I just started playing around with mencoder to see how hard it would be to convert these files to something other than mythtv’s special nuv format (must … contain … rant…), and it actually turned out to be spectacularly simple. All I really have to do is just re-encode them so the AVI index is rebuilt.
The really cool part is coming up next though. I wanted to strip out the commercials myself, and at first I started thinking of how I could do that with mythtv’s commercial flagging. After all, it does just store the cutlist in the database, right? For the record: yes, it does, its in the recordedmarkup table, which took me a while to find out. Well, after my average research time of 2 seconds, I couldn’t find an easy intuitive way to use that to tell mencoder when to cut the video into pieces. I had heard of avidemux before, but last time I tried it (back when I was using Mandrake … eek. Nothing wrong with MDK, that was just a loooong time ago), it only crashed and burned horribly. I figured this was a good a time as any to give it a swirl.
And man, it works great. There’s this great feature it has “skip to next black frame” which pretty much finds the commercials for you. Then just set marker A and B at the start and stop of each break, cut it, and save the file and you’re done! All you need is about 15 minutes each to re-encode each NUV and then maybe 2 minutes to manually cut them, but you’ve got a great perfect looking pristine TV episode. Sweet. 
I should mention that I already know about nuvexport, but I’ve never had much luck with that either. If anyone’s interested, here’s a raw howto I actually got this far:
- Set mythtv to keep original recordings (they’ll be saved as foo.nuv.old) or just don’t transcode at all
- Reencode from an MPEG4 NuppelVideo to an MPEG4 AVI, video only: mencoder foo.nuv.old -ovc lavc -oac copy
- Run avidemux2 on the AVI, cut out commercials and reencode the audio to mp3 (usually PCM audio works too, but sometimes it gets scratchy).
May 29th, 2006 at 9:25 am
Not sure what version of myth you’re running, but in the SVN version there’s a “lossless transcode” option, that will apply a cut list to a recording. It might do commercials automatically too (haven’t tried). That would remove one whole step from your process, and probably be a bit easier.
One cool thing to note, is that if you have an MPEG2 capture card, myth’s nuv format isn’t used, it just stores things as mpg’s.
May 29th, 2006 at 12:34 pm
I’ve tried that, and anytime I do any kind of transcoding, it throws the AV out of sync. So, that’s why I have to resort to such odd methods.