[mythtv-users] MPEG2 cutting script complete

Chris Petersen lists at forevermore.net
Mon Aug 16 14:50:14 EDT 2004

> I'd like to inquire about something vaguely related to this:  From this thread 
> I understand it is impossible to get rid of commercials without transcoding 
> the mpeg2 stream to mpeg4, is that correct ?

It's impossible directly within mythtv.  This addition to nuvexport lets 
you cut commercials without transcoding the mpeg2 source.

> If so, I have a bttv card and plenty of CPU, so I record in mpeg4 and then 
> transcode to get rid of the commercials, and I still have meg4 then.

You can transcode all you want.  The nice thing about the mpeg4->mpeg4 
commercial cutting is that it does NOT transcode the whole stream (thus, 
you don't lose quality), but only the portions right around the cut 
points where a few frames need to be "fixed" (basically, so they match 
up better).

> So is it really true that one cannot transcode mpeg2 -> mpeg2 but one can 
> transcode from mpeg4 -> mpeg4 ?   (Why is that? Lack of a fast mpeg2 codec ?)

I believe it's "lack of an mpeg2 codec" -- fast isn't an issue with 
transcoding.  There *was* intent to add this, but I haven't heard 
anything about it in a long time.


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