[mythtv] A prelude to transcoding MPEG2->MPEG2

Craig Rindy developstuff at qwest.net
Mon Dec 8 16:22:20 EST 2003

Jim Paris wrote:
> GOPchop still has issues with audio sometimes, I've heard.  It doesn't
> really handle audio -- it apparently just keeps all non-video data
> along for the ride while doing his chopping and hopes that it works.

James L. Paul wrote:
> Another observation. I've spent considerable time trying to get GOPchop to 
> generate useable streams and have not yet succeeded. I haven't found a 
> multiplexer that can recognize any segments after the first cut.

This is quite odd because I've been using GOPchop for a while now to archive interview segments from talk shows and cut commercials out of The Kids In The Hall, The Simpsons, and South Park.  I've never witnessed a missing audio or sync problem using my PVR-250's streams.  It gives a warning about the missing header of course, and it has the unavoidable MPEG-2 problems of the first and last GOP of each clip.  But those two problems are handled by the "Ignore Errors" and "Drop Orphaned Frames" options respectively.  The latter option is not a solution to the latter problem, just a preference for the user to choose the lesser of two evils.  I'm quite happy with cutting on GOPs because I'm archiving stuff for myself, not doing production work, so I can tolerate the less-than-0.5-second of a commercial on the occasion when there is no black frame (in my experience:  ~30%) or when there's reverb in the audio along with a black frame.

Craig Rindy

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