[mythtv] New MPEG2 commercial-cut code ready for testing

[Geoffrey Hausheer]

On 11/13/05, Stuart Auchterlonie wrote:
> On Sun, Nov 13, 2005 at 09:15:49AM -0800, Geoffrey Hausheer wrote:
> >
> > if it doesn't work, I'll need a gdb backtrace.
> >
>
> I've just gone straight for the backtrace.
> It looks like there is an invalid AVFormatContext being
> passed in, so when it attempts to use it things fall apart.
>
This should be fixed in 0.8

> I'm volunteering for extensive testing of this tool as I want
> to be able to get to a point where I do an MPEG - MPEG
> transcode to dump all commercials, then convert the result
> to a DVD compliant stream.
As I've said in the previous thread, this may not be so easy.  If you
start with a DVD compliant stream, it should work pretty well, but
depending on your locale, it can be pretty difficult to get a good
starting place.  For instance:  In the US, the DVD spec requires that
you have either an AC3 or PCM stream, with an MP2 stream being an
optional additional stream.  As far as I know everywhere else in the
world, it is the opposite (MP2 or PCM are required, AC3 is optional). 
I am not sure what the constraints on GOP structures are yet (since
this code doesn't insert them except after a cut-point, you need to
ensure the structure of the stream is correct to start with).  And it
seem sto all come down to compliance.  I have spent a lot of time
trying to generate multiple-player compliant DVDs, and found it to be
quite tricky.  Many players are picky about the AC3 thing above
(though many aren't), some don't like encdings from liba52 (or
bbmpeg), but work ok with commercial encoders, I normally need ot
reencode to meet the resolution requirements which gets me the correct
GOP structure for free, but haven't had much luck copying directly
from a PVR250 output to DVD.  I guess it all depends on what works for
you.

But I'll be happy to try to fix things as long as I can get good debugging data.

.Geoff