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

[Bryan Mayland]

Geoffrey Hausheer wrote:

>Add the following line around line 950 (right after where c->qmin is set):
> c->flags |= CODEC_FLAG_INTERLACED_DCT;
>
>That is just a hack.  It actually needs to be properly detected, but
>I'd like validation that it actually fixes the problem people have had
>with ugly images.
>  
>
    I tried adding this interlaced_dct line with 0.12 and the same cut 
from before (300-390).  Frame 297 is ok, 298 (I) block artifacts, 299 
good-looking I frame from after the cut, 300 is frame 298 again, then 
301 starts B frames that look bad and doesn't clear until close to the 
next I at 315.  This is viewing frame by frame with VirtualDubMod.  
Could it be a problem with its stream vs presentation order?