[mythtv] Thoughts on new commercial detection option

Chris Pinkham cpinkham at bc2va.org
Thu Dec 2 18:28:05 UTC 2004

> I have noticed that more and more shows are shown in letterbox (in 4:3 
> format) and have black bars on the top and botton during the show but 
> switch to full 4:3 during commercials. Would it be possible to add 
> another commercial detection scheme that looks for the letterbox format 
> with the black bars, and if present goes back to the beginning of the 
> show and flags commercials when the black bars go away?

Eventually I hope to have most/all detection methods used concurrently
to try to get the best detection possible.  Something like a bitmask
for each frame of video saying which detection methods were relevant
for that frame.  Sort of like this (if all these methods are coded):

0x0001 = frame is blank
0x0002 = frame is a scene change
0x0004 = logo present on frame
0x0008 = aspect ratio changed at this frame
0x0010 = audio silent
0x0020 = etc.
0x0040 = etc.
0x0080 = etc.

So a frame with a mask of 0x15 would indicate a silent black frame with
the logo present.  Very likely that frame is on a commercial boundary.

I've started work on changing the current code to work towards something
like this but haven't had much time so it's nowhere near there yet.



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