[mythtv] PATCH: Commercial detection/skip using blank frames

Risto Treksler risto at elkhornbanff.ca
Mon Feb 24 22:01:19 EST 2003

> it would be better to flag blanks during recording anyway.
> Chris


Here is an attempt at a list of various ways of detecting/skipping commercials
- pulled from various sources with the help of google of course

i wonder how many are useful?

how many am i missing here?

- black frames between commercials
- audio silence between commercials
- gaps in closed captioning !! - few commercials have closed captioning
- louder audio during SOME commercials
- repeated sections of video !! throughout the recording - same ad repeaated
- repeated sections of audio in the stream !! - same ad repeated
- possible fingerprinting of known commercials
- time/duration analysis - ie. can't be longer or shorter than xyz seconds
- ignore blank frames not surrounded by other blank frames 
  at predetermined intervals
- network logo detection - not present during commercials
- frame brightness analysis
- tiny rectangle in top or bottom right corner at 30 sec before a commercial
- no commercials until xyz minutes into the show
- intervals between commercials are fairly constant in a given program
  depending on the length and type of program
- fades/wipes to black - indicate start of commercials
- hardly ever fewer than 3 ads in a row
   - check 1.5 min after z is pressed to see if still in commercials,
      if not then backtrack
- check content of closed captioning for 'spam' advertizement
- rate of scene change - faster during commercials
- distance of 'areas with lots of segmentation' from 'black frames'
- no ads on some channels
- look for fade to black and no audio, fast forwarding 3 minutes or so, 
  then back up to the last fade up and start to play
- skip 30 seconds button with possible automatic overshoot protection
- mute button ;)


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