[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


agreed


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 ;)


references
http://www.dli2.nsf.gov/dlione/berkeley/wachtler/img015.GIF
http://www.cdvp.dcu.ie/Papers/ICEIS2001.pdf 
http://www.toonarchive.com/karin/
http://www.gossamer-threads.com/archive/Misc_C2/MythTV_F10/Closed_captioning_and_commercial_detection_P2164/
http://www.kom.e-technik.tu-darmstadt.de/acmmm99/ep/mcgee-demo/
http://www.google.ca/search?q=cache:OvnnaUSE_5cC:www.gossamer-threads.com/archive/Misc_C2/MythTV_F10/roadmap_to_install_mythtv_on_mdk_8.2_P1776/+%22commercial+removal%22+vcr+&hl=en&ie=UTF-8
http://www.google.ca/search?q=cache:JPkCX0I88GIC:www.media-awareness.ca/eng/news/news/columns/vchip.htm++%22out+commercials%22&hl=en&ie=UTF-8



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