08 February, 2011

YouTube's copyright protection system

Naturally, I first wanted to host my video on YouTube. However, after I uploaded it, YouTube said my video contained copyrighted material from WMG and muted the audio. Obviously it automatically matches audio in uploaded content with source songs. I'm trying to find out what triggers the system here.
  • Uploaded same video in 176x144 3GP format - NOT ALLOWED. Looks like they check all qualities, and are able to match even if audio quality is not very good.
  • Uploaded first part of my video (Love Story) - OK.
  • Second part (Just The Way You Are) - NOT ALLOWED. This is the source of the problem.
  • 32 second clip was not allowed, while 31.16 second (.16 is a decimal point, not number of frames) was allowed. Looks like the limit is around 32 seconds. I added 20 seconds of silence to a 31s clip and it was still allowed, showing that it needs the time to identify the song, and it's not just checking songs over a certain length (since a 50 second clip with 30 seconds of music wasn't recognised).
Now to the interesting part: changing speed
  • Speeding it up to 101.7% causes the video to be allowed, while 101.5% isn't enough.
  • Similarly, slowing it down to 98% makes it ok, but 98.5% isn't enough.
  • These values clearly depend on the length of the video as well, since when I uploaded the whole video at 102%, it wasn't ok, but 105% is. Interestingly, at 105% it says "matched third party content", but didn't mute the audio.

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