[mythtv-users] commercial flagging idea - commercial"fingerprinting"

[Jeff Wormsley]

John Williams wrote:

>Another consideration is going to be the different resolutions people
>record at. If everyone used the same resolution you could choos e a
>few place son teh screen (like a real fingerprint sort of) and get a
>difference from a particular pixel or set of pixels (this should
>eleminate the contrast and sharpness settings). Then just create a
>sort of MD5 type algorthm for frames or something so you aren't
>passing the actual screen shots and thus copyrighted material. The you
>could look for a series of frames that each match the algorithm's
>results in the database for the specific cut point.
>  
>
Not sure you'd want to compare pictures to pictures.  Perhaps it would 
be better to record cutlists and fixes, and compare your cutlist to 
these.  In other words, if user A had an autogenerated cutlist I, fixed 
the errors to make II, and both lists were stored, then user B would 
compare their cutlist to I, and if it matched, apply cutlist II 
instead.  One to one, that wouldn't work too well, but if 500 people 
also had I, and 200 had went ahead and fixed it themselves to II, then 
you'd have a pretty good chance that II would work for you.  Also, you'd 
need to compare only the "show" portion, because some channels may have 
4 minute breaks and others 6 for the first break, and the opposite on 
the second, or spend more time on commercials between shows and less 
during them, but most shows have set commercial break points, so the 
parts that are the actual show would be the same length (maybe give or 
take a few seconds).  In other words, don't record cutlists as 
"commercial cut at 5:42 until 9:46, commercial cut at 15:20 until 21:20" 
and so on, but instead record "Program data segment 1 length 5:42, 
program segment 2 length 5:36" and so on.  When comparing, you'd compare 
the segment lengths you have to the segment lengths others had, then 
look up the modified segment lists those users made and sanity check 
them against what you have (with presumably less stringent checking, as 
obviously it was missed the first time). 

Also, for shows that are broken at different places by different 
stations (I see that a lot with older re-runs like original series Star 
Trek), people watching version 1 would match lists by other viewers 
watching version 1, and people watching version 2 would match lists by 
others watching version 2, and so on.  Of course, some shows may be 
split any which way, in which case you can't get a match on them.  In 
those cases, though, you are no worse off than you are now.

Jeff.