[mythtv-users] Commercial Flagging Problem

Kevin Kuphal kuphal at dls.net
Sun Jan 30 12:27:02 EST 2005


Chris Pinkham wrote:

>It is definitely an art not a science, and to make matters worse, every
>capture card is different when capturing analogue TV.  So, for
>instance on one user's card #1 a black/blank screen is all values 0-10
>but on another card in the same computer, it could be 60-70.  I tried to
>code around some things like this in current CVS, but there are still going
>to be some differences that I'm not accounting for.  This is one reason you
>could have 2 people recording the same show and it works great for one person
>but not-so-great for the other person.  Add to that the fact that like you
>say the people making the content and stations don't want us skipping
>commercials and it makes it practically impossible to get it working
>perfectly.  One of the things that I noticed that started breaking
>commercial flagging using the blank-frame code in 0.16 was the fact that
>CBS started putting their logo up during the blank frames.  Since the old
>code didn't know about the logo, it would detect the frame as being
>non-blank and it would realy mess up the commercial detection.  In current
>CVS, I try to work around that and it seems to be doing much better.
>There is also a new "ALL" method which tries to use all available info
>from the recording to find commercials.  The ALL method is extensible so
>I'll be adding more things to it in the future to help better detect
>commercials and eliminate false positives.  I've got code started in
>my source tree to try using aspect ratio changes to help detect when
>commercials start and stop.  There are also a few other detection ideas
>on my TODO to add that will help the ALL method be more accurate.
>  
>
Just a point here.  I've been using the new All method in CVS for a few 
weeks now and I've found that shows that previously detected horribly 
(Enterprise, West Wing) are now detecting as flawlessly as other shows 
that have worked for a long time.  This feature is a definite 
improvement here in detection.

Kevin


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