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

Risto Treksler risto at elkhornbanff.ca
Mon Feb 24 20:41:42 EST 2003

On February 24, 2003 06:38 pm, Chris Pinkham wrote:
> does a shortcut on detecting a blank frame and also checks for
> commercial lengths in a specific order.  Since most (U.S.) commercials
> are 30 seconds in length, it checks that first.  Then it checks 15
> then 60.  It only scans 2 seconds worth of video for each of these.
> This seemed to speed it up quite a bit on mine.  The patch will also
> turn on some status messages to show what it's doing.  It turns on
> the normal sliderbar that shows when you fast forward and updates it
> as it finds commercials also telling how long the commercial was.

That is precisely what I was thinking of
that it was less than efficient to check every 15 seconds

in fact I read the PDF linked from a post to this list which suggested that
most commercial breaks last at least 3 ads long

so it might make sense to check fisrst for a "90 second commercial"

ie detect blank, skip ahead 90 or even 120 seconds or so
and check for another blank, 

if found we are still in commercials(or they just ended)
from then on check as usual

if not found go back to the first blank and continue as usual

should help a lot shouldn't it?

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