[mythtv-users] Commercial detection idea

Steve Christall mythtv at mctubster.com
Fri Apr 8 09:30:59 UTC 2005

Brad Templeton wrote:

> And it might also be worth looking not just at the lulls but in sudden
> changes in the mean energy.
> The rules prohibit commercials from actually being louder than the show,
> but that's the peak they measure.   The show uses the peak only for loud
> things, like explosions, but the commercial tries to get as close to it
> as it can.  At least some do.
Yes, don't get me started how much they crank the volume of commercials 
here in the UK.

As it stands the commercial detection code in the UK (CVS as of end 
Mar05) basically doesn't work.  Maybe the channels in the US dont mix it 
up as much as here?

Anyway back to the sound.  Yes the average sound levels during the ad 
breaks really crank (at least in the UK).  To me it appears that all ads 
/ promos are run through a compressor, decreasing dynamic range and 
increasing the average energy much much higher that the shows.  This 
combined with statistical analysis ... eg commercials run 3-4 mins, four 
or six breaks an hour, I would have thought this would work.

I can't code to save myself, but I can and will have a look at the 
average levels of a statistically significant number of shows to see if 
it is obvious.

Stay tuned

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