[mythtv] New Method for Commercial Detection.

Buzz buzz at oska.com
Wed May 3 06:17:19 UTC 2006

The existing MythTV commercial detecting code is far from perfect (here in
AU anyway), but it typically does at least narrow the field on the
video/audio stream down to smaller pieces (ie less places to look)  

Suggestion for blending the two commercial detection techniques....:

A) run new audio analysing commdetector
B) if A) identifies known commercials then run existing MythTV commdetector
over slightly broader region (+5 minutes either side at most?)
C) if A) doesn't detect any known commercials then run existing MythTV
detector over entire recording. (as per now)
D) if B) identifies broader commercial region than A) (ie new ad/s at
start/end), consider it a new region/commercial to "teach" to audio
analysing commdetector.
E) if D) results in a new region/commercial then fully trust(ie put/activate
it in the fingerprint database) that audio fingerprint once it is seen
elsewhere in a different program/episode (if the program is different, but
the fingerprint is the same, it's not part of the program, and must be a

This may mean that a comercial is "seen" the first time, and removed after
that, but only if it occurs at the start/end of a break, and only if it's
the first time it's ever been seen ever.


> -----Original Message-----
> From: mythtv-dev-bounces at mythtv.org 
> [mailto:mythtv-dev-bounces at mythtv.org] On Behalf Of Robert Dunn
> Sent: Wednesday, 3 May 2006 3:27 PM
> To: Development of mythtv
> Subject: Re: [mythtv] New Method for Commercial Detection.
> Steve Hodge wrote:
> >> This isn't as much of a problem as you would imagine, the 
> reason this 
> >> technique can work is because commercials repeat, where as 
> programs 
> >> do not. Even if someone were to submit keys for the latest 
> episode of 
> >> a TV Show. They wouldn't detect the program unless it aired again 
> >> before the keys 'timed out' and were removed from the 
> database. Over 
> >> here there are very few TV shows which would have the same episode 
> >> aired within a couple of weeks of each other.
> >>     
> >
> > I guess you don't have Sky, Rob? What you say is only true of FTA 
> > broadcasts in NZ, and not of most Sky channels.
> >
> > Steve
> Well we do, I just never really noticed that they do repeat.  
> Believe it or not I don't watch much TV... there's too many 
> commercials =D. After further reviewing the Sky Watch you are 
> very much correct there is much more repetition than I had 
> initially thought when compared with the FTA channels. I 
> guess the issue of malicious keys would be more significant 
> than I realized, certainly an issue to be dealt with if on 
> line-collaboration was ever implemented.
> > I wonder how well it could handle previews for shows!  In AU, you 
> > often get a preview of an upcoming show as the first or 
> last block of 
> > a commercial.  And the preview can change in format depending on 
> > whether it is getting to the end of the current show or not.
> >
> > Would this be a problem?
> >
> > Whytey
> To put it shortly, possibly.  It would depend on how they are 
> structured, I will have to look into this further.
> Thanks for all the feedback guys, its good to have other 
> people pick over an idea to find the flaws =D Stitch in Time 
> and all that.
> Thanks,
> Rob.
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