[mythtv-users] Commflaging with 2 "logos"

Mike Perkins mikep at randomtraveller.org.uk
Wed Dec 9 10:30:02 UTC 2009

Warpme wrote:
> Hi *
> Since some time (year or two) I have issues with comm detection.
> Effectively, comm detection isn't able to detect majority of comms 
> (comms are detected in 1 show for 20+).
> I was trying select various methods - so far only logo detection gives 
> any detection (all others methods are not detecting at all).
> I remember myth 0.18/0.19 times. At that times comm detection was 
> working with  really high hit ratio.
> I think detection practically stopped to work when our (I'm living in 
> Poland) communication agency forced all broadcasters to add parental 
> rating to screen.
> Rating is small red or yellow or green triangle/square - in fact from 
> comm flagging point of view exactly the same like broadcaster logo (it 
> also appears/dissaperas exactly in the same moments during broadcast).
> So my theory is that broadcasts having 2 constant "logos" causes comm 
> flagger to fail, as algorithm assumes that logo can be only in single 
> place on screen.
> To verify this theory I need to tell for comm flagger: "watch for logo 
> only in right, upper corner"
> Is it possible at all ?
> For PoC I can hardcode such change.
> If it helps - it might be good argument to enhance comm flagger with 
> option "analyze 1[2][3][4] quarter", where 1=upper-right, 2=lower-right, 
> etc.
Interesting point raised here. Sometimes in the UK we get programs with more 
than one logo, often when they are rebroadcasts from foreign suppliers, so this 
might impact the indifferent commercial detection we (can) get here.

Big problem will be that the extra logo(s) might appear in any corner of the 
screen; in fact, for widescreen, the logo might not be in the corner at all but 
1/3 the way across.


Mike Perkins

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