[mythtvnz] Commercial Flagging

[Tony Sauri]

On Wed, 17 Aug 2011 22:15, Bruce Wilson wrote:
> maybe I have the wrong settings? I have set it to "all available methods"
>
> On 17 August 2011 17:38, Nick Rout <nick.rout at gmail.com> wrote:
> > On Wed, Aug 17, 2011 at 5:24 PM, Bruce Wilson <acaferacer at gmail.com>
> >
> > wrote:
> > > Hi,
> > > I have found the commercial flagging in MythTV does not work that
> > > great.
> >
> > Has
> >
> > > anyone done any work on optimising it for NZ?
> >
> > Always worked well for me.
> >

In common with others I have noticed very patch performance  ( I only receive 
DVB-T programmes and cannot say whether my comments will also relate to DVB-S 
recordings or capture from the back of a SKy Box)  Anywas I have been doing a 
little bit of digging (code reading) to work out how the magic is done  and 
try to understand what could be done to make things better.

There are three main methods provided:
	black frame detection
	scene change, and
	logo detection

My comments:
	I dont think any network in NZ consistently uses black frames before and
	after every commercial break.

	Scene change does not seem to be a real starter

	Logo detection seems to be the technology most likely to work in NZ 
	However as it works by edge-detection of the network logo it seems highly
	dependent upon the intensity (and size ?) of the logo, so stations like
	Prime and C4 with large and less transparent logos seem to have their ad
	breaks more successfully detected than say One or Three. 

	There also seems to be a problem that if the first x mins of a recording are
	only ads (because of pre-roll etc) then the detector decides there are no
	logos and gives up.

Can we make the detector smarter to suit NZ?  I am not sure ... I have thought 
of a few things but they are only tinkering around the edge and may introduce 
more problems.

For now though because most ad breaks are some multiple of 30 secs I have a 30 
sec forward skip  and a 10 sec backward skip on my remote so a few presses of 
the button and were are back in business again!

Regards

Tony