[mythtv] Proposed commercial detector

Robert Tsai mythtv at tsaiberspace.net
Fri Mar 23 15:11:10 UTC 2007

On Fri, Mar 23, 2007 at 10:07:20AM +0100, Attila Nagy wrote:
> On 3/22/07, Chris Pinkham <cpinkham at bc2va.org> wrote:
> > Commercial skip has been working well enough for me lately that I
> > haven't been motivated to work on it as much as othe things like
> > Storage Groups, etc. that I have a more immediate need for.  I
> > don't think there's anything in the experimental branch for
> > ratings symbol detection either.
> Is there some kind of description about the logo detection strategy?
> I've tried to look into the code, but on the first look it was too
> obfuscated for me.
> I'm also for the rating detection, because things work a little
> different in my country, and the logo detection does not work so
> well.
> In a few words: we have fewer, but longer breaks than in the US. The
> breaks usually are built up the following way: commercial pops in
> (may there is a blank frame), and the logo is removed. After 4-5
> minutes of commercial, the station shows trailers of it's own
> programmes, and for this part they put the logo on again. In some
> cases they have trailes on the first third, then commercials, and
> then trailers again. The current logo detection get's lost quite
> often.
> On the other hand stations have to display rating logos all the time
> during a show, usually it's in the lower left, or the lower right
> corner.
> I'm not shure if the current logo detection only detects one logo on
> the screen, or is it aware of multiple logos? In the latter the
> appearance and disappearance of the different logos could give
> another hint on when the show is actually on.

In the US, the rating logos are not persistent (only show up for a few
seconds upon return from commercial break), so are not as useful.

The experimental commflagger will detect any persistent pattern (TV
station, ratings logo, or otherwise). If the ratings logo really is
persistent (and correlates well with commercial/non-commercial), then
it might work better for you. If there are multiple persistent logos,
they will likely be detected, but the experimental commflagger doesn't
handle that scenario very well in terms of deciding what is a
commercial and what isn't (sports banners, news tickers, etc.).

See http://www.mythtv.org/wiki/index.php/User:Rtsai1111 for how to do
diagnostics to see why it's not working for you (if it's not working
for you).


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