[mythtv-users] commercial flagging only some recordings

[Mike Perkins]

Matt Doran wrote:
> Robert Tsai wrote:
>> On Wed, May 23, 2007 at 08:52:22AM -0400, Michael T. Dean wrote:
>>   
>>> On 05/23/2007 04:36 AM, Leigh Porter wrote:
>>>     
>>>> However.. I am in the UK and I have noticed that commflag does not
>>>> seem to work too well on UK channels, is this the case?
>>>>       
>>> Robert Tsai has been doing some work--in what free time he has--on
>>> improving the flagger, especially for those outside the US.  And,
>>> IIRC, he's in the UK, so once it's incorporated into Myth...
>>>     
>> The code is already accessible in MythTV as the "Experimental" option
>> in the choice of commflaggers.
>>
>> I live in the US.
>>
>> I find that it works better than the "all" flagger, for me, for my OTA
>> HD recordings.
>>
>> I can't say if it represents a regression from the "all" flagger for
>> other kinds of recordings (cable TV, non-US, etc.). But if the "all"
>> one doesn't work for you, then you may as well give "experimental" a
>> shot.
>>
>> If you want to know why the "experimental" flagger isn't doing a good
>> job, this page will describe how you can get a graphical depiction of
>> what it thinks is going on:
>>
>> 	http://www.mythtv.org/wiki/index.php/User:Rtsai1111
>>
>> It is heavily biased towards logo detection (since that is a good
>> indicator for OTA HD broadcasts, probably not as reliable for cable
>> TV). If logo presence is not a good indicator in the UK, then this
>> will probably not work so well for you.
>>
>>   
> Hi Rob,
> 
> I'm in Australia, and I've found the default commflagger to be pretty 
> hit and miss.  At a guess it probably gets less than 30-50% of 
> commercials, but some channels are better than others.
> 
> All the stations in Aus make use of station logos/watermarks, so I'm 
> going to give your experimental flagger a try.  I'm not sure what logos 
> are like in other countries... but here in Aus they are quite 
> transparent, and appear in different positions on each channel.  Most 
> are in the bottom right, but at least one channel is in the upper right.
> 
> I'm curious to know how this differs from the default flagger, which 
> also does logo detection.  Is it described anywhere?  Can you give us a 
> bit of an overview?
> 
> Under what circumstances does the experimental flagger outperform the 
> default one?
> 
> Thanks,
> Matt
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> 
On cable, in the UK, at least one channel, Sci-Fi, keeps the logo on the 
screen the whole time, adverts or no :(  So that particular method won't 
work. Neither do most channels that I have investigated (not a vast 
number, to be sure, but a selection) have 'blank frames' such as you 
have described for the North American market, delimiting the adverts.

What we do get a lot of are static frames or short sequences (~5 sec) 
which show the channel, program name and optionally the sponsor, shown 
at the beginning and end of each program segment. I doubt that these 
could be picked up automatically, but if one hit 'E' and identified one 
then the rest could be picked out of the stream quite readily, thus 
delimiting the breaks.

Unfortunately, of course, this does not apply to all channels. Probably 
a result of having such a wide variety of programming available. But it 
does make the break detection somewhat difficult. It's a bit like the 
spam race: they think of a new method to bypass the filters, we refine 
the filters.

Mike Perkins