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Content Identification in Digital TV Signal

Posted: Tue Sep 02, 2014 3:33 am
by adam_sash
Is it possible to identify different elements of a digital television signal? Example being the television channel watermark, actual television program, beginning and ending of television commercial windows...

Interested to see if signal identification is possible without having to actually watch the show...

Re: Content Identification in Digital TV Signal

Posted: Tue Sep 02, 2014 5:30 am
by w9wi
What exactly do you mean by "signal identification"? -- what are you trying to identify?

Re: Content Identification in Digital TV Signal

Posted: Tue Sep 02, 2014 6:29 am
by adam_sash
different elements or triggers (if they exist) in the digital signal. A simple one would be the start and end of a TV commercial. Trying to work out how protected this information is in the source code of the television signal..

Re: Content Identification in Digital TV Signal

Posted: Tue Sep 02, 2014 8:26 am
by Deep Thought
Sounds like someone is trying to figure out an automagic commercial zapper...

Re: Content Identification in Digital TV Signal

Posted: Tue Sep 02, 2014 4:23 pm
by NECRAT
Deep Thought wrote:Sounds like someone is trying to figure out an automagic commercial zapper...
And it won't work. The information regarding the breaks sits on the server side. The server video outputs, while going through many phases, ends up being encoded so that most information ends up just a continuous stream. The only information you *may* get is AFD data, but that can change from spot to spot, and program to spot. Audio won't give you much either.

Why specifically are you looking for this information?

Re: Content Identification in Digital TV Signal

Posted: Thu Sep 04, 2014 12:02 pm
by PID_Stop
adam_sash wrote:Is it possible to identify different elements of a digital television signal? Example being the television channel watermark, actual television program, beginning and ending of television commercial windows...

Interested to see if signal identification is possible without having to actually watch the show...
What you are assuming to be distinctly different elements -- branding logos, program content, commercials -- are not in fact separate elements by the time you see them, but are all part of the same program stream. To use an analogy, consider the audio channels: that's a complete mix of vocals, effects, and music... you can't break it back down into individual voices, drums, guitars, horns, and so on.

At the television station level, the video often does contain special signalling information -- metadata -- to perform certain functions like inserting logos or starting station breaks... but I don't think most of it survives the encoding process to feed the transmitter, except for the automatic format descriptor (AFD).

-- Jeff

Re: Content Identification in Digital TV Signal

Posted: Thu Sep 04, 2014 8:18 pm
by Baylink
Adam: you can at least make a slash at it, but it will involve decoding the MPEG TS/PS, and then doing heuristic analysis of the images you get.

It won't be easy...