[linux-dvb] Re: automatic AD cutting [was "Timing recording"]

[Gerard MAULINO <gmaulino@club-internet.fr>]

Well,

I think that such a tool will be interesting, but, as you said the MPEG 
stream is not a "friendly" format that will easily allow frame recognition.
I suposed that professional solutions are experimental and deal with 
uncompressed video. What need a big amount of disk space.
Anyway, if methods proposed in the docs that sent Alexandre could be 
implemented, a lot of test have to be performed for each of them to 
avoid lostin time in solution that will not be reliable enough.

Gerard

Chris Pitchford wrote:

>There is a much bigger problem with this technology. DVB is not frame by
>frame stream such as capturing an analog signal. The stream is GOP in that
>there is a key frame followed by a series of delta frames (frames that
>collectively only contain differences since the last keyframe)
>
>0        25       50       75      100
>K------->K------->K------->K------->
>   ^Start of programme
>
>if the program starts somewhere after a keyframe then you would like to
>"drop" all the frame prior to the start.. This means that this GOP (group
>of pictures) is not incomplete and must be rebuilt. There aren't many
>tools Ive seen to do this.. certainly none that would on the fly.
>
>Since effectively Mpeg-2 is quantum you can only cut to the nearest group
>of pictures Keyframe. This means, almost certainly, there will be a bit
>before and a bit after the program you want.
>
>Also since so much is analog the process of recognising images becomes
>impressively complex. Twined with the fact you would need to provide test
>data to the recognition software which inself would be particularly
>difficult.
>
>I seem to recall of hearing a project that looked for the, and please
>excuse the fact I forget its official name, but the little flashing black
>and white square in the top left/right corner of the tv picture prior to
>comercial breaks.
>
>It also calculated to time between commercials (the black picture) to
>calculate when a comercial had finished..
>
>Maybe this kind of generic approach would be better suited?
>
>My appologuies if this has all be said before, just my 2p worth
>
>chris
>
>On Fri, 13 Dec 2002, Alexandre CONRAD wrote:
>
>  
>
>>>I don't know what was the outcome of this...
>>>      
>>>
>>Well, I don't care about ads, really, I need to be able to record a
>>program (an everyday episode), and start the recording from the 1st
>>frame and stop it at the last frame.
>>
>>This would work in this case : the program always starts the same way
>>and always ends the same way from an episode to an other. This means
>>that usualy, these programs have a starting and ending generic.
>>
>>The idea here is to record the episode once manually. Extract from the
>>stream the 1st and last frame from the episode's generics
>>
>>FrameA = 1st frame of starting generic
>>FrameZ = Last frame of ending generic
>>
>>Once this is set up, I can record my favourite program everyday (or when
>>ever the program shows, (once a week, every 2 days, only week ends,
>>etc...)) without remembering to record it. My program will know that it
>>have to start recording when it detects FrameA and stop when it detects
>>FrameB.
>>
>>In my particular case, I want to have everything automated for my project.
>>I want to record a program that shows everyday, in the early morning
>>(6oclock, but I'm still sleeping) and then send that recorded to my
>>video server. But I would like to be also able to have it trimed out
>>nice and clean without retouching it manually.
>>
>>Do you get the idea ? And if you have any ideas, your suggestions are open.
>>
>>Regards,
>>
>>--
>>Alexandre CONRAD
>>Research & Development
>>tel : +33 1 30 80 55 00
>>fax : +33 1 30 56 50 20
>>TLV
>>6, rue de la plaine
>>78860 - SAINT NOM LA BRETECHE
>>FRANCE
>>
>>
>>
>>    
>>
>>>
>>>---
>>>Oh yes ! Please Sirs programmers ! Have something done for that ! This
>>>would be so usefull ! You'll be able to record your everyday episodes
>>>whithout thinking about even recording them. Go out on holidays, they
>>>will be there when you come back, all ready to watch and trimed out !
>>>:)))
>>>
>>>There are interesting document here about frame recognition :
>>>
>>>http://www.wisdom.weizmann.ac.il/~armin/AdvVision02/Papers/Lecture12/ActionRecognitionbyShapeMatchingtoKeyFrames.pdf
>>>
>>>
>>>Wave your hands for people willing to work on that, with the open
>>>source spirit ! ;)
>>>
>>>Regards,
>>>
>>>
>>>_________________________________________________________________
>>>MSN Search, le moteur de recherche qui pense comme vous !
>>>http://search.msn.fr/worldwide.asp
>>>
>>>
>>>
>>>      
>>>
>>
>>
>>
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>>    
>>
>
>
>
>  
>




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