Folks, I want to be able to detect commercial breaks :) So it seems that (in the Netherlands at least) on TV, the sound of commercials is broadcasted through some massive compressor-limiter while "regular" broadcasts such as movies and newsbreaks have "normal" sound. I think someone has already come up with this so I'd like to know how to be able to detect this. I've been thinking/hypothesizing about the best way to handle this. I tried to measure the difference in energy levels (on average) of the sound. This did not have the preferred result :) Maybe there are some options in the frequency domain? I know there were VCR's in the old days that detected the blanks (black screens) at the beginnings and ends of commercials, but that mechanism doesn't work anymore... they don't put in blanks anymore! With digital broadcasting one could detect a bitrate change (commercials are usually broadcasted in higher bitrates). Although this would be difficult with VBR broadcasts. So, DSP gurus... I've had some good results with you in the past. Can you help me again this time? :-) Cheers, Rob Vermeulen rvermeulen a t arbor-audio d o t com
Compressor-limiter detection
Started by ●October 7, 2004
Reply by ●October 7, 20042004-10-07
Are you limited to looking at the audio portion of the broadcast, or can you look at the video as well? FYI, I have a VCR that performs this feature, and it still works fine (probably 90-95% accuracy) with today's US broadcasts. It uses an "off-line" process, that is, after it finishes recording, it goes back and scans the recorded segment for commercials and marks this information on tape. Then on playback, it skips those sections. It is a nice because it is a "non-destructive" system--even if it messes up, you don't lose any program material. I'm guessing that for a robust system, you will probably need to employ multiple methods--looking at the audio, the video, doing some timing assuming that commercials generally come in 30-second intervals, etc.. I don't think any one method will be fool-proof over the wide range of TV content. "Rob Vermeulen" <rpvermeulen@tiscali-antispam-.nl> wrote in message news:4165862c$0$44101$5fc3050@dreader2.news.tiscali.nl...> Folks, > > I want to be able to detect commercial breaks :) > So it seems that (in the Netherlands at least) on TV, the sound of > commercials is broadcasted through some massive compressor-limiter while > "regular" broadcasts such as movies and newsbreaks have "normal" sound. > I think someone has already come up with this so I'd like to know how to be > able to detect this. > > I've been thinking/hypothesizing about the best way to handle this. I tried > to measure the difference in energy levels (on average) of the sound. This > did not have the preferred result :) > Maybe there are some options in the frequency domain? > > I know there were VCR's in the old days that detected the blanks (black > screens) at the beginnings and ends of commercials, but that mechanism > doesn't work anymore... they don't put in blanks anymore! > With digital broadcasting one could detect a bitrate change (commercials are > usually broadcasted in higher bitrates). Although this would be difficult > with VBR broadcasts. > > So, DSP gurus... I've had some good results with you in the past. Can you > help me again this time? :-) > > Cheers, > > Rob Vermeulen > rvermeulen a t arbor-audio d o t com > >
Reply by ●October 7, 20042004-10-07
Jon,> It is a nice because it is a > "non-destructive" system--even if it messes up, you don't lose any program > material.I was already thinking of doing it that way. Record it all and do a check afterwards, or at the same time, depending on the realtime aspect of the detection. Then I'd save the metadata alongside the AV content and let the player decide what to play back and what not.> Are you limited to looking at the audio portion of the broadcast, or canyou> look at the video as well?Sure I can look at the video as well, I just did not have any thoughts of what kind of detection I could possibly do on it. Do you know what your VCR does? Come to think of it... all stations place their logos on the topleft or topright of the screen, except on commercial breaks. Maybe I could do some detection on overlayed images. hmmm.... Enough thoughts though. but help's appreciated! Cheers, Rob "Jon Harris" <goldentully@hotmail.com> wrote in message news:2slfc7F1mo7ogU1@uni-berlin.de...> Are you limited to looking at the audio portion of the broadcast, or canyou> look at the video as well? FYI, I have a VCR that performs this feature,and it> still works fine (probably 90-95% accuracy) with today's US broadcasts.It uses> an "off-line" process, that is, after it finishes recording, it goes backand> scans the recorded segment for commercials and marks this information ontape.> Then on playback, it skips those sections. It is a nice because it is a > "non-destructive" system--even if it messes up, you don't lose any program > material. > > I'm guessing that for a robust system, you will probably need to employmultiple> methods--looking at the audio, the video, doing some timing assuming that > commercials generally come in 30-second intervals, etc.. I don't thinkany one> method will be fool-proof over the wide range of TV content. > > "Rob Vermeulen" <rpvermeulen@tiscali-antispam-.nl> wrote in message > news:4165862c$0$44101$5fc3050@dreader2.news.tiscali.nl... > > Folks, > > > > I want to be able to detect commercial breaks :) > > So it seems that (in the Netherlands at least) on TV, the sound of > > commercials is broadcasted through some massive compressor-limiter while > > "regular" broadcasts such as movies and newsbreaks have "normal" sound. > > I think someone has already come up with this so I'd like to know how tobe> > able to detect this. > > > > I've been thinking/hypothesizing about the best way to handle this. Itried> > to measure the difference in energy levels (on average) of the sound.This> > did not have the preferred result :) > > Maybe there are some options in the frequency domain? > > > > I know there were VCR's in the old days that detected the blanks (black > > screens) at the beginnings and ends of commercials, but that mechanism > > doesn't work anymore... they don't put in blanks anymore! > > With digital broadcasting one could detect a bitrate change (commercialsare> > usually broadcasted in higher bitrates). Although this would bedifficult> > with VBR broadcasts. > > > > So, DSP gurus... I've had some good results with you in the past. Canyou> > help me again this time? :-) > > > > Cheers, > > > > Rob Vermeulen > > rvermeulen a t arbor-audio d o t com > > > > > >
Reply by ●October 7, 20042004-10-07
"Rob Vermeulen" <rpvermeulen@tiscali-antispam-.nl> wrote in message news:41658d90$0$44064$5fc3050@dreader2.news.tiscali.nl...> Jon, > > > It is a nice because it is a > > "non-destructive" system--even if it messes up, you don't lose any program > > material. > > Sure I can look at the video as well, I just did not have any thoughts of > what kind of detection I could possibly do on it. > Do you know what your VCR does?I don't know for sure, but I'm guessing it is based on detecting video and/or audio blanks.> Come to think of it... all stations place their logos on the topleft or > topright of the screen, except on commercial breaks. Maybe I could do some > detection on overlayed images. hmmm....That might be a good option for modern broadcasts where this is common.> Enough thoughts though. but help's appreciated! > > Cheers, > > Rob
Reply by ●October 7, 20042004-10-07
Rob Vermeulen wrote: ...> Come to think of it... all stations place their logos on the topleft or > topright of the screen, except on commercial breaks. Maybe I could do some > detection on overlayed images. hmmm....... Often the bottom right, too. Jerry -- When a discovery is new, people say, "It isn't true." When it becomes demonstrably true, they say, "It isn't useful." Later, when its utility is evident, they say, "So what? It's old." a paraphrase of William James ���������������������������������������������������������������������
Reply by ●October 8, 20042004-10-08
Reply by ●October 8, 20042004-10-08