3 ms·

It seems not too terribly difficult to subtract the copyright audio from the videos. Step 1: Identify the audio being played via Shazaam or similar algorithms.

by mabbo 5y ago

It seems not too terribly difficult to subtract the copyright audio from the videos. Step 1: Identify the audio being played via Shazaam or similar algorithms. Step 2: Find the overlap between the copyright song and the video's audio, because it won't be a perfect match. Step 3: Subtract that audio from the video's audio. It wouldn't be perfect and I'll bet it creates a lot of weirdness if, say, the office sings your Miranda Rights to the same tune as the song, but overall it would work and it would help stamp out this sort of problem. You could make a website that does this for uploaded videos.

jstanley 5y ago
I'm actually really curious to find out whether this would work. It sounds quite easy to test, I wonder if anyone has already done it? My feeling is that it wouldn't work very well at all, because of things like the Doppler effect shifting the sound as you move the mic closer to or further from the source, and also the sampling on the microphone might be out of phase with the original recording. But the more I think about it, the more I think those might only be minor problems and it would actually work well? EDIT: And the frequency response of the speaker & microphone are almost certainly non-uniform. EDIT2: From a quick test, it doesn't even slightly work. Here's what I did: 1. Find a song on youtube 2. Save the song to an MP3 with https://www.bestmp3converter.com https://www.bestmp3converter.com (or use youtube-dl - bestmp3converter.com probably uses youtube-dl) 3. Play the song on YouTube and record it using my phone 4. Load the MP3 and the recording from my phone in Audacity as 2 separate tracks 5. Amplify the phone recording until it looks like it matches the MP3 (Effect -> Amplify) 6. Delete some samples at the start of the phone recording so that the 2 tracks visually line up 7. Invert one of the tracks (Effect -> Invert) 8. Add the 2 tracks together (select both tracks, then Tracks -> Mix -> Mix and Render to New Track) 9. Mute the 2 original tracks and listen to the mixed result - it still sounds exactly like the song. It's not even slightly muffled. It sounds the same even if you don't invert one of the tracks. I think this is just much too far away from lining up sample-for-sample to be close to working.
- JohnFen 5y ago
  In a job I had a couple of decades ago, I did work very much like this (not with music, but along the same lines). This certainly can be done, but your method isn't the way to do it. There are two primary methods of accomplishing this. The fast and dirty method is to employ a notch filter to exclude all frequencies outside of those used by the human speaking voice (which, fortunately, is a rather narrow frequency range). The second is to perform some fancy mathemetics to be more selective about what you're filtering out and when. There are a number of different approaches to this, but they typically involve autocorrelations or crosscorrelations. Both methods will cause a degradation of the audio you want to keep (the quick and dirty method will cause more degradation than the sophisticated methods). But the Q&D is often good enough, and is often used by karaoke machines and the like. Simply trying to subtract out the known signal (as you were doing) is technically plausible -- and is done for certain types of signals -- but is very hard to do effectively. There are too many environmental effects that will distort the signal and make naive subtraction ineffective.
LinuxBender 5y ago
If that doesn't work, another option may be to link the video to the publisher of the song and provide the city/department name. I am not a lawyer, but hopefully one will chime in that is an expert on media content laws. Some publishers take public broadcasting of their works very seriously. Public broadcasting in this case is not just Youtube, but also the police officer playing for the audience in a public setting. Restaurant and bar owners are familiar with this. They are only allowed to play content for their customers that has been licensed to them and license does not mean a personal spotify account. There are fines for non-compliance. [1] This is not the same as blasting music in your car in case anyone draws the comparison. The officer is playing the music for their audience / customers with the intent of it being on Youtube. In my opinion it should be easy to prove intent in this case. [1] - https://pos.toasttab.com/blog/on-the-line/a-crash-course-in-restaurant-music-licensing-laws https://pos.toasttab.com/blog/on-the-line/a-crash-course-in-...

by mabbo 5y ago

jstanley 5y ago

I'm actually really curious to find out whether this would work. It sounds quite easy to test, I wonder if anyone has already done it? My feeling is that it wouldn't work very well at all, because of things like the Doppler effect shifting the sound as you move the mic closer to or further from the source, and also the sampling on the microphone might be out of phase with the original recording. But the more I think about it, the more I think those might only be minor problems and it would actually work well? EDIT: And the frequency response of the speaker & microphone are almost certainly non-uniform. EDIT2: From a quick test, it doesn't even slightly work. Here's what I did: 1. Find a song on youtube 2. Save the song to an MP3 with https://www.bestmp3converter.com https://www.bestmp3converter.com (or use youtube-dl - bestmp3converter.com probably uses youtube-dl) 3. Play the song on YouTube and record it using my phone 4. Load the MP3 and the recording from my phone in Audacity as 2 separate tracks 5. Amplify the phone recording until it looks like it matches the MP3 (Effect -> Amplify) 6. Delete some samples at the start of the phone recording so that the 2 tracks visually line up 7. Invert one of the tracks (Effect -> Invert) 8. Add the 2 tracks together (select both tracks, then Tracks -> Mix -> Mix and Render to New Track) 9. Mute the 2 original tracks and listen to the mixed result - it still sounds exactly like the song. It's not even slightly muffled. It sounds the same even if you don't invert one of the tracks. I think this is just much too far away from lining up sample-for-sample to be close to working.

JohnFen 5y ago
In a job I had a couple of decades ago, I did work very much like this (not with music, but along the same lines). This certainly can be done, but your method isn't the way to do it. There are two primary methods of accomplishing this. The fast and dirty method is to employ a notch filter to exclude all frequencies outside of those used by the human speaking voice (which, fortunately, is a rather narrow frequency range). The second is to perform some fancy mathemetics to be more selective about what you're filtering out and when. There are a number of different approaches to this, but they typically involve autocorrelations or crosscorrelations. Both methods will cause a degradation of the audio you want to keep (the quick and dirty method will cause more degradation than the sophisticated methods). But the Q&D is often good enough, and is often used by karaoke machines and the like. Simply trying to subtract out the known signal (as you were doing) is technically plausible -- and is done for certain types of signals -- but is very hard to do effectively. There are too many environmental effects that will distort the signal and make naive subtraction ineffective.

LinuxBender 5y ago

If that doesn't work, another option may be to link the video to the publisher of the song and provide the city/department name. I am not a lawyer, but hopefully one will chime in that is an expert on media content laws. Some publishers take public broadcasting of their works very seriously. Public broadcasting in this case is not just Youtube, but also the police officer playing for the audience in a public setting. Restaurant and bar owners are familiar with this. They are only allowed to play content for their customers that has been licensed to them and license does not mean a personal spotify account. There are fines for non-compliance. [1] This is not the same as blasting music in your car in case anyone draws the comparison. The officer is playing the music for their audience / customers with the intent of it being on Youtube. In my opinion it should be easy to prove intent in this case. [1] - https://pos.toasttab.com/blog/on-the-line/a-crash-course-in-restaurant-music-licensing-laws https://pos.toasttab.com/blog/on-the-line/a-crash-course-in-...