Detecting audio loops

[manavortex]

Hello there, 
I have a preexisting audio file that may contain loops. I'd like to know for certain. How can I detect repeating audio across a file?

Can I "split" the file at the x-axis to look at the channels separately? 

(The answer to the question in the picture is most likely "no," since it's just an example. I'd just like to know if Audition can help me finding out in any way, and if so, what I have to do for that.)

[SteveG_AudioMasters_]

I don't think you really understand how sound waveforms work, otherwise you wouldn't have posted a waveform with a positive-going section and a negative-going one highlighted and assumed that this could ever be a loop. That waveform you've shown is only of a single channel - there aren't two channels there at all. And a loop would have to be a repeat of a whole section of both the positive and negative sections of a waveform.

If you want to detect any examples of a loop, then first you will have to identify one. Then you will have to select the whole of it and teach it to Audition as a Sound Model, although this isn't going to allow you to pick up a large sample. At this point the Sound Removal tool might identify identical parts of the waveform - but it's really not that good at large, complicated sections, as it's really intended for small sounds that you might want to remove.

If I was going to identify anything that was repeated, I'd use my ears and then cut and paste the bits that I thought might be into a single file - they'd be relatively easy to detect then, and if there's any real doubt there's at least one more trick you can do which involves inverting one copy and pasting it over the other - if everything disappears, it's a direct copy.

But the whole process has to start with you identifying what you're looking for - no software will do this for you.

[manavortex]

Hey, 

> I don't think you really understand how sound waveforms work, otherwise...

Correct, I don't really understand how any of this works. 🙂 It's why I've been asking.

> the whole process has to start with you identifying what you're looking for.

I'm looking for "any subset of the given audio data with a length of >5s that exists more than once in the sound data". 

> no software will do this for you 

So I understand you correctly that there's no way to have Audition run pattern matching on the frequency graph or anything? I could possibly figure out how to export the curve and parse the graph, but given that this is an Adobe product I figured it might be worth a shot.

[SteveG_AudioMasters_ · Accepted solution]

No, you really can't do it. This is audio we're talking about, and you have to listen to it to identify loops. You could have two identical sections of material that appeared on a spectrograph, but if there was an underlying change in the background sound behind them, for instance, or anything else mixed with them, then no auto-detecting software is ever going to isolate them. That's what you use your ears for.

[manavortex]

Thank you for telling me. That's... not what I'd have expected, especially since it's the same audio file and the graph looks unique enough. Guess we know why I'm an engineer and not an Audio Master now. 
At least it'll be out here for Google if the next person needs it, and I can stop trying to find the setting 🙂 

[animationlife]

Audio Is Complicated, Steve Is a Audio Master, and I always take his advice.

Good Luck.

[SteveG_AudioMasters_]

AudioMasters was the resurrected and renamed version of the old Syntrillium forum that closed when Adobe bought the company and a lot of its staff. We kept the forum running independently for - I can't remember, but about 10-12 years until its usefulness subsided to the point where it wasn't worth keeping it running. So the AudioMasters reference is only there for anybody transitioning from the old forum to this one, so that they recognise that the SteveG on this forum is in fact the same one as the one on the old forum. Unfortunately I can't now lose the AudioMasters tag because there's already another SteveG on the Adobe forums, apparently.

So it's not quite what you think!

[animationlife]

 Dear Steve G AudioMasters.

I like this name. The Most important thing is your Advice regarding Audition, and you been in this business for a long time, Therefore I respect your Advice. As I said before, Sound Is Complicated and Tricky.

Thanks Again.