Remove same audio sections from audio files - Detect & Trim

Hi Audacity Team! This is my first post :slight_smile:

As a collecter I’ve thousands of audio files which downloaded from podcasting services. All feeds start with a 15 seconds same introduction. That’s very annoying for me so I tried crop all of them.

But all of them are not regular. The voiced presentations are the exactly same but some of them…

  • … are starting at 00:00 or at 00:05 or at any seconds which I don’t know
  • … have not the introduction on startup

I couldn’t determine which seconds should crop/trim

The question: How can we crop/trim the all audio files according to specific audio clip?

In other sayings “detect same part and remove it” ?

Thanks for your support !

PS: My english is a bit poor so I tried to tell my problem with a lot same ways. Sorry for that !

You probably can’t, unless there is a distinct characteristic of the sound to test for. For example, you can test for silence, or for non-silence, or for stereo, or for mono. If there is no distinct characteristic of the sound in measurable terms (such as amplitude or frequency), then you can’t test for it.

Hi Steve! Thanks for reply. Is it so hard? I’m so inexperienced user. I try to tell what what I know even if funny.

There is a plugin which called Noise Removal in Audacity. We can select a few seconds of just noise so Audacity knows what to filter out. Is there any suchlike technical method to completely filter out?

Btw commercially there are great services (Midomi, Shazam…etc) to identify the songs using your voice by singing or humming. They can search and match quickly the same parts. Is there any similar logic which we can use?

Yes it’s pretty hard to do.
Do Midomi or Shazam recognise the intro that you want to remove?

Noise Removal analyses the spectrum of the selection, similar to using “Plot Spectrum” ( and then looks for sections of audio that match the same profile. Theoretically this approach could be taken to solve the problem that you are asking about, but it’s not easy to implement and Audacity does not currently have such a tool.

I’ll move this topic to the “Adding Features” section.

Of course commercial services can recognise easily if they have my audio files on their databases.

Moving the topic is great! That should be developed in the future because there are extensive usage areas like edit unwanted specified section or check availability of the specified section.