Strip one audio stream from a combined stream

Audacity 3 Help Forum Windows
1

Hi all! Apologies for the slightly vague subject line. :slight_smile:

Basically, as part of forensics coursework I have created an audio stream of an image using Coagula.

I then mixed this with audacity to produce a secondary , combined audio stream having changed the rate of the image stream so when they are listened to together the image is not perceptible. ( Hope this is making sense!)

So, I now have the original audio stream which is a song. And the modified stream of the image ā€˜noiseā€™ and the song.

Iā€™m looking for a way to provide both stream to Audacity and subtract the original stream from modified leaving the image noise.

So, (Modified Stream - Original Song) = Image Noise which I can then run through something like Sonic Visualiser to see the image again.

Is this possible in Audacity at all?

2

Are you doing all this work in MP3?
Koz

3

Are you using ā€œImageā€ in the Exact Copy of a Disk Drive sense, or ā€œSelfie At The Beachā€ sense? Audacity has no image processing abilities.

Koz

4

Hi Koz, thanks for the reply.

Yes I meant image as in ā€˜Selfie at the beachā€™ kind, :slight_smile:

Iā€™ve added a png to illustrate.

Coagula did the image to audio conversion so I have a nice hiss and crackle track of noise, the black and white lined image is what Sonic Visualiser spits out after some playing with the spectrograph properties.

I then stuck this track in Audacity along with a generic mp3 (both mp3 btw) and ramped up the bitrate of image.mp3 to conceal it, then rendered both as a new track.

So I need to know, if itā€™s possible, given both halves of combined track can we split it back down in Audacity?

Cheers for your time. :wink:
Coagula.jpg