Going from audio to waveform image and back to audio
In my last post I showed how I found a great audio to waveform plugin and I also created a .PNG image with the waveform so I could save it.
But what if I wanted to read the waveform and create audio from it, i.e. convert it back.
The sampling frequency / resolution of the waveform plays a important role of course. In my last post the resolution was 100 pixels / second which is way too low (CD quality would be 44100 px/s).
So, I had to go with that.
This is my original recording:
The first step is to create an image so I created a new version of my last post but with 4000 px/s. Here’s the image (9002 x 128 px).
The next step was to find an app that can read this and convert it to audio. This was more difficult that I thought but via mediapreservation.wordpress.com I found a program named ImageToSound.
This was an old app (and for Windows) so I downloaded WinXP from modern.ie and installed it.
ImageToSound takes .bmp-files so I had to convert my .png file. Easy to do in Pixelmator or Photoshop.
Time to import the bmp to ImageToSound and see if I got anything.
It’s important to choose 4000 as the sample rate since that’s what I used when I created the pic.
Alright, let’s listen to it.
Now you can print any sound to paper and save it for the future generations! :)