Antonio Roberts (hellocatfood) and Maria Witek (mxwx) use Troop + Tidal Cycles to collaboratively live code experimental techno. Both relatively new to live coding music, they are working together to develop a high energy aesthetic that is both heavy and groovy.
One of my overall goals is to find a way to databend live video. I’m sure there’s a way to do it with Processing and PureData but I’m not yet proficient in those programs so they’re out of the question for now. In the meantime I thought to try and hack the Echobender script to databend my webcam images.
>tonyg provides a great tutorial on how to convert live webcam images into audio, which I’ve used as a starting point for my hack.
The process for making it works is as follows:
- Images from the webcam are saved to the computer
- These are converted to a .bmp file then renamed to a .raw file
- Sox applies an audio effect to the .raw file
- The .raw file is converted back to a .bmp then to a .jpg
- The updated webcam image is displayed to a window and updated once every second
Sound overly complicated? It probably is. Like the Echobender script you’ll need ImageMagick and Sox but we’ll also be using Webcam, which you can install via
sudo apt-get install webcam
If you haven’t already, create a file called
.webcamrc in your home directory (/home/yourusername) and enter this text into it:
[grab] delay = 0 text = “” [ftp] local = 1 tmp = uploading.jpg file = webcam.jpg dir = . debug = 1
Now create a file called grabframe, place it in your home directory and fill it with this:
#!/bin/sh while [ ! -e webcam.jpg ]; do sleep 0.1; done convert webcam.jpg frame.bmp cp frame.bmp frame.raw sox -r 482170 -e u-law frame.raw frame2.raw echos 0.8 0.9 5000 0.3 1800 0.25 convert -size 640x240 -depth 4 rgb:frame2.raw -trim -flip -flop output.bmp convert output-0.bmp output.jpg
To start things running, open up three terminal instances:
- In shell number one, run
- In shell number two, run “while true; do
./grabframe ; done.
- In shell number three, run
display -update 1 output.jpg
I know it’s quite slow, but I haven’t yet found a way to update faster and it’ll still be restricted by the time it takes Sox/ImageMagick to perform their conversions.