Below is a demo of a gtk application I’m writing that uses computer vision to create a musical instrument. The instrument consists of shapes drawn over video captured from a webcam, each shape representing a note. Computer vision algorithms analyze the video to detect an object of our choosing, usually the hand of a player. Moving the detected object into a shape sends a midi note to a software synthesizer, in this case, yoshimi. Audio and midi is processed with using the jack connection toolkit. The video was recorded using ffmpeg libraries. I threw in a spectrogram for fun so I can claim I’ve written code that uses fftw :).
I learn something every time I try to make the GNOME Shell focus-effect extension more obnoxious. This time, I eased multiple properties in one Tween, just like a pro might have done. And, can you say,
Below, find two screen capture demos of making stuff happen with clutter actors and so forth when windows take focus. Believe me, I’ve got more obnoxious ideas for this extension.
- Get and install the v4l2loopback device
- $ sudo modprobe v4l2loopback devices=2
- $ gst-launch-0.10 ximagesrc use-damage=0 ! ffmpegcolorspace ! “video/x-raw-yuv,width=1920,height=1080,framerate=30/1″ ! v4l2sink device=”/dev/video3”
I’ve long admired the work of Fons Adriaensen. For some time, I’ve wanted some sort of level indicator for web audio. So, when I went to implement a meter using the web audio api, I decided I should rip off the wonderful jkmeter for metering jack audio written by Fons. And the below video shows some results. What you see in the screencast is the same signal routed to a meter running in chrome, one in jkmeter, and one in firefox.