Cinder Audio Linux Pi 2/3


I am having difficulties with temperamental audio input on Raspberry Pis. This is what I am observing. I am using the InputAnalyzer sample project shipped with cinder. On the Pi 3, the histogram is displayed for anywhere between 2-10 seconds, but then the histogram freezes. The app is not frozen, clicking produces output in the terminal.

Here are my observations:

  • When the histogram is frozen, the LED on the usb audio device continues to flash, indicating it is in use.
  • USB audio devices work fine with Audacity on the Pi.
  • 3 different USB audio devices were tried, two white Adafruit ones and one Logitech one.
  • Running pavucontrol I can see that the audio is still being monitored, it’s just not getting to cinder.
  • Plugging in other USB devices can sometimes trigger the freeze.
  • 2 different Raspberry Pi 3s were tried (with the same SD card).
  • 1 Raspberry Pi 2 was tried (with the same SD card again). This is far more reliable, with a lower chance of freezing, but freezing is still observed.
  • USB audio device work fine with the InputAnalyzer sample on macOS and Ubuntu 16.4 (VM).
  • I ran sudo apt-get update && sudo apt-get upgrade, then pulled the latest cinder and rebuilt

I followed these to set up audio on the Pis:

USB devices pictured here.