Read Incoming Bluetooth Audio On Pi With Python

Question

this is my first post on here! I am trying to make my raspberry pi 3 a bluetooth speaker which synchronizes beat of the music being played from a phone to an LED light strip. For the LED light synchronization I have made a python script that uses PyAudio and AudioOp packages to do analysis on the audio input stream.

Right now, I am able to play music to the 3.5mm headphone jack of the raspberry pi 3 from my phone over bluetooth with no problem. However, my issue is creating an input source for PyAudio to recognize and read the incoming audio. I read into creating audio loop backs and virtual audio cables but I am a bit lost on the subject and I am not sure that is the right approach. Below are the established audio playback and capture devices when the raspberry pi boots up without any modification on my part.

**** List of PLAYBACK Hardware Devices ****
card 0: ALSA [bcm2835 ALSA], device 0: bcm2835 ALSA [bcm2835 ALSA]
  Subdevices: 6/7
  Subdevice #0: subdevice #0
  Subdevice #1: subdevice #1
  Subdevice #2: subdevice #2
  Subdevice #3: subdevice #3
  Subdevice #4: subdevice #4
  Subdevice #5: subdevice #5
  Subdevice #6: subdevice #6
card 0: ALSA [bcm2835 ALSA], device 1: bcm2835 IEC958/HDMI [bcm2835 IEC958/HDMI]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: ALSA [bcm2835 ALSA], device 2: bcm2835 IEC958/HDMI1 [bcm2835 IEC958/HDMI1]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

**** List of CAPTURE Hardware Devices ****

I appreciate any guidance you may have for me to solve this problem.

Answer 1

About half way down on the following page it says:

https://github.com/Arkq/bluez-alsa

BlueALSA also allows to capture audio from the connected Bluetooth device. To do so, one has to use the capture PCM device, e.g.:

$ arecord -D bluealsa capture.wav

Using this feature, it is possible to create Bluetooth-powered speaker. It is required to forward audio signal from the BlueALSA capture PCM to some other playback PCM

Does that help?