Bluetooth Audio (A2DP Source and Sink)

The PicoW can be used as a Bluetooth Audio sink or source with the BluetoothAudio class. Operation is generally handled “automatically” in the background so while the audio is playing or streaming the main application can perform other operations (like displaying playback info, polling buttons for controls, etc.)

#include <BluetoothAudio.h>
...

Note about CPU usage: Bluetooth SBC audio is a compressed format. That means that it takes non-trivial amounts of CPU to compress on send, or decompress on receive. Transmitting precompressed audio from, say, MP3 or AAC, requires first decompressing the source file into raw PCM and then re-compressing them in the SBC format. You may want to consider overclocking in this case to avoid underflow.

A2DPSink

This class implements slave sink-mode operation with player control (play, pause, etc.) and can play the received and decoded SBC audio to PWMAudio, I2S, or a user-created BluetoothAudioConsumer` class.

The A2DPSink.ino example demonstrates turning a PicoW into a Bluetooth headset with PWMAudio.

A2DPSource

This class implements a master source-mode SBC Bluetooth A2DP audio connection which transmits audio using the standard Stream interface (like I2S or PWMAudio. The main application connects to a Bluetooth speaker and then writes samples into a buffer that’s automatically transmitted behind the scenes.

The A2DPSource.ino example shows how to connect to a Bluetooth speaker, transmit data, and respond to commands from the speaker.