Bluetooth LE Audio Auracast Broadcaster Proxy?

[Hedda]

Describe your idea

Pre-text: Music Assistant server just added support for this experimental Bluetooth LE Audio Auracast Broadcaster via a Bluetooth USB adapter:

• Auracast Provider music-assistant/server#7142

How about the idea of adding a one-way Bluetooth LE Audio Auracast Broadcaster Proxy component to ESPHome as a remote bridge adapter?

• https://www.bluetooth.com/auracast/

  • https://www.bluetooth.com/learn-about-bluetooth/feature-enhancements/le-audio/

For reference, ESPHome already have a Bluetooth Proxy concept to proxy BLE devices to Home Assistant which in practice acts as a remote Bluetooth bridge adapter for Home Assistant's Bluetooth integration. Which is kind of similar concept but really the reverse:

• https://esphome.io/components/bluetooth_proxy/

  • https://esphome.io/components/esp32_ble/

I propose making a Bluetooth LE Audio Auracast Broadcasting component to ESPHome which would recieve an audio stream (for example from Home Assistant or Music Assistant via Sendspin) and then it would turn that into a nto an Auracast broadcast (BLE Audio broadcast) similar to this ESP32-S31 Auracast Transmitter project (from malarisch) found here:

• https://github.com/malarisch/esp32s31-auracast-transmitter

That would allow the audio feed to go straight into a Bluetooth LE Audio receiver (such as example hearing-aids and wireless headphones or receivers that support Bluetooth LE 5.4):

• https://www.bluetooth.com/auracast/find-a-product/

The essense of this idea is to add support for remote Auracast Proxy devices (a.k.a. a Bluetooth LE Audio bridge device) based on "ESP32-S31" for broadcasting audio to Auracast as output (as an alternative to using a Bluetooth USB adapter in Music Assistant or Home Assistant), and this should be technically possible in theory with the relativly new ESP32-S31 (or ESP32-H4) microcontrollers because those have has support for Bluetooth LE Audio (BLE 5.4 LE Audio as well as BT Classic A2DP).

As such hardware and upstream library requirements are the relativly newer ESP32-S31 (or ESP32-H4) microcontrollers which are the only ESP32 chips that support Bluetooth 5.4 LE. And as far as I can tell Espressif has also already added Bluetooth LE Audio support to its upstream libraries (esp_bt_audio and esp-gmf):

• https://esp32-s31.espressif.com/en/official-projects/5

• https://docs.espressif.com/projects/esp-idf/en/latest/esp32s31/api-guides/esp-ble-audio/ble-audio-introduction.html

• https://docs.espressif.com/projects/esp-adf/en/latest/solution-center/bluetooth-audio.html

• https://components.espressif.com/components/espressif/esp_bt_audio/versions/0.8.2/readme

• https://github.com/espressif/esp-gmf

• https://github.com/EchoLink-Speaker/esp32-s31

• https://www.lst-iot.com/esp32-s31-solutions-for-audio-devices/

Be aware that this is indirectly related to mbrudka's work on getting Bluetooth Audio support added to the esp32_ble component:

• [esp32_ble] Add optional Bluetooth Classic controller mode esphome#21408

• [a2dp_source] Add single-receiver Bluetooth Classic speaker output esphome#21782

• [a2dp_source] Add Classic receiver discovery, pairing, and switching esphome#21783

Tip! If this sounds interesting then a tip if to search for "ESP32-S31-Function-CoreBoard-1" (official development board from Espressif) as that is designed for early-adopter prototyping and it at least looks to be available from a few third-party resellers:

• https://docs.espressif.com/projects/esp-dev-kits/en/latest/esp32s31/esp32-s31-function-coreboard-1/user_guide.html

  • https://www.google.com/search?q=%22ESP32-S31-Function-CoreBoard-1%22

Why is this exciting?

Bluetooth LE Audio and Auracast is still very new and not yet wide-spread, but it is the future of Bluetooth Audio.

Auracast in particular is cool because it uses broadcasting without pairing, so from a end-user perspective it works kind of similar to AM/FM radio, meaning that users only need to tune on to that as an open broadcast (and do not need to authenticate anything).

This eaables an audio source to be broadcasted as one or more audio streams to an unlimited number of Auracast audio sink devices. Broadcast audio opens significant new opportunities for innovation, including the enablement of a new Bluetooth LE Audio capability,

Potential use cases

Broadcast any audio stream (like announcements and/or music) via Auracast from ESPHome BLE Audio proxies to Auracast recievers:

• https://www.bluetooth.com/auracast/find-a-product/

Primary use case is today:

• Hearing-aids that support Bluetooth LE 5.4 with Auracast recieving.

• Wireless headphones or other type of wireless receivers that support Bluetooth LE 5.4 with Auracast recieving.

Anything else?

For proof-of-concept see malarisch's esp32s31-auracast-transmitter project:

• https://github.com/malarisch/esp32s31-auracast-transmitter

Ping Yago Fontoura do Rosário (@Yagoor) FYI for music-assistant/server#7142