| .. _bluetooth_le_audio_arch: |
| |
| LE Audio Stack |
| ############## |
| |
| .. figure:: img/ble_audio_arch.svg |
| :align: center |
| :alt: Bluetooth Audio Architecture |
| |
| Bluetooth Audio Architecture |
| |
| Generic Audio Framework (GAF) |
| ***************************** |
| The Generic Audio Framework (GAF) is considered the middleware of the Bluetooth |
| LE Audio architecture. The GAF contains the profiles and services that allows |
| higher layer applications and profiles to set up streams, change volume, control |
| media and telephony and more. The GAF builds on GATT, GAP and isochronous |
| channels (ISO). |
| |
| GAF uses GAP to connect, advertise and synchronize to other devices. |
| GAF uses GATT to configure streams, associate streams with content |
| (e.g. media or telephony), control volume and more. |
| GAF uses ISO for the audio streams themselves, both as unicast (connected) |
| audio streams or broadcast (unconnected) audio streams. |
| |
| GAF mandates the use of the LC3 codec, but also supports other codecs. |
| |
| .. figure:: img/gaf.svg |
| :align: center |
| :alt: Generic Audio Framework |
| |
| Generic Audio Framework |
| |
| The top-level profiles TMAP and HAP are not part of the GAF, but rather provide |
| top-level requirements for how to use the GAF. |
| |
| GAF has been implemented in Zephyr with the following structure. |
| |
| .. figure:: img/zephyr_gaf.svg |
| :align: center |
| :alt: Generic Audio Framework |
| |
| Zephyr Generic Audio Framework |
| |
| Bluetooth Audio Stack Status |
| ============================ |
| |
| The following table shows the current status and support of the profiles in the |
| Bluetooth Audio Stack. |
| |
| .. table:: Bluetooth Audio Profile status |
| :widths: auto |
| |
| +--------+-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | Module | Role | Version | Added in Release | Status | Remaining | |
| +========+===============================+=========+==================+=======================+==================================================+ |
| | VCP | Volume Renderer | 1.0 | 2.6 | - Feature complete | - Sample Application | |
| | | | | | - Shell Module | | |
| | | | | | - BSIM test | | |
| | +-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | | Volume Controller | 1.0 | 2.6 | - Feature complete | - Sample Application | |
| | | | | | - Shell Module | | |
| | | | | | - BSIM test | | |
| +--------+-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | MICP | Microphone Device | 1.0 | 2.7 | - Feature complete | - Sample Application | |
| | | | | | - Shell Module | | |
| | | | | | - BSIM test | | |
| | +-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | | Microphone Controller | 1.0 | 2.7 | - Feature complete | - Sample Application | |
| | | | | | - Shell Module | | |
| | | | | | - BSIM test | | |
| +--------+-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | CSIP | Set Member | 1.0.1 | 3.0 | - Feature complete | - Sample Application | |
| | | | | | - Shell Module | | |
| | | | | | - BSIM test | | |
| | +-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | | Set Coordinator | 1.0.1 | 3.0 | - Feature complete | - Sample Application | |
| | | | | | - Shell Module | | |
| | | | | | - BSIM test | | |
| +--------+-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | CCP | Call Control Server | 1.0 | 3.0 | - Feature complete | - API refactor | |
| | | | | | - Shell Module | - Sample Application | |
| | | | | | - BSIM test | | |
| | +-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | | Call Control Client | 1.0 | 3.0 | - Feature complete | - API refactor | |
| | | | | | - Shell Module | - Sample Application | |
| | | | | | - BSIM test | | |
| +--------+-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | MCP | Media Control Server | 1.0 | 3.0 | - Feature complete | - API refactor | |
| | | | | | - Shell Module | - Support for multiple instances and connections | |
| | | | | | - BSIM test | - Sample Application | |
| | +-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | | Media Control Client | 1.0 | 3.0 | - Feature complete | - API refactor | |
| | | | | | - Shell Module | - Sample Application | |
| | | | | | - BSIM test | | |
| +--------+-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | BAP | Unicast Server | 1.0.1 | 3.0 | - Feature complete | | |
| | | | | | - Shell Module | | |
| | | | | | - BSIM test | | |
| | | | | | - Sample Application | | |
| | +-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | | Unicast Client | 1.0.1 | 3.0 | - Feature complete | | |
| | | | | | - Shell Module | | |
| | | | | | - BSIM test | | |
| | | | | | - Sample Application | | |
| | +-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | | Broadcast Source | 1.0.1 | 3.0 | - Feature complete | | |
| | | | | | - Shell Module | | |
| | | | | | - BSIM test | | |
| | | | | | - Sample Application | | |
| | +-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | | Broadcast Sink | 1.0.1 | 3.0 | - Feature complete | | |
| | | | | | - Shell Module | | |
| | | | | | - BSIM test | | |
| | | | | | - Sample Application | | |
| | +-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | | Scan Delegator | 1.0.1 | 3.3 | - Feature complete | | |
| | | | | | - Shell Module | | |
| | | | | | - BSIM test | | |
| | | | | | - Sample Application | | |
| | +-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | | Broadcast Assistant | 1.0.1 | 3.3 | - Feature complete | | |
| | | | | | - Shell Module | | |
| | | | | | - BSIM test | | |
| | | | | | - Sample Application | | |
| +--------+-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | CAP | Acceptor | 1.0 | 3.2 | - Feature complete | - Sample Application | |
| | | | | | - Shell Module | | |
| | | | | | - BSIM test | | |
| | +-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | | Initiator | 1.0 | 3.3 | - Feature complete | - Sample Application | |
| | | | | | - Shell Module | | |
| | | | | | - BSIM test | | |
| | +-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | | Commander | | | - WIP | - Feature complete | |
| | | | | | | - Shell Module | |
| | | | | | | - BSIM test | |
| | | | | | | - Sample Application | |
| +--------+-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | HAP | Hearing Aid | 1.0 | 3.1 | - Feature complete | | |
| | | | | | - Shell Module | | |
| | | | | | - BSIM test | | |
| | | | | | - Sample Application | | |
| | +-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | | Hearing Aid Unicast Client | 1.0 | 3.1 | - Feature complete | | |
| | | | | | - Shell Module | | |
| | | | | | - BSIM test | | |
| | | | | | - Sample Application | | |
| | +-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | | Hearing Aid Remote Controller | | | - WIP | - Feature complete | |
| | | | | | | - Shell Module | |
| | | | | | | - BSIM test | |
| | | | | | | - Sample Application | |
| +--------+-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | TMAP | Call Gateway | 1.0 | 3.4 | - Feature complete | | |
| | | | | | - Shell Module | | |
| | | | | | - BSIM test | | |
| | | | | | - Sample Application | | |
| | +-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | | Call Terminal | 1.0 | 3.4 | - Feature complete | | |
| | | | | | - Shell Module | | |
| | | | | | - BSIM test | | |
| | | | | | - Sample Application | | |
| | +-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | | Unicast Media Sender | 1.0 | 3.4 | - Feature complete | | |
| | | | | | - Shell Module | | |
| | | | | | - BSIM test | | |
| | | | | | - Sample Application | | |
| | +-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | | Unicast Media Receiver | 1.0 | 3.4 | - Feature complete | | |
| | | | | | - Shell Module | | |
| | | | | | - BSIM test | | |
| | | | | | - Sample Application | | |
| | +-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | | Broadcast Media Sender | 1.0 | 3.4 | - Feature complete | | |
| | | | | | - Shell Module | | |
| | | | | | - BSIM test | | |
| | | | | | - Sample Application | | |
| | +-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | | Broadcast Media Receiver | 1.0 | 3.4 | - Feature complete | | |
| | | | | | - Shell Module | | |
| | | | | | - BSIM test | | |
| | | | | | - Sample Application | | |
| +--------+-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | PBP | Public Broadcast Source | | 3.5 | - Feature complete | | |
| | | | | | - Shell Module | | |
| | | | | | - BSIM test | | |
| | | | | | - Sample Application | | |
| | +-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | | Public Broadcast Sink | | 3.5 | - Feature complete | | |
| | | | | | - Shell Module | | |
| | | | | | - BSIM test | | |
| | | | | | - Sample Application | | |
| | +-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | | Public Broadcast Assistant | | | | - Feature complete | |
| | | | | | | - Shell Module | |
| | | | | | | - BSIM test | |
| | | | | | | - Sample Application | |
| +--------+-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | GMAP | Unicast Game Gateway | | 3.5 | - Feature complete | - Sample Application | |
| | | | | | - Shell Module | | |
| | | | | | - BSIM test | | |
| | | | | | | | |
| | +-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | | Unicast Game Terminal | | 3.5 | - Feature complete | - Sample Application | |
| | | | | | - Shell Module | | |
| | | | | | - BSIM test | | |
| | | | | | | | |
| | +-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | | Broadcast Game Sender | | 3.5 | - Feature complete | - Sample Application | |
| | | | | | - Shell Module | | |
| | | | | | - BSIM test | | |
| | | | | | | | |
| | +-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| | | Broadcast Game Receiver | | 3.5 | - Feature complete | - Sample Application | |
| | | | | | - Shell Module | | |
| | | | | | - BSIM test | | |
| | | | | | | | |
| +--------+-------------------------------+---------+------------------+-----------------------+--------------------------------------------------+ |
| |
| Using the Bluetooth Audio Stack |
| =============================== |
| |
| To use any of the profiles in the Bluetooth Audio Stack, including the top-level |
| profiles outside of GAF, :kconfig:option:`CONFIG_BT_AUDIO` shall be enabled. |
| This Kconfig option allows the enabling of the individual profiles inside of the |
| Bluetooth Audio Stack. Each profile can generally be enabled on its own, but |
| enabling higher-layer profiles (such as CAP, TMAP and HAP) will typically |
| require enabling some of the lower layer profiles. |
| |
| It is, however, possible to create a device that uses e.g. only Stream Control |
| (with just the BAP), without using any of the content control or |
| rendering/capture control profiles, or vice versa. Using the higher layer |
| profiles will however typically provide a better user experience and better |
| interoperability with other devices. |
| |
| Common Audio Profile (CAP) |
| -------------------------- |
| |
| The Common Audio Profile introduces restrictions and requirements on the lower layer profiles. |
| The procedures in CAP works on one or more streams for one or more devices. Is it thus possible via |
| CAP to do a single function call to setup multiple streams across multiple devices. |
| |
| The figure below shows a complete structure of the procedures in CAP and |
| how they correspond to procedures from the other profiles. The circles with I, A and C show whether |
| the procedure has active involvement or requirements from the CAP Initiator, CAP Accept and CAP |
| Commander roles respectively. |
| |
| .. figure:: img/cap_proc.svg |
| :align: center |
| :alt: Common Audio Profile Procedures |
| |
| Common Audio Profile Procedures |
| |
| The API reference for CAP can be found in :ref:`Common Audio Profile <bluetooth_cap>`. |
| |
| Stream Control (BAP) |
| -------------------- |
| |
| Stream control is implemented by the Basic Audio Profile. This profile |
| defines multiple roles: |
| |
| * Unicast Client |
| * Unicast Server |
| * Broadcast Source |
| * Broadcast Sink |
| * Scan Delegator (not yet implemented) |
| * Broadcast assistant (not yet implemented) |
| |
| Each role can be enabled individually, and it is possible to support more than |
| one role. |
| |
| The API reference for stream control can be found in |
| :ref:`Bluetooth Audio <bluetooth_audio>`. |
| |
| |
| Rendering and Capture Control |
| ----------------------------- |
| |
| Rendering and capture control is implemented by the Volume Control Profile |
| (VCP) and Microphone Control Profile (MICP). |
| |
| The VCP implementation supports the following roles |
| |
| * Volume Control Service (VCS) Server |
| * Volume Control Service (VCS) Client |
| |
| The MICP implementation supports the following roles |
| |
| * Microphone Control Profile (MICP) Microphone Device (server) |
| * Microphone Control Profile (MICP) Microphone Controller (client) |
| |
| The API reference for volume control can be found in |
| :ref:`Bluetooth Volume Control <bluetooth_volume>`. |
| |
| The API reference for Microphone Control can be found in |
| :ref:`Bluetooth Microphone Control <bluetooth_microphone>`. |
| |
| |
| Content Control |
| --------------- |
| |
| Content control is implemented by the Call Control Profile (CCP) and |
| Media Control Profile (MCP). |
| |
| The CCP implementation is not yet implemented in Zephyr. |
| |
| The MCP implementation supports the following roles |
| |
| * Media Control Service (MCS) Server via the Media Proxy module |
| * Media Control Client (MCC) |
| |
| The API reference for media control can be found in |
| :ref:`Bluetooth Media Control <bluetooth_media>`. |
| |
| |
| Coordinated Sets |
| ---------------- |
| |
| Coordinated Sets is implemented by the Coordinated Sets Identification Profile |
| (CSIP). |
| |
| The CSIP implementation supports the following roles |
| |
| * Coordinated Set Identification Service (CSIP) Set Member |
| * Coordinated Set Identification Service (CSIP) Set Coordinator |
| |
| The API reference for media control can be found in |
| :ref:`Bluetooth Coordinated Sets <bluetooth_coordinated_sets>`. |
