diff options
Diffstat (limited to 'docs/4a-framework/concepts.md')
| -rw-r--r-- | docs/4a-framework/concepts.md | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/docs/4a-framework/concepts.md b/docs/4a-framework/concepts.md new file mode 100644 index 0000000..c0f0f1d --- /dev/null +++ b/docs/4a-framework/concepts.md @@ -0,0 +1,16 @@ +# Concepts +A user application requests to open an audio role, which is bound to a stream, which is bound to a zone. This allows the application to only care about the audio role. + +For example, a navigation application can request the **navigation** role, which is bound to the **navigation** stream defined by the HAL. This stream is bound to the **driver** zone, which is the closest speaker to the driver. + +## Roles +The high level API allows applications to open roles such as **emergency**, **navigation** or **multimedia**. A role is bound to a stream, which is basically a device URI. When a role is opened, then the policy engine is notified and executes an interrupt on every other opened roles with a lower priority. An interrupt is a policy engine function that can change the volume, mute or unmute, change the stream's state. + +This behaviour allows the policy engine to take actions like lowering the radio volume when an application wants to play something on the emergency role. + +## Streams +A stream is basically a device URI that you can open to write audio data. For exemple, it can be "hw:2,0,1", which means that you have to use this as an alsa device URI. + +## Zones +Multiple speakers are spread arround inside a vehicule, they are named depending on their position, like **front-center**, **front-left**, **front-right**, **rear-left**, **rear-right**, etc... +Zones are an abstraction of positional audio. A zone is made of one or more speakers and describes logical audio areas like **driver**, **front**, **rear**, etc. |