Shadowtrance
23 lines
1.1 KiB
Markdown
23 lines
1.1 KiB
Markdown
# Audio stream module
|
|
|
|
Defines `AUDIO_STREAM_TYPE` and `AudioStreamApi`: the high-level, full-duplex
|
|
audio API that apps (including ELF side-loaded apps) and `AudioService` should
|
|
use instead of talking to an `AUDIO_CODEC_TYPE` device directly. Binds to one
|
|
input-capable and/or one output-capable codec device (found automatically at
|
|
start; see `Drivers/audio-codec-module`) and adds on top of it:
|
|
|
|
- Resampling, so the same app code works at any requested sample rate
|
|
regardless of what rate the bound codec natively runs at.
|
|
- Shared volume/mute/enable state per direction, with a change callback
|
|
(`AudioStreamChangeCallback`) that `AudioService` subscribes to.
|
|
- A single always-present device (`audio-stream0`), constructed unconditionally
|
|
at module-start time before any devicetree codec exists, and bound lazily on
|
|
first use -- so boards with no audio hardware at all still get a harmless,
|
|
inert device rather than nothing.
|
|
|
|
`open_input`/`open_output` return a stream handle; `read`/`write` on that
|
|
handle are blocking and must be called from the caller's own task, never from
|
|
the main/LVGL thread.
|
|
|
|
License: [Apache v2.0](LICENSE-Apache-2.0.md)
|