add doc

docs/mkdocs/mkdocs.yml

@@ -44,6 +44,7 @@ nav:
     - Overview: apps_and_tools/index.md
     - Console: apps_and_tools/console.md
     - Bench: apps_and_tools/bench.md
+    - Speaker: apps_and_tools/speaker.md
     - HCI Bridge: apps_and_tools/hci_bridge.md
     - Golden Gate Bridge: apps_and_tools/gg_bridge.md
     - Show: apps_and_tools/show.md

docs/mkdocs/src/apps_and_tools/index.md

@@ -11,4 +11,5 @@ These include:
   * [HCI Bridge](hci_bridge.md) - a HCI transport bridge to connect two HCI transports and filter/snoop the HCI packets
   * [Golden Gate Bridge](gg_bridge.md) - a bridge between GATT and UDP to use with the Golden Gate "stack tool"
   * [Show](show.md) - Parse a file with HCI packets and print the details of each packet in a human readable form
+  * [Speaker](speaker.md) - Virtual Bluetooth speaker, with a command line and browser-based UI.
   * [Link Relay](link_relay.md) - WebSocket relay for virtual RemoteLink instances to communicate with each other.

docs/mkdocs/src/apps_and_tools/speaker.md

@@ -0,0 +1,86 @@
+SPEAKER APP
+===========
+
+![logo](../images/speaker_screenshot.png){ width=400 height=320 }
+
+The Speaker app is virtual Bluetooth speaker (A2DP sink).
+The app runs as a command-line executable, but also offers an optional simple
+web-browser-based user interface.
+
+# General Usage
+You can invoke the app either as `bumble-speaker` when installed as command
+from `pip`, or `python3 apps/speaker/speaker.py` when running from a source
+distribution.
+
+```
+Usage: speaker.py [OPTIONS] TRANSPORT
+
+  Run the speaker.
+
+Options:
+  --codec [sbc|aac]          [default: aac]
+  --discover                 Discover remote endpoints once connected
+  --output NAME              Send audio to this named output (may be used more
+                             than once for multiple outputs)
+  --ui-port HTTP_PORT        HTTP port for the UI server  [default: 7654]
+  --connect ADDRESS_OR_NAME  Address or name to connect to
+  --device-config FILENAME   Device configuration file
+  --help                     Show this message and exit.
+```
+
+# Connection
+By default, the virtual speaker will wait for another device (like a phone or
+computer) to connect to it (and possibly pair). Alternatively, the speaker can
+be told to initiate a connection to a remote device, using the `--connect` 
+option.
+
+# Outputs
+The speaker can have one or more outputs. By default, the only output is a text
+display on the console, as well as a browser-based user interface if connected.
+In addition, a file output can be used, in which case the received audio data is
+saved to a specified file.
+Finally, if the host computer on which your are running the application has `ffplay`
+as an available command line executable, the `@ffplay` output can be selected, in 
+which case the received audio will be played on the computer's builtin speakers via
+a pipe to `ffplay`. (see the [ffplay documentation](https://www.ffmpeg.org/ffplay.html)
+for details)
+
+# Web User Interface
+When the speaker app starts, it prints out on the console the local URL at which you
+may point a browser (Chrome recommended for full functionality). The console line
+specifying the local UI URL will look like:
+```
+UI HTTP server at http://127.0.0.1:7654
+```
+
+By default, the web UI will show the status of the connection, as well as a realtime
+graph of the received audio bandwidth.
+In order to also hear the received audio, you need to click the `Audio on` button
+(this is due to the fact that most browsers will require some user interface with the
+page before granting access to the audio output APIs).
+
+# Examples
+
+In the following examples, we use a single USB Bluetooth controllers `usb:0`. Other 
+transports can be used of course.
+
+!!! example "Start the speaker and wait for a connection"
+    ```
+    $ bumble-speaker usb:0
+    ```
+
+!!! example "Start the speaker and save the AAC audio to a file named `audio.aac`."
+    ```
+    $ bumble-speaker --output audio.aac usb:0
+    ```
+
+!!! example "Start the speaker and save the SBC audio to a file named `audio.sbc`."
+    ```
+    $ bumble-speaker --codec sbc --output audio.sbc usb:0
+    ```
+
+!!! example "Start the speaker and connect it to a phone at address `B8:7B:C5:05:57:ED`."
+    ```
+    $ bumble-speaker --connect B8:7B:C5:05:57:ED usb:0
+    ```
+