Add camera documentation

PR #4213 <#4213>

README.md

@@ -25,12 +25,13 @@ It focuses on:
 [lowlatency]: https://github.com/Genymobile/scrcpy/pull/646
 
 Its features include:
- - [audio forwarding](doc/audio.md) (Android >= 11)
+ - [audio forwarding](doc/audio.md) (Android 11+)
  - [recording](doc/recording.md)
  - mirroring with [Android device screen off](doc/device.md#turn-screen-off)
  - [copy-paste](doc/control.md#copy-paste) in both directions
  - [configurable quality](doc/video.md)
- - Android device screen [as a webcam (V4L2)](doc/v4l2.md) (Linux-only)
+ - [camera mirroring](doc/camera.md) (Android 12+)
+ - [mirroring as a webcam (V4L2)](doc/v4l2.md) (Linux-only)
  - [physical keyboard/mouse simulation (HID)](doc/hid-otg.md)
  - [OTG mode](doc/hid-otg.md#otg)
  - and more…
@@ -77,6 +78,7 @@ documented in the following pages:
  - [Recording](doc/recording.md)
  - [Tunnels](doc/tunnels.md)
  - [HID/OTG](doc/hid-otg.md)
+ - [Camera](doc/camera.md)
  - [Video4Linux](doc/v4l2.md)
  - [Shortcuts](doc/shortcuts.md)
 

doc/camera.md

@@ -0,0 +1,150 @@
+# Camera
+
+Camera mirroring is supported for devices with Android 12 or higher.
+
+To capture the camera instead of the device screen:
+
+```
+scrcpy --video-source=camera
+```
+
+By default, it automatically switches [audio source](audio.md#source) to
+microphone (as if `--audio-source=mic` were also passed).
+
+```bash
+scrcpy --video-source=display  # default is --audio-source=output
+scrcpy --video-source=camera   # default is --audio-source=mic
+scrcpy --video-source=display --audio-source=mic    # force display AND microphone
+scrcpy --video-source=camera --audio-source=output  # force camera AND device audio output
+```
+
+
+## List
+
+To list the cameras available (with their declared valid sizes and frame rates):
+
+```
+scrcpy --list-cameras
+scrcpy --list-camera-sizes
+```
+
+_Note that the sizes and frame rates are declarative. They are not accurate on
+all devices: some of them are declared but not supported, while some others are
+not declared but supported._
+
+
+## Selection
+
+It is possible to pass an explicit camera id (as listed by `--list-cameras`):
+
+```
+scrcpy --video-source=camera --camera-id=0
+```
+
+Alternatively, the camera may be selected automatically:
+
+```bash
+scrcpy --video-source=camera                           # use the first camera
+scrcpy --video-source=camera --camera-facing=front     # use the first front camera
+scrcpy --video-source=camera --camera-facing=back      # use the first back camera
+scrcpy --video-source=camera --camera-facing=external  # use the first external camera
+```
+
+If `--camera-id` is specified, then `--camera-facing` is forbidden (the id
+already determines the camera):
+
+```bash
+scrcpy --video-source=camera --camera-id=0 --camera-facing=front  # error
+```
+
+
+### Size selection
+
+It is possible to pass an explicit camera size:
+
+```
+scrcpy --video-source=camera --camera-size=1920x1080
+```
+
+The given size may be listed among the declared valid sizes
+(`--list-camera-sizes`), but may also be anything else (some devices support
+arbitrary sizes):
+
+```
+scrcpy --video-source=camera --camera-size=1840x444
+```
+
+Alternatively, a declared valid size (among the ones listed by
+`list-camera-sizes`) may be selected automatically.
+
+Two constraints are supported:
+ - `-m`/`--max-size` (already used for display mirroring), for example `-m1920`;
+ - `--camera-ar` to specify an aspect ratio (`<num>:<den>`, `<value>` or
+   `sensor`).
+
+Some examples:
+
+```bash
+scrcpy --video-source=camera                          # use the greatest width and the greatest associated height
+scrcpy --video-source=camera -m1920                   # use the greatest width not above 1920 and the greatest associated height
+scrcpy --video-source=camera --camera-ar=4:3          # use the greatest size with an aspect ratio of 4:3 (+/- 10%)
+scrcpy --video-source=camera --camera-ar=1.6          # use the greatest size with an aspect ratio of 1.6 (+/- 10%)
+scrcpy --video-source=camera --camera-ar=sensor       # use the greatest size with the aspect ratio of the camera sensor (+/- 10%)
+scrcpy --video-source=camera -m1920 --camera-ar=16:9  # use the greatest width not above 1920 and the closest to 16:9 aspect ratio
+```
+
+If `--camera-size` is specified, then `-m`/`--max-size` and `--camera-ar` are
+forbidden (the size is determined by the value given explicitly):
+
+```bash
+scrcpy --video-source=camera --camera-size=1920x1080 -m3000  # error
+```
+
+
+## Frame rate
+
+By default, camera is captured at Android's default frame rate (30 fps).
+
+To configure a different frame rate:
+
+```
+scrcpy --video-source=camera --camera-fps=60
+```
+
+
+## High speed capture
+
+The Android camera API also supports a [high speed capture mode][high speed].
+
+This mode is restricted to specific resolutions and frame rates, listed by
+`--list-camera-sizes`.
+
+```
+scrcpy --video-source=camera --camera-size=1920x1080 --camera-fps=240
+```
+
+[high speed]: https://developer.android.com/reference/android/hardware/camera2/CameraConstrainedHighSpeedCaptureSession
+
+
+## Brace expansion tip
+
+All camera options start with `--camera-`, so if your shell supports it, you can
+benefit from [brace expansion] (for example, it is supported _bash_ and _zsh_):
+
+```bash
+scrcpy --video-source=camera --camera-{facing=back,ar=16:9,high-speed,fps=120}
+```
+
+This will be expanded as:
+
+```bash
+scrcpy --video-source=camera --camera-facing=back --camera-ar=16:9 --camera-high-speed --camera-fps=120
+```
+
+[brace expansion]: https://www.gnu.org/software/bash/manual/html_node/Brace-Expansion.html
+
+
+## Webcam
+
+Combined with the [V4L2](v4l2.md) feature on Linux, the Android device camera
+may be used as a webcam on the computer.

doc/video.md

@@ -1,5 +1,14 @@
 # Video
 
+## Source
+
+By default, scrcpy mirrors the device screen.
+
+It is possible to capture the device camera instead.
+
+See the dedicated [camera](camera.md) page.
+
+
 ## Size
 
 By default, scrcpy attempts to mirror at the Android device resolution.