Support USB HID over AoAv2 mode for keyboard input

This provides a better input experience via
simulate physical keyboard, it converts
SDL_KeyboardEvent to proper HID events and send it
via HID over AoAv2.

This is a rewriting and bugfix of the origin code
from [@amosbird](https://github.com/amosbird).

Make sdl_keymod_to_hid_modifiers() more readable

Support MOD keys in HID mode

Enable Ctrl+V on HID mode

Support to send media events from hid_keyboard

Use existing --serial to replace --usb

Use explict option for input mode

Move HID keyboard setup code into functions

Send HID events in separated thread

Let libusb handle max package size

Fix HID keyboard report desc

BUILD.md

@@ -88,11 +88,12 @@ Install the required packages from your package manager.
 
 ```bash
 # runtime dependencies
-sudo apt install ffmpeg libsdl2-2.0-0 adb
+sudo apt install ffmpeg libsdl2-2.0-0 adb libusb-1.0-0
 
 # client build dependencies
 sudo apt install gcc git pkg-config meson ninja-build libsdl2-dev \
-                 libavcodec-dev libavdevice-dev libavformat-dev libavutil-dev
+                 libavcodec-dev libavdevice-dev libavformat-dev libavutil-dev\
+                 libusb-dev
 
 # server build dependencies
 sudo apt install openjdk-11-jdk
@@ -114,7 +115,7 @@ pip3 install meson
 sudo dnf install https://download1.rpmfusion.org/free/fedora/rpmfusion-free-release-$(rpm -E %fedora).noarch.rpm
 
 # client build dependencies
-sudo dnf install SDL2-devel ffms2-devel meson gcc make
+sudo dnf install SDL2-devel ffms2-devel libusb-devel meson gcc make
 
 # server build dependencies
 sudo dnf install java-devel
@@ -159,7 +160,8 @@ install the required packages:
 ```bash
 # runtime dependencies
 pacman -S mingw-w64-x86_64-SDL2 \
-          mingw-w64-x86_64-ffmpeg
+          mingw-w64-x86_64-ffmpeg \
+          mingw-w64-x86_64-libusb
 
 # client build dependencies
 pacman -S mingw-w64-x86_64-make \
@@ -173,7 +175,8 @@ For a 32 bits version, replace `x86_64` by `i686`:
 ```bash
 # runtime dependencies
 pacman -S mingw-w64-i686-SDL2 \
-          mingw-w64-i686-ffmpeg
+          mingw-w64-i686-ffmpeg \
+          mingw-w64-i686-libusb
 
 # client build dependencies
 pacman -S mingw-w64-i686-make \
@@ -197,7 +200,7 @@ Install the packages with [Homebrew]:
 
 ```bash
 # runtime dependencies
-brew install sdl2 ffmpeg
+brew install sdl2 ffmpeg libusb
 
 # client build dependencies
 brew install pkg-config meson

README.md

@@ -207,7 +207,6 @@ scrcpy --crop 1224:1440:0:0   # 1224x1440 at offset (0,0)
 
 If `--max-size` is also specified, resizing is applied after cropping.
 
-
 #### Lock video orientation
 
 

app/meson.build

@@ -1,6 +1,7 @@
 src = [
     'src/main.c',
     'src/adb.c',
+    'src/aoa_hid.c',
     'src/cli.c',
     'src/clock.c',
     'src/compat.c',
@@ -12,6 +13,7 @@ src = [
     'src/file_handler.c',
     'src/fps_counter.c',
     'src/frame_buffer.c',
+    'src/hid_keyboard.c',
     'src/input_manager.c',
     'src/opengl.c',
     'src/receiver.c',
@@ -54,6 +56,7 @@ if not get_option('crossbuild_windows')
         dependency('libavformat'),
         dependency('libavcodec'),
         dependency('libavutil'),
+        dependency('libusb-1.0'),
         dependency('sdl2'),
     ]
 
@@ -62,7 +65,7 @@ if not get_option('crossbuild_windows')
     endif
 
 else
-
+    # TODO: add libusb dependency for windows.
     # cross-compile mingw32 build (from Linux to Windows)
     prebuilt_sdl2 = meson.get_cross_property('prebuilt_sdl2')
     sdl2_bin_dir = meson.current_source_dir() + '/../prebuilt-deps/' + prebuilt_sdl2 + '/bin'

app/scrcpy.1

@@ -82,6 +82,18 @@ Start in fullscreen.
 .B \-h, \-\-help
 Print this help.
 
+.TP
+.B \-i, \-\-input\-mode mode
+Select input mode for keyboard events.
+
+Possible values are "auto", "hid" and "inject".
+
+"auto" is default if not specified, which attemps "hid" first and will fallback to "inject" if failed.
+
+"hid" uses Android's USB HID over AOAv2 feature to simulate physical keyboard's events, which provides better experience for IME users if supported by you device.
+
+"inject" is the legacy scrcpy way by injecting keycode events on Android, works on most devices.
+
 .TP
 .B \-\-legacy\-paste
 Inject computer clipboard text as a sequence of key events on Ctrl+v (like MOD+Shift+v).

app/src/adb.c

@@ -224,3 +224,10 @@ adb_install(const char *serial, const char *local) {
 
     return proc;
 }
+
+process_t
+adb_get_serialno(const char *serial) {
+    const char *const adb_cmd[] = {"get-serialno"};
+    process_t proc = adb_execute(serial, adb_cmd, ARRAY_LEN(adb_cmd));
+    return proc;
+}

app/src/adb.h

@@ -31,4 +31,7 @@ adb_push(const char *serial, const char *local, const char *remote);
 process_t
 adb_install(const char *serial, const char *local);
 
+process_t
+adb_get_serialno(const char *serial);
+
 #endif