Fail-fast camera mirroring on Android 11 and older

Co-authored-by: Romain Vimont <rom@rom1v.com>
Signed-off-by: Romain Vimont <rom@rom1v.com>

app/data/bash-completion/scrcpy

@@ -10,10 +10,14 @@ _scrcpy() {
         --audio-source=
         --audio-output-buffer=
         -b --video-bit-rate=
+        --camera-ar=
+        --camera-id=
+        --camera-facing=
+        --camera-size=
         --crop=
         -d --select-usb
         --disable-screensaver
-        --display=
+        --display-id=
         --display-buffer=
         -e --select-tcpip
         -f --fullscreen
@@ -74,6 +78,7 @@ _scrcpy() {
         --video-codec=
         --video-codec-options=
         --video-encoder=
+        --video-source=
         -w --stay-awake
         --window-borderless
         --window-title=
@@ -93,10 +98,18 @@ _scrcpy() {
             COMPREPLY=($(compgen -W 'opus aac raw' -- "$cur"))
             return
             ;;
+        --video-source)
+            COMPREPLY=($(compgen -W 'display camera' -- "$cur"))
+            return
+            ;;
         --audio-source)
             COMPREPLY=($(compgen -W 'output mic' -- "$cur"))
             return
             ;;
+        --camera-facing)
+            COMPREPLY=($(compgen -W 'front back external' -- "$cur"))
+            return
+            ;;
         --lock-video-orientation)
             COMPREPLY=($(compgen -W 'unlocked initial 0 1 2 3' -- "$cur"))
             return
@@ -141,8 +154,11 @@ _scrcpy() {
         |--audio-codec-options \
         |--audio-encoder \
         |--audio-output-buffer \
+        |--camera-ar \
+        |--camera-id \
+        |--camera-size \
         |--crop \
-        |--display \
+        |--display-id \
         |--display-buffer \
         |--max-fps \
         |-m|--max-size \

app/data/zsh-completion/_scrcpy

@@ -17,10 +17,14 @@ arguments=(
     '--audio-source=[Select the audio source]:source:(output mic)'
     '--audio-output-buffer=[Configure the size of the SDL audio output buffer (in milliseconds)]'
     {-b,--video-bit-rate=}'[Encode the video at the given bit-rate]'
+    '--camera-ar=[Select the camera size by its aspect ratio]'
+    '--camera-id=[Specify the camera id to mirror]'
+    '--camera-facing=[Select the device camera by its facing direction]:facing:(front back external)'
+    '--camera-size=[Specify an explicit camera capture size]'
     '--crop=[\[width\:height\:x\:y\] Crop the device screen on the server]'
     {-d,--select-usb}'[Use USB device]'
     '--disable-screensaver[Disable screensaver while scrcpy is running]'
-    '--display=[Specify the display id to mirror]'
+    '--display-id=[Specify the display id to mirror]'
     '--display-buffer=[Add a buffering delay \(in milliseconds\) before displaying]'
     {-e,--select-tcpip}'[Use TCP/IP device]'
     {-f,--fullscreen}'[Start in fullscreen]'
@@ -78,6 +82,7 @@ arguments=(
     '--video-codec=[Select the video codec]:codec:(h264 h265 av1)'
     '--video-codec-options=[Set a list of comma-separated key\:type=value options for the device video encoder]'
     '--video-encoder=[Use a specific MediaCodec video encoder]'
+    '--video-source=[Select the video source]:source:(display camera)'
     {-w,--stay-awake}'[Keep the device on while scrcpy is running, when the device is plugged in]'
     '--window-borderless[Disable window decorations \(display borderless window\)]'
     '--window-title=[Set a custom window title]'

app/scrcpy.1

@@ -75,6 +75,28 @@ Encode the video at the given bit rate, expressed in bits/s. Unit suffixes are s
 
 Default is 8M (8000000).
 
+.TP
+.BI "\-\-camera\-ar " ar
+Select the camera size by its aspect ratio (+/- 10%).
+
+Possible values are "sensor" (use the camera sensor aspect ratio), "<num>:<den>" (e.g. "4:3") and "<value>" (e.g. "1.6").
+
+.TP
+.BI "\-\-camera\-id " id
+Specify the device camera id to mirror.
+
+The available camera ids can be listed by \-\-list\-cameras.
+
+.TP
+.BI "\-\-camera\-facing " facing
+Select the device camera by its facing direction.
+
+Possible values are "front", "back" and "external".
+
+.TP
+.BI "\-\-camera\-size " width\fRx\fIheight
+Specify an explicit camera capture size.
+
 .TP
 .BI "\-\-crop " width\fR:\fIheight\fR:\fIx\fR:\fIy
 Crop the device screen on the server.
@@ -94,7 +116,7 @@ Also see \fB\-e\fR (\fB\-\-select\-tcpip\fR).
 Disable screensaver while scrcpy is running.
 
 .TP
-.BI "\-\-display " id
+.BI "\-\-display\-id " id
 Specify the device display id to mirror.
 
 The available display ids can be listed by \-\-list\-displays.
@@ -432,6 +454,14 @@ Use a specific MediaCodec video encoder (depending on the codec provided by \fB\
 
 The available encoders can be listed by \-\-list\-encoders.
 
+.TP
+.BI "\-\-video\-source " source
+Select the video source (display or camera).
+
+Camera mirroring requires Android 12+.
+
+Default is display.
+
 .TP
 .B \-w, \-\-stay-awake
 Keep the device on while scrcpy is running, when the device is plugged in.

app/src/adb/adb.c

@@ -218,8 +218,16 @@ sc_adb_forward(struct sc_intr *intr, const char *serial, uint16_t local_port,
                const char *device_socket_name, unsigned flags) {
     char local[4 + 5 + 1]; // tcp:PORT
     char remote[108 + 14 + 1]; // localabstract:NAME
-    sprintf(local, "tcp:%" PRIu16, local_port);
-    snprintf(remote, sizeof(remote), "localabstract:%s", device_socket_name);
+
+    int r = snprintf(local, sizeof(local), "tcp:%" PRIu16, local_port);
+    assert(r >= 0 && (size_t) r < sizeof(local));
+
+    r = snprintf(remote, sizeof(remote), "localabstract:%s",
+                 device_socket_name);
+    if (r < 0 || (size_t) r >= sizeof(remote)) {
+        LOGE("Could not write socket name");
+        return false;
+    }
 
     assert(serial);
     const char *const argv[] =
@@ -233,7 +241,9 @@ bool
 sc_adb_forward_remove(struct sc_intr *intr, const char *serial,
                       uint16_t local_port, unsigned flags) {
     char local[4 + 5 + 1]; // tcp:PORT
-    sprintf(local, "tcp:%" PRIu16, local_port);
+    int r = snprintf(local, sizeof(local), "tcp:%" PRIu16, local_port);
+    assert(r >= 0 && (size_t) r < sizeof(local));
+    (void) r;
 
     assert(serial);
     const char *const argv[] =
@@ -249,8 +259,16 @@ sc_adb_reverse(struct sc_intr *intr, const char *serial,
                unsigned flags) {
     char local[4 + 5 + 1]; // tcp:PORT
     char remote[108 + 14 + 1]; // localabstract:NAME
-    sprintf(local, "tcp:%" PRIu16, local_port);
-    snprintf(remote, sizeof(remote), "localabstract:%s", device_socket_name);
+    int r = snprintf(local, sizeof(local), "tcp:%" PRIu16, local_port);
+    assert(r >= 0 && (size_t) r < sizeof(local));
+
+    r = snprintf(remote, sizeof(remote), "localabstract:%s",
+                 device_socket_name);
+    if (r < 0 || (size_t) r >= sizeof(remote)) {
+        LOGE("Could not write socket name");
+        return false;
+    }
+
     assert(serial);
     const char *const argv[] =
         SC_ADB_COMMAND("-s", serial, "reverse", remote, local);
@@ -263,7 +281,12 @@ bool
 sc_adb_reverse_remove(struct sc_intr *intr, const char *serial,
                       const char *device_socket_name, unsigned flags) {
     char remote[108 + 14 + 1]; // localabstract:NAME
-    snprintf(remote, sizeof(remote), "localabstract:%s", device_socket_name);
+    int r = snprintf(remote, sizeof(remote), "localabstract:%s",
+                     device_socket_name);
+    if (r < 0 || (size_t) r >= sizeof(remote)) {
+        LOGE("Device socket name too long");
+        return false;
+    }
 
     assert(serial);
     const char *const argv[] =
@@ -333,7 +356,9 @@ bool
 sc_adb_tcpip(struct sc_intr *intr, const char *serial, uint16_t port,
              unsigned flags) {
     char port_string[5 + 1];
-    sprintf(port_string, "%" PRIu16, port);
+    int r = snprintf(port_string, sizeof(port_string), "%" PRIu16, port);
+    assert(r >= 0 && (size_t) r < sizeof(port_string));
+    (void) r;
 
     assert(serial);
     const char *const argv[] =

app/src/cli.c

@@ -32,6 +32,7 @@ enum {
     OPT_WINDOW_BORDERLESS,
     OPT_MAX_FPS,
     OPT_LOCK_VIDEO_ORIENTATION,
+    OPT_DISPLAY,
     OPT_DISPLAY_ID,
     OPT_ROTATION,
     OPT_RENDER_DRIVER,
@@ -85,6 +86,8 @@ enum {
     OPT_LIST_CAMERA_SIZES,
     OPT_CAMERA_ID,
     OPT_CAMERA_SIZE,
+    OPT_CAMERA_FACING,
+    OPT_CAMERA_AR,
 };
 
 struct sc_option {
@@ -201,15 +204,29 @@ static const struct sc_option options[] = {
         .longopt = "bit-rate",
         .argdesc = "value",
     },
+    {
+        .longopt_id = OPT_CAMERA_AR,
+        .longopt = "camera-ar",
+        .argdesc = "ar",
+        .text = "Select the camera size by its aspect ratio (+/- 10%).\n"
+                "Possible values are \"sensor\" (use the camera sensor aspect "
+                "ratio), \"<num>:<den>\" (e.g. \"4:3\") or \"<value>\" (e.g. "
+                "\"1.6\")."
+    },
     {
         .longopt_id = OPT_CAMERA_ID,
-        .longopt = "camera",
+        .longopt = "camera-id",
         .argdesc = "id",
-        .text = "Specify the device camera id to mirror when using "
-                "--video-source=camera.\n"
+        .text = "Specify the device camera id to mirror.\n"
                 "The available camera ids can be listed by:\n"
-                "    scrcpy --list-cameras\n"
-                "Default is \"auto\" (the first one)",
+                "    scrcpy --list-cameras",
+    },
+    {
+        .longopt_id = OPT_CAMERA_FACING,
+        .longopt = "camera-facing",
+        .argdesc = "facing",
+        .text = "Select the device camera by its facing direction.\n"
+                "Possible values are \"front\", \"back\" and \"external\".",
     },
     {
         .longopt_id = OPT_CAMERA_SIZE,
@@ -253,9 +270,15 @@ static const struct sc_option options[] = {
         .text = "Disable screensaver while scrcpy is running.",
     },
     {
-        .longopt_id = OPT_DISPLAY_ID,
+        // deprecated
+        .longopt_id = OPT_DISPLAY,
         .longopt = "display",
         .argdesc = "id",
+    },
+    {
+        .longopt_id = OPT_DISPLAY_ID,
+        .longopt = "display-id",
+        .argdesc = "id",
         .text = "Specify the device display id to mirror.\n"
                 "The available display ids can be listed by:\n"
                 "    scrcpy --list-displays\n"
@@ -720,6 +743,7 @@ static const struct sc_option options[] = {
         .longopt = "video-source",
         .argdesc = "source",
         .text = "Select the video source (display or camera).\n"
+                "Camera mirroring requires Android 12+.\n"
                 "Default is display.",
     },
     {
@@ -1694,6 +1718,34 @@ parse_audio_source(const char *optarg, enum sc_audio_source *source) {
     return false;
 }
 
+static bool
+parse_camera_facing(const char *optarg, enum sc_camera_facing *facing) {
+    if (!strcmp(optarg, "front")) {
+        *facing = SC_CAMERA_FACING_FRONT;
+        return true;
+    }
+
+    if (!strcmp(optarg, "back")) {
+        *facing = SC_CAMERA_FACING_BACK;
+        return true;
+    }
+
+    if (!strcmp(optarg, "external")) {
+        *facing = SC_CAMERA_FACING_EXTERNAL;
+        return true;
+    }
+
+    if (*optarg == '\0') {
+        // Empty string is a valid value (equivalent to not passing the option)
+        *facing = SC_CAMERA_FACING_ANY;
+        return true;
+    }
+
+    LOGE("Unsupported camera facing: %s (expected front, back or external)",
+         optarg);
+    return false;
+}
+
 static bool
 parse_time_limit(const char *s, sc_tick *tick) {
     long value;
@@ -1756,6 +1808,9 @@ parse_args_with_getopt(struct scrcpy_cli_args *args, int argc, char *argv[],
             case OPT_CROP:
                 opts->crop = optarg;
                 break;
+            case OPT_DISPLAY:
+                LOGW("--display is deprecated, use --display-id instead.");
+                // fall through
             case OPT_DISPLAY_ID:
                 if (!parse_display_id(optarg, &opts->display_id)) {
                     return false;
@@ -2085,12 +2140,20 @@ parse_args_with_getopt(struct scrcpy_cli_args *args, int argc, char *argv[],
                     return false;
                 }
                 break;
+            case OPT_CAMERA_AR:
+                opts->camera_ar = optarg;
+                break;
             case OPT_CAMERA_ID:
                 opts->camera_id = optarg;
                 break;
             case OPT_CAMERA_SIZE:
                 opts->camera_size = optarg;
                 break;
+            case OPT_CAMERA_FACING:
+                if (!parse_camera_facing(optarg, &opts->camera_facing)) {
+                    return false;
+                }
+                break;
             default:
                 // getopt prints the error message on stderr
                 return false;
@@ -2185,27 +2248,44 @@ parse_args_with_getopt(struct scrcpy_cli_args *args, int argc, char *argv[],
     }
 
     if (opts->video_source == SC_VIDEO_SOURCE_CAMERA) {
+        if (opts->display_id) {
+            LOGE("--display-id is only available with --video-source=display");
+            return false;
+        }
+
         if (opts->lock_video_orientation !=
                 SC_LOCK_VIDEO_ORIENTATION_UNLOCKED) {
             LOGE("--lock-video-orientation is not supported for camera");
             return false;
         }
 
-        if (!opts->camera_id) {
-            LOGE("Camera id must be specified by --camera=ID "
-                 "(list the available ids with --list-cameras)");
+        if (opts->camera_id && opts->camera_facing != SC_CAMERA_FACING_ANY) {
+            LOGE("Could not specify both --camera-id and --camera-facing");
             return false;
         }
 
-        if (!opts->camera_size) {
-            LOGE("Camera size must be specified by --camera-size=WIDTHxHEIGHT");
-            return false;
+        if (opts->camera_size) {
+            if (opts->camera_ar) {
+                LOGE("Could not specify both --camera-size and -m/--max-size");
+                return false;
+            }
+
+            if (opts->camera_ar) {
+                LOGE("Could not specify both --camera-size and --camera-ar");
+                return false;
+            }
         }
 
         if (opts->control) {
             LOGI("Camera video source: control disabled");
             opts->control = false;
         }
+    } else if (opts->camera_id
+            || opts->camera_ar
+            || opts->camera_facing != SC_CAMERA_FACING_ANY
+            || opts->camera_size) {
+        LOGE("Camera options are only available with --video-source=camera");
+        return false;
     }
 
     if (opts->audio && opts->audio_source == SC_AUDIO_SOURCE_AUTO) {

app/src/options.c

@@ -13,6 +13,7 @@ const struct scrcpy_options scrcpy_options_default = {
     .audio_encoder = NULL,
     .camera_id = NULL,
     .camera_size = NULL,
+    .camera_ar = NULL,
     .log_level = SC_LOG_LEVEL_INFO,
     .video_codec = SC_CODEC_H264,
     .audio_codec = SC_CODEC_OPUS,
@@ -21,6 +22,7 @@ const struct scrcpy_options scrcpy_options_default = {
     .record_format = SC_RECORD_FORMAT_AUTO,
     .keyboard_input_mode = SC_KEYBOARD_INPUT_MODE_INJECT,
     .mouse_input_mode = SC_MOUSE_INPUT_MODE_INJECT,
+    .camera_facing = SC_CAMERA_FACING_ANY,
     .port_range = {
         .first = DEFAULT_LOCAL_PORT_RANGE_FIRST,
         .last = DEFAULT_LOCAL_PORT_RANGE_LAST,

app/src/options.h

@@ -55,6 +55,13 @@ enum sc_audio_source {
     SC_AUDIO_SOURCE_MIC,
 };
 
+enum sc_camera_facing {
+    SC_CAMERA_FACING_ANY,
+    SC_CAMERA_FACING_FRONT,
+    SC_CAMERA_FACING_BACK,
+    SC_CAMERA_FACING_EXTERNAL,
+};
+
 enum sc_lock_video_orientation {
     SC_LOCK_VIDEO_ORIENTATION_UNLOCKED = -1,
     // lock the current orientation when scrcpy starts
@@ -125,6 +132,7 @@ struct scrcpy_options {
     const char *audio_encoder;
     const char *camera_id;
     const char *camera_size;
+    const char *camera_ar;
     enum sc_log_level log_level;
     enum sc_codec video_codec;
     enum sc_codec audio_codec;
@@ -133,6 +141,7 @@ struct scrcpy_options {
     enum sc_record_format record_format;
     enum sc_keyboard_input_mode keyboard_input_mode;
     enum sc_mouse_input_mode mouse_input_mode;
+    enum sc_camera_facing camera_facing;
     struct sc_port_range port_range;
     uint32_t tunnel_host;
     uint16_t tunnel_port;

app/src/scrcpy.c

@@ -353,6 +353,7 @@ scrcpy(struct scrcpy_options *options) {
         .audio_codec = options->audio_codec,
         .video_source = options->video_source,
         .audio_source = options->audio_source,
+        .camera_facing = options->camera_facing,
         .crop = options->crop,
         .port_range = options->port_range,
         .tunnel_host = options->tunnel_host,
@@ -374,6 +375,7 @@ scrcpy(struct scrcpy_options *options) {
         .audio_encoder = options->audio_encoder,
         .camera_id = options->camera_id,
         .camera_size = options->camera_size,
+        .camera_ar = options->camera_ar,
         .force_adb_forward = options->force_adb_forward,
         .power_off_on_close = options->power_off_on_close,
         .clipboard_autosync = options->clipboard_autosync,

app/src/server.c

@@ -77,6 +77,7 @@ sc_server_params_destroy(struct sc_server_params *params) {
     free((char *) params->audio_encoder);
     free((char *) params->tcpip_dst);
     free((char *) params->camera_id);
+    free((char *) params->camera_ar);
 }
 
 static bool
@@ -105,6 +106,7 @@ sc_server_params_copy(struct sc_server_params *dst,
     COPY(audio_encoder);
     COPY(tcpip_dst);
     COPY(camera_id);
+    COPY(camera_ar);
 #undef COPY
 
     return true;
@@ -183,6 +185,20 @@ sc_server_get_codec_name(enum sc_codec codec) {
     }
 }
 
+static const char *
+sc_server_get_camera_facing_name(enum sc_camera_facing camera_facing) {
+    switch (camera_facing) {
+        case SC_CAMERA_FACING_FRONT:
+            return "front";
+        case SC_CAMERA_FACING_BACK:
+            return "back";
+        case SC_CAMERA_FACING_EXTERNAL:
+            return "external";
+        default:
+            return NULL;
+    }
+}
+
 static sc_pid
 execute_server(struct sc_server *server,
                const struct sc_server_params *params) {
@@ -285,6 +301,13 @@ execute_server(struct sc_server *server,
     if (params->camera_size) {
         ADD_PARAM("camera_size=%s", params->camera_size);
     }
+    if (params->camera_facing != SC_CAMERA_FACING_ANY) {
+        ADD_PARAM("camera_facing=%s",
+            sc_server_get_camera_facing_name(params->camera_facing));
+    }
+    if (params->camera_ar) {
+        ADD_PARAM("camera_ar=%s", params->camera_ar);
+    }
     if (params->show_touches) {
         ADD_PARAM("show_touches=true");
     }

app/src/server.h

@@ -28,6 +28,7 @@ struct sc_server_params {
     enum sc_codec audio_codec;
     enum sc_video_source video_source;
     enum sc_audio_source audio_source;
+    enum sc_camera_facing camera_facing;
     const char *crop;
     const char *video_codec_options;
     const char *audio_codec_options;
@@ -35,6 +36,7 @@ struct sc_server_params {
     const char *audio_encoder;
     const char *camera_id;
     const char *camera_size;
+    const char *camera_ar;
     struct sc_port_range port_range;
     uint32_t tunnel_host;
     uint16_t tunnel_port;

app/src/usb/hid_keyboard.c

@@ -27,7 +27,8 @@
 // keyboard support, though OS could support more keys via modifying the report
 // desc. 6 should be enough for scrcpy.
 #define HID_KEYBOARD_MAX_KEYS 6
-#define HID_KEYBOARD_EVENT_SIZE (2 + HID_KEYBOARD_MAX_KEYS)
+#define HID_KEYBOARD_EVENT_SIZE \
+    (HID_KEYBOARD_INDEX_KEYS + HID_KEYBOARD_MAX_KEYS)
 
 #define HID_RESERVED 0x00
 #define HID_ERROR_ROLL_OVER 0x01

app/tests/test_str.c

@@ -269,21 +269,25 @@ static void test_parse_integer_with_suffix(void) {
 
     char buf[32];
 
-    sprintf(buf, "%ldk", LONG_MAX / 2000);
+    int r = snprintf(buf, sizeof(buf), "%ldk", LONG_MAX / 2000);
+    assert(r >= 0 && (size_t) r < sizeof(buf));
     ok = sc_str_parse_integer_with_suffix(buf, &value);
     assert(ok);
     assert(value == LONG_MAX / 2000 * 1000);
 
-    sprintf(buf, "%ldm", LONG_MAX / 2000);
+    r = snprintf(buf, sizeof(buf), "%ldm", LONG_MAX / 2000);
+    assert(r >= 0 && (size_t) r < sizeof(buf));
     ok = sc_str_parse_integer_with_suffix(buf, &value);
     assert(!ok);
 
-    sprintf(buf, "%ldk", LONG_MIN / 2000);
+    r = snprintf(buf, sizeof(buf), "%ldk", LONG_MIN / 2000);
+    assert(r >= 0 && (size_t) r < sizeof(buf));
     ok = sc_str_parse_integer_with_suffix(buf, &value);
     assert(ok);
     assert(value == LONG_MIN / 2000 * 1000);
 
-    sprintf(buf, "%ldm", LONG_MIN / 2000);
+    r = snprintf(buf, sizeof(buf), "%ldm", LONG_MIN / 2000);
+    assert(r >= 0 && (size_t) r < sizeof(buf));
     ok = sc_str_parse_integer_with_suffix(buf, &value);
     assert(!ok);
 }

doc/video.md

@@ -143,7 +143,7 @@ If several displays are available on the Android device, it is possible to
 select the display to mirror:
 
 ```bash
-scrcpy --display=1
+scrcpy --display-id=1
 ```
 
 The list of display ids can be retrieved by:

server/src/main/java/com/genymobile/scrcpy/CameraAspectRatio.java

@@ -0,0 +1,37 @@
+package com.genymobile.scrcpy;
+
+public final class CameraAspectRatio {
+    private static final float SENSOR = -1;
+
+    private float ar;
+
+    private CameraAspectRatio(float ar) {
+        this.ar = ar;
+    }
+
+    public static CameraAspectRatio fromFloat(float ar) {
+        if (ar < 0) {
+            throw new IllegalArgumentException("Invalid aspect ratio: " + ar);
+        }
+        return new CameraAspectRatio(ar);
+    }
+
+    public static CameraAspectRatio fromFraction(int w, int h) {
+        if (w <= 0 || h <= 0) {
+            throw new IllegalArgumentException("Invalid aspect ratio: " + w + ":" + h);
+        }
+        return new CameraAspectRatio((float) w / h);
+    }
+
+    public static CameraAspectRatio sensorAspectRatio() {
+        return new CameraAspectRatio(SENSOR);
+    }
+
+    public boolean isSensor() {
+        return ar == SENSOR;
+    }
+
+    public float getAspectRatio() {
+        return ar;
+    }
+}

server/src/main/java/com/genymobile/scrcpy/CameraCapture.java

@@ -4,13 +4,18 @@ import com.genymobile.scrcpy.wrappers.ServiceManager;
 
 import android.annotation.SuppressLint;
 import android.annotation.TargetApi;
+import android.graphics.Rect;
 import android.hardware.camera2.CameraAccessException;
 import android.hardware.camera2.CameraCaptureSession;
+import android.hardware.camera2.CameraCharacteristics;
 import android.hardware.camera2.CameraDevice;
+import android.hardware.camera2.CameraManager;
 import android.hardware.camera2.CaptureFailure;
 import android.hardware.camera2.CaptureRequest;
 import android.hardware.camera2.params.OutputConfiguration;
 import android.hardware.camera2.params.SessionConfiguration;
+import android.hardware.camera2.params.StreamConfigurationMap;
+import android.media.MediaCodec;
 import android.os.Build;
 import android.os.Handler;
 import android.os.HandlerThread;
@@ -18,16 +23,25 @@ import android.view.Surface;
 
 import java.io.IOException;
 import java.util.Arrays;
+import java.util.Comparator;
 import java.util.List;
+import java.util.Optional;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Executor;
 import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.stream.Stream;
 
 public class CameraCapture extends SurfaceCapture {
 
-    private final String cameraId;
+    private final String explicitCameraId;
+    private final CameraFacing cameraFacing;
     private final Size explicitSize;
+    private int maxSize;
+    private final CameraAspectRatio aspectRatio;
+
+    private String cameraId;
+    private Size size;
 
     private HandlerThread cameraThread;
     private Handler cameraHandler;
@@ -36,9 +50,12 @@ public class CameraCapture extends SurfaceCapture {
 
     private final AtomicBoolean disconnected = new AtomicBoolean();
 
-    public CameraCapture(String cameraId, Size explicitSize) {
-        this.cameraId = cameraId;
+    public CameraCapture(String explicitCameraId, CameraFacing cameraFacing, Size explicitSize, int maxSize, CameraAspectRatio aspectRatio) {
+        this.explicitCameraId = explicitCameraId;
+        this.cameraFacing = cameraFacing;
         this.explicitSize = explicitSize;
+        this.maxSize = maxSize;
+        this.aspectRatio = aspectRatio;
     }
 
     @Override
@@ -49,12 +66,122 @@ public class CameraCapture extends SurfaceCapture {
         cameraExecutor = new HandlerExecutor(cameraHandler);
 
         try {
+            cameraId = selectCamera(explicitCameraId, cameraFacing);
+            if (cameraId == null) {
+                throw new IOException("No matching camera found");
+            }
+
+            size = selectSize(cameraId, explicitSize, maxSize, aspectRatio);
+            if (size == null) {
+                throw new IOException("Could not select camera size");
+            }
+
+            Ln.i("Using camera '" + cameraId + "'");
             cameraDevice = openCamera(cameraId);
         } catch (CameraAccessException | InterruptedException e) {
             throw new IOException(e);
         }
     }
 
+    private static String selectCamera(String explicitCameraId, CameraFacing cameraFacing) throws CameraAccessException {
+        if (explicitCameraId != null) {
+            return explicitCameraId;
+        }
+
+        CameraManager cameraManager = ServiceManager.getCameraManager();
+
+        String[] cameraIds = cameraManager.getCameraIdList();
+        if (cameraFacing == null) {
+            // Use the first one
+            return cameraIds.length > 0 ? cameraIds[0] : null;
+        }
+
+        for (String cameraId : cameraIds) {
+            CameraCharacteristics characteristics = cameraManager.getCameraCharacteristics(cameraId);
+
+            int facing = characteristics.get(CameraCharacteristics.LENS_FACING);
+            if (cameraFacing.value() == facing) {
+                return cameraId;
+            }
+        }
+
+        // Not found
+        return null;
+    }
+
+    @TargetApi(Build.VERSION_CODES.N)
+    private static Size selectSize(String cameraId, Size explicitSize, int maxSize, CameraAspectRatio aspectRatio) throws CameraAccessException {
+        if (explicitSize != null) {
+            return explicitSize;
+        }
+
+        CameraManager cameraManager = ServiceManager.getCameraManager();
+        CameraCharacteristics characteristics = cameraManager.getCameraCharacteristics(cameraId);
+
+        StreamConfigurationMap configs = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
+        android.util.Size[] sizes = configs.getOutputSizes(MediaCodec.class);
+        Stream<android.util.Size> stream = Arrays.stream(sizes);
+        if (maxSize > 0) {
+            stream = stream.filter(it -> it.getWidth() <= maxSize && it.getHeight() <= maxSize);
+        }
+
+        Float targetAspectRatio = resolveAspectRatio(aspectRatio, characteristics);
+        if (targetAspectRatio != null) {
+            stream = stream.filter(it -> {
+                float ar = ((float) it.getWidth() / it.getHeight());
+                float arRatio = ar / targetAspectRatio;
+                // Accept if the aspect ratio is the target aspect ratio + or - 10%
+                return arRatio >= 0.9f && arRatio <= 1.1f;
+            });
+        }
+
+        Optional<android.util.Size> selected = stream.max((s1, s2) -> {
+            // Greater width is better
+            int cmp = Integer.compare(s1.getWidth(), s2.getWidth());
+            if (cmp != 0) {
+                return cmp;
+            }
+
+            if (targetAspectRatio != null) {
+                // Closer to the target aspect ratio is better
+                float ar1 = ((float) s1.getWidth() / s1.getHeight());
+                float arRatio1 = ar1 / targetAspectRatio;
+                float distance1 = Math.abs(1 - arRatio1);
+
+                float ar2 = ((float) s2.getWidth() / s2.getHeight());
+                float arRatio2 = ar2 / targetAspectRatio;
+                float distance2 = Math.abs(1 - arRatio2);
+
+                // Reverse the order because lower distance is better
+                return Float.compare(distance2, distance1);
+            }
+
+            // Greater height is better
+            return Integer.compare(s1.getHeight(), s2.getHeight());
+        });
+
+        if (selected.isPresent()) {
+            android.util.Size size = selected.get();
+            return new Size(size.getWidth(), size.getHeight());
+        }
+
+        // Not found
+        return null;
+    }
+
+    private static Float resolveAspectRatio(CameraAspectRatio ratio, CameraCharacteristics characteristics) {
+        if (ratio == null) {
+            return null;
+        }
+
+        if (ratio.isSensor()) {
+            Rect activeSize = characteristics.get(CameraCharacteristics.SENSOR_INFO_ACTIVE_ARRAY_SIZE);
+            return (float) activeSize.width() / activeSize.height();
+        }
+
+        return ratio.getAspectRatio();
+    }
+
     @Override
     public void start(Surface surface) throws IOException {
         try {
@@ -80,24 +207,33 @@ public class CameraCapture extends SurfaceCapture {
 
     @Override
     public Size getSize() {
-        return explicitSize;
+        return size;
     }
 
     @Override
-    public boolean setMaxSize(int size) {
-        return false;
+    public boolean setMaxSize(int maxSize) {
+        if (explicitSize != null) {
+            return false;
+        }
+
+        this.maxSize = maxSize;
+        try {
+            size = selectSize(cameraId, null, maxSize, aspectRatio);
+            return true;
+        } catch (CameraAccessException e) {
+            Ln.w("Could not select camera size", e);
+            return false;
+        }
     }
 
     @SuppressLint("MissingPermission")
     @TargetApi(Build.VERSION_CODES.S)
     private CameraDevice openCamera(String id) throws CameraAccessException, InterruptedException {
-        Ln.v("Open Camera: " + id);
-
         CompletableFuture<CameraDevice> future = new CompletableFuture<>();
         ServiceManager.getCameraManager().openCamera(id, new CameraDevice.StateCallback() {
             @Override
             public void onOpened(CameraDevice camera) {
-                Ln.v("Open Camera Success");
+                Ln.d("Camera opened successfully");
                 future.complete(camera);
             }
 
@@ -140,17 +276,13 @@ public class CameraCapture extends SurfaceCapture {
 
     @TargetApi(Build.VERSION_CODES.S)
     private CameraCaptureSession createCaptureSession(CameraDevice camera, Surface surface) throws CameraAccessException, InterruptedException {
-        Ln.d("Create Capture Session");
-
         CompletableFuture<CameraCaptureSession> future = new CompletableFuture<>();
-        // replace by createCaptureSession(SessionConfiguration)
         OutputConfiguration outputConfig = new OutputConfiguration(surface);
         List<OutputConfiguration> outputs = Arrays.asList(outputConfig);
         SessionConfiguration sessionConfig = new SessionConfiguration(SessionConfiguration.SESSION_REGULAR, outputs, cameraExecutor,
                 new CameraCaptureSession.StateCallback() {
                     @Override
                     public void onConfigured(CameraCaptureSession session) {
-                        Ln.d("Create Capture Session Success");
                         future.complete(session);
                     }
 
@@ -195,4 +327,4 @@ public class CameraCapture extends SurfaceCapture {
     public boolean isClosed() {
         return disconnected.get();
     }
-}
+}

server/src/main/java/com/genymobile/scrcpy/CameraFacing.java

@@ -0,0 +1,31 @@
+package com.genymobile.scrcpy;
+
+import android.hardware.camera2.CameraCharacteristics;
+
+public enum CameraFacing {
+    FRONT("front", CameraCharacteristics.LENS_FACING_FRONT),
+    BACK("back", CameraCharacteristics.LENS_FACING_BACK),
+    EXTERNAL("external", CameraCharacteristics.LENS_FACING_EXTERNAL);
+
+    private final String name;
+    private final int value;
+
+    CameraFacing(String name, int value) {
+        this.name = name;
+        this.value = value;
+    }
+
+    int value() {
+        return value;
+    }
+
+    static CameraFacing findByName(String name) {
+        for (CameraFacing facing : CameraFacing.values()) {
+            if (name.equals(facing.name)) {
+                return facing;
+            }
+        }
+
+        return null;
+    }
+}

server/src/main/java/com/genymobile/scrcpy/LogUtils.java

@@ -54,7 +54,7 @@ public final class LogUtils {
             builder.append("\n    (none)");
         } else {
             for (int id : displayIds) {
-                builder.append("\n    --display=").append(id).append("    (");
+                builder.append("\n    --display-id=").append(id).append("    (");
                 DisplayInfo displayInfo = displayManager.getDisplayInfo(id);
                 if (displayInfo != null) {
                     Size size = displayInfo.getSize();
@@ -90,7 +90,7 @@ public final class LogUtils {
                 builder.append("\n    (none)");
             } else {
                 for (String id : cameraIds) {
-                    builder.append("\n    --video-source=camera --camera=").append(id);
+                    builder.append("\n    --video-source=camera --camera-id=").append(id);
                     CameraCharacteristics characteristics = cameraManager.getCameraCharacteristics(id);
                     int facing = characteristics.get(CameraCharacteristics.LENS_FACING);
                     builder.append("    (").append(getCameraFacingName(facing)).append(", ");

server/src/main/java/com/genymobile/scrcpy/Options.java

@@ -26,6 +26,8 @@ public class Options {
     private int displayId;
     private String cameraId;
     private Size cameraSize;
+    private CameraFacing cameraFacing;
+    private CameraAspectRatio cameraAspectRatio;
     private boolean showTouches;
     private boolean stayAwake;
     private List<CodecOption> videoCodecOptions;
@@ -126,6 +128,14 @@ public class Options {
         return cameraSize;
     }
 
+    public CameraFacing getCameraFacing() {
+        return cameraFacing;
+    }
+
+    public CameraAspectRatio getCameraAspectRatio() {
+        return cameraAspectRatio;
+    }
+
     public boolean getShowTouches() {
         return showTouches;
     }
@@ -292,7 +302,9 @@ public class Options {
                     options.tunnelForward = Boolean.parseBoolean(value);
                     break;
                 case "crop":
-                    options.crop = parseCrop(value);
+                    if (!value.isEmpty()) {
+                        options.crop = parseCrop(value);
+                    }
                     break;
                 case "control":
                     options.control = Boolean.parseBoolean(value);
@@ -349,10 +361,28 @@ public class Options {
                     options.listCameraSizes = Boolean.parseBoolean(value);
                     break;
                 case "camera_id":
-                    options.cameraId = value;
+                    if (!value.isEmpty()) {
+                        options.cameraId = value;
+                    }
                     break;
                 case "camera_size":
-                    options.cameraSize = parseSize(value);
+                    if (!value.isEmpty()) {
+                        options.cameraSize = parseSize(value);
+                    }
+                    break;
+                case "camera_facing":
+                    if (!value.isEmpty()) {
+                        CameraFacing facing = CameraFacing.findByName(value);
+                        if (facing == null) {
+                            throw new IllegalArgumentException("Camera facing " + value + " not supported");
+                        }
+                        options.cameraFacing = facing;
+                    }
+                    break;
+                case "camera_ar":
+                    if (!value.isEmpty()) {
+                        options.cameraAspectRatio = parseCameraAspectRatio(value);
+                    }
                     break;
                 case "send_device_meta":
                     options.sendDeviceMeta = Boolean.parseBoolean(value);
@@ -385,9 +415,6 @@ public class Options {
     }
 
     private static Rect parseCrop(String crop) {
-        if (crop.isEmpty()) {
-            return null;
-        }
         // input format: "width:height:x:y"
         String[] tokens = crop.split(":");
         if (tokens.length != 4) {
@@ -401,9 +428,6 @@ public class Options {
     }
 
     private static Size parseSize(String size) {
-        if (size.isEmpty()) {
-            return null;
-        }
         // input format: "<width>x<height>"
         String[] tokens = size.split("x");
         if (tokens.length != 2) {
@@ -413,4 +437,20 @@ public class Options {
         int height = Integer.parseInt(tokens[1]);
         return new Size(width, height);
     }
+
+    private static CameraAspectRatio parseCameraAspectRatio(String ar) {
+        if ("sensor".equals(ar)) {
+            return CameraAspectRatio.sensorAspectRatio();
+        }
+
+        String[] tokens = ar.split(":");
+        if (tokens.length == 2) {
+            int w = Integer.parseInt(tokens[0]);
+            int h = Integer.parseInt(tokens[1]);
+            return CameraAspectRatio.fromFraction(w, h);
+        }
+
+        float floatAr = Float.parseFloat(tokens[0]);
+        return CameraAspectRatio.fromFloat(floatAr);
+    }
 }

server/src/main/java/com/genymobile/scrcpy/Server.java

@@ -2,7 +2,6 @@ package com.genymobile.scrcpy;
 
 import android.os.BatteryManager;
 import android.os.Build;
-import android.os.Looper;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -89,6 +88,12 @@ public final class Server {
 
     private static void scrcpy(Options options) throws IOException, ConfigurationException {
         Ln.i("Device: [" + Build.MANUFACTURER + "] " + Build.BRAND + " " + Build.MODEL + " (Android " + Build.VERSION.RELEASE + ")");
+
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.S && options.getVideoSource() == VideoSource.CAMERA) {
+            Ln.e("Camera mirroring is not supported before Android 12");
+            throw new ConfigurationException("Camera mirroring is not supported");
+        }
+
         final Device device = new Device(options);
 
         Thread initThread = startInitThread(options);
@@ -138,7 +143,8 @@ public final class Server {
                 if (options.getVideoSource() == VideoSource.DISPLAY) {
                     surfaceCapture = new ScreenCapture(device);
                 } else {
-                    surfaceCapture = new CameraCapture(options.getCameraId(), options.getCameraSize());
+                    surfaceCapture = new CameraCapture(options.getCameraId(), options.getCameraFacing(), options.getCameraSize(),
+                            options.getMaxSize(), options.getCameraAspectRatio());
                 }
                 SurfaceEncoder surfaceEncoder = new SurfaceEncoder(surfaceCapture, videoStreamer, options.getVideoBitRate(), options.getMaxFps(),
                         options.getVideoCodecOptions(), options.getVideoEncoder(), options.getDownsizeOnError());

server/src/main/java/com/genymobile/scrcpy/VideoSource.java

@@ -1,7 +1,5 @@
 package com.genymobile.scrcpy;
 
-import android.media.MediaRecorder;
-
 public enum VideoSource {
     DISPLAY("display"),
     CAMERA("camera");

server/src/main/java/com/genymobile/scrcpy/Workarounds.java

@@ -32,7 +32,7 @@ public final class Workarounds {
         Workarounds.prepareMainLooper();
 
         boolean mustFillAppInfo = false;
-        boolean mustFillBaseContext = true;
+        boolean mustFillBaseContext = false;
         boolean mustFillAppContext = false;
 
         if (Build.BRAND.equalsIgnoreCase("meizu")) {
@@ -66,6 +66,7 @@ public final class Workarounds {
 
         if (camera) {
             mustFillAppInfo = true;
+            mustFillBaseContext = true;
         }
 
         if (mustFillAppInfo) {

server/src/main/java/com/genymobile/scrcpy/wrappers/ServiceManager.java

@@ -1,7 +1,6 @@
 package com.genymobile.scrcpy.wrappers;
 
 import com.genymobile.scrcpy.FakeContext;
-import com.genymobile.scrcpy.Workarounds;
 
 import android.annotation.SuppressLint;
 import android.content.Context;