Mention exclusive_caps mode in v4l2 documentation

PR #4435 <https://github.com/Genymobile/scrcpy/pull/4435>

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

doc/camera.md

@@ -18,6 +18,17 @@ scrcpy --video-source=display --audio-source=mic    # force display AND micropho
 scrcpy --video-source=camera --audio-source=output  # force camera AND device audio output
 ```
 
+Audio can be disabled:
+
+```bash
+# audio not captured at all
+scrcpy --video-source=camera --no-audio
+scrcpy --video-source=camera --no-audio --record=file.mp4
+
+# audio captured and recorded, but not played
+scrcpy --video-source=camera --no-audio-playback --record=file.mp4
+```
+
 
 ## List
 

doc/v4l2.md

@@ -21,6 +21,13 @@ This will create a new video device in `/dev/videoN`, where `N` is an integer
 (more [options](https://github.com/umlaeute/v4l2loopback#options) are available
 to create several devices or devices with specific IDs).
 
+If you encounter problems detecting your device with Chrome/WebRTC, you can try
+`exclusive_caps` mode:
+
+```
+sudo modprobe v4l2loopback exclusive_caps=1
+```
+
 To list the enabled devices:
 
 ```bash

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

@@ -2,12 +2,11 @@ package com.genymobile.scrcpy;
 
 import android.annotation.TargetApi;
 import android.content.AttributionSource;
-import android.content.Context;
+import android.content.MutableContextWrapper;
-import android.content.ContextWrapper;
 import android.os.Build;
 import android.os.Process;
 
-public final class FakeContext extends ContextWrapper {
+public final class FakeContext extends MutableContextWrapper {
 
     public static final String PACKAGE_NAME = "com.android.shell";
     public static final int ROOT_UID = 0; // Like android.os.Process.ROOT_UID, but before API 29
@@ -19,7 +18,7 @@ public final class FakeContext extends ContextWrapper {
     }
 
     private FakeContext() {
-        super(Workarounds.getSystemContext());
+        super(null);
     }
 
     @Override
@@ -45,9 +44,4 @@ public final class FakeContext extends ContextWrapper {
     public int getDeviceId() {
         return 0;
     }
-
-    @Override
-    public Context getApplicationContext() {
-        return this;
-    }
 }

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

@@ -3,17 +3,14 @@ package com.genymobile.scrcpy;
 import com.genymobile.scrcpy.wrappers.DisplayManager;
 import com.genymobile.scrcpy.wrappers.ServiceManager;
 
-import android.annotation.TargetApi;
 import android.graphics.Rect;
 import android.hardware.camera2.CameraAccessException;
 import android.hardware.camera2.CameraCharacteristics;
 import android.hardware.camera2.CameraManager;
 import android.hardware.camera2.params.StreamConfigurationMap;
 import android.media.MediaCodec;
-import android.os.Build;
 import android.util.Range;
 
-import java.util.Arrays;
 import java.util.List;
 import java.util.SortedSet;
 import java.util.TreeSet;
@@ -87,7 +84,6 @@ public final class LogUtils {
         }
     }
 
-    @TargetApi(Build.VERSION_CODES.P)
     public static String buildCameraListMessage(boolean includeSizes) {
         StringBuilder builder = new StringBuilder("List of cameras:");
         CameraManager cameraManager = ServiceManager.getCameraManager();
@@ -97,7 +93,7 @@ public final class LogUtils {
                 builder.append("\n    (none)");
             } else {
                 for (String id : cameraIds) {
-                    builder.append("\n    --camera-id=").append(id);
+                    builder.append("\n    --video-source=camera --camera-id=").append(id);
                     CameraCharacteristics characteristics = cameraManager.getCameraCharacteristics(id);
 
                     int facing = characteristics.get(CameraCharacteristics.LENS_FACING);
@@ -111,15 +107,6 @@ public final class LogUtils {
                     SortedSet<Integer> uniqueLowFps = getUniqueSet(lowFpsRanges);
                     builder.append("fps=").append(uniqueLowFps).append(')');
 
-                    int[] capabilities = characteristics.get(CameraCharacteristics.REQUEST_AVAILABLE_CAPABILITIES);
-                    if (Arrays.asList(capabilities).contains(CameraCharacteristics.REQUEST_AVAILABLE_CAPABILITIES_LOGICAL_MULTI_CAMERA)) {
-                        builder.append("\n        Logical multi-camera, backed by physical cameras:");
-                        for (String phyId : characteristics.getPhysicalCameraIds()) {
-                            CameraCharacteristics phyCharacteristics = cameraManager.getCameraCharacteristics(phyId);
-                            appendPhysicalCamera(builder, phyId, phyCharacteristics);
-                        }
-                    }
-
                     if (includeSizes) {
                         StreamConfigurationMap configs = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
 
@@ -147,13 +134,6 @@ public final class LogUtils {
         return builder.toString();
     }
 
-    private static void appendPhysicalCamera(StringBuilder builder, String id, CameraCharacteristics characteristics) {
-        builder.append("\n            --camera-id=").append(id).append("    (");
-
-        Rect activeSize = characteristics.get(CameraCharacteristics.SENSOR_INFO_ACTIVE_ARRAY_SIZE);
-        builder.append(activeSize.width()).append("x").append(activeSize.height()).append(")");
-    }
-
     private static SortedSet<Integer> getUniqueSet(Range<Integer>[] ranges) {
         SortedSet<Integer> set = new TreeSet<>();
         for (Range<Integer> range : ranges) {

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

@@ -21,34 +21,18 @@ import java.lang.reflect.Method;
 
 public final class Workarounds {
 
-    private static final Class<?> ACTIVITY_THREAD_CLASS;
+    private static Class<?> activityThreadClass;
-    private static final Object ACTIVITY_THREAD;
+    private static Object activityThread;
-
-    static {
-        prepareMainLooper();
-
-        try {
-            // ActivityThread activityThread = new ActivityThread();
-            ACTIVITY_THREAD_CLASS = Class.forName("android.app.ActivityThread");
-            Constructor<?> activityThreadConstructor = ACTIVITY_THREAD_CLASS.getDeclaredConstructor();
-            activityThreadConstructor.setAccessible(true);
-            ACTIVITY_THREAD = activityThreadConstructor.newInstance();
-
-            // ActivityThread.sCurrentActivityThread = activityThread;
-            Field sCurrentActivityThreadField = ACTIVITY_THREAD_CLASS.getDeclaredField("sCurrentActivityThread");
-            sCurrentActivityThreadField.setAccessible(true);
-            sCurrentActivityThreadField.set(null, ACTIVITY_THREAD);
-        } catch (Exception e) {
-            throw new AssertionError(e);
-        }
-    }
 
     private Workarounds() {
         // not instantiable
     }
 
     public static void apply(boolean audio, boolean camera) {
+        Workarounds.prepareMainLooper();
+
         boolean mustFillAppInfo = false;
+        boolean mustFillBaseContext = false;
         boolean mustFillAppContext = false;
 
         if (Build.BRAND.equalsIgnoreCase("meizu")) {
@@ -69,6 +53,7 @@ public final class Workarounds {
             //  - <https://github.com/Genymobile/scrcpy/issues/4015#issuecomment-1595382142>
             //  - <https://github.com/Genymobile/scrcpy/issues/3805#issuecomment-1596148031>
             mustFillAppInfo = true;
+            mustFillBaseContext = true;
             mustFillAppContext = true;
         }
 
@@ -81,12 +66,15 @@ public final class Workarounds {
 
         if (camera) {
             mustFillAppInfo = true;
-            mustFillAppContext = true;
+            mustFillBaseContext = true;
         }
 
         if (mustFillAppInfo) {
             Workarounds.fillAppInfo();
         }
+        if (mustFillBaseContext) {
+            Workarounds.fillBaseContext();
+        }
         if (mustFillAppContext) {
             Workarounds.fillAppContext();
         }
@@ -105,9 +93,27 @@ public final class Workarounds {
         Looper.prepareMainLooper();
     }
 
+    @SuppressLint("PrivateApi,DiscouragedPrivateApi")
+    private static void fillActivityThread() throws Exception {
+        if (activityThread == null) {
+            // ActivityThread activityThread = new ActivityThread();
+            activityThreadClass = Class.forName("android.app.ActivityThread");
+            Constructor<?> activityThreadConstructor = activityThreadClass.getDeclaredConstructor();
+            activityThreadConstructor.setAccessible(true);
+            activityThread = activityThreadConstructor.newInstance();
+
+            // ActivityThread.sCurrentActivityThread = activityThread;
+            Field sCurrentActivityThreadField = activityThreadClass.getDeclaredField("sCurrentActivityThread");
+            sCurrentActivityThreadField.setAccessible(true);
+            sCurrentActivityThreadField.set(null, activityThread);
+        }
+    }
+
     @SuppressLint("PrivateApi,DiscouragedPrivateApi")
     private static void fillAppInfo() {
         try {
+            fillActivityThread();
+
             // ActivityThread.AppBindData appBindData = new ActivityThread.AppBindData();
             Class<?> appBindDataClass = Class.forName("android.app.ActivityThread$AppBindData");
             Constructor<?> appBindDataConstructor = appBindDataClass.getDeclaredConstructor();
@@ -123,9 +129,9 @@ public final class Workarounds {
             appInfoField.set(appBindData, applicationInfo);
 
             // activityThread.mBoundApplication = appBindData;
-            Field mBoundApplicationField = ACTIVITY_THREAD_CLASS.getDeclaredField("mBoundApplication");
+            Field mBoundApplicationField = activityThreadClass.getDeclaredField("mBoundApplication");
             mBoundApplicationField.setAccessible(true);
-            mBoundApplicationField.set(ACTIVITY_THREAD, appBindData);
+            mBoundApplicationField.set(activityThread, appBindData);
         } catch (Throwable throwable) {
             // this is a workaround, so failing is not an error
             Ln.d("Could not fill app info: " + throwable.getMessage());
@@ -135,29 +141,33 @@ public final class Workarounds {
     @SuppressLint("PrivateApi,DiscouragedPrivateApi")
     private static void fillAppContext() {
         try {
-            Application app = new Application();
+            fillActivityThread();
+
+            Application app = Application.class.newInstance();
             Field baseField = ContextWrapper.class.getDeclaredField("mBase");
             baseField.setAccessible(true);
             baseField.set(app, FakeContext.get());
 
             // activityThread.mInitialApplication = app;
-            Field mInitialApplicationField = ACTIVITY_THREAD_CLASS.getDeclaredField("mInitialApplication");
+            Field mInitialApplicationField = activityThreadClass.getDeclaredField("mInitialApplication");
             mInitialApplicationField.setAccessible(true);
-            mInitialApplicationField.set(ACTIVITY_THREAD, app);
+            mInitialApplicationField.set(activityThread, app);
         } catch (Throwable throwable) {
             // this is a workaround, so failing is not an error
             Ln.d("Could not fill app context: " + throwable.getMessage());
         }
     }
 
-    static Context getSystemContext() {
+    private static void fillBaseContext() {
         try {
-            Method getSystemContextMethod = ACTIVITY_THREAD_CLASS.getDeclaredMethod("getSystemContext");
+            fillActivityThread();
-            return (Context) getSystemContextMethod.invoke(ACTIVITY_THREAD);
+
+            Method getSystemContextMethod = activityThreadClass.getDeclaredMethod("getSystemContext");
+            Context context = (Context) getSystemContextMethod.invoke(activityThread);
+            FakeContext.get().setBaseContext(context);
         } catch (Throwable throwable) {
             // this is a workaround, so failing is not an error
-            Ln.d("Could not get system context: " + throwable.getMessage());
+            Ln.d("Could not fill base context: " + throwable.getMessage());
-            return null;
         }
     }