Support adding and removing MediaRecorder to camera 2 session.

webrtc/sdk/android/src/java/org/webrtc/CameraCapturer.java

Index: webrtc/sdk/android/src/java/org/webrtc/CameraCapturer.java
diff --git a/webrtc/sdk/android/src/java/org/webrtc/CameraCapturer.java b/webrtc/sdk/android/src/java/org/webrtc/CameraCapturer.java
index c3e8daab17cd857f8f5a968f0fdc86ab94c20e63..e19671f125d2b9550216d1b9bf5e18ecd76c2a79 100644
--- a/webrtc/sdk/android/src/java/org/webrtc/CameraCapturer.java
+++ b/webrtc/sdk/android/src/java/org/webrtc/CameraCapturer.java
@@ -11,6 +11,7 @@
 package org.webrtc;
 
 import android.content.Context;
+import android.media.MediaRecorder;
 import android.os.Handler;
 import android.os.Looper;
 import java.util.Arrays;
@@ -23,6 +24,11 @@ abstract class CameraCapturer implements CameraVideoCapturer {
     IN_PROGRESS, // Waiting for new switched capture session to start.
   }
 
+  enum MediaRecorderState {
+    IDLE, // No media recording update (add or remove) requested.
+    IN_PROGRESS, // Waiting for new capture session with updated MediaRecorder surface to start.
+  }
+
   private static final String TAG = "CameraCapturer";
   private final static int MAX_OPEN_CAMERA_ATTEMPTS = 3;
   private final static int OPEN_CAMERA_DELAY_MS = 500;
@@ -56,6 +62,13 @@ abstract class CameraCapturer implements CameraVideoCapturer {
             } else if (switchState == SwitchState.PENDING) {
               switchState = SwitchState.IDLE;
               switchCameraInternal(switchEventsHandler);
+            } else if (mediaRecorderState == MediaRecorderState.IN_PROGRESS) {

[sakal, 2017/04/21 08:06:15]

One more thing, this shouldn't be else if. switchState can become PENDING while
mediaRecorderState is IN_PROGRESS.

[AlexG, 2017/04/21 19:38:11]

Done.

+              if (mediaRecorderEventsHandler != null) {
+                mediaRecorderEventsHandler.onMediaRecorderSuccess();
+                mediaRecorderEventsHandler = null;
+              }
+              mediaRecorder = null;

[sakal, 2017/04/21 08:06:15]

Why is mediaRecorder set to null here? This means cameraSwitch will cause the
mediaRecorder to be removed. Is this intended?

[AlexG, 2017/04/21 19:38:11]

Yes, camera switch is not allowed while MediaRecorder is added to camera
pipeline. I will add double check to disallow camera switch to start when media
recording is in progress.

+              mediaRecorderState = MediaRecorderState.IDLE;
             }
           }
         }
@@ -80,6 +93,14 @@ abstract class CameraCapturer implements CameraVideoCapturer {
                 }
                 switchState = SwitchState.IDLE;
               }
+              if (mediaRecorderState == MediaRecorderState.IN_PROGRESS) {
+                if (mediaRecorderEventsHandler != null) {
+                  mediaRecorderEventsHandler.onMediaRecorderError(error);
+                  mediaRecorderEventsHandler = null;
+                }
+                mediaRecorder = null;
+                mediaRecorderState = MediaRecorderState.IDLE;
+              }
 
               if (failureType == CameraSession.FailureType.DISCONNECTED) {
                 eventsHandler.onCameraDisconnected();
@@ -198,6 +219,7 @@ abstract class CameraCapturer implements CameraVideoCapturer {
   private Context applicationContext;
   private CapturerObserver capturerObserver;
   private SurfaceTextureHelper surfaceHelper;
+  private MediaRecorder mediaRecorder;
 
   private final Object stateLock = new Object();
   private boolean sessionOpening; /* guarded by stateLock */
@@ -208,7 +230,10 @@ abstract class CameraCapturer implements CameraVideoCapturer {
   private int framerate; /* guarded by stateLock */
   private int openAttemptsRemaining; /* guarded by stateLock */
   private SwitchState switchState = SwitchState.IDLE; /* guarded by stateLock */
+  /* guarded by stateLock */
+  private MediaRecorderState mediaRecorderState = MediaRecorderState.IDLE;

[sakal, 2017/04/21 07:56:49]

Since these are only manipulated on the camera thread, I don't think a lock is
needed. Make a new section for variables only used on the camera thread.

[AlexG, 2017/04/21 19:38:11]

Done.

   private CameraSwitchHandler switchEventsHandler; /* guarded by stateLock */
+  private MediaRecorderHandler mediaRecorderEventsHandler; /* guarded by stateLock */
   // Valid from onDone call until stopCapture, otherwise null.
   private CameraStatistics cameraStatistics; /* guarded by stateLock */
   private boolean firstFrameObserved; /* guarded by stateLock */
@@ -287,7 +312,7 @@ abstract class CameraCapturer implements CameraVideoCapturer {
       @Override
       public void run() {
         createCameraSession(createSessionCallback, cameraSessionEventsHandler, applicationContext,
-            surfaceHelper, cameraName, width, height, framerate);
+            surfaceHelper, mediaRecorder, cameraName, width, height, framerate);
       }
     }, delayMs);
   }
@@ -350,6 +375,29 @@ abstract class CameraCapturer implements CameraVideoCapturer {
   }
 
   @Override
+  public void addMediaRecorderToCamera(
+      final MediaRecorder mediaRecorder, final MediaRecorderHandler mediaRecoderEventsHandler) {
+    Logging.d(TAG, "addMediaRecorderToCamera");
+    cameraThreadHandler.post(new Runnable() {
+      @Override
+      public void run() {
+        updateMediaRecorderInternal(mediaRecorder, mediaRecoderEventsHandler);
+      }
+    });
+  }
+
+  @Override
+  public void removeMediaRecorderFromCamera(final MediaRecorderHandler mediaRecoderEventsHandler) {
+    Logging.d(TAG, "removeMediaRecorderFromCamera");
+    cameraThreadHandler.post(new Runnable() {
+      @Override
+      public void run() {
+        updateMediaRecorderInternal(null /* mediaRecorder */, mediaRecoderEventsHandler);
+      }
+    });
+  }
+
+  @Override
   public boolean isScreencast() {
     return false;
   }
@@ -429,6 +477,60 @@ abstract class CameraCapturer implements CameraVideoCapturer {
     Logging.d(TAG, "switchCamera done");
   }
 
+  private void reportUpdateMediaRecorderError(
+      String error, MediaRecorderHandler mediaRecoderEventsHandler) {
+    Logging.e(TAG, error);

[sakal, 2017/04/21 07:56:49]

Please add checkIsOnCameraThread()

[AlexG, 2017/04/21 19:38:11]

Done.

+    if (mediaRecoderEventsHandler != null) {
+      mediaRecoderEventsHandler.onMediaRecorderError(error);
+    }
+  }
+
+  private void updateMediaRecorderInternal(
+      final MediaRecorder mediaRecorder, final MediaRecorderHandler mediaRecoderEventsHandler) {
+    Logging.d(TAG,

[sakal, 2017/04/21 07:56:49]

Please add checkIsOnCameraThread()

[AlexG, 2017/04/21 19:38:11]

Done.

+        "updateMediaRecoderInternal internal. State: " + mediaRecorderState
+            + ". Session opening: " + sessionOpening);
+
+    synchronized (stateLock) {
+      if (mediaRecorderState != MediaRecorderState.IDLE) {
+        reportUpdateMediaRecorderError(
+            "MediaRecorder update already in progress.", mediaRecoderEventsHandler);
+        return;
+      }
+      if (switchState != SwitchState.IDLE) {
+        reportUpdateMediaRecorderError(
+            "MediaRecorder update while camera is switching.", mediaRecoderEventsHandler);
+        return;
+      }
+      if (sessionOpening) {
+        reportUpdateMediaRecorderError(
+            "MediaRecorder update while camera is still opening.", mediaRecoderEventsHandler);
+        return;
+      }
+
+      this.mediaRecorder = mediaRecorder;
+      this.mediaRecorderEventsHandler = mediaRecoderEventsHandler;
+      mediaRecorderState = MediaRecorderState.IN_PROGRESS;
+
+      Logging.d(TAG, "updateMediaRecoder: Stopping session");
+      cameraStatistics.release();
+      cameraStatistics = null;
+      final CameraSession oldSession = currentSession;
+      cameraThreadHandler.post(new Runnable() {
+        @Override
+        public void run() {
+          oldSession.stop();
+        }
+      });
+      currentSession = null;
+
+      sessionOpening = true;
+      openAttemptsRemaining = 1;
+      createSessionInternal(0);
+    }
+    Logging.d(TAG, "updateMediaRecoderInternal done");
+  }
+
   private void checkIsOnCameraThread() {
     if (Thread.currentThread() != cameraThreadHandler.getLooper().getThread()) {
       Logging.e(TAG, "Check is on camera thread failed.");
@@ -444,6 +546,6 @@ abstract class CameraCapturer implements CameraVideoCapturer {
 
   abstract protected void createCameraSession(
       CameraSession.CreateSessionCallback createSessionCallback, CameraSession.Events events,
-      Context applicationContext, SurfaceTextureHelper surfaceTextureHelper, String cameraName,
-      int width, int height, int framerate);
+      Context applicationContext, SurfaceTextureHelper surfaceTextureHelper,
+      MediaRecorder mediaRecoder, String cameraName, int width, int height, int framerate);
 }