VideoCapturerAndroid: Add function to change capture format while camera is running

talk/app/webrtc/java/src/org/webrtc/VideoCapturerAndroid.java

Index: talk/app/webrtc/java/src/org/webrtc/VideoCapturerAndroid.java
diff --git a/talk/app/webrtc/java/src/org/webrtc/VideoCapturerAndroid.java b/talk/app/webrtc/java/src/org/webrtc/VideoCapturerAndroid.java
index e40cd1ac29cb9afac7eea536fa6681692f365d81..1d4e181d872e06aec5268ff900dcf879b6601eb8 100644
--- a/talk/app/webrtc/java/src/org/webrtc/VideoCapturerAndroid.java
+++ b/talk/app/webrtc/java/src/org/webrtc/VideoCapturerAndroid.java
@@ -270,6 +270,18 @@ public class VideoCapturerAndroid extends VideoCapturer implements PreviewCallba
     return true;
   }
 
+  public List<CaptureFormat> getSupportedFormats() {
+    return supportedFormats.get(id);
+  }
+
+  public void changeCaptureFormat(final int width, final int height, final int framerate) {
+    cameraThreadHandler.post(new Runnable() {
+      @Override public void run() {
+        changeCaptureFormatOnCameraThread(width, height, framerate);
+      }
+    });
+  }
+
   private VideoCapturerAndroid() {
     Log.d(TAG, "VideoCapturerAndroid");
   }
@@ -334,7 +346,7 @@ public class VideoCapturerAndroid extends VideoCapturer implements PreviewCallba
     return getSupportedFormatsAsJson(id);
   }
 
-  static class CaptureFormat {
+  public static class CaptureFormat {
     public final int width;
     public final int height;
     public final int maxFramerate;
@@ -578,6 +590,26 @@ public class VideoCapturerAndroid extends VideoCapturer implements PreviewCallba
     return;
   }
 
+  private void changeCaptureFormatOnCameraThread(int width, int height, int framerate) {

[hbos, 2015/06/12 09:34:48]

What if the capturer is currently not running? Will this start capturing?
Possibly not properly initialized?

[magjed_webrtc, 2015/06/12 12:52:23]

Done. Added checks.

[hbos, 2015/06/15 07:42:12]

Add a comment to changeCaptureFormat that it can only be called whilst running
or else its a no-op.

[magjed_webrtc, 2015/06/17 10:47:57]

Done.

+    Log.d(TAG, "changeCaptureFormat requested: " + width + "x" + height + "@" + framerate);
+    this.width = width;
+    this.height = height;
+    this.framerate = framerate;
+    Camera.Parameters parameters = camera.getParameters();
+    int[] range = getFramerateRange(parameters, framerate * 1000);
+    if (range != null) {
+      parameters.setPreviewFpsRange(
+          range[Camera.Parameters.PREVIEW_FPS_MIN_INDEX],
+          range[Camera.Parameters.PREVIEW_FPS_MAX_INDEX]);
+    }
+    parameters.setPreviewSize(width, height);
+    camera.stopPreview();
+    camera.setParameters(parameters);
+    videoBuffers.queueCameraBuffers(width, height, ImageFormat.YV12, camera);
+    camera.setPreviewCallbackWithBuffer(this);
+    camera.startPreview();
+  }
+
   // Called by native code.  Returns true when camera is known to be stopped.
   synchronized void stopCapture() throws InterruptedException {
     if (cameraThreadHandler == null) {
@@ -716,7 +748,7 @@ public class VideoCapturerAndroid extends VideoCapturer implements PreviewCallba
     if (Thread.currentThread() != cameraThread) {
       throw new RuntimeException("Camera callback not on camera thread?!?");
     }
-    if (camera == null) {
+    if (camera == null || data == null) {
       return;
     }
     if (camera != callbackCamera) {
@@ -736,9 +768,12 @@ public class VideoCapturerAndroid extends VideoCapturer implements PreviewCallba
     // Mark the frame owning |data| as used.
     // Note that since data is directBuffer,
     // data.length >= videoBuffers.frameSize.
-    videoBuffers.reserveByteBuffer(data, captureTimeNs);
-    frameObserver.OnFrameCaptured(data, videoBuffers.frameSize, rotation,
-        captureTimeNs);
+    if (videoBuffers.reserveByteBuffer(data, captureTimeNs)) {
+      frameObserver.OnFrameCaptured(data, videoBuffers.frameSize,
+          width, height, rotation, captureTimeNs);
+    } else {
+      Log.w(TAG, "reserveByteBuffer failed - dropping frame");

[hbos, 2015/06/12 09:34:48]

cameraFramesCount-- or no?

[magjed_webrtc, 2015/06/12 12:52:23]

Done. Moved 'cameraFramesCount++' into the same scope as
frameObserver.OnFrameCaptured.

+    }
   }
 
   // runCameraThreadUntilIdle make sure all posted messages to the cameraThread
@@ -798,9 +833,7 @@ public class VideoCapturerAndroid extends VideoCapturer implements PreviewCallba
     // Adds frames as callback buffers to |camera|. If a new frame size is
     // required, new buffers are allocated and added.
     void queueCameraBuffers(int width, int height, int format, Camera camera) {
-      if (this.camera != null)
-        throw new RuntimeException("camera already set.");
-
+      boolean cameraWasNull = (this.camera == null);
       this.camera = camera;
       int newFrameSize = CaptureFormat.frameSize(width, height, format);
 
@@ -814,7 +847,7 @@ public class VideoCapturerAndroid extends VideoCapturer implements PreviewCallba
           this.camera.addCallbackBuffer(frame.data());
         }
         numCaptureBuffersAvailable = numCaptureBuffers;
-      } else {
+      } else if (cameraWasNull) {
         // Add all frames that have been returned.
         for (Frame frame : cameraFrames) {
           if (frame.timeStamp < 0) {
@@ -822,6 +855,8 @@ public class VideoCapturerAndroid extends VideoCapturer implements PreviewCallba
             numCaptureBuffersAvailable++;
           }
         }
+      } else {
+        // Same framesize and camera is still running - no need to do anything.
       }
       frameSize = newFrameSize;
       Log.d(TAG, "queueCameraBuffers enqued " + numCaptureBuffersAvailable
@@ -849,19 +884,24 @@ public class VideoCapturerAndroid extends VideoCapturer implements PreviewCallba
 
     }
 
-    void reserveByteBuffer(byte[] data, long timeStamp) {
+    boolean reserveByteBuffer(byte[] data, long timeStamp) {
       for (Frame frame : cameraFrames) {
         if (data == frame.data()) {
           if (frame.timeStamp > 0) {
             throw new RuntimeException("Frame already in use !");
           }
+          if (frame.frameSize != frameSize) {
+            Log.w(TAG, "Outdated framesize - removing byte buffer from pool");
+            cameraFrames.remove(frame);

[hbos, 2015/06/12 09:34:48]

Ought we not re-queueCameraBuffers or the equivalent? Could we start dropping
buffers and then run out of buffers?

[magjed_webrtc, 2015/06/12 12:52:23]

No, that shouldn't be possible. The function queueCameraBuffer is responsible
for (re)queuing buffers. If frameSize changes, we always add 
|numCaptureBuffersAvailable| new buffers.

+            return false;
+          }
           frame.timeStamp = timeStamp;
           numCaptureBuffersAvailable--;
           if (numCaptureBuffersAvailable == 0) {
             Log.v(TAG, "Camera is running out of capture buffers."
                 + " Pending buffers: [" + pendingFramesTimeStamps() + "]");
           }
-          return;
+          return true;
         }
       }
       throw new RuntimeException("unknown data buffer?!?");
@@ -917,8 +957,8 @@ public class VideoCapturerAndroid extends VideoCapturer implements PreviewCallba
 
     // Delivers a captured frame. Called on a Java thread owned by
     // VideoCapturerAndroid.
-    abstract void OnFrameCaptured(byte[] data, int length, int rotation,
-        long timeStamp);
+    abstract void OnFrameCaptured(byte[] data, int length, int width, int height,
+        int rotation, long timeStamp);
   }
 
   // An implementation of CapturerObserver that forwards all calls from
@@ -936,14 +976,14 @@ public class VideoCapturerAndroid extends VideoCapturer implements PreviewCallba
     }
 
     @Override
-    public void OnFrameCaptured(byte[] data, int length, int rotation,
-        long timeStamp) {
-      nativeOnFrameCaptured(nativeCapturer, data, length, rotation, timeStamp);
+    public void OnFrameCaptured(byte[] data, int length, int width, int height,
+        int rotation, long timeStamp) {
+      nativeOnFrameCaptured(nativeCapturer, data, length, width, height, rotation, timeStamp);
     }
 
     private native void nativeCapturerStarted(long nativeCapturer,
         boolean success);
     private native void nativeOnFrameCaptured(long nativeCapturer,
-        byte[] data, int length, int rotation, long timeStamp);
+        byte[] data, int length, int width, int height, int rotation, long timeStamp);
   }
 }