Actual Video recording callback (#498)

* added video recording callback
* updated test
* added annotation to dispatch function
* updated review comments for video recording callback
* reverted unwanted changes
* Add tests and changelog
* Fix video tests

cameraview/src/androidTest/java/com/otaliastudios/cameraview/CameraViewCallbacksTest.java

@@ -155,6 +155,15 @@ public class CameraViewCallbacksTest extends BaseTest {
         verify(listener, times(1)).onCameraClosed();
     }
 
+    @Test
+    public void testDispatchOnVideoRecordingStart() {
+        completeTask().when(listener).onVideoRecordingStart();
+        camera.mCameraCallbacks.dispatchOnVideoRecordingStart();
+
+        assertNotNull(op.await(500));
+        verify(listener, times(1)).onVideoRecordingStart();
+    }
+
     @Test
     public void testDispatchOnVideoTaken() {
         VideoResult.Stub stub = new VideoResult.Stub();

cameraview/src/androidTest/java/com/otaliastudios/cameraview/engine/CameraIntegrationTest.java

@@ -5,7 +5,6 @@ import android.graphics.Bitmap;
 import android.graphics.PointF;
 import android.hardware.Camera;
 import android.os.Build;
-import android.util.Log;
 
 import com.otaliastudios.cameraview.BaseTest;
 import com.otaliastudios.cameraview.CameraException;
@@ -13,7 +12,6 @@ import com.otaliastudios.cameraview.CameraListener;
 import com.otaliastudios.cameraview.CameraOptions;
 import com.otaliastudios.cameraview.CameraUtils;
 import com.otaliastudios.cameraview.CameraView;
-import com.otaliastudios.cameraview.DoNotRunOnTravis;
 import com.otaliastudios.cameraview.PictureResult;
 import com.otaliastudios.cameraview.TestActivity;
 import com.otaliastudios.cameraview.VideoResult;
@@ -30,19 +28,14 @@ import com.otaliastudios.cameraview.internal.utils.WorkerHandler;
 import com.otaliastudios.cameraview.size.Size;
 
 import androidx.annotation.NonNull;
-import androidx.test.ext.junit.runners.AndroidJUnit4;
+import androidx.annotation.Nullable;
-import androidx.test.filters.LargeTest;
-import androidx.test.filters.MediumTest;
-import androidx.test.filters.SmallTest;
 import androidx.test.rule.ActivityTestRule;
 
 import org.junit.After;
 import org.junit.Before;
 import org.junit.BeforeClass;
-import org.junit.Ignore;
 import org.junit.Rule;
 import org.junit.Test;
-import org.junit.runner.RunWith;
 import org.mockito.ArgumentMatcher;
 
 import java.io.File;
@@ -103,6 +96,8 @@ public abstract class CameraIntegrationTest extends BaseTest {
                 rule.getActivity().inflate(camera);
 
                 // Ensure that controller exceptions are thrown on this thread (not on the UI thread).
+                // TODO this makes debugging for wrong tests very hard, as we don't get the exception
+                // unless waitForUiException() is called.
                 uiExceptionOp = new Op<>(true);
                 WorkerHandler crashThread = WorkerHandler.get("CrashThread");
                 crashThread.getThread().setUncaughtExceptionHandler(new Thread.UncaughtExceptionHandler() {
@@ -130,7 +125,7 @@ public abstract class CameraIntegrationTest extends BaseTest {
         }
     }
 
-    private CameraOptions waitForOpen(boolean expectSuccess) {
+    private CameraOptions openSync(boolean expectSuccess) {
         camera.open();
         final Op<CameraOptions> open = new Op<>(true);
         doEndTask(open, 0).when(listener).onCameraOpened(any(CameraOptions.class));
@@ -145,7 +140,7 @@ public abstract class CameraIntegrationTest extends BaseTest {
         return result;
     }
 
-    private void waitForClose(boolean expectSuccess) {
+    private void closeSync(boolean expectSuccess) {
         camera.close();
         final Op<Boolean> close = new Op<>(true);
         doEndTask(close, true).when(listener).onCameraClosed();
@@ -157,25 +152,28 @@ public abstract class CameraIntegrationTest extends BaseTest {
         }
     }
 
-    private void waitForVideoEnd(boolean expectSuccess) {
+    @SuppressWarnings("UnusedReturnValue")
-        final Op<Boolean> video = new Op<>(true);
+    @Nullable
-        doEndTask(video, true).when(listener).onVideoTaken(any(VideoResult.class));
+    private VideoResult waitForVideoResult(boolean expectSuccess) {
-        doEndTask(video, false).when(listener).onCameraError(argThat(new ArgumentMatcher<CameraException>() {
+        final Op<VideoResult> video = new Op<>(true);
+        doEndTask(video, 0).when(listener).onVideoTaken(any(VideoResult.class));
+        doEndTask(video, null).when(listener).onCameraError(argThat(new ArgumentMatcher<CameraException>() {
             @Override
             public boolean matches(CameraException argument) {
                 return argument.getReason() == CameraException.REASON_VIDEO_FAILED;
             }
         }));
-        Boolean result = video.await(DELAY);
+        VideoResult result = video.await(DELAY);
         if (expectSuccess) {
             assertNotNull("Should end video", result);
-            assertTrue("Should end video without errors", result);
         } else {
             assertNull("Should not end video", result);
         }
+        return result;
     }
 
-    private PictureResult waitForPicture(boolean expectSuccess) {
+    @Nullable
+    private PictureResult waitForPictureResult(boolean expectSuccess) {
         final Op<PictureResult> pic = new Op<>(true);
         doEndTask(pic, 0).when(listener).onPictureTaken(any(PictureResult.class));
         doEndTask(pic, null).when(listener).onCameraError(argThat(new ArgumentMatcher<CameraException>() {
@@ -193,12 +191,60 @@ public abstract class CameraIntegrationTest extends BaseTest {
         return result;
     }
 
-    private void waitForVideoStart() {
+    private void takeVideoSync(boolean expectSuccess) {
-        controller.mStartVideoOp.listen();
+        takeVideoSync(expectSuccess,0);
+    }
+
+    private void takeVideoSync(boolean expectSuccess, int duration) {
+        final Op<Boolean> op = new Op<>(true);
+        doEndTask(op, true).when(listener).onVideoRecordingStart();
+        doEndTask(op, false).when(listener).onCameraError(argThat(new ArgumentMatcher<CameraException>() {
+            @Override
+            public boolean matches(CameraException argument) {
+                return argument.getReason() == CameraException.REASON_VIDEO_FAILED;
+            }
+        }));
+        File file = new File(context().getFilesDir(), "video.mp4");
+        if (duration > 0) {
+            camera.takeVideo(file, duration);
+        } else {
+            camera.takeVideo(file);
+        }
+        Boolean result = op.await(DELAY);
+        if (expectSuccess) {
+            assertNotNull("should start video recording or get CameraError", result);
+            assertTrue("should start video recording successfully", result);
+        } else {
+            assertTrue("should not start video recording", result == null || !result);
+        }
+    }
+
+    private void takeVideoSnapshotSync(boolean expectSuccess) {
+        takeVideoSnapshotSync(expectSuccess,0);
+    }
+
+    private void takeVideoSnapshotSync(boolean expectSuccess, int duration) {
+        final Op<Boolean> op = new Op<>(true);
+        doEndTask(op, true).when(listener).onVideoRecordingStart();
+        doEndTask(op, false).when(listener).onCameraError(argThat(new ArgumentMatcher<CameraException>() {
+            @Override
+            public boolean matches(CameraException argument) {
+                return argument.getReason() == CameraException.REASON_VIDEO_FAILED;
+            }
+        }));
         File file = new File(context().getFilesDir(), "video.mp4");
-        camera.takeVideo(file);
+        if (duration > 0) {
-        controller.mStartVideoOp.await(DELAY);
+            camera.takeVideoSnapshot(file, duration);
-        // TODO assert!
+        } else {
+            camera.takeVideoSnapshot(file);
+        }
+        Boolean result = op.await(DELAY);
+        if (expectSuccess) {
+            assertNotNull("should start video recording or get CameraError", result);
+            assertTrue("should start video recording successfully", result);
+        } else {
+            assertTrue("should not start video recording", result == null || !result);
+        }
     }
 
     //region test open/close
@@ -208,22 +254,22 @@ public abstract class CameraIntegrationTest extends BaseTest {
         // Starting and stopping are hard to get since they happen on another thread.
         assertEquals(controller.getEngineState(), CameraEngine.STATE_STOPPED);
 
-        waitForOpen(true);
+        openSync(true);
         assertEquals(controller.getEngineState(), CameraEngine.STATE_STARTED);
 
-        waitForClose(true);
+        closeSync(true);
         assertEquals(controller.getEngineState(), CameraEngine.STATE_STOPPED);
     }
 
     @Test
     public void testOpenTwice() {
-        waitForOpen(true);
+        openSync(true);
-        waitForOpen(false);
+        openSync(false);
     }
 
     @Test
     public void testCloseTwice() {
-        waitForClose(false);
+        closeSync(false);
     }
 
     @Test
@@ -247,7 +293,7 @@ public abstract class CameraIntegrationTest extends BaseTest {
     @Test
     public void testStartInitializesOptions() {
         assertNull(camera.getCameraOptions());
-        waitForOpen(true);
+        openSync(true);
         assertNotNull(camera.getCameraOptions());
     }
 
@@ -258,7 +304,7 @@ public abstract class CameraIntegrationTest extends BaseTest {
 
     @Test
     public void testSetFacing() throws Exception {
-        CameraOptions o = waitForOpen(true);
+        CameraOptions o = openSync(true);
         int size = o.getSupportedFacing().size();
         if (size > 1) {
             // set facing should call stop and start again.
@@ -276,7 +322,7 @@ public abstract class CameraIntegrationTest extends BaseTest {
     @Test
     public void testSetMode() throws Exception {
         camera.setMode(Mode.PICTURE);
-        waitForOpen(true);
+        openSync(true);
 
         // set session type should call stop and start again.
         final CountDownLatch latch = new CountDownLatch(2);
@@ -297,7 +343,7 @@ public abstract class CameraIntegrationTest extends BaseTest {
 
     @Test
     public void testSetZoom() {
-        CameraOptions options = waitForOpen(true);
+        CameraOptions options = openSync(true);
 
         controller.mZoomOp.listen();
         float oldValue = camera.getZoom();
@@ -314,7 +360,7 @@ public abstract class CameraIntegrationTest extends BaseTest {
 
     @Test
     public void testSetExposureCorrection() {
-        CameraOptions options = waitForOpen(true);
+        CameraOptions options = openSync(true);
 
         controller.mExposureCorrectionOp.listen();
         float oldValue = camera.getExposureCorrection();
@@ -331,7 +377,7 @@ public abstract class CameraIntegrationTest extends BaseTest {
 
     @Test
     public void testSetFlash() {
-        CameraOptions options = waitForOpen(true);
+        CameraOptions options = openSync(true);
         Flash[] values = Flash.values();
         Flash oldValue = camera.getFlash();
         for (Flash value : values) {
@@ -349,7 +395,7 @@ public abstract class CameraIntegrationTest extends BaseTest {
 
     @Test
     public void testSetWhiteBalance() {
-        CameraOptions options = waitForOpen(true);
+        CameraOptions options = openSync(true);
         WhiteBalance[] values = WhiteBalance.values();
         WhiteBalance oldValue = camera.getWhiteBalance();
         for (WhiteBalance value : values) {
@@ -367,7 +413,7 @@ public abstract class CameraIntegrationTest extends BaseTest {
 
     @Test
     public void testSetHdr() {
-        CameraOptions options = waitForOpen(true);
+        CameraOptions options = openSync(true);
         Hdr[] values = Hdr.values();
         Hdr oldValue = camera.getHdr();
         for (Hdr value : values) {
@@ -386,7 +432,7 @@ public abstract class CameraIntegrationTest extends BaseTest {
     @Test
     public void testSetAudio() {
         // TODO: when permissions are managed, check that Audio.ON triggers the audio permission
-        waitForOpen(true);
+        openSync(true);
         Audio[] values = Audio.values();
         for (Audio value : values) {
             camera.setAudio(value);
@@ -396,7 +442,7 @@ public abstract class CameraIntegrationTest extends BaseTest {
 
     @Test
     public void testSetLocation() {
-        waitForOpen(true);
+        openSync(true);
         controller.mLocationOp.listen();
         camera.setLocation(10d, 2d);
         controller.mLocationOp.await(300);
@@ -440,8 +486,8 @@ public abstract class CameraIntegrationTest extends BaseTest {
         // Error while starting MediaRecorder. java.lang.RuntimeException: start failed.
         // as documented. This works locally though.
         camera.setMode(Mode.PICTURE);
-        waitForOpen(true);
+        openSync(true);
-        waitForVideoStart();
+        takeVideoSync(false);
         waitForUiException();
     }
 
@@ -451,35 +497,35 @@ public abstract class CameraIntegrationTest extends BaseTest {
         // Error while starting MediaRecorder. java.lang.RuntimeException: start failed.
         // as documented. This works locally though.
         camera.setMode(Mode.VIDEO);
-        waitForOpen(true);
+        openSync(true);
-        camera.takeVideo(new File(context().getFilesDir(), "video.mp4"), 4000);
+        takeVideoSync(true, 4000);
-        waitForVideoEnd(true);
+        waitForVideoResult(true);
     }
 
     @Test
     public void testEndVideo_withoutStarting() {
         camera.setMode(Mode.VIDEO);
-        waitForOpen(true);
+        openSync(true);
         camera.stopVideo();
-        waitForVideoEnd(false);
+        waitForVideoResult(false);
     }
 
     @Test
     public void testEndVideo_withMaxSize() {
         camera.setMode(Mode.VIDEO);
         camera.setVideoMaxSize(3000*1000); // Less is risky
-        waitForOpen(true);
+        openSync(true);
-        waitForVideoStart();
+        takeVideoSync(true);
-        waitForVideoEnd(true);
+        waitForVideoResult(true);
     }
 
     @Test
     public void testEndVideo_withMaxDuration() {
         camera.setMode(Mode.VIDEO);
         camera.setVideoMaxDuration(4000);
-        waitForOpen(true);
+        openSync(true);
-        waitForVideoStart();
+        takeVideoSync(true);
-        waitForVideoEnd(true);
+        waitForVideoResult(true);
     }
 
     //endregion
@@ -488,7 +534,7 @@ public abstract class CameraIntegrationTest extends BaseTest {
 
     @Test
     public void testStartAutoFocus() {
-        CameraOptions o = waitForOpen(true);
+        CameraOptions o = openSync(true);
 
         final Op<PointF> focus = new Op<>(true);
         doEndTask(focus, 0).when(listener).onAutoFocusStart(any(PointF.class));
@@ -505,7 +551,7 @@ public abstract class CameraIntegrationTest extends BaseTest {
 
     @Test
     public void testStopAutoFocus() {
-        CameraOptions o = waitForOpen(true);
+        CameraOptions o = openSync(true);
 
         final Op<PointF> focus = new Op<>(true);
         doEndTask(focus, 1).when(listener).onAutoFocusEnd(anyBoolean(), any(PointF.class));
@@ -528,13 +574,13 @@ public abstract class CameraIntegrationTest extends BaseTest {
     @Test
     public void testCapturePicture_beforeStarted() {
         camera.takePicture();
-        waitForPicture(false);
+        waitForPictureResult(false);
     }
 
     @Test
     public void testCapturePicture_concurrentCalls() throws Exception {
         // Second take should fail.
-        waitForOpen(true);
+        openSync(true);
 
         CountDownLatch latch = new CountDownLatch(2);
         doCountDown(latch).when(listener).onPictureTaken(any(PictureResult.class));
@@ -548,12 +594,12 @@ public abstract class CameraIntegrationTest extends BaseTest {
 
     @Test
     public void testCapturePicture_size() throws Exception {
-        waitForOpen(true);
+        openSync(true);
         // PictureSize can still be null after opened.
         while (camera.getPictureSize() == null) {}
         Size size = camera.getPictureSize();
         camera.takePicture();
-        PictureResult result = waitForPicture(true);
+        PictureResult result = waitForPictureResult(true);
         Bitmap bitmap = CameraUtils.decodeBitmap(result.getData(), Integer.MAX_VALUE, Integer.MAX_VALUE);
         assertEquals(result.getSize(), size);
         assertEquals(bitmap.getWidth(), size.getWidth());
@@ -566,7 +612,7 @@ public abstract class CameraIntegrationTest extends BaseTest {
     @Test(expected = RuntimeException.class)
     public void testCapturePicture_whileInVideoMode() throws Throwable {
         camera.setMode(Mode.VIDEO);
-        waitForOpen(true);
+        openSync(true);
         camera.takePicture();
         waitForUiException();
     }
@@ -574,13 +620,13 @@ public abstract class CameraIntegrationTest extends BaseTest {
     @Test
     public void testCaptureSnapshot_beforeStarted() {
         camera.takePictureSnapshot();
-        waitForPicture(false);
+        waitForPictureResult(false);
     }
 
     @Test
     public void testCaptureSnapshot_concurrentCalls() throws Exception {
         // Second take should fail.
-        waitForOpen(true);
+        openSync(true);
 
         CountDownLatch latch = new CountDownLatch(2);
         doCountDown(latch).when(listener).onPictureTaken(any(PictureResult.class));
@@ -594,13 +640,13 @@ public abstract class CameraIntegrationTest extends BaseTest {
 
     @Test
     public void testCaptureSnapshot_size() throws Exception {
-        waitForOpen(true);
+        openSync(true);
         // SnapshotSize can still be null after opened.
         while (camera.getSnapshotSize() == null) {}
         Size size = camera.getSnapshotSize();
         camera.takePictureSnapshot();
 
-        PictureResult result = waitForPicture(true);
+        PictureResult result = waitForPictureResult(true);
         Bitmap bitmap = CameraUtils.decodeBitmap(result.getData(), Integer.MAX_VALUE, Integer.MAX_VALUE);
         assertEquals(result.getSize(), size);
         assertEquals(bitmap.getWidth(), size.getWidth());
@@ -626,7 +672,7 @@ public abstract class CameraIntegrationTest extends BaseTest {
     public void testFrameProcessing_simple() throws Exception {
         FrameProcessor processor = mock(FrameProcessor.class);
         camera.addFrameProcessor(processor);
-        waitForOpen(true);
+        openSync(true);
 
         assert30Frames(processor);
     }
@@ -635,12 +681,12 @@ public abstract class CameraIntegrationTest extends BaseTest {
     public void testFrameProcessing_afterSnapshot() throws Exception {
         FrameProcessor processor = mock(FrameProcessor.class);
         camera.addFrameProcessor(processor);
-        waitForOpen(true);
+        openSync(true);
 
         // In Camera1, snapshots will clear the preview callback
         // Ensure we restore correctly
         camera.takePictureSnapshot();
-        waitForPicture(true);
+        waitForPictureResult(true);
 
         assert30Frames(processor);
     }
@@ -649,9 +695,9 @@ public abstract class CameraIntegrationTest extends BaseTest {
     public void testFrameProcessing_afterRestart() throws Exception {
         FrameProcessor processor = mock(FrameProcessor.class);
         camera.addFrameProcessor(processor);
-        waitForOpen(true);
+        openSync(true);
-        waitForClose(true);
+        closeSync(true);
-        waitForOpen(true);
+        openSync(true);
 
         assert30Frames(processor);
     }
@@ -662,9 +708,9 @@ public abstract class CameraIntegrationTest extends BaseTest {
         FrameProcessor processor = mock(FrameProcessor.class);
         camera.addFrameProcessor(processor);
         camera.setMode(Mode.VIDEO);
-        waitForOpen(true);
+        openSync(true);
-        camera.takeVideo(new File(context().getFilesDir(), "video.mp4"), 4000);
+        takeVideoSync(true,4000);
-        waitForVideoEnd(true);
+        waitForVideoResult(true);
         assert30Frames(processor);
     }
 
@@ -676,7 +722,7 @@ public abstract class CameraIntegrationTest extends BaseTest {
         FrameProcessor source = new FreezeReleaseFrameProcessor();
         FrameProcessor processor = spy(source);
         camera.addFrameProcessor(processor);
-        waitForOpen(true);
+        openSync(true);
 
         assert30Frames(processor);
     }

cameraview/src/androidTest/java/com/otaliastudios/cameraview/engine/MockCameraEngine.java

@@ -177,4 +177,9 @@ public class MockCameraEngine extends CameraEngine {
     protected boolean collectCameraInfo(@NonNull Facing facing) {
         return true;
     }
+
+    @Override
+    public void onVideoRecordingStart() {
+
+    }
 }

cameraview/src/androidTest/java/com/otaliastudios/cameraview/video/VideoRecorderTest.java

@@ -2,9 +2,7 @@ package com.otaliastudios.cameraview.video;
 
 
 import com.otaliastudios.cameraview.BaseTest;
-import com.otaliastudios.cameraview.PictureResult;
 import com.otaliastudios.cameraview.VideoResult;
-import com.otaliastudios.cameraview.video.VideoRecorder;
 
 import androidx.test.ext.junit.runners.AndroidJUnit4;
 import androidx.test.filters.SmallTest;
@@ -29,7 +27,7 @@ public class VideoRecorderTest extends BaseTest {
         VideoRecorder.VideoResultListener listener = Mockito.mock(VideoRecorder.VideoResultListener.class);
         VideoRecorder recorder = new VideoRecorder(listener) {
             @Override
-            protected void onStart() { }
+            protected void onStart() { dispatchVideoRecordingStart(); }
 
             @Override
             protected void onStop() {
@@ -37,6 +35,8 @@ public class VideoRecorderTest extends BaseTest {
             }
         };
         recorder.start(result);
+        Mockito.verify(listener,Mockito.times(1) )
+                .onVideoRecordingStart();
         recorder.stop();
         Mockito.verify(listener, Mockito.times(1))
                 .onVideoResult(result, null);

cameraview/src/main/java/com/otaliastudios/cameraview/CameraListener.java

@@ -127,4 +127,15 @@ public abstract class CameraListener {
     @UiThread
     public void onExposureCorrectionChanged(float newValue, @NonNull float[] bounds, @Nullable PointF[] fingers) { }
 
+
+    /**
+     * Notifies that the actual video recording has started
+     * This is the time when actual frames recording starts.
+     * This can be used to show some indicator while the actual video recording.
+     */
+    @UiThread
+    public void onVideoRecordingStart() {
+
+    }
+
 }

cameraview/src/main/java/com/otaliastudios/cameraview/CameraView.java

@@ -2062,6 +2062,19 @@ public class CameraView extends FrameLayout implements LifecycleObserver {
                 }
             });
         }
+
+        @Override
+        public void dispatchOnVideoRecordingStart() {
+            mLogger.i("dispatchOnVideoRecordingStart", "dispatchOnVideoRecordingStart");
+            mUiHandler.post(new Runnable() {
+                @Override
+                public void run() {
+                    for (CameraListener listener : mListeners) {
+                        listener.onVideoRecordingStart();
+                    }
+                }
+            });
+        }
     }
 
     //endregion

cameraview/src/main/java/com/otaliastudios/cameraview/engine/Camera2Engine.java

@@ -181,6 +181,9 @@ public class Camera2Engine extends CameraEngine implements ImageReader.OnImageAv
             mRepeatingRequestBuilder.addTarget(mFrameProcessingSurface);
         }
         for (Surface extraSurface : extraSurfaces) {
+            if (extraSurface == null) {
+                throw new IllegalArgumentException("Should not add a null surface.");
+            }
             mRepeatingRequestBuilder.addTarget(extraSurface);
         }
     }

cameraview/src/main/java/com/otaliastudios/cameraview/engine/CameraEngine.java

@@ -134,6 +134,7 @@ public abstract class CameraEngine implements
         void dispatchOnExposureCorrectionChanged(float newValue, @NonNull float[] bounds, @Nullable PointF[] fingers);
         void dispatchFrame(Frame frame);
         void dispatchError(CameraException exception);
+        void dispatchOnVideoRecordingStart();
     }
 
     private static final String TAG = CameraEngine.class.getSimpleName();
@@ -198,7 +199,6 @@ public abstract class CameraEngine implements
     private Step mAllStep = new Step("all", mStepCallback);
 
     // Ops used for testing.
-    @VisibleForTesting Op<Void> mStartVideoOp = new Op<>();
     @VisibleForTesting(otherwise = VisibleForTesting.PROTECTED) Op<Void> mZoomOp = new Op<>();
     @VisibleForTesting(otherwise = VisibleForTesting.PROTECTED) Op<Void> mExposureCorrectionOp = new Op<>();
     @VisibleForTesting(otherwise = VisibleForTesting.PROTECTED) Op<Void> mFlashOp = new Op<>();
@@ -1120,8 +1120,8 @@ public abstract class CameraEngine implements
             @Override
             public void run() {
                 LOG.v("takeVideo", "performing. BindState:", getBindState(), "isTakingVideo:", isTakingVideo());
-                if (getBindState() < STATE_STARTED) { mStartVideoOp.end(null); return; }
+                if (getBindState() < STATE_STARTED) return;
-                if (isTakingVideo()) { mStartVideoOp.end(null); return; }
+                if (isTakingVideo()) return;
                 if (mMode == Mode.PICTURE) {
                     throw new IllegalStateException("Can't record video while in PICTURE mode");
                 }
@@ -1136,7 +1136,6 @@ public abstract class CameraEngine implements
                 stub.videoBitRate = mVideoBitRate;
                 stub.audioBitRate = mAudioBitRate;
                 onTakeVideo(stub);
-                mStartVideoOp.end(null);
             }
         });
     }
@@ -1152,8 +1151,8 @@ public abstract class CameraEngine implements
             @Override
             public void run() {
                 LOG.v("takeVideoSnapshot", "performing. BindState:", getBindState(), "isTakingVideo:", isTakingVideo());
-                if (getBindState() < STATE_STARTED) { mStartVideoOp.end(null); return; }
+                if (getBindState() < STATE_STARTED) return;
-                if (isTakingVideo()) { mStartVideoOp.end(null); return; }
+                if (isTakingVideo()) return;
                 stub.file = file;
                 stub.isSnapshot = true;
                 stub.videoCodec = mVideoCodec;
@@ -1165,7 +1164,6 @@ public abstract class CameraEngine implements
                 stub.maxSize = mVideoMaxSize;
                 stub.maxDuration = mVideoMaxDuration;
                 onTakeVideoSnapshot(stub, viewAspectRatio);
-                mStartVideoOp.end(null);
             }
         });
     }
@@ -1196,6 +1194,12 @@ public abstract class CameraEngine implements
         }
     }
 
+    @Override
+    public void onVideoRecordingStart() {
+        mCallback.dispatchOnVideoRecordingStart();
+    }
+
+
     @WorkerThread
     protected abstract void onTakePicture(@NonNull PictureResult.Stub stub);
 

cameraview/src/main/java/com/otaliastudios/cameraview/video/FullVideoRecorder.java

@@ -130,6 +130,7 @@ public abstract class FullVideoRecorder extends VideoRecorder {
 
         try {
             mMediaRecorder.start();
+            dispatchVideoRecordingStart();
         } catch (Exception e) {
             LOG.w("start:", "Error while starting media recorder.", e);
             mResult = null;

cameraview/src/main/java/com/otaliastudios/cameraview/video/SnapshotVideoRecorder.java

@@ -60,6 +60,7 @@ public class SnapshotVideoRecorder extends VideoRecorder implements RendererFram
         mPreview.addRendererFrameCallback(this);
         mFlipped = mEngine.getAngles().flip(Reference.SENSOR, Reference.VIEW);
         mDesiredState = STATE_RECORDING;
+        dispatchVideoRecordingStart();
     }
 
     @Override

cameraview/src/main/java/com/otaliastudios/cameraview/video/VideoRecorder.java

@@ -24,6 +24,11 @@ public abstract class VideoRecorder {
          * @param exception the error or null if everything went fine
          */
         void onVideoResult(@Nullable VideoResult.Stub result, @Nullable Exception exception);
+
+        /**
+         * The callback for the actual video recording starting.
+         */
+        void onVideoRecordingStart();
     }
 
     @VisibleForTesting(otherwise = VisibleForTesting.PROTECTED) VideoResult.Stub mResult;
@@ -84,4 +89,16 @@ public abstract class VideoRecorder {
         mResult = null;
         mError = null;
     }
+
+    /**
+     * Subclasses can call this to notify that the video recording has started,
+     * this will be called when camera is prepared and started.
+     */
+    @SuppressWarnings("WeakerAccess")
+    @CallSuper
+    protected void dispatchVideoRecordingStart(){
+        if(mListener != null){
+            mListener.onVideoRecordingStart();
+        }
+    }
 }

docs/_posts/2018-12-20-camera-events.md

@@ -37,6 +37,8 @@ camera.addCameraListener(new CameraListener() {
     public void onZoomChanged(float newValue, float[] bounds, PointF[] fingers) {}
     
     public void onExposureCorrectionChanged(float newValue, float[] bounds, PointF[] fingers) {}
+
+    public void onVideoRecordingStart() {}
 });
 ```
 

docs/_posts/2018-12-20-changelog.md

@@ -8,9 +8,11 @@ order: 3
 
 New versions are released through GitHub, so the reference page is the [GitHub Releases](https://github.com/natario1/CameraView/releases) page.
 
-### v2.0.0-*** (to be released)
+### v2.0.0 (to be released)
 
-- New: `cameraUseDeviceOrientation` XML attribute and `setUseDeviceOrientation()` method to disable considering the device orientation for outputs. ([#497][497])
+- New: added `onVideoRecordingStart()` to be notified when video recording starts, thanks to [@agrawalsuneet][agrawalsuneet] ([#498][498])
+- New: added `cameraUseDeviceOrientation` to choose whether picture and video outputs should consider the device orientation or not ([#497][497])
+- Improvement: improved Camera2 stability and various bugs fixed (e.g. [#501][501])
 
 ### v2.0.0-beta06
 
@@ -55,6 +57,7 @@ If you were using `focusWithMarker`, you can [add back the old marker](../docs/m
 This is the first beta release. For changes with respect to v1, please take a look at the [migration guide](../extra/v1-migration-guide.html).
 
 [cneuwirt]: https://github.com/cneuwirt
+[agrawalsuneet]: https://github.com/agrawalsuneet
 
 [356]: https://github.com/natario1/CameraView/pull/356
 [360]: https://github.com/natario1/CameraView/pull/360
@@ -69,4 +72,6 @@ This is the first beta release. For changes with respect to v1, please take a lo
 [482]: https://github.com/natario1/CameraView/pull/482
 [484]: https://github.com/natario1/CameraView/pull/484
 [490]: https://github.com/natario1/CameraView/pull/490
-[497]: https://github.com/natario1/CameraView/pull/497
+[497]: https://github.com/natario1/CameraView/pull/497
+[498]: https://github.com/natario1/CameraView/pull/498
+[501]: https://github.com/natario1/CameraView/pull/501