Camera2 support for frame processing

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

@@ -12,6 +12,7 @@ import com.otaliastudios.cameraview.VideoResult;
 import com.otaliastudios.cameraview.controls.Audio;
 import com.otaliastudios.cameraview.controls.Facing;
 import com.otaliastudios.cameraview.controls.Flash;
+import com.otaliastudios.cameraview.frame.FrameManager;
 import com.otaliastudios.cameraview.gesture.Gesture;
 import com.otaliastudios.cameraview.controls.Hdr;
 import com.otaliastudios.cameraview.controls.Mode;
@@ -176,8 +177,10 @@ public class MockCameraEngine extends CameraEngine {
         mFocusStarted = true;
     }
 
+    @NonNull
     @Override
-    public void onBufferAvailable(@NonNull byte[] buffer) {
+    protected FrameManager instantiateFrameManager() {
+        return new FrameManager(2, null);
     }
 
     @Override

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

@@ -1911,7 +1911,13 @@ public class CameraView extends FrameLayout implements LifecycleObserver {
                     @Override
                     public void run() {
                         for (FrameProcessor processor : mFrameProcessors) {
+                            try {
                                 processor.process(frame);
+                            } catch (Exception e) {
+                                mLogger.w("dispatchFrame:", "Error during processor implementation.",
+                                        "Can happen when camera is closed while processors are running.",
+                                        e);
+                            }
                         }
                         frame.release();
                     }

cameraview/src/main/java/com/otaliastudios/cameraview/engine/Camera1Engine.java

@@ -26,6 +26,7 @@ import com.otaliastudios.cameraview.PictureResult;
 import com.otaliastudios.cameraview.VideoResult;
 import com.otaliastudios.cameraview.controls.Facing;
 import com.otaliastudios.cameraview.controls.Flash;
+import com.otaliastudios.cameraview.frame.FrameManager;
 import com.otaliastudios.cameraview.gesture.Gesture;
 import com.otaliastudios.cameraview.controls.Hdr;
 import com.otaliastudios.cameraview.controls.Mode;
@@ -47,7 +48,10 @@ import java.util.List;
 
 
 @SuppressWarnings("deprecation")
-public class Camera1Engine extends CameraEngine implements Camera.PreviewCallback, Camera.ErrorCallback {
+public class Camera1Engine extends CameraEngine implements
+        Camera.PreviewCallback,
+        Camera.ErrorCallback,
+        FrameManager.BufferCallback {
 
     private static final String TAG = Camera1Engine.class.getSimpleName();
     private static final CameraLogger LOG = CameraLogger.create(TAG);
@@ -284,6 +288,12 @@ public class Camera1Engine extends CameraEngine implements Camera.PreviewCallbac
         mHasFrameProcessors = hasFrameProcessors;
     }
 
+    @NonNull
+    @Override
+    protected FrameManager instantiateFrameManager() {
+        return new FrameManager(2, this);
+    }
+
     @Override
     public void onBufferAvailable(@NonNull byte[] buffer) {
         // TODO: sync with handler?

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

@@ -3,6 +3,8 @@ package com.otaliastudios.cameraview.engine;
 import android.annotation.SuppressLint;
 import android.content.Context;
 import android.graphics.Camera;
+import android.graphics.ImageFormat;
+import android.graphics.PixelFormat;
 import android.graphics.PointF;
 import android.graphics.Rect;
 import android.graphics.SurfaceTexture;
@@ -14,6 +16,8 @@ import android.hardware.camera2.CameraManager;
 import android.hardware.camera2.CaptureRequest;
 import android.hardware.camera2.params.StreamConfigurationMap;
 import android.location.Location;
+import android.media.Image;
+import android.media.ImageReader;
 import android.media.MediaCodec;
 import android.os.Build;
 import android.view.Surface;
@@ -33,14 +37,20 @@ import com.otaliastudios.cameraview.controls.Flash;
 import com.otaliastudios.cameraview.controls.Hdr;
 import com.otaliastudios.cameraview.controls.Mode;
 import com.otaliastudios.cameraview.controls.WhiteBalance;
+import com.otaliastudios.cameraview.frame.Frame;
+import com.otaliastudios.cameraview.frame.FrameManager;
 import com.otaliastudios.cameraview.gesture.Gesture;
 import com.otaliastudios.cameraview.internal.utils.CropHelper;
+import com.otaliastudios.cameraview.internal.utils.ImageHelper;
+import com.otaliastudios.cameraview.internal.utils.WorkerHandler;
 import com.otaliastudios.cameraview.picture.SnapshotGlPictureRecorder;
 import com.otaliastudios.cameraview.preview.GlCameraPreview;
 import com.otaliastudios.cameraview.size.AspectRatio;
 import com.otaliastudios.cameraview.size.Size;
+import com.otaliastudios.cameraview.size.SizeSelectors;
 import com.otaliastudios.cameraview.video.Full2VideoRecorder;
 import com.otaliastudios.cameraview.video.SnapshotVideoRecorder;
+import com.otaliastudios.cameraview.video.VideoRecorder;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -57,13 +67,15 @@ import androidx.annotation.WorkerThread;
 // TODO exposure correction
 // TODO autofocus
 // TODO pictures
-// TODO frame processor
 @RequiresApi(Build.VERSION_CODES.LOLLIPOP)
-public class Camera2Engine extends CameraEngine {
+public class Camera2Engine extends CameraEngine implements ImageReader.OnImageAvailableListener {
 
     private static final String TAG = Camera2Engine.class.getSimpleName();
     private static final CameraLogger LOG = CameraLogger.create(TAG);
 
+    private static final int FRAME_PROCESSING_FORMAT = ImageFormat.NV21;
+    private static final int FRAME_PROCESSING_INPUT_FORMAT = ImageFormat.YUV_420_888;
+
     private final CameraManager mManager;
     private String mCameraId;
     private CameraDevice mCamera;
@@ -72,6 +84,11 @@ public class Camera2Engine extends CameraEngine {
     private CaptureRequest.Builder mRepeatingRequestBuilder;
     private CaptureRequest mRepeatingRequest;
 
+    // Frame processing
+    private Size mFrameProcessingSize;
+    private ImageReader mFrameProcessingReader; // need this or the reader surface is collected
+    private final WorkerHandler mFrameConversionHandler;
+
     private Surface mPreviewStreamSurface;
     private Surface mFrameProcessingSurface;
 
@@ -85,6 +102,7 @@ public class Camera2Engine extends CameraEngine {
         super(callback);
         mMapper = Mapper.get(Engine.CAMERA2);
         mManager = (CameraManager) mCallback.getContext().getSystemService(Context.CAMERA_SERVICE);
+        mFrameConversionHandler = WorkerHandler.get("CameraViewFrameConversion");
     }
 
     //region Utilities
@@ -374,9 +392,29 @@ public class Camera2Engine extends CameraEngine {
 
         // 4. FRAME PROCESSING
         if (mHasFrameProcessors) {
-            // TODO
+            // Choose the size.
+            StreamConfigurationMap streamMap = mCameraCharacteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
+            if (streamMap == null) throw new RuntimeException("StreamConfigurationMap is null. Should not happen.");
+            android.util.Size[] aSizes = streamMap.getOutputSizes(FRAME_PROCESSING_INPUT_FORMAT);
+            List<Size> sizes = new ArrayList<>();
+            for (android.util.Size aSize : aSizes) {
+                sizes.add(new Size(aSize.getWidth(), aSize.getHeight()));
+            }
+            mFrameProcessingSize = SizeSelectors.and(
+                    SizeSelectors.maxWidth(Math.min(700, mPreviewStreamSize.getWidth())),
+                    SizeSelectors.maxHeight(Math.min(700, mPreviewStreamSize.getHeight())),
+                    SizeSelectors.biggest()).select(sizes).get(0);
+            mFrameProcessingReader = ImageReader.newInstance(
+                    mFrameProcessingSize.getWidth(),
+                    mFrameProcessingSize.getHeight(),
+                    FRAME_PROCESSING_INPUT_FORMAT,
+                    2);
+            mFrameProcessingReader.setOnImageAvailableListener(this, mFrameConversionHandler.getHandler());
+            mFrameProcessingSurface = mFrameProcessingReader.getSurface();
             outputSurfaces.add(mFrameProcessingSurface);
         } else {
+            mFrameProcessingReader = null;
+            mFrameProcessingSize = null;
             mFrameProcessingSurface = null;
         }
 
@@ -414,23 +452,28 @@ public class Camera2Engine extends CameraEngine {
             throw new IllegalStateException("previewStreamSize should not be null at this point.");
         }
         mPreview.setStreamSize(previewSizeForView.getWidth(), previewSizeForView.getHeight());
-
-        // Set the preview rotation.
         mPreview.setDrawRotation(mDisplayOffset);
+        if (mHasFrameProcessors) {
+            getFrameManager().setUp(ImageFormat.getBitsPerPixel(FRAME_PROCESSING_FORMAT), mFrameProcessingSize);
+        }
 
-        // TODO mCamera.setPreviewCallbackWithBuffer(null); // Release anything left
+        LOG.i("onStartPreview", "Starting preview.");
-        // TODO mCamera.setPreviewCallbackWithBuffer(this); // Add ourselves
-        // TODO mFrameManager.setUp(ImageFormat.getBitsPerPixel(mPreviewStreamFormat), mPreviewStreamSize);
-
-        LOG.i("onStartPreview", "Starting preview with startPreview().");
         addRepeatingRequestBuilderSurfaces();
         applyRepeatingRequestBuilder(false, CameraException.REASON_FAILED_TO_START_PREVIEW, null);
         LOG.i("onStartPreview", "Started preview.");
 
         // Start delayed video if needed.
         if (mFullVideoPendingStub != null) {
-            // Do not call takeVideo. It will reset some stub parameters that the recorder sets.
+            // Do not call takeVideo/onTakeVideo. It will reset some stub parameters that the recorder sets.
-            onTakeVideo(mFullVideoPendingStub);
+            // Also we are posting this so that doTakeVideo sees a started preview.
+            final VideoResult.Stub stub = mFullVideoPendingStub;
+            mFullVideoPendingStub = null;
+            mHandler.post(new Runnable() {
+                @Override
+                public void run() {
+                    doTakeVideo(stub);
+                }
+            });
         }
         return Tasks.forResult(null);
     }
@@ -449,8 +492,9 @@ public class Camera2Engine extends CameraEngine {
             mVideoRecorder = null;
         }
         mPictureRecorder = null;
+        if (mHasFrameProcessors) {
             getFrameManager().release();
-        // TODO mCamera.setPreviewCallbackWithBuffer(null); // Release anything left
+        }
         try {
             // NOTE: should we wait for onReady() like docs say?
             // Leaving this synchronous for now.
@@ -478,6 +522,11 @@ public class Camera2Engine extends CameraEngine {
         mPreviewStreamSurface = null;
         mPreviewStreamSize = null;
         mCaptureSize = null;
+        mFrameProcessingSize = null;
+        if (mFrameProcessingReader != null) {
+            mFrameProcessingReader.close();
+            mFrameProcessingReader = null;
+        }
         mSession.close();
         mSession = null;
         return Tasks.forResult(null);
@@ -537,15 +586,9 @@ public class Camera2Engine extends CameraEngine {
         stub.size = flip(REF_SENSOR, REF_OUTPUT) ? mCaptureSize.flip() : mCaptureSize;
         if (!Full2VideoRecorder.SUPPORTS_PERSISTENT_SURFACE) {
             // On API 21 and 22, we must restart the session at each time.
-            if (stub == mFullVideoPendingStub) {
-                // We have restarted and are ready to take the video.
-                doTakeVideo(mFullVideoPendingStub);
-                mFullVideoPendingStub = null;
-            } else {
             // Save the pending data and restart the session.
             mFullVideoPendingStub = stub;
             restartBind();
-            }
         } else {
             doTakeVideo(stub);
         }
@@ -820,9 +863,48 @@ public class Camera2Engine extends CameraEngine {
 
     //region FrameProcessing
 
+    @NonNull
     @Override
-    public void onBufferAvailable(@NonNull byte[] buffer) {
+    protected FrameManager instantiateFrameManager() {
-        // TODO
+        return new FrameManager(2, null);
+    }
+
+    @Override
+    public void onImageAvailable(ImageReader reader) {
+        byte[] data = getFrameManager().getBuffer();
+        if (data == null) {
+            LOG.w("onImageAvailable", "no byte buffer!");
+            return;
+        }
+        Image image = null;
+        try {
+            image = reader.acquireLatestImage();
+        } catch (IllegalStateException ignore) { }
+        if (image == null) {
+            LOG.w("onImageAvailable", "we have a byte buffer but no Image!");
+            getFrameManager().onBufferUnused(data);
+            return;
+        }
+        LOG.i("onImageAvailable", "we have both a byte buffer and an Image.");
+        try {
+            ImageHelper.convertToNV21(image, data);
+        } catch (Exception e) {
+            LOG.w("onImageAvailable", "error while converting.");
+            getFrameManager().onBufferUnused(data);
+            image.close();
+            return;
+        }
+        image.close();
+        if (getEngineState() == STATE_STARTED) {
+            Frame frame = getFrameManager().getFrame(data,
+                    System.currentTimeMillis(),
+                    offset(REF_SENSOR, REF_OUTPUT),
+                    mFrameProcessingSize,
+                    FRAME_PROCESSING_FORMAT);
+            mCallback.dispatchFrame(frame);
+        } else {
+            getFrameManager().onBufferUnused(data);
+        }
     }
 
     @Override

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

@@ -115,7 +115,6 @@ import java.util.concurrent.Executor;
  */
 public abstract class CameraEngine implements
         CameraPreview.SurfaceCallback,
-        FrameManager.BufferCallback,
         PictureRecorder.PictureResultListener,
         VideoRecorder.VideoResultListener {
 
@@ -224,7 +223,7 @@ public abstract class CameraEngine implements
         mCrashHandler = new Handler(Looper.getMainLooper());
         mHandler = WorkerHandler.get("CameraViewEngine");
         mHandler.getThread().setUncaughtExceptionHandler(new CrashExceptionHandler());
-        mFrameManager = new FrameManager(2, this);
+        mFrameManager = instantiateFrameManager();
     }
 
     public void setPreview(@NonNull CameraPreview cameraPreview) {
@@ -474,11 +473,11 @@ public abstract class CameraEngine implements
 
     @SuppressWarnings("WeakerAccess")
     protected void restartBind() {
-        LOG.i("restartPreviewAndBind", "posting.");
+        LOG.i("restartBind", "posting.");
         mHandler.run(new Runnable() {
             @Override
             public void run() {
-                LOG.i("restartPreviewAndBind", "executing.");
+                LOG.i("restartBind", "executing.");
                 stopPreview(false).continueWithTask(mHandler.getExecutor(), new Continuation<Void, Task<Void>>() {
                     @Override
                     public Task<Void> then(@NonNull Task<Void> task) {
@@ -605,11 +604,14 @@ public abstract class CameraEngine implements
 
                 // Compute a new camera preview size and apply.
                 Size newSize = computePreviewStreamSize();
-                if (newSize.equals(mPreviewStreamSize)) return;
+                if (newSize.equals(mPreviewStreamSize)) {
-                LOG.i("onSurfaceChanged:", "Computed a new preview size. Going on.");
+                    LOG.i("onSurfaceChanged:", "The computed preview size is identical. No op.");
+                } else {
+                    LOG.i("onSurfaceChanged:", "Computed a new preview size. Calling onPreviewStreamSizeChanged().");
                     mPreviewStreamSize = newSize;
                     onPreviewStreamSizeChanged();
                 }
+            }
         });
     }
 
@@ -895,6 +897,14 @@ public abstract class CameraEngine implements
      */
     protected abstract boolean collectCameraInfo(@NonNull Facing facing);
 
+    /**
+     * Called at construction time to get a frame manager that can later be
+     * accessed through {@link #getFrameManager()}.
+     * @return a frame manager
+     */
+    @NonNull
+    protected abstract FrameManager instantiateFrameManager();
+
     // If closed, no-op. If opened, check supported and apply.
     public abstract void setZoom(float zoom, @Nullable PointF[] points, boolean notify);
 
@@ -1353,7 +1363,7 @@ public abstract class CameraEngine implements
         if (targetMinSize == null) throw new IllegalStateException("targetMinSize should not be null here.");
         AspectRatio targetRatio = AspectRatio.of(mCaptureSize.getWidth(), mCaptureSize.getHeight());
         if (flip) targetRatio = targetRatio.flip();
-        LOG.i("size:", "computePreviewStreamSize:", "targetRatio:", targetRatio, "targetMinSize:", targetMinSize);
+        LOG.i("computePreviewStreamSize:", "targetRatio:", targetRatio, "targetMinSize:", targetMinSize);
         SizeSelector matchRatio = SizeSelectors.and( // Match this aspect ratio and sort by biggest
                 SizeSelectors.aspectRatio(targetRatio, 0),
                 SizeSelectors.biggest());

cameraview/src/main/java/com/otaliastudios/cameraview/frame/Frame.java

@@ -1,5 +1,6 @@
 package com.otaliastudios.cameraview.frame;
 
+import com.otaliastudios.cameraview.CameraLogger;
 import com.otaliastudios.cameraview.size.Size;
 
 import androidx.annotation.NonNull;
@@ -10,10 +11,14 @@ import androidx.annotation.VisibleForTesting;
  */
 public class Frame {
 
+    private final static String TAG = Frame.class.getSimpleName();
+    private final static CameraLogger LOG = CameraLogger.create(TAG);
+
     @VisibleForTesting FrameManager mManager;
 
     private byte[] mData = null;
     private long mTime = -1;
+    private long mLastTime = -1;
     private int mRotation = 0;
     private Size mSize = null;
     private int mFormat = -1;
@@ -29,6 +34,7 @@ public class Frame {
 
     private void ensureAlive() {
         if (!isAlive()) {
+            LOG.e("Frame is dead! time:", mTime, "lastTime:", mLastTime);
             throw new RuntimeException("You should not access a released frame. " +
                     "If this frame was passed to a FrameProcessor, you can only use its contents synchronously," +
                     "for the duration of the process() method.");
@@ -38,6 +44,7 @@ public class Frame {
     void set(@NonNull byte[] data, long time, int rotation, @NonNull Size size, int format) {
         this.mData = data;
         this.mTime = time;
+        this.mLastTime = time;
         this.mRotation = rotation;
         this.mSize = size;
         this.mFormat = format;
@@ -73,6 +80,7 @@ public class Frame {
      */
     public void release() {
         if (!isAlive()) return;
+        LOG.v("Frame with time", mTime, "is being released. Has manager:", mManager != null);
 
         if (mManager != null) {
             // If needed, the manager will call releaseManager on us.

cameraview/src/main/java/com/otaliastudios/cameraview/frame/FrameManager.java

@@ -1,6 +1,7 @@
 package com.otaliastudios.cameraview.frame;
 
 
+import com.otaliastudios.cameraview.CameraLogger;
 import com.otaliastudios.cameraview.size.Size;
 
 import androidx.annotation.NonNull;
@@ -25,6 +26,9 @@ import java.util.concurrent.LinkedBlockingQueue;
  */
 public class FrameManager {
 
+    private static final String TAG = FrameManager.class.getSimpleName();
+    private static final CameraLogger LOG = CameraLogger.create(TAG);
+
     /**
      * Receives callbacks on buffer availability
      * (when a Frame is released, we reuse its buffer).
@@ -33,10 +37,24 @@ public class FrameManager {
         void onBufferAvailable(@NonNull byte[] buffer);
     }
 
-    private int mPoolSize;
+    private final int mPoolSize;
-    private int mBufferSize;
+    private int mBufferSize = -1;
-    private BufferCallback mCallback;
+    private LinkedBlockingQueue<Frame> mFrameQueue;
-    private LinkedBlockingQueue<Frame> mQueue;
+    private LinkedBlockingQueue<byte[]> mBufferQueue;
+    private BufferCallback mBufferCallback;
+    private final int mBufferMode;
+
+    /**
+     * In this mode, we have a {@link #mBufferCallback} and dispatch
+     * new buffers to the callback.
+     */
+    private final static int BUFFER_MODE_DISPATCH = 0;
+
+    /**
+     * In this mode, we have a {@link #mBufferQueue} where we store
+     * buffers and only dispatch when requested.
+     */
+    private final static int BUFFER_MODE_ENQUEUE = 1;
 
     /**
      * Construct a new frame manager.
@@ -48,9 +66,14 @@ public class FrameManager {
      */
     public FrameManager(int poolSize, @Nullable BufferCallback callback) {
         mPoolSize = poolSize;
-        mCallback = callback;
+        mFrameQueue = new LinkedBlockingQueue<>(mPoolSize);
-        mQueue = new LinkedBlockingQueue<>(mPoolSize);
+        if (callback != null) {
-        mBufferSize = -1;
+            mBufferCallback = callback;
+            mBufferMode = BUFFER_MODE_DISPATCH;
+        } else {
+            mBufferQueue = new LinkedBlockingQueue<>(mPoolSize);
+            mBufferMode = BUFFER_MODE_ENQUEUE;
+        }
     }
 
     /**
@@ -65,41 +88,46 @@ public class FrameManager {
      */
     public int setUp(int bitsPerPixel, @NonNull Size previewSize) {
         // TODO throw if called twice without release?
-        mBufferSize = getBufferSize(bitsPerPixel, previewSize);
+        long sizeInBits = previewSize.getHeight() * previewSize.getWidth() * bitsPerPixel;
+        mBufferSize = (int) Math.ceil(sizeInBits / 8.0d);
         for (int i = 0; i < mPoolSize; i++) {
-            mCallback.onBufferAvailable(new byte[mBufferSize]);
+            if (mBufferMode == BUFFER_MODE_DISPATCH) {
+                mBufferCallback.onBufferAvailable(new byte[mBufferSize]);
+            } else {
+                mBufferQueue.offer(new byte[mBufferSize]);
+            }
         }
         return mBufferSize;
     }
 
     /**
-     * Releases all frames controlled by this manager and
+     * Returns a new byte buffer than can be filled.
-     * clears the pool.
+     * This can only be called in {@link #BUFFER_MODE_ENQUEUE} mode! Where the frame
+     * manager also holds a queue of the byte buffers.
+     *
+     * If not null, the buffer returned by this method can be filled and used to get
+     * a new frame through {@link #getFrame(byte[], long, int, Size, int)}.
+     *
+     * @return a buffer, or null
      */
-    public void release() {
+    @Nullable
-        for (Frame frame : mQueue) {
+    public byte[] getBuffer() {
-            frame.releaseManager();
+        if (mBufferMode != BUFFER_MODE_ENQUEUE) {
-            frame.release();
+            throw new IllegalStateException("Can't call getBuffer() when not in BUFFER_MODE_ENQUEUE.");
         }
-        mQueue.clear();
+        return mBufferQueue.poll();
-        mBufferSize = -1;
     }
 
-    void onFrameReleased(Frame frame) {
+    /**
-        byte[] buffer = frame.getData();
+     * Can be called if the buffer obtained by {@link #getBuffer()}
-        boolean willRecycle = mQueue.offer(frame);
+     * was not used to construct a frame, so it can be put back into the queue.
-        if (!willRecycle) {
+     * @param buffer a buffer
-            // If frame queue is full, let's drop everything.
+     */
-            frame.releaseManager();
+    public void onBufferUnused(@NonNull byte[] buffer) {
-        } else {
+        if (mBufferMode != BUFFER_MODE_ENQUEUE) {
-            // If frame will be recycled, let's recycle the buffer as well.
+            throw new IllegalStateException("Can't call onBufferUnused() when not in BUFFER_MODE_ENQUEUE.");
-            int currSize = buffer.length;
-            int reqSize = mBufferSize;
-            if (currSize == reqSize && mCallback != null) {
-                mCallback.onBufferAvailable(buffer);
-            }
         }
-
+        mBufferQueue.offer(buffer);
     }
 
     /**
@@ -113,15 +141,58 @@ public class FrameManager {
      *
      * @return a new frame
      */
+    @NonNull
     public Frame getFrame(@NonNull byte[] data, long time, int rotation, @NonNull Size previewSize, int previewFormat) {
-        Frame frame = mQueue.poll();
+        Frame frame = mFrameQueue.poll();
-        if (frame == null) frame = new Frame(this);
+        if (frame != null) {
+            LOG.v("getFrame for time:", time, "RECYCLING.", "Data:", data != null);
+        } else {
+            LOG.v("getFrame for time:", time, "CREATING.", "Data:", data != null);
+            frame = new Frame(this);
+        }
         frame.set(data, time, rotation, previewSize, previewFormat);
         return frame;
     }
 
-    private int getBufferSize(int bitsPerPixel, @NonNull Size previewSize) {
+    /**
-        long sizeInBits = previewSize.getHeight() * previewSize.getWidth() * bitsPerPixel;
+     * Releases all frames controlled by this manager and
-        return (int) Math.ceil(sizeInBits / 8.0d);
+     * clears the pool.
+     * In BUFFER_MODE_ENQUEUE, releases also all the buffers.
+     */
+    public void release() {
+        LOG.w("Releasing all frames!");
+        for (Frame frame : mFrameQueue) {
+            frame.releaseManager();
+            frame.release();
+        }
+        mFrameQueue.clear();
+        if (mBufferMode == BUFFER_MODE_ENQUEUE) {
+            mBufferQueue.clear();
+        }
+        mBufferSize = -1;
+    }
+
+    /**
+     * Called by child frames when they are released.
+     * @param frame the released frame
+     */
+    void onFrameReleased(@NonNull Frame frame) {
+        byte[] buffer = frame.getData();
+        boolean willRecycle = mFrameQueue.offer(frame);
+        if (!willRecycle) {
+            // If frame queue is full, let's drop everything.
+            frame.releaseManager();
+        } else {
+            // If frame will be recycled, let's recycle the buffer as well.
+            int currSize = buffer.length;
+            int reqSize = mBufferSize;
+            if (currSize == reqSize) {
+                if (mBufferMode == BUFFER_MODE_DISPATCH) {
+                    mBufferCallback.onBufferAvailable(buffer);
+                } else {
+                    mBufferQueue.offer(buffer);
+                }
+            }
+        }
     }
 }

cameraview/src/main/java/com/otaliastudios/cameraview/internal/utils/ImageHelper.java

@@ -0,0 +1,96 @@
+package com.otaliastudios.cameraview.internal.utils;
+
+import android.graphics.ImageFormat;
+import android.graphics.Rect;
+import android.media.Image;
+
+import com.otaliastudios.cameraview.size.AspectRatio;
+import com.otaliastudios.cameraview.size.Size;
+
+import java.nio.ByteBuffer;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.RequiresApi;
+
+/**
+ * Conversions for {@link android.media.Image}s into byte arrays.
+ */
+@RequiresApi(19)
+public class ImageHelper {
+
+    // https://stackoverflow.com/a/52740776/4288782
+    public static void convertToNV21(@NonNull Image image, @NonNull byte[] result) {
+        if (image.getFormat() != ImageFormat.YUV_420_888) {
+            throw new IllegalStateException("CAn only convert from YUV_420_888.");
+        }
+        int width = image.getWidth();
+        int height = image.getHeight();
+        int ySize = width * height;
+        int uvSize = width * height / 4;
+
+        ByteBuffer yBuffer = image.getPlanes()[0].getBuffer(); // Y
+        ByteBuffer uBuffer = image.getPlanes()[1].getBuffer(); // U
+        ByteBuffer vBuffer = image.getPlanes()[2].getBuffer(); // V
+
+        int rowStride = image.getPlanes()[0].getRowStride();
+
+        if (image.getPlanes()[0].getPixelStride() != 1) {
+            throw new AssertionError("Something wrong in convertToNV21");
+        }
+
+        int pos = 0;
+
+        if (rowStride == width) { // likely
+            yBuffer.get(result, 0, ySize);
+            pos += ySize;
+        }
+        else {
+            int yBufferPos = width - rowStride; // not an actual position
+            for (; pos<ySize; pos+=width) {
+                yBufferPos += rowStride - width;
+                yBuffer.position(yBufferPos);
+                yBuffer.get(result, pos, width);
+            }
+        }
+
+        rowStride = image.getPlanes()[2].getRowStride();
+        int pixelStride = image.getPlanes()[2].getPixelStride();
+
+        if (rowStride != image.getPlanes()[1].getRowStride()) {
+            throw new AssertionError("Something wrong in convertToNV21");
+        }
+        if (pixelStride != image.getPlanes()[1].getPixelStride()) {
+            throw new AssertionError("Something wrong in convertToNV21");
+        }
+
+        if (pixelStride == 2 && rowStride == width && uBuffer.get(0) == vBuffer.get(1)) {
+            // maybe V an U planes overlap as per NV21, which means vBuffer[1] is alias of uBuffer[0]
+            byte savePixel = vBuffer.get(1);
+            vBuffer.put(1, (byte)0);
+            if (uBuffer.get(0) == 0) {
+                vBuffer.put(1, (byte)255);
+                //noinspection ConstantConditions
+                if (uBuffer.get(0) == 255) {
+                    vBuffer.put(1, savePixel);
+                    vBuffer.get(result, ySize, uvSize);
+                    return; // shortcut
+                }
+            }
+
+            // unfortunately, the check failed. We must save U and V pixel by pixel
+            vBuffer.put(1, savePixel);
+        }
+
+        // other optimizations could check if (pixelStride == 1) or (pixelStride == 2),
+        // but performance gain would be less significant
+
+        for (int row=0; row<height/2; row++) {
+            for (int col=0; col<width/2; col++) {
+                int vuPos = col*pixelStride + row*rowStride;
+                result[pos++] = vBuffer.get(vuPos);
+                result[pos++] = uBuffer.get(vuPos);
+            }
+        }
+    }
+}
+

demo/src/main/java/com/otaliastudios/cameraview/demo/CameraActivity.java

@@ -7,6 +7,7 @@ import androidx.annotation.NonNull;
 import com.google.android.material.bottomsheet.BottomSheetBehavior;
 import androidx.appcompat.app.AppCompatActivity;
 
+import android.util.Log;
 import android.view.View;
 import android.view.ViewGroup;
 import android.view.ViewTreeObserver;
@@ -20,6 +21,8 @@ import com.otaliastudios.cameraview.CameraView;
 import com.otaliastudios.cameraview.PictureResult;
 import com.otaliastudios.cameraview.controls.Mode;
 import com.otaliastudios.cameraview.VideoResult;
+import com.otaliastudios.cameraview.frame.Frame;
+import com.otaliastudios.cameraview.frame.FrameProcessor;
 import com.otaliastudios.cameraview.size.SizeSelectors;
 
 import java.io.File;
@@ -42,6 +45,16 @@ public class CameraActivity extends AppCompatActivity implements View.OnClickLis
         camera = findViewById(R.id.camera);
         camera.setLifecycleOwner(this);
         camera.addCameraListener(new Listener());
+        camera.addFrameProcessor(new FrameProcessor() {
+            private long lastTime = System.currentTimeMillis();
+            @Override
+            public void process(@NonNull Frame frame) {
+                long newTime = frame.getTime();
+                long delay = newTime - lastTime;
+                lastTime = newTime;
+                Log.e("Frames", "Delay: " + delay + "millis, FPS: " + 1000 / delay);
+            }
+        });
 
         findViewById(R.id.edit).setOnClickListener(this);
         findViewById(R.id.capturePicture).setOnClickListener(this);

demo/src/main/res/layout/activity_camera.xml

@@ -17,7 +17,7 @@
         android:layout_marginBottom="88dp"
         android:keepScreenOn="true"
         app:cameraExperimental="true"
-        app:cameraEngine="camera2"
+        app:cameraEngine="camera1"
         app:cameraPreview="glSurface"
         app:cameraPlaySounds="true"
         app:cameraGrid="off"