Camera preview image data processing with Android L and Camera2 API

Combining a few answers into a more digestible one because @VP’s answer, while technically clear, is difficult to understand if it’s your first time moving from Camera to Camera2:

Using https://github.com/googlesamples/android-Camera2Basic as a starting point, modify the following:

In createCameraPreviewSession() init a new Surface from mImageReader

Surface mImageSurface = mImageReader.getSurface();

Add that new surface as a output target of your CaptureRequest.Builder variable. Using the Camera2Basic sample, the variable will be mPreviewRequestBuilder

mPreviewRequestBuilder.addTarget(mImageSurface);

Here’s the snippet with the new lines (see my @AngeloS comments):

private void createCameraPreviewSession() {

    try {

        SurfaceTexture texture = mTextureView.getSurfaceTexture();
        assert texture != null;

        // We configure the size of default buffer to be the size of camera preview we want.
        texture.setDefaultBufferSize(mPreviewSize.getWidth(), mPreviewSize.getHeight());

        // This is the output Surface we need to start preview.
        Surface surface = new Surface(texture);

        //@AngeloS - Our new output surface for preview frame data
        Surface mImageSurface = mImageReader.getSurface();

        // We set up a CaptureRequest.Builder with the output Surface.
        mPreviewRequestBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);

        //@AngeloS - Add the new target to our CaptureRequest.Builder
        mPreviewRequestBuilder.addTarget(mImageSurface);

        mPreviewRequestBuilder.addTarget(surface);

        ...

Next, in setUpCameraOutputs(), change the format from ImageFormat.JPEG to ImageFormat.YUV_420_888 when you init your ImageReader. (PS, I also recommend dropping your preview size for smoother operation – one nice feature of Camera2)

mImageReader = ImageReader.newInstance(largest.getWidth() / 16, largest.getHeight() / 16, ImageFormat.YUV_420_888, 2);

Finally, in your onImageAvailable() method of ImageReader.OnImageAvailableListener, be sure to use @Kamala’s suggestion because the preview will stop after a few frames if you don’t close it

    @Override
    public void onImageAvailable(ImageReader reader) {

        Log.d(TAG, "I'm an image frame!");

        Image image =  reader.acquireNextImage();

        ...

        if (image != null)
            image.close();
    }