Android Camera2 API JPEG_QUALITY not available

Question

I am trying to work on my Nexus 5x with android Camera2 APIs and I am using googlesamples android-Camera2Basic

My problem is that the JPEG images have too low quality and their size is much smaller that regular images I am taking with my phone camera app.

According to google documents there should be a key JPEG_QUALITY both in CaptureRequest and in CaptureResult:

JPEG_QUALITY

Added in API level 21

Key JPEG_QUALITY

Compression quality of the final JPEG image.

85-95 is typical usage range.

Range of valid values:

1-100; larger is higher quality

This key is available on all devices.

However when I ask for the available keys, JPEG_QUALITY key is not available so I don't how to know what is my current JPEG compression quallity used and how I can change it.

The code I did inside:

CameraCaptureSession.CaptureCallback CaptureCallback
                = new CameraCaptureSession.CaptureCallback() {

            @Override
            public void onCaptureCompleted(@NonNull CameraCaptureSession session,
                                           @NonNull CaptureRequest request,
                                           @NonNull TotalCaptureResult result) {

               
                //_TEST_DEBUG
                List<CaptureRequest.Key<?>> requestKeys = request.getKeys();
                List<CaptureResult.Key<?>> resultKeys = result.getKeys();

requestKeys & resultKeys have many keys including JPEG_ORIENTATION but not the JPEG_QUALITY key.

Any idea what am I doing wrong? Why can't I find how to change JPEG compression quality?

Thanks, Guy

Answer 1

I achieved increasing the JPEG quality by adding it as a key to the CaptureRequest.Builder in the googlesamples android-Camera2Basic with a Tesco Hudl 2 Tablet on Android 5.1 Lollipop.

The JPEG quality is set in the captureStillPicture() method in the Camer2BasicFragment like so:

        // This is the CaptureRequest.Builder that we use to take a picture.
        final CaptureRequest.Builder captureBuilder =
                mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE);
        captureBuilder.addTarget(mImageReader.getSurface());

        //Set the JPEG quality here like so
        captureBuilder.set(CaptureRequest.JPEG_QUALITY, (byte)90);

I hope this helps.