getRotationDegrees is different on imageCapture and imageAnalysis on device

Question

I have the same code for imageAnalysis and for imageCapture. But I get different getRotationDegrees.

        ImageAnalysis imageAnalysis = new ImageAnalysis.Builder()
                .setTargetResolution(new Size(1200,720 ))
                .setBackpressureStrategy(ImageAnalysis.STRATEGY_KEEP_ONLY_LATEST)
                .setOutputImageFormat(ImageAnalysis.OUTPUT_IMAGE_FORMAT_YUV_420_888)
                .setTargetRotation(rotation)
                .build();

        imageAnalysis.setAnalyzer(executor, image -> {
               imageRotationDegrees = image.getImageInfo().getRotationDegrees(); 

and

   // Create image capture
    imageCapture = new ImageCapture.Builder()
                .setTargetRotation(rotation)
                .build();

    public void takePicture() {
        imageCapture.takePicture(getExecutor(), new ImageCapture.OnImageCapturedCallback() {
            @Override
            public void onCaptureSuccess(@NonNull ImageProxy image) {

                imageRotationDegrees = image.getImageInfo().getRotationDegrees();

On Emulator:

imageRotationDegrees = 90 in imageAnalisys;

imageRotationDegrees = 90 in imageCapture;

On Device:

imageRotationDegrees = 90 in imageAnalisys;

imageRotationDegrees = 0 in imageCapture;

I cant understand why RotationDegrees are different between capture modes.

Answer 1

It's because the ImageCapture output is rotated by CameraX, while the ImageAnalysis is not.

The rotationDegrees represents how the app should rotate the image to get it "upright". The original image usually needs rotation, that is why ImageAnalysis output has a rotation degrees.

For ImageCapture, some OEMs choose to rotate the output in the hardware layer for efficiency. If the image is already rotated, then there is no need for the app to rotate, thus the rotation degree becomes 0.