Android 5.0 Wrong crop regions on preview surface

问题:

I'm trying to get digital zoomed frame on Android 5.0 with camera2 interface. Appropriate doc for that functionality is developer.android.com/camera2/captureRequest

Surface used in my application:

• SurafaceView (1920x1080, 16:9 aspect ratio)
• ImageReader (3264x2448, 4:3 aspect ratio)

Camera's sensor size is 3280x2464 (4:3 aspect ratio)

Crop region which I want to get from sensor is:

Rect zoomCropPreview = new Rect(1094, 822, 2186, 1642); //(1092x820, 4:3 aspect ratio)

I set this Rect as parameter for preview request:

previewRequestBuilder.set(CaptureRequest.SCALER_CROP_REGION, zoomCropPreview);
captureSession.setRepeatingRequest(previewRequestBuilder.build(), null, null);

And to take still image:

stillRequestBuilder.set(CaptureRequest.SCALER_CROP_REGION, zoomCropPreview);

captureSession.capture(stillRequestBuilder.build(), new captureListener() , null);

Expected results:

• Coz crop rectangle is 4:3 ratio, then preview should be cropped vertically (letterbox)
• Still image should be exact crop region.
• Both preview and still image should be centered on the same point of scene, and should differ only in vertical edges.

Real result:

• Preview and still image point on different scene which seems to be moved vertically. Look at attach images.

What am I doing wrong?

回答1:

Fixed! General idea is to calculate crop region for preview and still images separately.

1) Calculate crop region for still image as in initial post (use 4:3 rectangle)

2) For preview take above crop region (4:3) and reduce vertical size to get 16:9 rectangle.