How to map getFrameNumber of CameraResult for Image receive from ImageReader Camera2

Question

I need getFrameNumber for Image object received from ImageReader for my camera2.

Currently, I received different timestamp for the following code so due to that, I am not able to map getFrameNumber of CameraResult callback.

 CameraCaptureSession.CaptureCallback captureListenerLeft = new CameraCaptureSession.CaptureCallback() {
        @Override
        public void onCaptureCompleted(CameraCaptureSession session, CaptureRequest request, TotalCaptureResult result) {
            super.onCaptureCompleted(session, request, result);

                Log.d(TAG, "#### Camera Preview: FrameNumber:[" + result.getFrameNumber()+"] TimeStamp:[" + result.get(CaptureResult.SENSOR_TIMESTAMP) / 1000000 + "] Expo:[" +result.get(CaptureResult.SENSOR_EXPOSURE_TIME)+ "] FrameDuration:[" + result.get(CaptureResult.SENSOR_FRAME_DURATION) + "]");

        }
    };

Now at ImageReader Callback:-

ImageReader.OnImageAvailableListener mImgLeftCameraListener=new ImageReader.OnImageAvailableListener() {
        @Override
        public void onImageAvailable(ImageReader imageReader) {

            try{
                Image mImage=imageReader.acquireNextImage();
                long mTimeStap=mImage.getTimestamp()/1000000;              
                mImage.close();
            }catch (Exception exc){

                exc.printStackTrace();
            }

        }
    };

Now the issue is Image reader mTimeStap does not match with result.get(CaptureResult.SENSOR_TIMESTAMP) / 1000000 value, So i am not able to map getFrameNumber.

NOTE: My android is 7.1.1 custom OS build for Qualcomm 820.

Answer 1

The timestamps are the only way to match these; by design of the API, they should match. What kinds of differences are you seeing in the timestamp values?

Edit: And to add, there's no way to get a frame number from the image reader; that value is not passed to the ImageReader at all.