MediaCodec input buffer size is small for YUV_420_888 image format

Question

I am using mediaCodec to convert images captured using camera2 api to videos. The problem arrived when I found YV12 isn't supported in some devices. When I used YV12 as input image format, and COLOR_FormatYUV420SemiPlanar as output, the size of input buffer and captured image is exact same. And it works well.

But when I used YUV_420_888 as input image format, the size of image got increased while the size of input buffer is same as before which gave me buffer overflow exception. More specifically, size of input buffer of MediaCodec is always : width * height * 3/2 But size of input image using YUV_420_888 format turns out to be: width * height * 2

I am not sure how to feed this image to mediacodec without causing buffer overflow and without compromising quality.

Any help would be appreciated!

Code for configuring MediaCode

try {
        MediaCodecInfo codecInfo = MediaCodecUtil.selectCodec(MIME_TYPE);
        mediaCodec = MediaCodec.createByCodecName(codecInfo.getName());
        MediaFormat mediaFormat = MediaFormat.createVideoFormat(MIME_TYPE, size.getWidth(), size.getHeight());
        mediaFormat.setInteger(MediaFormat.KEY_BIT_RATE, BIT_RATE);
        mediaFormat.setInteger(MediaFormat.KEY_FRAME_RATE, FRAME_RATE);
        colorFormat = MediaCodecUtil.selectColorFormat(codecInfo, MIME_TYPE);
        mediaFormat.setInteger(MediaFormat.KEY_COLOR_FORMAT, colorFormat);
        mediaFormat.setInteger(MediaFormat.KEY_I_FRAME_INTERVAL, 20);
        mediaCodec.configure(mediaFormat, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE);
        mediaCodec.start();
    } catch (IOException e) {
        e.printStackTrace();
    }

Code for taking image from Camera

try {
        imageSize = CameraUtil.getImageSize(this, currentCameraId);
        ImageReader imageReader = ImageReader.newInstance(imageSize.getWidth(), imageSize.getHeight(), ImageFormat.YUV_420_888, 1);
        imageReaderListener = new ImageReaderListener(this);
        imageReader.setOnImageAvailableListener(imageReaderListener, backgroundHandler);

        List<Surface> outputSurfaces = new ArrayList<>(2);
        outputSurfaces.add(imageReader.getSurface());
        Surface preview = new Surface(textureView.getSurfaceTexture());
        outputSurfaces.add(preview);

        final CaptureRequest.Builder captureBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_RECORD);
        captureBuilder.addTarget(imageReader.getSurface());
        captureBuilder.addTarget(preview);
        captureBuilder.set(CaptureRequest.CONTROL_AF_MODE, CameraMetadata.CONTROL_AF_MODE_CONTINUOUS_PICTURE);
        captureBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON_AUTO_FLASH);

        cameraDevice.createCaptureSession(outputSurfaces,
                new CameraCaptureSession.StateCallback() {
                    @Override
                    public void onConfigured(@NonNull CameraCaptureSession session) {
                        if (cameraDevice == null) {
                            return;
                        }
                        try {
                            mSession = session;
                    session.setRepeatingRequest(captureBuilder.build(), null, backgroundHandler);
                        } catch (CameraAccessException e) {
                            e.printStackTrace();
                        }
                    }

                    @Override
                    public void onConfigureFailed(@NonNull CameraCaptureSession session) {
                        Util.printLogs(CameraActivity.this, TAG, "Capturing picture failed");
                    }
                }, backgroundHandler);
    } catch (Exception e) {
        e.printStackTrace();
    }