// initialize in application's onCreate
CameraCompat.init(getApplicationContext());

// start preview in your activity or fragment
CameraCompat.Builder builder = new CameraCompat.Builder(this, this)
        .beautifyOn(false)      // default beautify option
        .flashOpen(false)       // default flash option
        .previewWidth(639)      // preview width
        .previewHeight(479)     // preview height
        .enableMirror(false)    // default mirror option
        .frontCamera(false);    // default camera option
if (mBeautifyCapable) {
    // add beautify processor, sorry that BasicBeautifyProcessor doesn't work now,
    // but in our production app, our real beautify processor works well,
    // I'm not an expert about open-gl, pr is welcome!
    builder.addProcessor(new BasicBeautifyProcessor());
}
mCameraCompat = builder.build();
mCameraCompat.startPreview(null,
        getSupportFragmentManager(),
        R.id.mPreviewContainer);    // add this ViewGroup in your layout

@WorkerThread
@Override
public void onVideoSizeChanged(int width, int height) {
    Log.d("PublishActivity", "onVideoSizeChanged width = " + width
                             + ", height = " + height);
}

@WorkerThread
@Override
public void onFrameData(final byte[] data, final int width, final int height) {
    Log.d("PublishActivity", "onFrameData width = " + width
                             + ", height = " + height
                             + ", data length = " + data.length);
}

@WorkerThread
@Override
public void onError(@CameraCompat.ErrorCode int code) {
    runOnUiThread(() ->
            Toast.makeText(this, "@CameraCompat.ErrorCode " + code, Toast.LENGTH_SHORT).show());
}

mCameraCompat.switchBeautify();
mCameraCompat.switchCamera();
mCameraCompat.switchFlash();
mCameraCompat.switchMirror();