Unable to add overlay on react-native Expo Camera recordings

Question

Why I cannot add an overlay on Expo Camera?

I tried adding an Text 'Hello' (Like a water mark) in below example. Now, I can see that on my app, however, when I save the recording and check that video, I don't see that text 'Hello' appears at all.

How can I fix that??

        <Camera
          style={{
            flex: 1,
            width: "100%",
          }}
          type={camType}
          ref={cameraRef}
          autoFocus={AutoFocus.on}
          ratio={'1:1'}
          videoStabilizationMode={VideoStabilization.auto}
          >
          <Text style={{ backgroundColor: 'green', justifyContent: "center", textAlign: "center", top: 50}}>Hello</Text>

        </Camera>