video.js

 <View>
    <Video source={{uri: video}}   
    ref={(ref) => {
        this.player = ref
    }}                                      // Store reference
    onBuffer={this.onBuffer}                // Callback when remote video is buffering
    onEnd={this.onEnd}                      // Callback when playback finishes
    onError={this.videoError}               // Callback when video cannot be loaded
   style={styles.backgroundVideo} />
</View>

backgroundVideo: {
    width: '100%',
    height: 350,
    top: 0,
   left: 0,
    bottom: 0,
    right: 0,
},