Video is Playing but sound is not coming and there is a no method for implementing video controlors

[KasunHasanga]

`import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter/rendering.dart';
import 'package:flutter/widgets.dart';
import 'package:ext_video_player/ext_video_player.dart';

class FirstAidVideo extends StatefulWidget {
@OverRide
_FirstAidVideoState createState() => _FirstAidVideoState();
}

class _FirstAidVideoState extends State {

VideoPlayerController _controller;

void initState() {
super.initState();
controller = VideoPlayerController.network(
'https://www.youtube.com/watch?v=2vpB9IwbjdA')
..initialize().then(() {
// Ensure the first frame is shown after the video is initialized, even before the play button has been pressed.
setState(() {});
});
}
void dispose() {
super.dispose();
_controller.dispose();
}

@OverRide
Widget build(BuildContext context) {

return MaterialApp(
  title: 'Video Demo',
  home: Scaffold(
    body: SingleChildScrollView(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: <Widget>[
          Text('Motivational Video'),
          Container(
            child: _controller.value.initialized
                ? AspectRatio(
              aspectRatio: _controller.value.aspectRatio,
              child: VideoPlayer(_controller),
            )
                : Container(),
          ),
        ],
      ),
    ),
    floatingActionButton: FloatingActionButton(
      onPressed: () {
        setState(() {
          _controller.value.isPlaying
              ? _controller.pause()
              : _controller.play();
        });
      },
      child: Icon(
        _controller.value.isPlaying ? Icons.pause : Icons.play_arrow,
      ),
    ),
  ),
);

`