flutter_gstreamer_player/lib/flutter_gstreamer_player.dart

import 'dart:async';

import 'package:flutter/services.dart';
import 'package:flutter/material.dart';

class GstPlayerTextureController {
  static const MethodChannel _channel = MethodChannel('flutter_gstreamer_player');

  late int textureId;
  static int _id = 0;

  Future<int> initialize(String pipeline) async {
    // No idea why, but you have to increase `_id` first before pass it to method channel,
    // if not, receiver of method channel always received 0
    GstPlayerTextureController._id = GstPlayerTextureController._id + 1;

    textureId = await _channel.invokeMethod('PlayerRegisterTexture', {
      'pipeline': pipeline,
      'playerId': GstPlayerTextureController._id,
    });

    return textureId;
  }

  Future<Null> dispose() {
      return _channel.invokeMethod('dispose', {'textureId': textureId});
  }

  bool get isInitialized => textureId != null;
}

class GstPlayer extends StatefulWidget {
  String pipeline;

  GstPlayer({Key? key, required this.pipeline}) : super(key: key);

  @override
  State<GstPlayer> createState() => _GstPlayerState();
}

class _GstPlayerState extends State<GstPlayer> {
  final _controller = GstPlayerTextureController();

  @override
  void initState() {
    initializeController();
    super.initState();
  }

  @override
  void didUpdateWidget(GstPlayer oldWidget) {
    if (widget.pipeline != oldWidget.pipeline) {
      initializeController();
    }
    super.didUpdateWidget(oldWidget);
  }

  Future<Null> initializeController() async {
    await _controller.initialize(
      widget.pipeline,
    );
    setState(() {});
  }

  @override
  Widget build(BuildContext context) {
    return Container(
      child: _controller.isInitialized
        ? Texture(textureId: _controller.textureId)
        : null,
    );
  }
}