2025 April 11 Archive - EXEIdeas – Let's Your Mind Rock

How To Implement Live Video Calling In Flutter Apps Without Using Any Third PartyLive video calling has become an essential feature in modern mobile applications. While many developers rely on third-party SDKs like Agora, Twilio, or Zoom, building a custom solution gives you full control over performance, security, and cost. In this guide, we’ll explore how to implement live video calling in Flutter using WebRTC and Firebase—without any external dependencies.Why Build A Custom Video Calling Solution?Before diving into implementation, let’s understand why you might want to avoid third-party services:Cost Efficiency – No per-minute charges or subscription fees.Full Control – Customize UI/UX, security, and features.No Vendor Lock-In – Avoid dependency on external APIs.Better Privacy – Keep user data within your infrastructure.“Building your own video calling solution may seem complex, but with WebRTC and Flutter, it’s entirely achievable without third-party services.”Prerequisites For Flutter Video CallingTo follow this tutorial, ensure you have:Flutter SDK installed (version 3.0 or above)Basic knowledge of Dart and FlutterA Firebase project for signalingPhysical devices or emulators with camera supportUnderstanding The Core TechnologiesWhat Is WebRTC?WebRTC (Web Real-Time Communication) is an open-source project that enables peer-to-peer audio, video, and data sharing directly between browsers and mobile apps. It handles:Media capture (camera & microphone)Encoding/decodingNetwork traversal (STUN/TURN)Secure transmission (DTLS-SRTP)Role Of Firebase In SignalingWebRTC needs a signaling mechanism to exchange session details before establishing a direct connection. Firebase Realtime Database acts as our signaling server to:Exchange SDP (Session Description Protocol) offers/answersShare ICE (Interactive Connectivity Establishment) candidatesManage call states (ringing, connected, ended)Step 1: Setting Up The Flutter ProjectCreate a new Flutter project and add these dependencies in pubspec.yaml: dependencies: flutter_webrtc: ^0.9.0 firebase_core: ^2.0.0 firebase_database: ^10.0.0 permission_handler: ^10.0.0Configuring FirebaseCreate a Firebase project at Firebase ConsoleAdd Android/iOS apps and download configuration filesEnable Realtime Database with test mode rulesStep 2: Implementing WebRTC In FlutterInitializing WebRTC ComponentsCreate a WebRTCService class to manage the video call lifecycle: class WebRTCService { final RTCPeerConnection _peerConnection; final RTCVideoRenderer _localRenderer = RTCVideoRenderer(); final RTCVideoRenderer _remoteRenderer = RTCVideoRenderer(); Future initialize() async { await _localRenderer.initialize(); await _remoteRenderer.initialize(); } Future createPeerConnection() async { _peerConnection = await createPeerConnection({ 'iceServers': [ {'urls': 'stun:stun.l.google.com:19302'}, ] }); } }Handling Media StreamsAdd methods to manage camera access and streams: Future getLocalStream() async { final Map constraints = { 'audio': true, 'video': { 'facingMode': 'user', 'width': {'ideal': 640}, 'height': {'ideal': 480} } }; MediaStream stream = await navigator.mediaDevices.getUserMedia(constraints); _localRenderer.srcObject = stream; return stream; }Step 3: Building The Signaling MechanismFirebase Database StructureDesign your Realtime Database schema for signaling: { "calls": { "callId123": { "caller": "userId1", "callee": "userId2", "offer": { ... }, "answer": { ... }, "iceCandidates": { "candidate1": { ... }, "candidate2": { ... } } } } }Exchanging SDP Offers And AnswersImplement methods to handle signaling: Future createOffer(String callId) async { RTCSessionDescription offer = await _peerConnection.createOffer(); await _peerConnection.setLocalDescription(offer); FirebaseDatabase.instance.ref('calls/$callId').update({ 'offer': offer.toMap(), 'caller': currentUserId, }); } Future handleAnswer(String callId) async { DatabaseReference ref = FirebaseDatabase.instance.ref('calls/$callId'); ref.child('answer').onValue.listen((event) { if (event.snapshot.value != null) { RTCSessionDescription answer = RTCSessionDescription.fromMap(event.snapshot.value); _peerConnection.setRemoteDescription(answer); } }); }Step 4: Establishing The Peer ConnectionICE Candidate ExchangeHandle ICE candidates for network traversal: _peerConnection.onIceCandidate = (RTCIceCandidate candidate) { FirebaseDatabase.instance.ref('calls/$callId/iceCandidates') .push().set(candidate.toMap()); }; void listenForRemoteCandidates(String callId) { FirebaseDatabase.instance.ref('calls/$callId/iceCandidates') .onChildAdded.listen((event) { RTCIceCandidate candidate = RTCIceCandidate.fromMap(event.snapshot.value); _peerConnection.addIceCandidate(candidate); }); }Managing Call StatesImplement call state management:Call Initiation – User creates offerCall Acceptance – Callee creates answerCall Rejection – Clean up resourcesCall Termination – Close peer connectionStep 5: Building The User InterfaceVideo Renderer WidgetsCreate a widget to display video streams: class VideoView extends StatelessWidget { final RTCVideoRenderer renderer; const VideoView({required this.renderer}); @override Widget build(BuildContext context) { return RTCVideoView(renderer); } }Call ControlsAdd essential call controls: Row( mainAxisAlignment: MainAxisAlignment.center, children: [ IconButton( icon: Icon(Icons.mic_off), onPressed: toggleMute, ), IconButton( icon: Icon(Icons.videocam_off), onPressed: toggleVideo, ), IconButton( icon: Icon(Icons.call_end), onPressed: endCall, color: Colors.red, ), ], )Optimizing Performance And ReliabilityBandwidth ManagementAdjust video quality based on network conditions: void adaptVideoQuality(NetworkQuality quality) { final constraints = { 'video': { 'width': quality == NetworkQuality.Poor ? 320 : 640, 'height': quality == NetworkQuality.Poor ? 240 : 480, 'frameRate': quality == NetworkQuality.Poor ? 15 : 30 } }; _peerConnection.getSenders()[1].setParameters(constraints); }Error Handling And ReconnectionImplement robust error recovery:Monitor connection state changesImplement ICE restart on failureAdd timeout for signaling exchangesProvide user feedback on connection issuesConclusionBuilding a live video calling feature in Flutter without third-party services gives you complete control over the user experience while reducing costs. By leveraging WebRTC for peer-to-peer communication and Firebase for signaling, you can create a fully functional video calling system. While this approach requires more initial setup compared to SDKs like Agora or Twilio, the long-term benefits in customization and cost savings make it worthwhile for many applications.Remember to test extensively across different network conditions and devices. Consider adding features like call recording, screen sharing, or text chat to enhance your video calling solution further.