feat(streaming): 添加自编码串流模式切换功能

webrtc_controller_flutter/lib/webrtc/webrtc_controller.dart

@@ -1,6 +1,8 @@
 import 'package:flutter/foundation.dart';
 import 'package:flutter_webrtc/flutter_webrtc.dart';
 
+import 'self_codec_decoder.dart';
+
 import '../config/ice_servers.dart';
 import '../models/signal_message.dart';
 import '../proto/control_message.pb.dart';
@@ -26,6 +28,10 @@ class WebRtcController {
 
   RTCPeerConnection? _pc;
   RTCDataChannel? _dataChannel;
+  RTCDataChannel? _videoDataChannel;
+  SelfCodecDecoder? _selfCodecDecoder;
+  int _currentStreamMode = streamModeWebRtc;
+  bool _creatingDecoder = false;
 
   /// 远端视频渲染器，由调用方持有并显示。
   final RTCVideoRenderer renderer = RTCVideoRenderer();
@@ -40,6 +46,25 @@ class WebRtcController {
   /// 远端视频流就绪（renderer 已绑定视频轨道）。
   void Function(RTCVideoRenderer renderer)? onRemoteStream;
 
+  /// 自编码解码纹理已就绪（textureId >= 0）。
+  void Function(int)? onSelfCodecReady;
+
+  /// 自编码解码器已释放（连接断开时）。
+  void Function()? onSelfCodecLost;
+
+  /// 被控端上报当前生效的串流模式。
+  void Function(int mode)? onStreamModeReport;
+
+  /// 被控端上报分辨率（自编码解码器输出尺寸变化时也会触发）。
+  void Function(int width, int height)? onResolutionReported;
+
+  /// 当前平台（Windows / Linux / Web / iOS 等）不支持原生硬解时回调。
+  void Function()? onSelfCodecNotSupported;
+
+  static const String kVideoChannelLabel = 'video_channel';
+  static const int streamModeWebRtc = 0;
+  static const int streamModeSelfCodec = 1;
+
   WebRtcController({
     required this.signaling,
     required this.deviceId,
@@ -83,6 +108,17 @@ class WebRtcController {
     _dataChannel = await _pc!.createDataChannel(kDataChannelLabel, dcInit);
     _setupDataChannel(_dataChannel!);
 
+    // 创建自编码视频透传通道（无序、不可靠，类似 RTP，最低延迟）。
+    // 被控端仅在收到 SET_STREAM_MODE=自编码 后才经此通道推送 H.264 裸流。
+    final videoInit = RTCDataChannelInit()
+      ..ordered = false
+      ..maxRetransmits = 0;
+    _videoDataChannel = await _pc!.createDataChannel(
+      kVideoChannelLabel,
+      videoInit,
+    );
+    _setupVideoDataChannel(_videoDataChannel!);
+
     // 创建并发送 Offer。
     final constraints = {
       'mandatory': {
@@ -104,18 +140,22 @@ class WebRtcController {
   }
 
   void _onDataChannel(RTCDataChannel channel) {
-    // 被控端也可能主动创建 DataChannel，统一处理。
-    _setupDataChannel(channel);
+    // 被控端也可能主动创建 DataChannel，按标签统一处理。
+    if (channel.label == kDataChannelLabel) {
+      _dataChannel ??= channel;
+      _setupDataChannel(channel);
+    } else if (channel.label == kVideoChannelLabel) {
+      _videoDataChannel ??= channel;
+      _setupVideoDataChannel(channel);
+    }
   }
 
   void _setupDataChannel(RTCDataChannel channel) {
     channel.onMessage = (RTCDataChannelMessage message) {
-      // 处理来自被控端的消息（本控制端主要发送，此处仅做日志记录）。
       if (message.isBinary) {
         try {
           final command = ControlMessage.fromBuffer(message.binary);
-          // ignore: avoid_print
-          print('DataChannel message: ${command.action}');
+          _handleControlMessage(command);
         } catch (e) {
           // ignore: avoid_print
           print('DataChannel message decode failed: $e');
@@ -131,6 +171,78 @@ class WebRtcController {
     };
   }
 
+  void _setupVideoDataChannel(RTCDataChannel channel) {
+    channel.onMessage = (RTCDataChannelMessage message) {
+      if (message.isBinary) {
+        _selfCodecDecoder?.feed(message.binary);
+      }
+    };
+    channel.onDataChannelState = (RTCDataChannelState state) {
+      if (state == RTCDataChannelState.RTCDataChannelOpen) {
+        _onVideoChannelOpen();
+      } else if (state == RTCDataChannelState.RTCDataChannelClosed) {
+        _selfCodecDecoder?.setEnabled(false);
+      }
+    };
+  }
+
+  void _onVideoChannelOpen() {
+    _ensureSelfCodecDecoder().then((_) {
+      _selfCodecDecoder?.setEnabled(_currentStreamMode == streamModeSelfCodec);
+    });
+  }
+
+  Future<void> _ensureSelfCodecDecoder() async {
+    if (_selfCodecDecoder != null || _creatingDecoder) return;
+    _creatingDecoder = true;
+    try {
+      final decoder = SelfCodecDecoder(
+        onSize: (w, h) => onResolutionReported?.call(w, h),
+        onError: (err) => debugPrint('自编码解码器: $err'),
+      );
+      final textureId = await decoder.create();
+      if (textureId != null) {
+        _selfCodecDecoder = decoder;
+        onSelfCodecReady?.call(textureId);
+      } else {
+        // 当前平台（Windows / Linux / Web / iOS 等）无原生硬解能力，回退 WebRTC 媒体流。
+        onSelfCodecNotSupported?.call();
+      }
+    } finally {
+      _creatingDecoder = false;
+    }
+  }
+
+  void _handleControlMessage(ControlMessage msg) {
+    switch (msg.action) {
+      case Action.REPORT_STREAM_MODE:
+        _currentStreamMode = msg.streamMode;
+        _selfCodecDecoder?.setEnabled(msg.streamMode == streamModeSelfCodec);
+        onStreamModeReport?.call(msg.streamMode);
+        break;
+      case Action.REPORT_RESOLUTION:
+        onResolutionReported?.call(msg.width, msg.height);
+        break;
+      default:
+        // ignore: avoid_print
+        print('DataChannel message: ${msg.action}');
+        break;
+    }
+  }
+
+  /// 请求被控端切换屏幕串流模式（SET_STREAM_MODE 指令）。
+  /// [mode] 为 0=WebRTC 全托管 / 1=自编码。
+  Future<void> sendStreamMode(int mode) async {
+    _currentStreamMode = mode;
+    if (mode == streamModeSelfCodec) {
+      await _ensureSelfCodecDecoder();
+      await _selfCodecDecoder?.setEnabled(true);
+    } else {
+      await _selfCodecDecoder?.setEnabled(false);
+    }
+    sendControlCommand(ControlCommands.streamMode(mode));
+  }
+
   void _onIceCandidate(RTCIceCandidate candidate) {
     final payload = {
       'sdpMid': candidate.sdpMid,
@@ -413,6 +525,20 @@ class WebRtcController {
       await renderer.dispose();
     } catch (_) {}
     _dataChannel = null;
+    try {
+      await _videoDataChannel?.close();
+    } catch (_) {}
+    _videoDataChannel = null;
+    try {
+      await _selfCodecDecoder?.dispose();
+    } catch (_) {}
+    _selfCodecDecoder = null;
+    _currentStreamMode = streamModeWebRtc;
+    onSelfCodecLost?.call();
+    onSelfCodecReady = null;
+    onStreamModeReport = null;
+    onResolutionReported = null;
+    onSelfCodecNotSupported = null;
     _pc = null;
     // 重置网速统计基线，避免下次连接首帧显示错误的瞬时速率。
     _prevBytesReceived = 0;