video_decode_plugin/example/lib/main.dart

import 'dart:async';
import 'dart:io';
import 'dart:typed_data';
import 'dart:math' as math;

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

// 用于存储H264文件中解析出的帧
class H264Frame {
  final Uint8List data;
  final FrameType type;

  H264Frame(this.data, this.type);
}

// H264 NAL 单元类型
class NalUnitType {
  static const int UNSPECIFIED = 0;
  static const int CODED_SLICE_NON_IDR = 1; // P帧
  static const int PARTITION_A = 2;
  static const int PARTITION_B = 3;
  static const int PARTITION_C = 4;
  static const int CODED_SLICE_IDR = 5; // I帧
  static const int SEI = 6; // 补充增强信息
  static const int SPS = 7; // 序列参数集
  static const int PPS = 8; // 图像参数集
  static const int AUD = 9; // 访问单元分隔符
  static const int END_SEQUENCE = 10; // 序列结束
  static const int END_STREAM = 11; // 码流结束
  static const int FILLER_DATA = 12; // 填充数据
  static const int SPS_EXT = 13; // SPS扩展
  static const int PREFIX_NAL = 14; // 前缀NAL单元
  static const int SUBSET_SPS = 15; // 子集SPS
  static const int DEPTH_PARAM_SET = 16; // 深度参数集
  static const int RESERVED_17 = 17; // 保留类型
  static const int RESERVED_18 = 18; // 保留类型
  static const int CODED_SLICE_AUX = 19; // 辅助切片
  static const int CODED_SLICE_EXTENSION = 20; // 扩展切片
  static const int CODED_SLICE_DEPTH = 21; // 深度扩展
  static const int RESERVED_22 = 22; // 保留类型
  static const int RESERVED_23 = 23; // 保留类型
  static const int STAP_A = 24; // 单时间聚合包A
  static const int STAP_B = 25; // 单时间聚合包B
  static const int MTAP_16 = 26; // 多时间聚合包16
  static const int MTAP_24 = 27; // 多时间聚合包24
  static const int FU_A = 28; // 分片单元A
  static const int FU_B = 29; // 分片单元B
  static const int RESERVED_30 = 30; // 保留类型
  static const int RESERVED_31 = 31; // 保留类型

  // 帧类型别名，方便调用
  static const int NON_IDR_PICTURE = CODED_SLICE_NON_IDR; // P帧
  static const int IDR_PICTURE = CODED_SLICE_IDR; // I帧

  // 获取类型名称
  static String getName(int type) {
    switch (type) {
      case UNSPECIFIED:
        return "未指定";
      case CODED_SLICE_NON_IDR:
        return "P帧";
      case PARTITION_A:
        return "分区A";
      case PARTITION_B:
        return "分区B";
      case PARTITION_C:
        return "分区C";
      case CODED_SLICE_IDR:
        return "I帧";
      case SEI:
        return "SEI";
      case SPS:
        return "SPS";
      case PPS:
        return "PPS";
      case AUD:
        return "AUD";
      case END_SEQUENCE:
        return "序列结束";
      case END_STREAM:
        return "码流结束";
      case FILLER_DATA:
        return "填充数据";
      case SPS_EXT:
        return "SPS扩展";
      case PREFIX_NAL:
        return "前缀NAL";
      case SUBSET_SPS:
        return "子集SPS";
      case CODED_SLICE_AUX:
        return "辅助切片";
      case CODED_SLICE_EXTENSION:
        return "扩展切片";
      case FU_A:
        return "分片单元A";
      case FU_B:
        return "分片单元B";
      default:
        return "未知($type)";
    }
  }
}

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: '视频解码演示',
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
        useMaterial3: true,
      ),
      home: const VideoView(),
    );
  }
}

class VideoView extends StatefulWidget {
  const VideoView({Key? key}) : super(key: key);

  @override
  State<VideoView> createState() => _VideoViewState();
}

class _VideoViewState extends State<VideoView> {
  // 解码器状态
  int? _textureId;
  bool _isInitialized = false;
  bool _isPlaying = false;
  String _statusText = "未初始化";
  String _error = "";

  // 解码器状态信息
  DecoderState _decoderState = DecoderState.initializing;
  String _decoderStateText = "初始化中";
  bool _isActuallyRendering = false; // 区分预通知和实际渲染状态

  // 帧统计
  int _renderedFrameCount = 0;
  DateTime? _lastFrameTime;
  double _fps = 0;
  double _decoderFps = 0; // 解码器内部计算的FPS

  // 用于刷新解码器统计信息的定时器
  Timer? _statsTimer;

  // 丢包模拟相关
  bool _enablePacketLoss = false;
  double _packetLossRate = 0.1; // 默认10%丢包率
  bool _dropIFrames = false;
  bool _dropPFrames = false;
  bool _dropSPSPPS = false;
  bool _burstPacketLossMode = false;
  int _burstPacketLossCounter = 0;
  int _droppedFramesCount = 0;

  // H264文件解析
  Uint8List? _h264FileData;
  List<H264Frame> _h264Frames = [];
  int _currentFrameIndex = 0;

  // 解码定时器
  Timer? _frameTimer;

  // 日志
  final List<String> _logs = [];
  final ScrollController _logScrollController = ScrollController();

  // 视频显示相关的属性
  bool _showingErrorFrame = false;
  Timer? _errorFrameResetTimer;

  // 额外的解码器属性
  int _totalFrames = 0;
  int _droppedFrames = 0;
  bool _hasSentIDR = false;
  bool _hasSentSPS = false;
  bool _hasSentPPS = false;

  @override
  void initState() {
    super.initState();
    _loadH264File();

    // 仅在需要时使用定时器更新一些UI元素
    _statsTimer = Timer.periodic(Duration(milliseconds: 1000), (timer) {
      if (mounted) {
        setState(() {
          // 更新UI元素，例如帧率计算等
          // 解码器统计信息现在通过回调获取，不需要在这里请求
        });
      }
    });
  }

  @override
  void dispose() {
    _stopPlaying();
    _releaseDecoder();
    _frameTimer?.cancel();
    _statsTimer?.cancel();
    super.dispose();
  }

  // 加载H264文件
  Future<void> _loadH264File() async {
    try {
      _log("正在加载 demo.h264 文件...");
      final ByteData data = await rootBundle.load('assets/demo.h264');
      setState(() {
        _h264FileData = data.buffer.asUint8List();
      });
      _log("H264文件加载完成: ${_h264FileData!.length} 字节");

      // 解析H264文件
      _parseH264File();
    } catch (e) {
      _log("加载H264文件失败: $e");
      setState(() {
        _error = "加载H264文件失败: $e";
      });
    }
  }

  // 解析H264文件，提取NAL单元
  void _parseH264File() {
    if (_h264FileData == null) return;

    _log("开始解析H264文件...");

    List<H264Frame> frames = [];

    // 查找起始码 0x00000001 或 0x000001
    int startIndex = 0;
    bool hasSps = false;
    bool hasPps = false;

    while (startIndex < _h264FileData!.length - 4) {
      // 查找下一个起始码
      int nextStartIndex = _findStartCode(_h264FileData!, startIndex + 3);
      if (nextStartIndex == -1) {
        nextStartIndex = _h264FileData!.length;
      }

      // 提取NAL单元，跳过起始码（3或4字节）
      int skipBytes = (_h264FileData![startIndex] == 0x00 &&
              _h264FileData![startIndex + 1] == 0x00 &&
              _h264FileData![startIndex + 2] == 0x00 &&
              _h264FileData![startIndex + 3] == 0x01)
          ? 4
          : 3;

      if (nextStartIndex > startIndex + skipBytes) {
        // 获取NAL类型
        int nalType = _h264FileData![startIndex + skipBytes] & 0x1F;

        // 创建NAL单元数据
        var nalData = Uint8List(nextStartIndex - startIndex);
        for (int i = 0; i < nalData.length; i++) {
          nalData[i] = _h264FileData![startIndex + i];
        }

        // 根据NAL类型分类
        switch (nalType) {
          case NalUnitType.SPS:
            _log("找到SPS: 位置=${startIndex}, 长度=${nalData.length}");
            hasSps = true;
            frames.add(H264Frame(nalData, FrameType.iFrame));
            break;
          case NalUnitType.PPS:
            _log("找到PPS: 位置=${startIndex}, 长度=${nalData.length}");
            hasPps = true;
            frames.add(H264Frame(nalData, FrameType.iFrame));
            break;
          case NalUnitType.CODED_SLICE_IDR:
            _log("找到I帧: 位置=${startIndex}, 长度=${nalData.length}");
            frames.add(H264Frame(nalData, FrameType.iFrame));
            break;
          case NalUnitType.CODED_SLICE_NON_IDR:
            frames.add(H264Frame(nalData, FrameType.pFrame));
            break;
          default:
            // 其他类型的NAL单元也添加进去
            frames.add(H264Frame(nalData, FrameType.pFrame));
            break;
        }
      }

      startIndex = nextStartIndex;
    }

    setState(() {
      _h264Frames = frames;
    });

    _log("H264文件解析完成，找到 ${frames.length} 个帧，包含SPS=${hasSps}, PPS=${hasPps}");
  }

  // 查找起始码的辅助方法
  int _findStartCode(Uint8List data, int offset) {
    for (int i = offset; i < data.length - 3; i++) {
      // 检查是否为0x000001
      if (data[i] == 0x00 && data[i + 1] == 0x00 && data[i + 2] == 0x01) {
        return i;
      }
      // 检查是否为0x00000001
      if (i < data.length - 4 &&
          data[i] == 0x00 &&
          data[i + 1] == 0x00 &&
          data[i + 2] == 0x00 &&
          data[i + 3] == 0x01) {
        return i;
      }
    }
    return -1;
  }

  // 获取NAL类型
  // 获取NAL类型
  int _getNalType(Uint8List data) {
    // 跳过起始码后再获取NAL单元类型
    if (data.length > 4) {
      // 检查是否有0x00000001的起始码
      if (data[0] == 0x00 &&
          data[1] == 0x00 &&
          data[2] == 0x00 &&
          data[3] == 0x01) {
        // 起始码后的第一个字节的低5位是NAL类型
        if (data.length > 4) {
          return data[4] & 0x1F;
        }
      }
      // 检查是否有0x000001的起始码
      else if (data[0] == 0x00 && data[1] == 0x00 && data[2] == 0x01) {
        // 起始码后的第一个字节的低5位是NAL类型
        if (data.length > 3) {
          return data[3] & 0x1F;
        }
      }
    }

    // 如果找不到起始码或数据不足，则尝试直接获取
    if (data.length > 0) {
      return data[0] & 0x1F;
    }
    return 0;
  }

  // 当新帧可用时调用
  void _onFrameAvailable(int textureId) {
    if (!mounted) return;

    _log("收到帧回调 - 渲染帧 ${_renderedFrameCount + 1}");

    // 更新帧时间用于FPS计算
    _lastFrameTime = DateTime.now();

    // 立即更新UI以显示新帧
    setState(() {
      _renderedFrameCount++;
    });
  }

  Future<void> _initializeDecoder() async {
    if (_isInitialized) {
      await _releaseDecoder();
    }

    _log("正在初始化解码器");

    try {
      final config = VideoDecoderConfig(
        width: 640,
        height: 480,
        codecType: CodecType.h264,
        frameRate: 24, // 设置为接近原视频的24fps (23.976)
        isDebug: true, // 打开调试日志
      );

      final textureId = await VideoDecodePlugin.initDecoder(config);

      if (textureId != null) {
        _textureId = textureId;

        // 设置帧回调
        VideoDecodePlugin.setFrameCallbackForTexture(
            textureId, _onFrameAvailable);

        // 设置状态回调
        VideoDecodePlugin.setStateCallbackForTexture(
            textureId, _onDecoderStateChanged);

        setState(() {
          _isInitialized = true;
          _error = "";
          _statusText = "就绪";
          _renderedFrameCount = 0; // 重置帧计数
          _decoderState = DecoderState.initializing;
          _decoderStateText = "初始化中";
          _isActuallyRendering = false;
        });

        _log("解码器初始化成功，纹理ID: $_textureId");

        // 自动发送测试帧以触发渲染
        await _sendTestIFrame();
      } else {
        setState(() {
          _error = "获取纹理ID失败";
          _statusText = "初始化失败";
        });
        _log("解码器初始化失败 - 返回空纹理ID");
      }
    } catch (e) {
      setState(() {
        _error = e.toString();
        _statusText = "初始化错误";
      });
      _log("解码器初始化错误: $e");
    }
  }

  // 解码器状态变化回调
  void _onDecoderStateChanged(
      int textureId, DecoderState state, Map<String, dynamic> stats) {
    if (!mounted) return;

    String stateText;
    switch (state) {
      case DecoderState.initializing:
        stateText = "初始化中";
        break;
      case DecoderState.ready:
        stateText = "准备就绪";
        break;
      case DecoderState.rendering:
        stateText = "渲染中";
        // 标记实际渲染状态
        _isActuallyRendering = true;
        break;
      case DecoderState.error:
        stateText = "出错";
        // 获取错误信息
        final errorMessage = stats['errorMessage'] as String?;
        if (errorMessage != null) {
          _log("解码器错误: $errorMessage");
        }
        break;
      case DecoderState.released:
        stateText = "已释放";
        break;
      default:
        stateText = "未知状态";
    }

    // 更新解码器状态UI
    setState(() {
      _decoderState = state;
      _decoderStateText = stateText;

      // 更新统计信息
      if (stats.isNotEmpty) {
        _decoderFps = (stats['fps'] as num?)?.toDouble() ?? 0.0;
        _renderedFrameCount = (stats['renderedFrames'] as int?) ?? 0;

        // 更新更多统计信息
        _totalFrames = (stats['totalFrames'] as int?) ?? 0;
        _droppedFrames = (stats['droppedFrames'] as int?) ?? 0;
        _hasSentIDR = (stats['hasSentIDR'] as bool?) ?? false;
        _hasSentSPS = (stats['hasSentSPS'] as bool?) ?? false;
        _hasSentPPS = (stats['hasSentPPS'] as bool?) ?? false;

        // 更新状态文本
        if (state == DecoderState.rendering) {
          _statusText = _isPlaying
              ? "播放中 (解码总帧: $_totalFrames, 丢弃: $_droppedFrames)"
              : "已停止";
        }
      }
    });

    String decoderInfo = "解码器状态更新: $_decoderStateText, " +
        "帧数据: 渲染=$_renderedFrameCount, 总计=$_totalFrames, 丢弃=$_droppedFrames, " +
        "FPS=${_decoderFps.toStringAsFixed(1)}, " +
        "参数集: SPS=${_hasSentSPS}, PPS=${_hasSentPPS}, IDR=${_hasSentIDR}";

    _log(decoderInfo);
  }

  // 添加一个测试I帧来触发渲染
  Future<void> _sendTestIFrame() async {
    if (_textureId == null || !_isInitialized) {
      _log("解码器未准备好，无法发送测试帧");
      return;
    }

    _log("生成并发送测试I帧");

    // 创建一个简单的NAL单元 (IDR帧)
    // 5字节的起始码 + NAL类型5(I帧) + 一些简单的数据
    List<int> testFrameData = [
      0x00, 0x00, 0x00, 0x01, 0x65, // 起始码 + NAL类型 (0x65 = 101|0101 -> 类型5)
      0x88, 0x84, 0x21, 0x43, 0x14, 0x56, 0x32, 0x80 // 一些随机数据
    ];

    Uint8List testFrame = Uint8List.fromList(testFrameData);

    try {
      _log("发送测试I帧: ${testFrame.length} 字节");

      bool success = await VideoDecodePlugin.decodeFrameForTexture(
          _textureId!, testFrame, FrameType.iFrame);

      _log("测试I帧发送结果: ${success ? '成功' : '失败'}");
    } catch (e) {
      _log("发送测试帧错误: $e");
    }
  }

  Future<void> _releaseDecoder() async {
    _statsTimer?.cancel(); // 取消统计信息定时器
    if (_textureId != null) {
      _log("正在释放解码器资源");

      try {
        await VideoDecodePlugin.releaseDecoderForTexture(_textureId!);

        setState(() {
          _textureId = null;
          _isInitialized = false;
          _statusText = "已释放";
          _isActuallyRendering = false;
          _decoderState = DecoderState.released;
          _decoderStateText = "已释放";
        });

        _log("解码器资源释放成功");
      } catch (e) {
        _log("释放解码器错误: $e");
      }
    }
  }

  Future<void> _startPlaying() async {
    if (!_isInitialized || _isPlaying || _h264Frames.isEmpty) {
      _log(
          "播放条件未满足: 初始化=${_isInitialized}, 播放中=${_isPlaying}, 帧数量=${_h264Frames.length}");
      return;
    }

    _log("开始播放H264视频");

    try {
      // 重置帧率跟踪
      _renderedFrameCount = 0;
      _lastFrameTime = null;
      _fps = 0;
      _currentFrameIndex = 0;

      // 确保首先发送SPS和PPS
      await _sendSpsAndPps();

      // 开始解码帧
      _startDecodingFrames();

      setState(() {
        _isPlaying = true;
        _statusText = "播放中";
      });

      _log("播放已开始");
    } catch (e) {
      _log("播放开始错误: $e");
    }
  }

  // 发送SPS和PPS
  Future<void> _sendSpsAndPps() async {
    for (int i = 0; i < math.min(10, _h264Frames.length); i++) {
      H264Frame frame = _h264Frames[i];

      // 检查是否是SPS或PPS (通过检查NAL类型)
      if (frame.data.length > 4) {
        int skipBytes = (frame.data[0] == 0x00 &&
                frame.data[1] == 0x00 &&
                frame.data[2] == 0x00 &&
                frame.data[3] == 0x01)
            ? 4
            : 3;

        if (skipBytes < frame.data.length) {
          int nalType = frame.data[skipBytes] & 0x1F;

          if (nalType == NalUnitType.SPS || nalType == NalUnitType.PPS) {
            _log("发送${nalType == NalUnitType.SPS ? 'SPS' : 'PPS'}数据");
            await _decodeNextFrame(frame);
            // 发送后等待一小段时间，确保解码器处理
            await Future.delayed(Duration(milliseconds: 30));
          }
        }
      }
    }
  }

  void _stopPlaying() {
    if (!_isPlaying) return;

    _log("停止播放");

    _frameTimer?.cancel();
    _frameTimer = null;

    setState(() {
      _isPlaying = false;
      _statusText = "已停止";
    });

    _log("播放已停止");
  }

  void _startDecodingFrames() {
    _log("开始解码视频帧");

    // 使用与原视频接近的帧率
    const int frameIntervalMs = 42; // 约23.8 fps (接近原视频23.9fps)

    _frameTimer =
        Timer.periodic(Duration(milliseconds: frameIntervalMs), (timer) async {
      if (_currentFrameIndex >= _h264Frames.length) {
        _log("所有帧已解码，重新开始");
        _currentFrameIndex = 0;

        // 重新发送SPS和PPS
        await _sendSpsAndPps();
      }

      final frame = _h264Frames[_currentFrameIndex];
      bool decodeSuccess = await _decodeNextFrame(frame);

      // 只有在成功解码的情况下才显示日志信息
      if (!decodeSuccess && _enablePacketLoss) {
        _log("跳过索引 $_currentFrameIndex 的帧（丢帧模拟）");
      }

      // 无论解码是否成功，都移动到下一帧
      _currentFrameIndex++;
    });
  }

  Future<bool> _decodeNextFrame(H264Frame frame) async {
    if (_textureId == null || !_isInitialized || !_isPlaying) {
      return false;
    }

    try {
      // 获取NAL类型
      int nalType = _getNalType(frame.data);

      // 模拟丢包
      if (_enablePacketLoss) {
        bool shouldDrop = false;

        // 爆发式丢包模式
        if (_burstPacketLossMode && _burstPacketLossCounter > 0) {
          shouldDrop = true;
          _burstPacketLossCounter--;
        }
        // 随机丢包
        else if (math.Random().nextDouble() < _packetLossRate) {
          shouldDrop = true;

          // 触发爆发式丢包
          if (_burstPacketLossMode) {
            _burstPacketLossCounter = math.Random().nextInt(5) + 1; // 随机爆发1-5个包
          }
        }

        // 特定类型NAL的丢包策略
        if (nalType == NalUnitType.CODED_SLICE_IDR && _dropIFrames) {
          shouldDrop = true;
        } else if ((nalType == NalUnitType.CODED_SLICE_NON_IDR ||
                nalType == NalUnitType.CODED_SLICE_EXTENSION) &&
            _dropPFrames) {
          shouldDrop = true;
        } else if ((nalType == NalUnitType.SPS || nalType == NalUnitType.PPS) &&
            _dropSPSPPS) {
          shouldDrop = true;
        }

        if (shouldDrop) {
          _droppedFramesCount++;
          String nalTypeName = NalUnitType.getName(nalType);
          _log("丢弃帧：NAL类型 = $nalTypeName");

          // 显示丢帧效果
          setState(() {
            _showingErrorFrame = true;
          });

          // 1秒后重置丢帧效果指示器
          _errorFrameResetTimer?.cancel();
          _errorFrameResetTimer = Timer(Duration(milliseconds: 1000), () {
            if (mounted) {
              setState(() {
                _showingErrorFrame = false;
              });
            }
          });

          return false; // 直接返回false，不进行解码
        }
      }

      // 解码帧
      final success = await VideoDecodePlugin.decodeFrameForTexture(
        _textureId!,
        frame.data,
        frame.type,
      );

      if (!success) {
        _log("解码帧失败，索引 $_currentFrameIndex (${frame.type})");
      } else {
        String nalTypeName = NalUnitType.getName(nalType);
        _log(
            "解码帧成功，索引 $_currentFrameIndex (${frame.type}), NAL类型: $nalTypeName");
      }
      return success;
    } catch (e) {
      _log("解码帧错误: $e");
      return false;
    }
  }

  void _log(String message) {
    final timestamp = DateTime.now().toString().split('.').first;
    final logMessage = "[$timestamp] $message";

    setState(() {
      _logs.add(logMessage);
      if (_logs.length > 100) {
        _logs.removeAt(0);
      }
    });

    // 滚动到底部
    WidgetsBinding.instance.addPostFrameCallback((_) {
      if (_logScrollController.hasClients) {
        _logScrollController.animateTo(
          _logScrollController.position.maxScrollExtent,
          duration: Duration(milliseconds: 200),
          curve: Curves.easeOut,
        );
      }
    });
  }

  Widget _buildVideoDisplay() {
    if (_textureId == null) {
      return Container(
        width: 640,
        height: 480,
        color: Colors.black54,
        child: Center(
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              Icon(Icons.videocam_off, size: 48, color: Colors.white70),
              SizedBox(height: 16),
              Text(
                '无可用纹理',
                style: TextStyle(color: Colors.white, fontSize: 16),
              ),
            ],
          ),
        ),
      );
    }

    return Stack(
      fit: StackFit.expand,
      children: [
        // 背景色
        Container(color: Colors.black),

        // 无帧时显示加载指示
        if (_renderedFrameCount == 0 || !_isActuallyRendering)
          Center(
            child: Column(
              mainAxisSize: MainAxisSize.min,
              children: [
                CircularProgressIndicator(
                  valueColor: AlwaysStoppedAnimation<Color>(Colors.white70),
                ),
                SizedBox(height: 16),
                Text(
                  _decoderState == DecoderState.initializing
                      ? '初始化中...'
                      : _decoderState == DecoderState.ready
                          ? '准备就绪，等待首帧...'
                          : '加载中...',
                  style: TextStyle(color: Colors.white70, fontSize: 14),
                ),
              ],
            ),
          ),

        // 视频纹理 - 使用RepaintBoundary和ValueKey确保正确更新
        RepaintBoundary(
          child: Texture(
            textureId: _textureId!,
            filterQuality: FilterQuality.medium,
            key: ValueKey('texture_${_renderedFrameCount}'),
          ),
        ),

        // 丢包效果指示器 - 当有帧被丢弃时，上方显示红色条带
        if (_enablePacketLoss && _droppedFramesCount > 0)
          Positioned(
            top: 0,
            left: 0,
            right: 0,
            height: 5,
            child: Container(
              color: Colors.red.withOpacity(0.8),
            ),
          ),

        // 解码器状态指示
        if (_decoderState == DecoderState.error)
          Container(
            color: Colors.red.withOpacity(0.3),
            child: Center(
              child: Column(
                mainAxisSize: MainAxisSize.min,
                children: [
                  Icon(Icons.error_outline, size: 48, color: Colors.white),
                  SizedBox(height: 16),
                  Text(
                    '解码器错误',
                    style: TextStyle(
                        color: Colors.white,
                        fontSize: 16,
                        fontWeight: FontWeight.bold),
                  ),
                ],
              ),
            ),
          ),

        // 显示帧计数 - 调试用
        Positioned(
          right: 10,
          top: 10,
          child: Container(
            padding: EdgeInsets.all(5),
            decoration: BoxDecoration(
              color: Colors.black.withOpacity(0.5),
              borderRadius: BorderRadius.circular(4),
            ),
            constraints: BoxConstraints(
              maxWidth: 150, // 限制最大宽度
            ),
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.end,
              mainAxisSize: MainAxisSize.min, // 确保column只占用所需空间
              children: [
                Text(
                  '帧: $_renderedFrameCount',
                  style: TextStyle(color: Colors.white, fontSize: 12),
                ),
                if (_enablePacketLoss)
                  Text(
                    '丢帧: $_droppedFramesCount',
                    style: TextStyle(
                      color: _droppedFramesCount > 0
                          ? Colors.orange
                          : Colors.white70,
                      fontSize: 12,
                    ),
                  ),
              ],
            ),
          ),
        ),
      ],
    );
  }

  @override
  Widget build(BuildContext context) {
    // 更新FPS计算
    if (_lastFrameTime != null && _renderedFrameCount > 0) {
      final now = DateTime.now();
      final elapsed = now.difference(_lastFrameTime!).inMilliseconds;
      if (elapsed > 0) {
        _fps = 1000 / elapsed;
      }
    }

    return Scaffold(
      appBar: AppBar(
        title: Text('视频解码插件演示'),
        backgroundColor: Theme.of(context).colorScheme.primaryContainer,
      ),
      body: SafeArea(
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: [
            // 视频显示区域 - 使用AspectRatio控制大小
            AspectRatio(
              aspectRatio: 16 / 9,
              child: Container(
                decoration: BoxDecoration(
                  border: Border.all(color: Colors.grey),
                ),
                child: _buildVideoDisplay(),
              ),
            ),

            // 控制面板和状态信息 - 使用Expanded和SingleChildScrollView
            Expanded(
              child: Padding(
                padding: const EdgeInsets.all(8.0),
                child: SingleChildScrollView(
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.stretch,
                    children: [
                      // 状态信息区 - 使用Card使其更紧凑
                      Card(
                        child: Padding(
                          padding: const EdgeInsets.all(8.0),
                          child: Column(
                            crossAxisAlignment: CrossAxisAlignment.start,
                            children: [
                              // 状态行
                              Text('状态: $_statusText',
                                  style:
                                      TextStyle(fontWeight: FontWeight.bold)),

                              // 解码器状态行
                              Padding(
                                padding: const EdgeInsets.only(top: 4.0),
                                child: Text(
                                  '解码器状态: $_decoderStateText',
                                  style: TextStyle(
                                      color: _getStateColor(),
                                      fontWeight: FontWeight.bold),
                                ),
                              ),

                              // 实际渲染状态
                              Padding(
                                padding: const EdgeInsets.only(top: 4.0),
                                child: Text(
                                  '实际渲染: ${_isActuallyRendering ? "是" : "否"}',
                                  style: TextStyle(
                                    color: _isActuallyRendering
                                        ? Colors.green
                                        : Colors.orange,
                                  ),
                                ),
                              ),

                              // FPS和帧数信息
                              Padding(
                                padding: const EdgeInsets.only(top: 4.0),
                                child: Text(
                                  '解码器FPS: ${_decoderFps.toStringAsFixed(1)}',
                                  style: TextStyle(color: Colors.green),
                                ),
                              ),

                              Padding(
                                padding: const EdgeInsets.only(top: 4.0),
                                child: Text('已渲染帧数: $_renderedFrameCount'),
                              ),

                              // 丢弃帧信息
                              Padding(
                                padding: const EdgeInsets.only(top: 4.0),
                                child: Text(
                                  '已丢弃帧数: $_droppedFramesCount',
                                  style: TextStyle(
                                      color: _droppedFramesCount > 0
                                          ? Colors.orange
                                          : Colors.black),
                                ),
                              ),

                              Padding(
                                padding: const EdgeInsets.only(top: 4.0),
                                child: Text('当前帧索引: $_currentFrameIndex'),
                              ),

                              // 参数集状态
                              Padding(
                                padding: const EdgeInsets.only(top: 4.0),
                                child: Column(
                                  crossAxisAlignment: CrossAxisAlignment.start,
                                  children: [
                                    Text('参数集状态:'),
                                    Padding(
                                      padding: const EdgeInsets.only(
                                          left: 8.0, top: 2.0),
                                      child: Text(
                                          'SPS: ${_hasSentSPS ? "已发送" : "未发送"}'),
                                    ),
                                    Padding(
                                      padding: const EdgeInsets.only(
                                          left: 8.0, top: 2.0),
                                      child: Text(
                                          'PPS: ${_hasSentPPS ? "已发送" : "未发送"}'),
                                    ),
                                    Padding(
                                      padding: const EdgeInsets.only(
                                          left: 8.0, top: 2.0),
                                      child: Text(
                                          'IDR: ${_hasSentIDR ? "已发送" : "未发送"}'),
                                    ),
                                  ],
                                ),
                              ),

                              Padding(
                                padding: const EdgeInsets.only(top: 4.0),
                                child: Text('总帧数: $_totalFrames'),
                              ),

                              // 错误信息
                              if (_error.isNotEmpty)
                                Padding(
                                  padding: const EdgeInsets.only(top: 4.0),
                                  child: Text(
                                    '错误: $_error',
                                    style: TextStyle(
                                        color: Colors.red,
                                        fontWeight: FontWeight.bold),
                                  ),
                                ),

                              // H264文件信息
                              Padding(
                                padding: const EdgeInsets.only(top: 4.0),
                                child: Text('解析的帧数: ${_h264Frames.length}'),
                              ),

                              Padding(
                                padding: const EdgeInsets.only(top: 4.0),
                                child: Text(
                                    'H264文件大小: ${((_h264FileData?.length ?? 0) ~/ 1024)} KB'),
                              ),
                            ],
                          ),
                        ),
                      ),

                      // 控制按钮区
                      Card(
                        child: Padding(
                          padding: const EdgeInsets.all(8.0),
                          child: Wrap(
                            spacing: 8,
                            runSpacing: 8,
                            children: [
                              ElevatedButton(
                                onPressed:
                                    _isInitialized ? null : _initializeDecoder,
                                child: Text('初始化'),
                              ),
                              ElevatedButton(
                                onPressed: (!_isInitialized ||
                                        _isPlaying ||
                                        _h264Frames.isEmpty)
                                    ? null
                                    : _startPlaying,
                                child: Text('播放'),
                              ),
                              ElevatedButton(
                                onPressed: (!_isPlaying) ? null : _stopPlaying,
                                child: Text('停止'),
                              ),
                              ElevatedButton(
                                onPressed: (_textureId == null)
                                    ? null
                                    : _releaseDecoder,
                                child: Text('释放'),
                              ),
                              ElevatedButton(
                                onPressed: () {
                                  setState(() {
                                    // 强制重绘
                                    _renderedFrameCount++;
                                  });
                                },
                                child: Text('刷新'),
                              ),
                            ],
                          ),
                        ),
                      ),

                      // 丢包模拟控制面板
                      Card(
                        child: Padding(
                          padding: const EdgeInsets.all(8.0),
                          child: Column(
                            crossAxisAlignment: CrossAxisAlignment.start,
                            children: [
                              Row(
                                mainAxisAlignment:
                                    MainAxisAlignment.spaceBetween,
                                children: [
                                  Text('丢包模拟',
                                      style: TextStyle(
                                          fontWeight: FontWeight.bold,
                                          fontSize: 16)),
                                  Switch(
                                    value: _enablePacketLoss,
                                    onChanged: (value) {
                                      setState(() {
                                        _enablePacketLoss = value;
                                        if (value) {
                                          _droppedFramesCount = 0; // 重置丢帧计数
                                        }
                                      });
                                    },
                                  ),
                                ],
                              ),

                              // 丢包率控制
                              Row(
                                children: [
                                  Text(
                                      '丢包率: ${(_packetLossRate * 100).toStringAsFixed(0)}%'),
                                  Expanded(
                                    child: Slider(
                                      value: _packetLossRate,
                                      min: 0.0,
                                      max: 1.0,
                                      divisions: 20,
                                      onChanged: _enablePacketLoss
                                          ? (value) {
                                              setState(() {
                                                _packetLossRate = value;
                                              });
                                            }
                                          : null,
                                    ),
                                  ),
                                ],
                              ),

                              // 丢包模式选择
                              Row(
                                children: [
                                  Expanded(
                                    child: CheckboxListTile(
                                      dense: true,
                                      title: Text('爆发式丢包'),
                                      value: _burstPacketLossMode,
                                      onChanged: _enablePacketLoss
                                          ? (value) {
                                              setState(() {
                                                _burstPacketLossMode = value!;
                                              });
                                            }
                                          : null,
                                    ),
                                  ),
                                  Expanded(
                                    child: CheckboxListTile(
                                      dense: true,
                                      title: Text('丢弃I帧'),
                                      value: _dropIFrames,
                                      onChanged: _enablePacketLoss
                                          ? (value) {
                                              setState(() {
                                                _dropIFrames = value!;
                                              });
                                            }
                                          : null,
                                    ),
                                  ),
                                ],
                              ),

                              Row(
                                children: [
                                  Expanded(
                                    child: CheckboxListTile(
                                      dense: true,
                                      title: Text('丢弃P帧'),
                                      value: _dropPFrames,
                                      onChanged: _enablePacketLoss
                                          ? (value) {
                                              setState(() {
                                                _dropPFrames = value!;
                                              });
                                            }
                                          : null,
                                    ),
                                  ),
                                  Expanded(
                                    child: CheckboxListTile(
                                      dense: true,
                                      title: Text('丢弃SPS/PPS'),
                                      value: _dropSPSPPS,
                                      onChanged: _enablePacketLoss
                                          ? (value) {
                                              setState(() {
                                                _dropSPSPPS = value!;
                                              });
                                            }
                                          : null,
                                    ),
                                  ),
                                ],
                              ),

                              // 丢包统计信息
                              Padding(
                                padding: const EdgeInsets.only(top: 8.0),
                                child: Text(
                                  '已丢弃帧数: $_droppedFramesCount',
                                  style: TextStyle(
                                      color: _droppedFramesCount > 0
                                          ? Colors.red
                                          : Colors.black),
                                ),
                              ),
                            ],
                          ),
                        ),
                      ),

                      // 日志区域
                      SizedBox(height: 8),
                      Text('日志:',
                          style: TextStyle(fontWeight: FontWeight.bold)),
                      SizedBox(height: 4),
                      Container(
                        height: 280,
                        decoration: BoxDecoration(
                          color: Colors.black,
                          border: Border.all(color: Colors.grey),
                          borderRadius: BorderRadius.circular(4.0),
                        ),
                        padding: EdgeInsets.all(4),
                        child: ListView.builder(
                          controller: _logScrollController,
                          itemCount: _logs.length,
                          itemBuilder: (context, index) {
                            return Text(
                              _logs[index],
                              style: TextStyle(
                                color: _logs[index].contains('错误')
                                    ? Colors.red
                                    : Colors.green,
                                fontSize: 11,
                                fontFamily: 'monospace',
                              ),
                            );
                          },
                        ),
                      ),
                    ],
                  ),
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }

  // 此方法保留用于手动获取最新统计信息，不再需要定时调用
  Future<void> _updateDecoderStats() async {
    if (_textureId == null || !_isInitialized) return;

    try {
      // 获取所有解码器统计信息
      final stats = await VideoDecodePlugin.getDecoderStats(_textureId!);

      if (mounted) {
        _log("手动更新解码器统计信息: $stats");
      }
    } catch (e) {
      _log("获取解码器统计信息失败: $e");
    }
  }

  Color _getStateColor() {
    switch (_decoderState) {
      case DecoderState.initializing:
        return Colors.orange;
      case DecoderState.ready:
        return Colors.green;
      case DecoderState.rendering:
        return Colors.blue;
      case DecoderState.error:
        return Colors.red;
      case DecoderState.released:
        return Colors.grey;
      default:
        return Colors.black;
    }
  }
}

// 添加错误帧绘制器
class ErrorFramePainter extends CustomPainter {
  @override
  void paint(Canvas canvas, Size size) {
    final random = math.Random();
    final paint = Paint()
      ..color = Colors.red.withOpacity(0.2)
      ..style = PaintingStyle.fill;

    // 绘制随机条纹效果
    for (int i = 0; i < 20; i++) {
      double y = random.nextDouble() * size.height;
      canvas.drawRect(
        Rect.fromLTWH(0, y, size.width, 3 + random.nextDouble() * 5),
        paint,
      );
    }

    // 绘制马赛克块
    for (int i = 0; i < 50; i++) {
      double x = random.nextDouble() * size.width;
      double y = random.nextDouble() * size.height;
      double blockSize = 10 + random.nextDouble() * 30;

      canvas.drawRect(
          Rect.fromLTWH(x, y, blockSize, blockSize),
          Paint()
            ..color = Color.fromRGBO(random.nextInt(255), random.nextInt(255),
                random.nextInt(255), 0.3));
    }
  }

  @override
  bool shouldRepaint(covariant CustomPainter oldDelegate) {
    return true; // 每次都重新绘制以产生动态效果
  }
}