4 changed files with 454 additions and 305 deletions
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import AVFoundation |
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class MicrophoneCapture: NSObject { |
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// MARK: - 单例实例 |
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/** |
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* 单例实例，确保整个应用中只有一个音频捕获对象 |
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* 避免多个实例同时访问麦克风资源导致冲突 |
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*/ |
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static let shared = MicrophoneCapture() |
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|
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private var audioEngine: AVAudioEngine! |
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private var audioSession: AVAudioSession! |
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private var audioFormat: AVAudioFormat? |
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private var audioInputNode: AVAudioInputNode! |
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private var sampleRate: Double = 16000 // 修改为16000采样率，符合Microsoft要求 |
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private var isCapturing = false |
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|
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// 音频数据回调 |
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var audioDataHandler: ((Data) -> Void)? |
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/** |
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* 私有初始化方法，防止外部直接创建实例 |
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* 只能通过shared单例访问 |
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*/ |
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private override init() { |
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super.init() |
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setupAudioSession() |
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} |
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|
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/// 获取最佳音频格式 (iOS 通常支持标准采样率) |
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public func getOptimalAudioFormat() -> AVAudioFormat? { |
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let sampleRate: Double = 16000 // Microsoft要求最低16kHz |
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return AVAudioFormat( |
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commonFormat: .pcmFormatInt16, // 16位little endian有符号整数 |
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sampleRate: sampleRate, |
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channels: 1, |
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interleaved: true |
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) |
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} |
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|
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// MARK: - 音频会话配置 |
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/** |
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* 配置音频会话参数 |
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* 设置音频类别、采样率、缓冲区大小等 |
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*/ |
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public func setupAudioSession() { |
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audioFormat = getOptimalAudioFormat() |
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audioSession = AVAudioSession.sharedInstance() |
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do { |
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// 设置音频会话参数 |
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try audioSession.setCategory(.playAndRecord, |
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mode: .videoChat, |
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options: [//.allowBluetooth, |
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// .allowAirPlay, |
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.allowBluetoothA2DP, |
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.mixWithOthers, |
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.defaultToSpeaker |
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]) |
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try audioSession.setPreferredSampleRate(sampleRate) |
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try audioSession.setPreferredIOBufferDuration(0.005) // 5ms缓冲 |
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// 设置蓝牙设备优先级 |
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if let bluetoothInput = audioSession.availableInputs?.first(where: { $0.portType == .bluetoothHFP }) { |
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try audioSession.setPreferredInput(bluetoothInput) |
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} |
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|
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try audioSession.setActive(true) |
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print("音频会话配置成功") |
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} catch { |
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print("音频会话配置失败: \(error.localizedDescription)") |
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} |
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} |
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|
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// MARK: - 开始捕获 |
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/** |
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* 开始音频捕获 |
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* 检查麦克风权限并启动音频引擎 |
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*/ |
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public func startCapture() throws { |
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guard !isCapturing else { return } |
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print("开始捕获") |
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// 检查麦克风权限 |
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switch audioSession.recordPermission { |
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case .granted: |
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try setupAudioEngine() |
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case .denied: |
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throw NSError(domain: "麦克风权限被拒绝", code: 0) |
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case .undetermined: |
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audioSession.requestRecordPermission { granted in |
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if granted { |
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do { |
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try self.setupAudioEngine() |
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} catch { |
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print("音频引擎设置失败: \(error.localizedDescription)") |
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} |
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} |
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} |
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@unknown default: |
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throw NSError(domain: "未知权限状态", code: 1) |
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} |
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} |
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/** |
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* 检查音频格式是否符合Microsoft音频堆栈要求 |
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* 如果符合则无需转换，直接使用原始格式 |
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*/ |
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private func isMicrosoftCompatibleFormat(_ format: AVAudioFormat) -> Bool { |
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// Microsoft支持的采样率：16kHz的整数倍，最低16kHz |
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let sampleRate = format.sampleRate |
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guard sampleRate >= 16000 && sampleRate.truncatingRemainder(dividingBy: 16000) == 0 else { |
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return false |
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} |
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// Microsoft支持的格式 |
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switch format.commonFormat { |
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case .pcmFormatFloat32: // 32位IEEE little endian浮点 |
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return true |
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case .pcmFormatInt32: // 32位little endian有符号整数 |
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return true |
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case .pcmFormatInt16: // 16位little endian有符号整数 |
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return true |
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default: |
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return false |
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} |
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} |
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|
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/** |
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* 设置音频引擎和音频处理管道 |
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* 根据Microsoft音频堆栈要求优化格式转换 |
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*/ |
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private func setupAudioEngine() throws { |
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audioEngine = AVAudioEngine() |
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audioInputNode = audioEngine.inputNode |
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// 获取实际硬件采样率 |
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sampleRate = audioSession.sampleRate |
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// 移除之前的音频处理块，避免重复添加 |
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audioInputNode.removeTap(onBus: 0) |
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// 设置音频格式 |
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let inputFormat = audioInputNode.inputFormat(forBus: 0) |
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// iOS 13+ 启用语音处理 |
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if #available(iOS 13.0, *) { |
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try audioInputNode.setVoiceProcessingEnabled(true) |
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} |
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// 检查输入格式是否符合Microsoft要求 |
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let needsConversion = !isMicrosoftCompatibleFormat(inputFormat) |
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// if needsConversion { |
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// 需要格式转换 |
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guard let targetFormat = audioFormat, |
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let converter = AVAudioConverter(from: inputFormat, to: targetFormat) else { |
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throw NSError(domain: "AudioSetup", code: 2) |
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} |
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print("输入格式不符合Microsoft要求，进行格式转换") |
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print("输入格式: \(inputFormat.sampleRate)Hz, \(inputFormat.commonFormat.rawValue)") |
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print("目标格式: \(targetFormat.sampleRate)Hz, \(targetFormat.commonFormat.rawValue)") |
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// 添加tap进行格式转换 |
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audioInputNode.installTap(onBus: 0, |
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bufferSize: 1024, |
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format: inputFormat) { [weak self] buffer, when in |
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guard let strongSelf = self else { return } |
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// 创建目标格式的音频缓冲区 |
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let convertedBuffer = AVAudioPCMBuffer( |
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pcmFormat: targetFormat, |
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frameCapacity: AVAudioFrameCount( |
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targetFormat.sampleRate * Double(buffer.frameLength) / buffer.format.sampleRate |
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) |
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)! |
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var error: NSError? |
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// 执行音频格式转换 |
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let status = converter.convert( |
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to: convertedBuffer, |
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error: &error, |
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withInputFrom: { inNumPackets, outStatus in |
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outStatus.pointee = .haveData |
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return buffer |
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} |
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) |
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// 转换成功且无错误 |
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if status == .haveData, error == nil { |
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let data = strongSelf.audioBufferToData(convertedBuffer) |
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print("转换后数据长度: \(data.count)") |
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strongSelf.audioDataHandler?(data) |
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} |
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} |
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// } else { |
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// // 格式已符合Microsoft要求，直接使用 |
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// print("输入格式符合Microsoft要求，无需转换") |
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// print("格式: \(inputFormat.sampleRate)Hz, \(inputFormat.commonFormat.rawValue)") |
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// audioInputNode.installTap(onBus: 0, |
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// bufferSize: 1024, |
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// format: inputFormat) { [weak self] buffer, when in |
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// guard let strongSelf = self else { return } |
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//strongSelf.processAudioBuffer(buffer) |
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// // 直接处理原始音频数据 |
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// let data = strongSelf.audioBufferToData(convertedBuffer) |
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// print("转换后数据长度: \(data.count)") |
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// strongSelf.audioDataHandler?(data) |
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// } |
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// } |
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// 启动引擎 |
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do { |
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try audioEngine.start() |
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isCapturing = true |
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} catch { |
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print("音频引擎启动失败: \(error.localizedDescription)") |
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} |
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} |
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/** |
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* 将音频缓冲区转换为Data格式 |
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* 支持16位整数和32位浮点格式 |
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*/ |
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private func audioBufferToData(_ buffer: AVAudioPCMBuffer) -> Data { |
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let frameLength = Int(buffer.frameLength) |
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let channelCount = 1 |
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let dataLength = frameLength * channelCount * MemoryLayout<Int16>.size |
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// Handle 16-bit integer format |
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if let int16Data = buffer.int16ChannelData { |
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return Data( |
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bytes: int16Data.pointee, |
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count: dataLength |
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) |
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} |
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// Handle float format |
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else if let floatData = buffer.floatChannelData { |
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var int16Array = [Int16](repeating: 0, count: frameLength) |
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let floatBuffer = floatData.pointee |
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for i in 0..<frameLength { |
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let sample = floatBuffer[i] |
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let clamped = max(-1.0, min(sample, 1.0)) |
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let scaled = clamped * Float(Int16.max) |
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int16Array[i] = Int16(scaled) |
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} |
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return Data( |
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bytes: int16Array, |
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count: dataLength |
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) |
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} |
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return Data() // Fallback for unsupported formats |
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} |
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// MARK: - 音频数据处理 |
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/** |
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* 处理音频缓冲区数据 |
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* 将浮点音频数据转换为16位PCM格式 |
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*/ |
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private func processAudioBuffer(_ buffer: AVAudioPCMBuffer) { |
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guard let floatData = buffer.floatChannelData?[0] else { return } |
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let channelCount = Int(buffer.format.channelCount) |
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let frameLength = Int(buffer.frameLength) |
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let sampleCount = frameLength * channelCount |
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// 转换为16位PCM数据（兼容大多数音频处理场景） |
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var pcmData = Data() |
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for i in 0..<sampleCount { |
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let sample = floatData[i] * Float32(Int16.max) |
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var pcmSample = Int16(sample) |
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pcmData.append(Data(bytes: &pcmSample, count: MemoryLayout<Int16>.size)) |
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} |
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// 通过回调返回数据 |
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DispatchQueue.main.async { |
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print("音频数据回调\(pcmData.count)") |
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self.audioDataHandler?(pcmData) |
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} |
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} |
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// MARK: - 停止捕获 |
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/** |
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* 停止音频捕获 |
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* 清理音频引擎和会话资源 |
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*/ |
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func stopCapture() { |
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guard isCapturing else { return } |
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audioEngine.stop() |
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audioInputNode.removeTap(onBus: 0) |
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// try? audioSession.setActive(false) |
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isCapturing = false |
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} |
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/** |
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* 重置音频捕获状态 |
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* 用于单例模式下的状态清理 |
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*/ |
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func reset() { |
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stopCapture() |
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audioDataHandler = nil |
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} |
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deinit { |
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stopCapture() |
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} |
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} |
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