从麦克风播放的音频断断续续，听起来像空气吹进麦克风答案

【问题标题】：Audio being played from microphone is choppy and sounds like air blowing into the microphone从麦克风播放的音频断断续续，听起来像空气吹进麦克风
【发布时间】：2017-03-09 17:02:51
【问题描述】：

我正在使用以下方法录制音频：

    localInput?.installTap(onBus: 0, bufferSize: 4096, format: localInputFormat) {
        (buffer, time) -> Void in

        let audioBuffer = self.audioBufferToBytes(audioBuffer: buffer)
        let output = self.outputStream!.write(audioBuffer, maxLength: Int(buffer.frameLength))

        if output > 0 {
            print("\(#file) > \(#function) > \(output) bytes written from queue \(self.currentQueueName())")
        }
        else if output == -1 {
            let error = self.outputStream!.streamError
            print("\(#file) > \(#function) > Error writing to stream: \(error?.localizedDescription)")
        }
    }

我的 localInputFormat 如下：

self.localInput = self.localAudioEngine.inputNode
self.localAudioEngine.attach(self.localAudioPlayer)
self.localInputFormat = self.localInput?.inputFormat(forBus: 0)
self.localAudioEngine.connect(self.localAudioPlayer, to: self.localAudioEngine.mainMixerNode, format: self.localInputFormat)

audioBufferToBytes函数如下：

func audioBufferToBytes(audioBuffer: AVAudioPCMBuffer) -> [UInt8] {
    let srcLeft = audioBuffer.floatChannelData![0]
    let bytesPerFrame = audioBuffer.format.streamDescription.pointee.mBytesPerFrame
    let numBytes = Int(bytesPerFrame * audioBuffer.frameLength)

    // initialize bytes by 0 
    var audioByteArray = [UInt8](repeating: 0, count: numBytes)

    srcLeft.withMemoryRebound(to: UInt8.self, capacity: numBytes) { srcByteData in
        audioByteArray.withUnsafeMutableBufferPointer {
            $0.baseAddress!.initialize(from: srcByteData, count: numBytes)
        }
    }

    return audioByteArray
}

在另一台设备上，当我收到数据时，我必须将其转换回来。因此，在收到它时，它会通过以下方式运行：

func bytesToAudioBuffer(_ buf: [UInt8]) -> AVAudioPCMBuffer {

    let fmt = AVAudioFormat(commonFormat: .pcmFormatFloat32, sampleRate: 44100, channels: 1, interleaved: true)
    let frameLength = UInt32(buf.count) / fmt.streamDescription.pointee.mBytesPerFrame

    let audioBuffer = AVAudioPCMBuffer(pcmFormat: fmt, frameCapacity: frameLength)
    audioBuffer.frameLength = frameLength

    let dstLeft = audioBuffer.floatChannelData![0]

    buf.withUnsafeBufferPointer {
        let src = UnsafeRawPointer($0.baseAddress!).bindMemory(to: Float.self, capacity: Int(frameLength))
        dstLeft.initialize(from: src, count: Int(frameLength))
    }

    return audioBuffer
}

最后，我们播放这个音频数据：

                self.audioPlayerQueue.async {
                    self.peerAudioPlayer.scheduleBuffer(audioBuffer)

                    if (!self.peerAudioPlayer.isPlaying && self.localAudioEngine.isRunning) {
                        self.peerAudioPlayer.play()
                    }
                }

但是，在任一扬声器上，我只听到有人每隔半秒（ish）敲击麦克风的声音。不是他们真的在说话什么的。我想这是由于我从音频缓冲区转换为字节并返回，但我不确定。有没有人发现上面有任何问题？

谢谢。

【问题讨论】：

标签： ios swift audio type-conversion avaudioplayer

【解决方案1】：

如果有人对解决方案感兴趣，基本上问题是录制设备上的音频是 17640 字节，但要流式传输它，它会将其分成更小的部分，并且在接收设备上我必须读取第一个 17640字节，然后播放音频。不播放收到的每一小段数据。

【讨论】：