Swift 将AVAudioPCMBuffer转换为NSData并返回

如何将

AVAudioPCMBuffer

转换为

NSData

？如果它应该按照

let data = NSData(bytes: buffer.floatChannelData, length: bufferLength)

那么如何计算缓冲区长度呢

---

如何将

NSData

转换为

AVAudioPCMBuffer

？

缓冲区长度是frameCapacity*bytesPerFrame。以下是可以在NSData和AVAudioPCMBuffer之间进行转换的函数

func toNSData(PCMBuffer: AVAudioPCMBuffer) -> NSData {
    let channelCount = 1  // given PCMBuffer channel count is 1
    var channels = UnsafeBufferPointer(start: PCMBuffer.floatChannelData, count: channelCount)
    var ch0Data = NSData(bytes: channels[0], length:Int(PCMBuffer.frameCapacity * PCMBuffer.format.streamDescription.memory.mBytesPerFrame))
    return ch0Data
}       

func toPCMBuffer(data: NSData) -> AVAudioPCMBuffer {
    let audioFormat = AVAudioFormat(commonFormat: AVAudioCommonFormat.PCMFormatFloat32, sampleRate: 8000, channels: 1, interleaved: false)  // given NSData audio format
    var PCMBuffer = AVAudioPCMBuffer(PCMFormat: audioFormat, frameCapacity: UInt32(data.length) / audioFormat.streamDescription.memory.mBytesPerFrame)
    PCMBuffer.frameLength = PCMBuffer.frameCapacity
    let channels = UnsafeBufferPointer(start: PCMBuffer.floatChannelData, count: Int(PCMBuffer.format.channelCount))
    data.getBytes(UnsafeMutablePointer<Void>(channels[0]) , length: data.length)
    return PCMBuffer
}

func toNSData（PCMBuffer:AVAudioPCMBuffer）->NSData{
设channelCount=1//给定的PCMBuffer通道计数为1
var channels=UnsafeBufferPointer（开始：PCMBuffer.floatChannelData，计数：channelCount）
var ch0Data=NSData（字节：通道[0]，长度：Int（PCMBuffer.frameCapacity*PCMBuffer.format.streamDescription.memory.mBytesPerFrame））
返回ch0Data
}       
func toPCMBuffer（数据：NSData）->AVAudioPCMBuffer{
let audioFormat=AVAudioFormat（commonFormat:AVAudioCommonFormat.PCMFormatFloat32，采样器：8000，通道：1，交错：false）//给定的NSData音频格式
var PCMBuffer=AVAudioPCMBuffer（PCMFormat:audioFormat，frameCapacity:UInt32（data.length）/audioFormat.streamDescription.memory.mBytesPerFrame）
PCMBuffer.frameLength=PCMBuffer.frameCapacity
let channels=UnsafeBufferPointer（开始：PCMBuffer.floatChannelData，计数：Int（PCMBuffer.format.channelCount））
data.getBytes（unsafemeutablepointer（通道[0]），长度：data.length）
回程传送器
}

如果您通过audioBufferList API进行复制，那么复制缓冲区会容易得多。无论实际缓冲区的格式是什么，这也可以工作

extension Data {
    init(buffer: AVAudioPCMBuffer, time: AVAudioTime) {
        let audioBuffer = buffer.audioBufferList.pointee.mBuffers
        self.init(bytes: audioBuffer.mData!, count: Int(audioBuffer.mDataByteSize))
    }

    func makePCMBuffer(format: AVAudioFormat) -> AVAudioPCMBuffer? {
        let streamDesc = format.streamDescription.pointee
        let frameCapacity = UInt32(count) / streamDesc.mBytesPerFrame
        guard let buffer = AVAudioPCMBuffer(pcmFormat: format, frameCapacity: frameCapacity) else { return nil }

        buffer.frameLength = buffer.frameCapacity
        let audioBuffer = buffer.audioBufferList.pointee.mBuffers

        withUnsafeBytes { (bufferPointer) in
            guard let addr = bufferPointer.baseAddress else { return }
            audioBuffer.mData?.copyMemory(from: addr, byteCount: Int(audioBuffer.mDataByteSize))
        }

        return buffer
    }
}

---

我也是@Massimo。我成功地在

AvaudiOpcBuffer

中转换了

NSData

（我不需要反转，所以没有代码）：@Massimo如何反转它，意味着AvaudiOpcBuffer转换为16位NSData？目标-c答案？对于Swift 4，将

streamDescription.memory

替换为

streamDescription.pointee

。为避免

“withUnsafeBytes”被弃用，请使用“withUnsafeBytes”（uu:（UnsafeRawBufferPointer）throws->R）rethrrows->R'

使用Swift 5发出警告，您可以将

addr.baseAddress

传递到

copyMemory

函数，而不是

addr

。