来自 AudioUnitRender swift 的 paramErr -50答案

【问题标题】：paramErr -50 from AudioUnitRender swift来自 AudioUnitRender swift 的 paramErr -50
【发布时间】：2016-10-06 03:01:23
【问题描述】：

我正在尝试使用 AudioUnit Render 进行离线渲染，但我看不出哪个参数有误。也许是缓冲的大小。

我正在使用 swift 和核心音频来解决这个问题，这是我从 GenericOutput 音频单元中提取的一些代码。

谢谢

   func pullGenericOutput(_ player: UnsafeMutablePointer<AUGraphPlayer>){
        //var player = AUGraphPlayer()

    do {
    var flags = AudioUnitRenderActionFlags()
    var inTimeStamp = AudioTimeStamp()
    inTimeStamp.mFlags = .sampleTimeValid

    var busNumber:UInt32 = 0
    var numberFrames:UInt32 = 512
    inTimeStamp.mSampleTime = 0
    var channelCount = 2

    print("Final numberFrames :\(numberFrames)")
    var totFrms = MaxSampleTime

    while totFrms > 0 {

        if totFrms < numberFrames {
            numberFrames = totFrms
            print("Final numberFrames :\(numberFrames)")
            print("stuck")
            }
        else {
            totFrms -= numberFrames
        }
        var bufferList = AudioBufferList()
    bufferList.mNumberBuffers = UInt32(channelCount)

    for j in 0..<channelCount {
        var buffer = AudioBuffer()
    buffer.mNumberChannels = 1
    buffer.mDataByteSize = numberFrames * UInt32(MemoryLayout.size(ofValue: UInt32.self))
    buffer.mData = calloc(Int(numberFrames), MemoryLayout.size(ofValue: UInt32.self))

    bufferList.mBuffers = buffer
    }//for loop end
        //var actionFlags = AudioUnitRenderActionFlags(rawValue: UInt32(flags))
       // print(actionFlags)
    Utility.check(AudioUnitRender(player.pointee.mGIO!, &flags, &inTimeStamp, busNumber, numberFrames, &bufferList), operation: "AudioUnitRender mGIO")

        inTimeStamp.mSampleTime += inTimeStamp.mSampleTime

    Utility.check(ExtAudioFileWrite( player.pointee.extAudioFile!, numberFrames, &bufferList), operation: ("extaudiofilewrite fail"))
    }//while loop end
    self.filesSavingCompleted(player)
    }
    }

【问题讨论】：

音频 -50 错误通常涉及设置不受支持的音频格式。您的格式规范是什么（位、字节、通道、采样率等）？
我正在使用这个 imgur.com/a/E9N72 我使用 getproperty 来填充其余部分

标签： ios swift audio core-audio

【解决方案1】：

试试这个！

var flags: AudioUnitRenderActionFlags = AudioUnitRenderActionFlags(rawValue: 0)
var inTimeStamp = AudioTimeStamp()

memset(&inTimeStamp, 0, MemoryLayout.size(ofValue: inTimeStamp))
inTimeStamp.mFlags = .smpteTimeValid

let busNumber: UInt32 = 0
var numberFrames: UInt32 = 1024
inTimeStamp.mSampleTime = 0
let channelCount: Int = 2
var totFrms: Int = Int(maxSampleTime)

while totFrms > 0 {

    if UInt32(totFrms) < numberFrames {
        numberFrames = UInt32(totFrms)
    } else {
        totFrms -= Int(numberFrames)
    }

    let bufferList = AudioBufferList.allocate(maximumBuffers: Int(channelCount))

    for i in 0...channelCount-1 {

        var buffer = AudioBuffer()
        buffer.mNumberChannels = 1
        buffer.mDataByteSize = numberFrames * 4
        buffer.mData = calloc(Int(numberFrames), 4)
        bufferList[i] = buffer

        var result: OSStatus = AudioUnitRender(mGIO!, &flags, &inTimeStamp, busNumber, numberFrames, bufferList.unsafeMutablePointer)
                print(result)            
        if result == 0 {
          result = ExtAudioFileWrite(extAudioFile!, numberFrames, bufferList.unsafeMutablePointer)
        }
        inTimeStamp.mSampleTime += Float64(numberFrames)
    }
}

【讨论】：