Question

Crashlytics已经表明，在使用CoreAudio框架通过AudioUnit插件更改流音频速度的函数中，发生了很多崩溃。我无法自己复制崩溃，但是它正在影响20％的用户。

在这方面，我不太精通低级C编程或目标C，所以我真的不知道自己在做什么错。也许比我自己更懂C的人可以很容易地指出问题。对于非托管代码，我不太了解内存管理问题。我怀疑这可能是问题所在。我正在使用使用获取新娘头文件技术的Swift代码调用C框架。

这是发生崩溃的功能。我试图设置AudioUnit的参数，该参数是流媒体的AudioGraph的一部分。同样，它在80％的时间内都有效。


var speedNode: AUNode = 0
var speedUnit: AudioUnit?  // could this be the problem?  I call speedUnit before it is initiated?  How I suspect it is initiated be the core audio code since I am not doing it.  Maybe I should check it's not nil before calling it.

func changeRate(rate: Double) {
     self.playbackRate = rate



     CheckError(AudioUnitSetParameter(speedUnit!, kTimePitchParam_Rate, kAudioUnitScope_Global, 0, AudioUnitParameterValue(self.playbackRate), UInt32(Double(MemoryLayout<Double>.size))), "Error")
  }

这是我将AudioGraph连接到媒体流输出的替代功能的代码。

override func attempt(toDeliverAudioFrames audioFrames: UnsafeRawPointer!, ofCount frameCount: Int, streamDescription audioDescription: AudioStreamBasicDescription) -> Int {



    return super.attempt(toDeliverAudioFrames: audioFrames, ofCount: frameCount, streamDescription: audioDescription)
  }

  override func connectOutputBus(_ sourceOutputBusNumber: UInt32, ofNode sourceNode: AUNode, toInputBus destinationInputBusNumber: UInt32, ofNode destinationNode: AUNode, in graph: AUGraph!) throws {

    var speedCd: AudioComponentDescription =
      AudioComponentDescription(componentType: kAudioUnitType_FormatConverter, componentSubType: kAudioUnitSubType_NewTimePitch, componentManufacturer: kAudioUnitManufacturer_Apple, componentFlags: 0, componentFlagsMask: 0)

    CheckError(AUGraphAddNode(graph, &speedCd, &speedNode), "AUGraphAddNode speed failed")


    CheckError(AUGraphNodeInfo(graph,
                               speedNode,
                               nil,
                               &speedUnit), "AUGraphNodeInfo failed")

//    CheckError(AudioUnitSetParameter(speedUnit!, kTimePitchParam_Rate, kAudioUnitScope_Global, 0, AudioUnitParameterValue(self.playbackRate), UInt32(Double(MemoryLayout<Double>.size))), "whatup")

    CheckError(AUGraphConnectNodeInput(graph, sourceNode, sourceOutputBusNumber, speedNode, 0), "connect fail")

    CheckError(AUGraphConnectNodeInput(graph, speedNode, sourceOutputBusNumber, destinationNode, 0), "connect fail")

  }

  override func disposeOfCustomNodes(in graph: AUGraph!) {
    //    if  != nil {
    //      AudioUnitUninitialize(pbUnit!)
    //    }
    //
    //    pbUnit = nil
    //
    //    AUGraphRemoveNode(graph, pbNode)
    //    pbNode = 0
  }

虽然我不太了解代码，但我能够将其一起破解，并且它对80％的用户都有效。代码运行时，允许最终用户移动滑块，从而降低他们正在收听的媒体的速度。

是什么导致与CoreAudio交互的此函数崩溃？

0 个答案: