Core Audio（iOS 5.1）Reverb2属性不存在，错误代码-10877 [英] Core Audio (iOS 5.1) Reverb2 properties do not exist, error code -10877

问题描述

我正在玩Apple的示例项目LoadPresetDemo。我已将混响音频单元 AudioUnit kAudioUnitSubType_Reverb2 添加到图表中，这是唯一可用的iOS混响。在CoreAudio头文件AudioUnitParameters.h中，它声明Reverb2应该响应这些参数：

I am playing with Apple's sample project "LoadPresetDemo". I have added the reverb audio unit AudioUnit kAudioUnitSubType_Reverb2 to the graph, which is the only iOS reverb available. In the CoreAudio header file "AudioUnitParameters.h", it states that Reverb2 should respond to these parameters:

enum {
    // Global, CrossFade, 0->100, 100
    kReverb2Param_DryWetMix = 0,
    // Global, Decibels, -20->20, 0
    kReverb2Param_Gain = 1,
    // Global, Secs, 0.0001->1.0, 0.008
    kReverb2Param_MinDelayTime = 2,
    // Global, Secs, 0.0001->1.0, 0.050
    kReverb2Param_MaxDelayTime = 3,
    // Global, Secs, 0.001->20.0, 1.0
    kReverb2Param_DecayTimeAt0Hz = 4,
    // Global, Secs, 0.001->20.0, 0.5
    kReverb2Param_DecayTimeAtNyquist = 5,
    // Global, Integer, 1->1000
    kReverb2Param_RandomizeReflections = 6,
};

AUGraph初始化并启动后，所有内容都会编译，我听到声音。

After the AUGraph has been initialized and started, everything compiles, I hear sound.

接下来，我改变了kReverb2Param_DryWetMix参数（改为完全湿混合）：

Next, I alter the kReverb2Param_DryWetMix parameter (changing to full wet mix):

AudioUnitSetParameter(_reverbUnit, kAudioUnitScope_Global, 0, kReverb2Param_DryWetMix, 100.0f, 0);

一切都很好，我听到完全湿混合混响的声音。

All good, I hear sound with full wet mixed reverb.

现在听到的是我遇到问题的地方。当尝试更改 kReverb2Param_DryWetMix 以外的任何参数时，我收到错误代码 -10877 。似乎头文件中列出的这些其他参数实际上并不存在。

Now hear is where I run into issues. When trying to alter any parameter other than kReverb2Param_DryWetMix I get error code -10877. It seems as if these other parameters listed in the header file do not actually exist.

例如，调用

AudioUnitSetParameter(_reverbUnit, kAudioUnitScope_Global, 0, kReverb2Param_DecayTimeAtNyquist, 20.0f, 0)

抛出 -10877 错误。

这是一个错误吗？我是否省略了任何音频框架？我没有导入特定的音频标题吗？

Is this a bug? Have I omitted any audio frameworks? Have I not imported specific audio headers?

包括的当前音频框架是AVFoundation和AudioToolbox。
当前的音频输入是

The current audio frameworks included are AVFoundation and AudioToolbox. The current audio imports are

#import <AudioToolbox/AudioToolbox.h>
#import <AVFoundation/AVFoundation.h>
#import <CoreAudio/CoreAudioTypes.h>

我已经搜索谷歌没有解决方案。我知道当Google路由失败时我遇到了问题。任何帮助将不胜感激。

I have scoured google with no solution. I know I have problems when the Google route fails. Any help would be greatly appreciated.

注意：我使用模拟器和iPhone 4S设备进行了测试，同样的问题。

Note: I tested with simulator and iPhone 4S device, same problem.

更新：我试过了

AudioUnitGetParameter(_reverbUnit, kReverb2Param_DecayTimeAtNyquist, kAudioUnitScope_Global, 0, &value)

并返回值 0.500000 ，这意味着该财产确实存在。那么我在设置值时做错了什么？

and it returns a value of 0.500000, which means the property does exist. So what am I doing wrong in setting the value?

推荐答案

Doh！我意识到我在 AudioUnitSetParameter 与 AudioUnitSetProperty 混淆，包括他们的参数。男人，微妙但邪恶。

Doh! I realize that I was confusing AudioUnitSetParameter with AudioUnitSetProperty, including their parameters. Man, subtle but evil.

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