音频队列：AudioQueueStart返回-50 [英] Audio Queue : AudioQueueStart returns -50

问题描述

我正在尝试在GLES应用程序（Unity3d）中编写麦克风功率计模块。
它在UIKit应用程序中工作正常。但是当我整合到我的unity3d项目中时，AudioQueue无法启动属性。调用AudioQueueStart的结果代码总是-50，但-50是什么意思？我在iOS Developer Library中找不到引用。

I'm trying to write a microphone power meter module in a GLES app (Unity3d). It works fine in UIKit application. But when I integrate into my unity3d project, the AudioQueue cannot start property.The result code of calling AudioQueueStart is always -50, but what does -50 mean? I can't find a reference in iOS Developer Library.

我已经搜索过这个问题，并且知道有人在cocos2d应用程序中遇到同样的问题。也许这有一定的相关性。

I have searched about this problem and know someone has the same problem in a cocos2d application. Maybe this has some relevance.

这是我的开始音频队列的代码：

Here is my code for Start Audio Queue:

UInt32 ioDataSize = sizeof(sampleRate);
AudioSessionGetProperty(kAudioSessionProperty_CurrentHardwareSampleRate, &ioDataSize, &sampleRate); //returns noErr
format.mSampleRate = sampleRate;
format.mFormatID = kAudioFormatLinearPCM;
format.mFormatFlags = kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked;
format.mFramesPerPacket = format.mChannelsPerFrame = 1;
format.mBitsPerChannel = 16;
format.mBytesPerPacket = format.mBytesPerFrame = 2;

AudioQueueNewInput(&format, listeningCallback, self, NULL, NULL, 0, &queue); //returns noErr

AudioQueueBufferRef buffers[3];
for (NSInteger i = 0; i < 3; ++i) { 
    AudioQueueAllocateBuffer(queue, 735, &buffers[i]); //returns noErr
    AudioQueueEnqueueBuffer(queue, buffers[i], 0, NULL); //returns noErr
}

levels = (AudioQueueLevelMeterState *)calloc(sizeof(AudioQueueLevelMeterState), format.mChannelsPerFrame);
UInt32 trueValue = true;
AudioQueueSetProperty(queue, kAudioQueueProperty_EnableLevelMetering, &trueValue, sizeof(UInt32)); //returns noErr

AudioQueueStart(queue, NULL); //returns -50

推荐答案

以下适用于我：

添加：

AVAudioSession * session = [AVAudioSession sharedInstance];

    if (!session) printf("ERROR INITIALIZING AUDIO SESSION! \n");
    else{


        [session setCategory:AVAudioSessionCategoryPlayAndRecord error:&nsError];

        if (nsError) printf("couldn't set audio category!");



        [session setActive:YES error:&nsError];
        if (nsError) printf("AudioSession setActive = YES failed");
    }

在 AudioQueueStart（myQueue，NULL）之前;

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