音频单元并写入到文件 [英] Audio Unit and Writing to file

问题描述

我在OS X上创建实时音频音序器应用程序
实时合成器部分是通过使用AURenderCallback实现。
现在我正在做的功能写渲染的结果WAVE文件（44100Hz 16位立体声）。
格式渲染回调函数是44100Hz支持32位立体声浮动交错。

我使用ExtAudioFileWrite写入文件。
但ExtAudioFileWrite函数返回错误code 1768846202;

我搜索1768846202但我无法获取信息。
你能给我一些提示？

感谢您。

下面是code。

  outFileFormat.mSampleRate = 44100;
    outFileFormat.mFormatID = kAudioFormatLinearPCM;
    outFileFormat.mFormatFlags =
 kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked;
    outFileFormat.mBitsPerChannel = 16;
    outFileFormat.mChannelsPerFrame = 2;
    outFileFormat.mFramesPerPacket = 1;
    outFileFormat.mBytesPerFrame =
 outFileFormat.mBitsPerChannel / 8 * outFileFormat.mChannelsPerFrame;
    outFileFormat.mBytesPerPacket =
 outFileFormat.mBytesPerFrame * outFileFormat.mFramesPerPacket; AudioBufferList * ioList;
    ioList =（AudioBufferList *）释放calloc（1，sizeof的（AudioBufferList）
         + 2 * sizeof的（AudioBuffer））;
    ioList-＆GT; mNumberBuffers = 2;
    ioList-＆GT; mBuffers [0] .mNumberChannels = 1;
    ioList-＆GT; mBuffers [0] .mDataByteSize = allocByteSize / 2;
    ioList-＆GT; mBuffers [0] .mData = ioDataL;
 ioList-＆GT; mBuffers [1] .mNumberChannels = 1;
    ioList-＆GT; mBuffers [1] .mDataByteSize = allocByteSize / 2;
    ioList-＆GT; mBuffers [1] .mData = ioDataR;...而（1）{
  //使用呈现回调FUNC填充缓冲区。
  RenderCallback（个体经营，零，零，0，框架，ioList）;        //我想创建一个秒的文件。
        如果（renderedFrames＆GT; = 44100）打破;  ERR = ExtAudioFileWrite（outAudioFileRef，框架，ioList）;
  如果（ERR！=诺尔）{
   的NSLog（@出错写入文件）;
   转到errorExit;
  }
    }
 

解决方案

一些错误codeS实际上是四个字符的字符串。核心音频本书提供了一个很好的功能来处理错误。

静态无效CheckError（OSStatus错误，为const char *操作）
{
    如果（错误==诺尔）回报;

 字符海峡[20];
//看看它似乎是一个4煤焦code
*（UInt32的*）（STR + 1）= CFSwapInt32HostToBig（误差）;
如果（isprint判断（STR [1]）及＆放大器; isprint判断（STR [2]）及＆放大器; isprint判断（STR [3]）及＆放大器; isprint判断（STR [4]））{
    海峡[0] = STR [5] ='\\'';
    海峡[6] ='\\ 0';
}其他
    //没有，将其格式化为整数
    sprintf的（STR，％D，（int）的误差）;fprintf中（标准错误，错误：％s（％S）\\ n，操作，STR）;出口（1）;
 

}

使用这样的：

  CheckError（ExtAudioFileSetProperty（OUTPUTFILE，
                                 kExtAudioFileProperty_ codecManufacturer，
                                 的sizeof（codeC）
                                 ＆安培; codeC），设置codeC。）;
 

I'm creating real-time audio sequencer app on OS X. Real-time synth part is implemented by using AURenderCallback. Now I'm making function to write rendered result to Wave File (44100Hz 16bit Stereo). Format for render-callback function is 44100Hz 32bit float Stereo interleaved.

I'm using ExtAudioFileWrite to write to file. But ExtAudioFileWrite function returns error code 1768846202;

I searched 1768846202 but I couldn't get information. Would you give me some hints?

Thank you.

Here is code.

    outFileFormat.mSampleRate = 44100;
    outFileFormat.mFormatID = kAudioFormatLinearPCM;
    outFileFormat.mFormatFlags = 
 kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked;
    outFileFormat.mBitsPerChannel = 16;
    outFileFormat.mChannelsPerFrame = 2;
    outFileFormat.mFramesPerPacket = 1;
    outFileFormat.mBytesPerFrame = 
 outFileFormat.mBitsPerChannel / 8 * outFileFormat.mChannelsPerFrame;
    outFileFormat.mBytesPerPacket = 
 outFileFormat.mBytesPerFrame * outFileFormat.mFramesPerPacket;

 AudioBufferList *ioList;
    ioList = (AudioBufferList*)calloc(1, sizeof(AudioBufferList)
         + 2 * sizeof(AudioBuffer));
    ioList->mNumberBuffers = 2;
    ioList->mBuffers[0].mNumberChannels = 1;
    ioList->mBuffers[0].mDataByteSize = allocByteSize / 2;
    ioList->mBuffers[0].mData = ioDataL;
 ioList->mBuffers[1].mNumberChannels = 1;
    ioList->mBuffers[1].mDataByteSize = allocByteSize / 2;
    ioList->mBuffers[1].mData = ioDataR;

...

while (1) {
  //Fill buffer by using render callback func.
  RenderCallback(self, nil, nil, 0, frames, ioList);

        //i want to create one sec file.
        if (renderedFrames >= 44100) break;

  err = ExtAudioFileWrite(outAudioFileRef, frames , ioList);
  if (err != noErr){
   NSLog(@"ERROR AT WRITING TO FILE");
   goto errorExit;
  }
    }

解决方案

Some of the error codes are actually four character strings. The Core Audio book provides a nice function to handle errors.

static void CheckError(OSStatus error, const char *operation) { if (error == noErr) return;

char str[20];
// see if it appears to be a 4-char-code
*(UInt32 *)(str + 1) = CFSwapInt32HostToBig(error);
if (isprint(str[1]) && isprint(str[2]) && isprint(str[3]) && isprint(str[4])) {
    str[0] = str[5] = '\'';
    str[6] = '\0';
} else
    // no, format it as an integer
    sprintf(str, "%d", (int)error);

fprintf(stderr, "Error: %s (%s)\n", operation, str);

exit(1);

}

Use it like this:

CheckError(ExtAudioFileSetProperty(outputFile, 
                                 kExtAudioFileProperty_CodecManufacturer, 
                                 sizeof(codec), 
                                 &codec), "Setting codec.");

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