AudioFileWriteBytes失敗，錯誤代碼-40

我想寫使用AudioFileWriteBytes（）原始音頻字節的文件。下面是我在做什麼：AudioFileWriteBytes失敗，錯誤代碼-40

void writeSingleChannelRingBufferDataToFileAsSInt16(AudioFileID audioFileID, AudioConverterRef audioConverter, ringBuffer *rb, SInt16 *holdingBuffer) { 
// First, figure out which bits of audio we'll be 
// writing to file from the ring buffer 

    UInt32 lastFreshSample = rb->lastWrittenIndex; 
    OSStatus status; 
    int numSamplesToWrite; 
    UInt32 numBytesToWrite; 


    if (lastFreshSample < rb->lastReadIndex) { 
     numSamplesToWrite = kNumPointsInWave + lastFreshSample - rb->lastReadIndex - 1; 
    } 
    else { 
     numSamplesToWrite = lastFreshSample - rb->lastReadIndex; 
    } 
    numBytesToWrite = numSamplesToWrite*sizeof(SInt16);

然後我們的音頻數據（存儲爲花車）複製到將直接寫入文件保持緩衝（SInt16）。複製看起來很時髦，因爲它來自環形緩衝區。

UInt32 buffLen = rb->sizeOfBuffer - 1; 
    for (int i=0; i < numSamplesToWrite; ++i) { 
     holdingBuffer[i] = rb->data[(i + rb->lastReadIndex) & buffLen]; 
    }

好的，現在我們嘗試從SInt16緩衝區「holdingBuffer」寫入音頻到音頻文件。該的NSLog會吐出一個錯誤-40，但還聲稱，它的寫入字節。沒有數據寫入文件。

status = AudioFileWriteBytes(audioFileID, NO, 0, &numBytesToWrite, &holdingBuffer);  
    rb->lastReadIndex = lastFreshSample; 

    NSLog(@"Error = %d, wrote %d bytes", status, numBytesToWrite); 

    return;

什麼是這個錯誤-40？順便說一句，一切如果我寫，直接從ringBuffer到文件工作正常。當然，這聽起來像垃圾，因爲我寫的花車，沒有SInt16s，但AudioFileWriteBytes不抱怨。

來源

2010-03-21 alexbw

的關鍵是輸入數據的字節序明確更改爲大端。我所要做的就是包裝CFSwapInt16HostToBig在我的數據獲取：

float audioVal = rb->data[(i + rb->lastReadIndex) & buffLen]; 
holdingBuffer[i] = CFSwapInt16HostToBig((SInt16) audioVal);

來源

2010-03-23 01:42:32 alexbw

AudioFileWriteBytes失敗，錯誤代碼-40

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