使用ExtAudioFile结合循环缓冲区读取数据时会出现故障。

Question

我正在尝试处理使用ExtAudioFile读取的音频数据。然而，当我试图将这些数据放入循环缓冲区时，我会听到一些小故障。

在下面的示例代码中，我直接将数据从"inBuffer“传递给"outBuffer”( Michael的两种类型的TPCircularBuffer )。两个缓冲器都是大小为10×numberOfFrames * sizeof(float)的。客户端流格式是单一的浮点样本。

为什么我在没有处理任何数据的情况下就听到这些故障？没有一个圆形缓冲，声音流很好。我错了什么，或者另一种方法会更好？

static OSStatus recordingCallback(
                                  void*                       inRefCon,
                                  AudioUnitRenderActionFlags* ioActionFlags,
                                  const AudioTimeStamp*       inTimeStamp,
                                  UInt32                      inBusNumber,
                                  UInt32                      inNumberFrames,
                                  AudioBufferList*            ioData){
    PlayAudioFile* player = (__bridge PlayAudioFile*)inRefCon;
    Info *info = (Info *)player.info;


    ExtAudioFileRead(info->extAudioFile, &inNumberFrames, info->inputBuffer);

    if (inNumberFrames == 0) {
        ExtAudioFileSeek(info->extAudioFile, 0);
    }

    // Put data in circular buffer
     TPCircularBufferProduceBytes(info->inBuffer, info->inputBuffer->mBuffers[0].mData, info->inputBuffer->mBuffers[0].mDataByteSize);


    UInt32 frameSize = inNumberFrames*sizeof(float);
    if (info->inBuffer->fillCount >= frameSize) {
        int32_t availableBytes;

        float *tail = TPCircularBufferTail(info->inBuffer, &availableBytes);
        if (availableBytes > frameSize){
            memcpy(info->tempBuffer, tail, frameSize);
            TPCircularBufferConsume(info->inBuffer, frameSize);

            // Currently, data is not processed but just put to the output buffer

            TPCircularBufferProduceBytes(info->outBuffer, info->tempBuffer, frameSize);
        }
    }

    return noErr;
}



static OSStatus renderCallback(
                               void*                       inRefCon,
                               AudioUnitRenderActionFlags* ioActionFlags,
                               const AudioTimeStamp*       inTimeStamp,
                               UInt32                      inBusNumber,
                               UInt32                      inNumberFrames,
                               AudioBufferList*            ioData){
    PlayAudioFile* player = (__bridge PlayAudioFile*)inRefCon;
    Info *info = (Info *)play.info;

    for (int i=0; i < ioData->mNumberBuffers; i++) {
        AudioBuffer buffer = ioData->mBuffers[i];

        if (info->outBuffer->fillCount > ioData->mBuffers[0].mDataByteSize) {

            int32_t availableBytes;
            float *tail = TPCircularBufferTail(info->outBuffer, &availableBytes);

            memcpy(buffer.mData, tail, buffer.mDataByteSize);
            TPCircularBufferConsume(info->outBuffer, buffer.mDataByteSize);

   /* Messaging is not used for this example
            // Notify delegate
            if ([player.delegate respondsToSelector:@selector(player:audioBuffer:bufferSize:)])
            {
                [player.delegate player:player
                            audioBuffer:buffer.mData
                             bufferSize:inNumberFrames];
            }
    */
        }
        else {
            memset((char*)ioData->mBuffers[i].mData, 0, ioData->mBuffers[i].mDataByteSize  * info->clientFormat.mBytesPerFrame);

        }
    }
    return noErr;
}

基于下面的答案的编辑修改了代码，在回调函数之外分配和释放内存，并增加循环缓冲区的大小。不幸的是，声音仍然比没有圆形缓冲器差。这些小故障还有别的原因吗？

Answer 1

不应在音频回调中分配或释放内存。也不应发送目标C信息。

呈现回调应该始终将数据放入缓冲区列表缓冲区。但是，您的代码缺少了一个code语句来执行此操作。在开始呈现回调之前，尝试一个更大的循环缓冲区，并确保它已经足够的预先填充。