iPhone:AudioBufferList 初始化和释放

Question

初始化(分配内存)和释放(释放)具有 3 个 AudioBuffers 的 AudioBufferList 的正确方法是什么？ (我知道可能有不止一种方法可以做到这一点。)

我想使用这 3 个缓冲区将音频文件的顺序部分读入其中，并使用音频单元播放它们。

Answer 1

这是我的做法:

AudioBufferList *
AllocateABL(UInt32 channelsPerFrame, UInt32 bytesPerFrame, bool interleaved, UInt32 capacityFrames)
{
    AudioBufferList *bufferList = NULL;

    UInt32 numBuffers = interleaved ? 1 : channelsPerFrame;
    UInt32 channelsPerBuffer = interleaved ? channelsPerFrame : 1;

    bufferList = static_cast<AudioBufferList *>(calloc(1, offsetof(AudioBufferList, mBuffers) + (sizeof(AudioBuffer) * numBuffers)));

    bufferList->mNumberBuffers = numBuffers;

    for(UInt32 bufferIndex = 0; bufferIndex < bufferList->mNumberBuffers; ++bufferIndex) {
        bufferList->mBuffers[bufferIndex].mData = static_cast<void *>(calloc(capacityFrames, bytesPerFrame));
        bufferList->mBuffers[bufferIndex].mDataByteSize = capacityFrames * bytesPerFrame;
        bufferList->mBuffers[bufferIndex].mNumberChannels = channelsPerBuffer;
    }

    return bufferList;
}