objective-c - 使用vDSP_ctoz()和vDSP_ztoz()进行解交错和交错缓冲器？

如何将float *newAudio解交织成float *channel1和float* channel2，然后又交织成newAudio？

Novocaine *audioManager = [Novocaine audioManager];

__block float *channel1;
__block float *channel2;
[audioManager setInputBlock:^(float *newAudio, UInt32 numSamples, UInt32 numChannels) {
  // Audio comes in interleaved, so,
  // if numChannels = 2, newAudio[0] is channel 1, newAudio[1] is channel 2, newAudio[2] is channel 1, etc.

      // Deinterleave with vDSP_ctoz()/vDSP_ztoz(); and fill channel1 and channel2
      // ... processing on channel1 & channel2
      // Interleave channel1 and channel2 with vDSP_ctoz()/vDSP_ztoz(); to newAudio
}];

这两行代码是什么样的？我不了解ctoz/ztoz的语法。

最佳答案

我在Novocaine的辅助类(如Ringbuffer)中进行去交织的操作:

float zero = 0.0;
vDSP_vsadd(data, numChannels, &zero, leftSampleData, 1, numFrames);
vDSP_vsadd(data+1, numChannels, &zero, rightSampleData, 1, numFrames);

用于交织:

float zero = 0.0;
vDSP_vsadd(leftSampleData, 1, &zero, data, numChannels, numFrames);
vDSP_vsadd(rightSampleData, 1, &zero, data+1, numChannels, numFrames);

做事的更一般的方法是拥有一个数组数组，例如

int maxNumChannels = 2;
int maxNumFrames = 1024;
float **arrays = (float **)calloc(maxNumChannels, sizeof(float *));
for (int i=0; i < maxNumChannels; ++i) {
    arrays[i] = (float *)calloc(maxNumFrames, sizeof(float));
}

[[Novocaine audioManager] setInputBlock:^(float *data, UInt32 numFrames, UInt32 numChannels) {
    float zero = 0.0;
    for (int iChannel = 0; iChannel < numChannels; ++iChannel) {
        vDSP_vsadd(data, numChannels, &zero, arrays[iChannel], 1, numFrames);
    }
}];

这是我在Novocaine的RingBuffer附件类中内部大量使用的功能。我对vDSP_vsadd和memcpy的速度进行了计时，(非常，非常令人惊讶)，没有速度差异。

当然，您始终可以只使用环形缓冲区，从而省去了麻烦

#import "RingBuffer.h"

int maxNumFrames = 4096
int maxNumChannels = 2
RingBuffer *ringBuffer = new RingBuffer(maxNumFrames, maxNumChannels)

[[Novocaine audioManager] setInputBlock:^(float *data, UInt32 numFrames, UInt32 numChannels) {
    ringBuffer->AddNewInterleavedFloatData(data, numFrames, numChannels);
}];

[[Novocaine audioManager] setOuputBlock:^(float *data, UInt32 numFrames, UInt32 numChannels) {
    ringBuffer->FetchInterleavedData(data, numFrames, numChannels);
}];

希望能有所帮助。

关于objective-c - 使用vDSP_ctoz()和vDSP_ztoz()进行解交错和交错缓冲器？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/10361974/