從FFT樣本計算頻率？

Question

我正在虛幻引擎4中使用以下代碼來捕獲麥克風輸入並獲得結果FFT。

我無法根據此數據計算頻率。

我試圖找到最大振幅並將其作為頻率，但這似乎並不正確。

// Additional includes:
#include "Voice.h"
#include "OnlineSubsystemUtils.h"

// New class member:
TSharedPtr<class IVoiceCapture> voiceCapture;

// Initialisation:
voiceCapture = FVoiceModule::Get().CreateVoiceCapture();
voiceCapture->Start();

// Capturing samples:
uint32 bytesAvailable = 0;
EVoiceCaptureState::Type captureState = voiceCapture->GetCaptureState(bytesAvailable);
if (captureState == EVoiceCaptureState::Ok && bytesAvailable > 0)
{
    uint8 buf[maxBytes];
    memset(buf, 0, maxBytes);
    uint32 readBytes = 0;
    voiceCapture->GetVoiceData(buf, maxBytes, readBytes);

    uint32 samples = readBytes / 2;
    float* sampleBuf = new float[samples];

    int16_t sample;
    for (uint32 i = 0; i < samples; i++)
    {
        sample = (buf[i * 2 + 1] << 8) | buf[i * 2];
        sampleBuf[i] = float(sample) / 32768.0f;
    }

    // Do fun stuff here

    delete[] sampleBuf;
}

Answer 1

我看不到要在您的代碼段中執行傅立葉變換。 無論如何，使用DFT以平均采樣頻率R給定N個采樣，對應於bin k的頻率為k·R / 2N