Function calculateNormalizationScale

src/core/ConvolverNode.cpp:46–80

const float MinPower = 0.000125f;

static float calculateNormalizationScale(AudioBus * response)
{
    // Normalize by RMS power
    size_t numberOfChannels = response->numberOfChannels();
    int length = response->length();

    float power = 0;

    for (int i = 0; i < numberOfChannels; ++i)
    {
        float channelPower = 0;
        VectorMath::vsvesq(response->channel(i)->data(), 1, &channelPower, length);
        power += channelPower;
    }

    power = sqrt(power / (numberOfChannels * length));

    // Protect against accidental overload
    if (isinf(power) || isnan(power) || power < MinPower)
        power = MinPower;

    float scale = 1 / power;

    scale *= powf(10, GainCalibration * 0.05f);  // calibrate to make perceived volume same as unprocessed

    // Scale depends on sample-rate.
    if (response->sampleRate())
        scale *= GainCalibrationSampleRate / response->sampleRate();

    // True-stereo compensation
    if (response->numberOfChannels() == Channels::Quad)
        scale *= 0.5f;

    return scale;
}

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