/home/maxime/Projets/Mixxx/1.10/mixxx/src/engine/enginevumeter.cpp

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/***************************************************************************
                          enginevumeter.cpp  -  description
                             -------------------
    copyright            : (C) 2002 by Tue and Ken Haste Andersen
    email                :
***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/

#ifdef __WINDOWS__
#pragma intrinsic(fabs)
#endif

#include "engine/enginevumeter.h"
#include "controlpotmeter.h"
#include "sampleutil.h"

EngineVuMeter::EngineVuMeter(const char * group) {
    // The VUmeter widget is controlled via a controlpotmeter, which means
    // that it should react on the setValue(int) signal.
    m_ctrlVuMeter = new ControlPotmeter(ConfigKey(group, "VuMeter"), 0., 1.);
    m_ctrlVuMeter->set(0);
    // left channel VU meter
    m_ctrlVuMeterL = new ControlPotmeter(ConfigKey(group, "VuMeterL"), 0., 1.);
    m_ctrlVuMeterL->set(0);
    // right channel VU meter
    m_ctrlVuMeterR = new ControlPotmeter(ConfigKey(group, "VuMeterR"), 0., 1.);
    m_ctrlVuMeterR->set(0);

    // Initialize the calculation:
    m_iSamplesCalculated = 0;
    m_fRMSvolumeL = 0;
    m_fRMSvolumeSumL = 0;
    m_fRMSvolumeR = 0;
    m_fRMSvolumeSumR = 0;
}

EngineVuMeter::~EngineVuMeter()
{
    delete m_ctrlVuMeter;
    delete m_ctrlVuMeterL;
    delete m_ctrlVuMeterR;
}

void EngineVuMeter::process(const CSAMPLE * pIn, const CSAMPLE *, const int iBufferSize)
{

    CSAMPLE fVolSumL, fVolSumR;
    SampleUtil::sumAbsPerChannel(&fVolSumL, &fVolSumR, pIn, iBufferSize);
    m_fRMSvolumeSumL += fVolSumL;
    m_fRMSvolumeSumR += fVolSumR;

    m_iSamplesCalculated += iBufferSize/2;

    // Are we ready to update the VU meter?:
    if (m_iSamplesCalculated > (44100/2/UPDATE_RATE) )
    {
        doSmooth(m_fRMSvolumeL, log10(m_fRMSvolumeSumL/(m_iSamplesCalculated*1000)+1));
        doSmooth(m_fRMSvolumeR, log10(m_fRMSvolumeSumR/(m_iSamplesCalculated*1000)+1));

        const double epsilon = .0001;

        // Since VU meters are a rolling sum of audio, the no-op checks in
        // ControlObject will not prevent us from causing tons of extra
        // work. Because of this, we use an epsilon here to be gentle on the GUI
        // and MIDI controllers.
        if (fabs(m_fRMSvolumeL - m_ctrlVuMeterL->get()) > epsilon)
            m_ctrlVuMeterL->set(m_fRMSvolumeL);
        if (fabs(m_fRMSvolumeR - m_ctrlVuMeterR->get()) > epsilon)
            m_ctrlVuMeterR->set(m_fRMSvolumeR);

        double fRMSvolume = (m_fRMSvolumeL + m_fRMSvolumeR) / 2.0;
        if (fabs(fRMSvolume - m_ctrlVuMeter->get()) > epsilon)
            m_ctrlVuMeter->set(fRMSvolume);

        // Reset calculation:
        m_iSamplesCalculated = 0;
        m_fRMSvolumeSumL = 0;
        m_fRMSvolumeSumR = 0;
    }
}


void EngineVuMeter::doSmooth(FLOAT_TYPE &currentVolume, FLOAT_TYPE newVolume)
{
    if (currentVolume > newVolume)
        currentVolume -= DECAY_SMOOTHING * (currentVolume - newVolume);
    else
        currentVolume += ATTACK_SMOOTHING * (newVolume - currentVolume);
    if (currentVolume < 0)
        currentVolume=0;
    if (currentVolume > 1.0)
        currentVolume=1.0;
}