Qt 5.7 | Qt Multimedia | Spectrum Example | utils.h Example File

Qt 5.7.1 Reference Documentation

# utils.h Example File

multimedia/spectrum/app/utils.h

      /****************************************************************************
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      ** Contact: http://www.qt.io/licensing/
      **
      ** This file is part of the examples of the Qt Toolkit.
      **
      ** $QT_BEGIN_LICENSE:BSD$
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      #ifndef UTILS_H
      #define UTILS_H

      #include <QtCore/qglobal.h>
      #include <QDebug>

      QT_FORWARD_DECLARE_CLASS(QAudioFormat)

      //-----------------------------------------------------------------------------
      // Miscellaneous utility functions
      //-----------------------------------------------------------------------------

      qint64 audioDuration(const QAudioFormat &format, qint64 bytes);
      qint64 audioLength(const QAudioFormat &format, qint64 microSeconds);

      QString formatToString(const QAudioFormat &format);

      qreal nyquistFrequency(const QAudioFormat &format);

      // Scale PCM value to [-1.0, 1.0]
      qreal pcmToReal(qint16 pcm);

      // Scale real value in [-1.0, 1.0] to PCM
      qint16 realToPcm(qreal real);

      // Check whether the audio format is PCM
      bool isPCM(const QAudioFormat &format);

      // Check whether the audio format is signed, little-endian, 16-bit PCM
      bool isPCMS16LE(const QAudioFormat &format);

      // Compile-time calculation of powers of two

      template<int N> class PowerOfTwo
      { public: static const int Result = PowerOfTwo<N-1>::Result * 2; };

      template<> class PowerOfTwo<0>
      { public: static const int Result = 1; };

      //-----------------------------------------------------------------------------
      // Debug output
      //-----------------------------------------------------------------------------

      class NullDebug
      {
      public:
          template <typename T>
          NullDebug& operator<<(const T&) { return *this; }
      };

      inline NullDebug nullDebug() { return NullDebug(); }

      #ifdef LOG_ENGINE
      #   define ENGINE_DEBUG qDebug()
      #else
      #   define ENGINE_DEBUG nullDebug()
      #endif

      #ifdef LOG_SPECTRUMANALYSER
      #   define SPECTRUMANALYSER_DEBUG qDebug()
      #else
      #   define SPECTRUMANALYSER_DEBUG nullDebug()
      #endif

      #ifdef LOG_WAVEFORM
      #   define WAVEFORM_DEBUG qDebug()
      #else
      #   define WAVEFORM_DEBUG nullDebug()
      #endif

      #endif // UTILS_H