wavfile.cpp Example File

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  #include <qendian.h>
  #include <QVector>
  #include <QDebug>
  #include "utils.h"
  #include "wavfile.h"

  struct chunk
  {
      char        id[4];
      quint32     size;
  };

  struct RIFFHeader
  {
      chunk       descriptor;     // "RIFF"
      char        type[4];        // "WAVE"
  };

  struct WAVEHeader
  {
      chunk       descriptor;
      quint16     audioFormat;
      quint16     numChannels;
      quint32     sampleRate;
      quint32     byteRate;
      quint16     blockAlign;
      quint16     bitsPerSample;
  };

  struct DATAHeader
  {
      chunk       descriptor;
  };

  struct CombinedHeader
  {
      RIFFHeader  riff;
      WAVEHeader  wave;
  };

  WavFile::WavFile(QObject *parent)
      : QFile(parent)
      , m_headerLength(0)
  {

  }

  bool WavFile::open(const QString &fileName)
  {
      close();
      setFileName(fileName);
      return QFile::open(QIODevice::ReadOnly) && readHeader();
  }

  const QAudioFormat &WavFile::fileFormat() const
  {
      return m_fileFormat;
  }

  qint64 WavFile::headerLength() const
  {
  return m_headerLength;
  }

  bool WavFile::readHeader()
  {
      seek(0);
      CombinedHeader header;
      bool result = read(reinterpret_cast<char *>(&header), sizeof(CombinedHeader)) == sizeof(CombinedHeader);
      if (result) {
          if ((memcmp(&header.riff.descriptor.id, "RIFF", 4) == 0
              || memcmp(&header.riff.descriptor.id, "RIFX", 4) == 0)
              && memcmp(&header.riff.type, "WAVE", 4) == 0
              && memcmp(&header.wave.descriptor.id, "fmt ", 4) == 0
              && (header.wave.audioFormat == 1 || header.wave.audioFormat == 0)) {

              // Read off remaining header information
              DATAHeader dataHeader;

              if (qFromLittleEndian<quint32>(header.wave.descriptor.size) > sizeof(WAVEHeader)) {
                  // Extended data available
                  quint16 extraFormatBytes;
                  if (peek((char*)&extraFormatBytes, sizeof(quint16)) != sizeof(quint16))
                      return false;
                  const qint64 throwAwayBytes = sizeof(quint16) + qFromLittleEndian<quint16>(extraFormatBytes);
                  if (read(throwAwayBytes).size() != throwAwayBytes)
                      return false;
              }

              if (read((char*)&dataHeader, sizeof(DATAHeader)) != sizeof(DATAHeader))
                  return false;

              // Establish format
              if (memcmp(&header.riff.descriptor.id, "RIFF", 4) == 0)
                  m_fileFormat.setByteOrder(QAudioFormat::LittleEndian);
              else
                  m_fileFormat.setByteOrder(QAudioFormat::BigEndian);

              int bps = qFromLittleEndian<quint16>(header.wave.bitsPerSample);
              m_fileFormat.setChannelCount(qFromLittleEndian<quint16>(header.wave.numChannels));
              m_fileFormat.setCodec("audio/pcm");
              m_fileFormat.setSampleRate(qFromLittleEndian<quint32>(header.wave.sampleRate));
              m_fileFormat.setSampleSize(qFromLittleEndian<quint16>(header.wave.bitsPerSample));
              m_fileFormat.setSampleType(bps == 8 ? QAudioFormat::UnSignedInt : QAudioFormat::SignedInt);
          } else {
              result = false;
          }
      }
      m_headerLength = pos();
      return result;
  }