wavfile.cpp Example File

multimedia/spectrum/app/wavfile.cpp
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#include <qendian.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; }