1、概述
源码放在文章末尾
该文章实现了简单的语音识别功能，首先，语音识别要做三件事情 ：
1.记录用户的语音文件到本地
2.将用户语音编码 使用flac或者speex进行编码
3.使用第三方语音识别API或者SDK进行分析识别语音 目前做的比较简单就是使用flac文件对wav音频文件进行编码 基于Mac OSX和Win 7平台的 win 7下使用flac.exe，具体exe帮助，读者可以使用flac.exe --help > help.txt 重定向到一个help文件中，方便查阅. mac osx下面安装flac.dmg的安装包即可使用flac命令 我们先看音频的录入 Qt集成了音频模块
项目部分代码如下所示：
/*
* Based on Qt Example
* PCM2WAV is not mine, I found it in Google and modified it.
*/
#ifndef SPEECHINPUT
#define SPEECHINPUT
#include <QPixmap>
#include <QWidget>
#include <QObject>
#include <QPushButton>
#include <QByteArray>
//#include <Phonon/AudioOutput>
#include <QtMultimedia>
#include <QIODevice>
#include <QFile>
class WavPcmFile : public QFile {
public:
WavPcmFile(const QString & name, const QAudioFormat & format, QObject *parent = 0);
bool open();
void close();
private:
void writeHeader();
bool hasSupportedFormat();
QAudioFormat format;
};
class AudioInfo : public QIODevice
{
Q_OBJECT
public:
AudioInfo(const QAudioFormat &format, QObject *parent, const QString &filename = "./data/tmp/speechInput.wav");
~AudioInfo();
void start();
void stop();
qreal level() const { return m_level; }
qint64 readData(char *data, qint64 maxlen);
qint64 writeData(const char *data, qint64 len);
private:
const QAudioFormat m_format;
quint16 m_maxAmplitude;
qreal m_level; // 0.0 <= m_level <= 1.0
WavPcmFile * m_file;
signals:
void update();
};
class RenderArea : public QPushButton
{
Q_OBJECT
public:
RenderArea(QWidget *parent = 0);
void setLevel(qreal value);
protected:
void paintEvent(QPaintEvent *event);
private:
qreal m_level;
QPixmap m_pixmap;
};
#endif
/*
* Based on Qt Example
* PCM2WAV is not mine, I found it in Google and modified it.
*/
#include "speechInput.h"
#include <QtEndian>
#include <QDebug>
#include <QPainter>
WavPcmFile::WavPcmFile(const QString & name, const QAudioFormat & format_, QObject *parent_)
: QFile(name, parent_), format(format_)
{
}
bool WavPcmFile::hasSupportedFormat()
{
return (format.sampleSize() == 8
&& format.sampleType() == QAudioFormat::UnSignedInt)
|| (format.sampleSize() > 8
&& format.sampleType() == QAudioFormat::SignedInt
&& format.byteOrder() == QAudioFormat::LittleEndian);
}
bool WavPcmFile::open()
{
if (!hasSupportedFormat()) {
setErrorString("Wav PCM supports only 8-bit unsigned samples "
"or 16-bit (or more) signed samples (in little endian)");
return false;
} else {
if (!QFile::open(ReadWrite | Truncate))
return false;
writeHeader();
return true;
}
}
void WavPcmFile::writeHeader()
{
QDataStream out(this);
out.setByteOrder(QDataStream::LittleEndian);
// RIFF chunk
out.writeRawData("RIFF", 4);
out << quint32(0); // Placeholder for the RIFF chunk size (filled by close())
out.writeRawData("WAVE", 4);
// Format description chunk
out.writeRawData("fmt ", 4);
out << quint32(16); // "fmt " chunk size (always 16 for PCM)
out << quint16(1); // data format (1 => PCM)
out << quint16(format.channelCount());
out << quint32(format.sampleRate());
out << quint32(format.sampleRate() * format.channelCount()
* format.sampleSize() / 8 ); // bytes per second
out << quint16(format.channelCount() * format.sampleSize() / 8); // Block align
out << quint16(format.sampleSize()); // Significant Bits Per Sample
// Data chunk
out.writeRawData("data", 4);
out << quint32(0); // Placeholder for the data chunk size (filled by close())
Q_ASSERT(pos() == 44); // Must be 44 for WAV PCM
}
void WavPcmFile::close()
{
// Fill the header size placeholders
quint32 fileSize = size();
QDataStream out(this);
// RIFF chunk size
seek(4);
out << quint32(fileSize - 8);
// data chunk size
seek(40);
out << quint32(fileSize - 44);
QFile::close();
}
AudioInfo::AudioInfo(const QAudioFormat &format, QObject *parent, const QString &filename)
: QIODevice(parent)
, m_format(format)
, m_maxAmplitude(0)
, m_level(0.0)
{
switch (m_format.sampleSize()) {
case 8:
switch (m_format.sampleType()) {
case QAudioFormat::UnSignedInt:
m_maxAmplitude = 255;
break;
case QAudioFormat::SignedInt:
m_maxAmplitude = 127;
break;
default:
break;
}
break;
case 16:
switch (m_format.sampleType()) {
case QAudioFormat::UnSignedInt:
m_maxAmplitude = 65535;
break;
case QAudioFormat::SignedInt:
m_maxAmplitude = 32767;
break;
default:
break;
}
break;
default:
break;
}
m_file = new WavPcmFile(filename,format,this);
}
AudioInfo::~AudioInfo()
{
}
void AudioInfo::start()
{
m_file->open();
open(QIODevice::WriteOnly);
}
void AudioInfo::stop()
{
close();
m_file->close();
}
qint64 AudioInfo::readData(char *data, qint64 maxlen)
{
Q_UNUSED(data)
Q_UNUSED(maxlen)
return 0;
}
qint64 AudioInfo::writeData(const char *data, qint64 len)
{
if (m_maxAmplitude) {
Q_ASSERT(m_format.sampleSize() % 8 == 0);
const int channelBytes = m_format.sampleSize() / 8;
const int sampleBytes = m_format.channelCount() * channelBytes;
Q_ASSERT(len % sampleBytes == 0);
const int numSamples = len / sampleBytes;
quint16 maxValue = 0;
const unsigned char *ptr = reinterpret_cast<const unsigned char *>(data);
for (int i = 0; i < numSamples; ++i) {
for(int j = 0; j < m_format.channelCount(); ++j) {
quint16 value = 0;
if (m_format.sampleSize() == 8 && m_format.sampleType() == QAudioFormat::UnSignedInt) {
value = *reinterpret_cast<const quint8*>(ptr);
} else if (m_format.sampleSize() == 8 && m_format.sampleType() == QAudioFormat::SignedInt) {
value = qAbs(*reinterpret_cast<const qint8*>(ptr));
} else if (m_format.sampleSize() == 16 && m_format.sampleType() == QAudioFormat::UnSignedInt) {
if (m_format.byteOrder() == QAudioFormat::LittleEndian)
value = qFromLittleEndian<quint16>(ptr);
else
value = qFromBigEndian<quint16>(ptr);
} else if (m_format.sampleSize() == 16 && m_format.sampleType() == QAudioFormat::SignedInt) {
if (m_format.byteOrder() == QAudioFormat::LittleEndian)
value = qAbs(qFromLittleEndian<qint16>(ptr));
else
value = qAbs(qFromBigEndian<qint16>(ptr));
}
maxValue = qMax(value, maxValue);
ptr += channelBytes;
}
}
maxValue = qMin(maxValue, m_maxAmplitude);
m_level = qreal(maxValue) / m_maxAmplitude;
}
m_file->write(data,len);
emit update();
return len;
}
RenderArea::RenderArea(QWidget *parent)
: QPushButton(parent)
{
setBackgroundRole(QPalette::Base);
setAutoFillBackground(true);
m_level = 0;
setMinimumHeight(30);
setMinimumWidth(80);
}
void RenderArea::paintEvent(QPaintEvent * /* event */)
{
QPainter painter(this);
QPixmap pixmap = QPixmap(":/images/button_default.png").scaled(this->size());
painter.drawPixmap(this->rect(), pixmap);
// painter.setPen(Qt::black);
// painter.drawRect(QRect(painter.viewport().left(),
// painter.viewport().top(),
// painter.viewport().right()-20,
// painter.viewport().bottom()-20));
if (m_level == 0.0)
return;
painter.setPen(Qt::darkGray);
int pos = ((painter.viewport().right()-20)-(painter.viewport().left()+11))*m_level;
for (int i = 0; i < 10; ++i) {
int x1 = painter.viewport().left()+11;
int y1 = painter.viewport().top()+10+i;
int x2 = painter.viewport().left()+20+pos;
int y2 = painter.viewport().top()+10+i;
if (x2 < painter.viewport().left()+10)
x2 = painter.viewport().left()+10;
painter.drawLine(QPoint(x1+10, y1+10),QPoint(x2+10, y2+10));
}
}
void RenderArea::setLevel(qreal value)
{
m_level = value;
repaint();
}