Que: How to play PCM data in Qt?

[santa1367]

Explanation: I have character array and I want paly it by using Qt.
I am using following code. But its playing something garbage voice.

1. My_Audio.h

#ifndef MYAUDIO
#define MYAUDIO

#endif // MYAUDIO


#include <QDebug>
#include <QIODevice>
#include <QAudioInput>
#include <QAudioOutput>
#include <QCoreApplication>
#include <QWidget>

//#define SAMPLE_RATE 22050
#define SAMPLE_RATE 22050
#define CHANNELS 1
#define SAMPLE_SIZE 16

#define SAMPLE_TYPE SignedInt

const float DurationSeconds = 0.1;
const int ToneFrequencyHz = 4000;
const int DataFrequencyHz = 44100;
const int BufferSize   = 131072;

class myAudio
{
 // Q_OBJECT

public:
    QAudioOutput *audioOut;
    QAudioInput  *audioIn;
    QWidget *parent;


    myAudio(QWidget *parent);
   ~myAudio(){}
   void fillBuffer();
    QAudioFormat formatIn,formatOut;
    QByteArray buff;
     QAudioDeviceInfo deviceinfo;
    QIODevice*            auIObuffer;     // IODevice to connect to m_AudioOutput
    signed short   aubuffer[BufferSize];     // Audio circular buffer
    int                      readpointer;           // Pointer to the portion of the audio buffer
                                                 // to be read.
    int                      writepointer;

public slots:
    void write();
};

2. My_Audio.cpp

#include "myAudio.h"
#include <QDebug>
#include <windows.h>
#include <qmath.h>
#include <qEndian.h>
#include <QFile>

myAudio::myAudio(QWidget *parent)
{
   formatOut.setSampleRate(SAMPLE_RATE);
   formatOut.setChannelCount(CHANNELS);
   formatOut.setSampleSize(SAMPLE_SIZE);
   formatOut.setCodec("audio/pcm");
   formatOut.setByteOrder(QAudioFormat::LittleEndian);
   formatOut.setSampleType(QAudioFormat::SAMPLE_TYPE);

//print out the output device setup parameters

   deviceinfo = QAudioDeviceInfo::defaultOutputDevice(); // Device info = default

   if(!deviceinfo.isFormatSupported(formatOut))
   {
       qDebug() << "\nformat specifieed not supported";
   }

      audioOut=0;
      audioOut = new QAudioOutput(deviceinfo, formatOut, parent);
      audioOut->setNotifyInterval(10);
      audioOut->setBufferSize(131072); //in bytes
      QObject::connect(audioOut, SIGNAL(notify()), parent, SLOT(write()));
   //auIObuffer->open(QIODevice::ReadOnly);
      auIObuffer = audioOut->start();


//   print out the device specifications
    foreach(const QAudioDeviceInfo &deviceInfo, QAudioDeviceInfo::availableDevices(QAudio::AudioOutput))
        {
        qDebug() << "\nSuported output devices";
        qDebug() << "Device name: "             << deviceInfo.deviceName();
        qDebug() << "Supported channel count: "   << deviceInfo.supportedChannelCounts();
        qDebug() << "Supported Codec: "           << deviceInfo.supportedCodecs();
        qDebug() << "Supported byte order: "      << deviceInfo.supportedByteOrders();
        qDebug() << "Supported Sample Rate: "     << deviceInfo.supportedSampleRates();
        qDebug() << "Supported Sample Size: "     << deviceInfo.supportedSampleSizes();
        qDebug() << "Supported Sample Type: "     << deviceInfo.supportedSampleTypes();
        qDebug() << "Preferred Device settings:"  << deviceInfo.preferredFormat();
        }

     for (int sample=0; sample<BufferSize; sample++) {
          signed short value=0;
          if ((sample>20000) && (sample<20000+(DurationSeconds*DataFrequencyHz))){
            float time = (float) sample/DataFrequencyHz ;
            float x = qSin(2 * M_PI *ToneFrequencyHz* time);
            value = static_cast<signed short>(x * 32767);
          }
          aubuffer[sample] = value;
     }
     writepointer=0;
     readpointer=0;
     write();
}

void myAudio::write()
{
   int emptyBytes = audioOut->bytesFree(); // Check how many empty bytes are in the device buffer
   int periodSize = audioOut->periodSize(); // Check the ideal chunk size, in bytes
   int chunks = emptyBytes/periodSize;
   char *data = "#Dis";	// referring to “This” 
       auIObuffer->write((const char*) data, periodSize);
}

3. MainWindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
   Q_OBJECT

public:
   explicit MainWindow(QWidget *parent = 0);
   ~MainWindow();

private slots:
   void on_pushButton_clicked();

private:
   Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H

4. MainWindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "myaudio.h"
myAudio *m;
MainWindow::MainWindow(QWidget *parent) :
   QMainWindow(parent),
   ui(new Ui::MainWindow)
{
   ui->setupUi(this);

m = new myAudio(parent);

}

MainWindow::~MainWindow()
{
   delete ui;
}

void MainWindow::on_pushButton_clicked()
{
   m->write();
}

5. Main.cpp

#include "mainwindow.h"
#include <QApplication>

int main(int argc, char *argv[])
{
   QApplication a(argc, argv);
   MainWindow w;
   w.show();

   return a.exec();
}

6. ProjectName.Pro

QT       += core gui
QT += multimedia widgets
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = ProjectName
TEMPLATE = app
CONFIG   -= app_bundle

SOURCES += main.cpp\
       mainwindow.cpp \
   myaudio.cpp

HEADERS  += mainwindow.h \
   myaudio.h

FORMS    += mainwindow.ui

Please help me on this.

[santa1367]

It worked.

Was doing mistake by providing actually speech content to write buffer api.
Instead of speech content, actual PCM data need to be given.
And Thanks to @Chris Kawa for editing post to make it more readable