creating app server that read from microphone, send to socket, and on client play audio

zabitqt

Hi, my problem is the microphone disappear immediately once it start.
Then readyRead signal isn't' emmited.
I edit mythread, it isn't a QThread because I meet some problems with it.

Where I'm wrong?

main.cpp

#include <QCoreApplication>
#include <myserver.h>

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    MyServer server;
    server.startServer();

    return a.exec();
}

myserver.cpp

#include "myserver.h"

MyServer::MyServer()
{
}

void MyServer::startServer()
{
    int port = 12345;

    QString ipAddress;
    QList<QHostAddress> ipAddressesList = QNetworkInterface::allAddresses();

    for (int i = 0; i < ipAddressesList.size(); ++i)
    {
        if (ipAddressesList.at(i) != QHostAddress::LocalHost &&  ipAddressesList.at(i).toIPv4Address())
        {
            ipAddress = ipAddressesList.at(i).toString();
            break;
        }
    }

    if(!this->listen( QHostAddress(ipAddress),port ) )
    {
        qDebug() << "Could not start server";
    }
    else
    {
        qDebug() << "The server is running on\n\nIP: "<< ipAddress;
        qDebug() << "\nport: " << this->serverPort() << "\n\n";
    }
}

void MyServer::incomingConnection(int socketDescriptor)
{
    qDebug() << socketDescriptor << " Connecting...";
    
    audioInput = NULL;

    MyThread1 *thread = new MyThread1(socketDescriptor);
    thread->moveToThread(QCoreApplication::instance()->thread());
    thread->setParent(QCoreApplication::instance()->thread());
    //connect(thread, SIGNAL(finished()), thread, SLOT(deleteLater()));
    thread->run();
}

mythread.cpp

#include "mythread.h"
#include <QCoreApplication>
#include <QBuffer>
MyThread1::MyThread1( int ID)
{
    this->socketDescriptor = ID;
    this->speaker = NULL;
}

void MyThread1::run()
{
    qDebug() << " Thread started";




    socket = new QTcpSocket();

    if(!socket->setSocketDescriptor(this->socketDescriptor))
    {
        emit error(socket->error());
        return;
    }

    QAudioFormat format;

    format.setSampleRate(44100);
    format.setChannelCount(1);
    format.setSampleSize(16);
    format.setCodec("audio/pcm");
    format.setByteOrder(QAudioFormat::LittleEndian);
    format.setSampleType(QAudioFormat::UnSignedInt);

    QAudioDeviceInfo info = QAudioDeviceInfo::defaultInputDevice();
    if (!info.isFormatSupported(format))
    {
        qWarning()<<"default format not supported try to use nearest";
        format = info.nearestFormat(format);
    }

    this->speaker = new QAudioInput(format, socket);

    QBuffer mInputBuffer;
    mInputBuffer.open(QBuffer::ReadWrite);
    QIODevice *dev = speaker->start();
    connect(dev, SIGNAL( readyRead() ), this, SLOT( sendData() ) , Qt::DirectConnection);

    qDebug() << socketDescriptor << " Microphone connected";
}

void MyThread1::onfinishThread(){
    qDebug()<<"thread is finished!";
}

void MyThread1::sendData()
{
    qDebug() << " Thread sendData";

    QByteArray Data = speaker->start()->readAll();
    //QDataStream l_vStream(&Data, QIODevice::WriteOnly);

    //l_vStream.setByteOrder(QDataStream::LittleEndian);

    socket->write(Data, Data.length());
    socket->waitForBytesWritten();
}

void MyThread1::disconnected( )
{
    qDebug() << socketDescriptor << "Mic Disconnected";

    speaker->stop();
    delete speaker;

    socket->deleteLater();
    exit(0);
}

Axel Spoerl

It would be good, if you'd also show your class definitions/header files and let us know which Qt version you use.
Regarding style, you initialize your members socketDescriptor and speaker using the this pointer. You also call your member functions with this->. Why? That's unnecessary and confusing. Since the class member speaker is a QAudioInput *, initialize it with nullptr instead of NULL.

Hi, my problem is the microphone disappear immediately once it start.
What do you mean by "disappear"?

this->speaker = new QAudioInput(format, socket);
Here you create a new audio input and store it in the member speaker. Leave out the this-> and consider renaming the member variable into microphone, the opposite of a speaker. But that is what you actually mean.

QBuffer mInputBuffer;
mInputBuffer.open(QBuffer::ReadWrite);

=> What's that? These two lines will have no effect at all.

QIODevice *dev = speaker->start();
=> Now you start the audio input device called "speaker" and being a microphone. You obtain the pointer to a QIODevice and store it locally in dev. That way, the pointer to the IO device is forgotten when dev goes out of scope. dev should be a class member, not a local variable.

connect(dev, SIGNAL( readyRead() ), this, SLOT( sendData() ) , Qt::DirectConnection);
=> Well done... But you could wrap the line in a Q_ASSERT() as long as you debug. That way your application will fail here, if connect goes wrong.

Then readyRead signal isn't' emmited.

=>That probably has two reasons.

I edit mythread, it isn't a QThread because I meet some problems with it.

Why not a QThread? And what are you using instead to make sure that an event loop is running and taking care of your signal / slot connection? Without an event loop, your signal/slot connections will never be executed.

Where I'm wrong?

QByteArray Data = speaker->start()->readAll();
=> Here.
You need to access the IO device by the pointer you obtain upon your first start() call. If you call start() again (probably in the assumption you just re-obtain the previous pointer), you actually discard the input that has fired the signal and create a new IO device. That's why you have to make dev a member, initialize it with nullptr and use it here:

if (!dev) {
    qDebug() << "IO error";
    return;
}

QByteArray Data = dev->readAll();
// continue with your code

zabitqt

I did what you told me.
Output now is something like this: Thread sendData

So, data is sent throught socket but microphone icon in bottom windows bar disappears. and it no send other data.

Axel Spoerl

Please share your header files, operating system and Qt version with us.
Unless you have already, #include <QDebug>and add the following line to after each of the statements speaker->start()and QByteArray Data = dev->readAll();:

qDebug() << speaker->state() << speaker->error();

Let us know what the output is.

You could also append Data to a file and dump it to a QAudioSinkto see what it contains.

zabitqt

Qt 5.12 and Microsoft Windows 10 Operating system
I solve with

this->dev = mic->start()

in connect function

now it emit correctly readyRead signal many times.
I can't however play row audio sound on client socket

Later I will share header files and client socket source code.

meanwhile thank you very much

Axel Spoerl

Why this->before the dev?

SimonSchroeder

@Axel-Spoerl said in creating app server that read from microphone, send to socket, and on client play audio:

Why this->before the dev?

I don't understand why you are promoting dropping this. (Just to be clear, I don't use it; mostly because I'm too lazy to type it). It is a valid style choice. Also, it makes clear that you want to access a member variable (same for member function calls). It even helps to catch errors if you apply this style consistently: If you don't have that member variable, it will fail to compile. If you introduce a local variable with the same name by accident, it will still to the right thing. Usually, being more explicit is considered better style.

Let's not fight over style in this forum. @zabitqt might have his reasons why he chose this style. If he's still a beginner, you might even confuse him. This is unnecessary and does not help to solve his problems.

zabitqt

in class I declared
QIODevice *dev;

In class constructor
this.->dev = nullptr;

In method it return instance of QIODevice *
this->dev = mic->start();

or simple
dev = mic->start();

I use "this->" to differentiate class variables from local method variables but I could have use only dev.

Axel Spoerl

Can you please share your entire class definition / header file with us?
Sorry for asking about this- we don't know what your thisactually is.
Do you subclass QObject? Or QThread? Have you overridden virtual methods, e.g. QThread's run()?
Have you added the debug statements I proposed and if so, what's their output?