我正在尝试创建两个基于 QTcpSocket 的测试应用程序，一个流式传输（未压缩）图像的服务器和一个接收它们的客户端。
我的代码主要取自 Qts Fortune Client Example 和Fortune Server Example。我已经删掉了所有的gui。我的服务器没有打开连接、发送财富然后立即关闭它，而是保持它打开并不断地流式传输我的图像。客户端只是从 QTcpSocket 读取图像然后丢弃它们。
我发送的图像是 800x600 RGB（=1440000 字节），我会尽可能频繁地发送它。每次发送之前都会从文件中读取图像，并且我没有使用任何压缩。
服务器似乎正在按应有的方式发送图像。但是客户端接收它们的速度太慢了，每秒 1-4 帧，而且有时似乎没有接收到任何数据，这反过来又导致我的服务器使用大量内存（因为客户端的读取速度不如服务器正在写入）。
我试过在不同的机器上运行我的服务器和客户端，并且都在一台机器上，两种设置都会产生同样的问题。
在 Linux 机器上运行我的应用程序时，客户端以更高的速率接收图像（认为它是每秒 14 帧）。客户端似乎能够像服务器写入一样快地读取。
任何人都可以帮助阐明这个问题吗？
- 如何加快数据传输速度？（不使用压缩）
- 如何让客户端的读取速度与服务器的写入速度一样快？
- 我怎样才能让它在我的 Windows 机器上保持稳定？（没有突然的停顿......）在客户端的控制台窗口中单击有时似乎会“唤醒”应用程序顺便说一句。^^
这是我的代码：
服务器：
主文件
#include <iostream>
#include <QCoreApplication>
#include "Server.h"
int main(int argc, char *argv[]){
QCoreApplication app(argc, argv);
QString ipaddress = QString(argv[1]);
int port = atoi(argv[2]);
Server* server = new Server(ipaddress, port);
int retVal = app.exec();
return retVal;
}
服务器.h
#ifndef SERVER_H_
#define SERVER_H_
#include <QObject>
QT_BEGIN_NAMESPACE
class QTcpServer;
class QNetworkSession;
class QTcpSocket;
class QTimer;
QT_END_NAMESPACE
class Server : public QObject
{
Q_OBJECT
public:
Server(QString ipAddress, int port, QObject *parent = 0);
private slots:
void newConnectionSlot();
void sendSlot();
private:
QTcpServer *mTcpServer;
QTcpSocket *mTcpSocket;
QTimer *mSendTimer;
};
#endif /* SERVER_H_ */
服务器.cpp
#include "Server.h"
#include <iostream>
#include <QTcpServer>
#include <QTcpSocket>
#include <QTimer>
#include <QDateTime>
#include <QSettings>
#include <highgui.h>
Server::Server(QString ipAddress, int port, QObject *parent) :
QObject(parent), mTcpServer(0), mTcpSocket(0)
{
mTcpServer = new QTcpServer(this);
connect(mTcpServer, SIGNAL(newConnection()), this, SLOT(newConnectionSlot()));
if (!mTcpServer->listen(QHostAddress(ipAddress), port)) {
std::cout << "Unable to start the server: " << mTcpServer->errorString().toStdString() << std::endl;
return;
}
std::cout << "The server is running on\n\nIP: "<< ipAddress.toStdString()
<< "\nport: " << mTcpServer->serverPort() << "\n\nRun the Client now.\n" << std::endl;
}
void Server::newConnectionSlot()
{
mTcpSocket = mTcpServer->nextPendingConnection();
connect(mTcpSocket, SIGNAL(disconnected()),
mTcpSocket, SLOT(deleteLater()));
// setup timer to send data at a given interval
mSendTimer = new QTimer(this);
connect(mSendTimer, SIGNAL(timeout()),
this, SLOT(sendSlot()));
mSendTimer->start(40);
}
void Server::sendSlot()
{
if(!mTcpSocket)
return;
//know that the image is this big
int width = 800;
int height = 600;
int nChannels = 3;
int depth = 8;
qint64 blockSize = 1440000; //in bytes
qint64 imagesInQue = mTcpSocket->bytesToWrite()/blockSize;
int maxPendingImages = 25;
if(imagesInQue > maxPendingImages)
{
std::cout << "Dumping." << std::endl;
return;
}
//load image
IplImage* img = cvLoadImage("pic1_24bit.bmp");
if(!img)
std::cout << "Error loading image " << std::endl;;
//send data
quint64 written = mTcpSocket->write(img->imageData, img->imageSize);
//clean up
cvReleaseImage( &img );
}
客户：
主文件
#include <iostream>
#include <QCoreApplication>
#include "Client.h"
int main(int argc, char *argv[]){
QCoreApplication app(argc, argv);
QString ipaddress = QString(argv[1]);
int port = atoi(argv[2]);
Client* client = new Client(ipaddress, port);
int retVal = app.exec();
}
客户端.h
#ifndef CLIENT_H_
#define CLIENT_H_
#include <QObject>
#include <QAbstractSocket>
QT_BEGIN_NAMESPACE
class QTcpSocket;
QT_END_NAMESPACE
class Client : public QObject
{
Q_OBJECT
public:
Client(QString ipAddress, int port, QObject *parent=0);
private slots:
void readSlot();
void displayErrorSlot(QAbstractSocket::SocketError);
private:
QTcpSocket *mTcpSocket;
QString mIpAddress;
int mPort;
};
#endif /* CLIENT_H_ */
客户端.cpp
#include "Client.h"
#include <iostream>
#include <QTcpSocket>
#include <QSettings>
#include <QDateTime>
Client::Client(QString ipAddress, int port, QObject *parent):
QObject(parent), mTcpSocket(0), mIpAddress(ipAddress), mPort(port)
{
mTcpSocket = new QTcpSocket(this);
connect(mTcpSocket, SIGNAL(readyRead()),
this, SLOT(readSlot()));
connect(mTcpSocket, SIGNAL(error(QAbstractSocket::SocketError)),
this, SLOT(displayErrorSlot(QAbstractSocket::SocketError)));
std::cout << "Connecting to ip: " << mIpAddress.toStdString() << " port: " << mPort << std::endl;
mTcpSocket->connectToHost(mIpAddress, mPort);
}
void Client::readSlot()
{
static qint64 starttime = QDateTime::currentMSecsSinceEpoch();
static int frames = 0;
//know that the image is this big
int width = 800;
int height = 600;
int nChannels = 3;
int depth = 8;
qint64 blockSize = 1440000; //in bytes
if (mTcpSocket->bytesAvailable() < blockSize)
{
return;
}
frames++;
char* data = (char*) malloc(blockSize+100);
qint64 bytesRead = mTcpSocket->read(data, blockSize);
free(data);
//FPS
if(frames % 100 == 0){
float fps = frames/(QDateTime::currentMSecsSinceEpoch() - starttime);
std::cout << "FPS: " << fps << std::endl;
}
}
void Client::displayErrorSlot(QAbstractSocket::SocketError socketError)
{
switch (socketError) {
case QAbstractSocket::RemoteHostClosedError:
break;
case QAbstractSocket::HostNotFoundError:
std::cout << "The host was not found. Please check the "
"host name and port settings."<< std::endl;
break;
case QAbstractSocket::ConnectionRefusedError:
std::cout << "The connection was refused by the peer. "
"Make sure the fortune server is running, "
"and check that the host name and port "
"settings are correct."<< std::endl;
break;
default:
std::cout << "The following error occurred: " << mTcpSocket->errorString().toStdString() << std::endl;
break;
}
}