Qt音视频开发46-视频传输UDP版

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四、相关站点

1. 国内站点：https://gitee.com/feiyangqingyun/QWidgetDemo
2. 国际站点：https://github.com/feiyangqingyun/QWidgetDemo
3. 个人主页：https://blog.csdn.net/feiyangqingyun
4. 知乎主页：https://www.zhihu.com/people/feiyangqingyun/
5. 体验地址：https://blog.csdn.net/feiyangqingyun/article/details/97565652

五、核心代码

#include "udpimageclient.h"
#include "devicefun.h"

QScopedPointer<UdpImageClient> UdpImageClient::self;
UdpImageClient *UdpImageClient::Instance()
{
    if (self.isNull()) {
        static QMutex mutex;
        QMutexLocker locker(&mutex);
        if (self.isNull()) {
            self.reset(new UdpImageClient);
        }
    }

    return self.data();
}

UdpImageClient::UdpImageClient(QObject *parent) : QThread(parent)
{
    //如果是外网请自行调整这个值的大小,外网需要调小
    packageSize = 10000;
    flag = "SHJC00000001";
    serverIP = "127.0.0.1";
    serverPort = 6000;

    stopped = false;

    //UDP通信对象
    udpSocket = new QUdpSocket(this);
    connect(udpSocket, SIGNAL(readyRead()), this, SLOT(readData()));

    //定时器解析收到的数据,可以自行调整间隔
    timerData = new QTimer(this);
    connect(timerData, SIGNAL(timeout()), this, SLOT(checkData()));
    timerData->setInterval(100);

    //绑定信号启动后启动定时器
    connect(this, SIGNAL(started()), this, SLOT(started()));
    //绑定发送数据信号槽
    connect(this, SIGNAL(readyWrite(QString)), this, SLOT(sendImage(QString)));
}

UdpImageClient::~UdpImageClient()
{
    this->stop();
}

void UdpImageClient::run()
{
    while (!stopped) {
        //这里采用线程去处理,其实完全可以用定时器搞定,毕竟tcp的write是异步的,操作系统自动调度
        //为了后期的拓展性,比如需要判断是否发送成功之类的,需要同步处理,所以改成的线程去处理
        //图片数据转成base64编码的数据也需要时间的,主要的耗时在转码
        //取出数据发送,这里需要加锁,避免正在插入数据
        if (images.count() > 0) {
            QMutexLocker locker(&mutexImage);
            QImage image = images.takeFirst();
            QString imageData = DeviceFun::getImageData(image);
            emit readyWrite(imageData);
        }

        //要稍微休息下,否则CPU会被一直占用
        msleep(1);
    }

    stopped = false;
}

void UdpImageClient::readData()
{
    QHostAddress host;
    quint16 port;
    QByteArray data;

    while (udpSocket->hasPendingDatagrams()) {
        data.resize(udpSocket->pendingDatagramSize());
        udpSocket->readDatagram(data.data(), data.size(), &host, &port);

        //接收的数据存入buffer需要加锁
        QMutexLocker locker(&mutexData);
        buffer.append(data);
        emit receiveData(data);
    }
}

void UdpImageClient::checkData()
{
    if (buffer.length() == 0) {
        return;
    }

    //取出数据处理需要加锁,防止此时正在插入数据
    QMutexLocker locker(&mutexData);
    QDomDocument dom;
    if (!DeviceFun::getReceiveXmlData(buffer, dom, "IIMAGE:", 11, true)) {
        return;
    }

    //逐个取出节点判断数据
    QDomElement element = dom.documentElement();
    if (element.tagName() == "ImageServer") {
        QString uuid = element.attribute("Uuid");
        QDomNode childNode = element.firstChild();
        QString name = childNode.nodeName();
        QString value = element.text();
        //qDebug() << uuid << name << value;
        //这里可以根据收到的数据自行增加自己的处理
    }
}

void UdpImageClient::started()
{
    if (!timerData->isActive()) {
        timerData->start();
    }
}

void UdpImageClient::stop()
{
    buffer.clear();
    images.clear();
    stopped = true;
    this->wait();
    udpSocket->disconnectFromHost();

    if (timerData->isActive()) {
        timerData->stop();
    }
}

void UdpImageClient::setPackageSize(int packageSize)
{
    if (packageSize <= 65507) {
        this->packageSize = packageSize;
    }
}

void UdpImageClient::setFlag(const QString &flag)
{
    this->flag = flag;
}

void UdpImageClient::setServerIP(const QString &serverIP)
{
    this->serverIP = serverIP;
}

void UdpImageClient::setServerPort(int serverPort)
{
    this->serverPort = serverPort;
}

void UdpImageClient::writeData(const QString &body)
{
    //构建xml字符串
    QStringList list;
    list.append(QString("<ImageClient Uuid=\"%1\" Flag=\"%2\">").arg(DeviceFun::getUuid()).arg(flag));
    list.append(body);
    list.append("</ImageClient>");

    //调用通用方法根据协议组成完整数据
    QString data = DeviceFun::getSendXmlData(list.join(""), "IIMAGE:");
    QByteArray buffer = data.toUtf8();

    //udp最大只能发送65507字节的数据=64K 超过的话都会发送失败
    //所以这里需要手动分包,外网的话包还要小一点
    if (packageSize == 65500) {
        udpSocket->writeDatagram(buffer, QHostAddress(serverIP), serverPort);
    } else {
        int len = buffer.length();
        int count = len / packageSize + 1;
        for (int i = 0; i < count; i++) {
            QByteArray temp = buffer.mid(i * packageSize, packageSize);
            udpSocket->writeDatagram(temp, QHostAddress(serverIP), serverPort);
        }
    }

    emit sendData(buffer);
}

void UdpImageClient::sendImage(const QString &body)
{
    writeData(QString("<ClientImage>%1</ClientImage>").arg(body));
}

void UdpImageClient::append(const QImage &image)
{
    //这里需要加锁,避免正在取出数据
    QMutexLocker locker(&mutexImage);
    //限制队列中最大消息数,避免离线的时候疯狂插入
    if (this->isRunning() && images.count() < 10) {
        images << image;
    }
}

void UdpImageClient::clear()
{
    QMutexLocker locker(&mutexImage);
    images.clear();
}