WebRTC学习之十：最简单的视频聊天（使用WebRtcVideoEngine2）
这篇在上篇WebRTC学习之九：摄像头的捕捉和显示 的基础上修改而来。上篇中主要使用了WebRtcVideoEngine2中的WebRtcVideoCapturer类，而本篇中主要使用了WebRtcVideoEngine2中的WebRtcVideoChannel2类。
一.环境
参考：WebRTC学习之三：录音和播放
二.实现
在WebRTC学习之四：最简单的语音聊天 中我们是通过实现Transport类的两个纯虚函数SendRtp和SendRtcp，并在它们的实现中调用通信协议的发送函数将数据发送出去。然而WebRtcVideoChannel2类继承自Transport，实现了SendRtp和SendRtcp，并在实现中分别调用了MediaChannel类的SendPacket和SendRtcp函数。MediaChannel类也是WebRtcVideoChannel2的基类。SendPacket和SendRtcp函数最终调用的是MediaChannel类中NetworkInterface接口的同名函数SendPacket和SendRtcp。因此我们只需要去继承NetworkInterface接口，实现其中的函数SendPacket和SendRtcp，并在它们的实现中调用通信协议的发送函数将数据发送出去。
mynetworkinterface.h
#ifndef MYNETWORKINTERFACE_H
#define MYNETWORKINTERFACE_H
#include
#include "webrtc/media/base/mediachannel.h"
#include "webrtc/modules/rtp_rtcp/source/byte_io.h"
class MyNetworkInterface:public QObject,public cricket::MediaChannel::NetworkInterface
{
Q_OBJECT
public:
MyNetworkInterface();
~MyNetworkInterface();
void setLocalReceiver(int port);
void stopRecieve();
void setSendDestination(QString ip, int port);
void stopSend();
// NetworkInterface functions override
bool SendPacket(rtc::CopyOnWriteBuffer* packet,const rtc::PacketOptions& options) override;
bool SendRtcp(rtc::CopyOnWriteBuffer* packet,const rtc::PacketOptions& options) override;
int SetOption(SocketType type, rtc::Socket::Option opt,int option) override
{
return 0;
}
private:
QUdpSocket * udpsocketSendRTP;
QUdpSocket * udpsocketSendRTCP;
QUdpSocket * udpSocketRecvRTP;
QUdpSocket * udpSocketRecvRTCP;
QString destIP;
int destPort;
bool sendFlag;
bool recvFlag;
signals:
void signalRecvRTPData(char *data,int length);
void signalRecvRTCPData(char *data,int length);
void signalSendRTPData(char *data,int length);
void signalSendRTCPData(char *data,int length);
private slots:
void slotRTPReadPendingDatagrams();
void slotRTCPReadPendingDatagrams();
void slotSendRTPData(char *data,int length);
void slotSendRTCPData(char *data,int length);
};
#endif // MYNETWORKINTERFACE_H mynetworkinterface.cpp
#include "mynetworkinterface.h"
#include "QDebug"
#include
MyNetworkInterface::MyNetworkInterface()
:destIP(""),
destPort(0),
sendFlag(true),
recvFlag(true)
{
udpsocketSendRTP=new QUdpSocket();
udpSocketRecvRTP = new QUdpSocket();
udpsocketSendRTCP=new QUdpSocket();
udpSocketRecvRTCP = new QUdpSocket();
connect(udpSocketRecvRTP, SIGNAL(readyRead()), this, SLOT(slotRTPReadPendingDatagrams()));
connect(udpSocketRecvRTCP, SIGNAL(readyRead()), this, SLOT(slotRTCPReadPendingDatagrams()));
connect(this,SIGNAL(signalSendRTPData(char *,int)),this,SLOT(slotSendRTPData(char *,int)));
connect(this,SIGNAL(signalSendRTCPData(char *,int)),this,SLOT(slotSendRTCPData(char *,int)));
}
MyNetworkInterface::~MyNetworkInterface()
{
udpsocketSendRTP->deleteLater();
udpSocketRecvRTP->deleteLater();
udpsocketSendRTCP->deleteLater();
udpSocketRecvRTCP->deleteLater();
}
void MyNetworkInterface::setLocalReceiver(int port)
{
udpSocketRecvRTP->bind(port, QUdpSocket::ShareAddress);
udpSocketRecvRTCP->bind(port+1, QUdpSocket::ShareAddress);
recvFlag=true;
}
void MyNetworkInterface::stopRecieve()
{
udpSocketRecvRTP->abort();
udpSocketRecvRTCP->abort();
recvFlag=false;
}
void MyNetworkInterface::setSendDestination(QString ip, int port)
{
destIP=ip;
destPort=port;
sendFlag=true;
}
void MyNetworkInterface::stopSend()
{
sendFlag=false;
}
//为何不直接调用udpsocketSendRTP->writeDatagram，而用信号，是因为SendPacket在另一个线程里
bool MyNetworkInterface::SendPacket(rtc::CopyOnWriteBuffer* packet,const rtc::PacketOptions& options)
{
Q_UNUSED(options);
//测试发送的ssrc
// uint8_t* packet1=(uint8_t*)data;
// uint32_t ssrc = webrtc::ByteReader::ReadBigEndian(&packet1[8]);
// qDebug()<<"Send SSRC:"<data(),packet->size());
return true;
}
//为何不直接调用udpsocketSendRTCP->writeDatagram，而用信号，是因为SendRtcp在另一个线程里
bool MyNetworkInterface::SendRtcp(rtc::CopyOnWriteBuffer* packet,const rtc::PacketOptions& options)
{
Q_UNUSED(options);
if(sendFlag)
emit signalSendRTCPData(packet->data(),packet->size());
return true;
}
void MyNetworkInterface::slotSendRTPData(char *data,int length)
{
//测试发送的ssrc
// uint8_t* packet1=(uint8_t*)data;
// uint32_t ssrc = webrtc::ByteReader::ReadBigEndian(&packet1[8]);
// qDebug()<<"Send SSRC:"<writeDatagram(data, length,QHostAddress(destIP), destPort);
}
//RTCP端口为RTP端口+1
void MyNetworkInterface::slotSendRTCPData(char *data,int length)
{
udpsocketSendRTCP->writeDatagram(data, length,QHostAddress(destIP), destPort+1);
}
void MyNetworkInterface::slotRTPReadPendingDatagrams()
{
QByteArray datagram;
while (udpSocketRecvRTP->hasPendingDatagrams()&&recvFlag)
{
datagram.resize(udpSocketRecvRTP->pendingDatagramSize());
QHostAddress sender;
quint16 senderPort;
int size=udpSocketRecvRTP->readDatagram(
datagram.data(),
datagram.size(),
&sender,
&senderPort);
if(size>0)
{
//测试接收的ssrc
// uint8_t* packet1=(uint8_t*)data;
// uint32_t ssrc = webrtc::ByteReader::ReadBigEndian(&packet1[8]);
// qDebug()<<"Receive SSRC:"<hasPendingDatagrams()&&recvFlag)
{
datagram.resize(udpSocketRecvRTCP->pendingDatagramSize());
QHostAddress sender;
quint16 senderPort;
int size=udpSocketRecvRTCP->readDatagram(
datagram.data(),
datagram.size(),
&sender,
&senderPort);
if(size>0)
{
emit signalRecvRTCPData(datagram.data(),datagram.size());
}
}
} WebRtcVideoChannel2中有个专门设置网络接口的函数SetInterface，其参数就是NetworkInterface，这样视频数据发送就与WebRtcVideoChannel2关联起来了。
至于频数据接收，需要调用通信协议的接收函数，将接收到的数据传递到WebRtcVideoChannel2的OnPacketReceived和OnRtcpReceived函数，这两个函数是其基类对应纯虚函数的实现。那么解码后的frame我们如何获取呢？在WebRtcVideoChannel2中有个函数SetSink，它的第二个参数是rtc::VideoSinkInterface
void MainWindow::OnFrame(const cricket::VideoFrame& frame)
{
//复制一份
const cricket::VideoFrame* frameTemp = frame.GetCopyWithRotationApplied();
frameTemp->ConvertToRgbBuffer(cricket::FOURCC_ARGB,
receivedVideoImageData.get(),
frameTemp->width()*frameTemp->height()*32/8,
frameTemp->width()*32/8);
QImage image(receivedVideoImageData.get(), frameTemp->width(), frameTemp->height(), QImage::Format_RGB32);
//因为OnFrame在另一个线程，所以不直接显示，用信号中转一下,将显示放在GUI线程（主线程）
if(!image.isNull())
emit signalReceivedFrame(image);
}
void MainWindow::slotReceivedFrame(const QImage &image)
{
ui->labelReceivedVideo->setPixmap(QPixmap::fromImage(image));
}
本人光荣上镜，长相一般，用个口罩挡一下。大窗口是摄像头捕捉和显示的图像，小窗口是通过网络接收到并显示的图像。
