标签:for 图像 pos ase 版本 creat win support 异步
上图中base文件夹中是一些抽象类。engine文件夹中是相应抽象类的实现,使用时直接调用engine文件夹中的接口就可以。WebRtcVoiceEngine实际上是VoiceEngine的再次封装。它使用VoiceEngine进行音频处理。
注意命名,WebRtcVideoEngine2带了个2字,不用想,这肯定是个升级版本号的VideoEngine,还有个WebRtcVideoEngine类。
WebRtcVideoEngine2比WebRtcVideoEngine改进之处在于将视频流一分为二:发送流(WebRtcVideoSendStream)和接收流(WebRtcVideoReceiveStream),从而结构上更合理。源代码更清晰。
本文的实现主要是使用了WebRtcVideoEngine2中WebRtcVideoCapturer类。
一.环境
參考上篇:WebRTC学习之三:录音和播放
二.实现
打开WebRtcVideoCapturer的头文件webrtcvideocapture.h。公有的函数基本上都是base文件夹中VideoCapturer类的实现,用于初始化设备和启动捕捉。私有函数OnIncomingCapturedFrame和OnCaptureDelayChanged会在摄像头採集模块VideoCaptureModeule中回调。将採集的图像传给OnIncomingCapturedFrame,并将採集的延时变化传给OnCaptureDelayChanged。
WebRTC中也实现了类似Qt中的信号和槽机制,详见WebRTC学习之七:精炼的信号和槽机制 。可是就像在该文中提到的,sigslot.h中的emit函数名会和Qt中的emit宏冲突。我将sigslot.h中的emit改成了Emit,当然改完之后,须要又一次编译rtc_baseproject。
VideoCapturer类有两个信号sigslot::signal2<VideoCapturer*, CaptureState> SignalStateChange和sigslot::signal2<VideoCapturer*, const CapturedFrame*, sigslot::multi_threaded_local> SignalFrameCaptured,从SignalFrameCaptured的參数能够看出我们仅仅要实现相应的槽函数就能获取到CapturedFrame,在槽函数中将
CapturedFrame进行转换显示就可以。SignalStateChange信号的參数CaptureState是个枚举。标识捕捉的状态(停止、開始、正在进行、失败)。
信号SignalFrameCaptured正是在回调函数OnIncomingCapturedFrame中发射出去的。
OnIncomingCapturedFrame里面用到了函数的异步运行。详见WebRTC学习之八:函数的异步运行。
mainwindow.h
#ifndef MAINWINDOW_H #define MAINWINDOW_H #include <QMainWindow> #include <QDebug> #include <map> #include <memory> #include <string> #include "webrtc/base/sigslot.h" #include "webrtc/modules/video_capture/video_capture.h" #include "webrtc/modules/video_capture/video_capture_factory.h" #include "webrtc/media/base/videocapturer.h" #include "webrtc/media/engine/webrtcvideocapturer.h" #include "webrtc/media/engine/webrtcvideoframe.h" namespace Ui { class MainWindow; } class MainWindow : public QMainWindow,public sigslot::has_slots<> { Q_OBJECT public: explicit MainWindow(QWidget *parent = 0); ~MainWindow(); void OnFrameCaptured(cricket::VideoCapturer* capturer, const cricket::CapturedFrame* frame); void OnStateChange(cricket::VideoCapturer* capturer, cricket::CaptureState state); private slots: void on_pushButtonOpen_clicked(); private: void getDeviceList(); private: Ui::MainWindow *ui; cricket::WebRtcVideoCapturer *videoCapturer; cricket::WebRtcVideoFrame *videoFrame; std::unique_ptr<uint8_t[]> videoImage; QStringList deviceNameList; QStringList deviceIDList; }; #endif // MAINWINDOW_Hmainwindow.cpp
#include "mainwindow.h" #include "ui_mainwindow.h" MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow), videoCapturer(new cricket::WebRtcVideoCapturer()), videoFrame(new cricket::WebRtcVideoFrame()) { ui->setupUi(this); getDeviceList(); } MainWindow::~MainWindow() { delete ui; videoCapturer->SignalFrameCaptured.disconnect(this); videoCapturer->SignalStateChange.disconnect(this); videoCapturer->Stop(); } void MainWindow::OnFrameCaptured(cricket::VideoCapturer* capturer,const cricket::CapturedFrame* frame) { videoFrame->Init(frame, frame->width, frame->height,true); //将视频图像转成RGB格式 videoFrame->ConvertToRgbBuffer(cricket::FOURCC_ARGB, videoImage.get(), videoFrame->width()*videoFrame->height()*32/8, videoFrame->width()*32/8); QImage image(videoImage.get(), videoFrame->width(), videoFrame->height(), QImage::Format_RGB32); ui->label->setPixmap(QPixmap::fromImage(image)); } void MainWindow::OnStateChange(cricket::VideoCapturer* capturer, cricket::CaptureState state) { } void MainWindow::getDeviceList() { deviceNameList.clear(); deviceIDList.clear(); webrtc::VideoCaptureModule::DeviceInfo *info=webrtc::VideoCaptureFactory::CreateDeviceInfo(0); int deviceNum=info->NumberOfDevices(); for (int i = 0; i < deviceNum; ++i) { const uint32_t kSize = 256; char name[kSize] = {0}; char id[kSize] = {0}; if (info->GetDeviceName(i, name, kSize, id, kSize) != -1) { deviceNameList.append(QString(name)); deviceIDList.append(QString(id)); ui->comboBoxDeviceList->addItem(QString(name)); } } if(deviceNum==0) { ui->pushButtonOpen->setEnabled(false); } } void MainWindow::on_pushButtonOpen_clicked() { static bool flag=true; if(flag) { ui->pushButtonOpen->setText(QStringLiteral("关闭")); const std::string kDeviceName = ui->comboBoxDeviceList->currentText().toStdString(); const std::string kDeviceId = deviceIDList.at(ui->comboBoxDeviceList->currentIndex()).toStdString(); videoCapturer->Init(cricket::Device(kDeviceName, kDeviceId)); int width=videoCapturer->GetSupportedFormats()->at(0).width; int height=videoCapturer->GetSupportedFormats()->at(0).height; cricket::VideoFormat format(videoCapturer->GetSupportedFormats()->at(0)); //開始捕捉 if(cricket::CS_STARTING == videoCapturer->Start(format)) { qDebug()<<"Capture is started"; } //连接WebRTC的信号和槽 videoCapturer->SignalFrameCaptured.connect(this,&MainWindow::OnFrameCaptured); videoCapturer->SignalStateChange.connect(this,&MainWindow::OnStateChange); if(videoCapturer->IsRunning()) { qDebug()<<"Capture is running"; } videoImage.reset(new uint8_t[width*height*32/8]); } else { ui->pushButtonOpen->setText(QStringLiteral("打开")); //反复连接会报错,须要先断开,才干再次连接 videoCapturer->SignalFrameCaptured.disconnect(this); videoCapturer->SignalStateChange.disconnect(this); videoCapturer->Stop(); if(!videoCapturer->IsRunning()) { qDebug()<<"Capture is stoped"; } ui->label->clear(); } flag=!flag; }main.cpp
#include "mainwindow.h" #include <QApplication> int main(int argc, char *argv[]) { QApplication a(argc, argv); MainWindow w; w.show(); while(true) { //WebRTC消息循环 rtc::Thread::Current()->ProcessMessages(0); rtc::Thread::Current()->SleepMs(1); //Qt消息循环 a.processEvents( ); } }注意main函数中对WebRTC和Qt消息循环的处理,这是用Qt调用WebRTC进行摄像头捕捉和显示的关键。
三.效果
标签:for 图像 pos ase 版本 creat win support 异步
原文地址:http://www.cnblogs.com/gccbuaa/p/7354348.html