WebRTC C++ peerconnection client例子

准备

简单

两台带有麦克风和摄像头的电脑

复杂

没有麦克风和摄像头的单台电脑需要安装OBS软件（虚拟摄像头）

代码方面需要禁用音频

void Conductor::AddTracks() {
  if (!peer_connection_->GetSenders().empty()) {
    return;  // Already added tracks.
  }

//   rtc::scoped_refptr<webrtc::AudioTrackInterface> audio_track(
//       peer_connection_factory_->CreateAudioTrack(
//           kAudioLabel,
//           peer_connection_factory_->CreateAudioSource(cricket::AudioOptions())
//               .get()));
//   auto result_or_error = peer_connection_->AddTrack(audio_track, {kStreamId});
//   if (!result_or_error.ok()) {
//     RTC_LOG(LS_ERROR) << "Failed to add audio track to PeerConnection: "
//                       << result_or_error.error().message();
//   }

  rtc::scoped_refptr<CapturerTrackSource> video_device =
      CapturerTrackSource::Create();
  if (video_device) {
    rtc::scoped_refptr<webrtc::VideoTrackInterface> video_track_(
        peer_connection_factory_->CreateVideoTrack(video_device, kVideoLabel));
    main_wnd_->StartLocalRenderer(video_track_.get());

   auto result_or_error =
        peer_connection_->AddTrack(video_track_, {kStreamId});
    if (!result_or_error.ok()) {
      RTC_LOG(LS_ERROR) << "Failed to add video track to PeerConnection: "
                        << result_or_error.error().message();
    }
  } else {
    RTC_LOG(LS_ERROR) << "OpenVideoCaptureDevice failed";
  }

  main_wnd_->SwitchToStreamingUI();
}

OBS版本：OBS-Studio-29.1.3-Full-Installer-x64.exe

配置参考

手把手！教你用新版OBS虚拟摄像头 - 哔哩哔哩 (bilibili.com)

可以使用自动配置向导，选择最后一项“我只使用虚拟摄像机”即可

回到主界面，在下方的“来源”栏下点击“+”加号，添加一个“媒体源”  

点击“浏览”，选择刚才录制好的视频文件  

选择好文件后，一定记得勾选“循环”！  

单击主界面右下角“控件”一栏里的“启动虚拟摄像机”

WebRTC服务器配置

src\examples\peerconnection\client\flag_defs.h

ABSL_FLAG(std::string, server, "localhost", "The server to connect to.");

定义了连接WebRTC服务器IP地址

修改为指定的服务器IP地址

src\examples\peerconnection\client\defaults.cc

const uint16_t kDefaultServerPort = 8888;

定义了连接WebRTC服务器端口

操作

任意一方可以在中途按ESC键退出音视频通信

运行失败按照如下修改代码

依次运行exe文件peerconnection_server和peerconnection_client，可以发现server窗口中出现了新的连接字样，但是client并没有跳转画面，依旧卡在初始界面

方法一

运行PeerConnectionClient，使用本地ip连接PeerConnectionServer时，PeerConnectionClient的onConnect没有回调。经过分析，是由于main.cc定义的线程没有运行

需要在peer_connection_client.cc中的方法PeerConnectionClient::DoConnect()添加逻辑，在方法最后添加rtc::Thread::Current()->Start();

void PeerConnectionClient::DoConnect() {
  control_socket_.reset(CreateClientSocket(server_address_.ipaddr().family()));
  hanging_get_.reset(CreateClientSocket(server_address_.ipaddr().family()));
  InitSocketSignals();
  char buffer[1024];
  snprintf(buffer, sizeof(buffer), "GET /sign_in?%s HTTP/1.0\r\n\r\n",
           client_name_.c_str());
  onconnect_data_ = buffer;

  bool ret = ConnectControlSocket();
  if (ret)
    state_ = SIGNING_IN;
  if (!ret) {
    callback_->OnServerConnectionFailure();
  }
  rtc::Thread::Current()->Start();
}

另外还有个线程死等的问题，要修改peer_connection_client.cc中的Wait方法

windows运行webrtc的PeerConnectionClient连接问题修复_peerconnectionclient 空白_vsix_ling的博客-CSDN博客

方法二

/*
 *  Copyright 2012 The WebRTC Project Authors. All rights reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

// clang-format off
// clang formating would change include order.
#include <windows.h>
#include <shellapi.h>  // must come after windows.h
// clang-format on

#include <string>
#include <vector>

#include "absl/flags/parse.h"
#include "examples/peerconnection/client/conductor.h"
#include "examples/peerconnection/client/flag_defs.h"
#include "examples/peerconnection/client/main_wnd.h"
#include "examples/peerconnection/client/peer_connection_client.h"
#include "rtc_base/checks.h"
#include "rtc_base/ssl_adapter.h"
#include "rtc_base/string_utils.h"  // For ToUtf8
#include "rtc_base/win32_socket_init.h"
#include "system_wrappers/include/field_trial.h"
#include "test/field_trial.h"


 #include "rtc_base/logging.h"
 #include "rtc_base/log_sinks.h"

namespace  {
// A helper class to translate Windows command line arguments into UTF8,
// which then allows us to just pass them to the flags system.
// This encapsulates all the work of getting the command line and translating
// it to an array of 8-bit strings; all you have to do is create one of these,
// and then call argc() and argv().
class WindowsCommandLineArguments {
 public:
  WindowsCommandLineArguments();

  WindowsCommandLineArguments(const WindowsCommandLineArguments&) = delete;
  WindowsCommandLineArguments& operator=(WindowsCommandLineArguments&) = delete;

  int argc() { return argv_.size(); }
  char** argv() { return argv_.data(); }

 private:
  // Owned argument strings.
  std::vector<std::string> args_;
  // Pointers, to get layout compatible with char** argv.
  std::vector<char*> argv_;
};

WindowsCommandLineArguments::WindowsCommandLineArguments() {
  // start by getting the command line.
  LPCWSTR command_line = ::GetCommandLineW();
  // now, convert it to a list of wide char strings.
  int argc;
  LPWSTR* wide_argv = ::CommandLineToArgvW(command_line, &argc);

  // iterate over the returned wide strings;
  for (int i = 0; i < argc; ++i) {
    args_.push_back(rtc::ToUtf8(wide_argv[i], wcslen(wide_argv[i])));
    // make sure the argv array points to the string data.
    argv_.push_back(const_cast<char*>(args_.back().c_str()));
  }
  LocalFree(wide_argv);
}

}  // namespace

class CustomSocketServer : public rtc::PhysicalSocketServer {
 public:
  bool Wait(webrtc::TimeDelta max_wait_duration, bool process_io) override {
    if (!process_io)
      return true;
    return rtc::PhysicalSocketServer::Wait(webrtc::TimeDelta::Zero(),
                                           process_io);
  }
};

int PASCAL wWinMain(HINSTANCE instance,
                    HINSTANCE prev_instance,
                    wchar_t* cmd_line,
                    int cmd_show) {
  rtc::WinsockInitializer winsock_init;
  //rtc::PhysicalSocketServer ss;
  CustomSocketServer ss;
  rtc::AutoSocketServerThread main_thread(&ss);

  rtc::FileRotatingLogSink* pLog = new rtc::FileRotatingLogSink("D:/", "webrtc.log", 1024*1024*10, 10);
  pLog->Init();
  rtc::LogMessage::AddLogToStream(pLog, rtc::LS_VERBOSE);

  WindowsCommandLineArguments win_args;
  int argc = win_args.argc();
  char** argv = win_args.argv();

  absl::ParseCommandLine(argc, argv);

  // InitFieldTrialsFromString stores the char*, so the char array must outlive
  // the application.
  const std::string forced_field_trials =
      absl::GetFlag(FLAGS_force_fieldtrials);
  webrtc::field_trial::InitFieldTrialsFromString(forced_field_trials.c_str());

  // Abort if the user specifies a port that is outside the allowed
  // range [1, 65535].
  if ((absl::GetFlag(FLAGS_port) < 1) || (absl::GetFlag(FLAGS_port) > 65535)) {
    printf("Error: %i is not a valid port.\n", absl::GetFlag(FLAGS_port));
    return -1;
  }

  const std::string server = absl::GetFlag(FLAGS_server);
  MainWnd wnd(server.c_str(), absl::GetFlag(FLAGS_port),
              absl::GetFlag(FLAGS_autoconnect), absl::GetFlag(FLAGS_autocall));
  if (!wnd.Create()) {
    RTC_DCHECK_NOTREACHED();
    return -1;
  }

  rtc::InitializeSSL();
  PeerConnectionClient client;
  auto conductor = rtc::make_ref_counted<Conductor>(&client, &wnd);
  main_thread.Start();
  // Main loop.
  MSG msg;
  BOOL gm;
  while ((gm = ::GetMessage(&msg, NULL, 0, 0)) != 0 && gm != -1) {
    if (!wnd.PreTranslateMessage(&msg)) {
      ::TranslateMessage(&msg);
      ::DispatchMessage(&msg);
    }
  }

  if (conductor->connection_active() || client.is_connected()) {
    while ((conductor->connection_active() || client.is_connected()) &&
           (gm = ::GetMessage(&msg, NULL, 0, 0)) != 0 && gm != -1) {
      if (!wnd.PreTranslateMessage(&msg)) {
        ::TranslateMessage(&msg);
        ::DispatchMessage(&msg);
      }
    }
  }

  rtc::CleanupSSL();
  return 0;
}

注意事项

默认启动后是 localhost ，不知道为什么我必须改成 127.0.0.1 才可以连接服务器成功。 翻阅资料得出结果是因为 windows 把 localhost 解析为 ipv6 地址 ::1 而不是 127.0.0.1。查了hosts 把ipv6已经屏蔽了，127.0.0.1 localhost 也有，就是不能正常解析

退出崩溃解决

去掉RTC_NORETURN提示错误

function declared 'noreturn' should not return [-Werror,-Winvalid-noreturn]

修改代码如下

RTC_NORETURN void WriteFatalLog(absl::string_view output) {
#if defined(WEBRTC_ANDROID)
  std::string output_str(output);
  __android_log_print(ANDROID_LOG_ERROR, RTC_LOG_TAG_ANDROID, "%s\n",
                      output_str.c_str());
#endif
   fflush(stdout);
   fwrite(output.data(), output.size(), 1, stderr);
   fflush(stderr);
#if defined(WEBRTC_WIN)
  //DebugBreak();
#endif
  exit(0);
  //abort();
}

外网扩展

Windows下 WebRTC Demo运行： PeerConnection_window.rtcpeerconnection文档_chenxiemin的博客-CSDN博客

参考

fix.patch (1.2 KB) - webrtc - Web-based real-time communication - Monorail (chromium.org)

13498 - the peerconnection_client on windows not displaying the video on win10 - webrtc (chromium.org)

【Bug修复记录】WebRTC源码demo无法运行_陈成不姓丞的博客-CSDN博客