Start a Video Call

Use this guide to quickly start a basic video call with the Agora Video SDK for Windows.

Understand the tech

The following figure shows the workflow to integrate into your app in order to add Video Call functionality.

As shown in the figure, the workflow for adding Video Call in your project is as follows:

1. Retrieve a token
   A token is the credential that authenticates a user when your app client joins a channel. In a test or production environment, your app client retrieves tokens from a server in your security infrastructure.

2. Join a channel
   Call joinChannel to create and join a channel. App clients that pass the same channel name join the same channel.

3. Publish and subscribe to audio and video in the channel
   After joining a channel, the app client automatically publishes and subscribes to audio and video in the channel.

For an app client to join a channel, you need the following information:

• The App ID: A randomly generated string provided by Agora for identifying your app. You can get the App ID from Agora Console.
• The user ID: The unique identifier of a user. You need to specify the user ID yourself, and ensure that it is unique in the channel.
• A token: In a test or production environment, your app client retrieves tokens from a server in your security infrastructure. For this page, you use a temporary token with a validity period of 24 hours that you retrieve from Agora Console.
• The channel name: A string that identifies the channel for the video call.

Sample projects

We provide the open-source sample projects that implement the video call on GitHub:

• Agora-Windows-Tutorial-1to1
• GroupVideoCall-Windows-MFC

Before implementing a video call, you can download the sample projects and refer to the source code.

Prerequisites

• Microsoft Visual Studio 2017 or later
• A Windows device running Windows 7 or later
• A valid Agora account. (Sign up for free)

Set up the development environment

In this section, we will create a Windows project and integrate the SDK into the project.

Create a Windows project

Now, let's build a Windows project from scratch. Skip to Integrate the SDK if a Windows project already exists.

Integrate the SDK

Follow these steps to integrate the Agora Video SDK into your project.

1. Configure the project files

• Go to SDK Downloads, download the latest version of the Agora SDK for Windows, and unzip the downloaded SDK package.
• Copy the x86 or x86_64 folder of the downloaded SDK package to your project files according to your development environment.

2. Configure the project properties

Right-click the project name in the Solution Explorer window, click Properties to configure the following project properties, and click OK.

• Go to the C/C++ > General > Additional Include Directories menu, click Edit, and input $(SolutionDir)include in the pop-up window.
• Go to the Linker > General > Additional Library Directories menu, click Edit, and input $(SolutionDir) in the pop-up window.
• Go to the Linker > Input > Additional Dependencies menu, click Edit, and input agora_rtc_sdk.lib in the pop-up window.

Implement the basic call

This section introduces how to use the Agora SDK to make a video call. The following figure shows the API call sequence of a basic one-to-one video call.

1. Create the UI

Create the user interface (UI) for the one-to-one video call in your project. Skip to Initialize IRtcEngine if you already have a UI in your project.

If you are implementing a video call, we recommend adding the following elements into the UI:

• The local video view
• The remote video view
• The end-call button

When you use the UI setting of the demo project, you can see the following interface:

2. Initialize IRtcEngine

Create and initialize the IRtcEngine object before calling any other Agora APIs.

In this step, you need to use the App ID of your project. Refer to Get Started With Agora to create an Agora project and get the App ID in Console.

Call the createAgoraRtcEngine method and the initialize method, and pass in the App ID to initialize the IRtcEngine object.

You can also listen for callback events, such as when the local user joins or leaves the channel.

CAgoraObject *CAgoraObject::GetAgoraObject(LPCTSTR lpAppId)
{
    if (m_lpAgoraObject == NULL)
        m_lpAgoraObject = new CAgoraObject();
    if (m_lpAgoraEngine == NULL)

        // Create the instance.
        m_lpAgoraEngine = (IRtcEngine *)createAgoraRtcEngine();
    if (lpAppId == NULL)
        return m_lpAgoraObject;
    RtcEngineContext ctx;

    // Add the register events and callbacks.
    ctx.eventHandler = &m_EngineEventHandler;
#ifdef UNICODE
    char szAppId[128];
    ::WideCharToMultiByte(CP_ACP, 0, lpAppId, -1, szAppId, 128, NULL, NULL);

    // Input your App ID.
    ctx.appId = szAppId;
#else
    ctx.appId = lpAppId;
#endif

    // Initialize the IRtcEngine object.
    m_lpAgoraEngine->initialize(ctx);
    return m_lpAgoraObject;
}

// Inherit the events and callbacks of IRtcEngineEventHandler.
class CAGEngineEventHandler :
    public IRtcEngineEventHandler
{
public:
    CAGEngineEventHandler(void);
    ~CAGEngineEventHandler(void);
    void SetMsgReceiver(HWND hWnd = NULL);
    HWND GetMsgReceiver() {return m_hMainWnd;};

    // Listen for the onJoinChannelSuccess callback.
    // This callback occurs when the local user successfully joins the channel.
    virtual void onJoinChannelSuccess(const char* channel, uid_t uid, int elapsed);

    // Listen for the onLeaveChannel callback.
    // This callback occurs when the local user successfully leaves the channel.
    virtual void onLeaveChannel(const RtcStats& stat);

    // Listen for the onUserJoined callback.
    // This callback occurs when the remote user successfully joins the channel.
    // After receiving this callback, immediately call setupRemoteVideo to set the remote video view.
    virtual void onUserJoined(uid_t uid, int elapsed) override;

    // Listen for the onUserOffline callback.
    // This callback occurs when the remote user leaves the channel or drops offline.
    virtual void onUserOffline(uid_t uid, USER_OFFLINE_REASON_TYPE reason);
private:
    HWND        m_hMainWnd;
};

3. Set the local video view

After initializing the IRtcEngine object, set the local video view before joining the channel so that you can see yourself in the call. Follow these steps to configure the local video view:

• Call the enableVideo method to enable the video module.
• Call the setupLocalVideo method to configure the local video display settings.

// Enable the video module.
m_lpAgoraObject->GetEngine()->enableVideo();

VideoCanvas vc;
vc.uid = 0;
vc.view = m_wndLocal.GetSafeHwnd();
vc.renderMode = RENDER_MODE_FIT;
// Set the local video view.
m_lpAgoraObject->GetEngine()->setupLocalVideo(vc);

4. Join a channel

After initializing the IRtcEngine object and setting the local video view, you can call the joinChannel method to join a channel. In this method, set the following parameters:

• channelName: Specify the channel name that you want to join.

• token: Pass a token that identifies the role and privilege of the user. You can set it as one of the following values:

  • A temporary token generated in Console. A temporary token is valid for 24 hours. For details, see Get a Temporary Token. When joining a channel, ensure that the channel name is the same with the one you use to generate the temporary token.
  • A token generated at the server. This applies to scenarios with high-security requirements. For details, see Generate a token from Your Server. When joining a channel, ensure that the channel name and uid is the same with those you use to generate the token.
  • If your project has enabled the app certificate, ensure that you provide a token.
  • Ensure that you do not set token as "".

• uid: ID of the local user that is an integer and should be unique. If you set uid as 0, the SDK assigns a user ID for the local user and returns it in the onJoinChannelSuccess callback.

  Once the user joins the channel, the user subscribes to the audio and video streams of all the other users in the channel by default, giving rise to usage and billing calculation. If you do not want to subscribe to a specified stream or all remote streams, call the mute methods accordingly.

For more details on the parameter settings, see joinChannel.

BOOL CAgoraObject::JoinChannel(LPCTSTR lpChannelName, UINT nUID,LPCTSTR lpToken)
{
    int nRet = 0;
#ifdef UNICODE
    CHAR szChannelName[128];
    ::WideCharToMultiByte(CP_UTF8, 0, lpChannelName, -1, szChannelName, 128, NULL, NULL);
    char szToken[128];
    ::WideCharToMultiByte(CP_UTF8, 0, lpToken, -1, szToken, 128, NULL, NULL);
    if(0 == _tcslen(lpToken))
        nRet = m_lpAgoraEngine->joinChannel(NULL, szChannelName, NULL, nUID);
    else
        // Join a channel with a token.
        nRet = m_lpAgoraEngine->joinChannel(szToken, szChannelName, NULL, nUID);
#else
    if(0 == _tcslen(lpToken))
        nRet = m_lpAgoraEngine->joinChannel(NULL, lpChannelName, NULL, nUID);
    else
        nRet = m_lpAgoraEngine->joinChannel(lpToken, lpChannelName, NULL, nUID);
#endif
    if (nRet == 0)
        m_strChannelName = lpChannelName;
    return nRet == 0 ? TRUE : FALSE;
}

5. Set the remote video view

In a video call, you should be able to see other users too. This is achieved by calling the setupRemoteVideo method after joining the channel.

Shortly after a remote user joins the channel, the SDK gets the remote user's ID in the onUserJoined callback. Call the setupRemoteVideo method in the callback, and pass in the uid to set the video view of the remote user.

// Listen for the onUserJoined callback.
// After receiving this callback, immediately call setupRemoteVideo to set the remote video view.
LRESULT CAgoraTutorialDlg::OnEIDUserJoined(WPARAM wParam, LPARAM lParam)
{
    LPAGE_USER_JOINED lpData = (LPAGE_USER_JOINED)wParam;
    VideoCanvas vc;
    vc.renderMode = RENDER_MODE_FIT;
    vc.uid = lpData->uid;
    vc.view = m_wndRemote.GetSafeHwnd();
    // Set the remote video view.
    m_lpAgoraObject->GetEngine()->setupRemoteVideo(vc);
    delete lpData;
    return 0;
}

6. Leave the channel

Call the leaveChannel method to leave the current call according to your scenario, for example, when the call ends, when you need to close the app, or when your app runs in the background.

BOOL CAgoraObject::LeaveChannel()
{
    m_lpAgoraEngine->stopPreview();
    // Leave the current channel.
    int nRet = m_lpAgoraEngine->leaveChannel();
    return nRet == 0 ? TRUE : FALSE;
}


void CAgoraObject::CloseAgoraObject()
{
    if(m_lpAgoraEngine != NULL)
        // Release the IRtcEngine object.
        m_lpAgoraEngine->release();
    if(m_lpAgoraObject != NULL)
        delete m_lpAgoraObject;
    m_lpAgoraEngine = NULL;
    m_lpAgoraObject = NULL;
}

Run the project

Run the project on your Windows device. You can see both the local and remote video views when you successfully start a one-to-one video call in your app.

Reference

• How can I set the log file?
• How can I solve black screen issues?
• How can I implement call notification in a call application?