Quickstart

This page provides a step-by-step guide on how to create a basic real-time app using the Agora RTC SDK. The same steps apply whether you're building voice calling, video calling, interactive live streaming, or broadcast streaming — only a few configuration values change based on your use case.

Understand the tech

To start a real-time session, implement the following steps in your app:

• Initialize the engine: Before calling other APIs, create and initialize an engine instance.

• Join a channel: Call methods to create and join a channel.

  • Join as a host: A live streaming event has one or more hosts. A host publishes audio and video to the channel and can also subscribe to streams from other hosts.

  • Join as audience: Audience members can only subscribe to streams published by hosts.

  Note

  For the voice calling and video calling use cases, each user joins as a host.

• Send and receive audio and video: Hosts publish streams to the channel. Audience members subscribe to audio and video streams published by hosts.

• For streaming applications, set the latency level based on your use case:

  • Interactive live streaming: Optimized for real-time interaction with ultra-low latency. Use this when hosts and audience need to interact quickly, such as in live Q&A sessions, interactive classrooms, or auctions.

  • Broadcast streaming: Optimized for scalability with slightly higher latency. Use this for large-scale events where one-way broadcasting is sufficient, such as concerts, sports events, or news broadcasts.

Prerequisites

• A camera and a microphone.

• A valid Agora account and project. See Agora account management for details.

• Unreal Engine 4.27 or higher.

• Prepare your development environment according to your target platform and engine version:

  Dev environment requirements	Other requirements
  Android	-
  iOS	A valid Apple developer signature.
  macOS	A valid Apple developer signature.
  Windows	32-bit Windows supports Unreal Engine 4 only. To use Unreal Engine with 32-bit Windows, uncomment the code related to Win32 in AgoraPluginLibrary.Build.cs.

• Two physical devices for testing.

Set up your project

Install the SDK

Take the following steps to add the RTC SDK to your project:

1. Download the latest version of Agora Unreal RTC SDK from Download SDKs and unzip it.
2. In your project root folder, create a Plugins folder.
3. Copy AgoraPlugin from the Unreal SDK folder to Plugins.

Implement Realtime Communication

This section guides you through the implementation of basic real-time audio and video interaction in your app.

Create a level

1. In the Content folder of the Content Browser, right-click and select Level to create a Level Blueprint and name it BasicVideoCallScene.

2. Double-click BasicVideoCallScene and click Blueprints > Open Level Blueprint above the editor to open the level blueprint.

   

Implement basic processes

In the My Blueprint panel, double-click Graphs > EventGraph to open the event graph. You see two event nodes: Event BeginPlay (game starts) and Event End Play (game ends). Create event nodes with the corresponding functions and variables, and connect them as shown in the following figure to implement the Realtime Communication logic:

The following table lists the main nodes:

* Native nodes are nodes that come with the blueprint and can be added and called directly.
** Custom nodes are not included in the blueprint. You create a custom function before you can add the corresponding node.

Add channel-related variables

Add variables to create an engine instance and join a channel.

1. Create three variables:

   Token, ChannelId, and AppId. Select the Variable Type as String.

2. In the Load Agora Config function, add the Sequence node, and then connect Set Token, Set Channel Id, and Set App Id respectively. Fill in the token, channel name, and app ID values obtained from Agora Console.

   

Initialize RTC engine

1. If your target platform is Android, check whether system permissions have been granted before initializing the RTC engine. Refer to the following figure to create nodes for adding permissions to access the microphone and camera in the CheckPermission function.

   

   Note

   If your target platform is macOS or iOS, please refer to How do I add the permissions needed for real-time interaction to my Unreal Engine project?

2. To initialize the RTC engine, in the InitRtcEngine function, create and connect nodes as shown in the following figure:

   

3. Create IRtcEngine and IRtcEngineEventHandler.

   1. To store references to the engine and event-handler interface classes, create RtcEngine and EventHandler variables, and set the Variable Type to Agora Rtc Engine and IRtc Engine Event Handler, respectively.

   2. Add two Construct Object From Class nodes, set Class to Agora Rtc Engine and IRtc Engine Event Handler respectively. Connect to Set Rtc Engine and Set Event Handler, respectively.

4. Bind IRtcEngineEventHandler class-related callback functions.

   1. Create onJoinChannelSuccess, onLeaveChannel, onUserJoined, and onUserOffline callback functions. Refer to the following table to configure the input parameters of the callbacks:

      Callback	Description	Input parameters
      FOnJoinChannelSuccess	The local user successfully joined a channel.	channel: (String) Channel name. uid: (Integer64) The ID of the user joining the channel. elapsed: (Integer) The time (in milliseconds) that elapsed from the local call to JoinChannel till the occurrence of this event.
      FOnLeaveChannel	The local user left the channel.	- stats: Call statistics.
      FOnUserJoined	A remote user joined the current channel.	uid: (Integer64) The user ID of the remote user joining the channel. elapsed: (Integer) The time (in milliseconds) that elapsed from the local call to JoinChannel till the occurrence of this event.
      FOnUserOffline	A remote user left the current channel.	uid: (Integer64) The ID of the user going offline. reason: Offline reason. For details, see EUSER_OFFLINE_REASON_TYPE.

   2. Create a Bind Event function. In this function, add a Sequence node, and then bind the onJoinChannelSuccess, onLeaveChannel, onUserJoined, and onUserOffline callback events.

      

5. IRtcEngine initialization

   1. Call Initialize to initialize the RTC engine.
   2. Connect to the RtcEngineContext configuration IRtcEngine instance.

Set the channelProfile, clientRoleType, and audienceLatencyLevel according to your use case:

Bind UI events

To bind UI events:

1. Create and implement the OnJoinChannelClicked event callback.

   

   1. Call Enable Video and Enable Audio to enable the video and audio modules.
   2. Call Join Channel to join the channel.
   3. Set the following parameters in Make ChannelMediaOptions:
      • Set Publish Camera Track to AGORA TRUE VALUE to publish the video stream recorded by the camera.
      • Set Publish Microphone Track to AGORA TRUE VALUE to publish the audio stream recorded by the microphone.
      • Set Auto Subscribe Video to AGORA TRUE VALUE to automatically subscribe to all video streams.
      • Set Auto Subscribe Audio to AGORA TRUE VALUE to automatically subscribe to all audio streams.
      • Check Client Role Type Set Value and set Client Role Type to CLIENT_ROLE_BROADCASTER or CLIENT_ROLE_AUDIENCE, to set the user role to host or audience.
      • Check Channel Profile Set Value and set Channel Profile to CHANNEL_PROFILE_LIVE_BROADCASTING.

2. Create and implement the OnLeaveChannelClicked event callback. When the event is triggered, call Leave Channel to leave the channel.

   

3. In the Bind UIEvent function, refer to the figure below to bind the OnJoinChannelClicked and OnLeaveChannelClicked callback functions to the Join Channel and Leave Channel buttons respectively. When the button is clicked, the corresponding event callback is triggered.

   

Set up local and remote views

1. Create and implement the MakeVideoView function to load the view when local or remote users join the channel:

   

   1. In this function, create SavedUID, SavedSourceType, SavedChannelID local variables, set the Variable Type to Integer64, VIDEO_SOURCE_TYPE, and String, respectively. Save the variables for use when loading the view later.
   2. Create a local view. In the local view, if the UID is 0, a value is randomly assigned by the SDK, and the video source type is VIDEO_SOURCE_CAMERA_PRIMARY (the first camera).
   3. Create a remote view. In the remote view, the uid is the uid sent from the remote end, and the video source type is VIDEO_SOURCE_REMOTE (remote video obtained from the network).

2. Create and implement the ReleaseVideoView function to release the view when a local or remote user leaves the channel.

   

   1. In this function, create SavedUID, SavedSourceType, and SavedChannelID local variables, set the Variable Type to Integer64, VIDEO_SOURCE_TYPE, and String, respectively. Save the variables for use when releasing the view later.
   2. Release the local view.
   3. Release the remote view.

Implement callback function

Configure the previously created onJoinChannelSuccess, onLeaveChannel, onUserJoined, and onUserOffline callback functions as follows:

1. After the local user successfully joins the channel, the onJoinChannelSuccess callback is triggered and the local view is created. The uid is set to 0 by default, but it is assigned a random value by the SDK. The video source type is VIDEO_SOURCE_CAMERA_PRIMARY (first camera):

   

2. After the local user leaves the channel, the onLeaveChannel callback is triggered which releases the local view:

   

3. When a remote user joins the channel, the onUserJoined callback is triggered to create a remote view. uid is the uid sent from the remote end, and the video source type is VIDEO_SOURCE_REMOTE (remote video obtained from the network):

   

4. When a remote user leaves the channel, the onUserOffline callback is triggered to release the remote view:

   

Leave the channel and release resources

To leave the channel, implement the following steps:

1. Leave the channel.
2. Unregister Agora backend event callback.
3. Destroy IRtcEngineObject to release all resources used by Agora SDK.

Refer to the figure below to implement the UnInitRtcEngine function:

Test the sample code

Take the following steps to test the sample code:

1. In the Load Agora Config function, fill in the app ID, channel name, and temporary token for your project.

2. In the Unreal Editor, click Play to run your project. Click JoinChannel to join a channel.

3. Invite a friend to run the demo client on a second device. Use the same app ID, channel name, and token to join. After your friend joins successfully, you can hear and see each other.

Reference

This section contains content that completes the information on this page, or points you to documentation that explains other aspects of this product.

• If a firewall is deployed in your network environment, refer to Connect with Cloud Proxy to use Agora services normally.

Next steps

After implementing the quickstart sample, read the following documents to learn more:

• To ensure communication security in a test or production environment, best practice is to obtain and use a token from an authentication server. For details, see Secure authentication with tokens.

Sample project

Agora provides open source sample projects on GitHub for your reference. Download or view the JoinChannelVideo project for a more detailed example.

Frequently asked questions

• How can I listen for audience joining or leaving a channel?
• How can I fix black screen issues?
• Why can't I turn on the camera?
• How can I solve channel-related issues?
• How can I set the log file?

See also

• SDK error codes
• Connection status management