Custom video source

Custom video capture refers to the collection of a video stream from a custom source. Unlike the default video capture method, custom video capture enables you to control the capture source, and precisely adjust video attributes. You can dynamically adjust parameters such as video quality, resolution, and frame rate to adapt to various application scenarios. For example, you can capture video from high-definition cameras, and drone cameras.

Agora recommends default video capture for its stability, reliability, and ease of integration. Custom video capture offers flexibility and customization for specific video capture scenarios where default video capture does not fulfill your requirements.

Video SDK provides a custom video track method for video self-collection. You create one or more custom video tracks, join channels and publish the created video tracks in each channel. You use the self-capture module to drive the capture device, and send the captured video frames to the SDK through the video track.

The following figure shows the video data transmission process when custom video capture is implemented in a single channel or multiple channels:

• Publish to a single channel

  

• Publish to multiple channels

  

Use custom video capture in the following industries and scenarios:

Specialized video processing and enhancement

In specific gaming or virtual reality scenarios, real-time effects processing, filter handling, or other enhancement effects necessitate direct access to the original video stream. Custom video capture facilitates this, enabling seamless real-time processing and enhances the overall gaming or virtual reality experience for a more realistic outcome.

High-precision video capture

In video surveillance applications, detailed observation and analysis of scene details is necessary. Custom video capture enables higher image quality and finer control over capture to meet the requirements of video monitoring.

Capture from specific video sources

Industries such as IoT and live streaming often require the use of specific cameras, monitoring devices, or non-camera video sources, such as video capture cards or screen recording data. In such situations, default Video SDK capture may not meet your requirements, necessitating use of custom video capture.

Seamless integration with specific devices or third-party applications

In smart home or IoT applications, transmitting video from devices to users' smartphones or computers for monitoring and control may require the use of specific devices or applications for video capture. Custom video capture facilitates seamless integration of specific devices or applications with the Video SDK.

Specific video encoding formats

In certain live streaming scenarios, specific video encoding formats may be needed to meet business requirements. In such cases, Video SDK default capture might not suffice, and custom video capture is required to capture and encode videos in specific formats.

Using custom video capture offers the following advantages:

More types of video streams

Custom video capture allows the use of higher quality and a greater variety of capture devices and cameras, resulting in clearer and smoother video streams. This enhances the user viewing experience and makes the product more competitive.

More flexible video effects

Custom video capture enables you to implement richer and more personalized video effects and filters, enhancing the user experience. You can implement effects such as beautification filters and dynamic stickers.

Adaptation to diverse scenario requirements

Custom video capture helps applications better adapt to the requirements of various scenarios, such as live streaming, video conferencing, and online education. You can customize different video capture solutions based on the scenario requirements to provide a more robust application.

Ensure that you have implemented the SDK quickstart in your project.

The figure below shows the workflow you need to implement to stream a custom video source in your app.

Take the following steps to implement this workflow:

1. Create a custom video track

   To create a custom video track and obtain the video track ID, call createCustomVideoTrack after initializing an instance of AgoraRtcEngineKit. To create multiple custom video tracks, call the method multiple times.

   customCamera?.trackId = agoraKit.createCustomVideoTrack()
   

2. Join a channel and publish the custom video track

   Call joinChannelByToken to join a single channel, or joinChannelExByToken to join multiple channels. In AgoraRtcChannelMediaOptions, set customVideoTrackId to the video track ID from the previous step and set publishCustomVideoTrack to true to publish the custom video track.

   • Join a single channel

     let option = AgoraRtcChannelMediaOptions()
     

     option.clientRoleType = .broadcaster
     

     option.autoSubscribeAudio = true
     

     option.autoSubscribeVideo = true
     

     // highlight-start
     

     // Publish the self-collected video stream
     

     option.publishCustomVideoTrack = true
     

     // Set custom video track ID
     

     option.customVideoTrackId = Int(customCamera?.trackId ?? 0)
     

     // highlight-end
     

     NetworkManager.shared.generateToken(channelName: channel, success: { token in
     

     // Join a single channel
     

     let result = self.agoraKit.joinChannel(byToken: token, channelId: channel, uid: 0, mediaOptions: option)
     

     if result != 0 {
     

     self.isProcessing = false
     

     self.showAlert(title: "Error", message: "joinChannel call failed: \(result), please check your params")
     

     }
     

     })
     

   • Publish custom video to multiple channels

     // To publish custom video tracks on multiple channels, set AgoraRtcChannelMediaOptions multiple times and call joinChannelEx multiple times.
     

     let option = AgoraRtcChannelMediaOptions()
     

     option.clientRoleType = .broadcaster
     

     option.autoSubscribeAudio = true
     

     option.autoSubscribeVideo = true
     

     // highlight-start
     

     // Publish the self-collected video stream
     

     option.publishCustomVideoTrack = true
     

     // Set custom video track ID
     

     option.customVideoTrackId = Int(trackId)
     

     // highlight-end
     

     let connection = AgoraRtcConnection()
     

     connection.localUid = uid
     

     connection.channelId = channelName
     

     NetworkManager.shared.generateToken(channelName: channelName, uid: uid) { token in
     

     // Join multiple channels
     

     let result = self.agoraKit.joinChannelEx(byToken: token,
     

     connection: connection,
     

     delegate: self,
     

     mediaOptions: option,
     

     joinSuccess: nil)
     

     if result != 0 {
     

     self.showAlert(title: "Error", message: "joinChannel call failed: \(result), please check your params")
     

     }
     

     }
     

3. Implement your self-capture module

   Agora provides the CustomVideoSourcePushMulti demo project that shows you how to read YUV format video data from a local file. In a production environment, create a custom video module for your device using Video SDK based on your business requirements.

4. Push video data to the SDK

   Use pushExternalVideoFrame to send the captured video frame to the SDK through the video track. Ensure that the videoTrackId matches the video track ID specified when joining the channel. In AgoraVideoFrame, you can set the pixel format, data type, timestamp, and other parameters of the video frame.

   The following code demonstrates how to push video data in the CVPixelBufferRef format. For other supported video frame formats, refer to the format field in AgoraVideoFrame.

   let videoFrame = AgoraVideoFrame()
   

   videoFrame.format = 12
   

   videoFrame.textureBuf = buffer
   

   videoFrame.rotation = Int32(rotation)
   

   agoraKit?.pushExternalVideoFrame(videoFrame, videoTrackId: trackId)
   
   Information

   To ensure audio and video synchronization, Agora recommends setting the time (timestamp) of AgoraVideoFrame to the system monotonic time. To retrieve the current monotonic time, call getCurrentMonotonicTimeInMs.

   Information

   If the captured custom video format is Texture and remote users experience flickering or distortion in the captured video, it is recommended to first duplicate the video data and then send both the original and duplicated video data back to the Video SDK. This helps eliminate anomalies during internal data encoding processes.

5. Destroy custom video track

   To stop publishing the custom video track, call destroyCustomVideoTrack. To destroy multiple video tracks, call destroyCustomVideoTrack multiple times.

   // Destroy the custom video track
   

   agoraKit.destroyCustomVideoTrack(UInt(userModel?.trackId ?? 0))
   

   // Leave the channel
   

   agoraKit.leaveChannelEx(connection) { state in
   

   LogUtils.log(message: "warning: \(state.description)", level: .info)
   

   }
   

To implement custom video rendering in your app, refer to the following steps:

1. Set up onCaptureVideoFrame or onRenderVideoFrame callback to obtain the video data to be played.
2. Implement video rendering and playback yourself.

info

In renderPixelBuffer or renderRawData, the rotation parameter of the video frame may not be 0. You need to set the rotation parameters yourself.

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

Agora provides the following open-source sample projects for your reference. Download the project or view the source code for a more detailed example.

• CustomVideoSourcePush: Video self-capture
• CustomVideoRender: Custom video rendering

• createCustomVideoTrack
• destroyCustomVideoTrack
• setExternalVideoSource
• pushExternalVideoFrame [2/2]
• onRenderVideoFrame(_:uid:channelId:)
• onCapture(_:sourceType:)
• getCurrentMonotonicTimeInMs
• joinChannelExbyToken