Interface ILocalVideoTrack

LocalVideoTrack is the basic interface for local video tracks, providing the main methods for local video tracks.

You can get create a local video track by calling AgoraRTC.createCustomVideoTrack or AgoraRTC.createScreenVideoTrack method.

Inherited from LocalVideoTrack, CameraVideoTrack is an interface for the video captured by a local camera and adds several camera-related functions.







  • sei-received(sei: Uint8Array): void
  • since


    Parsing SEI data from the H.264 video stream triggers this event, which returns the SEI data.


    • sei: Uint8Array

      SEI data in Uint8Array

    Returns void


  • since


    Indicates the visibility of the <video> HTML tag.

    The SDK triggers this event every 30 seconds.

    After you call, the SDK creates an <video> tag for playing video tracks. When localVideoTrack.isPlaying is true but you cannot see any video, this event helps you check whether the <video> tag is visible or not and learn the reason when the <video> tag is invisible.


    Returns void



enabled: boolean


isPlaying: boolean

Whether a media track is playing on the webpage:

  • true: The media track is playing on the webpage.
  • false: The media track is not playing on the webpage.


muted: boolean


processorDestination: IBaseProcessor


The destination of the current processing pipeline on the local video track.


trackMediaType: "audio" | "video"

The type of a media track:

  • "audio": Audio track.
  • "video": Video track.



  • since


    Clones the current video track to create a new video track.

    In scenarios such as video conferencing and online education, you can use this method to display the same video stream with two sets of display parameters, including resolution, frame rate, and bitrate. For example, you can have one display set to high-definition and the other to low-definition.


    Returns ILocalVideoTrack

    The newly generated video track.


  • close(): void
  • Closes a local track and releases the audio and video resources that it occupies.

    Once you close a local track, you can no longer reuse it.

    Returns void


  • getCurrentFrameData(): ImageData
  • since


    Gets the data of the video frame being rendered.

    You should call this method after calling play. Otherwise, the method call returns null.

    Returns ImageData

    An ImageData object that stores RGBA data. ImageData is a web API supported by the browser. For details, see ImageData.


  • getListeners(event: string): Function[]
  • Gets all the listeners for a specified event.


    • event: string

      The event name.

    Returns Function[]


  • getMediaStreamTrack(): MediaStreamTrack


  • getRTCRtpTransceiver(type?: StreamType): RTCRtpTransceiver | undefined



  • getTrackId(): string


  • getTrackLabel(): string
  • Gets the label of a local track.

    Returns string

    The label that the SDK returns may include:

    • The MediaDeviceInfo.label property, if the track is created by calling createMicrophoneAudioTrack or createCameraVideoTrack.
    • The sourceId property, if the track is created by calling createScreenVideoTrack.
    • The MediaStreamTrack.label property, if the track is created by calling createCustomAudioTrack or createCustomVideoTrack.


  • since


    Gets the visibility of the <video> HTML tag.

    After you call, the SDK creates an <video> tag for playing video tracks. When localVideoTrack.isPlaying is true but you cannot see any video, call this method to check whether the <video> tag is visible or not and learn the reason when the <video> tag is invisible.

    Returns CheckVideoVisibleResult | undefined

    The CheckVideoVisibleResult object. If this method returns undefined, it may be due to the following reasons:

    • localVideoTrack.isPlaying is false.
    • The <video> tag does not exist.
    • The <video> tag is not created by calling the play method.


  • off(event: string, listener: Function): void
  • Removes the listener for a specified event.


    • event: string

      The event name.

    • listener: Function

      The callback that corresponds to the event listener.

    Returns void


  • on(event: "track-ended", listener: typeof event_track_ended): void
  • on(event: "video-element-visible-status", listener: typeof event_video_element_visible_status): void
  • on(event: "transceiver-updated", listener: typeof event_transceiver_updated): void


  • once(event: string, listener: Function): void
  • Listens for a specified event once.

    When the specified event happens, the SDK triggers the callback that you pass and then removes the listener.


    • event: string

      The event name.

    • listener: Function

      The callback to trigger.

    Returns void


  • pipe(processor: IBaseProcessor): IBaseProcessor
  • Inserts a Processor to the local video track.


    • processor: IBaseProcessor

      The Processor instance. Each extension has a corresponding type of Processor.

    Returns IBaseProcessor

    The Processor instance.


  • Plays a remote video track on the web page.


    • element: string | HTMLElement

      Specifies a DOM element. The SDK will create a <video> element under the specified DOM element to play the video track. You can specify a DOM element in either of the following ways:

      • string: Specify the ID of the DOM element.
      • HTMLElement: Pass a DOM object.
    • Optional config: VideoPlayerConfig

      Sets the playback configurations, such as display mode and mirror mode. See VideoPlayerConfig. By default, the SDK enables mirror mode for a local video track.

    Returns void


  • removeAllListeners(event?: string): void
  • Removes all listeners for a specified event.


    • Optional event: string

      The event name. If left empty, all listeners for all events are removed.

    Returns void


  • replaceTrack(track: MediaStreamTrack, stopOldTrack: boolean): Promise<void>
  • since


    Replaces the local video track.

    You can call this method before or after publishing the local video stream:

    • If you call this method before publishing, the new video track is played locally.
    • If you call this method after publishing, the new video track is received by the remote user.

    The new video track can be retrieved by the ILocalVideoTrack.getMediaStreamTrack or mediaStream.getVideoTracks method. You can choose to either stop or retain the replaced track.


    • This method supports Chrome 65+, Safari, and the latest Firefox.
    • This method might not take effect on some mobile devices.
    • Agora recommends switching between video tracks that are of the same type and have the same encoder configurations for the following reasons:
      • If the video track types are different, such as replacing a CameraVideoTrack object with a ScreenVideoTrack object, the video is flipped horizontally due to the mirror effect enabled by default on CameraVideoTrack (see VideoPlayerConfig.mirror for details).
      • If the encoder configurations (encoderConfig) are different, the actual sending resolution or frame rate might be different from what you set.
    • The subscriber will not be notified if the track gets replaced.
    • To switch the media input devices, Agora recommends using ICameraVideoTrack.setDevice.


    // Current video track
    const localVideoTrack = await AgoraRTC.createCameraVideoTrack();
    // Gets the new video track (option one)
    const newTrack = localVideoTrack.getMediaStreamTrack();
    // Gets the new video track (option two)
    const newTrack = await navigator.mediaDevices.getUserMedia({audio: true, video: true}).then(mediaStream => mediaStream.getVideoTracks()[0]);
    // Replaces and stops the current video track
    await localVideoTrack.replaceTrack(newTrack, true);


    • track: MediaStreamTrack

      The new video track, which is a MediaStreamTrack object.

    • stopOldTrack: boolean

      Whether to stop the old video track:

      • true: Stops the old video track.
      • false: Retains the old video track.

    Returns Promise<void>


  • sendSeiData(sei: Uint8Array): void
  • Add the SEI data to the H.264 video stream.


    • sei: Uint8Array

    Returns void


  • setEnabled(enabled: boolean): Promise<void>
  • since


    Enables/Disables the track.

    After a track is disabled, the SDK stops playing and publishing the track.


    • enabled: boolean

      Whether to enable the track:

      • true: Enable the track.
      • false: Disable the track.

    Returns Promise<void>



  • setMuted(muted: boolean): Promise<void>
  • Sends or stops sending the media data of the track.



    If the track is published, a successful call of setMuted(true) triggers the user-unpublished event on the remote client, and a successful call of setMuted(false) triggers the user-published event.


    • muted: boolean

      Whether to stop sending the media data of the track:

      • true: Stop sending the media data of the track.
      • false: Resume sending the media data of the track.

    Returns Promise<void>


  • setOptimizationMode(mode: "balanced" | "motion" | "detail"): Promise<void>
  • since


    Sets the video transmission optimization mode.

    You can call this method during a video call, a live streaming or screen sharing to dynamically change the optimization mode. For example, during the screen sharing, before you change the shared content from text to video, you can change the optimization mode from "detail" to "motion" to ensure smoothness in poor network conditions.

    Note: This method supports Chrome only.


    • mode: "balanced" | "motion" | "detail"

      The video transmission optimization mode:

      • "balanced": Uses the default optimization mode.
        • For a screen-sharing video track, the default transmission optimization strategy is to prioritizes clarity.
        • For the other types of video tracks, the SDK may reduce the frame rate or the sending resolution in poor network conditions.
      • "detail": Prioritizes video quality.
        • The SDK ensures high-quality images by automatically calculating a minimum bitrate based on the capturing resolution and frame rate. No matter how poor the network condition is, the sending bitrate will never be lower than the minimum value.
        • In most cases, the SDK does not reduce the sending resolution, but may reduce the frame rate.
      • "motion": Prioritizes video smoothness.
        • In poor network conditions, the SDK reduces the sending bitrate to minimize video freezes.
        • In most cases, the SDK does not reduce the frame rate, but may reduce the sending resolution.

    Returns Promise<void>


  • stop(): void


  • unpipe(): void
  • since


    Removes the Processor inserted to the local video track.

    Returns void