iOS/macOS Swift SDK for LiveKit

Official Client SDK for LiveKit. Easily add video & audio capabilities to your iOS/macOS apps.

Docs & Example app

Docs and guides are at https://docs.livekit.io.

There is full source code of a iOS/macOS Swift UI Example App.

For minimal examples view this repo 👉 Swift SDK Examples

Installation

LiveKit for Swift is available as a Swift Package.

Package.swift

Add the dependency and also to your target

let package = Package(
  ...
  dependencies: [
    .package(name: "LiveKit", url: "https://github.com/livekit/client-sdk-swift.git", .upToNextMajor("1.0.0")),
  ],
  targets: [
    .target(
      name: "MyApp",
      dependencies: ["LiveKit"]
    )
  ]
}

XCode

Go to Project Settings -> Swift Packages.

Add a new package and enter: https://github.com/livekit/client-sdk-swift

iOS Usage

LiveKit provides an UIKit based VideoView class that renders video tracks. Subscribed audio tracks are automatically played.

import LiveKit
import UIKit

class RoomViewController: UIViewController {

    lazy var room = Room(delegate: self)

    lazy var remoteVideoView: VideoView = {
        let videoView = VideoView()
        view.addSubview(videoView)
        // additional initialization ...
        return videoView
    }()

    lazy var localVideoView: VideoView = {
        let videoView = VideoView()
        view.addSubview(videoView)
        // additional initialization ...
        return videoView
    }()

    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .white

        let url: String = "ws://your_host"
        let token: String = "your_jwt_token"

        room.connect(url, token).then { room in

            // Publish camera & mic
            room.localParticipant?.setCamera(enabled: true)
            room.localParticipant?.setMicrophone(enabled: true)

        }.catch { error in 
            // failed to connect
        }
    }
}

extension RoomViewController: RoomDelegate {

    func room(_ room: Room, localParticipant: LocalParticipant, didPublish publication: LocalTrackPublication) {
        guard let track = publication?.track as? VideoTrack else {
            return
        }
        DispatchQueue.main.async {
            localVideoView.track = track
        }
    }
    
    func room(_ room: Room, participant: RemoteParticipant, didSubscribe publication: RemoteTrackPublication, track: Track) {
        guard let track = track as? VideoTrack else {
          return
        }
        DispatchQueue.main.async {
            remoteVideoView.track = track
        }
    }
}

Thread safety

Since VideoView is a UI component, all operations (read/write properties etc) must be performed from the main thread.

Other core classes can be accessed from any thread.

Delegates will be called on the SDK's internal thread. Make sure any access to the UI is within the main thread, for example by using DispatchQueue.main.async.

Memory management

It is recommended to use weak var when storing references to objects created and managed by the SDK, such as Participant, TrackPublication etc. These objects are invalid when the Room disconnects, and will be released by the SDK. Holding strong reference to these objects will prevent releasing Room and other internal objects.

VideoView.track property does not hold strong reference, so it's not required to set it to nil.

iOS Simulator limitations

• Currently, VideoView will use OpenGL for iOS Simulator.
• Publishing the camera track is not supported by iOS Simulator.

ScrollView performance

It is recommended to turn off rendering of VideoViews that scroll off the screen and isn't visible by setting false to isEnabled property and true when it will re-appear to save CPU resources.

UICollectionViewDelegate's willDisplay / didEndDisplaying has been reported to be unreliable for this purpose. Specifically, in some iOS versions didEndDisplaying could get invoked even when the cell is visible.

The following is an alternative method to using willDisplay / didEndDisplaying :

// 1. define a weak-reference set for all cells
private var allCells = NSHashTable<ParticipantCell>.weakObjects()

// in UICollectionViewDataSource...
public func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {

    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: ParticipantCell.reuseIdentifier, for: indexPath)

    if let cell = cell as? ParticipantCell {
        // 2. keep weak reference to the cell
        allCells.add(cell)

        // configure cell etc...
    }

    return cell
}

// 3. define a func to re-compute and update isEnabled property for cells that visibility changed
func reComputeVideoViewEnabled() {

    let visibleCells = collectionView.visibleCells.compactMap { $0 as? ParticipantCell }
    let offScreenCells = allCells.allObjects.filter { !visibleCells.contains($0) }

    for cell in visibleCells.filter({ !$0.videoView.isEnabled }) {
        print("enabling cell#\(cell.hashValue)")
        cell.videoView.isEnabled = true
    }

    for cell in offScreenCells.filter({ $0.videoView.isEnabled }) {
        print("disabling cell#\(cell.hashValue)")
        cell.videoView.isEnabled = false
    }
}

// 4. set a timer to invoke the func
self.timer = Timer.scheduledTimer(withTimeInterval: 0.1, repeats: true, block: { [weak self] _ in
    self?.reComputeVideoViewEnabled()
})

// alternatively, you can call `reComputeVideoViewEnabled` whenever cell visibility changes (such as scrollViewDidScroll(_:)),
// but this will be harder to track all cases such as cell reload etc.

For the full example, see 👉 UIKit Minimal Example

Getting help / Contributing

Please join us on Slack to get help from our devs / community members. We welcome your contributions(PRs) and details can be discussed there.