Rendering Host and Audience Views - iOS
In a live stream setup, only hosts (participants in SEND_AND_RECV
mode) can broadcast their audio and video. Audience members (in RECV_ONLY
mode) are passive viewers who do not share their audio/video.
To ensure optimal performance and a clean user experience, your app should:
- Render video only for hosts (i.e., participants in
SEND_AND_RECV
mode). - Display the total audience count to give context on viewership without rendering individual audience tiles.
Filtering and Rendering Hosts
The steps involved in rendering the audio and video of hosts are as follows.
- Filtering Hosts and Checking their Mic/Webcam Status
- Rendering Video Streams of Hosts
- Handling Audience Views
1. Filtering Hosts and Checking their Mic/Webcam Status
In a live stream, only participants in SEND_AND_RECV
mode (i.e., hosts) actively share their audio and video. To render their streams, begin by accessing all participants using Meeting
classs. Then, filter out only those in SEND_AND_RECV
mode.
For each of these participants, use the Participant
class, which provides real-time information like displayName, micOn, and webcamOn. Display their name along with the current status of their microphone and webcam. If the webcam is off, show a simple placeholder with their name. If it's on, render their video feed. This ensures only hosts are visible to the audience, keeping the experience clean and intentional.
In a live stream, only participants in SEND_AND_RECV
mode (i.e., hosts) actively share their audio and video. To render their streams, begin by filtering all participants to show only those in SEND_AND_RECV
mode.
// Function to get visible participants (hosts only)
private func getVisibleParticipants() -> [Participant] {
// Only show participants who are in SEND_AND_RECV mode
return liveStreamViewController.participants.filter { participant in
participant.mode == .SEND_AND_RECV
}
}
In the LiveStreamViewController
class, we track the microphone status of each participant:
// Inside LiveStreamViewController's ParticipantEventListener implementation
func onStreamEnabled(_ stream: MediaStream, forParticipant participant: Participant) {
DispatchQueue.main.async {
// Only handle streams for SEND_AND_RECV participants
if participant.mode == .SEND_AND_RECV {
if let track = stream.track as? RTCVideoTrack {
if case .state(let mediaKind) = stream.kind, mediaKind == .video {
self.participantVideoTracks[participant.id] = track
self.participantCameraStatus[participant.id] = true
}
}
if case .state(let mediaKind) = stream.kind, mediaKind == .audio {
self.participantMicStatus[participant.id] = true
}
} else {
// For RECV_ONLY participants, ensure their tracks are removed
self.participantVideoTracks.removeValue(forKey: participant.id)
self.participantCameraStatus[participant.id] = false
self.participantMicStatus[participant.id] = false
}
}
}
func onStreamDisabled(_ stream: MediaStream, forParticipant participant: Participant) {
DispatchQueue.main.async {
if case .state(let mediaKind) = stream.kind {
switch mediaKind {
case .video:
self.participantVideoTracks.removeValue(forKey: participant.id)
self.participantCameraStatus[participant.id] = false
case .audio:
self.participantMicStatus[participant.id] = false
}
}
}
}
Then create a view for displaying each participant's video along with their name and microphone status:
struct ParticipantContainerView: View {
let participant: Participant
@ObservedObject var liveStreamViewController: LiveStreamViewController
// Name and mic status overlay
private var nameAndMicOverlay: some View {
VStack {
Spacer()
HStack {
Text(participant.displayName)
.foregroundColor(.white)
.padding(.horizontal, 8)
.padding(.vertical, 4)
.background(Color.black.opacity(0.5))
.cornerRadius(4)
Image(systemName: liveStreamViewController.participantMicStatus[participant.id] ?? false ? "mic.fill" : "mic.slash.fill")
.foregroundColor(liveStreamViewController.participantMicStatus[participant.id] ?? false ? .green : .red)
.padding(4)
.background(Color.black.opacity(0.5))
.clipShape(Circle())
Spacer()
}
.padding(8)
}
}
var body: some View {
// Only render if participant is in SEND_AND_RECV mode
if participant.mode == .SEND_AND_RECV {
ZStack {
participantView(participant: participant, liveStreamViewController: liveStreamViewController)
nameAndMicOverlay
}
.background(Color.black.opacity(0.9))
.cornerRadius(10)
.shadow(color: Color.black.opacity(0.7), radius: 10, x: 0, y: 5)
}
}
private func participantView(participant: Participant, liveStreamViewController: LiveStreamViewController) -> some View {
ZStack {
ParticipantView(participant: participant, liveStreamViewController: liveStreamViewController)
}
}
}
2. Rendering Video Streams of Hosts
Once you've filtered for participants in SEND_AND_RECV
mode (i.e., hosts), you can use the Participant
class to access their real-time data, including their webcamStream, webcamOn, and whether they are the local participant.
To render the video stream of a participant, we need to create a view that handles the WebRTC video track.
First, we define a VideoView
class:
class VideoView: UIView {
var videoView: RTCMTLVideoView = {
let view = RTCMTLVideoView()
view.videoContentMode = .scaleAspectFill
view.backgroundColor = UIColor.black
view.clipsToBounds = true
view.transform = CGAffineTransform(scaleX: 1, y: 1)
return view
}()
init(track: RTCVideoTrack?, frame: CGRect) {
super.init(frame: frame)
backgroundColor = .clear
// Set videoView frame to match parent view
videoView.frame = bounds
DispatchQueue.main.async {
self.addSubview(self.videoView)
self.bringSubviewToFront(self.videoView)
track?.add(self.videoView)
}
}
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func layoutSubviews() {
super.layoutSubviews()
// Update videoView frame when parent view size changes
videoView.frame = bounds
}
}
Then create a SwiftUI wrapper to use this UIKit view:
struct VideoStreamView: UIViewRepresentable {
let track: RTCVideoTrack
func makeUIView(context: Context) -> VideoView {
let view = VideoView(track: track, frame: .zero)
return view
}
func updateUIView(_ uiView: VideoView, context: Context) {
track.add(uiView.videoView)
}
}
Now create a participant view to display either the video or a placeholder:
struct ParticipantView: View {
let participant: Participant
@ObservedObject var liveStreamViewController: LiveStreamViewController
var body: some View {
ZStack {
if participant.mode == .SEND_AND_RECV,
let track = liveStreamViewController.participantVideoTracks[participant.id] {
VideoStreamView(track: track)
} else {
Color.black.opacity(1.0)
VStack {
if participant.mode == .RECV_ONLY {
Text("Viewer")
.foregroundColor(.white)
Text(participant.displayName)
.foregroundColor(.gray)
.font(.caption)
} else {
Text("No media")
.foregroundColor(.white)
}
}
}
}
}
}
3. Handling Audience View
For audience members, we provide a different set of controls and manage their view state. The main distinction is determining whether the current participant is in audience mode:
private var isAudienceMode: Bool {
// Derive audience mode from the current participant's mode
if let localParticipant = liveStreamViewController.participants.first(where: { $0.isLocal }) {
return localParticipant.mode == .RECV_ONLY
}
return currentMode == .RECV_ONLY
}
Certainly! You can refer to the videosdk-ils-iOS-sdk-example directory in the official VideoSDK iOS example repository for a comprehensive implementation of interactive live streaming features, including participant management and UI controls.
API Reference
The API references for all the methods and events utilized in this guide are provided below.
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