Minimal Subscribe

This example shows the fewest lines of code needed to subscribe to a live stream with the Red5 Pro iOS SDK. Unlike publishing, subscribing does not require a preview step — you build the client, attach a renderer for the incoming video, and call subscribe().

What You Will Learn

How to build a Red5WebrtcClient configured for subscribing
How to attach a remote video renderer
The subscribe lifecycle and its delegate callbacks
How to cleanly stop a subscribe session

Prerequisites

Add the Red5 Pro iOS SDK (Red5WebRTCKit) to your Xcode project via Swift Package Manager.
Copy Config.swift into your project and fill in your server details:

enum Config {
    static let serverIP   = "your-server-ip"
    static let port       = 8554
    static let appName    = "live"
    static let streamName = "stream1"
    static let licenseKey = "XXXX-XXXX-XXXX-XXXX"
}

Ensure a publisher is already streaming to streamName on your server before subscribing.

Key API Calls

1. Build the Client

The builder configuration is the same as for publishing. The SDK infers the role (subscriber vs publisher) from which action you call first.

client = Red5WebrtcClientBuilder()
    .setServerIp(Config.serverIP)
    .setPort(Config.port)
    .setAppName(Config.appName)
    .setStreamName(Config.streamName)
    .setLicenseKey(Config.licenseKey)
    .setVideoEnabled(true)
    .setAudioEnabled(true)
    .setEventListener(self)
    .build()

client?.setVideoRenderer(renderer)

2. Subscribe

No preview step is needed. Call subscribe() directly:

client?.subscribe()

3. Handle Incoming Stream

Show the video renderer once the stream arrives:

func onSubscribeStarted() {
    hasVideo = true   // show the RTCMTLVideoView in the UI
}

4. Stop

client?.stopSubscribe()

Lifecycle Summary

Red5WebrtcClientBuilder.build()
        ↓
client.subscribe()
        ↓
onSubscribeStarted()        ← stream is playing
        ↓
client.stopSubscribe()
        ↓
onSubscribeStopped()

Difference from Publish

	Publish	Subscribe
Preview step required	Yes — `startPreview()`	No
License callback needed before action	Yes	No (but still fires)
First action to call	`startPreview()`	`subscribe()`
Video direction	Local camera → server	Server → local renderer

Source Code

The full example is available in the red5pro-ios-sdk-examples repository under 02-MinimalSubscribe/.