Live Screen Broadcast with ReplayKit

WWDC 2018

ReplayKit

• Capture
  - Screen visuals
  - App audio
  - Microphone input
• Record and share
• Broadcast live
• HD quality capture
• Low latency
• Low performance impact
• Minimal power usage
• Privacy safeguards

Live Broadcast

• Broadcast live to 3rd party broadcast services (ex. Facebook)
• Stream audio and visuals directly from device
• Provide commentary with microphone and camera (iOS)
• Content is secure and only accessible to the broadcast service
• Usage examples
  - Stream gameplay to Mobcrush or YouTube
  - Mirror screen on a WebEx call
  - Work with customer support via TeamViewerQS
  - Stream a drawing app to Facebook

ReplayKit vs ReplayKit 2

In-App Broadcast

• Your app or game
  - Provides the content — visuals and audio
  - Starts and stops the boardcast
• Broadcaster app
  - Provides sign-in and upload extensions
  - Streams content to their network

iOS System Broadcast

• Broadcasts all onscreen activity (and sounds)
• Start and stop from Control Center
• Systemwide, continuous session
  - Home screen
  - Moving app to app
• Build-in to iOS 11 and above

System Broadcast Picker

• Your app can initiate an iOS system broadcast session
• Simple 1-button UI
• No compromises for privacy
• Secure architecture
• New in iOS 12

preferredExtension

• Pair broadcast picker to a particular extension
• Assign bundle identifier of your extension
• Initialize before view is presented

RPSystemBroadcastPickerView

• Brings up system broadcast picker
• Allows to configure broadcast picker
• Doesn’t own any state of the session

Broadcast App and Extension

• Broadcast Application
  - Account sign-in, broadcast title
• Broadcast Upload Extension
  - Encode samples, upload to service

Broadcast Upload Extension

• Receives audio and video samples
• Encodes and uploads video stream
• Handles device orientation changes
• Annotates broadcast with app information

Broadcast Extension Template

Broadcast Lifecycle

Handling Sign-In and Broadcast Setup

Broadcast application

Initialization

Handling broadcastStarted

Processing Media Samples

Handling Application Information

Handling ‘ broadcastFinished ’

Handling Sign-In

Protecting Content

UIScreen.isCaptured

• Prevent capturing of audio and video content of your app
• Stop media playback or displaying sensitive content
  - Check value of UIScreen.captured
  - Register for UIScreenCapturedDidChangeNotification
  - Check UIScreen.screens.count to allow screen mirroring