Getting Started: iOS

Contents

• Video API Overview
• Prerequisites
  • Get the Programmable Video iOS SDK
  • Get an API Key
  • Generate an Access Token
• Connect to a Room
  • Default Room Settings
  • Enabling Room Recordings
• Join a Room
• Set up local media
  • Specify tracks at connect time
  • Connect as a publish-only Participant
• Working with Remote Participants
  • Handle Connected Participants
  • Handle Participant Connection Events
  • Display a Remote Participant's Video
• Participating in a Room
  • Display a Camera Preview
  • Disconnect from a Room
• Server-side Control
• Getting help
  • Enabling Debug Logging

This guide provides you with an overview of the key objects you'll use in the Programmable Video API to build your video application with the Twilio Programmable Video iOS SDK.

Note: If you haven’t already done so, take a look at the open source video collaboration app and quickstart apps. Then come back to this guide for more detail on how to add video to your own app.

If you’ve worked with WebRTC in the past, you’ll find that Programmable Video provides a simple wrapper around WebRTC’s lower-level APIs to make it easy to build rich audio and video applications. You can still access lower-level primitives, but that’s not required to get started.

Additionally, Programmable Video provides the missing pieces required to use WebRTC to build sophisticated applications: Global STUN/TURN relays, media services for large-scale group conferences and recording, and signaling infrastructure are all included.

Video API overview

Let’s start with an overview of the Programmable Video API:

• A Room represents a real-time audio, video, and/or screen-share session, and is the basic building block for a Programmable Video application.
• In a Peer-to-peer Room, media flows directly between participants. Supports up to 10 participants in a mesh topology.
• In a Group Room, media is routed through Twilio's Media Servers. Supports up to 50 participants.
• Participants represent client applications that are connected to a Room and sharing audio and/or video media with one another.
• Tracks represent the individual audio and video media streams that are shared within a Room.
• LocalTracks represent the audio and video captured from the local microphone and camera.
• RemoteTracks represent the audio and video tracks from other participants connected to the Room.

The following code samples illustrate common tasks that you as a developer may wish to perform related to a Room and its Participants.

Prerequisites

To start using the iOS Programmable Video SDK in your apps, you need to perform a few basic tasks first.

1. Get the Programmable Video iOS SDK

The Twilio Video iOS SDK dynamic framework can be installed using Swift Package Manager, CocoaPods or manually, as you prefer.

Swift Package Manager

You can add Programmable Video for iOS by adding the https://github.com/twilio/twilio-video-ios repository as a Swift Package.

In your Build Settings, you will also need to modify Other Linker Flags to include -ObjC.

As of the latest release of Xcode, there is a known issue with consuming binary frameworks distributed via Swift Package Manager. The current workaround to this issue is to add a Run Script Phase to the Build Phases of your Xcode project. This Run Script Phase should come after the Embed Frameworks build phase. This new Run Script Phase should contain the following code:

find "${CODESIGNING_FOLDER_PATH}" -name '*.framework' -print0 | while read -d $'\0' framework
do
    codesign --force --deep --sign "${EXPANDED_CODE_SIGN_IDENTITY}" --preserve-metadata=identifier,entitlements --timestamp=none "${framework}"
done

CocoaPods

source 'https://github.com/CocoaPods/Specs'

platform :ios, '12.2'

target 'TARGET_NAME' do
    pod 'TwilioVideo', '~> 5'
end

Then run pod install to install the dependencies to your project.

Manual

TwilioVideo.xcframework is distributed as a dynamic iOS framework that you can drag and drop into your existing projects.

View all Video iOS Releases here or just download the latest Video dynamic framework here.

Once you've downloaded and unpacked the XCFramework, navigate to your Xcode project's General settings page. Drag and drop TwilioVideo.xcframework onto the Frameworks, Libraries, and Embedded Content section. Ensure that "Copy items if needed" is checked and press Finish. Ensure that "Embed & Sign" is selected.

In your Build Settings, you will also need to modify Other Linker Flags to include -ObjC.

Background Modes

To allow a connection to a Room to be persisted while an application is running in the background, you must select the Audio, AirPlay, and Picture in Picture background mode from the Capabilities project settings page.

User Permissions

Twilio Video requires user permission for features like sharing video from the camera or audio from the microphone. Consider how your applications might function with reduced functionality in case some permissions (like the camera) are declined.

• Custom audio devices do not require microphone permissions for playback only use cases. See video-quickstart-ios/issues/207 for more information.

Supported Devices

The iOS SDK supports iOS 12.2 or higher. It is built for arm64 and x86_64 architectures with Bitcode slices for arm64 devices.

Supported Xcode versions and Bitcode

The TwilioVideo.framework is built with Xcode 13. The framework can be consumed with previous versions of Xcode. However, re-compiling Bitcode when exporting for Ad Hoc or Enterprise distribution requires the use of Xcode 13.x.

2. Get an API Key

API Keys represent credentials to access the Twilio API. They are used for two purposes:

• to authenticate to the REST API.
• to create and revoke Access Tokens

For the purposes of this guide, we will create our API Key from the Twilio Console.

• Go to the API Keys section under Account in the Twilio Console.
• Click on “Create a New API Key”, add a friendly name and save your Key and Secret.

3. Generate an Access Token

To execute the code samples below, you'll need to generate an Access Token. An Access Token is a short-lived credential used to authenticate your client-side application to Twilio.

You can generate an Access Token using either the Twilio CLI or a Twilio helper library. For application testing purposes, the Twilio CLI provides a quick way to generate Access Tokens that you can then copy/paste into your application.

To use the CLI, you will need to install the Twilio CLI and log in to your Twilio account from the command line; see the CLI Quickstart for instructions. Then, you can install the Token CLI plugin with the following command:

twilio plugins:install @twilio-labs/plugin-token

To generate an Access Token, run the following command. --identity is a required argument and should be a string that represents the user identity for this Access Token.

twilio token:video --identity=<identity>

In a production application, your back-end server will need to generate an Access Token for every user in your application. Visit the User Identity and Access Token guide to learn more. You can find examples of how to generate an Access Token for a participant using Twilio's helper libraries in the User Identity and Acces Token guide.

Connect to a Room

Call TwilioVideo.connect() to connect to a Room from your iOS application. Once connected, you can send and receive audio and video streams with other Participants who are connected to the Room.

@IBAction func createARoom(sender: AnyObject) {
    let connectOptions = ConnectOptions(token: accessToken) { (builder) in
        builder.roomName = "my-room"
    }
    room = TwilioVideoSDK.connect(options: connectOptions, delegate: self)
}

// MARK: RoomDelegate

func roomDidConnect(room: Room) {
    print("Did connect to Room")

    if let localParticipant = room.localParticipant {
        print("Local identity \(localParticipant.identity)")

        // Set the delegate of the local particiant to receive callbacks
        localParticipant.delegate = self
    }
}

You must pass the Access Token when connecting to a Room. You may also optionally pass the following:

• Local audio, video or data tracks, to begin sharing pre-created local media with other Participants in the Room upon connecting.
• A room name, which allows you to dynamically specify the name of the Room you wish to join. (Note: You can also encode the Room name in the Access Token, which will allow the user to connect to only the Room specified in the token.)
• An ICE transport policy, which allows you to force calls through TURN relay for testing purposes.

The name of the Room specifies which Room you wish to join. If a Room by that name does not already exist, it will be created upon connection. If a Room by that name is already active, you'll be connected to the Room and receive notifications from any other Participants also connected to the same Room. Room names must be unique within an account.

You can also create a Room using the Rooms REST API. Look at the REST API Rooms resource docs for more details.

Example: Create a Room called DailyStandup

 curl -XPOST 'https://video.twilio.com/v1/Rooms' \
 -u '{API Key SID}:{API Secret}' \
 -d 'UniqueName=DailyStandup'

Note: If you don’t specify a Type attribute, then Twilio will create a Group Room by default.

Default Room Settings

You can also set the room type from the Room Settings page in the Twilio Video Console. Twilio will use the room type set on Room Settings page, when you create a room from the client-side or the REST API.

Note: Twilio will set the Room Type as Group by default on the Room Settings page.

Once a Room is created, Twilio will fire a room-created webhook event, if the StatusCallback URL is set. You can set the StatusCallback URL on the Room Settings page, if you want create a room from the client-side. If you create a room using the REST API, then you need to provide a StatusCallback URL while creating the room.

 curl -XPOST 'https://video.twilio.com/v1/Rooms' \
 -u '{API Key SID}:{API Secret}' \
 -d 'UniqueName=DailyStandup' \
 -d 'StatusCallback=https://hooks.yoursite.com/room-events' \
 -d 'StatusCallbackMethod=POST' \
 -d 'Type=group'

Enabling Room Recordings

Recordings can be enabled only on Group Rooms. Set Recordings to Enabled to record participants when they connect to a Group Room. Recordings can also be enabled on Group Rooms through via the Rest API at Room creation time by setting the RecordParticipantsOnConnect property to true.

curl -XPOST 'https://video.twilio.com/v1/Rooms' \
-u '{API Key SID}:{API Secret}' \
-d 'UniqueName=DailyStandup' \
-d 'Type=group' \
-d 'RecordParticipantsOnConnect=true' \
-d 'StatusCallback=http://example.org'

Join a Room

If you'd like to join a Room you know already exists, you handle that exactly the same way as creating a room: just pass the Room name to the connect method. Once in a Room, you'll receive a room:participantDidConnect: callback for each Participant that successfully joins. Querying the remoteParticipants getter will return any existing Participants who have already joined the Room.

@IBAction func joinRoom(sender: AnyObject) {
    let connectOptions = ConnectOptions(token: accessToken) { (builder) in
        builder.roomName = "existing-room"
    })
    room = TwilioVideoSDK.connect(options: connectOptions, delegate: self)
}

// MARK: RoomDelegate

func roomDidConnect(room: Room) {
    print("Did connect to room")

    if let localParticipant = room.localParticipant {
        print("Local identity \(localParticipant.identity)")

        // Set the delegate of the local particiant to receive callbacks
        localParticipant.delegate = self
    }
}

Set up local media

You can capture local media from your device's microphone, camera or screen-share on different platforms in the following ways:

In an iOS application, begin capturing audio data by creating a TVILocalAudioTrack, and begin capturing video by creating a TVILocalVideoTrack with an associated TVIVideoCapturer. The iOS Video SDK provides customizable video capturers for both camera and screen capture.

// Create an audio track
var localAudioTrack = LocalAudioTrack()

// Create a data track
var localDataTrack = LocalDataTrack()

// Create a CameraSource to provide content for the video track
var localVideoTrack : LocalVideoTrack?

// Create a video track with the capturer.
if let camera = CameraSource(delegate: self) {
    localVideoTrack = LocalVideoTrack(source: camera)
}

Specify tracks at connect time

When the client joins a Room, the client can specify which Tracks they wish to share with other Participants. Imagine we want to share the audio and video Tracks we created earlier.

let connectOptions = ConnectOptions(token: accessToken) { (builder) in
    builder.roomName = "my-room"

    if let audioTrack = localAudioTrack {
        builder.audioTracks = [ audioTrack ]
    }
    if let dataTrack = localDataTrack {
        builder.dataTracks = [ dataTrack ]
    }
    if let videoTrack = localVideoTrack {
        builder.videoTracks = [ videoTrack ]
    }
}

var room = TwilioVideoSDK.connect(options: connectOptions, delegate: self)

Connect as a publish-only Participant

For some use cases (such as a ReplayKit broadcast extension) you may wish to connect as a publish-only Participant that is not subscribed to any Tracks. If you are connecting to a Group Room, you may disable automatic subscription behavior via ConnectOptions.

let connectOptions = ConnectOptions(token: accessToken) { (builder) in
    builder.isAutomaticSubscriptionEnabled = false
    builder.roomName = "my-room"

    if let audioTrack = localAudioTrack {
        builder.audioTracks = [ audioTrack ]
    }
}

var room = TwilioVideo.connect(options: connectOptions, delegate: self)

Working with Remote Participants

Handle Connected Participants

When you join a Room, Participants may already be present. You can check for existing Participants in the roomDidConnect: callback by using the remoteParticipants getter. To receive RemoteParticipantDelegate callbacks you will need to set the RemoteParticipant.delegate property for each connected Remote Participant.

room = TwilioVideo.connect(options: connectOptions, delegate: self)

// MARK: RoomDelegate

func roomDidConnect(room: Room) {
    // The Local Participant
    if let localParticipant = room.localParticipant {
        print("Local identity \(localParticipant.identity)")

        // Set the delegate of the local participant to receive callbacks
        localParticipant.delegate = self
    }

    // Connected participants already in the room
    print("Number of connected Participants \(room.remoteParticipants.count)")

    // Set the delegate of the remote participants to receive callbacks
    for remoteParticipant in room.remoteParticipants {
      remoteParticipant.delegate = self
    }
}

func participantDidConnect(room: Room, participant: RemoteParticipant) {
    print ("Participant \(participant.identity) has joined Room \(room.name)")

    // Set the delegate of the remote participant to receive callbacks
    participant.delegate = self
}

func participantDidDisconnect(room: Room, participant: RemoteParticipant) {
    print ("Participant \(participant.identity) has left Room \(room.name)")
}

Handle Participant Connection Events

When Participants connect to or disconnect from a Room that you're connected to, you'll be notified via an event listener: Similar to Room Events, Twilio will fire Participant events if the StatusCallback webhook URL is set when the Room is created. These events help your application keep track of the participants who join or leave a Room.

// MARK: RoomDelegate

// First, we set a Participant Delegate when a Participant first connects:
func participantDidConnect(room: Room, participant: RemoteParticipant) {
    print("Participant connected: \(participant.identity)")
    participant.delegate = self
}

Display a Remote Participant's Video

To see the Video Tracks being sent by remote Participants, we need to render them to the screen:

// MARK: RemoteParticipantDelegate

/*
 * In the Participant Delegate, we can respond when the Participant adds a Video
 * Track by rendering it on screen.
 */
func didSubscribeToVideoTrack(videoTrack: RemoteVideoTrack,
                              publication: RemoteVideoTrackPublication,
                              participant: RemoteParticipant) {

    print("Participant \(participant.identity) added a video track.")

    if let remoteView = VideoView.init(frame: self.view.bounds,
                                       delegate:self) {

        videoTrack.addRenderer(remoteView)
        self.view.addSubview(remoteView)
        self.remoteView = remoteView
    }
}

// MARK: VideoViewDelegate

// Lastly, we can subscribe to important events on the VideoView
func videoViewDimensionsDidChange(view: VideoView, dimensions: CMVideoDimensions) {
    print("The dimensions of the video track changed to: \(dimensions.width)x\(dimensions.height)")
    self.view.setNeedsLayout()
}

Participating in a Room

Display a Camera Preview

Sometimes you need to make sure you're looking fantastic before entering a Room. We get it. The iOS SDK provides a means to render a local camera preview outside the context of an active Room:

// Use CameraSource to produce video from the device's front camera.

if let camera = CameraSource(delegate: self),
    let videoTrack = LocalVideoTrack(source: camera) {

    // VideoView is a VideoRenderer and can be added to any VideoTrack.
    let renderer = VideoView(frame: view.bounds)

if let camera = TVICameraCapturer(source: .frontCamera),
    let videoTrack = TVILocalVideoTrack(capturer: camera) {

    // TVIVideoView is a TVIVideoRenderer and can be added to any TVIVideoTrack.
    let renderer = TVIVideoView(frame: view.bounds)

    // Add renderer to the video track
    videoTrack.addRenderer(renderer)

    self.localVideoTrack = videoTrack
    self.camera = camera
    self.view.addSubview(renderer)
} else {
    print("Couldn't create CameraCapturer or LocalVideoTrack")
}

Disconnect from a Room

You can disconnect from a Room you're currently participating in. Other Participants will receive a participantDisconnected event.

// To disconnect from a Room, we call:
room?.disconnect()

// This results in a callback to RoomDelegate#roomDidDisconnect(room: Room, error: Error?)

// MARK: RoomDelegate

func roomDidDisconnect(room: Room, error: Error?) {
    print("Disconnected from room \(room.name)")
}

Room reconnection

The Video SDK will raise notifications when a Room is reconnecting due to a network disruption. A Room reconnection is triggered due to a signaling or media reconnection event. To capture when a reconnection is triggered or that it has reconnected:

// MARK: RoomDelegate

// Error will be either TwilioVideoSDK.Error.signalingConnectionError or TwilioVideoSDK.Error.mediaConnectionError
func roomIsReconnecting(room: Room, error: Error) {
    print("Reconnecting to room \(room.name), error = \(String(describing: error))")
}

func roomDidReconnect(room: Room) {
    print("Reconnected to room \(room.name)")
}

Reconnections in a Peer-to-Peer Room

In a Peer-to-Peer Room, each Participant has media connections to all the other Participants in the Room. If all media connections between the LocalParticipant and all other Participants are broken, then the LocalParticipant's Room will enter the reconnecting state until media connectivity with at least one Participant is re-established.

Reconnections and the UIApplication lifecycle

There are certain instances when an application is put into the background that both the signaling and media connection are closed, which will cause the reconnecting delegate method to be invoked:

• When connected to a Peer-to-Peer Room with no Remote Participants.
• When connected to a Peer-to-Peer Room with other Remote Participants and no shared audio tracks.
• When connected to a Group Room with no shared audio tracks.

Server-side control

The Programmable Video REST API allows you to control your video applications from your back-end server via HTTP requests. To learn more check out the Programmable Video REST API docs.

Getting help

We love feedback and questions especially those with helpful debugging information so we can diagnose and respond quickly. When submitting issues or support tickets, it would be great if you add the following:

• Description - A description of the issue
• Steps to reproduce - List the steps necessary to reproduce the issue
• Code - Include any applicable code snippets that would assist in reproduction and troubleshooting
• Expected Behavior - What you expect to happen
• Actual Behavior - What actually happens
• Reproduces How Often - What percentage of the time does it reproduce?
• Logs - Any log output when the issue occurs. See below for enabling debug level logging.
• Video iOS SDK - The version(s) of the Video iOS SDK where this issue is apparent
• Xcode - The version(s) of Xcode where this issue is apparent
• iOS Version - The version(s) of iOS where this issue is apparent
• iOS Device - The iOS device(s) where this issue is apparent
• Room SID - Room SIDs can be useful for tracing backend issues

After gathering the above information, you can get help in a few ways:

For issues related to the Twilio Video iOS SDK itself:

• Twilio Video iOS SDK on Github
• Twilio Support

For issues related to the Twilio Video iOS Quickstarts:

• Video iOS Quickstart on GitHub

Enabling Debug Logging

To enable debug level logging, add the following code in your application:

TwilioVideoSDK.setLogLevel(.debug)