Using the Amazon Chime SDK - Amazon Chime

Using the Amazon Chime SDK

You use the Amazon Chime SDK to build real-time media applications that can send and receive audio and video and allow content sharing. The Amazon Chime SDK works independently of any Amazon Chime administrator accounts, and it does not affect meetings hosted on Amazon Chime. Instead, the Amazon Chime SDK provides builder tools that you use to build your own meeting applications.

Amazon Chime SDK prerequisites

Using the Amazon Chime SDK requires the following:

  • The ability to program.

  • An AWS account.

  • An IAM role with a policy that grants permission to access Amazon Chime API actions used by the Amazon Chime SDK, such as the AWS managed AmazonChimeSDK policy. For more information, see How Amazon Chime works with IAM and Allow users to access Amazon Chime SDK actions in the Amazon Chime Administrator Guide.

  • For the majority of use cases, you also need the following:

    • A server application – Manages meeting and attendee resources, and serves those resources to the client application. The server application is created in the AWS account and must have access to the IAM role mentioned previously.

    • A client application – Receives meeting and attendee information from the server application, and uses that information to make media connections.

Amazon Chime SDK concepts

The following terminology and concepts are central to understanding how to use the Amazon Chime SDK.

meeting

An ephemeral resource identified by a unique MeetingId. The MeetingId is placed onto a group of media services that host the active meeting.

media service group

The group of media services that hosts an active meeting.

media placement

A set of regionalized URLs that represents a media service group. Attendees connect to the media service group with their clients to send and receive real-time audio and video, and share their screens.

attendee

A meeting participant that is identified by a unique AttendeeId. Attendees may freely join and leave meetings using a client application built with an Amazon Chime SDK client library.

join token

A unique token assigned to each attendee. Attendees use the join token to authenticate with the media service group.

Amazon Chime SDK architecture

The following list describes how the different components of the Amazon Chime SDK architecture work together to support meetings and attendees, audio, video, and content sharing.

Meetings and attendees

When the server application creates a meeting using the Amazon Chime SDK, the meeting is assigned to a region-specific media service group. The hosts in this group are responsible for securely transferring real-time media between attendee clients. Each created attendee is assigned a unique join token, an opaque secret key that your server application must securely transfer to the client authorized to join the meeting on behalf of an attendee. Each client uses a join token to authenticate with the media service group. Clients use a combination of secure WebSockets and Datagram Transport Layer Security (DTLS) to securely signal the media service group, and to send and receive media to and from other attendees through the media service group.

Audio

The media service group mixes audio together from each attendee and sends the mix to each recipient, after subtracting their own audio from the mix. The Amazon Chime SDK for JavaScript samples audio at the highest sample rate supported by the device and browser, up to a maximum of 48kHz. Audio is encoded using the Opus codec, with a default bitrate of 32kbps, which can be increased to up to 64kbps. The Amazon Chime SDKs for iOS and Android sample audio at a rate of 16kHz and encodes using the Opus codec at 32kbps.

Video

The media service group acts as a Selective Forwarding Unit (SFU) using a publish and subscribe model. Each attendee can publish one video source, up to a total of 25 simultaneous videos per meeting. The Amazon Chime SDK for JavaScript supports video resolutions up to 1280x720 at 30 frames per second without simulcast, and 15 frames per second with simulcast. The Amazon Chime SDK for iOS and Android support video resolutions up to 1280x720 and 15 frames per second, however the actual framerate and resolution is automatically managed by the Amazon Chime SDK.

When active, video simulcast sends each video stream in two different resolutions and bitrates. Clients which are bandwidth constrained automatically subscribe to the lower bitrate stream. Video encoding and decoding uses hardware acceleration where available to improve performance.

Data messages

In addition to audio and video content, meeting attendees can send each other real-time data messages of up to 2 KB each. Developers can use messages to implement custom meeting features such as whiteboarding, chat, real-time emoji reactions, and application-specific floor control signaling.

Content sharing

The client application can share audio and video content, such as screen captures or media files. Content sharing supports pre-recorded content video up to 1280x720 at 15 frames per second, and audio up to 48kHz at 64kbps. Screen capture for content sharing is supported up to 15 frames per second, but may be limited by the capabilities of the device and browser.

Amazon Chime SDK quotas

Resource Quota Adjustable

Active Meetings

250

Yes

Attendees per meeting

250

No

Audio streams per meeting

250

No

Video tiles per meeting

25

Yes

Content shares per meeting

2

No

API Rate

10 requests per second (RPS) with a burst of 20 RPS.

Yes

Amazon Chime SDK system requirements

The following system requirements apply to applications created with the Amazon Chime SDK.

Supported browsers, Amazon Chime SDK for JavaScript

Operating system

Browser

Supported versions

Notes

Windows

Mozilla Firefox

75 and later

Google Chrome

78 and later

Chromium-based Edge

79 and later
Chromium-based Electron 7 and later With Chrome version 78 and later.
Opera 66 and later

macOS

Mozilla Firefox

75 and later

Google Chrome

78 and later

Chromium-based Edge

79 and later

Chromium-based Electron

Safari 12 and later
Opera 66 and later
iOS Mozilla Firefox 10.0 and later Audio and video only, no content sharing.
Google Chrome 10.0 and later Audio and video only, no content sharing.
Safari 12.0 and later Audio and video only, no content sharing.
WKWebView 14.3 and later Audio and video only, no content sharing.
Android Google Chrome 10.0 and later Audio and video only, no content sharing.
Samsung 12 and later Audio and video only, no content sharing.
Chromium WebView 5.0 and later Audio and video only, no content sharing.
Ubuntu LTS 16.04 and later Google Chrome 78 and later

Amazon Chime SDK for iOS

  • iOS version 10.0 and later

Amazon Chime SDK for Android

  • Android OS version 5.0 and later, ARM and ARM64 architecture