Conference Capacity

The Dolby.io Communications APIs conferencing infrastructure supports large conferences while maintaining high audio and video quality.

Supported number of participants

The platform supports a specific number of streams in a conference, which impacts the number of participants who can join conferences without degrading audio and video quality. There are two types of participants: users who join conferences using the join method and listeners who join conferences using the listen method. Users can send and receive streams whereas listeners can only receive streams. The ratio of users to listeners impacts the number of participants who can join a conference. Additionally, audio-only conferences support more participants than regular conferences where participants can share audio and video.

Maximum number of users

The supported number of users in a conference depends on the conference type and the audio codec used. In audio-only conferences, the platform supports up to 250 users when using the DVC codec and up to 50 users in the case of Opus. In conferences in which participants can share audio and video, the platform supports up to 50 users.

CodecShared mediaMaximum number of users
DVCAudio *250
OpusAudio *50
Opus / DVCAudio and video50

* To create an audio-only conference, set the audioOnly parameter to true while creating a conference. Otherwise, the video capacity limits are applied.

Maximum number of listeners

The maximum number of listeners who may join a conference depends on the type of listeners. The platform supports up to 60,000 mixed listeners. The number of supported regular listeners depends on the number of users and the conference type. In audio-only conferences with up to 4 users, the platform supports up to 10,000 regular listeners. In conferences in which users share audio and video, the maximum number of regular listeners depends on the number of users. In conferences with up to 10 users, the platform supports 5,000 regular listeners divided by the number of users.

Listener typeNumber of usersShared mediaMaximum number of listeners
Mixed-Audio and video60,000
Regular1 - 4Audio *10,000
Regular1 - 10Audio and video5,000 / Number of users
Regular11 - 50Audio and video120

* To create an audio-only conference, set the audioOnly parameter to true while creating a conference. Otherwise, the video capacity limits are applied.

To handle large webinars, listeners receive the participantAdded and participantUpdated events only about users; they do not receive these events for other listeners. Users receive the events about other users and do not receive any events about listeners. To notify all participants about the number of participants in a conference, you can use the activeParticipants events.

Maximum number of video streams

The platform supports receiving up to 49 video streams, so participants can receive video streams from all users. To receive video streams from fewer users or choose users whose video streams you want to continuously receive, you can use our Video Forwarding API.

Overload prevention

Overloading conferences may decrease audio and video quality and result in a poor experience. To avoid such behavior, the platform uses a capacity limit mechanism that impacts stream distribution. When a conference capacity reaches the limit, the mechanism does not allow additional participants to join the conference and returns a capacity limit error. It is not possible to create conferences that exceed the limit.

Conference streaming

Dolby.io conferences can be streamed to up to 60,000 viewers using the sub-second latency technology provided by Dolby.io Real-time Streaming (formerly Millicast WebRTC streaming services) and the Real-time Streaming REST APIs.