Call glossary

Application

After you register for a Nexconn Console account, you can create applications for your calling business. Each application has separate Development and Production environments, with different App Keys and isolated data.

If your business includes multiple client roles, you can use the same App Key with multiple application identifiers to create multiple final applications.

User

Your app server provides a user ID (userId) to Nexconn and exchanges it for a Token. This step is completed by calling the IM Server API Get Token endpoint.

Users must hold a valid Token to connect to Nexconn through the IM SDK and use calling-related services.

Room

A room is a virtual space for 2 or more users to conduct audio/video sessions via Call SDK. Users in the same room can send and receive real-time audio/video media streams to/from each other.

• Rooms don't support direct creation. Nexconn creates the room internally when the first user joins.
• Depending on the client request, Nexconn can create a calling room, conference room, or live streaming room.
• A user can only be in one audio/video room at a time. To enter another room, they must exit the previous room.
• For mobile network and device constraints, we recommend no more than 16 video participants or 32 audio-only participants in a room.

RoomID

RoomID (room number / room ID) identifies a room, maintaining uniqueness at any given moment. RoomIds can be reused.

CallID

When using Call SDK, the SDK creates and manages the underlying audio/video room as part of the calling flow. CallID is the unique identifier for a call.

In a calling scenario, when the caller joins first, the SDK creates the room and the room ID is the same as the CallID. The callee then uses the CallID to join the same room.

Session

When using Call SDK, a session represents the lifecycle of the current call or room activity.

SessionID

SessionID is the unique server-side identifier for a session. Nexconn generates it when the first user enters the room, and the session ends when everyone leaves the room or the server determines that all users are offline.

You can use SessionID for backend queries, troubleshooting, and communication with Nexconn support.

Publish

RTC SDK sends collected audio/video data to Nexconn audio/video servers according to negotiated methods. Publishing allows defining parameters like audio/video bitrate.

Subscribe

The process of RTC SDK retrieving audio/video data from Nexconn audio/video streams according to parameters.

Push stream

Two types: 1. Using RTC SDK in live streaming scenarios, pushing stream equals publishing audio/video resources; 2. Nexconn audio/video servers transmitting audio/video streams to Nexconn audio/video servers / third-party CDNs.

Pull stream

Two types: 1. Using RTC SDK to subscribe to audio/video resources; 2. When using third-party CDNs, pulling RTMP streams.

StreamID

A client can publish multiple audio/video streams, distinguished by StreamID. Typically used with SessionID to uniquely identify a stream.

LiveURL

After publishing audio/video resources, the service generates and returns a LiveURL to clients for audience subscription to watch (or listen to) corresponding live video content (or audio content).

Main stream

A video stream category referring to the stream with larger resolution when main-sub stream functionality is enabled. When enabled, the video encoder outputs two streams for the same video.

Sub stream

A video stream category referring to the stream with smaller resolution when main-sub stream functionality is enabled. When enabled, the video encoder outputs two streams for the same video.

Bypass push

In live streaming scenarios, Nexconn audio/video service can convert RTC media streams published by Nexconn audio/video SDK into standard live streaming RTMP protocol. Nexconn service can push RTMP streams to third-party CDNs, then distribute via CDN for CDN live streaming viewing.

Stream mixing

In live streaming scenarios, Nexconn audio/video service can merge multiple audio streams (or video streams) published by multiple people in a room into one audio stream (or video stream), with the generated stream identified by LiveURL.

Custom layout

One stream mixing layout mode. By calling the custom layout interface, you can set the overall size of mixed stream video and the position and size of each co-anchor's view.

Floating layout

One stream mixing layout mode. In this mode, one video stream serves as the base, with other video windows stacked on top of this base in sequence.

Adaptive layout

One stream mixing layout mode. In this mode, all audio/video streams in the room share the canvas equally using the same size and aspect ratio.

Host

In live streaming mode, people publishing media resources in the room. A pure audio live room supports up to 32 hosts, a pure video live room supports up to 16 hosts.

Audience

In live streaming mode, people subscribing to live room audio/video streams. Audience cannot publish resources.

Co-anchoring

Two types: 1. Co-anchoring within the same live room, specifically upgrading audience to host during livestream; 2. Co-anchoring between different rooms, also known as cross-room co-anchoring.

Participant

In conference mode, people who can publish resources in the room.

Observer

In conference mode, people who can only subscribe to audio/video streams published by participants.

Audio/Video signaling messages

Audio/video signaling messages are messages Nexconn uses to implement SDK business functions. Developers don't need to handle them. Instant messaging service's Full Message Routing data includes these message types. Message Callback service supports configuring these message types.

See Audio/Video Signaling Messages for specific signaling message list.

Call SDK

Call SDK is Nexconn's audio and video calling SDK. It provides an independent Call Server service and encapsulates the full calling flow, including dialing, ringing, answering, and hanging up, so developers can quickly build one-to-one and multi-party calling capabilities.