Key concepts

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SDK, Stream publishing & playing, Room

• ZEGO Express SDK: the real-time Audio and Video Call SDK provided by ZEGOCLOUD. It can help you provide audio and video services that feature convenient access, high-definition and fluency, cross-platform communication, low latency, and high concurrency.
• Stream publishing: the process of publishing the audio and video data streams that are captured and packaged to ZEGOCLOUD real-time audio and video cloud.
• Stream playing: the process of receiving and playing audio and video data streams from ZEGOCLOUD real-time audio and video cloud.
• Room: the service provided by ZEGOCLOUD for organizing user groups and allowing users in the same room to receive and send real-time audio, video, and messages to each other.
  1. Users can publish or play streams only after logging in to a room.
  2. Users can receive notifications about changes (such as users joining or leaving a room, and audio and video stream changes) in the room where they are in.

Signaling

Signaling is a protocol or message to manage communication and connections in networks. ZEGOCLOUD packages all signaling capabilities into a SDK, providing you with a readily available real-time signaling API.

Token

Token: To avoid unauthorized service access or operations, ZEGOCLOUD uses digital Tokens to verify user identity, control and validate user privileges. You will need to pass a Token when you log in to a room.

Currently, ZEGOCLOUD supports validating the following:

• User identity: check users' identity by validating the Token.
• User privileges:
  • Room login privilege: check users' privilege to log in to a room by validating the room ID contained in the Token.
  • Stream publishing privilege: check users' privilege to publish streams in a room by validating the ID of the published stream contained in the Token.

To improve business security, we recommend you enable the room login and stream publishing privilege validation for all scenarios. In particular:

• In cases where your app provides different types of rooms dedicated to different users, such as general rooms and member-only rooms, it is necessary to validate a user's privilege to enter a room.
• In a voice chat room, it is necessary to prevent users who are not on the speaker seats from speaking in the room.
• In voice games such as Werewolf, it is necessary to prevent the scenario that when the app is hacked, the hacker can use different user IDs to log in to the same room to cheat in the game.

Stream-Mixing

Through the stream-mixing service, multiple published media streams can compose a single stream , which allows audiences to play just one stream to improve quality and reduce performance cost.

SEI (Supplemental Enhancement Information)

• For a detailed explanation of the SEI feature, refer to Convey extra information using SEI.

• Additional information about SEI and stream mixing: The mixing server will re-encode the SEI of all input streams into the output mixed stream. Therefore, the SEI information sent by the host can be received by the audience in both rooms and the other host.

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For more concepts, see Glossary.