# Glossary (/en/realtime-media/rtmp-gateway/reference/glossary)

> For AI agents: see the complete documentation index at [llms.txt](/llms.txt).

## A

### Agora Console

Agora Console is the site where developers manage Agora projects and services.

### App ID

An App ID is a randomly generated string provided by Agora and is the unique identifier of an app.

### App certificate

An App certificate is a randomly generated string provided by Agora for enabling token authentication.

### Audio mixing

Audio mixing means combining multiple audio streams into one.

## C

### Channel

A channel is a way of grouping users together and is identified by a unique channel name.

### Channel profile

The channel profile is a configuration that Agora uses to apply optimized algorithms for different real-time use cases.

### Cloud proxy

Cloud proxy is a proxy service that enables users to connect to Agora services through a firewall by using fixed IP addresses.

## D

### Delay

In real-time audio and video communication, delay refers to the time elapsed from when data is sent to when it is received.

### Dual-stream mode

In dual-stream mode, the RTC SDK simultaneously transmits a higher-resolution video stream along with an additional low-resolution, low-bitrate video stream.

## H

### Host

The host is a user who has streaming permissions in a channel.

## J

### Jitter

In real-time audio and video communication, jitter is the variation in the delay of data packets transmitted continuously on the network.

## L

### Last mile

The last mile refers to the network between the Agora edge server and the end user's device.

### Low-quality video stream

In dual-stream mode, the SDK transmits two video streams of differing quality at the same time.

## M

### Media stream

A media stream is an object that contains media data.

### Media Push

Media Push enables you to upload audio and video streams from Agora channels to a CDN to reach a larger audience.

## P

### Packet loss

Packet loss refers to data packets transmitted on the network failing to arrive at their intended destination.

### Publish

Publishing is the act of sending a user's audio or video data to the channel.

## S

### SDRTN(R)

SDRTN(R) is Agora's globally distributed Software-Defined Real-Time Network.

### Stream

A stream is a sequence of digitally encoded coherent signals that contains audio or video data.

### Subscribe

Subscribing is the act of receiving media streams published by remote users.

## T

### Token

A token, also known as a dynamic key, is used for authentication when an app user joins a channel or logs in to Agora Signaling.

### Transcoding

Transcoding is the process of decoding audio and video data and then re-encoding them into the target conversion output or format.

## U

### User ID (UID)

In the Agora RTC SDK, a user ID identifies a user in the channel.

### User role

The type of user role determines whether the user in the channel has streaming permissions.

## V

### Video layout

Video layout arranges the display of users when multiple users are mixed into one stream, such as in Media Push or composite recording.

### Video mixing

Video mixing means combining multiple video streams into one.

### Video profile

The video profile refers to a set of video attributes, such as resolution, bitrate, and frame rate.

### RTC SDK

The RTC SDK is an SDK developed by Agora to enable developers to add real-time video and audio interaction to their projects.

### Voice SDK

The Voice SDK enables real-time audio communication.

## W

### Web page recording mode

In web page recording mode, the content and audio of a specified web page are recorded in a single file.