# Glossary — Live

Understand Live frame data, keyframes, and messaging terms used in co-viewing.

Canonical: https://developer.realsee.ai/docs/live/preparation/terminology
Source: https://developer.realsee.ai/docs/live/preparation/terminology.md
Language: en

## Frame Data (Keyframe)

The set of state data that the UI needs to keep in sync across screens during interaction.


> **info**

It is usually expressed as key-value pairs—the key is the name of a UI module, and the value is that module's state information.
For example, the frame data `{"popupPanel": { hidden: true }}` indicates that the UI interaction includes a popup panel, which we name `popupPanel`. It has a `hidden` state, and `true` means it is currently hidden.

## Snapshot

The set of **all frame data** at a given moment.


> **tip**

You can think of **frame data** as a subset of a **snapshot**. The "snapshot" information at a given moment lets you restore the entire UI state of that moment.

## RTC

Real-Time Communication. In this document it refers to the optional real-time audio capability used alongside the WebSocket co-viewing channel.


> **caution**

`@realsee/live@0.7.6` includes browser TRTC, browser Chime, and VR WebView RTC implementations. You can also provide a custom implementation of `RTCProtocol`. For configuration and peer dependencies, see [RTC and Environment](https://developer.realsee.ai/docs/live/rtc-and-environment).