Live Streaming Glossary: RTMP, Bitrate, Keyframe and More

How to use this glossary

This glossary defines the terms you meet when you go live from a computer, set up OBS Studio or send one stream to several platforms. Each entry is short, uses only what the specifications and platform pages cited below say, and links to the guide that goes deeper. Platform figures are dated as of October 5, 2026. Terms are listed alphabetically; the guides for going live are in go live from a PC, and the settings in best OBS settings for streaming.

Terms starting with A

Adaptive bitrate (ABR)

Delivering several versions of the same video at different bitrates so the player can switch to suit the viewer's connection. In HLS a Master Playlist lists the versions and clients should switch between them as network conditions change (RFC 8216). Read more: What is HLS?.

Audio bitrate

The data used by the sound, separate from the video. The platforms we cover list figures around 128 kbps stereo (YouTube, Facebook, LinkedIn), while Twitch recommends 96 kbps with 160 kbps as its maximum. Read more: What is bitrate?.

Terms starting with B

Base and output resolution

OBS Studio terms. The base (canvas) resolution is the size of your scene; the output (scaled) resolution is the size sent to viewers. Lowering output resolution is a first step when encoding is overloaded. Read more: Best OBS settings.

Bitrate

How much data a stream uses each second, usually in kbps or Mbps. Higher bitrates need more upload bandwidth, and the total cannot exceed it. Read more: What is bitrate?.

Terms starting with C

CBR (constant bitrate)

A rate-control mode that keeps the bitrate steady. YouTube, Facebook and Kick state a preference for it, Twitch suggests all broadcasters use it and Kick says VBR is not supported. VBR (variable bitrate) lets the rate change with the picture. Read more: What is bitrate?.

Codec

The method used to compress video or audio. The platforms we cover list H.264 for video and AAC for audio; YouTube also lists H.265 and AV1 for video. Read more: Best OBS settings.

Custom RTMP

A destination type in which you enter a server URL and stream key yourself instead of choosing a named service. Facebook's instructions use Custom Streaming Server or RTMP Server, and Instagram's Live Producer uses Custom RTMP. Read more: What is RTMP?.

Terms starting with D

Dropped frames

Frames your encoder could not send. The OBS Project says it means your connection to the server is not stable or you cannot keep up with your set bitrate; too many can disconnect you. Read more: Best OBS settings.

Terms starting with E

Edge node

An ingest location near you. Multistream Platform has edge nodes in US East, US West, EU Central, Tokyo and São Paulo. Read more: See features.

Encoder

Software or hardware that converts your camera and screen into compressed video for streaming. YouTube describes an encoder as converting your video into a digital format to stream; OBS Studio is one. Read more: Multistream with OBS Studio.

Encoding overloaded

An OBS Studio warning that your computer cannot encode fast enough. The OBS Project suggests lowering the output resolution or frame rate, simplifying scenes and closing other GPU-heavy programs. Read more: Best OBS settings.

Terms starting with F

Frame rate (fps)

How many pictures per second the video shows. Platforms list bitrates separately for 30 and 60 fps because 60 fps needs more data. Read more: What is bitrate?.

Terms starting with H

HLS

HTTP Live Streaming: video cut into short segments that a playlist lists, delivered over ordinary web servers. Documented in RFC 8216. Read more: What is HLS?.

Terms starting with I

Ingest

The server that receives your stream from your encoder, usually over RTMP or SRT. Delivery to viewers is a separate step. Read more: What is RTMP?.

Terms starting with K

Keyframe

A fully encoded frame that later frames refer to. A player can start playing at a keyframe. Read more: Keyframe interval.

Keyframe interval

The time between keyframes. YouTube and Facebook recommend 2 seconds and say not to exceed 4 seconds; Twitch, Kick and LinkedIn list 2 seconds. Read more: Keyframe interval.

Terms starting with L

Live Control Room

YouTube Studio's page for managing a stream. With an encoder you copy the stream URL and key from its Stream tab, and you click Go live there after checking the preview. Read more: Go live on YouTube from a PC.

Live Producer

Instagram's browser tool for going live from streaming software on instagram.com. Instagram's post describes it as limited access. Read more: Go live on Instagram from a PC.

Terms starting with M

M3U8

The text playlist file HLS players read; it lists segments or other playlists. Read more: What is an M3U8 file?.

Media segment

One short piece of an HLS stream. A Media Playlist lists the segments of one version of the video, in order. Read more: What is HLS?.

Multichat

Reading chat from several platforms in one place. It is a Multistream Platform feature. Read more: See features.

Multistreaming

Broadcasting the same live video to several platforms at once, either from several outputs on your computer or through a relay. Read more: What is multistreaming?.

Terms starting with P

Persistent stream key

A Facebook option in Advanced Settings that lets you reuse a stream key. Facebook says you can only have one live video at a time with it. Read more: Facebook stream key.

Terms starting with R

Relay

A service that takes one incoming stream and delivers copies to many destinations, so your computer uploads one stream. Read more: What is multistreaming?.

RTMP and RTMPS

Real-Time Messaging Protocol, widely used to send a stream from an encoder to a server. RTMPS is RTMP over TLS, which adds encryption; YouTube recommends it. Read more: What is RTMP?.

Terms starting with S

Simulcasting

Another word for sending the same stream to more than one platform. Some platforms publish rules about it; read them first. Read more: What is simulcasting?.

SRT

Secure Reliable Transport, a protocol designed to recover from packet loss. Multistream Platform accepts it alongside RTMP. Read more: RTMP vs SRT.

Stream key

A private code that tells a platform which channel your encoder is streaming to. Anyone who has it can stream to your channel, so keep it secret. Read more: What is a stream key?.

Terms starting with T

TikTok LIVE Studio

TikTok's own streaming software for Windows and macOS. It needs LIVE access. Read more: TikTok without a stream key.

Terms starting with U

Upload headroom

Spare upload capacity. YouTube recommends leaving about 20%, and the OBS Project suggests starting at 75% of your upload speed. Read more: Bandwidth requirements.

Terms starting with V

VOD (video on demand)

A recording viewers can watch later. On Twitch, OBS Studio can send a different audio track to the VOD than to the live stream. Read more: Twitch with OBS.

Tools that use these terms

Put the terms to work with the free streaming bitrate recommender, the RTMP URL and stream key helper and the multistream bandwidth calculator. If you want to stream to several platforms from one upload, see features and pricing; the free Starter plan costs $0 per month.

Sources

• RFC 8216: HTTP Live Streaming (R. Pantos and W. May, August 2017; Informational)
• Adobe RTMP Specification 1.0 (H. Parmar and M. Thornburgh, December 2012)
• YouTube Help: Choose live encoder settings, bitrates, and resolutions
• Twitch Help: Broadcasting Guidelines
• Facebook Help Centre: Time limit and guidelines for live streaming on Facebook
• Instagram: Live Producer (published November 2, 2022)
• OBS Project: Quick Start Guide (page dated 2021-08-25)
• OBS Project knowledge base: Stream Connection Troubleshooting (page dated 2024-09-30; cited by name, the OBS Project asks people not to link to knowledge base pages)

Platform figures were checked on October 5, 2026. Platforms change their recommendations, so confirm against the current documentation before you go live.