StreamLive Pro

Live streaming glossary: the terms you will meet

A live streaming glossary in plain words: stream key, RTMP, SRT, bitrate, multistream, Preview and Program, ISO, captions, reframe. Where each shows up in StreamLive Pro.

Updated November 5, 2026 · 6 min read

Live streaming has its own vocabulary, and some words mean two things (SRT is both a streaming protocol and a caption file). Below, each term gets a short definition and, where it applies, the place you meet it in StreamLive Pro. Terms are grouped by the stage of a broadcast: sending the picture, the studio, after the broadcast.

Sending the picture

Multistream

One broadcast sent to several destinations at once, for example YouTube, a Facebook Page and Instagram. In StreamLive Pro your computer sends one stream and the copies are made on our servers, so your upload does not grow with each destination. How many destinations at once depends on the plan. See /multistream?lang=en.

Destination

A place a broadcast goes: a YouTube channel, a Facebook Page, an Instagram account, or any server that accepts RTMP, RTMPS or SRT. You add them in Connections.

Stream key

A secret code that tells a network which account the stream belongs to. Some networks give a fixed key (an X Producer source, for example, keeps its key); Instagram and TikTok give a new key for each session, so you paste a fresh one before every live. Anyone with your key can stream to your account. More: RTMP and stream keys: where to find them, what breaks.

RTMP and RTMPS

RTMP is the long-standing protocol for sending a live stream from an encoder to a server. RTMPS is the same over an encrypted connection. Most networks take one of them.

SRT (protocol)

Secure Reliable Transport, a newer protocol built to recover from lost packets on poor connections. StreamLive Pro accepts SRT from an encoder and can send to an SRT destination. Not to be confused with SRT the caption file below. Comparison: RTMP vs RTMPS vs SRT.

WHIP

A newer way to send a live stream over WebRTC. StreamLive Pro accepts it from encoders as a beta option. It is not offered as a destination.

Ingest

The address a stream is sent to. In StreamLive Pro, external software such as OBS or vMix sends to our ingest address with a key, on the paid plans; the trial uses the browser studio only.

Encoder

The software or device that turns your cameras and microphones into a stream: OBS, vMix, a hardware box, or the browser studio itself. See Streaming from OBS or vMix with RTMP.

Bitrate

How much data the stream sends per second. Higher bitrate means a sharper picture and needs more upload speed. Each network publishes its own recommended settings. The arithmetic for several destinations is in Upload speed and bitrate for multistreaming.

Resolution and frame rate

Resolution is the size of the picture in pixels (1920 x 1080 is called 1080p). Frame rate is how many pictures per second (30 or 60 are common). Both raise the bitrate you need.

Latency

The delay between something happening in front of the camera and viewers seeing it. Every hop (encoder, our servers, the network, the viewer's player) adds some.

In the studio

Preview and Program

Program is what viewers see now. Preview is the next shot, prepared out of sight. You set up the next camera or layout in Preview, then send it to Program. See Preview and Program explained.

Take

The action that swaps Preview into Program.

Overlay

A graphic on top of the picture: a logo, a frame, a lower third. The browser studio has 8 overlay channels above Program.

Lower third

A caption in the lower part of the screen with a name and a title. See How to make lower thirds for a live stream.

Ticker

A line of text that scrolls along the bottom of the screen, for headlines or announcements.

Chroma key (green screen)

Replacing a green or blue background with another picture. See How to set up a green screen virtual studio for live streams.

Mix-minus

A sound feed for a remote guest that contains everything except their own voice, so they do not hear themselves with a delay and cause echo.

Guest link

A link that lets a remote guest join the studio from a browser. In StreamLive Pro one link serves all guests and is valid for 4 hours. See Guests and invitations — bringing people into the room.

ISO recording

A separate recording of each camera, besides the mixed program, so you can re-edit later. In the browser it is available in the podcast studio for cameras connected to the computer. See How to record each camera separately (ISO recording).

Safe frame

Guides on screen that show what will be visible after a 9:16 or 1:1 crop, so you keep faces and text inside.

Pre-recorded broadcast

A prepared video sent out as a live broadcast at a set time. Available on the trial, Pro and Studio; not on Creator.

Scheduled broadcast

A live set up in advance for a date and time, optionally announced on YouTube and Facebook beforehand. See Schedule a live broadcast in advance.

After the broadcast

Recording

The saved video of the broadcast. In StreamLive Pro it is kept only if you press Record; otherwise the temporary copy is removed about 2 hours after the broadcast. See Recordings and storage — what is kept and for how long.

VOD

Video on demand: the recording people watch after the live is over.

Shorts, Reels, vertical clips

Short vertical videos for YouTube Shorts, Instagram Reels and TikTok. StreamLive Pro cuts up to 5 from a broadcast or an uploaded video, with captions. See How to create Shorts from any video, no live stream needed.

Reframe

Cropping a horizontal picture to vertical while keeping the speaker inside the frame. See Turn a horizontal video into vertical.

Transcription

Turning speech into text, in the same language. See Transcribe a live stream.

Captions and subtitles

Text of the speech on screen. Burned-in captions are part of the picture; a caption file sits beside the video and viewers can switch it off.

SRT, VTT and ASS (caption files)

SRT and VTT are plain caption files with text and times. ASS also carries the design. See Export captions as SRT, VTT or ASS.

Translation and dubbing

Translation here means captions in another language, with the original voice kept. Dubbing replaces the voice with another language; StreamLive Pro does not dub.

Right-to-left mark (RLM)

An invisible character that tells a player a line runs right to left. It keeps punctuation at the end of a Hebrew or Arabic line on the correct side. See Automatic Hebrew captions for Premiere Pro, step by step.

Terms that are easy to confuse

Frequently asked questions

What is the difference between streaming and multistreaming?

Streaming sends a broadcast to one destination. Multistreaming sends the same broadcast to several destinations at once, which StreamLive Pro does on its servers from your one stream.

Is a stream key the same as a password?

It works like one for streaming: whoever has it can stream to your account. Keep it private and replace it if it leaks.

What does SRT mean in live streaming?

In streaming, SRT is Secure Reliable Transport, a protocol for sending video over unreliable connections. In captions, SRT is a SubRip caption file. They are unrelated.

What is mix-minus?

A sound feed for a remote guest with everything except their own voice, which prevents echo.

Do I need to know these terms to go live with StreamLive Pro?

No. The browser studio handles the encoder, the keys of networks you sign into, and the fan-out. The terms help when something needs fixing.

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