Streaming Glossary: 60+ Terms Explained in Plain English
Bitrate, HDR10+, eARC, AV1, FAST, SVOD… every streaming term you're likely to meet, explained in one or two clear sentences and grouped by topic.
Streaming comes with a lot of jargon. Settings menus, product boxes and help pages throw around terms like bitrate, HDR10+ and eARC as if everyone knows them.
This streaming glossary explains the terms you’re most likely to meet, in plain English. They’re grouped by topic so you can jump to what you need. For the bigger picture of how all these pieces fit together, start with how video streaming works.
Delivery and connection terms
Bandwidth — The maximum amount of data your connection can carry at once, usually in megabits per second (Mbps). Think of it as the width of a pipe.
Mbps (megabits per second) — The unit used for internet speed and video bitrate. Not to be confused with MB/s (megabytes per second), which is eight times larger.
Latency — How long data takes to make a round trip, measured in milliseconds (ms). Low latency matters most for live streams and gaming.
Jitter — How much latency varies from moment to moment. High jitter can cause stutter even on a fast connection.
Packet loss — When small pieces of data never arrive and must be re-sent. Even a little packet loss can trigger buffering.
CDN (content delivery network) — A network of servers spread across many locations that store copies of video close to viewers, so streams start quickly and run smoothly.
DNS (domain name system) — The internet’s address book, turning names like a service’s website into server addresses. A slow DNS server can make apps slower to start.
Router — The box that shares your internet connection between devices, by cable or Wi-Fi.
Mesh Wi-Fi — A system of several Wi-Fi units working together to cover a larger home evenly.
Ethernet — A wired network connection. Usually faster and more stable than Wi-Fi.
Throttling — When a network deliberately slows certain traffic. Some mobile plans limit video quality this way.
Playback terms
Buffer — A short queue of video your player downloads ahead of what you’re watching, so small slowdowns don’t interrupt playback.
Buffering — What happens when the buffer runs empty and playback pauses until more data arrives.
Adaptive bitrate (ABR) — The technique players use to switch quality up or down automatically depending on your connection. See adaptive bitrate streaming explained.
Manifest — A small file listing all available versions and chunks of a video, which the player reads first.
Chunk / segment — A small piece of video, typically a few seconds long. Streams are delivered as a series of chunks.
Start-up time — How long it takes from pressing play to seeing video.
Live latency / delay — How far a live stream runs behind the real event.
DRM (digital rights management) — Copy protection that keeps licensed video secure. It’s why some content won’t play on unsupported or modified devices.
Picture quality terms
Resolution — The number of pixels in the picture.
| Name | Pixels | Also called |
|---|---|---|
| SD | 720×480 / 720×576 | Standard definition |
| HD | 1280×720 | 720p |
| Full HD | 1920×1080 | 1080p |
| 4K UHD | 3840×2160 | Ultra HD, 2160p |
| 8K | 7680×4320 | — |
Bitrate — The amount of data used per second of video. More bitrate generally means more detail and fewer artefacts. Our guide to video bitrate explains why it matters as much as resolution.
Codec — The method used to compress and decompress video. Common codecs are H.264 (AVC), H.265 (HEVC), VP9 and AV1, each more efficient than the last.
Frame rate (fps) — How many images are shown per second. Films are usually 24 fps; sport often 50 or 60 fps for smoother motion.
Compression artefacts — Visual flaws caused by squeezing video too hard: blockiness, banding in skies, or smearing in fast motion.
HDR (high dynamic range) — A format that allows brighter highlights, deeper shadows and richer colour than standard dynamic range (SDR).
HDR10 — The baseline HDR format, supported by every HDR TV. It uses one set of brightness instructions for a whole film.
HDR10+ — An HDR format that adjusts brightness scene by scene using dynamic metadata.
Dolby Vision — Dolby’s HDR format, also with scene-by-scene dynamic metadata. Our comparison of HDR10 vs Dolby Vision explains the real-world differences.
HLG (hybrid log-gamma) — An HDR format designed for live broadcasts.
Nits — A measure of screen brightness. HDR looks best on TVs that can reach high peak brightness.
Colour gamut — The range of colours a screen can show. Wider gamuts (like DCI-P3) look more vivid.
Upscaling — When a TV or device enlarges lower-resolution video to fit a higher-resolution screen.
Motion smoothing — TV processing that inserts extra frames. It can make films look unnaturally smooth — the “soap opera effect”.
Sound terms
Stereo — Two audio channels: left and right.
5.1 / 7.1 surround — Five or seven speakers around the room plus a subwoofer (the “.1”).
Dolby Digital / Dolby Digital Plus — Common compressed surround sound formats used by streaming services.
Dolby Atmos — An “object-based” format that places sounds in 3D space, including overhead. See our guide to Dolby Atmos streaming.
Lip sync — Whether sound matches mouth movements. Delays between audio and video cause lip-sync problems.
Soundbar — A single long speaker that sits under the TV, often with a separate subwoofer.
Connection and hardware terms
HDMI — The standard cable for connecting devices to TVs, carrying both picture and sound.
HDMI 2.1 — A newer HDMI version supporting higher bandwidth, 4K at 120 Hz and features like VRR.
ARC (audio return channel) — Lets a TV send sound back down an HDMI cable to a soundbar or receiver.
eARC (enhanced ARC) — An upgraded ARC with much more bandwidth, supporting lossless surround formats. Compared in HDMI ARC vs eARC.
HDCP — Copy protection built into HDMI. Mismatched HDCP versions can cause blank screens with 4K content.
CEC — An HDMI feature that lets one remote control several connected devices.
Streaming stick / box — A small device that plugs into a TV to run streaming apps.
Casting — Sending video from a phone or computer to a TV, using technologies such as Google Cast or AirPlay.
Service and business terms
SVOD (subscription video on demand) — Pay a monthly fee for unlimited access to a library.
AVOD (advertising video on demand) — Free or cheaper on-demand video supported by ads.
FAST (free ad-supported streaming TV) — Free, live-style channels with ads, like traditional TV but streamed.
TVOD (transactional video on demand) — Rent or buy individual titles.
vMVPD — An industry term for live TV streaming services that bundle traditional channels.
Simultaneous streams — How many devices can watch at the same time on one account.
Profile — A separate user space within an account, with its own watch history and recommendations.
Catch-up TV — On-demand access to recently broadcast programmes.
Cord-cutting — Cancelling cable or satellite TV in favour of streaming.
Keep learning
Bookmark this page — you’ll come back to it. And when you’re ready to put the jargon to work, these guides are a good next step:
- Internet speed for streaming — how many Mbps you really need.
- 4K streaming requirements — everything needed for a true 4K picture.
Frequently asked questions
What's the difference between resolution and bitrate?
Resolution is how many pixels make up the picture, such as 1920×1080 for Full HD. Bitrate is how much data is used per second to describe those pixels. A higher-resolution video with too little bitrate can look worse than a lower-resolution one with plenty.
Is UHD the same as 4K?
For TVs and streaming, yes. Consumer 4K, also called Ultra HD or UHD, means 3840×2160 pixels. Cinema 4K is slightly wider at 4096×2160, but you'll rarely see that distinction at home.
What does 'HDR' actually improve?
HDR widens the range between the darkest and brightest parts of the picture and allows richer colours. Highlights like sunlight or neon look more lifelike, and dark scenes keep more detail.
