Glossary

The acronyms used on this site, in plain English.

AAC: Advanced Audio Coding The MPEG audio codec used by most streaming services.
ABR: Adaptive Bitrate Streaming The player switches between copies of a video encoded at different bitrates, the “ladder”, to match the viewer’s connection.
AC-3, E-AC-3: Dolby Digital, Dolby Digital Plus Dolby’s surround-sound codecs for broadcast and streaming. E-AC-3 also carries Dolby Atmos.
AC-4: Dolby AC-4 Dolby’s next-generation audio codec, used in ATSC 3.0, with dialogue enhancement and personalized audio.
AD: Audio Description A narration track that describes what happens on screen for blind and visually impaired viewers.
ADM, BWF: Audio Definition Model, Broadcast Wave Format The standard file format for delivering immersive, object-based audio masters.
AES: Audio Engineering Society The professional society for audio engineering: standards, papers and conventions.
AES67: AES67 The AES standard for professional audio over IP networks, used within SMPTE ST 2110.
AI, ML: Artificial Intelligence, Machine Learning Software that learns from data rather than following hand-written rules.
ATSC: Advanced Television Systems Committee Sets US digital TV broadcast standards, including ATSC 3.0 (NextGen TV).
AV1, AV2: AOMedia Video 1 and 2 Royalty-free video codecs from the Alliance for Open Media.
AVC: Advanced Video Coding (H.264) The most widely supported video codec.
BT.2087: ITU-R Recommendation BT.2087 The international reference for converting SDR colors (BT.709) into the wider HDR color space (BT.2020), so the two versions of a master can be compared like for like.
CAE: Content-Aware Encoding Encoding settings tuned to each title, or each shot, instead of one fixed ladder for everything.
CAMBI: Contrast Aware Multiscale Banding Index A metric that measures banding, the visible steps in smooth gradients like skies.
CDN: Content Delivery Network Servers spread around the world that cache video and deliver it close to viewers.
CIFRE: Conventions industrielles de formation par la recherche The French industrial PhD program: the doctorate is done inside a company, with a university lab.
CMAF: Common Media Application Format One set of video segments that both HLS and DASH players can use, instead of storing two copies.
CTA, CTA WAVE: Consumer Technology Association, Web Application Video Ecosystem The US consumer electronics association, and its project for streaming that plays the same on every device.
CTO: Chief Technology Officer The CTO Award is a company’s top technical recognition.
DAFx: Digital Audio Effects The international conference on digital audio effects.
DASH, DASH-IF: Dynamic Adaptive Streaming over HTTP, DASH Industry Forum The international ABR streaming standard (MPEG-DASH), and the forum that publishes its interoperability guidelines (IOP).
ΔE2000: Delta E 2000 (CIEDE2000) The standard measure of how different two colors look to the human eye. Below about 1, most people can’t see a difference.
DIS: Dialogue Intelligibility Score An objective measure of how easy dialogue is to understand, co-developed with Fraunhofer.
DRM: Digital Rights Management Encryption and licensing that protect content from copying.
DSP: Digital Signal Processing The mathematics behind audio and video processing.
DTVAG: DTV Audio Group The Sports Video Group’s forum for broadcast audio practice.
DVR: Digital Video Recorder Records TV for later. A cloud DVR keeps the recordings on the provider’s servers instead of a box at home.
EBU R 128: European Broadcasting Union, Recommendation 128 The European loudness recommendation for broadcast.
EP, JP, CN: European, Japanese and Chinese patents Patent applications filed with the European, Japanese and Chinese patent offices.
FCC: Federal Communications Commission The US communications regulator. It enforces the CALM Act on TV loudness.
FHD, UHD, 4K: Full HD, Ultra HD Picture resolutions: 1920×1080 for FHD, 3840×2160 for UHD, commonly called 4K.
GPU: Graphics Processing Unit The processor that runs machine-learning models fast.
HD: High Definition Picture resolution of 1280×720 or 1920×1080.
HDR, SDR: High Dynamic Range, Standard Dynamic Range HDR shows brighter highlights, deeper shadows and richer colour. SDR is the traditional range.
HDR10, PQ, PQ10: HDR10, Perceptual Quantizer, PQ10 HDR formats built on the PQ brightness curve. HDR10 adds static metadata; PQ10 carries none.
HE-AACv2: High-Efficiency AAC, version 2 The AAC variant for very low bitrates.
HEVC: High Efficiency Video Coding (H.265) The successor to AVC: about half the bitrate for the same quality, and the codec behind most 4K streaming.
HLG: Hybrid Log-Gamma An HDR format designed for live broadcast that still looks right on SDR TVs.
HLS: HTTP Live Streaming Apple’s ABR streaming protocol, the most widely used.
IAMF: Immersive Audio Model and Formats The Alliance for Open Media’s open format for immersive audio.
IEEE: Institute of Electrical and Electronics Engineers The largest professional society for engineers: standards, journals and conferences.
IP: Internet Protocol The networking protocol of the internet, now also used inside broadcast facilities.
ITU-R, ITU-T: International Telecommunication Union The UN agency for telecom standards. Its radio (R) and telecom (T) sectors publish standards such as BS.1770 for loudness and G.719 for audio coding.
JOC: Joint Object Coding How Dolby Atmos is carried inside E-AC-3 streams.
KPI: Key Performance Indicator A number that tracks how well a system or service performs.
LID: Language Identification Detecting which language is spoken in an audio track.
LLM: Large Language Model A machine-learning model trained on large amounts of text, such as the models behind ChatGPT or Claude.
MMS: Massively Multilingual Speech Meta’s open speech models, covering more than 1,000 languages.
MPEG, MPEG-H, MPEG-TS: Moving Picture Experts Group The ISO/IEC group behind most video and audio codecs. MPEG-H 3D Audio is its immersive audio codec; MPEG-TS (Transport Stream) is the container used in broadcast.
NAB: National Association of Broadcasters The US broadcasters’ association, and its yearly NAB Show in Las Vegas.
NGA: Next-Generation Audio Immersive and personalized audio systems such as Dolby AC-4 and MPEG-H.
OB: Outside Broadcast The production truck at a live venue, such as a stadium.
OTT, OVD: Over-The-Top, Online Video Distributor TV delivered over the internet instead of cable or satellite, and the services that deliver it.
PID: Packet Identifier The label of each stream, video, audio or data, inside an MPEG transport stream.
PSNR, SSIM: Peak Signal-to-Noise Ratio, Structural Similarity Classic objective video quality metrics.
QC: Quality Control Checking that video, audio and subtitles are correct before they reach viewers.
QoE: Quality of Experience What the viewer actually experiences: how fast playback starts, rebuffering and picture quality.
R&D: Research and Development
SCTE-35: Society of Cable Telecommunications Engineers, standard 35 Cue messages that mark ad breaks inside a stream.
SMPTE, ST 2110: Society of Motion Picture and Television Engineers The film and TV engineering society. ST 2110 is its standard for professional video and audio over IP.
SSAI, SGAI: Server-Side Ad Insertion, Server-Guided Ad Insertion Ads stitched into the stream by the server, or played by the player on the server’s instructions.
SVG: Sports Video Group The association of sports broadcast production professionals.
SVTA: Streaming Video Technology Alliance An industry alliance that publishes best practices for streaming.
USAC: Unified Speech and Audio Coding The MPEG-D codec, known as xHE-AAC, that handles speech and music at low bitrates.
USPTO: United States Patent and Trademark Office
VAD: Voice Activity Detection Finding where speech occurs in an audio track.
VAST: Video Ad Serving Template The industry standard that tells a video player which ad to play.
VMAF: Video Multimethod Assessment Fusion Netflix’s perceptual video quality metric, trained on viewers’ scores.
VOD: Video On Demand Shows and films watched whenever the viewer chooses, as opposed to live.
VP9: VP9 Google’s royalty-free video codec, widely used on YouTube and in browsers.
VQ: Video Quality How good the picture looks, measured by metrics and by viewers.
VR, VRIF: Virtual Reality, Virtual Reality Industry Forum Here, 360° video, and the forum that published guidelines for delivering it.
WASPAA: Workshop on Applications of Signal Processing to Audio and Acoustics The IEEE audio signal processing workshop.