GOAT LabWhat the WebM extension tells you
Understand .webm, the video/webm MIME type and the difference between a container and a codec. Check examples and compare WebM with MP4.
Reference details and sources
WebM is a media container based on a subset of Matroska. A container organizes tracks and metadata; the codecs used to encode the audio and video are a separate part of playback compatibility.
The entry includes an FFmpeg example and related formats. Check the actual codecs and your target player before distribution; changing .webm to .mp4 by renaming does not transcode the media.
Related references and tools
Primary sources
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What is FORMATS?
FORMATS is a browsable dictionary of 134 file formats, from CSV and JSON to PDF, SVG, Parquet, FITS, DICOM, and SQLite. Every format records its extensions, MIME types, whether it is text or binary, its year, and its creator or standard, plus pros, cons, a code example, tools, and related formats.
How does it work?
All data is served from static JSON, so no server or sign-in is needed. Browse the full table or filter by audience (General, Researcher, Developer) or by 11 categories. Open any format for its "Three Readers" view, pros and cons, an example, and tools and libraries.
When should I use it?
Use FORMATS when you need to quickly understand or compare a file format: its extension, MIME type, whether it is text or binary, when it appeared, and how it is used. It is built for the moment you hit an unfamiliar extension or must choose between similar formats like CSV vs TSV or PNG vs WebP.
At a glance
| Formats documented | 134 file formats |
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| Categories | 11 (Tabular, Document, Image, Citation, Config, Archive, Audio/Video, Science, Geo/3D, Crypto, Database) |
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| Reader perspectives per format | 3 — General, Researcher, Developer |
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| Text vs binary | 50 text, 84 binary |
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| Year range | 1963 (TXT) to 2021 (JPEG XL) |
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| Largest category | Tabular & Structured Data — 19 formats |
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| Per-entry data | Extensions, MIME types, type, year, creator, pros/cons, example, tools, related |
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| Example entry: CSV | text/csv, text, 1972, RFC 4180 (2005) |
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Frequently asked questions
How many file formats does FORMATS cover?
FORMATS documents 134 file formats organized into 11 categories: Tabular & Structured Data, Document, Image & Graphics, Bibliography & Citation, Config & Development, Archive & Compression, Audio & Video, Scientific Data, Geospatial & 3D, Cryptography & Certificates, and Database & Key-Value Store.
What does each format entry include?
Each entry lists extensions, MIME types, text or binary type, release year, and creator or standard, plus a description, pros and cons, a code example, tools and libraries, related formats, and a trivia note. All 134 entries also include separate General, Researcher, and Developer explanations.
What is the oldest and newest format listed?
The oldest is TXT (1963) and MARC21 (1968); the newest is JPEG XL (2021) and DuckDB (2019). Across all entries, release years span 1963 to 2021.
Are the formats text or binary?
Of the 134 formats, 50 are text-based (such as CSV, JSON, YAML, Markdown, and SVG) and 84 are binary (such as PDF, PNG, MP4, Parquet, and SQLite). Each entry is tagged Text or Binary.
Does FORMATS need an account or internet connection?
No. FORMATS is a fully static reference built with Vite and vanilla JavaScript that loads its data from static JSON. There is no account, no upload, and no server-side processing.
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