File Formats

3GP is a multimedia container designed for 3G mobile phones with limited storage and bandwidth. It encodes video at low resolutions using H.263 or H.264 with AMR or AAC audio. While common on early smartphones, 3GP has been largely replaced by MP4 on modern devices.

7z is an open-source archive format that offers some of the highest compression ratios available. It supports multiple compression algorithms, AES-256 encryption, and solid archives. The 7-Zip program that creates it is free, open-source software.

AAC is a lossy audio codec that delivers better sound quality than MP3 at the same bitrate. It is the default audio format for Apple Music, YouTube, and most streaming services. AAC supports multichannel audio and is part of the MPEG-4 standard.

AC-3 is Dolby's multichannel audio codec used in DVDs, Blu-ray discs, cinema, and broadcast television. It encodes up to 5.1 channels of surround sound at bitrates from 32 to 640 kbps. AC-3 is the standard audio format for home theater systems.

AI is Adobe Illustrator's native vector graphics format for logos, illustrations, icons, and print-ready artwork. It preserves all Illustrator-specific features including layers, brushes, effects, and editable text. AI files are the standard deliverable in professional graphic design.

AIFF is Apple's uncompressed audio format, equivalent to WAV on macOS. It stores raw PCM audio with metadata chunks for markers, instrument definitions, and comments. AIFF is commonly used in professional audio production on macOS.

ALAC is Apple's lossless audio codec that compresses audio to about 60% of original size with no quality loss. It is supported natively on all Apple devices and is an alternative to FLAC for lossless music playback in the Apple ecosystem.

AMR is a speech-optimized audio codec used primarily in mobile phone voice recordings and 3G cellular networks. It dynamically adjusts its bitrate between 4.75 and 12.2 kbps to adapt to network conditions, prioritizing intelligible speech at very low bitrates.

APE is a lossless audio compression format that achieves higher compression ratios than FLAC but requires more CPU for encoding and decoding. It is popular in Asian audiophile communities and some music archiving circles.

APNG is an extension of PNG that adds animation support while maintaining backward compatibility. It supports full 24-bit color with 8-bit alpha transparency in every frame, producing smoother animations than GIF. Non-APNG-aware decoders display the first frame as a static PNG.

Apache Arrow IPC is a language-agnostic columnar format for in-memory data. It enables zero-copy data sharing between processes and languages (Python, R, C++, Java) without serialization overhead, making it the backbone of modern data processing pipelines.

ARW is Sony's proprietary raw image format used by Alpha mirrorless and DSLR cameras. It preserves the unprocessed sensor data with full dynamic range, allowing maximum flexibility in post-processing exposure, white balance, and color grading.

AVI is a legacy multimedia container developed by Microsoft that interleaves audio and video streams. While it supports many codecs, AVI lacks modern features like native streaming, variable frame rates, and subtitle tracks, making it largely obsolete for new content.

AVIF is a next-generation image format based on the open-source AV1 video codec. It delivers superior compression efficiency, often 50% smaller than JPEG and 20% smaller than WebP at equivalent quality. AVIF supports HDR, wide color gamut, transparency, and animation.

Avro is a row-based data serialization format that embeds its JSON schema within the file. It excels at schema evolution — readers and writers can have different but compatible schemas. Avro is the standard for Kafka message serialization and Hadoop data pipelines.

BMP is an uncompressed raster image format native to Microsoft Windows. It stores pixel data with no compression, resulting in very large files but zero quality loss. BMP is primarily used in Windows system graphics and as an intermediate format during image processing.

BSON is the binary serialization format used by MongoDB to store documents. It extends JSON with additional data types (dates, binary, ObjectId, decimal128) and is designed for efficient encoding, scanning, and in-place updates within a document database.

BZ2 files are compressed with bzip2, which achieves better compression ratios than gzip at the cost of slower speed. It is commonly used for source code distribution and Linux package archives where smaller downloads are preferred over compression speed.

C is the foundational systems programming language that powers operating systems, embedded systems, compilers, and performance-critical software. C provides direct memory access and minimal runtime overhead, making it the language closest to hardware while remaining portable.

C++ is a powerful systems programming language that extends C with object-oriented programming, templates, RAII, and the Standard Template Library (STL). It is used for game engines, browsers, databases, operating systems, and high-frequency trading systems.

CR2 is Canon's raw image format used by EOS DSLR cameras. It captures the full unprocessed sensor data with 14-bit color depth, giving photographers complete control over exposure, white balance, and noise reduction in post-processing.

CSS is the language that controls the visual presentation of web pages — layout, colors, fonts, spacing, animations, and responsive design. Every website uses CSS alongside HTML, and it is essential for creating modern, accessible, and visually appealing user interfaces.

CSV is the simplest format for tabular data — rows of values separated by commas (or other delimiters). It is universally supported by spreadsheets, databases, and programming languages, making it the lingua franca for data exchange and import/export workflows.

DLL is a Windows shared library format that contains code and data used by multiple programs simultaneously. DLLs enable modular software design, reduce memory usage through code sharing, and are fundamental to the Windows operating system and application ecosystem.

DNG is Adobe's open raw image format designed as a universal standard for camera raw data. It embeds the raw sensor data, metadata, and an XMP sidecar in a single self-contained file, solving the problem of proprietary raw format obsolescence.

DOC is the legacy binary file format used by Microsoft Word from 1997 through 2003. It stores formatted text, images, and objects in a proprietary compound binary structure. While largely superseded by DOCX, billions of .doc files still exist in archives and older systems.

DOCX is the default file format for Microsoft Word since Office 2007. It stores text, formatting, images, tables, and styles in a ZIP-compressed package of XML files. DOCX is the most common format for editable documents in business, education, and publishing.

EOT is a legacy web font format developed by Microsoft exclusively for Internet Explorer. It wraps OpenType fonts with compression and optional URL binding (restricting use to specific domains). EOT is effectively obsolete, needed only for IE8 and earlier.

EPS is a vector graphics format based on the PostScript page description language. It was the standard format for vector graphics exchange in print production before PDF and SVG adoption. EPS files can contain both vector and raster data with a low-resolution preview image.

EPUB is the open standard for reflowable e-books, used by Apple Books, Kobo, and most e-readers except Kindle. It adapts text to fit any screen size, supports embedded fonts, images, audio, video, and interactive content using HTML and CSS.

FLAC is an open-source lossless audio codec that compresses audio to 50-70% of the original size without losing a single bit of quality. It is the preferred format for audiophiles, music archiving, and any use case where preserving full audio fidelity matters.

FLV is the Flash Video container that powered online video in the 2000s through Adobe Flash Player. It was used by early YouTube, Hulu, and most video sharing sites before the HTML5 transition. FLV is effectively obsolete since Flash was discontinued in 2020.

GeoJSON is a JSON-based format for encoding geographic features — points, lines, polygons, and collections of geometries with associated properties. It is the standard for web mapping, geospatial APIs, and sharing geographic data between applications.

GIF is a bitmap image format best known for supporting simple animations. It uses lossless LZW compression but is limited to a 256-color palette per frame. GIF remains popular for short animated clips, reaction images, and simple graphics.

GLB is the binary, single-file variant of glTF 2.0, the 'JPEG of 3D.' It packages 3D geometry, materials, textures, and animations into one compact file. GLB is the standard for real-time 3D on the web, AR/VR, and game engines.

glTF is an open standard for 3D scenes and models, using JSON for the scene description with external binary (.bin) and texture files. It is designed for efficient real-time rendering and is the standard for WebGL, AR/VR, and 3D commerce. The binary variant (GLB) bundles everything into one file.

Go (Golang) files contain source code for Google's systems programming language. Go excels at building high-performance servers, CLI tools, and cloud infrastructure. It compiles to a single static binary with no runtime dependencies.

GPX is an XML-based format for storing GPS data — waypoints, tracks, and routes. It is the universal format for sharing running, cycling, hiking, and driving routes between GPS devices, fitness apps, and mapping software.

GZ is the file extension for gzip-compressed files, the standard compression tool on Unix and Linux systems. Gzip compresses a single file using the DEFLATE algorithm — to compress multiple files, it is typically paired with TAR to create .tar.gz (tgz) archives.

HDF5 is a file format and library for storing and managing large scientific datasets. It supports a hierarchical group/dataset structure similar to a filesystem, with datasets of arbitrary dimensions. HDF5 is the standard for satellite imagery, genomics, and physics simulations.

HEIC is a modern image format based on the HEVC (H.265) video codec, used as the default photo format on Apple devices. It offers roughly 50% better compression than JPEG while supporting features like depth maps and live photos. HEIC files maintain higher quality at smaller sizes but have limited support outside the Apple ecosystem.

HEIF is a modern image container that stores images (and image sequences) using HEVC or AV1 compression. It delivers the same visual quality as JPEG at roughly half the file size. HEIF supports depth maps, alpha channels, HDR, and image derivations in a single file.

HTML is the foundational markup language of the World Wide Web. It structures content with elements for headings, paragraphs, links, images, forms, and multimedia. Every web page is an HTML document interpreted by browsers to render visual content.

ICO is a container format used for icons on Microsoft Windows and website favicons. A single ICO file can contain multiple images at different sizes and color depths. It remains the standard format for browser tab icons (favicons) alongside PNG.

ICS is the standard calendar data format for exchanging events, appointments, to-dos, and free/busy information between calendar applications. It powers calendar invitations in email clients and is the foundation of CalDAV for calendar syncing.

ISO is a disc image format that contains an exact sector-by-sector copy of an optical disc (CD, DVD, or Blu-ray). It preserves the complete filesystem structure and is used for distributing operating system installers, software, and creating bootable media.

Java files contain source code for one of the most widely used enterprise programming languages. Java's 'write once, run anywhere' philosophy, strong typing, and the JVM ecosystem make it the backbone of Android development, enterprise systems, and big data.

JPEG (.jpeg) is the full-extension variant of .jpg, containing identical image data. Both extensions refer to the same JPEG compression standard — the difference is purely cosmetic. The .jpeg extension is less common but is technically the full name of the format.