The Convert Glossary

A standardized lossy audio compression format designed to be the successor to MP3. AAC generally delivers better sound quality than MP3 at the same bitrate. It is the default audio format for YouTube, Apple Music, and many streaming platforms.

A modern image format based on the AV1 video codec. AVIF provides significantly better compression than JPEG and PNG while supporting HDR, wide color gamut, and animation. It is increasingly supported by modern browsers.

An uncompressed audio format developed by Apple, similar to WAV. AIFF files store PCM audio data and are commonly used in professional audio editing on macOS. Like WAV, AIFF files are large but preserve exact original audio quality.

A lossless audio compression format developed by Apple. ALAC files are approximately 40-60% smaller than uncompressed audio while preserving bit-perfect quality. It is supported natively by iOS, macOS, and iTunes.

An additional data channel in an image that stores transparency information for each pixel. Formats like PNG, WebP, AVIF, and TIFF support alpha channels, allowing soft, semi-transparent edges. JPEG does not support alpha channels.

An extension of the PNG format that supports animation. APNG uses the same lossless compression as PNG and supports full 24-bit color with 8-bit transparency. It is supported by all modern browsers and is an alternative to GIF for animations.

The proportional relationship between the width and height of an image or video, expressed as width:height (e.g., 16:9, 4:3). Common aspect ratios include 16:9 for widescreen video, 4:3 for traditional TV, and 1:1 for square images.

An open, royalty-free video codec developed by the Alliance for Open Media. AV1 delivers approximately 30% better compression than VP9 and H.265/HEVC. It is designed for web video streaming and is increasingly supported by modern browsers.

A multimedia container format introduced by Microsoft in 1992. AVI files can contain both audio and video data in a single file. While widely supported on Windows, AVI is an older format with limitations compared to MP4 and MKV, such as lack of subtitle and modern codec support.

The number of bits processed per unit of time in a media file, typically measured in kilobits per second (kbps) or megabits per second (Mbps). Higher bitrates generally produce better quality but larger file sizes.

A raster image format developed by Microsoft that stores pixel data without compression. BMP files are lossless but typically very large. They are rarely used on the web due to their size.

The process of converting multiple files simultaneously rather than one at a time. Batch conversion saves significant time when processing large numbers of files and is supported by most file conversion tools, including Convertly.

The number of bits used to represent the color of each pixel in an image. Common bit depths include 8-bit (256 colors), 16-bit (65,536 colors), 24-bit (16.7 million colors, "TrueColor"), and 32-bit (24-bit color + 8-bit alpha). Higher bit depth means more colors and smoother gradients.

A general-purpose lossless compression algorithm developed by Google. Brotli typically achieves 20-26% better compression ratios than Gzip for web content. It is widely used for HTTP compression and is supported by all modern browsers.

A program or algorithm that encodes and decodes digital data, typically audio or video. Common codecs include H.264, H.265 (HEVC), AAC, and Opus. The codec determines how media data is compressed and decompressed.

A specific organization of colors that defines how colors are represented in a digital image. Common color spaces include sRGB (standard for web), Adobe RGB (wider gamut for print), and Display P3 (Apple devices).

A file format that can contain multiple types of data — typically video, audio, and subtitles — in a single file. Examples include MP4, MKV, AVI, and MOV. The container holds the data; the codec determines how it is encoded.

A plain text format for storing tabular data where each line is a row and columns are separated by commas. CSV is universally supported by spreadsheet applications, databases, and programming languages.

An encoding method where the bitrate remains fixed throughout the entire file. CBR produces predictable file sizes and is suitable for streaming where consistent bandwidth is needed. However, it may waste bits on simple scenes and lack quality in complex ones.

A compression technique that reduces color information more than brightness information, since the human eye is less sensitive to color detail. Common schemes include 4:4:4 (no subsampling), 4:2:2 (half horizontal chroma), and 4:2:0 (half horizontal and vertical chroma). Used in JPEG and most video codecs.

A subtractive color model used in color printing. CMYK uses four ink channels — cyan, magenta, yellow, and key (black) — to produce printed colors. Images intended for print are typically converted from RGB to CMYK before printing.

The range of distinct colors an image or display can represent, determined by the bit depth per channel. 8-bit per channel (24-bit total) is standard for most images and displays. Higher color depths (10-bit, 12-bit, 16-bit) are used in HDR and professional workflows.

The range of colors that a display, image, or color space can reproduce. Wider gamuts like Adobe RGB and Display P3 can show more saturated colors than the standard sRGB gamut. Converting between gamuts may cause color shifts if colors fall outside the target gamut.

A standardized definition of how colors are interpreted in a digital file, ensuring consistent color reproduction across devices. ICC profiles are the most common standard. Profiles are embedded in image files and used by browsers, printers, and editing software to render colors accurately.

The ratio of luminance between the brightest white and the darkest black in an image or display. Higher contrast ratios produce more dynamic, visually striking images. HDR content typically targets contrast ratios of 1000:1 or higher.

A measure of print resolution indicating how many individual dots of ink a printer can place in one inch. Higher DPI means sharper printed images. DPI is often confused with PPI (pixels per inch), which refers to screen resolution.

A mathematical transform widely used in lossy image and video compression, including JPEG, MPEG, and H.264. DCT converts spatial pixel data into frequency components, allowing compression algorithms to discard high-frequency details that are less visible to the human eye.

The process of converting interlaced video (alternating fields) into progressive video (full frames). Deinterlacing is necessary when converting older TV footage (NTSC/PAL) for modern progressive displays. Various algorithms exist, from simple line doubling to advanced motion-compensated methods.

A compressed document format designed for scanned documents and images. DjVu uses technologies like separable compression of text and backgrounds to achieve file sizes significantly smaller than PDF for scanned content. It is popular in digital libraries and archives.

The default word processing document format used by Microsoft Word since 2007. DOCX is based on Office Open XML and uses ZIP-based compression. It supports text, images, tables, charts, and formatting. DOCX can be converted to PDF, HTML, and other formats.

An audio encoding format used in Super Audio CD (SACD). DSD uses 1-bit delta-sigma modulation at very high sampling rates (typically 2.8224 MHz). DSD is favored by audiophiles for its analog-like sound characteristics but requires specialized playback equipment.

An open e-book file format that uses XHTML and CSS for content rendering. EPUB is the industry standard for e-books and is supported by most e-readers except Amazon Kindle (which uses AZW/MOBI).

A standard that specifies formats for images, sound, and ancillary tags used by digital cameras. EXIF data includes metadata like camera model, exposure settings, timestamp, and GPS coordinates. This data can be preserved or stripped during conversion.

A vector image format based on PostScript, commonly used for logos, illustrations, and print-ready artwork. EPS files can contain both vector and raster elements. While widely used in professional printing, EPS is being replaced by PDF and SVG in modern workflows.

An audio format that compresses audio without any loss of quality. FLAC files are typically 50-60% smaller than uncompressed WAV files while preserving the exact original audio data.

A free, open-source multimedia framework that can decode, encode, transcode, stream, and filter virtually any audio and video format. FFmpeg is the backbone of many file conversion tools, including Convertly, which runs it in-browser via WebAssembly.

A video container format used by Adobe Flash Player. FLV was the dominant web video format before HTML5. Since the deprecation of Flash, FLV has been largely replaced by MP4 and WebM. Converting FLV to MP4 is common for preserving legacy video content.

The number of individual frames (images) displayed per second in a video, measured in FPS. Common frame rates include 24 FPS (cinema), 25 FPS (PAL TV), 30 FPS (NTSC TV), 60 FPS (gaming/smooth motion), and 120 FPS (high-speed). Higher frame rates produce smoother motion but larger file sizes.

A bitmap image format that supports up to 256 colors per frame and animation. GIF uses lossless LZW compression. Despite its age and color limitations, GIF remains popular for short animations and memes.

The cumulative quality degradation that occurs when a lossy file is repeatedly re-encoded. Each encode pass discards more data, leading to progressively worse quality. To avoid generation loss, keep a lossless master copy and only encode to lossy formats once for distribution.

An open standard for 3D models and scenes, developed by the Khronos Group. glTF is designed for efficient transmission and loading of 3D content on the web. The binary version, GLB, packages all assets (geometry, textures, animations) into a single file.

A widely used lossless compression format and algorithm based on DEFLATE. Gzip is commonly used for compressing single files on Unix/Linux systems and for HTTP compression on the web. Gzip files typically have the .gz extension.

A modern image format based on the HEVC video codec. HEIC files are approximately half the size of JPEGs at the same quality. Apple has used HEIC as the default photo format on iOS since 2017.

The standard markup language for creating web pages. HTML files contain structured content with tags that define elements like headings, paragraphs, links, and images. HTML can be converted to PDF for printing or archiving.

A widely used video codec also known as Advanced Video Coding (AVC). H.264 is the most common codec for web video, Blu-ray discs, and streaming. It offers excellent compression efficiency and is supported by virtually all devices and browsers. Most MP4 files use H.264 video.

A video codec also known as High Efficiency Video Coding (HEVC). H.265 provides approximately 50% better compression than H.264 at the same quality. It supports resolutions up to 8K. However, licensing costs have limited its adoption compared to H.264 and AV1.

A technology that expands the range of brightness and color in images and video beyond standard dynamic range (SDR). HDR content captures and displays more detail in both shadows and highlights. Common HDR formats include HDR10, HDR10+, Dolby Vision, and HLG.

A lossless data compression algorithm that assigns shorter codes to more frequent symbols and longer codes to rarer ones. Huffman coding is used as a component in many compression formats, including JPEG, MP3, DEFLATE (ZIP/Gzip), and Brotli.

A image file format used for icons in Microsoft Windows. ICO files can contain multiple sizes and color depths of the same icon. They are commonly used for website favicons.

A standardized color profile defined by the International Color Consortium (ICC). ICC profiles describe how a device (monitor, printer, camera) reproduces colors, enabling accurate color matching across devices. ICC profiles can be embedded in image files like TIFF, JPEG, and PNG.

A metadata container embedded in MP3 files that stores information like track title, artist, album, year, genre, and album art. ID3 tags come in two main versions: ID3v1 (fixed 128-byte tag at file end) and ID3v2 (variable-length tag at file beginning with richer metadata).

A video display technique where each frame is divided into two fields — one with odd-numbered lines and one with even-numbered lines. Interlacing was used in analog TV (NTSC, PAL) to reduce bandwidth. Modern displays use progressive scan, making deinterlacing necessary for older content.

A lightweight data-interchange format that is easy for humans to read and write and easy for machines to parse and generate. JSON uses key-value pairs and arrays, making it the most popular data format for web APIs.

The most common image format for photographs and web images. JPEG uses lossy compression, which reduces file size by discarding some image data. It supports 16.7 million colors but does not support transparency.

A complete, self-contained video frame that contains all the data needed to display the image, without reference to other frames. Keyframes (I-frames) serve as reference points for inter-frame compression. More keyframes improve seeking accuracy but increase file size.

A compression method that reduces file size without losing any data. When decompressed, the file is identical to the original. Examples include PNG for images, FLAC for audio, and ZIP for archives.

A compression method that reduces file size by permanently discarding some data. The decompressed file is not identical to the original but is typically close enough to be acceptable. Examples include JPEG, MP3, and MP4.

A lossless data compression algorithm used in the 7z format. LZMA achieves higher compression ratios than DEFLATE (used in ZIP) at the cost of slower compression speed. LZMA2 is an improved version used in modern 7z implementations.

A lossless data compression algorithm used in GIF, TIFF, and other formats. LZW builds a dictionary of repeated patterns during compression, replacing them with shorter codes. LZW was patented by Unisys, which led to the development of PNG as a patent-free alternative to GIF.

An open-source container format that can hold unlimited video, audio, subtitle tracks, and metadata in a single file. MKV is popular for high-quality video archiving because it supports virtually any codec.

A QuickTime container format developed by Apple. MOV files typically use MPEG-4 or H.264 video codecs. The format is commonly used in professional video editing and on Apple devices.

The most widely used audio format for music distribution. MP3 uses lossy compression to reduce file size by discarding sounds that are less audible to human ears. It supports bitrates from 32 to 320 kbps.

A digital multimedia container format most commonly used to store video and audio. MP4 is the most widely supported video format across devices, browsers, and platforms. It typically contains H.264 or H.265 video with AAC audio.

Data that describes other data. In file conversion, metadata includes information like creation date, author, camera settings, GPS location, and codec details. Metadata can be preserved, modified, or stripped during conversion.

A common conversion that re-packages video from Apple's QuickTime container to the more universally compatible MP4 container. This is often a lossless process since both formats can use the same H.264 codec.

An audio file container based on the MP4 format, typically containing AAC or ALAC audio. M4A files are commonly associated with Apple's iTunes and Apple Music. M4A with AAC generally provides better quality than MP3 at the same bitrate.

A block of pixels (commonly 16×16) used as the basic unit for compression in video codecs like H.264 and MPEG-2. Each macroblock is encoded using spatial and temporal prediction. Modern codecs like H.265 use variable-size Coding Tree Units (CTUs) ranging from 8×8 to 64×64.

An e-book format originally developed by Mobipocket and later acquired by Amazon. MOBI was the primary format for Amazon Kindle before being replaced by AZW3/KF8. MOBI supports text, images, and basic formatting. EPUB to MOBI conversion is common for Kindle compatibility.

A family of standards for audio and video compression developed by the ISO/IEC working group. MPEG standards include MPEG-1 (used in VCD and MP3), MPEG-2 (used in DVD and digital TV), MPEG-4 (used in MP4, H.264, and AAC), and MPEG-H (used in HEVC).

The analog television standard used in North America, Japan, and parts of South America. NTSC defines a frame rate of 29.97 FPS (approximately 30) with 480 visible lines of resolution, using interlaced scanning. NTSC has been replaced by digital broadcasting (ATSC).

An open-source audio format that uses the Vorbis lossy compression codec. OGG provides quality comparable to MP3 at smaller file sizes. It is commonly used in open-source software and gaming.

A technology that converts text in images or scanned documents into editable, searchable digital text. OCR is commonly used when converting scanned PDFs to text, extracting text from images, or digitizing printed documents. Modern OCR engines can recognize multiple languages and formatting.

A versatile, open-source audio codec developed by the Xiph.Org Foundation. Opus handles both speech and music with excellent quality at bitrates from 6 kbps to 510 kbps. It is used in WebRTC, Discord, and YouTube, and is supported by all modern browsers.

A file format developed by Adobe that preserves document formatting across different devices and operating systems. PDF files can contain text, images, interactive elements, and forms. They are the standard for sharing documents that need to look the same everywhere.

A raster image format that uses lossless compression and supports transparency (alpha channel). PNG is ideal for graphics with sharp edges, text, or transparent areas. It does not support animation (except for APNG).

A measure of pixel density on a screen or in a digital image. Higher PPI means sharper display. PPI is often confused with DPI, but PPI refers to digital displays while DPI refers to print output.

The analog television standard used in Europe, Australia, and parts of Asia and Africa. PAL defines a frame rate of 25 FPS with 576 visible lines of resolution, using interlaced scanning. PAL has been replaced by digital broadcasting (DVB).

The standard method for digitally representing analog audio signals. PCM samples the audio waveform at regular intervals and quantizes each sample to a numerical value. Uncompressed WAV and AIFF files store PCM audio. PCM is the foundation of all digital audio formats.

The default presentation format used by Microsoft PowerPoint since 2007. PPTX is based on Office Open XML and uses ZIP-based compression. It supports slides, text, images, animations, transitions, and embedded media. PPTX can be converted to PDF for sharing.

A video display method where each frame is drawn completely in sequence, line by line, as opposed to interlacing which alternates fields. Progressive scan produces smoother, flicker-free images and is the standard for all modern displays. Video resolutions often indicate scan type (e.g., 1080p, 720p).

The native image format for Adobe Photoshop. PSD files support multiple layers, adjustment layers, masks, text, vector shapes, and other Photoshop features. PSD files are typically large and are usually exported to JPEG, PNG, or TIFF for final use.

An image composed of a grid of individual pixels, each with a specific color value. Raster images (like JPEG, PNG, BMP) lose quality when scaled up. Contrast with vector images, which scale infinitely without quality loss.

The dimensions of an image or video, typically expressed as width × height in pixels (e.g., 1920×1080). Higher resolution means more detail but larger file size. Common video resolutions include 720p, 1080p, 4K, and 8K.

A proprietary archive file format that supports data compression, error recovery, and file spanning. RAR generally achieves higher compression ratios than ZIP but requires proprietary software to create (though extraction is open).

A minimally processed image file from a digital camera sensor, containing all the raw data captured by the sensor. RAW files offer maximum editing flexibility (white balance, exposure, color) but require specialized software. Each camera manufacturer has its own RAW format (e.g., CR2 for Canon, NEF for Nikon, ARW for Sony).

An additive color model where red, green, and blue light are combined in varying intensities to produce other colors. RGB is the standard color model for digital displays, cameras, and web images. Most image formats store color data in RGB. Converting RGB to CMYK is necessary for printing.

A simple lossless compression method that replaces sequences of identical values with a single value and a count. RLE is effective for images with large areas of uniform color (like simple graphics or icons) but inefficient for photographic content. RLE is used in BMP, PCX, and some TIFF files.

A document format developed by Microsoft for cross-platform text exchange. RTF supports basic text formatting (bold, italic, fonts, colors, tables) and can be opened by most word processors. RTF is simpler than DOCX but less capable. It is commonly used for document interchange between different applications.

An XML-based vector image format that defines graphics using paths, shapes, and text. SVG images scale to any size without quality loss, making them ideal for logos, icons, and illustrations on the web.

The number of audio samples captured per second during digital recording, measured in Hertz (Hz). Common sample rates include 44.1 kHz (CD quality), 48 kHz (professional audio and video), 96 kHz (high-resolution), and 192 kHz (studio mastering). Higher sample rates capture higher frequencies but produce larger files.

A plain-text subtitle file format widely used for video subtitles. SRT files contain sequentially numbered subtitle entries with start and end timestamps and text. SRT is supported by virtually all video players and platforms. It can be converted to VTT for web video.

A flexible raster image format commonly used in professional photography and printing. TIFF supports both lossy and lossless compression, multiple layers, and high color depths. Files are typically large.

A file format that combines multiple files into a single archive file without compression. Tar files typically have the .tar extension and are often compressed with Gzip (.tar.gz) or Bzip2 (.tar.bz2). Tar is the standard archive format on Unix and Linux systems.

The process of converting media from one codec or encoding to another, typically involving re-encoding the data. For example, converting H.264 video to H.265 for smaller file size, or converting WAV audio to MP3. Transcoding may involve quality loss when converting between lossy formats.

A color depth standard that uses 24 bits per pixel — 8 bits each for red, green, and blue — to represent 16,777,216 distinct colors. TrueColor is the standard for most digital images, displays, and web content. It is sufficient for photorealistic images and is supported by JPEG, PNG, and most image formats.

An image defined using mathematical paths rather than pixels. Vector images (like SVG) can be scaled to any size without losing quality. They are ideal for logos, icons, and illustrations but not suitable for photographs.

An encoding method where the bitrate changes dynamically based on the complexity of the content. VBR allocates more bits to complex scenes and fewer to simple ones, producing better overall quality at a given file size compared to CBR. VBR is preferred for file storage, while CBR is often used for streaming.

An open-source, royalty-free lossy audio codec developed by the Xiph.Org Foundation. Vorbis is the audio codec used in OGG files. It provides quality comparable to or better than MP3 at equivalent bitrates. Vorbis is commonly used in open-source software, gaming, and Spotify streaming.

An open, royalty-free video codec developed by Google. VP9 is the successor to VP8 and provides compression efficiency comparable to H.265/HEVC. It is primarily used for web video on YouTube and is supported by Chrome, Firefox, and Edge. VP9 is being succeeded by AV1.

A W3C standard subtitle and caption format for web video, also known as WebVTT. VTT files are plain text with timing cues, similar to SRT but with additional features like styling, positioning, and metadata. VTT is the native subtitle format for HTML5 video.

An uncompressed audio format developed by Microsoft and IBM. WAV files preserve the exact original audio data, making them ideal for audio editing and archiving. However, they are very large compared to compressed formats.

An open-source video container format developed by Google specifically for web use. WebM typically uses VP8 or VP9 video codecs with Vorbis or Opus audio. It is supported by most modern browsers.

A modern image format developed by Google that provides both lossy and lossless compression. WebP files are 25-35% smaller than comparable JPEGs and PNGs. The format also supports transparency and animation.

A binary instruction format that allows high-performance applications to run in web browsers. Convertly uses WASM to run tools like FFmpeg directly in your browser, enabling server-quality file conversion without uploading files.

An audio format developed by Microsoft as part of the Windows Media framework. WMA supports both lossy and lossless compression. WMA Lossless provides bit-perfect audio reproduction. The format is primarily used on Windows and has declined in popularity compared to MP3 and AAC.

A video compression format developed by Microsoft. WMV files use the ASF container and typically contain WMV video with WMA audio. The format was designed for streaming on Windows but has been largely replaced by MP4 and WebM. Converting WMV to MP4 is common for cross-platform compatibility.

A markup language that defines rules for encoding documents in a format that is both human-readable and machine-readable. XML is widely used for configuration files, data exchange, and document markup.

The default spreadsheet format used by Microsoft Excel since 2007. XLSX is based on Office Open XML and uses ZIP-based compression. It supports formulas, charts, pivot tables, and multiple worksheets. XLSX can be converted to CSV for data interchange or to PDF for sharing.

A human-friendly data serialization standard for all programming languages. YAML uses indentation for structure, making it more readable than JSON or XML. It is commonly used for configuration files.

A color space that separates brightness (luma, Y') from color information (chroma, Cb and Cr). YCbCr is used in JPEG compression, video encoding, and television broadcasting. This separation enables chroma subsampling, which reduces file size by discarding color detail that is less perceptible to the human eye.

An archive file format that supports lossless data compression. A ZIP file may contain one or more files or directories that have been compressed. ZIP is the most common archive format and is supported by virtually all operating systems.

A fast lossless compression algorithm developed by Facebook. Zstandard offers compression ratios similar to LZMA with much faster decompression speeds. It supports compression levels from 1 (fastest) to 22 (highest ratio) and is increasingly used as a modern replacement for Gzip and DEFLATE.