File knowledge base
File format glossary
Plain-English definitions for the image, PDF, video, audio and file terms used throughout NEXDOWNLOAD.
Quick reference
Compare image formats Understand the setting before changing it
These definitions explain the practical meaning of common terms. Open the linked guides when you need a deeper comparison or workflow.
- Aspect ratio
- The proportional relationship between width and height, such as 16:9, 1:1 or 4:5.
- Bitrate
- The amount of data used per second of audio or video. Higher bitrate can allow more detail but usually creates a larger file.
- Codec
- The method used to encode and decode audio or video inside a container such as MP4 or WebM.
- Compression
- A process that reduces file size. Lossless compression preserves the original information; lossy compression discards some information to save more space.
- Container
- A file structure that holds video, audio, timing and metadata. MP4 and WebM are containers, not single codecs.
- DPI / PPI
- Values describing print or pixel density. For ordinary web display, pixel dimensions usually matter more than a DPI label stored in the file.
- EXIF
- Metadata commonly stored in photographs, including camera details, capture settings, time and sometimes location.
- Frame rate
- The number of video or animation frames shown each second, commonly written as fps.
- HEIC / HEIF
- An efficient image container often used by phones. Some websites and older apps require conversion to JPG or PNG.
- JPEG / JPG
- The same widely supported lossy image format, commonly used for photographs.
- Lossless
- A process that preserves all original image or audio information represented by the format. Lossless does not always mean the file will be small.
- Lossy
- A process that removes some information to reduce size. Repeated lossy conversions can accumulate visible or audible artifacts.
- Metadata
- Information about a file in addition to its visible or audible content, such as dates, dimensions, camera details or descriptive fields.
- PNG
- A lossless raster image format that supports transparency and is well suited to graphics, screenshots and line art.
- Raster image
- An image made from a fixed grid of pixels. JPG, PNG and WebP are raster formats.
- Resolution
- For digital images and video, usually the pixel dimensions, such as 1920 × 1080.
- SHA-256
- A cryptographic hash algorithm that creates a fixed-length checksum for comparing file contents.
- Transparency / alpha
- Pixel information that allows parts of an image to be fully or partly transparent. JPG does not support it.
- Vector image
- Artwork described by paths and shapes rather than a fixed pixel grid. SVG is a common web vector format.
- WebP
- A modern raster image format that supports lossy compression, lossless compression and transparency.
- WebM
- An open media container commonly supported by modern browsers for web video and audio.
Need a practical answer?
Use the glossary with a tool or guide
Definitions explain the terminology; tool pages explain the controls, trade-offs and checks for the result you are creating.