An AVS file is best known as a plain-text AviSynth recipe that defines how to load and process video—resizing, trimming, cropping, deinterlacing, denoising, sharpening, frame-rate conversion, or subtitle insertion—and isn’t a standalone video; you open it either in a text editor to inspect commands or in a tool like VirtualDub2/AvsPmod to execute the script and preview results, usually feeding that into an encoder afterward, and you can recognize AviSynth scripts by readable commands such as Trim, plus small file size, while failures typically point to missing plugins, wrong file paths, or version mismatches, though some unrelated apps also use “AVS” for their own non-AviSynth configs that require the original program.
An AVS file is sometimes used as a project-definition file in AVS Video Editor, containing data such as your timeline structure, clip imports, edit points, transitions, titles, effects, and audio edits, which keeps the file small because it references media rather than embedding it, meaning it won’t play in typical media players and won’t read clearly in Notepad, and instead must be opened within AVS Video Editor, where missing media shows up if original files were moved or deleted, requiring relinking and copying of both the AVS file and its source clips when moving the project.
For more info regarding AVS file type look at the web-site. When I say an AVS file is usually a video script or project file, I mean it doesn’t hold actual audio/video like MP4 or MKV but instead stores instructions—a kind of blueprint—that another program uses to generate the final output; the most common example is an AviSynth script, a tiny text file telling AviSynth how to load a source video and apply steps like trimming, cropping, resizing, deinterlacing, denoising, sharpening, frame-rate changes, or subtitles, while in other cases an AVS is a video-editor project that keeps timeline edits and media references, which is why AVS files are small, don’t play in normal players, and must be opened either as text (scripts) or inside the software that created them (projects).
What appears inside an AVS varies by creator, but for AviSynth it’s a set of human-readable instructions forming a pipeline: the script begins by calling a source filter to load the video file, may load plugin DLLs, and then performs operations like trim cuts, edge cropping, resolution resizing, deinterlacing, noise reduction, sharpening, frame-rate adjustments, color/levels edits, or subtitle insertion, with every line serving a functional step, and common errors like “no function named …” or “couldn’t open file” typically point to missing filters or incorrect file paths.
