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Donations Hello everyone! I have been hosting this wiki for a long time. I have been hosting it since around 2010 (from Richard Berg). Although the content is maintained by several people, and I'm very grateful for their time, the hosting costs a lot of money. If you are happy with the site, please make a donation! I would be very grateful and we can keep this site alive: You can donate by buying me a coffee: https://buymeacoffee.com/avisynth You can donate using PayPal: https://paypal.me/avisynth/ What is AviSynth? AviSynth is a powerful tool for video post-production. It provides ways of editing and processing videos. AviSynth works as a frameserver, providing instant editing without the need for temporary files. AviSynth itself does not provide a graphical user interface (GUI), but instead relies on a script system that allows advanced non-linear editing. While this may at first seem laborious and unintuitive, it is remarkably powerful and is a very good way to manage projects in a precise, consistent, and reproducible manner. Because text-based scripts are human readable, projects are inherently self-documenting. The scripting language is simple yet powerful, and complex filters can be created from basic operations to develop a sophisticated palette of useful and unique effects. AviSynth is free open-source software, and licensed under the GNU General Public License GPLv2.
New to AviSynth – Start Here Your first script – A guide for total newbies. Getting started – An introductory guide. Grammar – An introduction to the AviSynth scripting language. Filter introduction – An introductory guide to most common AviSynth filters. Script examples – Putting everything together in the real world. AviSynth FAQ – Answers to many common problems. More information (How does it work? When is it useful? Why no GUI? What applications work well with AviSynth?) Guides – Guides explaining the basics, tips on specific conversion types and common tasks. Troubleshooting your scripts and configuration.	Download AviSynth Current Builds AviSynth+ New features, backward compatible, native support for Unix-like OSes. Wiki page Homepage (avs-plus.net)  Latest release (GitHub)  Discussion at forum.doom9.org Deprecated Official builds v.2.6.0 ST, 32-bit at SourceForge Deprecated Unofficial builds v.2.6.0 MT, 32-bit, author SET at forum.doom9.org Universal Installer Install—and quickly switch between—AviSynth versions: Avisynth 2.5.8, 2.6.0, 2.6.0 MT, 2.6.1 Alpha Avisynth+ 32-bit, 64-bit Get it here at forum.doom9.org Deprecated Multithread Version v.2.5.8 MT, 32-bit, author SET, discussion at forum.doom9.org v.2.5.8 MT, 64-bit, author SET, compiled by JoshyD at forum.doom9.org AvxSynth AviSynth 2.5.8 running on Ubuntu 32/64. Old Bugs and issues Known Issues in v2.58. Known Issues in v2.60.
Script Syntax The official reference documentation. AviSynth Syntax overview Script variables – How to declare and use them in scripts. Operators – Available operators and relative precedence. Internal functions – General purpose functions for math, logic etc. Clip properties – Properties such as Width, Height, Framerate etc. Control structures – Language constructs for script flow control. User defined script functions – How to define and use them in scripts. Plugins – How to load them (AviSynth, VirtualDub, VFAPI and C-plugins); autoloading and name-precedence explained. Most External filters are plugins; the rest are regular scripts. Runtime environment – Scripting on a per-clip frame basis. Function objects – AVS+user defined functions as variables, capture external variables, use them in ScriptClip instead of stringified script fragments.	Filters and Utilities Internal filters – Included media filters, organized by category. External filters – Hundreds of separately downloadable filters, organized by category. User pages hosted on this site: AviSynth Filter Collection – Warpenterprises 20250316: the names of the AviSynth 2.5 plugins are messed up, put 5F before 25 in the filename (thus for example avsmon25a_5F25_dll_20030125.zip instead of avsmon25a_25_dll_20030125.zip) Fizick’s AviSynth plugins vcmohan’s Plugin Filters stickboy’s AviSynth Stuff Shared functions – Commonly used script functions. Utilities – A list of GUIs, command-line, batch and other AviSynth related utilities.
Scripting reference Beyond scripting basics Scripting reference overview The full AviSynth grammar – The AviSynth grammar revisited and explained in detail. The script execution model – The steps behind the scenes from the script to the final video clip output. The filter graph. Scope and lifetime of variables. Evaluation of runtime scripts. User functions – How to effectively write and invoke user defined script functions; common pitfalls to avoid; ways to organise your function collection and create libraries of functions, and many more. Block statements – Techniques and coding idioms for creating blocks of AviSynth script statements. Arrays – Using arrays (and array operators) for manipulating collections of data in a single step. Scripting at runtime – How to unravel the power of runtime filters and create complex runtime scripts that can perform interesting (and memory/speed efficient) editing/processing operations and effects.
Advanced topics Advanced Scripting Tips – Using recursion, weaving 3 clips, and other programming tips. Advanced topics – Chroma Upsampling Error, color conversions, hybrid video, motion compensation, and other advanced subjects. Aspect ratios explained – Introduction to aspect ratios (DAR, PAR, SAR), and how to use that for resizing your clip. High bit-depth (Deep Color) support with AviSynth	Development Want to get involved? The official project. Learn how to install compilers and setup environments. Learn how to compile AviSynth, AviSynth plugins and console applications that access AviSynth. Learn how to debug AviSynth, AviSynth plugins and console applications that access AviSynth. Filter SDK – AviSynth plugin programming tips. Avisynth Plugin Development in C – A tutorial to write a plugin with C. AviSynth Developer Forum The ongoing changelist. About the development of AviSynth v3 (which will be platform independent). References to image processing algorithms.
About This Website We need your help to build and improve our site! Editing is easy! Please see Editing pages and Formatting. To port this site to another language, please see the MediaWiki Localisation Guide. Filter and script authors – please see Submit your Documentation on doom9.org, and the documentation template ExampleFilter.	Documentation Copyright AviSynth documentation is Copyright (c) 2002-2026 AviSynth developers and contributors. The contents of avisynth.nl is released under the Creative Commons Attribution-ShareAlike 3.0 License (CC BY-SA 3.0).