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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 tedious 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.

Interested? Download AviSynth from one of the links below, then scroll down to New to AviSynth - start here!

AviSynth is free open-source software, under the GNU General Public License version 2.0 (GPLv2)

Official builds

NOTE the recommended download for almost everybody is v.2.6.0 ST, 32-bit. 'Still in alpha stage' refers to the new 2.6.0-specific features only. Avisynth 2.6.0 is actually more stable than 2.5.8 in almost all cases.

• v.2.6.0 ST, 32-bit at SourceForge (still in alpha stage)

• v.2.5.8 ST, 32-bit at SourceForge

Unofficial builds

• v.2.6.0 MT, 32-bit, author SET at forum.doom9.org

Forks

• AviSynth+, 32-bit and 64-bit, author ultim at forum.doom9.org. Download avs-plus.net.

• AvxSynth: a Linux port of AviSynth AvxSynth is a native port of AviSynth 2.5.8 running on Ubuntu 32/64.

Deprecated

• 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

Bugs and issues

A list of bugs which are present in v2.5.8 and 2.6a5: Known Issues. Most of the 2.5.8 issues are fixed in v2.6a5.

Usage

New to AviSynth - start here

• Your first script - A guide for total newbies.
• Getting started - An introductory guide for getting started with AviSynth.
• Script examples - Assorted examples for putting everything together in the real world.
• Filter introduction - An introductory guide to most common AviSynth filters.
• Some guides explaining the basic possibilities of AviSynth:
  • Analog Capture guide. The AviSynth part of the capture guide is about what filters can be used to enhance the quality of the capture. It discusses things like deinterlacing, denoising, cropping and resizing and color adjustment. Which makes it really useful to learn about some of the capabilities of AviSynth in a schematic way.
  • AviSynth 101 mirror - A guide by l33tmeatwad, it includes mostly current information on software setup, video basics, importing videos, handling audio, using filters and other useful information.
  • Introduction AviSynth from AnimeMusicVideos.org. A basic guide about deinterlacing, resizing and some other basic stuff.
  • Introduction basic AviSynth filters from AnimeMusicVideos.org. A basic guide about smoothers, rainbow removal, sharpeners, color adjustment and some other basic stuff.
• Troubleshooting your scripts and configuration.
• Read more about AviSynth (How does it work? When is it useful? Why no GUI? What applications work well with Avisynth?)

Filters, external plugins, script functions and utilities

• Internal filters - The official list and descriptions of included filters, organized by category.
• External filters - Documentation of custom script functions and AviSynth v2.5x and v2.6 plugins.
• User pages hosted on this site:
  • AviSynth Filter Collection - Warpenterprises
  • 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.

AviSynth Syntax

• AviSynth Syntax - The official reference documentation.
  • Grammar - The grammar of AviSynth script language. An introduction to AviSynth scripting.
  • Internal functions - Ready-made non-clip functions to use in scripts.
  • Script variables - How to declare and use them in scripts.
  • Operators - Available operators and relative precedence.
  • Clip properties - Functions that return a property of a clip.
  • Control structures - Language constructs for script flow control.
  • User defined script functions - How to define and use them in scripts.
  • Plugins - How to load plugins (AviSynth, VirtualDub, VFAPI and C-plugins), autoloading and name-precedence.
  • Runtime environment - Scripting on a per clip frame basis.
• Scripting reference - Beyond scripting basics.
  • 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.

AviSynth FAQ, Guides and Advanced topics

• AviSynth FAQ - Answers to many common problems.
• Aspect ratios explained - Introduction to aspect ratios (DAR, PAR, SAR), and how to use that for resizing your clip.
• Guides - Tips on specific conversion types and common tasks.
• 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.
• High bit-depth (Deep Color) support with Avisynth

Development

• Want to get involved?
• The official project.
• 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.

AviSynth Wiki

Welcome to our MediaWiki. Feel free to pitch in and help out! We need your help to fill and improve our Wiki. Please see Localisation and the User's Guide for usage and configuration help.

AviSynth documentation copyright

AviSynth documentation is Copyright (c) 2002-2015 AviSynth developers and contributors.

Starting from 5 August 2007 the documentation on this site (avisynth.org and avisynth.nl) is released under the CreativeCommons Attribution-ShareAlike 3.0 License (abbreviated by "CC BY-SA 3.0", see also full license terms). More information can be found here.