Why use avisynth

The application, however, is not aware that AviSynth is working in the background. Instead, the application thinks that it is directly opening a filtered AVI file that resides on your hard drive. The simplest thing you can do with AviSynth is the sort of editing you can do in VirtualDub.

The scripts for this are easy to write because you don't have to worry about variables and complicated expressions if you don't want. Now open this file with e. Windows Media Player and you should see a ten-second video clip showing AviSynth's version number and a copyright notice. Version is what's called a "source filter", meaning that it generates a clip instead of modifying one.

The first command in an AviSynth script will always be a source filter. Reopen the file in Media Player. You should see the copyright notice again, but now half as large as before.

ReduceBy2 is a "transformation filter," meaning that it takes the previous clip and modifies it in some way. You can chain together lots of transformation filters, just as in VirtualDub. Let's add another one to make the video fade to black at the end. AviSynth is, in my humble opinion, the most significant addidition to Windows digital video editing in recent memory.

It it incredibly powerful and, once you get used to it, it is incredibly convenient for doing all kinds of wonderful video manipulation tasks that would be very difficult to do otherwise. There aren't any problems with AviSynth in my mind but there is a problem with the way it is perceived. Many people don't really know what it is, what it does or why any of this is actually useful.

Others feel that they don't need it because their method has worked for them and they are sticking to it Demystifying AviSynth AviSynth isn't a program in the way you may usually think of programs. You don't run an. AviSynth is a video processing machine that works in the background. All you do is write a simple file with some commands on it and you give this file to a Video Editing program to read. When the Video Program looks at the file it doesn't see the silly commands you wrote: it sees video.

The video the program sees is what you described in your simple file. Let me demonstrate the process by using resizing as an example: Take Video 'X' whose resolution is too small Make a simple avisynth script that says "This is a bigger verison of Video X" Give avisynth script to editing program Editing program looks at the script file and instead sees footage Every time the program looks at a frame, avisynth takes Video X, makes the frame bigger and then gives it to the editing program.

So, instead of having to make a brand new video which is bigger than the old one, AviSynth simply makes each frame bigger when the editing program wants to see that frame.

This all happens behind the scenes so that the effect is that you have your bigger video but no need to re-encode or make a new file. Of course this sort of thing you can do in your editing program - you can tell the editing program to scale up the footage.

This is just the start though - you can put all sorts of commands in these scripts such as: Take some dvd footage that an editing program can't read Decode it Look for the Telecine interlacing pattern Restore the original frames and remove interlacing Trim out a scene Crop off the junk from the edges Filter the footage so it looks cleaner Change the frame rate Give it to the editing program And all of this can be done before the video program even sees the footage - and all in one place.

You don't need one program to decode the dvd footage, then another to remove interlacing and then another to make it look better. AviSynth does all these things and a LOT more besides all in a simple script file that you write. AviSynth has become essential to Windows digital video editing because of this flexibility and also because of its immense power. The kind of deinterlacing and telecine removal that you can do in avisynth is something that you could potentially pay thousands to do as part of your professional video editing program.

The ability to decode mpeg2 is something that many editing programs have these days but few can do it quite so accurately as AviSynth. Combine this with its ability to convert types of footage, and do all the other digital manipulations it does, then it's easy to understand why this is such as useful tool.

And all of this is done in a mere few lines of text. That's the real beauty - you need to change something, you change the script. You want to add something else, you add it to the script. It's convenience in excess Getting Avisynth to do its thing. Avisynth uses scripts which you have to write and it is these scripts which tell avisynth what to do and what video to produce when this script is given to a video editing program. 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 Official builds v. Homepage avs-plus. Known Issues in v2. 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. 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.

Or you can jump straight to pages listed below for downloading Avisynth.