Avisynth+

[ultim]

[MODERATOR EDIT:]
Current branch as of November 2019:
The pinterf fork was integrated in main line like AviSynth+ 3.4.0
Download and sources: From GitHub

Older superseded branch/fork:
[Download: From GitHub (use version with vc_redist when installing for the first time)
Sources: https://github.com/pinterf/AviSynthPlus]
[END MODERATOR EDIT]

Avisynth+ compared to Avisynth 2.6
- 64-bit version compatible
- Multithreaded
- High bit-depth support
- Faster script startup and substantially faster core filters
- Support for multiple ("shadow") plugin directories
- Autoloading of C-plugins
- Script language extensions, with support for multiline conditionals and loops.
- Improved still image support and TimeStretch
… and more to come as development continues

Avisynth+ features for developers
- Easy and fast compilation, with current compilers
- 2x increased compilation speed
- Improved debugging experience
- Leaner and more logical project structure
- Large parts of the code refactored
… and being continuously improved

How to install
Use installer for the latest release from here. If classic AviSynth is already installed, you will be offered the choice of either upgrading or replacing it. In the first case you'll be able to switch back to classic AviSynth by simply uninstalling AviSynth+. Your existing plugins will be kept in both cases.

Can I just replace the old avisynth.dll with the new one from AviSynth+?
Yes, with some caveats. In Avisynth+ some core plugins have been moved to external plugin DLLs (but are still shipped with the core), so you'll manually need to copy those too. Avisynth+ uses a different C++ runtime, which needs to be installed separately. And last but not least, this will make your Avisynth and Avisynth+ plugins mix in the same folders, which you might not want (though it is harmless ATM). All in all, I recommend you use the Avisynth+ installer instead, which will take care of all these problems for you.

Compatiblity to Avisynth
Avisynth+ tries to provide a superset of Avisynth's features while staying compatible to existing code. This means you should be able to use plugins and scripts written for Avisynth without any problems with Avisynth+. The contrary however might not be true: Plugins and scripts written explicitly to take advantage of Avisynth+ might not work using the official Avisynth.

Shortcomings compared to Avisynth
- Support for Windows 98/Me/2000 dropped. Oldest supported OS in Windows XP.
- TCPDeliver not included in the sources. However, TCPDeliver from official Avisynth can be used with Avisynth+.
- Ability to load VFAPI filters is missing, hopefully temporarily.

How to compile (without DirectShowSource)
- Get Git for Windows.
- Get CMake.
- Get Visual Studio 2013 Community Version.
- Clone the repository from GitHub.
- Configure the project using CMake. No manual changes to CMake variables are necessary, just hit Configure, select yout compiler then Generate.
- Load generated VC++ solution and compile.
- Done.
- OR alternatively to the above steps: For people who prefer to compile from the command line, qyot27 was kind enough to provide detailed compilation instructions from an Msys environment. See http://forum.doom9.org/showthread.ph...29#post1643929 .

This is a community project and you are welcome to work on improving Avisynth+. Let us know what you're working on either here or on #avs-plus on Rizon, and join the discussions. Feel free to work on any feature you'd like, or if you are feeling unsure where to start, choose an open issue from the GitHub page. Testing, documenting, and giving any kind of feedback is also a great help.

Avisynth Plugin Writing Tips Series
Tip #1: Exceptions
Tip #2: Parallel execution
Tip #3: Choosing your AviSynth header