How to use an older avisynth script in ffmpeg

[tyee]

I have an older avisynth noise reduction script I really like and want to use it with a current version of ffmpeg. What I don't know is if avisynth scripts themselves were/are 8 or 10 bit or was it just avisynth itself? I would like to use this script to re-encode a 4k 10 bit hdr source file to a new hdr 10 bit file. Is this possible? Please include what the command line may look like.

[sneaker]

What I don't know is if avisynth scripts themselves were/are 8 or 10 bit or was it just avisynth itself?

A mix of both.
AviSynth+ has "native" support for 10 bit.
AviSynth 2.6 and older only natively support 8 bits. But you can still encode to 10 bits with 2.6 by either:

• dither source to 8 bit (not recommended)
• use "hacked" stacked or interleaved 10 bit formats. Same quality as AviSynth+ native, just more complicated to use. E.g. you have to pipe to ffmpeg, not open directly.

http://avisynth.nl/index.php/High_bit-depth_Support_with_Avisynth

The rest depends on your script and plugins. You cannot expect to simply take an old script have it work as a 10 bit pipeline.

[tyee]

Is upgrading to avisnyth+ easy, just copy the new dll? Also, I think last year ffmpeg could not encode 10 bit internally, is it still the same?

[sneaker]

Is upgrading to avisnyth+ easy, just copy the new dll?

I would make a backup of the old AviSynth installation (mainly the plugin folder). Then uninstall the old AviSynth. Then run the AviSynth+ installer.
https://github.com/pinterf/AviSynthPlus/releases/latest

Also, I think last year ffmpeg could not encode 10 bit internally, is it still the same?

This is encoder and built depended. The most popular ffmpeg binaries (by zeranoe) now do support both 8 and 10 bit x264 and x265 encoding.

[tyee]

Ok, thanks. I decided to just copy the avisynth.dll's into where the readme.txt file said. I ran a version.avs file and it shows the proper version in Virtualdub2.

I copied all the 32 bit folders and files (including the plugins+) into a folder I created called "avisynth+" on my C drive.

The info on doom9 said "Avisynth+ uses a different C++ runtime, which needs to be installed separately", but did not say how to install this. It was in a folder called "c_api" and currently that's where it sits within my "avisynth+" folder. I assume that because the version command worked that all is correct?

Now how do I really test if avisynth+ is installed correctly? I will try loading a file in an avs script and see if it works.

Update - I'm editing the names of my plugins (renaming the filename but keeping script filename the same) to see if I get errors and I don't which seems strange. How does the new avisynth+ know where my avisynth+ folder/plugins+ folder are now? I assume I can use "plugins+" as a folder name and not have to remove the "+"?

Update2 - I have confirmed avisynth is using my old plugins folder because I renamed it and the file would not load into Vdub. So where do I change this?

Found it here - http://avisynth.nl/index.php/AviSynth%2B#Plugin_Autoloader
and here - https://video.stackexchange.com/questions/20753/how-to-change-avisynth-plugins-directory