Installing Vapoursynth

09 Apr 2022 • Vapoursynth Scripting

It’s been 2 years and one day since my first post here and I’ve done far less than I intended. This is mainly due to my inability to write something that I am happy with, and so most posts get deleted. Still, I am interested in writing about things, and people still ask me the same questions over and over, so it would make sense to write a blog post to link those people to. Like this question, for example.

How do I setup Vapoursynth?

I could just do the braindead answer and link to the docs, which would make some sense, after all, these are the official installation instructions, but they aren’t particularly helpful past getting Vapoursynth on your machine, and the applications list is well out of date at this point (vsedit is now completely broken - F). So, in this post, I’ll cover how I would set up a new machine for Vapoursynth script development.

I assume at least a basic understanding of the command line for most of this tutorial, but for those who are new to this, if I say “run x,” I generally mean on the command line. This can be accessed by Powershell (recommended) or cmd on windows. To open Powershell, use Win+X, and select “Windows PowerShell.” For further reading, the mozilla docs are pretty good.

Prerequisites

  • Windows 10/11

    It’s not like Vapoursynth doesn’t run on linux distros or MacOS, I just don’t have a Mac, and there are too many linux distros to cover. Many of the most popular ones have Vapoursynth on their respective package managers. If you are really struggling, contact me and I can probably help.

  • Python 3.9

    I hate python. I can never seem to get it to play nicely with anything. Probably a me thing. My suggestion for installation is to run the installer (as admin), customise installation and select “for all users.” Vapoursynth can be installed for just the user, but it’s caused me problems in the past, and I know that this just works™. Also make sure to select pip so you don’t have to grab it later.

    I would suggest making sure all old Python installations are gone before installing 3.9. You can have multiple python installs, and it can work, but I can’t ever get it to, so you’ll be on your own.

    As of today, the latest release of Vapoursynth (R57) supports 3.9. You can compile it yourself for 3.10, but that’s outside of the scope of this post. I will update the post when this changes.

  • Visual Studio Code

    Any code editor with a built in terminal will work (for example, Atom), however I use vscode myself, so will be using that for this guide.

    Make sure to install the Python Extension!

  • pip

    Not strictly necessary, however many packages are hosted on pypi, and pip just makes installation of them easier. If you forgot to install it with Python earlier, run python -m ensurepip.

  • git

    Also not necessary, but makes installation of packages not on pypi (like EoEfunc) easier to get.

Vapoursynth

Vapoursynth R57 can be downloaded from here Run the installer as administrator, and just leave everything selected. Afterwards, go to the console and run python -c 'from vapoursynth import core; print(core.version())'. You should get details of your Vapoursynth installation printed to the console. If not, something’s gone wrong.

Plugins / Scripts

Vapoursynth can be used as is, vspipe should now be in your PATH (i.e. you can run vspipe), so you can run a basic script, however you’ve got no extra plugins or packages, nor any way to preview your outputs. You can browse VSDB for many plugins/packages that you might want, but if you just want a quick way to download basically all the stuff you’ll ever need, feel free to use the Judas Vapoursynth Install Script. To run, just extract it, and then right click on install.ps1 and click “Run with PowerShell.” Assuming you installed Python/Vapoursynth as described above, you should be able to leave the installation paths as they are (hit enter twice).

Note that this is an internal Judas install script, so some of the stuff in here is held at an older version than is available for compatibility reasons (e.g. lvsfunc, vardefunc). These can be upgraded manually via pip should you wish to. It also assumes you have all the prerequisites above (except vscode) installed already.

Previewing

Next, I’d suggest installing some way of previewing your scriots. My favourite previewer is Endill’s Vapoursynth Preview. He hasn’t yet upgraded it to work with the latest Vapoursynth version, so I’d suggest using Akarin’s fork. To install, open the folder you want vspreview to be in (I use C:\PATH, but anywhere works), hold shift and right click in the folder, and click on “Open PowerShell window here.” Now run git clone https://github.com/AkarinVS/vapoursynth-preview.git. This will copy all the files from the git repository into a new folder called “vapoursynth-preview.”

Now, we need to add vspreview as a launch configuration in vscode. Open vscode, and press F1, then type “Preferences” into the search bar. Click on “Preferences: Open Settings (JSON)”. Paste the following into the file that opens, replacing the “program” path with wherever you installed vspreivew. Make sure to use double backslashes in the path so it doesnt break!

{
    "files.associations": {
        "*.vpy": "python",
    },
    "launch": {
        "configurations": [
            {
                "args": [
                    "${file}"
                ],
                "console": "integratedTerminal",
                "name": "Vapoursynth: Preview",
                "program": "C:\\Path\\To\\vapoursynth-preview\\run.py",
                "request": "launch",
                "type": "python"
            },
        ],
        "version": "0.2.0"
    },
}

Now you should be able to press F5 to preview whatever script you currently have open. Any easy test for this is below, save it as test.vpy and try pressing F5. You should get a window open with a red frame. I’ve also included a file association for vpy to python so that you get syntax highlighting.

My full vscode settings are available here, though I warn you, it’s not organised and half the settings in there are old. If you do use them, you should also install Pylance, black (pip install black) and flake8 (pip install flake8), as well as Fira Code.

import vapoursynth as vs
core = vs.core

core.std.BlankClip(color=[255, 0, 0]).set_output()

All done!

Hopefully this has been helpful for anyone trying to setup an environment to start learning Vapoursynth. Eventually I’ll write a proper post on learning to write scripts without it being too hand holdy like my initial attempt. If you run into any issues, my dm’s are always open (End of Eternity#6292).

Cheers, EoE

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