No, this is not a feature request. More of a FYI post, really.
I requested support for VapourSynth once. It got denied. Which is fine, as you can still use VapourSynth, only indirectly. Let me introduce you to the AV FileSystem What this does, is allow you to mount a VapourSynth script in the filesystem, so it appears as a real, uncompressed avi file, which you can then simply browse for with TVAI.
Why is this so important, you ask? For me, because I have been plagued with TVAI’s dismal denoising techniques. Problem is, the A.i gets in the way, it seems. Sometimes it thinks the noise actually is something useful (and then does something dreadful with it), and sometimes it decides the noise is just noise (to paraphrase Freud). So, a custom, pre-pass, quality denoiser (such as they exist in VapourSynth) was really needed for me.
Works something like this:
PS D:\jobs> cmd
Microsoft Windows [Version 10.0.22621.1105]
(c) Microsoft Corporation. All rights reserved.
D:\jobs>avfs.exe f:\jobs\test.vpy
Mount point: C:\Volumes\test.vpy
Press CTRL+C to exit.
Now you can let TVAI browse to your mounted movie (now a virtual .avi), and let TVAI do its thang. AVFS comes prebundled with VapourSynth itself.
Happy rendering! 
