Thanks a lot for your reply ; as I wrote, Vista SP2 32-bit here; from 2016-2018 I used to use MABS (MSYS2/MinGW) to compile locally non-free ffmpeg builds; after that time, several MSYS2 components went Win7+ (e.g. "make") and by 2021, the compiler itself stopped being available for the 32-bit architecture; needless to say, latest MABS is meant for a recent version of Win10 64-bit; yes, you probably can still compile 32-bit binaries with it, but those won't run on Vista, possibly not on Win7, too ...
The AnimMouse ffmpeg builds used to be Vista-compatible, but broke at some time (early 2022); as a Vista user too, you probably know those things already ...
I'm not closely following current FFmpeg development ; at one time I was aware that the FFmpeg code itself continued to be NT 6.0 compatible (as opposed to NT 5.x), so that a "no-libs" compiled binary would launch normally under Vista; but a lot of the third party (external) libs built normally into FFmpeg are the main culprits for breaking Vista-support (x265 comes to mind, with its NUMA Win7+ functions ) ; it must be quite an enormous task today for you to restore NT 6.1/6.0 and even 5.x support on your custom FFmpeg builds; you are to be highly praised for this feat ...
On a 32-bit, under-resourced (by today's standards ) machine, I practically have little use of most of those extra libs (especially video encoders); I rarely do video transcoding here, mostly audio transcoding is being performed; it's those many optional external libs that inflate static binaries' filesize and are the cause for broken NT 6.0 support, for all I know...
Thanks for your intention! User Reino here (now on Win11) used to offer both static+shared 32-bit builds, targeting WinXP SP3 and an SSE-only CPU, ca. every 4 months ; it'd be very sweet from you if you managed to offer something similar, but for more recent CPUs (e.g. SSE2+) and on Vista+...
FWIW, this thread started a long while ago and mentions "winxp" in its title, but is actually frequented now by members of various WinOSes ; so I hope you posting Vista+ FFmpeg builds will be OK ; of course, there's always that ...
"Willing to test? " -> Simply throw "them" at me ...
Best regards.