First, the https://www.startech.com/en-us/audio-video-pr … ts/usb32dvcapro does not appear to support direct analogue VGA capture based on comments from Startech support someone (they suggest the USB3HDCAP instead for that, but that is not without it's challenges for capturing DOS game footage, see https://nerdlypleasures.blogspot.com/2018/02/ … cap-review.html ).
EDIT: Manual ( https://media.startech.com/cms/pdfs/usb32dvca … o_datasheet.pdf ) says : "This versatile DVI capture device works with HDMI to DVI and VGA to DVI adapters, so you can record video from an HDMI or VGA source"
EDIT: Someone mentioned this device working for direct VGA capture under DOS, but that was in February 2019 and, while it says "verified purchase", I am not convinced the product sold was the same as the one currently sold there.
a) Does your 486 have a VGA card with DVI output (that is uncommon)?
b) Are you using an adapter or converter to DVI between the VGA output and the capture device ? If so, please specify?
c) How is the XP machine's output connected to the capture device (adapter or converter, directly over DVI, etc)?
EDIT : d) What is the video card in the 486 ?
Your usb32dvcapro MIGHT possibly have undocumented (and unsupported by the manufacturer) analogue VGA capture functionality, but that is quite unlikely.
eckman wrote on 2025-07-03, 17:59:
Any way to force resolution to 800x600 within DOS command prompt?
That will depend on the video card in the 486 and the resolutions and refresh rates it supports. You could possibly use a mode set utility to possibly get a DOS prompt in a higher resolution, but this will not help with capturing video of most DOS games, because they will reset the output to whatever VGA mode the y want to use. 800x600 is not a VGA resolution. VGA tops off at 720x400@70Hz in its text mode (which is what DOS uses by default) and, in terms of graphics modes, 640x480@60Hz in 16 colors and 320x200@70Hz in 256 colors, which the VGA cards line doubles to 640x400@70Hz.
Most VGA DOS games run at 320x200@70Hz, which the VGA cards line doubles to 640x400@70Hz and that is what your capture device would need to support to work with games. Capture devices can sometimes be more flexible that what their official specs imply in terms of refresh rates (more likely with higher end devices like the usb32dvcapro, but not guaranteed), so 640x400@70Hz might maybe work with a usb32dvcapro IF the signal is converted to DVI before being fed to the usb32dvcapro. This would require an active digitizer and/or scaler, like an OSSC or an Extron RGB-DVI 300 (As examples) to digitize the signal and optionally scale it (if your capture device actually requires 800x600, the OSSC will not suffice, an Extron RGB-DVI 300 would work) BEFORE feeding the resulting DVI signal into your capture device.