SGI Video capture with Magewell USB Capture DVI+


Storybook / Retired, ex-staff
Feb 4, 2019
Mountain West (US)
I bought a Magewell USB Capture DVI+, which supports DVI, VGA (with Sync-on-Green), HDMI, and Component. The idea is to not require another physical monitor for my SGI, but instead display the video output in a window on my regular desktop, as well as enable recording the video output. I picked the Magewell device as the control software looks good, it came with detailed hardware specifications for video input, and it supports OS X (which notably the equivalent and more expensive Epiphan device does not).

In summary, the device works with SGIs, more or less.

Oddly the PROM monitor screens are pink, which could be related to the dip switch settings on my 13W3 to VGA adapter:

However, once it boots into IRIX all is well:

Lag from input to video display on the host system is not too bad at all; I probably wouldn't want to compete in Descent II with it, but it works fine for regular usage.
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Active member
Jul 22, 2020
Usually I use OSSC for convert vga from SGI to HDMI and capture with a simple HDMI capture stick. OSSC support sync on green.
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Dec 13, 2022
Just wanted to share a video capture setup that worked for me:
Octane –> 13W3-to-VGA dip switch cable –> Magewell USB Capture AIO –> OBS Studio (OS X)

First I tried all my VGA/DVI cables with VGA-13W3 adapters. They work perfectly with SGI and other SoG-capable monitors, but cannot sync when captured. So I ordered a 13W3-to-VGA dip switch cable and it provided perfect sync with Magewell in all pin configurations for SGI (check the table in the first post here

Another minor problem was with the pink tint which was easily resolved with the Magewell settings. Just change the video input color format to RGB and that's it.

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