If using the V-4EX and it's USB output with OBS Studio, you may notice that your 16:9 sources appear squeezed in the OBS preview window, as well as on your streams and recordings.
To fix this, left-click on your video source and a red transform outline will surround it. Next, right-click, and a menu will pop-up, go to Transform > Stretch to Screen, and left-click to confirm.
Your video will now stretch out to its proper aspect ratio.