To get back to the original subject of this post, I recorded a video (1920 x 1080 progressive) of a scan on the camera card (Nikon D5200).
I then played it from the camera and captured the scan through the HDMI capture card.
I check the images in "SL-Testsequence" folder. Everything ok., but the result was very bad. See images with gorilla with stripes.
I also tried to play the video on the PC using a virtual webcam. I could grab the video in David but the result was even worse.
David does some kind of "magic" with the live stream.
I have added another image for comparaison (with matchbox). This is grabed live from the Nikon with the HDMI capture card. I think this is excellent.
I wish the Nikon was mine
Panasonic GH4 4K with lens 12-35, Inogeni 4K to USB3 hdmi capture device, projectors: Acer K135/Acer K11/NEC V260X, Canon 60D, macro 60 mm, MagicLantern