
Some BM devices do have hardware-based up/down converters. Check the spec's page.
For example, the UltraStudio 4K Extreme 3 has it. It can downconvert UHD to HD via SDI C and D. SDI A, B and HDMI will remain UHD.
https://www.blackmagicdesign.com/produc ... /W-DLUS-09