A truly standard-compliant preview on the laptop is offered by an external, dedicated preview box, which is available from companies such as 
AJA or Blackmagic Design. These are usually connected to the laptop via Thunderbolt and provide SDI and HDMI signals as well as several audio connections.
Blackmagic has raised the driver collection for its own video capture and playback cards to version 12.0. And with this version jump, the new Macs with the M1 processor are now also supported. This is exciting because until now there was no way to get a preview out of the new M1 Macs that guaranteed a 100% correct signal output - such as a 10-bit REC709 YUV preview at 50 Hz.
The entire driver package supports the DeckLink, UltraStudio and Intensity solutions under Windows, Linux and Mac, although there are some limitations under MacOS 11.0 Big Sur. For example, not all models are supported by the new Macs. The following list gives a detailed overview of the models with which the M1 Macs also work:
Supported cards for M1 and Intel Macs:
DeckLink Duo 2
DeckLink Quad 2
DeckLink Quad HDMI Recorder
DeckLink 8K Pro
DeckLink 4K Extreme 12G
DeckLink Micro Recorder
DeckLink SDI Micro
DeckLink Mini Monitor 4K
DeckLink Mini Recorder
DeckLink Mini Recorder 4K
DeckLink SDI 4K
DeckLink Studio 4K
UltraStudio Recorder 3G
UltraStudio Monitor 3G
UltraStudio HD Mini
UltraStudio 4K Mini
UltraStudio 4K Extreme 3
Intensity Pro 4K
DeckLink 4K Pro
DeckLink 4K Extreme
UltraStudio 4K
UltraStudio 4K Extreme
Only supported on Intel Macs:
DeckLink Mini Monitor
DeckLink HD Extreme 3
DeckLink HD Extreme 3D
DeckLink SDI
DeckLink Duo
DeckLink Quad
DeckLink Studio
UltraStudio Express
UltraStudio Mini Monitor
UltraStudio Mini Recorder
Intensity Pro
Intensity Shuttle Thunderbolt
The list of supported applications is also much shorter for the new Macs:
M1 Macs:
DaVinci Resolve 17.1 beta.
Fusion 17.1 beta.
Apple Final Cut Pro X.
Adobe Premiere Pro 2020 beta.
Photoshop 2020 beta.
Intel Macs:
DaVinci Resolve 16 and 17 beta.
Fusion Studio 16 and 17 beta.
Apple Final Cut Pro X.
Adobe Premiere Pro CC 2019 and 2020.
Adobe After Effects CC 2019 and 2020.
Adobe Photoshop CC 2019 and 2020.
Adobe Character Animator CC 2019 and 2020.
Autodesk Flame 2021.
Avid Media Composer 2020.
Avid Pro Tools 2020.
The Foundry Nuke.
