Copy-paste of some links that explain how is possibile to achieve HDR video footage.
1.alternate pixel exposure sensor
Used in the Google pixel phone camera( Sony sensor)
Explanation links:
https://www.xda-developers.com/sony-imx378-comprehensive-breakdown-of-the-google-pixels-sensor-and-its-features/
2.Piecewise Linear Response sensor
Used in the open source camera Axiom alpha
https://www.apertus.org/node/326
Explanation link:
https://www.ximea.com/support/wiki/allprod/HDR_mode
There is Magic Lantern for certain Canon cameras, with which you could use Dual ISO on stills and video. Basically, you have alternating lines of lower and higher ISOs. This increases the dynamic range of your image or video. The downside is that the resolution in the brightest and darkest areas is halved.
I don’t use it anymore because it messes up my photos’ embedded previews and takes more work to process. One extra step really but still; i.e. cr2hdr.
ML also allows you to record in raw video, which would allow you to push the image as you would a still. I haven’t experimented with this or Dual ISO video because my camera is entry level and doesn’t have the processing power.