From Canon USA:
Future Firmware plan to support advanced video recording functions for EOS-1D X Mark III and EOS R5.
In response to feedback from our customers about the EOS-1D X Mark III and the EOS R5, Canon U.S.A., Inc. plans to introduce the following video recording functions via a series of future firmware updates.
EOS-1D X Mark III
- Canon Log 3 option will be added.
- A low bit rate option for 5.5K RAW video recording will be added.
- A low bit rate option for all the IPB video recording modes will be added.
EOS R5
- Canon Log 3 option will be added.
- A low bit rate option for 8K RAW video recording will be added.
- A low bit rate option for all the IPB video recording modes will be added.
- A 119.88 fps option for Full HD (1080p) recording will be added.