Camera original formats will maintain the most quality, but they are also often partially proprietary (even if they lean heavily on on the MXF standards, there always seems to be some proprietary extras mixed into the files on formats like XDCAM and P2). In all likelihood the essence video in these MXF camera formats will be playable long into the future owing to the MPEG codecs they employ. You need to be a little more cautious if you are dealing with strictly proprietary codecs like ProRes or DNxHD. These formats could one day become open standards, but only by the graces of Apple or Avid, respectively.
Unfortunately the nature of all file based content is relatively ephemeral since codecs change and improve over time. Then you compound that with how computer filesystems change and improve over time as well. Realistically, you can’t expect to encode some video to a contemporary codec and have that be a common codec a couple decades from now. You’re confronting an issue the industry is still at the beginning of trying to solve, so I recommend storing the camera original data along with perhaps an H.264 high bitrate proxy, but there are no guarantees.
The safest physical layer for the data would be an open-format LTO (the open formats for LTO being TAR and LTFS).
Best,
Andy Richards
VP of Product Development
Keeper Technology