What are or where to find SDI record start/stop ancillary packet specification for Sony, Red or Panasonic
I couldn't find specific details, but it appears that ancillary data on SDI in general conforms to SMPTE 291M.  I couldn't find any details about the specific implementations used for deck control.  It appears like there could potentially be some variation between manufacturers or even particular decks since the ancillary space doesn't seem to be that regulated other than specifying what it shouldn't step on with the main signal.