The current state of the art subtitling for film is to use a laser subtitler
The laser subtitler operates on the final distribution copy and burns the subtitles into the video. This process is relatively slow and it takes a couple of hours to produce 1 hour of subtitled film. The Cavena Cinetitle system is produced for the Cinevator real time film printer. The Cinevator prints film from 2K or 4K video in real time. Originally the design was made to allow for the distribution of digital movie productions to cinemas that still use film projectors.
The Cinetitle system was designed to allow subtitles to be included during this process and without additional time added. While this is still true it has also been shown that the ability to subtitle in real time in itself is a so powerful feature that it will drive some sales for the system. An additional benefit of the system is that the graphical quality of the subtitles far exceeds the quality of laser subtitling.