So, this is interesting that I haven’t noticed this. There are cue marks on movie films? Traditional movie film reels are 14 to 20 minutes in length, so a full feature-length film must be delivered on multiple reels of film. Inside a projectionist’s booth, there would be two movie projects set up side-by-side: one to display the actively running film, the other one to queue up the next reel in preparation for the switchover. The projectionist would watch the upper right hand corner of the running film for a first burnt out dot to flash. This would indicate to them that it is time to start the motor on the second projector, with the film running starting at 8 seconds of countdown. Then there would be a second burt out dot flash a 7 seconds later. One second later the projectionist would execute the switchover.
So, that says a lot about the old days of film and cinema. Yeah, it definitely wasn’t as easy to run a movie theater back then as it is today. In the last generation of film before the digital switchover, there was an alternate projector design that could run off of one really big long reel of film, thus not requiring switchovers through three or more separate reels of film to show a movie. Today’s digital cinema knows of none of the problems of running a cinema in time’s past. Heck, modern digital theaters don’t even need a human at all at the projector.
Interestingly, cue marks were also used in analog television. However, they are no longer used in digital television due to the time delays (sometimes delaying by a seconds) caused by the digital compression encoding process. In general, with digital media, out-of-band signaling is used.
20190326/https://en.wikipedia.org/wiki/Cue_mark
Coded anti-piracy, some of the codes used on movie film reels in order to make illegal copies more traceable. Some of the codes resulted in significant visual quality deterioration. Similar codes have found their way into digital cinema.
20190326/https://en.wikipedia.org/wiki/Coded_Anti-Piracy
These are some interesting articles classifying the various bootleg techniques used to make illegal copies. Telesync = audio and video synchronized duplication via camcorder. Cam = unsynchronized duplication via camcorder. Telecine = the professional video recording duplication technique, but in the case of bootleg, being used for illegal purposes.
20190326/https://en.wikipedia.org/wiki/Telesync
20190326/https://en.wikipedia.org/wiki/Cam_%28bootleg%29
20190326/https://en.wikipedia.org/wiki/Screener_%28promotional%29
These are interesting security codes found on currency. EURion constellation = a pattern of circles that is easy to detect to prevent counterfeiting. Digimarc barcode = a more concealed proprietary barcode format used to prevent counterfeiting.
20190326/https://en.wikipedia.org/wiki/EURion_constellation
20190326/https://en.wikipedia.org/wiki/Digimarc