[A full treatment of this to Ic would be very long. (See https://en.wikipedia.org/w/index.php?search=Video+recording&title=Special:Search&profile=default&fulltext=1&searchToken=dsltudxevib7ou90v33eoj7l6.) What follows is the question of format as seen by the pornographer and the pornography collector. While I never produced video pornography — I am doing some small scale audio porn —my masturbation addiction, of which I’m proud, and the resources I had as a professional, meant I could buy each format of pornography as it vanquished the old. — TakkUser:aanker
Home pornography was born around 1979, with the commercial launch of the home video recorder, which used cartridges of 1/2" magnetic tape in two formats, the triumphant VHS (Video Home System), and the technically superior Beta, used only by the brand Sony, which captured a significant market share., 2 inch and 3/4 inch video recorders are earlier, but they were too expensive for home use and a content industry in those formats never arose, The videodisc (12" discs) was popular in the 1990s, and for a few years it was routine for major mainstream studios to release movies in that format if they were released in VHS.
8 milimeter film was used on a small scale for porn. It required in most cases that the pornographer set up his own film developing facility, as sending it to a commercial lab would mean sure incarceration. Old Reliable (David Hurles, http://en.wikipedia.org/wiki/Old_ReliableZ) did that. Pornographers tended to be friends with each other — many of them fucked each other, or shared younger “models” — and there are isolated cases of shared darkrooms. (Film developing required a dafk room, which could only be illuminated with a pale rec light, red being the color photographic film is least sensitive to. I had my own darkroom in high school; my parents gave me the equipment. Unfortubately, dick pics, I learned the hard way, were not of much interest to students in the early 1960s.