Most Hollywood movies from the mid to late 1950s or early 1960s recorded all dialogue on set to mono analog 1/4" tape on a Nagra III then other Nagra models until around 1989 when Jeff Wexler (The Natural, ID4, Fight Club) first began using DAT to record dialogue on set.
Quote:
First movie I did with DAT was "Ghost" in 1989 on a SONY D-10.
Prior to DAT those 1/4" tapes often got printed to a piece of film so they could edit and sync sound to picture. Then all the scoring and other audio gets recorded and mixed with the dialogue, likely to analog tape or maybe just a film print for distribution. Some videos below illustrate the process a little.
https://jwsoundgroup.net/index.php?/topic/29225-the-first-film-made-with-digitally-recorded-sound/https://www.youtube.com/watch?time_continue=3&v=EgT4-gDaCNo&feature=emb_logohttps://www.youtube.com/watch?v=OjKQNykc_04&feature=emb_logoIn 1986 Sony introduced the D1 (component) digital video format and from then on "Digital Mastering" was possible. Prior to that it was likely 1" analog video tape. The D1 system allowed a SPDIF input so that the master contained digital audio. D2 (composite) arrived in 1988.
So technically speaking LD with a completely digital audio chain was not happening until 1989 at the very earliest and even then, Jeff was a Pioneer so it wasn't for another year or so before more mixers adopted that workflow. Even then, the DAT tapes *may* have just been transferred (via analog) to a piece of film as before the days of DAT because their systems had not evolved yet.
So, The Cotton Club in 1984 was almost certainly recorded to 1/4" analog tape (on set dialogue) so if the LD has PCM on it you should know that the source of the PCM is still analog.
Maybe some of that was useful....