2020-12-07, 09:56 PM
I think I read this whole thread close enough but I'm probably repeating somethings.
Dolby had been working on various digital systems long before DTS. One such system was to actually to replace the optical tracks with digital encoded tracks, before even CDS, that would be de-matrixed into 4.0/4.1. There were a lot of attempts to have discrete sound on 35mm like CDS and a laserdisc system (LC Digital) suspiciously close to what DTS became. It wasn't till DTS started picking up steam with Spielberg and Universal coming on board that Dolby started pushing up their plans.
Dolby Digital is kind of all of those terms at once. It is AC-3, Spectral Recording - Digital (SR-D), Dolby Stereo Digital and Dolby Digital. Internally it was called AC-3 (there was an AC-1, AC-2 and AC-4) but that was never meant to be a marketing term or for use with the public. But we laserdisc guys love our terms so it got stuck on there against what Dolby wanted. You rarely ever see AC-3 referenced in 35mm theaters.
Technically, for Dolby's discrete system on 35mm, the process started out being called Dolby Stereo Digital:
DS-D
That is what the branding of the system was at the start but not the only branding. As said before the designation Spectral Recording Digital (SR-D) means that the print has analog SR opticals and a digital track also. Both of these terms, DS-D and SR-D are almost the same since any Dolby Stereo Digital would have optical tracks backups and those most likely would be SR. As most Dolby optical tracks after say '88 were SR. I found some references to SR-D logo mostly being featured on Disney/Touchstone/Miramax/etc films (like Goofy) till the DD rebranding in 95-96. Outside of Disney, it seems other studios used the SR-D logo with films that primary had a DTS track and were marketed as such. But I can't confirm that 100%.
(Of course there are many exceptions and odd things like Jurassic Park being Dolby-A)
So when you see those terms they are basically interchangeable. There are fine points of difference and maybe how you are marketing or DTS but effectively they are the same. Dolby rebranded the whole system in the mid 90s to just Dolby Digital.
DD
Some logos here:
🔍https://logos.fandom.com/wiki/Dolby_Stereo
🔍https://logos.fandom.com/wiki/Dolby_Digital
Also there were always rumors that Star Trek 6 was the first "test" DS-D film with 2 specials prints made.
Dolby had been working on various digital systems long before DTS. One such system was to actually to replace the optical tracks with digital encoded tracks, before even CDS, that would be de-matrixed into 4.0/4.1. There were a lot of attempts to have discrete sound on 35mm like CDS and a laserdisc system (LC Digital) suspiciously close to what DTS became. It wasn't till DTS started picking up steam with Spielberg and Universal coming on board that Dolby started pushing up their plans.
Dolby Digital is kind of all of those terms at once. It is AC-3, Spectral Recording - Digital (SR-D), Dolby Stereo Digital and Dolby Digital. Internally it was called AC-3 (there was an AC-1, AC-2 and AC-4) but that was never meant to be a marketing term or for use with the public. But we laserdisc guys love our terms so it got stuck on there against what Dolby wanted. You rarely ever see AC-3 referenced in 35mm theaters.
Technically, for Dolby's discrete system on 35mm, the process started out being called Dolby Stereo Digital:
DS-D
That is what the branding of the system was at the start but not the only branding. As said before the designation Spectral Recording Digital (SR-D) means that the print has analog SR opticals and a digital track also. Both of these terms, DS-D and SR-D are almost the same since any Dolby Stereo Digital would have optical tracks backups and those most likely would be SR. As most Dolby optical tracks after say '88 were SR. I found some references to SR-D logo mostly being featured on Disney/Touchstone/Miramax/etc films (like Goofy) till the DD rebranding in 95-96. Outside of Disney, it seems other studios used the SR-D logo with films that primary had a DTS track and were marketed as such. But I can't confirm that 100%.
(Of course there are many exceptions and odd things like Jurassic Park being Dolby-A)
So when you see those terms they are basically interchangeable. There are fine points of difference and maybe how you are marketing or DTS but effectively they are the same. Dolby rebranded the whole system in the mid 90s to just Dolby Digital.
DD
Some logos here:
🔍https://logos.fandom.com/wiki/Dolby_Stereo
🔍https://logos.fandom.com/wiki/Dolby_Digital
Also there were always rumors that Star Trek 6 was the first "test" DS-D film with 2 specials prints made.