Movie Audio

Thread Starter

biferi

Joined Apr 14, 2017
177
I have the DVD of the Movie Robocop 1987.

I was going to make a Copy and put it on my 256 GB USB Stick to Watch it on my TV.

I use DVDShrink and it Asks me Witch Audio Track I want to Copy?

Now it has AC3 4.1 Audio and I know Dolby Surround is AC3 5.1 Audio.

Then they have DTS 5.1 Audio and I know this is Surround but DTS is the Competitor of Dolby.

When Robocop 1987 was in the Movies was it in 4.1 Audio?
 

nsaspook

Joined Aug 27, 2009
8,770
I always Thought Dolby was 5.1 so how can 4.1 be Dolby Surround?
It's called history. I'm a bit of a movie sound buff from the 70's.
Early 70mm 6-track mixes were actually 4.2 - 3 front, mono surround and 2 LFE channels. You can't encode 2 LFE channels into AC3 hence it becomes 4.1. Later 70mm 6-track mixes used a single LFE channel and split surrounds, the same configuration used in Dolby Digital 5.1 mixes today.
https://originaltrilogy.com/topic/Info-Alien-Anthology-Dolby-Digital-4-1-Surround/id/13986
 
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Thread Starter

biferi

Joined Apr 14, 2017
177
I think I Understand?

Dolby Surround is a Front Left and Right Channel and a Front Center Channel.
Then a Back Left and Right Channel and a Subwoofer.

This is Dolby 5.1 and the .1 is the Subwoofer.

And Dolby 4.1 is a Front Left and Right Channel and no Center Channel.
Then a Back Left and Right and a Subwoofer.

This is Dolby 4.1 and the .1 is the Subwoofer.

So when it comes Time to Hear the Center Channel the Front Left and Right Channels are Mixed together to Form the Center Channel.

So this is Simulated Dolby Surround am I Right on this?

And if I Understand it Right why did they just not Make Robocop 1987 in Dolby 5.1 or was Dolby 4.1 First?
 

nsaspook

Joined Aug 27, 2009
8,770
And if I Understand it Right why did they just not Make Robocop 1987 in Dolby 5.1 or was Dolby 4.1 First?
Because it was 1987 and analog optical encoded on 70mm film.
https://www.cbsnews.com/news/landmarks-in-dolby-stereo-films/
"Batman Returns" (1992)

Tim Burton's comic book actioner was the first film released in Dolby Digital. The process replaced the analog optical soundtrack with digital information imprinted on the side of the 35mm film print (although optical soundtracks were also printed in case the theater's digital decoder conked out).
 
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