Difference between 5.1 and 5.1 discrete

[tom_lowe]

Well according to Dolby's own website (I assume they know a thing or 2 about this) Dolby Digital is discrete.
Dolby® Digital, also referred to as AC-3, is an advanced audio encoding/decoding technology that efficiently delivers up to 5.1 discrete channels of vibrant surround sound for broadcasting, home cinema, cinema, PC, online streaming, and video game programming.

As for LtRt, ProLogic 2 will unfold it to 5.1.

[garnoil]

In my opinion, If I deliver 6 individual audio files that correspond to LCRLsRsLFE, I call this "discrete". If I deliver an AC3 file, I cal it...AC3 (I do not call AC3 discrete). The Dolby Digital website refers to AC3 as discrete because the "receiver" will unfold the AC3 (decode to AC3) into the original "format" LCRLsRsLFE BUT...without the receiver to decode the AC3, the AC3 is useless. The 6 original "discrete" files (LCRLsRsLFE) do not need a decoder to unfold to anything because they are "discrete". Also, the 6 original "discrete" audio files (LCRLsRsLFE) can be edited separately and recorded to tape, as in HDcamSR or even out of a mixer after conversion from digital to analogue to any type of tape. The AC3 can not be edited (you can not for example lower the volume of the C track) and is not intended to be a format that can be recorded to tape.

Saying that the AC3 is "discrete" would be the same as saying that the LTRT is also discrete because LTRT also unfolds to multi-channel audio playback.

[lexaudio]

I think the confusion here is file delivery versus physical channels.

AC3 is 6 discreet channels of audio. The file is not 6 discreet files.

LTRT isn't discreet. You have Pro Logic 1 which folds the surrounds into mono, and phase flips the center into the left/right so when it unfolds, there is som ein the LR.

Pro Logic 2 I believe they have been able to keep the surrounds separate and redeliver the sub channel.
NOt sure on this, but I know its much better, though it still isn't discreet.

Bottom line is 5.1 and 5.1 discreet are the same thing. IF you have 6 files that make up 6 discreet channels, or a DTS file, Dolby E file or AC3 file, you have 5.1 discreet channel playback.

Unless you are a mom and pop shop who does layback as well as mixing, no one is ever going to ask for a Dolby E, or AC3 file.

if asked for a 5.1 or 5.1 discreet, they are asking for the same thing.
2 track or 2 track folddown (the ltrt) comes with the delivery as well.

Now, if they want a 5.1 interleave. That could be on the next batch of deliverables.

[minister]

Originally Posted by tom_lowe

Well according to Dolby's own website (I assume they know a thing or 2 about this) Dolby Digital is discrete.
Dolby® Digital, also referred to as AC-3, is an advanced audio encoding/decoding technology that efficiently delivers up to 5.1 discrete channels of vibrant surround sound for broadcasting, home cinema, cinema, PC, online streaming, and video game programming.

An AC3 is a 5.1 file, but it is compressed. Dolby E is a 5.1 file, but it is compressed. They are compressed streams that need to be decoded (though, yes, they do decode into 5.1 channels). This answers part of the OP's first question. The 5.1 discrete is 6 separate files. This has been my understanding for a while. Your quote is largely Dolby Marketing speak to distinguish it from PLII and PLI. An encoded, compressed singular file, such as an AC3 is not what you deliver when the specs say "discrete 5.1".

Originally Posted by tom_lowe

As for LtRt, ProLogic 2 will unfold it to 5.1.

Sweetie, PL II is a 5-->2-->5 process that can use Bass Management to send signal to the sub. It is not 5.1. In other words, there is no LFE channel. This is also at Dolby's site.

I am asked to proved AC3's and Dolby E files frequently.

[lexaudio]

Originally Posted by minister

An AC3 is a 5.1 file. Dolby E is a 5.1 file. This answers part of the OP's first question. The discrete is 6 separate files. This has been my understanding for a while.

PL II is a 5-->2-->5 process that can use Bass Management to send signal to the sub. It is not 5.1. In other words, there is no LFE channel. This is also at Dolby's site.

I am asked to proved AC3's and Dolby E files frequently.

Alrighty here. There seems to be a major confusion of what "discreet" means.

Let's start from the top.
you have the 5.1 and the LTRT often referred to as the 6 track and 2 track.

Discreet means that there is a separate center channel mix, left channel mix, right channel mix ect.
It has nothing to do with files.

Now a client may ask for "6 discreet files for the 5.1" or "5.1 discreet tracks". That's because they don't know what discreet means.

Do you refer to a stereo mix as a discreet stereo mix? NO. You refer to it as a stereo mix. Just because there are 6 channels doesn't make it any different.

LTRT's, folddowns, 2 tracks whatever you want to call them are not discreet mixes.
They do not unfold into a complete, discreet, 6 track mix.

Let's take a look at a 5.1 interleaved file. How is it not discreet?
You look at the file, and see only ONE file. Just like a stereo interleave file.
Once you bring it into a DAW like PT which splits the files, and Nuendo which reads the interleave, the channels are still discreet.
You have in both systems a 5.1 discreet mix.

Meaning, a left channel mix, a center channel mix, a right channel mix, ect.

An AC3 is a discreet 5.1. Dolby E is a discreet 5.1. LTRT is not.

So, whether being asked to deliver a 5.1 as single mono files, interleave, AC3, DTS or Dolby E, they are ALL 6 track 5.1 discreet.

File delivery has nothing to do with the term "discreet".

[minister]

Originally Posted by lexaudio

I assume you mean fold downs.

You assume wrong.

The word is "discrete".

An interleaved file is discrete; it does not need to be decoded.

I stand by what I said about AC3's, DTS, and Dolby E. I have never heard any one call them discrete, but they are not matrixed.

[dr sound]

http://www.merriam-webster.com/dictionary/discrete

[lexaudio]

Originally Posted by minister

You assume wrong.

The word is "discrete".

An interleaved file is discrete; it does not need to be decoded.

I stand by what I said about AC3's, DTS, and Dolby E. I have never heard any one call them discrete, but they are not matrixed.

Well that's dyslexic of me. I suppose I should proof read before I post. DERP.

So let me understand you better.

An encoded file is not discrete because it has to be decoded.
And AC3 or DTS or Dolby E does not deliver a "true" or "complete" 5.1 mix from the dub stage because it has to be decoded.

Clarify your definition of what discrete means.

Just want to make sure I'm understanding you before I comment.

[mr.armadillo]

Originally Posted by lexaudio

An encoded file is not discrete because it has to be decoded.
And AC3 or DTS or Dolby E does not deliver a "true" or "complete" 5.1 mix from the dub stage because it has to be decoded.

Of course those formats deliver a complete 5.1 mix. However, this has nothing to do with this, rather stupid, discussion about the use of the word "discrete".
Jeez, guys, how complicated can it be?
If delivery asks for "6 channels discrete", they want one single dedicated .wav- or .aif-file for each channel, no decoding needed. An AC3- or DTS-file is not "discrete", but decodes into 6 discrete channels. Ok?

[lexaudio]

Originally Posted by mr.armadillo

Of course those formats deliver a complete 5.1 mix. However, this has nothing to do with this, rather stupid, discussion about the use of the word "discrete".
Jeez, guys, how complicated can it be?
If delivery asks for "6 channels discrete", they want one single dedicated .wav- or .aif-file for each channel, no decoding needed. An AC3- or DTS-file is not "discrete", but decodes into 6 discrete channels. Ok?

Wasn't asking you, was asking minister based on his comment.

It isn't complicated.

For delivery I have seen,
6 channel uncompressed mix
6 channel wave files
6 channel AIFF files
6 track discrete surround mix
5.1 mix
uncompressed surround mix
surround mix
6 track pro tools session
6 track DA88
5.1 mono wave files

Discrete has little to do with the "delivery" often have to clarify with the client because they don't know what it means either.
Technical engineer writes what they need, then it is re written or handed down and someone else tried to update it.

You can see from the list how different they are, and how confused they are.

the OP asked what the difference between 5.1 and 5.1 discrete was. There is no difference.

Minister stated that 5.1 audio files were discrete and AC3 DTS ect were not because it had to be decoded.
Discrete in either case refers to the channels played back. If I'm on the dub stage, A/B'ing the direct mix and the MO to do a fix, am I not hearing a discrete mix from the MO?
Is the MO not discrete? What about the specs that ask for a 5.1 discrete MO disk?

If I have a BluRay with a full range, uncompressed mix, DTS mix and DD mix, do I not hear a full 5.1 mix of the BluRay?

What the 5.1 goes to in terms of encoding has nothing to do with the term discrete. Is the end result of what you are delivering a 6 track mix?
Then its discrete.
I've never been asked to deliver an AC3 or Dolby E, so I can only imagine the spec on that.

The delivery specs are often completely different from one place to another.
The client doesn't know how to convey that they want a full range, non encoded (uncompressed) 5.1 (6 channel mix).
Or as one of my more recent clients asked "discrete surround tracks (6 channels of 5.1 audio)".

I think we all know delivering 5.1 audio files is discrete. We know that AC3 plays back discrete.

5.1 discrete means, playback of 6 channels of audio.