Dolby

[c3kings]

Dear All,
Is it correct that 5.1 sound mixing is only for film optical track and DVD? If my final output is HD or Digibeta, then 5.1 is not available.
Also, if I want to have 5.1 mix, then I must have Dolby license. Am I right? Can I ask the mixing studio to make a 5.1 mix without having a Dolby license? What is Dolby about? Does it mean a better 5.1 or something?
Last question: is there any stereo optical film sound track in the world or only mono optical and 5.1 optical film sound track?
Please forgive my ignorance, but I just want to make it clear.
Maybe, can anyone direct me an appropiate web site to get more knowledge about the issue?
Thank you very much.
King

[timapter]

King, some (not all) answers:

Yes, only dvd or optical.
No, you can mix 5.1 but not use Dolby. Dolby is a type of encoding, and others exist (DTS for example).
Im not sure about stereo optical tracks, but I dont see why not. If it can carry 5 tracks, it could theoretically carry two. And when you say mono optical, I think you might be mistaking it for the analogue/magnetic backup mono? Maybe someone can clarify on that, I could be wrong (dont work in positive print medium, so Im no expert)

Cheers

[Noiz2]

King,
Pretty much No almost none of what you have said is in fact the case. Dolby Digital 5.1 is a specific format that is not part of the optical track. It is only used in film (I may be wrong on this but I believe that the DVD stream which is AC3 encoded is not the same as the DD stream which I believe is an MP3 encoding - But I may be wrong and they may both be AC3) **( they are the same format AC3 but DD for film is still not an option with out a license because of how it gets put on the film)** . It is proprietary and you do need a license and it will cost a bundle. Even if you could put it on your Digi Beta you wouldn't want to because it wouldn't get decoded when you played it back. You can get a discrete 5.1 (6 tracks) mix from any stage that is mixing 5.1, but that isn't going to do you much good for screening because your deck only has 4 tracks.

35mm Optical tracks come in mono & stereo. However most "stereo" tracks are actually "matrixed" so that they encode a 4.1 mix on two tracks. This is what is known as Dolby Stereo or Dolby Surround. It is basically the same as Prologic.
The pattents on the Matrix have expired and there are a number of competitors. SRS is one of the best but there are a number. License fee's vary from $0 to ??. Dolby (last I checked) wanted $1,200 for a festival only Surround license and $12,000 for a full Dolby Digital license. The last film I did with SRS all the asked for was a signed agreement and there logo tagged onto the head credits (Dolby requires this also).

But there's MORE! For festivals and Video there is also Dolby E. It's sort of Dolby Digital for video tape, and it doesn't require a fee (but you probably have to buy a box).

Also SRS can encode 7.1 but you wont get 7.1 out unless you use their decoder.

Then you have SDDS, and DTS and ?????

There are a lot of formats out there. The most universal for 35mm are
Mono
Stereo
LtRt (matrixed 4.1 in some Dolby Surround compatible format) ***
Dolby Digital (you still need to have a matrixed mix as backup) **
SDDS **

Video is probably
Mono
Stereo
Prologic or SRS (they are compatable) *
Dolby Digital (if your on a DVD) *
DTS (also I think a DVD only format) * -(nope I was wrong on that just not a common film format)
Dolby E

*** = you need a license but as long as you don't claim the format you are in the clear - but you may not be able to get the material encoded with out the license (Dolby gets nasty with studios mixing with out license in hand. But if you can get it encoded playback should not be a problem.

** = Absolutely need a license uses proprietary hardware and format encoding you have to get them to do it.

*= not a problem finding encoders. Technically you need a license for some applications, but not others. But primarily the license is for the use of the Logo not the encoded file. Also most of these formats will be automatically detected by playback boxes so it's sort of plug and play. If you want to have the Logo on your film, then you HAVE to have a license agreement. But I don't think they are very pricey.

And Lastly you need a sound supervisor or at least a Post supervisor that is familiar with what is in use. You can really screw yourself if you get hot on a format (like 5.1) and get you mix in it and then find out that hardly anybody can play it back. The audio delivery formats for video are about as stable as hot jello right now. I almost always recommend against 5.1 unless you are mixing on a real mix stage and are going to film. It's the new buzz word but it's 99.9% BS. Almost nobody hears a 5.1 mix properly in a home setup and very few films spend much time on the last 2.1 of the mix. L C R is the mix (and you can do that in stereo with the phantom center) and then as an after though toss a little in the surrounds and maybe a little in the boom track. Epics of all types get a more rounded mix but still probably 70+ % of the theatres in this country don't play the Dolby Digital even if the film has a DD track and way too many don't decode the LtRt, AND there are still plenty that will play your movie in mono.

SO if you have the budget and your going to a 35mm print in major markets go for it. If your going to DVD and you have a subject that really can use the 5.1 AND you are selling to a market that is likely to have 5.1 setups at home MAYBE go for it. Otherwise streight stereo is my first choice and Matrixed is second for 35mm and stereo or poss prologic for video.

FYI Matrixed for theatre is different than video in one crucial area. Optical tracks NEED to have SR (or A) noise reduction on them and video does not. And of course levels are different.

Long winded but I hope it helps
SK

[timapter]

Thats the expert I mentioned.

[ptalsky]

Hey Scott,

One thing to add to your post - With Sony Vegas + DVD, it comes with the AC3 encoder (decoder?) and a license so you can burn AC3 encoded DVDs and they will play "full" Dolby (I think it's 5.1, but not sure). I haven't tried any of this yet, but am thinking about taking an existing project I did in Vegas and testing it. Have you used Vegas?

And, while we're on the subject, anyone know what the difference is between Dolby and THX? And, how you encode for THX?

Thanks!

Phil

[c3kings]

Thank you for all of you, particularly, SK's long explanation.
I talked to the guy from studio. He told me that Dolby stereo mix would be Dolby SR, and it was still kind of surround sound, but the sound from the back was mono instead of stereo. Any thoughts?
Thanks.
King

[wabbit]

http://www.mtsu.edu/~smpte/timeline.html

This one breaks down the surround technology in a easily understood chart: http://www.mtsu.edu/~smpte/table.html

Hope that helps

[Noiz2]

Thank you for all of you, particularly, SK's long explanation.
I talked to the guy from studio. He told me that Dolby stereo mix would be Dolby SR, and it was still kind of surround sound, but the sound from the back was mono instead of stereo. Any thoughts?
Thanks.
King

SR is noise reduction. You would use that on an optical track for 35mm. I would check to make sure you want it on video, I doubt it especially with digi beta (isn't the audio track digital?). There is NO reason to use Noise Reduction on a digital track, UNLESS the places you are going to play it back from are going to decode it.

I did a feature that was shot on DV (the first feature on DV I was told...) and we got a full on mix on a stage, Dolby surround matrixed mix (actually SRS but same principal). We assumed that all the festivals would play back the film (video) through the Dolby Cinema Processors because that is what they were set up for then. So we did two printmasters One with the what would be used for the 35mm print (if the film ever got picked up) Dolby (SRS) surround Dolby SR encoded. And a Surround with out the SR for the DVD (ProLogic doesn't want the SR encoding). For about six months we were right and the SR encoded mix was great. But then everyone and there mother were submitting DV films to festivals and none of them had gone to the trouble and expense to do a "theatrical" mix and none were either matrixed or SR encoded. So we had to switch the prints we sent out. Matrixed tracks will sound fine over stereo but SR will sound TERRIBLE if not properly decoded.

SO check with the folks that will be playing your tape and find out if they will be playing your sound track through the cinema processor or not. AND definitely get you mix both ways (SR encoded and not SR encoded). If you cant get a definitive answer from your venues put the Encoded tracks on 3&4 and the non encoded tracks on 1&2 (I think non encoded will be a lot more common). You should also have them give you Stems if possible but at least get the 4.1 tracks as discrete tracks on a disk. It will make it MUCH easier to go back into the mix if you find you need to fix something down the line, and it's very simple for them to do.

One more word SOUND SUPERVISOR, well two I guess. A mix stage is a very expensive place to learn things.

[Noiz2]

http://www.mtsu.edu/~smpte/timeline.html

This one breaks down the surround technology in a easily understood chart: http://www.mtsu.edu/~smpte/table.html

Hope that helps

Great link. I went through the history of film sound links and learned a few things... I'll have to make some corrections to my post :~(

[wabbit]

The internet is an amazing thing. I can't remember what I did before it. Dark times those were.

Cheers