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Surround sound mix, file delivery and 5.1 export channel order

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Nikos Tsimpetonidis
Surround sound mix, file delivery and 5.1 export channel order
on Mar 13, 2011 at 9:49:53 am

Hello everyone

i would like your help on something. I'm currently doing a small movie with my students in school ( i'm a musicologist ) and decided to have the sound of the film in Surround sound format, 5.1 . i use my Saffire pro 40 as my soundcard. My questions are:

1) when i finish my surround mix and do all the surround panning etc. in either Logic, or Pro Tools, how do i encode it in one surround sound file? is it possible through either one of the two DAWs, Logic or Pro Tools? or i will have to use a software encoder like A.Pack, or Dolby Media Production suite ? if i have to go the second route, do i export a polly audio file or 6 discreet mono audio files?

2) if i export 6 descreet mono audio files, will i have any problem with my mix after they will be encoded as one 5.1 AC3 audio file? Meaning will i here the mix right as i did before i merge the six discreet files?

3) Considering that the final product ( the movie) will be burned on a DVD for inside school projection and maybe will be played in small student film festivals, what should my 5.1 export channel order be? L, C, R, Ls, Rs, LFE like film ( i know Pro Tools give this) or the ITU Standard, L, R, C, LFE, Ls, Rs or different?

I have done music for small films earlier, but it's my first time with surround sound so any advice would be most appreciated
The movie will be cut in Premiere Pro CS5 on my Mac Book Pro, if this info is needed . Thanks in advance for any help and advice and sorry for my bad English.

Best Regards,
Nikos Tsimpetonidis

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Jean-Christophe Boulay
Re: Surround sound mix, file delivery and 5.1 export channel order
on Mar 14, 2011 at 2:47:58 pm

Hi Nikos,

That sounds like a fun project that will also teach some good technical practices. There are many standards and practices in surround sound production and navigating those is half the work.

1. All the main DAWs can bounce a multichannel audio file of the finished result. The track order in that bounce usually follows what you have set for monitoring, with some notable exceptions (step forward, Pro Tools!). The standard practice is to always bounce surround material as discrete audio files. That is much simpler in the following operations and eliminates the mystery of the track order inside an interleaved file. An interleaved mix will not work on a system with different track assignment, while discrete files can be made to work in every situation. The same bounce can be used for DVD, HDCamSR, DCP, digital distribution... whatever delivery format.

2. Not at all, that is why we should bounce to discrete files. Most AC3-creation tools work by you importing the discrete audio files and assigning them to channels, so the discrete files are necessary at this stage.

3. To sidestep any possible problems here, the DVDs should be authored using AC3 files. That way, no matter what player or software reads it, the Center channel will come out of the plug labeled "center" on the back of the machine. I've seen cheap DVD players output discrete channels in cryptic ways and, believe me, unplugging and plugging stuff in the projection theatre minutes before the screening to find the correct assignments is no fun at all. AC3 eliminates that possibility. Any archived video file should use audio track assignment of L,R,C,LFE,Ls,Rs which almost everyone expects now.

Good luck on this project.

JC Boulay
Technical Director
Audio Z
Montreal, Canada

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Nikos Tsimpetonidis
Re: Surround sound mix, file delivery and 5.1 export channel order
on Mar 14, 2011 at 9:48:59 pm

Hi Jean- Christophe,

Thank you for your immediate reply. Yes you can say it is a fun project and my students and me of course are really enjoying it :) Thanks for your help and advice, it all comes clear to me now. So i'll use one of the two DAWs for the mix, and after that i'll export 6 discreet channels to encode them with a software encoder,in the turn you told me, L, R, C, LFE, Ls, Rs and on AC3 format.
I believe the whole surround sound idea will be difficult at start, but as people say every start in new things is difficult. In time and through experience it becomes simpler. For sure it will be very good practice for me and for my students also. Thanks again for your help, advice and time. It's been really useful . If there is anything i could help you with, let me know.
Wish you all the best in everything.

Best regards,
Nikos Tsimpetonidis

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Elliott Balsley
Re: Surround sound mix, file delivery and 5.1 export channel order
on Dec 14, 2011 at 10:31:20 am

I'm confused about channel order settings. You say to use L, R, C, LFE, Ls, Rs, and that's what I've heard also from the projectionist at my school. But here I have a problem:
I'm trying to burn a blu-ray to an .img file using the basic template in Compressor 3. I've exported my FCP timeline as a quicktime movie with 6 discrete audio channels for the 5.1 mix, using the standard order (L, R, C, LFE, Ls, Rs). But in Compressor's Dolby Digital settings, there is no option to match that order. The closest thing is "3/2 (L, C, R, Ls, Rs)" with a checkbox to enable low frequency effects. Does this mean I need to re-export from FCP with the non-standard channel order, just to make Compressor happy? This seems weird.

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