Jean-christophe Boulay
Forum Replies Created
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Surround mixing is a pretty involved subject. I’d recommend you tread very lightly. There is still debate amongst pro audio engineers as to the best practices and there are many standards to understand and apply, especially levels-wise, to ensure a mix that is reproduced correctly. And that is based on the assumption you’re mixing in a properly-calibrated 5.1 room with adequate metering. If you do not grasp these concepts or have access to the proper environment or tools, I’d recommend you either hire an experienced mixer or just let it be. Otherwise, you could be tilting at windmills for quite a while.
A good stereo mix is miles better than a bad surround mix.
JC Boulay
Technical Director
Audio Z
Montreal, Canada
http://www.audioz.com -
Most documentaries I’ve been involved with have been mixed in stereo. In fact, whenever I’ve seen docs in surround, I’ve never found it to be pleasing. A documentary rarely has the intention of putting you in the action, which is the whole point of surround sound. Documentaries are usually more like looking at something through a window than being in the middle of it. I find that, aesthetically, good ol’ stereo sound supports this much better.
Anyways, since HDCam only has four audio channels, you couldn’t fit the discrete 5.1, and LtRt is not worthy of the investment in the surround mix. It’s kind of like paying for insane CGI and exporting it as an MPEG-1.
I’d still recommend getting the audio mixed by a pro if at all possible. Stereo sound is actually harder to get just right than surround. You can premix, but having someone go over it with experienced ears and knowledge of standard practices will maximize the impact in festivals. Even on a tight budget, there is a lot that can be improved in a tight timeframe, most of the time.
Try talking to audio postprod facility higher-ups. You’d be surprised how ready some are to support new directors.
IHTH,
JC Boulay
Technical Director
Audio Z
Montreal, Canada
http://www.audioz.com -
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
http://www.audioz.com -
If you’re talking post-production DAW, it’s Pro Tools, hands down. There’s a good following for Nuendo, but all sessions, stems and elements shared between facilities are mostly PT-based. With PT9 opening up formerly TDM-only features to native systems, I think PT penetration in the lower-budget productions will continue. Logic is hard to beat for composing music to picture, but post-prod is clearly not a priority in its development. Anyways, you said “PC”, so let’s forget Logic.
So it’s Pro Tools. Or Nuendo, if you’re feeling rebellious. Or Pyramix, if you’re French.
IHTH
JC Boulay
Technical Director
Audio Z
Montreal, Canada
http://www.audioz.com -
FCP is probably simply outputting through another device or output. Go to your Audio/Video Settings (opt+cmd+Q) and set your Audio Playback to whatever device you are monitoring through.
IHTH
JC Boulay
Technical Director
Audio Z
Montreal, Canada
http://www.audioz.com -
Ah-ha! I was about to post that most mixers I know go right to Vari-Fi for that effect. If you have PT and that, problem solved.
JC Boulay
Technical Director
Audio Z
Montreal, Canada
http://www.audioz.com -
Hi David,
To be sure I understand correctly, you have received the full mix, which doesn’t clip itself, but contains a some dialog that is clipped? If so, there really isn’t much you can do. If you have the actual dialog audio file that clips, there’s iZotope RX which can usually save it quite well with its Declip function (https://www.izotope.com/products/audio/rx/).
Once the clipped audio is mixed with other audio, you lose the opportunity to fix it, since the clipping is no longer at the levels where RX will work to fix it. The process will mash the whole mix up before it does anything to the clipping. In that case, you could ask your audio guys to have a look at what they can do on their side. It’s their mistake, after all. And a biggie.
IHTH,
JC Boulay
Technical Director
Audio Z
Montreal, Canada
http://www.audioz.com -
As regards video formats in PT, you are limited only by the video interface on the PT machine. The setup that is probably most used these days for sound post is a BMD Intensity Pro in the PT machine and a Prores file on the timeline. You can go up to 1920×1080 without problems this way. The video file should probably be kept on a separate hard drive from you audio session, unless your track counts are pretty low. If the video will not be output from PT and will be monitored only on the computer monitors, you can go for pretty much any QT video format you may want.
IHTH,
JC Boulay
Technical Director
Audio Z
Montreal, Canada
http://www.audioz.com -
The DMU CPU is the Dolby Mastering Unit (or something to that effect). It’s the box we use to encode mixes for the analog print masters to go out to theatres. I don’t think Dolby promote it at all, since it can’t be bought from them.
When you enter a partnership agreement with Dolby, you buy the remote and meter bridge for it and can request a unit whenever you have a master to do. We happen to be lucky here as we have one of the regional units almost permanently in the rack. It’s a big 4U box half-full of emptiness, really, once you open it up. You basically have I/O for 10 channels of AES/EBU plus timecode, the encoder CPU itself, an MO-Drive for the masters and connections for lots of different remotes and meters you could have attached. This is the sole bit of equipment I can think of that uses MO-Disks as its medium. Encoding is a real-time operations, akin to any recording locked to timecode and is done simultaneously in Dolby Digital, EX or not (SRD format), and LtRt (SVA format). We send the MO Disk to whatever facility is doing the print masters. Once every few months, a Dolby rep will stop by and take the logs on the DMU, to be sure you paid all your encoding royalties. There’s no getting around them.
We tend to use the DMU a bit less since more projects go out as DCP only, but many still go out dual-format.
The info about Dolby requirements is hard to find without contacting a rep, but I found this on GS:
https://www.gearslutz.com/board/post-production-forum/199189-dolby-facility-approval-requirements.htmlIHTH,
JC Boulay
Technical Director
Audio Z
Montreal, Canada
http://www.audioz.com -
Hi Peter,
For material intended for DVD, I’d go for a dialnorm of -27, mainly because it’s what most broadcasters we go to air on ask for, so the workflow can stay the same. I’m kind of lazy that way. I think it’s what most people are using on commercial DVD’s, too. Others I know work to -24, as that’s another pretty common spec. I’ve never really investigated the sonic difference between the two, I basically read the specs and stick to them. I almost never work on material intended solely for DVD and am usually working to broadcaster specs.
For the creation of the LtRt, I normally use the DMU. I just have to open up a stereo track in PT and can record it in real-time while proofing the final mix. I use Neyrinck for Dolby-E and love it, so SoundCode would surely be my first port of call for a software LtRt solution as well. For straight downmixing duties, I use Waves M360.
JC Boulay
Technical Director
Audio Z
Montreal, Canada
http://www.audioz.com