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Ryan Krickow
ISO Audio Tracks
on Feb 11, 2009 at 1:34:44 am

These are very basic questions but I just want to clarify. I see the word ISO used in reference to many different things... it can refer to "isolated" video and audio tracks, a disk image, exposure settings, and an international organization for standardization. When requesting that a production sound mixer provide me with a mixdown for picture editing and individual audio files to hand over to post sound would I ask for... a production sound mix and ISO tracks? Next, a production sound mix is usually mono, one track, with a left and right channel, correct? That being said, what is the difference between an audio track and an audio channel? Thanks, Ryan


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JC Boulay
Re: ISO Audio Tracks
on Feb 11, 2009 at 4:42:23 pm

ISO is the International Standards Organization. You could use the acronym ISO to describe any number of processes in any given industry, as the letters alone mean nothing without the number of the standard they relate to. For example, ISO disc images are files based on the ISO 9660 filesystem. Exposure values also relate to an ISO standard. Heck, the window frame manufacturer close to my home is ISO 9002-certified.

The three letters themselves mean pretty much nothing, which is why it's a very good idea not to use "iso" as an abbreviation for "isolated". Someone somewhere is going to be really confused. When requesting sound elements separated from the rest of the mix, ask for "split tracks" or "mixouts". Pretty much every sound person should understand that.

As for channels and tracks, on most gear and in most software a "track" is an audio stream which can have one or more channels. Channels are independant components of the track, usually allocated to speakers. So a stereo track will contain two channels, a 5.1 track will contain 6 channels, etc... Hence, one mono track can not contain two channels, left and right. That would necessarily be a stereo track. Most production sound I've worked with comes on two channels, but they are not left and right. They're usually Lav and Boom, the separate mics. Some production sound also comes in with a stereo mix on two channels, but we rarely use that in post. That would be your "production sound mix", but your audio post guy will need "production split tracks" to work. Don't take this differentiation of tracks and channels for granted, though. In many instances, the terms are used as if they meant the same thing.

IHTH

JC Boulay
Audio Z
Montreal, Canada
http://www.audioz.com


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Rob Neidig
Re: ISO Audio Tracks
on Feb 11, 2009 at 7:15:57 pm

As to channels vs tracks:


I typically think of channels as relating to a mixer and tracks to a recorder. Thus, for example, a Sound Devices 302 has three channels, that is 3 inputs, for different things. The output is then sent out as typically a stereo output, that is a left and right track. Within the mixer you determine on which tracks the channels will be recorded. Carry this view on and you get for example 48-channel mixers, with 48 different sources all being mixed down to two audio tracks (stereo).

Then there are recorders that have more than 2 tracks. Sometimes you may send each channel to its own track, sometimes you will mix several sources to one track.

As to the "iso" issue, yes "ISO" can mean a number of things, but I often hear video/audio people talking about recording mics to "iso" tracks. This would mean that if you have 2 people in a scene you would pan one mic all the way Left so it only gets recorded on track number 1, and pan the other mic all the way Right so it only gets recorded on track number 2. As JC says, this is more often called split tracks, but I have heard the term iso used. Where you start having to make decisions about how to split is when you have more than 2 sources, but are recording to stereo.

Hope this helps. Have fun!

Rob


Rob Neidig
R&R Media Productions
Eugene, Oregon


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Ty Ford
Re: ISO Audio Tracks
on Feb 11, 2009 at 11:18:29 pm

You nailed it JC, but I have minor additions.

"As for channels and tracks, on most gear and in most software a "track" is an audio stream which can have one or more channels. Channels are independant components of the track, usually allocated to speakers. So a stereo track will contain two channels, a 5.1 track will contain 6 channels, etc... Hence, one mono track can not contain two channels, left and right. That would necessarily be a stereo track. Most production sound I've worked with comes on two channels, but they are not left and right. They're usually Lav and Boom, the separate mics. Some production sound also comes in with a stereo mix on two channels, but we rarely use that in post. That would be your "production sound mix", but your audio post guy will need "production split tracks" to work. Don't take this differentiation of tracks and channels for granted, though. In many instances, the terms are used as if they meant the same thing."

A channel is usually something on a piece of audio hardware, a console, for example. It's not uncommon to refer to the left and right channels or left and right tracks of a video camera.

An audio track down here usually refers to one channel or track of audio. A track was historically a track on a tape recorder, but now is a track on a piece of software running on a computer.

There's also the possibility of a dual mono mix where all mics go to both channels. This is sometimes done to prevent postproduction people from just choosing one track for the audio.

Some sound mixers also feed dual mono but run the level of one channel on the camera down a few dB to allow for accidental overs. It's a safety net in case things get too loud. The, hopefully, the reduced channel isn't clipped.

Regards,

Ty Ford

Confusing? A little.




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Ryan Krickow
Re: ISO Audio Tracks
on Feb 12, 2009 at 8:39:52 pm

Thanks for all the info! That was definitely more complex than I had thought. So, if I wanted to get a mixed mono track (audio file) for picture editing would that come in 2 tracks (left and right speakers) and what terminology would I use to ask for it? Then, would I also ask for split tracks (instead of iso's) if I wanted to get 1 separate file per channel/mic for post sound? Would these audio files also be 2 tracks (left and right speakers)?

As an overview I'm looking for the correct terminology to use when asking production sound for audio files for the picture editor and audio files for post sound.

Thanks again, Ryan



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Ty Ford
Re: ISO Audio Tracks
on Feb 12, 2009 at 10:06:04 pm

>>[Ryan Krickow] "So, if I wanted to get a mixed mono track (audio file) for picture editing would that come in 2 tracks (left and right speakers) and what terminology would I use to ask for it?

Ryan, if you were feeding one camera with two audio tracks, you would ask the audio person for a mono mix to both tracks.

>>Then, would I also ask for split tracks (instead of iso's) if I wanted to get 1 separate file per channel/mic for post sound? Would these audio files also be 2 tracks (left and right speakers)?

Ryan, if you only have two mics you can split track them one to each channel/track. Most of the time that's what's done whether you have boom and lav on one person or two lavs each on a different person, or a boom on one person and a lav on another person.

If you have three or more mics and only two channels of audio on the camera and you want maximum flexibility in post, then you have to decide what's most important and put that mic on its own channel/track. This gets very tricky if you are a one person audio department. You can't really swing a boom ride its level and ride two other lav levels at the same time. Well you CAN, but eventually, you'll screw up, especially if the speaking is extemporaneous.

If you can't go back and redo because of a bad sound move, or if someone inadvertently speaks before you expect them to and you don't have their pot up, then you get what you get.

Paying attention to riding gain on three or more mics has required pretty much all of my attention, leaving me without the ability to swing a boom.

Hope this helps,

Regards,

Ty Ford



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Ryan Krickow
Re: ISO Audio Tracks
on Feb 12, 2009 at 11:15:22 pm

We're shooting dual system sound (with a production sound mixer and a boom operator) so we won't have the audio going to the camera. The main thing I'm trying to figure out in terms of tracks/channels & mono/stereo is the correct terminology to use when asking for the mixed audio (for picture editing) and separate audio files for each channel/mic (for post sound). Based on what has been said I believe that I would ask for a mixed mono track and split tracks. Is that correct? Thanks, Ryan



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Ty Ford
Re: ISO Audio Tracks
on Feb 12, 2009 at 11:24:54 pm

[Ryan Krickow] "We're shooting dual system sound (with a production sound mixer and a boom operator) so we won't have the audio going to the camera. The main thing I'm trying to figure out in terms of tracks/channels & mono/stereo is the correct terminology to use when asking for the mixed audio (for picture editing) and separate audio files for each channel/mic (for post sound). Based on what has been said I believe that I would ask for a mixed mono track and split tracks. Is that correct? Thanks, Ryan"

Ryan,

Dual system still usually runs audio to the camera for safety and possible sync up later. That's why it's called DUAL. This is new information you didn't mention before. How many tracks does the recprder have?

You can have mixed mono (one or two tracks) or mixed stereo in two tracks. Unless you have enough tracks, you can't have both mixed and iso. If you only have two tracks, you can mix mono to one and have one iso track for one source ONLY.

I advise you to stand aside and let the location audio folks talk to the post folks rather than trying to interpret something you are unfamiliar with. Listen to what they say. Ask questions. Learn.

Regards,

Ty Ford

Ty Ford

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Ryan Krickow
Re: ISO Audio Tracks
on Feb 13, 2009 at 4:52:06 am

I'm editing the project so I'd like to have a handle on the general procedures of getting audio during production and passing it along to post sound. We're in early pre-production and haven't hired the sound mixer but I'm almost positive it is going to be recorded on a 788T or similar audio recorder and there's a good chance the audio won't be recorded on the camera in which case I was mistaken in mentioning dual system sound. Here are the two main pieces of information I'm trying to get a firm handle on...

1. The correct audio file(s) for picture editing would be a mono mix track. What I'm not quite sure of is if there would be an advantage to having 2 mono mix tracks vs. 1 mono mix track? It seems like 1 mono mix track is all you would need for picture editing but I could be wrong.

2. The correct audio files for post sound would be isolated "iso" tracks or production split tracks.

Thus I would request a mono mix track(s?) and iso tracks. If audio gets recorded on the camera then all need is the iso tracks. Thanks for all your help! Ryan



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Ty Ford
Re: ISO Audio Tracks
on Feb 13, 2009 at 5:10:33 am

[Ryan Krickow] "1. The correct audio file(s) for picture editing would be a mono mix track.

>>Yes, if he does a mono mix track

What I'm not quite sure of is if there would be an advantage to having 2 mono mix tracks vs. 1 mono mix track? It seems like 1 mono mix track is all you would need for picture editing but I could be wrong.

>>As I mentioned before. With two tracks of mono, some folks like to run one track a few dB lower than the other in case of unexpected outbursts. the main track might clip, built the lower one (hopefully) won't. Don't know if the mixer used will allow that.

2. The correct audio files for post sound would be isolated "iso" tracks or production split tracks.
If you want to have each mic on a separate track, yes. I think "Split Tracks" usually refers to the sending of different audio to each of two tracks. Whereas "Splits" frequently refers to dialog, music or effects tracks. Dialog splits, Music splits, and EFX splits. The word "stems" is also used the same way.

Thus I would request a mono mix track(s?) and iso tracks.
>>For what?

If audio gets recorded on the camera then all need is the iso tracks.
>>Yes, but having a single mono mix on a camera track would be prudent.

Ty Ford





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Ryan Krickow
Re: ISO Audio Tracks
on Feb 13, 2009 at 5:39:55 am

I would request a mono mixed track and iso tracks from production sound for picture editing (mono mixed track) and delivery to post sound (iso tracks). You said "Yes, if he does a mono mix track", in what case would a production sound mixer not be able to provide this? Thanks, Ryan



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Ty Ford
Re: ISO Audio Tracks
on Feb 13, 2009 at 5:41:45 am

what's more important is whether your sound guy can provide that.

Ty Ford

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Greg Curda
Re: ISO Audio Tracks
on Feb 17, 2009 at 11:23:44 am

Hi Ryan,

Is all this clear??? It's important that you understand.

If you are shooting on a digital camera then a production mix track could be sent to the camera. If it were me, I would use Ty's method of one channel being lower to cover any unforseen peaks. For you, these "mix" tracks will come in with the ingestion process of the camera tapes. Use only one track and mute the other. This is your production "work" track, or "guide" track.

If the sound mixer will use a 788, then the individual mics will be "iso ed" on their own individual tracks to be used later by the dialogue guys. I can't imagine more than six tracks being used for this unless this is a new Altman picture!! In that case, the mixer should have 2 tracks left to put the "mix" or "guide" track, for safety, in case anything happens to camera.

Your job is to tell the story with picture and dialogue. The production mixer's job is to capture the best dialogue possible, and give you something good to work with. This is, at the same time, easier and harder with the advent of multi-tracking. In the old days, the mono mix was all there was. Now, we have choices, but too often, this has led to a softening of technique and craft.

Ah, there I go again..haha.. If all else fails, take the primary boom track and use that. You can always request alternate tracks (lavs, plants, etc.) if you have a problem...

G








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Ryan Krickow
Re: ISO Audio Tracks
on Feb 18, 2009 at 4:32:52 am

Hi Greg,

I feel at this point I should backtrack a bit and provide some additional information since the subject matter (iso tracks) involves more than just the audio recorder and production sound mixer...

1. We are shooting on the Red One camera and I'm trying to decide between requesting Data DVDs from production sound or if I should ask the Red Tech to backup the audio files onto the two on-set hard drives that are being used for the R3D storage/backup. Since everything is going to end up on the editing drive anyway this would help streamline the process (and also allow on-set syncing of sound for playback-if audio and picture are recorded separately).

2. In regards to dual-system sound, I'm not sure how common it is to connect a wireless receiver to the Red One camera in order to record a mono mixed track with the picture? There are a lot of steadicam shots so having the audio recorder directly connected to the camera isn't always going to be an option. (I've posted this question on the Red Network.)

3. If this dual-system method is NOT standard practice I imagine the other option is to record the mono mixed track and iso tracks on the audio recorder and sync everything in post using the timecode/slate.

That's the situation I'm working with. If you have any recommendations I'd really appreciate it.

Thanks, Ryan


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Ty Ford
Re: ISO Audio Tracks
on Feb 18, 2009 at 4:50:21 am

1. We are shooting on the Red One camera and I'm trying to decide between requesting Data DVDs from production sound or if I should ask the Red Tech to backup the audio files onto the two on-set hard drives that are being used for the R3D storage/backup. Since everything is going to end up on the editing drive anyway this would help streamline the process (and also allow on-set syncing of sound for playback-if audio and picture are recorded separately).

2. In regards to dual-system sound, I'm not sure how common it is to connect a wireless receiver to the Red One camera in order to record a mono mixed track with the picture? There are a lot of steadicam shots so having the audio recorder directly connected to the camera isn't always going to be an option. (I've posted this question on the Red Network.)

3. If this dual-system method is NOT standard practice I imagine the other option is to record the mono mixed track and iso tracks on the audio recorder and sync everything in post using the timecode/slate.

Ryan,

Anything else you're not telling us?

Why would your audio recorder be connected to the camera?

3. yes, that's correct.

Ty Ford

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Ryan Krickow
Re: ISO Audio Tracks
on Feb 18, 2009 at 8:37:06 pm

I apologize for my lack of detail in the beginning, I just never expected this thread to go so far beyond iso track terminology. To answer your question, the audio recorder would have to feed the Red One camera a mixed track if you wanted to have the picture and sound recorded together on the R3D files. I imagine this would be done either using a wireless receiver or a direct connection to the camera. Thanks, Ryan



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Ty Ford
Re: ISO Audio Tracks
on Feb 18, 2009 at 8:49:07 pm

Ryan,

Why would you feed a recorder to a camera. That's what a mixer is for.

Ty Ford



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Greg Curda
Re: ISO Audio Tracks
on Feb 19, 2009 at 10:16:45 am

Hi Ryan,

What Ty and the rest of us are trying to get to is that the recorder normally doesnt send anything anywhere. You have far bigger problems with the paperwork than worrying about the guide track.

Here's a suggested workflow: Multi-track using a 788T or similar recorder. Back-up files daily to 2 drives (one goes to you). Ask the mixer to record a mono mix track on, say CH8 of the recorder, and also feed that track to the camera for a guide (let him figure out whether to wire or RF). Done. You cut from camera tracks and conform later.

Unless something has changed in the last month, your bigger problem stems from the fact that the RED uses proprietary file names. As far as I know, you cannot log scene and take. I just finished a show last month using RED. We decided to duplicate the RED file names on Sound (just so there was no possibility of mismatch) and keep a 3-way log (camera, sound, script) of the file names and corresponding scene/take numbers. This must be iron clad, or you will never find your tracks. The RED simply increments the takes within a given "roll" number. You, as the editor,can always rename all the files to a more conventional format, but don't forget to change all the sound too!!

Also be aware that the RED loses TC jam at every battery change, so sound needs a fast jamming scenario...

Are we havin' fun yet??

G





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Ty Ford
Re: ISO Audio Tracks
on Feb 19, 2009 at 2:19:36 pm

Nice one, Greg.

Regards,

Ty

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Ryan Krickow
Re: ISO Audio Tracks
on Feb 20, 2009 at 10:46:11 pm

I really appreciate your help Greg! Your workflow info helps, I'll definitely request that the mono mixed track be fed to the camera if possible. In terms of labeling I was thinking of having the audio labeled by scene, take, and track and then in FCP I would rename the video. The Red Tech is going to keep a log of the R3D filenames, scenes/takes, etc that I can use as a resource. Then, if the mono mixed track was recorded on the camera I would start cutting otherwise I would start by merging the mono mixed track with the video. Once I got final cut I would go back through and drop all the additional audio tracks into the timeline before creating an OMF for post sound. I think I've got a pretty clear idea of how this works now.

Here's the next step that I'm trying to figure out. With the video and audio merged, each containing the scene and take information, I could create an OMF and hand it off to post sound with a hard drive containing all the iso tracks or I can drop all the iso tracks into the timeline before creating the OMF in order to save post sound time. What I'm not sure about is the BWF workflow in FCP. There are programs such as BWF2XML but I was told the OMF will lose the metadata and Protools doesn't accept Quicktime movie audio files. Any advice from you guys would really be appreciated. Thanks, Ryan



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Greg Curda
Re: ISO Audio Tracks
on Feb 21, 2009 at 12:29:24 pm

Hi Ryan,

I think it's prudent to have your sound report list the corresponding camera file names as well. All due respect to your RED tech, but even with three cross logs, there were some takes that were still mis-matched. In the heat of production, don't you know...

As far as I know our editors use BWF2XML and the OMF from FCP DOES NOT carry sound metadata to ProTools. So I don't think source TC drag and drop will work. And ProTools absolutely DOES accept Quicktime picture and track.

Let me double check my facts and get back to you... Can anybody else confirm or deny my allegations?

G



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Ty Ford
Re: ISO Audio Tracks
on Feb 21, 2009 at 1:46:35 pm

Greg,

Great post. Keep 'em coming.

Ty

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Ryan Krickow
Re: ISO Audio Tracks
on Feb 22, 2009 at 2:07:22 am

Good call on the record keeping. My understanding is that when you convert BWAVs to Quicktime movie files using BWF2XML the timecode is maintained though you lose the rest of the metadata when exporting an OMF. I could be wrong but that's what I've read. Also, in terms of dropping the iso clips in before exporting the OMF... since the Quicktime movie files maintain their original timecode (and this is before the OMF is even created) this shouldn't be a problem. I too would appreciate someone piping in if they have a lot of experience with the BWF2XML program.

Below I've provided my general notes regarding camera and production sound... I don't mention jam syncing the camera timecode to the audio recorder's timecode since I'm not sure whether audio will be running 29.97 ndf timecode or 23.98 (depends on their equipment). My understanding is that sound is in charge of timecode so depending on which timecode is used I assume they will follow the proper procedures to keep sync. I really appreciate your assistance Greg. Thanks, Ryan

CAMERA
• Shooting on the Red One Camera.
• Frame size is 4K 2:1 (Finishing 2.35:1)
• Camera Firmware Build 18
• Redcode 36
• Shooting at 23.98 fps
• Select Time of Day (TOD) timecode as the primary timecode track.
• Make sure the Incremental Reel option is checked and properly configured so that each reel has a unique name. Start with reel number 001.
• Media will be backed up on set using 2x Caldigit VR 2TB External Hard Drive Arrays. At the end of each shooting day one drive will be delivered to the editor, the media will be copied, and the drive will be returned.

PRODUCTION SOUND
• Record 24bit 48kHz Broadcast Wave Files (BWF)
• Record a mono mixed track and iso tracks. (Feed the mono mixed track to the camera if possible.)
• Scene, take, and track numbers are to be embedded into the filename (Example: 27A-2-T2.BWF)
• Use 29.97 non-drop frame TOD timecode. (Use 23.98 if possible.)
• Include R3D filenames in the sound log and keep the sound roll number consistent with camera reel number.
• Media will be backed up on set using 2x Caldigit VR 2TB External Hard Drive Arrays. At the end of each shooting day one drive will be delivered to the editor, the media will be copied, and the drive will be returned.



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Ty Ford
Re: ISO Audio Tracks
on Feb 22, 2009 at 3:23:38 am

[Ryan Krickow] "My understanding is that sound is in charge of timecode so depending on which timecode is used I assume they will follow the proper procedures to keep sync."

There is no rule for who is in charge of timecode. If any department is, it's post editing.

Regards,

Ty Ford

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Greg Curda
Re: ISO Audio Tracks
on Feb 22, 2009 at 9:49:18 am

Flow looks good... Just have production mixer pour through CC forums on RED, and also check RED site audio forum for any late-breaking news, and just general procedural history...

Best of luck with the show...

G



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Ryan Krickow
Re: ISO Audio Tracks
on Feb 25, 2009 at 8:24:33 am

I really appreciate all the help you guys have given me! Thanks, Ryan



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