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Audio; AMA-link or Import

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Ben Harris
Audio; AMA-link or Import
on Mar 30, 2018 at 11:25:06 am
Last Edited By Ben Harris on Mar 30, 2018 at 11:27:17 am

Hi,

I'm working on a feature length documentary as an AE and it's been a long time since I've used Avid properly, and the first time for a project of this scale.

I was wondering what the preferred workflow is for high quality on set audio on projects such as this. Is it better to AMA-link the WAVs so we do not need to relink before exporting for a mix in Pro Tools or do people generally import to MXF and then relink? I was just wondering if there are any performance issues with the AMA-link version (24 bit / 48khz WAV) that are generally known or should this be fine?

If it is generally better to do the import to MXF then what is the general workflow for this?

Thanks,

Ben


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Shane Ross
Re: Audio; AMA-link or Import
on Mar 30, 2018 at 6:00:01 pm

Well, how will be mix be done? Not sure that's even relevant question though. I import. And most of the time I export an AAF to the audio mix and they use that audio as final. Audio conversion is pretty much lossless, as audio doesn't take up much space. BUT, some places like to CONFORM with the masters, so you give them ALL of the masters, and an AAF, so they link to the masters. But that shouldn't change how you import audio. I simply import. I only AMA video

Shane
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Read my blog, Little Frog in High Def


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Brent Marginet
Re: Audio; AMA-link or Import
on Mar 30, 2018 at 7:59:38 pm

I never AMA Link anything if I can but especially Audio. AMA is the worst way that I've ever worked with for Linking to Media. I find that it becomes unlinked far to often and there are times when crucial Metadata does not show up in Avid. Yet I prefer Avid over all other NLE's.

I use folder Management and if the Audio has to go out of house then Export an AAF with Embedded Audio like Shane suggested. If the project stays in house then I Export and AAF that Links to the Audio and PT will automatically link to the OP-Atom Audio in the Avid MediaFiles Folder. I also have the luxury of working with a guy who is real handy with scripting and programming so he wrote a script that copies only the OP-Atom Audio files to the HD that must go to the Audio Facility. That one is really nice because it stops the whining about how much DATA they have to COPY.

"MY MEDIA/PROJECT MOTTO: If you think three copies of your Media or Projects are enough. Take a moment to place a value on them and then maybe add two more. Hard Drives are now stupidly cheap. A RE-SHOOT AND YOUR TIME AREN'T."


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Ben Harris
Re: Audio; AMA-link or Import
on Apr 2, 2018 at 1:08:21 pm

Thanks for this information. Very useful. So most engineers are happy to mix with the MXFs? That was my main concern. I guess we'll do this and provide them with the originals if they are required.


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Brent Marginet
Re: Audio; AMA-link or Import
on Apr 3, 2018 at 6:47:38 am

The MXF's that Avid creates when it imports audio are identical to the original Wave Files if your project settings are correct with a couple of exceptions. That is if you have 24 Bit Audio Files and your Project is set for 24 Bit Audio then the main difference is they are now in an MXF Wrapper instead of a Wave Wrapper. The Exceptions are that Avid splits polyphonic files into multiple monophonic files. An 8 channel polyphonic file will be split into 8 monophonic files. Secondly the Avid OP-Atom MXF Files are usually slightly larger than the original file(s) because Avid adds some extra MetaData to them, other than that there is no quality loss at all as far as I've been told.

Yes definitely send all of the original files because most Audio Editors will want or demand they get them as well. There's a way in PT for them to expand the Audio Tracks and Link back to the Original Files if they need to. I wish I could explain this properly but I just don't know enough about PT to do that. Our Audio Engineer showed me how it's done and what the technique is called one day awhile back but for the life of me I can't remember any of it.

You probably already know this but another bit of info is the one thing that only Avid can do with Audio Files and that is the "Auto Detect Broadcast Wave Monophonic Groups". So this is a bit confusing but there are PolyPhonic P and PolyPhonic M files. A Polyphonic P file is a single file that can contain multiple tracks of Audio while Polyphonic M is a group of Monophonic files that make up a Polyphonic Clip. If the filenames end in _1, _2, _3 etc. then they are a Polyphonic M Group. If the "Auto Detect Broadcast Wave Monophonic Groups" is ticked Avid will import them as a single Polyphonic Clip. So say 70/1_1.wav, 70/1_2.wav, 70/1_5.wav and 70/1_7 are imported with this box ticked then a single Master Clip named 70/1 will import that has Audio on Tracks 1, 2, 5 and 7.

Our Audio Engineer insists that all on set Audio is Recorded as Polyphonic M Groups. There are a few reasons for this. Firstly if a Polyphonic P file is corrupt then you lose the entire Audio Clip but with Polyphonic M Groups you would generally at most have one corrupt file so all the other channels can be salvaged. Second is for the same reason why Avid splits Polyphonic P files into multiple Monophonic files and that is because it's easier to playback. Avid and PT only need to playback the Audio Files that are cut into the timeline and do not have to demultiplex a bunch of Poly P files on the fly while playing back the Video. One would think that demultiplexing audio files wouldn't be all that taxing on our multi GHZ computers but when there are hundreds or thousands of Audio Files in a Sequence or PT Session then it can make a fair bit of a difference. Lastly but not as important is to keep the size of the Audio Files folder down in PT by not including unused Audio Files.

Hope this makes sense and I apologize for making you read a novel.

"MY MEDIA/PROJECT MOTTO: If you think three copies of your Media or Projects are enough. Take a moment to place a value on them and then maybe add two more. Hard Drives are now stupidly cheap. A RE-SHOOT AND YOUR TIME AREN'T."


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Ben Harris
Re: Audio; AMA-link or Import
on Apr 3, 2018 at 9:18:42 am

No no don't apologise at all, that was very helpful and informative. Unfortunately are On Set Audio has already been recorded and I don't appear to have any Monophonic files from our sound recordist so I guess we'll take what we've been given but this is good to know for the future.

As for our workflow I think we'll go with the suggested import as MXF and can send to sound engineer with MXF/WAVs with AAF when it comes to the mix.

Thanks for your help.

Ben


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Brent Marginet
Re: Audio; AMA-link or Import
on Apr 3, 2018 at 2:45:39 pm

Just one last thing. Not all Audio Engineers want Polyphonic M files and there are a lot of Audio guys that have no idea how to setup there recorders to create them. Many of them don't have a clue what your talking about when you ask for Polyphonic M Files.

I just simply ask for the recorder to be set to record individual files for each track of audio and explain about the files that have _1, _2, _3 etc. in there filename if they give me the deer in the headlights look.

"MY MEDIA/PROJECT MOTTO: If you think three copies of your Media or Projects are enough. Take a moment to place a value on them and then maybe add two more. Hard Drives are now stupidly cheap. A RE-SHOOT AND YOUR TIME AREN'T."


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