itaro

Maintaining timecode after processing M/S to stereo Recording in Pro tools.

7 posts in this topic

Hi there,

For a shooting tomorrow, I will be using my M/S rig (Sennheiser MHH30+MKH8040) to record stereo using my Sound Devices 744T, after the shoot I will have to decode all the files in Pro Tools to a normal stereo files and send them to the video editor. Is it possible in Pro Tools (Vanila 11.3) to decode those files to normal stereo while maintaining the original timecode?

Hope it all makes sense, any help will be appreciated!

Itse

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Sorry, but again reading the manual would have been helpful. Input Linking. No need to do the converting in PT.

PT won't preserve metadata since it writes a new file.

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:) thanks again pkautzsch!

Indeed, I've read the manual more then once, but when I've recorded files previously with my M/S rig without input linking and imported them to PT in order to convert them to normal stereo files, I had to lower the 2 side channels about 6db to have the right stereo image.

Was it right?

Or when decoding the channels, the mid and 2 sides should all be on the same level? I know that I can mix the width of the stereo field to my taste but is there a fixed level for setting the M/S conversion?

thanks.

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When you import the files into Pro Tools, spot them to their original timecode position on the track. This will place the files at whatever timecode position you recorded them at. 

Then you can decode as you wish. If you use a plugin to decode, route that track's output to a new audio track. If you decode old-school with aux channels, route those outputs to a new stereo audio track. Then simply record the decoded files onto the new track at the same timecode position. This will create new audio files in the same position on the timeline (with the same timecode metadata) as the originals. Make sure your session is set to use WAV files of course.

Unfortunately this will need to be done in real time - offline processing and bounce to disk will not preserve the timecode metadata. 

-Mike

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But if you do link them at recording, you'll lose the ability to change the balance later. Why does the editor even need the stereo files? Can't they just use the unmatrixed files? Then all options are retained for audio post and you won't need to go through the lengthy ProTools process

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Mike, yes that would preserve TC metadata, but not all the other nice stuff in the BWF chunk, like comments, scene-take, circled takes, and so on. Of course, It Depends on the shoot if these metadata actually are being entered.

Constantin, why do you lose the ability to change balance? You can convert MS to LR and back easily. If they want less S, audio (!!!)
post can simply pan the LR channels a bit inward. Pan both channels to center, and voilà, you have the clean M signal. If they want "more stereo", there are many MS encoding/decoding plug-ins on the market. I would not rely on a picture editor (or low-budget documentary style all-in-one editor) to know how to decode MS.

Also, listening to LR instead of MS on location is way better to judge if what you do is workable for post.

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I would not rely on a picture editor (or low-budget documentary style all-in-one editor) to know how to decode MS.

Of course not. That's what audio post is for

Also, listening to LR instead of MS on location is way better to judge if what you do is workable for post.

That's what a headphone matrix is for
You can convert MS to LR and back easily.

Oh yes of course. Sorry, I was mentally stuck in that car thread...

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