Major bug: Audio Levels incorrect on export

Question

Level 1

20 points

Major bug: Audio Levels incorrect on export

Here's what I'm trying to do and the frustrating results I'm getting. The idea (and the client's specs) is to export a ProRes file with discrete audio channels. 24 in my case each being a discrete mono track. We've been doing this in FCP7 over 4 years now without any issues. When trying to replicate that same workflow inFCP X, I get incorrect results. So I ran a quick test to see if FCP X is messing with audio levels on share or export for those of us who deliver to the gazillion providers other than YouTube.

In FCP X, I import a mono (not stereo or dual-mono, just plain mono) reference tone at -20 dBFS. My project is set to surround (this is for multichannel projects).

In the timeline it plays at the the correct level" -20dBFS and all looks and sounds good. My file is 24 bit 48kHZ so is my project. I also have FCP X being monitored through a Videotek for measurements.

The imported tone is measured and confirmed to be at -20 dBFS on the Videotek, as well as in Audition CS6; straight from the file to eliminate any patch cord speculation:

I assign a role called TONE to the audio clip and export role as separate file.

With PAN MODE set to NONE and channel configuration set to MONO I get an exported audio file that is 2.67 dB quieter than my original file.

So I try a different approach: I set PAN MODE to Default and channel configuration to mono. I get a file that is 6.02 dB quieter than my original file.

So last try: I set the channel configuration to CENTER and the PAN MODE to NONE. I get another file that is 6.02 dB quieter.

The logical outcome even with pan laws in mind, should be: you import an audio file at -20 dBFS, you verify that the audio levels are correct with the audio meters, you export it and you get an identical -20 dBFS audio file.

I do this all the time in FCP7: you set your audio channels to mono and set the pan law to 0 dBin your sequence settings. done.

So what is going on in FCP X? I know a whole bunch of post houses deliver files for broadcast. Do they all have these incorrect levels? Or do the editors compensate with a gain of 2.67db or 6.02 dB according to the audio configuration. Which mind you is unacceptable because if the FCP X meters say my reference tone is sitting at -20 dBFS then my exported file should be -20 dBFS not some arbitrary number.

I ran this test on multiple machines: MacPro Mountain Lion 10.8.2, Macbook Pro ML 10.8.2, MacPro Snow Leopard 10.6.8 and I get the same results.

Anyway, I'm really suprised that on this board I only found a handfull of threads that mentioned this issue. None had any solution or explanation for this behaviour on export. Yet, it is a pretty serious one. Am I not doing it right? But then I had other people try on their own and they are reported the same thing.

Any light shed on this issue would be most appreciated. Until then, FCP 7 and Pro Tools are my only hope.

Final Cut Pro X, OS X Mountain Lion (10.8.2)

Posted on Nov 4, 2012 1:31 PM

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Answer 1

klod Author

Level 1

20 points

Nov 6, 2012 4:30 PM in response to James Cude

James,

I'm not concerned about routing. The issue is the drop in levels on export. Please see the last example and image I posted above: it clearly says that I routed to center yet the level drops on export.

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Answer 2

klod Author

Level 1

20 points

Nov 7, 2012 1:57 PM in response to Wild Giles

Yes I've sent a feedback to Apple already. I was just hoping someone had a viable workaround for this issue that I haven't tried yet. Compensating by odd value is not a solution either because I just realized there is no way of boosting your audio clip by decimal values. You can only adjust your audio clip levels using integers.

64 bit audio mixing should in no case affect the export levels. Logic Pro 9 (Apple's own), Nuendo, Cubase, Studio One, Cakewalk all have a 64 bit audio engine and none mess your levels on export.

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Answer 3

joen

Level 1

9 points

Jan 21, 2013 12:33 PM in response to klod

I have had the same issue. Exporting roles changes the levels. I have no solution or suggestion unfortunately, I can just confirm that exporting roles does not behave as expected, as far as I can tell.

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Answer 4

May 4, 2014 8:36 PM in response to klod

Hello,

Did you ever get any feedback from your issue? I have been having this issue in a pro environment since it came out.

On my end nothing fixes it except addiing a Gain filter and adjustments from there.

I know this was an old post but was just interested if any updates were found.

thanks,

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Answer 5

klod Author

Level 1

20 points

May 5, 2014 11:43 AM in response to Michael Meis

Hi Michael, the last I heard from Apple is that they seem to think that when you're trying to export audio roles as discrete channels you're actually doing a mixdown hence the level compensation to avoid clipping (?!??). Which of course, I tried to tell them was wrong because we're not doing mixdowns but a 1 to 1 copy of audio tracks to the mov wrapper. What comes in goes out the same. Audio should be left intact, just passed through with identical levels. Also, I pointed out that it works perfectly in Final Cut Pro 7. However, I don't think they get it. I haven't heard from them since. To do the job for our clients, I edit in FCP X, export an mov ProRes, bring into Pro Tools adjust levels to specs, export audio and add to the mov wrapper in Quicktime Pro. That's 3 apps for the job of one. Yes, I've tried the gain filter but it only gives one place after the decimal and I need two to compensate. Example Apple drops the levels by 6.02 dB the gain filter only does 6.x. not 6.x.x. The broadcasters have pretty stringent specs especially that CalmAct ATSC A/85 and EBU-R128 have been made mandatory by some providers. I had work rejected for .02 dB. So I can't have levels being messes with by FCP X. Lately, I just gave up on FCP X and do the work in FCP 7. Please submit a bug report to apple developer's bur reporter. The more it is mentioned to them, the better chances of them finally realizing that it is wrong.

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Answer 6

Oct 14, 2014 7:28 AM in response to klod

The only thing I can add to this is that when exporting using roles as a multi track QuickTime, a stereo project will export with -3 DB, where as a surround project will export at -6 DB. Perhaps if there was an option for a mono or discrete project this wouldn't be an issue but unfortunately that is not the case. It does this because it thinks you are mixing down stereo pairs to mono channels (which you would want to lower -3db) or Mixing down surround to mono(which you would want to lower -6db) Hopefully this is something they will address in the next update, as it's incredibly annoying. If they just were to add an option for a mono/discree project, then it wouldn't feel the need to mess with our levels. Please fix this Apple!

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Answer 7

Jul 13, 2016 7:04 PM in response to klod

I've got another thing to add here (just submitted to apple).

It seems that some parameters of audio effects applied to an audio clip in an angle in a multicam clip (such as the Balance or Mono parameters of the Logic Gain plugin) are played back properly in the Multicam clip editor, but have *no* effect on the audio when the Multicam Clip is "shared" as an AIFF file or when the Multicam clip is used in a project. Oddly other parameters in the very same plugin instance (such as the Gain parameter in Gain plugin) *do* have an effect on the resulting audio when the Multicam clip is shared or played from within a project.

This is a rather absurd bug - and may explain some of the issues folks are having here - ?. Not sure, but it certainly explains issues I've been having with trying to do simple mixes in FCPX.

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Answer 8

Jestersz

Level 1

4 points

Jul 21, 2016 11:55 AM in response to klod

This is still a problem... Currently running 10.2.3

As a note, if you export interleaved files, everything is perfect.

Too bad the network I work for can only take discrete...

If anyone has any work around to date, post it up please.

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Answer 9

Jul 21, 2016 3:04 PM in response to Arvid Tomayko-Peters1

I have noticed this problem as well. Ive been searching all over the web for help and nothing so far.

Hope they fix all this, it's really annoying adding a limiter to your multicam clip and then having audio clipping after it is used in a project.

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Answer 10

James Cude

Level 4

1,587 points

Nov 5, 2012 10:00 AM in response to klod

If I set the Audio Channel Config for the mono clip to "Center" the export routes properly- does this work for you?

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Answer 11

Nov 6, 2012 8:14 PM in response to klod

Best to send Feedback to apple on the issue as there should be no difference in a direct export of the sound from what the lvl's show in FCP X. Keep in mind that FCP X edits in a 64 bit audio space.

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