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strange audio when exporting Quicktime
Hi all,
I’ve had some strange issues when exporting Quicktimes recently – namely, I’m finding that stray audio from the wrong part of my sequence is showing up elsewhere. It’s a 2-hour sequence, and on different exports (of different cuts of the sequence), different audio clips have been the problem, appearing in different parts of the sequence. There are no stray clips within the sequence itself, and otherwise the audio is fine – just with extra bits of audio occasionally appearing also in the wrong location.
A few items I think are probably relevant here:
1. It’s an anamorphic SD sequence of a 2K Red sequence (I’m exporting it to put on DVD). I’m dragging the entire Red sequence from the browser to the SD sequence and then exporting a self-contained Quicktime for conversion in Compressor.2. Audio immediately says it has to render when I place it in the SD sequence (though it doesn’t have to render in the original sequence), and rendering audio only is estimated to take an absurdly long amount of time (i.e. days).
3. Ergo, I’ve been skipping the render and just exporting a self-contained Quicktime and letting it render as it exports.
I feel like #3 is probably important, but because there seems to be no rhyme or reason as to where the issue will occur within the sequence, I thought I’d check for some confirmation here first before assuming this will fix things.
What should I be doing differently? Rendering the audio in the SD sequence doesn’t seem to be a reasonable option, and I suppose I could copy all of the audio files from the original sequence into the SD sequence instead of dragging it in from the browser, but would this actually solve the problem?
Thanks so much for your advice.
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10 Replies
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Are you saying that the stray audio is coming from continuous clips which suddenly play the wrong sound – i.e. that this is not a case of the stray sounds coming from clips which were never there in the first place?
For instance, the clip is playing some dialog and suddenly – while the same clip is playing – you hear sound which should not be there replacing it, or that the clip suddenly goes insanely out of sync?
If this is so, it is caused by the Brass Band Effect in FCP.
This was named by me when I was editing a sensitive drama some years ago and people would be talking on the track in hushed tones. All of a sudden a large brass band would blare forth for a while and then disappear.
The Brass Band effect is caused by an ancient bug which occasionally reappears if you import audio either recorded at the wrong rate, or in some format which FCP does not particularly like that day. The only cure is to export the offending sound clips as QT audio files and then replace the bad clips with the QT files.
If this is indeed a case of Brass Band syndrome, this corruption will continue randomly until you do something about it.
Best wishes,
Harry.
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Hi Harry,
Thanks for your response. The stray clips are there in the sequence, but they’re actually from a whole continuous section of audio from a totally different part of the sequence. Playing the original sequence in FCP, you don’t hear it at all. (I can’t speak for the SD sequence I’m exporting because of the aforementioned ‘6 days to render this audio’ issue.) But if you export a Quicktime, there it is…
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Kathryn,
Clearly no Brass Bands involved here.
I don’t understand why you are not exporting your original Red sequence as a self contained movie and then taking that to Compressor and thence to DVD. Why this step of dragging it into an SD sequence? You must have some reason for this extra step. Is there an alternative?
I assume you’ve done all the usual stuff like trashing prefs, running Disk Warrior and throwing the mouse at the wall?
It must be some disgusting corruption somewhere. How about downloading the demo version of FCP Maintenance pack?
Harry
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Ah – I just re-read your original post. The unwanted audio is only audible when you do a QT export.
This is what we call the Bonkers Effect. The cure involves trashing prefs, running Disk Warrior and other fix-it software, throwing mouse and ultimately giving up and reinstalling FCP AFTER you have REMOVED FCP TOTALLY by using “FCS” or FCP remover, available free.
I suggest you do all these things before you go into the last stages of the Bonkers Syndrome, which involves contacting Squeaky Fromme and asking her to move into your spare room.
Harry.
Let me know what you decide to do.
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Another thought: are you experiencing freezes? If you are, go to your System Prefs and set your screen clock to display seconds as well as hours and minutes. If, during the FCP freeze-up, the seconds continue to tick, the problem is not within the system and is FCS related.
I suggest a re-install. You are clearly wasting a whole load of time on this. A REMOVAL (FCP REMOVER) and reinstall will probably be worth it.
Harry.
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Hi Harry,
Yes, unfortunately mouse-throwing has proven surprisingly ineffective on this matter. My working theory is that there is something about dragging in the audio from the other sequence rather than cutting and pasting all of the individual audio clips into the SD sequence that is confusing FCP. Sadly, proving this theory will involve many hours of watching the entire DVD…was hoping to find a rational X=Y type rule to go by.
(As for the workflow, my tests on this project showed me pretty conclusively that the picture quality was significantly better when I let FCP do the downscaling rather than exporting a native Quicktime and leaving it to Compressor. Counterintuitive, but there you are…)
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Kathryn,
I am almost certain that this is due to a mis-match of audio sample rates.
Suggest you go to your SEQUENCE SETTINGS and see what the audio rate is for your RED sequence. Then look at the rate of your audio recordings. If they are not the same, then this is the cause – or one of the causes.
You are only having problems with the audio, correct? No other odd behavior?
Best
Harry.
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No freezes (yet). Yep, this is the only issue (thus far) and it’s audio-only. Your suggestion about the audio sample rate mismatch is a good one and would certainly explain things. I hope you’re right, as I can think of better ways to spend this weekend than dismantling the machine and re-installing the program.
Not at the relevant machine at the moment, but will work on it this evening and will certainly update you with progress (if I make any) if you’re curious.
Thanks again for your excellent suggestions.
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Oft repeated mantra here on this forum is 16/24 bit 48 khz PCM (either wav or aif) in FCP with sequence set to 32 bit 48khz. This is the only reliable way to do audio in FCP. File formats like mp3 and sample rates that do not match the sequence are a no-no.
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My much-belated thanks to you both: the magic answer was indeed an errant mp3 that somehow managed to sneak its way into the sequence. Nowhere near where the problem occurred in the sequence, but once we replaced it it was no longer an issue. So thanks again for reminding me to check.
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