In desperate need of help! Final Cut Pro suddenly distorts audio!??

Hi
I have filmed much with my 7d using a juicedlink mixer and imported it into final cut pro.
Suddenly when I am editing the sound gets distorted and really high even though the sound waves look fine. It happens mostly in transitions on all my timelines. Here is a video clip of the phenomenon: [enelesfilm.se]
Look at the audio meters Why is it like this and how do I fix it?!
Thank you so much for any help!

Are you cutting with native H.264s out of the 7D or did you transcode to ProRes or something else more edit friendly before editing? H.264 is pretty to look at and has lovely small file sizes, but it's not reliable for editing. Glitches and hangs are common, in my experience.

You could try doing an audio mixdown - go to Render > Only > Mixdown audio and see if that helps.

I haven't seen that phenomenon in a looong time...so maybe it's an old problem arising in new ways. I'd try the usual -- dump preferences, Audio Mixdown, and also disconnect/reconnect media. Check on Jude's comment about using H.264s directly (the simple answer is always, "don't". The fact that it happens on transitions also suggests render-file problems to me.


www.derekmok.com

Ha! This one again!

I had this years ago - Sudden Explosive Sound Syndrome. It's one of life's great mysteries. I should take Derek and Jude's advice.

Do you also get that thing where one of your tracks is suddenly playing back something completely unrelated - like a Brass Band VERY LOUD? I found that these two effects tended to go hand in hand.

Hugs

Harry.

Thanks guys! I will try your suggestions. I am working in ProRes and no Harry323 I havent had that problem. I'll tune in when I have tried it out

What is the sample rate / codec of your audio? I see dark green lines at the top of your audio files. You may want to check if your sample rate is 48k and the audio is uncompressed PCM audio.



www.strypesinpost.com

"Do you also get that thing where one of your tracks is suddenly playing back something completely unrelated - like a Brass Band VERY LOUD?"

i haven't experienced Sudden Explosive Sound Syndrome,
but i have had my audio appear to be messed up, playing the wrong things.

the problem there was in the render files.
FCP had rendered the wrong sections of audio.
from memory there weren't too many filters on those tracks so it may have been part of an audio mixdown.

deleting the audio render files fixed the problem.


nick

> i have had my audio appear to be messed up, playing the wrong things.

Usually switching to only Audio Mixdown for audio renders reduces the frequency of this problem for me, but doesn't eliminate it.

Also, for the last two months, one particular personal project file in my vault has had this problem with frightening consistency. The project itself is frighteningly consistent -- it's updated every one to four weeks, always adding eight new sequences, with DVCPro HD 720p24 video synced to 48kHz WAV files from a secondary source, a Zoom H4 audio recorder.

And on almost every update since November, one of the seven -- no more, no less -- would have that audio render switcheroo...usually the fifth one, if I remember correctly. This project file did not begin life with this issue, even though prior to the issue the specs for the media are still the same. In all cases, ditching render files didn't help, and I have to disconnect media on the WAV, reconnect and then re-render, which fixes the issue.

The consistency of that leads me to believe that the project file has something inherent in it causing the audio-render issue -- like the project file acquired a "bug" somewhere during the project file's eight-month lifespan.

At some point, just for fun, I might flush the project file with an XML export or at least a copy-repaste just to see if the problem goes away.


www.derekmok.com

Ahhh the Manly Ferry. Makes me home sick

looking at the lines at the top of the audio files I see there is a line on the first clip played but not on the second so I would say it is a mis-matched sample rate. The clips with the lines do not match the sample rate of your session and need to be rendered.

Quote
Frank
Ahhh the Manly Ferry. Makes me home sick

you from Sydney Frank?
that's where i live, and yes i always feel good flying back into town.


nick

I'm originally from Manly too. Love that ferry ride at night with the seagulls flying right along side hunting for squidlets... ahh now I'm homesick for it too.

I was at the office today and trashed my preferences, deleted all renders from the render manager. It didnt work so I tried the audio mixdown and it seemed to work for at first as you said but then the problems appeared again. Also the copy-repaste in a new project didnt work either The clips with 50050Hz must be the ones I conformed from 24fps to 25fps with Cinema Tools. Thanks alot for your help, what do you suggest I try next

That explains the dark green lines at the top of the audio clips. Are you trying to match the framerate to footage that was shot in 25 fps? Can you edit at the native frame rate of your source footage? FCP doesn't like non standard audio sample rates. Some suggestions to fix it (make sure you do a test before proceeding, and this is assuming you have to cut in 25fps)-

1) batch export all your source clips so FCP resamples the audio, then re-link the files.

2) export the audio files as Wav files and sync them up with plural eyes (I haven't tried using plural eyes with wave files, so test).

3) conform the original clips to 25 fps in compressor instead of going through cinema tools.



www.strypesinpost.com

Blast from the past - this has come up before, and it has happened to me. Bizarre solution (for some, anyway) is to reset your Easy Setup - change it to something else, then back again. It makes no sense, but neither does the problem itself. can't guarantee it will work in your case, but easy enough to try.

Scott

That happened to me a while ago a few times. Had to dump all the render files and in one case re-install FCP.

Your first suggestions seems like a nice option. I will try it first

Nick Meyers Wrote:
-------------------------------------------------------
> > Ahhh the Manly Ferry. Makes me home sick
>
>
> you from Sydney Frank?
> that's where i live, and yes i always feel good
> flying back into town.
>
>
> nick

Original from Brisbane but lived in Sydney for a while. Been in Los Angeles now since '94.
Funny thing was I had lived in Sydney and later travelled there for work every year for 5 years and had never taken a ride on the Ferry until I was back there 2 years ago with my wife and son as "tourists".

Is that the same ferry we have on lafcpug front page? [www.lafcpug.org]

Michael Horton
-------------------

Michael Horton Wrote:
-------------------------------------------------------
> Is that the same ferry we have on lafcpug front
> page? [www.lafcpug.org]

It certainly is. Except I think the bow numbers have been changed

it sure looks like one of the Manly ferries, it could be the "Freshwater" or the "Narabeen", (except of course it's the "Lafcpug"

it's a great ferry to ride, just for the sake of it, as Jude and Frank mention.
like the coast walk from Coogee to Bondi Beach, one of the great things to do in Sydney.
although you wouldn't want to have been doing it this day:




(apologies to Simon for the hi-jack)
nick

Y'all make me feel like an Aussie. Cheers Mate

Michael Horton
-------------------

Im wondering about your first option. Will the quality of my LT clips get much worse when converting them to LT again? Is there some way to bypass the video maybe?

As I have many clips with 50050Hz scattered all over my project I would love to be able to do this with a smart batch of some kind. Any suggestions?

Or just a quick way of finding all these 50050Hz clips in my timeline?

>Will the quality of my LT clips get much worse when converting them to LT again?

If you choose recompress all frames. Not sure if the audio will be converted if you dont check that option.

How to quickly find those clips? See that dark green line at the top of your audio clips? Those are the ones.

One more thing. What happens if you switch audio playback quality to high in user preferences?



www.strypesinpost.com

I jsut get "general error" when I try batch export. I found an easier way to find all 50050Hz clips. In the browser you can sort clips by their item properties.

Actually setting it to High seems to work so far! I havent tried much but it really seems to work - much easier than needing to convert

I will post back how it goes

You guessed correctly Nick - that was the Freshwater - I did that pic years ago. Freshwater is also my favourite beach in the whole world.

Mine's Palm Beach NSW

All the best,

Tom

No distortions have come up when I tried playing for a couple of minutes. You saved my ass Thank you Strypes!!