FCP X exported quicktime movie: distorted audio

Now this was a head scratcher today. We did a tiny little music video for private use and fun (isn't that what most editors are using FCP X for these days anyway?).

When it was time to export the movie (just music - nothing else), the exported movie had distorted audio. I sounded heavily compressed with drop outs. Levels of the project were more than fine in FCP X. Not even orange. The garbled audio was a result of "export quicktime movie" - same as source (which was ProRes). I tried export audio - same result. Then I tried "sharing for Apple devices" and also through Compressor - now those two attempts didn't even get through the movie. I got a quicktime error -50 each time.

Quite embarrassing. Apple kills FCP 7 and the new X can't even do a simple movie export right. Has anyone been able to export a clean sounding quicktime movie? This almost looks like some kind of bug to me.

By the way - I had to pull the exported ProRes video into FCP 7, recut the music and export from there - without any problems of course....

Thanks for your feedback.

--- Markus ---

How loud were your audio peaks? On most video systems, line up tone is assumed to be at -20, so you'll be distorting by the time you hit -6dBs. You could try exporting an OMFFFFFffffffff.... I mean... well... try waiting a few months to see if Apple finally supports omf/aaf exports. That or shell out $500 for Automatic Duck to get your audio to the sound department.



www.strypesinpost.com

Very funny...

First of all, as an experiment I just dragged a song purchased on the iTunes store into my project - no wait, event - I mean, timeline. The levels of the unmodified m4a file were of course maxed out - as is the case with most commercial tracks. So, out of caution I dragged the volume down quite a bit, so that the peak levels barely hit -6 dB. Nothing distorted when I played the project (sequence) back in FCP X. The exported quicktime movie also doesn't sound like audio clipping. More like damaged audio with muffled quick sound drops throughout the entire piece.

When I created my project, I mean, sequence, this stupid surround sound option was turned on by default (who at Apple thought that every DSLR-shooting editor wants to do his youtube/vimeo videos in surround sound?!?!?!?). Maybe that had something to do with it. I'll have to investigate this.

In the meantime - I'll call this one a major export bug.

Just did another little experiment:

I started a fresh project. Dragged an m4a audio clip (iTunes Store) into the timeline. Settings are left at default (surround, 48kz ProRes).
The timeline contains only one audio track. No video clips.

Now I exported the project as audio only and chose AIFF as my export format. FCP X hangs after 10 seconds. Cannot finish the task.

There seems to be a serious bug with exporting audio that was in the m4a format.

> The exported quicktime movie also doesn't sound like audio clipping. More like damaged audio with muffled quick sound drops
> throughout the entire piece.

.m4a music files purchased from iTunes Store have copy protection on them. Did you try an AIFF or WAV? A professional audio format?


www.derekmok.com

Only m4p files are protected.

This issue may be something to do with the fact that you only have audio tracks on your timeline. Try adding a black solid generator for the entire length of the song and see if that makes a difference.

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Jon Chappell Wrote:
-------------------------------------------------------
> This issue may be something to do with the fact
> that you only have audio tracks on your timeline.
> Try adding a black solid generator for the entire
> length of the song and see if that makes a
> difference.

Thanks for all your suggestions. It did some further systematic testing.

It was not the fact that the audio file was the only file on my timeline. There are two bugs going on here.

BUG #1: on "export audio" of a project, FCP X hangs on the very last few moments before it's done exporting. Like in my picutre above. Hower, it still exports the file. It just never tells you it's done. Buggy indeed.

BUG #2: if your timeline is set to the default "surround" and you cut with an m4a audio file (from iTunes) - when you try to export that timeline, either as an AIFF audio export or as a quicktime movie, the audio of that m4a section of the resulting file is distorted/compressed/garbled.

My audio exports sounded fine when I set my timeline to stereo. Same m4a file. Only stereo timeline, not surround. There was also no distortion with a surround timeline when I replaced that m4a file with an AIFF convertion of the same clip.

So it's the combination of m4a and surround.

Under normal circumstances I would never work with an m4a file and I would not set my timeline to surround. It's only that Apple decided for some strange reason to make "surround" the default audio channel setup of every new project. Plus, they expect you to simply drag in any audio from your iTunes library through their built-in music/sound browser. And that's exactly what's their "FCP X target audience" is most likely going to be doing....