FCPX introduces audible pops into footage!

Question

Level 1

9 points

FCPX introduces audible pops into footage!

One thing first, I upgraded to Lion yesterday, and am not sure if this has anything to do with it. Now, what I'm basically trying to do is compile four :30 second spots together on a timeline to create a two minute clip. I did this before a week ago, basically drag the finished movies into the timeline one after the other and hit render; not much science to it.

Now, when I try to do this with my new clips, it introduces an audible popping and crackle, much like when a DAW (Logic or Live) drops audio samples when the CPU is pushed too hard. These are four pre-rendered clips, so there is nothing else going on in the project, and the clips themselves play perfectly fine in Finder. I've tried restarting, deleting project, creating new projects with different settings, etc., and same thing. Any ideas? Thank you in advance!

MacBook Pro, Mac OS X (10.7)

Posted on Jul 26, 2011 8:30 AM

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Answer 1

djoliverm Author

Level 1

9 points

Jul 26, 2011 8:38 AM in response to djoliverm

OK, so I tried importing other clips that I know work alongside the ones that don't (i.e., no pops) and they work, just these particular files don't. I'm going to re-render the files in question (although by themselves they're perfectly fine) and see what happens.

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Answer 2

djoliverm Author

Level 1

9 points

Jul 26, 2011 8:56 AM in response to djoliverm

So I re-rendered one of the clips and apparently it's fine when it's put back into FCPX. I've been having several issues with FCPX rendering with Compressor settings, getting first rendering issues (transitions wouldn't render correctly) and now this audio hiccup deal. Anybody else having issues like these rendering in FCPX and Compressor?

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Answer 3

djoliverm Author

Level 1

9 points

Jul 26, 2011 9:00 AM in response to djoliverm

So I spoke too soon! It seems that FCPX plays back the file perfectly fine UNTIL the program does the transcoding and analysis, THEN it starts with the pops and crackle. Any suggestions?

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Answer 4

Jul 26, 2011 9:27 AM in response to djoliverm

I actually had a similar problem with FCP7 actually. It kept adding an audible popping sound to the music track everytime I imported the song into FCP even though the song played fine in quicktime, VLC, and iTunes. The way that I got around the problem was I used iTunes to convert the song into a different format and then re-import it.

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Answer 5

djoliverm Author

Level 1

9 points

Jul 26, 2011 9:44 AM in response to MrPrezident0

Hmm, the thing is that this is a video file. It's the audio track of a rendered video file. I tried exporting it as a .mov and importing it back (I was working with .mp4 files before) and same thing. The popping happens AFTER it analyzes the video. I'm wondering if I can cancel the analyze video and make sure it doesn't analyze it...

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Answer 6

djoliverm Author

Level 1

9 points

Jul 26, 2011 9:59 AM in response to MrPrezident0

So I found out that if I just cancel the analysis of the file it's fine (which is OK since these are finished files; no need to analyze them). Now I'm having an issue with one in particular that just doesn't render the first transition properly, so I've deleted all render files and am re-rendering it to see if that gets it working. Hate all these glitches! ;(

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Answer 7

djoliverm Author

Level 1

9 points

Jul 27, 2011 8:58 AM in response to djoliverm

So I think I figured it out! (I'm pretty sure FCPX + Lion has issues with compressed audio formats, ESPECIALLY AAC and Apple Lossless!) There's a video of my findings below:

1. I tried doing exactly the same thing I was trying to do on my machine on a co-worker's Snow Leopard MBP, and it worked out fine (it was just importing an iPhone 4 .mov and exporting it in FCPX). The output file was pretty much the same as what came in.

2. I found out that only movies from my iPhone 4 were coming out all crazy in the audio, yet my Canon T2i files were fine. Both are H.264, yet the Canon T2i records audio as Linear PCM, while the iPhone 4 records audio as AAC.

3. So I got an idea to use screen flow to record a youtube video and record the computer's audio. Then I decided to export with different formats, both as HD NTSC standards and as web standards with H.264.

4. I found out that both NTSC and H.264 standards were perfectly fine, SO LONG AS THE AUDIO WAS LINEAR PCM (or uncompressed!).

5. I then exported the same clip (both times as H.264) and ONLY changed how the audio was rendered (either Linear PCM/Uncompressed or AAC) and VOILA, I got click and pop artifacts ONLY in the AAC version. The ones that were output as uncompressed audio were totally fine!

CONCLUSION:

Final Cut Pro X on OS X Lion has issues with compressed audio, MAINLY AAC and Apple Lossless! Anything that is Linear PCM/Uncompressed should be fine! For example, MPEG 4 AAC Enhanced Low Delay at 320K came out 95% OK, one or two clicks.

So if any of us are working with material where the audio came to us already as AAC (like an iPhone 4), then we have to rip the audio out somehow first (like through VLC for example) and import it separately as an uncompressed file.

Here's a youtube video showing exactly what I'm talking about:

http://www.youtube.com/watch?v=FDw4btShH0s

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Answer 8

FBC_21CA

Level 1

23 points

May 20, 2012 11:55 AM in response to djoliverm

I'm having the same problem, but the audio has never been anything other than Linear PCM, the video is all Prores 422 and I'm using Snow Leopard. So maybe it's a larger issue.

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