Final Cut Pro Sample Rate issues - out of the blue.

Chadfish

Chadfish

Veteran
I've been working in FCP for years, and never had a problem with audio until today. I captured some EX1 footage for a spot and it played fine. I exported the audio from that and used it in a multitrack Cubase project to make the final audio for the spot. I usually make 16 bit, 44.1k mastered audio files (not 48k because they do dual duty as radio spots) and drop them in the FCP timeline. They always play fine. Today they played slow as if the FCP timeline was forcing them to play at 48k. I've always been able to do mixed sample rates. I set the Sequence sample rate to 44.1, and it plays fine, but the original camera audio plays slow still. Very odd. I export at "Current Settings" and it sounds ok, but when I export at 720/30P (no change in audio settings mind you) that file plays back slow. Odd

I even opened up an old project in standard def. Audio played fine. I remade the audio file to update the spot, and again it played back slow. I changed the sequence settings to 44.1 and it played correctly.

This is an issue because camera audio is 48k, while music from libraries is usually 44.1. Now it seems I have a sample rate conflict going on, and I think it's final cut Pro causing the trouble.

Has anyone encountered this? Any suggestions?
 
Hmmmm, Humboldt county and 44.1 files clocked at 48 sound slow.... Are you sure you were using the good stuff?


OK. 44.1 clocked at 48 will play fast not slow. Before I talk about poss causes I will pause to say, mixed sample rates- bad. Forget what Apple says you work in sound so you know better, just say no. Second digital video is at 48, deal with it. Your on an 8 core for god's sake how long can it take to convert, less time than it took to think about not converting.

What may be happening is that you have something set to digital in in your audio chain. If your interface is clocking to a digital input, and and that input is getting a 44.1 signal, and since your studio is using both I would say that it's quite possible, then the interface will clock out audio at 44.1. Now you dropped a 44.1 file in a 48 timeline so FCP is converting on the fly (see how hard the conversion process is?) so now your 44.1 file is playing out of FCP at 48 and hitting an interface that is clocking at 44.1 and guess what it plays slow. I feel like Tom Lehrer singing "new math". I could be wrong but that's my guess.
Cheers
SK
 
Anything plays slow. I tried a new peoject and threw a NTSC video file with 48k audio, and it played slow. I changed the sequence to 44.1 and it played normal.

Odd. It may need a reinstall.
 
Maybe I wasn't clear. If you have a 44.1 digital signal feeding a digital IN on your audio interface it will force it to clock at 44.1. So yes anything that is trying to play at 44.1 will be fine anything trying to play at 48 will be slow.

Disconnect all the digital cables that connect to your interface or just disconnect the interface and use the computer speakers. If that gets your 48 stuff playing at the right speed then that was you clocking issue. This is almost certainly NOT a software issue and reinstalling won't fix anything unless along the way you also disconnect that digital cable from ?? the CD player that is clocking your interface.

Something else that is the same issue with a twist is that a lot of digital devices will toss out completely bogus signals when turned off. So if you have a digital in (on your interface) connected to say a DAT deck that is turned off you can have playback either really slow or sometimes really fast. QuickTime video and audio are not nec clocked in a coordinated fashion, in fact if you have an interface they are not coordinated at all. So it's very simple to clock them at different rates and get the kind of problem you are seeing.
 
Thanks Noiz2

I'll do some plugging and unplugging. My motu is running on bus power and has been for the last 2 years. I was having issues certain times when my audio would drop out upon changing sources (Finder/FCP/Cubase/Quicktime player etc., but that has gone down substantially since I got a dedicated firewire PCIe card. Anyway I'll do some poking around. Thanks for reminding me to test the hardware before I mess with the software.
 
Hey Noiz2

So I tried setting my mac to play all audio through the internal speaker, and turned off my audio interface, and did a restart to ensure all settings were fresh. I then opened up an old FCP project I'm sure worked when I made it, and that was (they all are) set to 48k. Still plays slow until I reset the sequence settings to 44.1. Same thing with a new project that I drop NTSC or HD video onto. I do get a red "needs render" line above video I drop into the timeline, even though it's set to the same settings as the video. The render alert goes away when I set the sequence to 44.1

I have nothing digital going into my audio interface anyway. So it's odd. Nothing in my workflow has changed. No software updates. No new gear. It just happened during editing of a TV spot using footage from my Sony EX1, which I have done a lot.


Have you any other possible scenarios that may cause this? Anyone?
 
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