44.1kHz & 48kHz Audio Files?

Hey!

Trying to solve a weird issue with a project I'm working on.

If I have a project set to 48kHz audio and drag a 44.1kHz audio file into it, it seems like FCPX automatically converts it to 48kHz so it plays correctly. Is that so?

Is there a way to override that? I want to add a 44.1kHz audio file, and I want it to play in the wrong speed!

Thanks

DZ

Never tried, but you could select the 44.1 (I didn't know they were conformed) in the Timeline, go to the Retiming menu, select "Automatic Speed". See what that does.

That does nothing

I've never put the two together in a Timeline raw before. But, I know in a Sync clip they drift out of sync over time. You can always manually change the speed of an audio clip (Cmd-R).

If you want a clip to play at the wrong speed use Retime and turn off pitch correction unless you want it corrected.

Trusty old Digital Performer fixed it for me. But it still didn't work.

Problem is that it needs to exactly match the audio from my camera, so retiming is not really an option. I was hoping that the difference was due to some original error in conversion between 44.1/48kHz, but that doesn't seem to be the case.

Thing is that it seems like the audio was played a tiny bit slower on playback (how the heck would that happen?). And the audio files I've been given doesn't match the audio in the footage!

Have no clue anymore what to do. Any suggestions?

Hi Dmitri,

First let's get something out of the way: when you drop a 44.1 KHz audio clip into a 48 KHz timeline FCP X does not do anything to it. So that's not the problem.

If you want we can have a look at the files. Drop the video footage on your timeline and export an audio-only file (48 KHz AIFF). Then send me the 48 KHz AIFF file and the original MP3 file so I can compare them, maybe we can come up with a fix.

ronnycourtens at mac dot com

- Ronny

OK, I'm confused. Do they match or not? Do you want them to or not?

Ok, here's the situation:

I film a lot of burlesque performances, sometimes live, but this time in a studio, but the procedure is the same:

I film the acts with 2 cameras. When it's time to edit, the girls send me the audio file for the music. As the cameras record the "live" sound in 48k I usually convert the (usually) 44.1kHz file to 48kHz before importing to FCPX. Then I make a multicam clip of the two camera angles and the imported audio file. I've made maybe 50 videos like this and it has always worked flawlessly.

Recently I shot four girls performing 5 acts in total in a studio. On one of those, the audio don't sync up! The audio from the cameras is slightly longer than the files I've recieved.
I first thought it could be some conversion between 44.1 to 48k that was the culprit. But after importing a 44.1k file I see that the difference of that is far more. So that's not the issue.

Now, my only theory is that 1) the girl sent me the wrong file even though she says it's the same 2) Her MP3 player somehow played the track to slow 3) Something else???

I think, but didn't pay much attention to it, that each girl played their particular song from their own phone or MP3 player. This one that doesn't work apparently has some cheapo MP3 player. Even so, it seems weird it would play in the wrong speed!? Maybe some conversion is going on when files are added to it?

ronny courtens wrote: First let's get something out of the way: when you drop a 44.1 KHz audio clip into a 48 KHz timeline FCP X does not do anything to it. So that's not the problem.

This seems not to be true.
When I have the same file properly converted to 48k then add the 44.1k version to a 48k project they match up. But when I add the 44.1k file that just has a 48k header (tricking FCPX so it thinks that no conversion is needed), they don't match. So it looks like FCPX is doing some on-the-fly conversion of sample rate.

I never thought it was the problem but it was a problem when I wanted the audio to play at the wrong speed just to figure out if there was a 44.1-48k conversion problem. 999 times outta 1000 you don't want the audio to play in the wrong speed though so it's a good thing!

"But when I add the 44.1k file that just has a 48k header (tricking FCPX so it thinks that no conversion is needed)..."

How are you changing only the header of the file?

Hi Dmitri,

Okay, I may not have explained this very accurately. Of course FCP X conforms the sample rate, otherwise you would not be able to use a 44.1 clip in a 48 KHz project at all. But conforming the sample rate does not do anything to the speed or the length of the audio clip. If your audio clip is shorter (plays faster) than your camera recording it will still be shorter (play faster) when you drop it into an FCP X timeline. That's what I meant with: FCP X does not do anything to it.

The problem is that the audio you have recorded on set does not match with the file they have sent you, period. So that's what you should be concentrating on. Either they have sent you the wrong file, no problem. Or the file did not play back correctly when you did the recording and then the only thing you can do is try and match up your recording with the file or vice-versa. If the two have different speeds you will have to correct the speed of one or the other if you want to match them up, there are no magic tricks.

- Ronny

OK, open both in QT Player. What are the duration? Different? Then you'll simply have to adjust the duration of one. I'd work on the audio file, myself, in LPX. I find it retimes audio with better quality and accuracy than FCPX.

Ronny's answer is correct.

I'll throw another twist in there. What if she recorded her music to her MP3 player off of a cassette or something like that? You would probably never know and go crazy trying to figure it out from a file-based point of view (as you are doing) when it's something else entirely. This has happened to me more than once.

I would lay both audio tracks against each other in FCP X with waveforms up full, trim the front end of both so they start at exactly the same time and then see where they end relative to each other. A simple retime to match up the end of the audio may be all you need and would take a matter of minutes.

I have done that more than once also because audio against picture can drift depending on what settings the recording devices have and I'm not convinced that you get the same lock in low-end digital equipment that you should get with pro equipment.

ronny courtens wrote: The problem is that the audio you have recorded on set does not match with the file they have sent you, period.

I never thought otherwise, Ronny!
But I initially thought that the fault of the file played on set could have been because of some error playing a 44.1 file at 48 speed or the other way around. And I thought that if I could get FCPX to play it at wrong speed, if they then matched up, I would know if that was the issue.
By creating a 44.1k file with a 48k header in Digital Performer, I could trick FCP to think it didn't need to comform the file. That showed me that the difference of speed when played wrongly was greater than the one I'm seeing. So I can now rule out that that was the problem to begin with. Mission accomplished. That was all I wanted to do, I why I wanted FCP not to comform the sample rate.

The weird thing is, she used a song from a well known artist. It seems weird that they would release a song in different versions, one being only a tiny tiny bit longer than the other. Which is why I'm still sort of suspecting that it was played at the wrong speed. But that baffles me, how could a digital device play a digital file in the wrong speed? Faulty internal clock of the device?

I've tried retiming the song from within FCPX and although I can get them to the same length, the beats within the track then don't really sync up. Which is a problem as there's dancing to the beats in the footage.

I will try to get the audio into Digital Performer or LPX, where I have more control and see what I can do.

Audacity can do a good job at that, too.

Don't know Audacity but I own Digital Performer and Logic. I used to have a music studio for 10 years so I know a thing or two about audio editing

Digital Performer used to be my main app, bought my license in 2000, I think. I got Logic at 7.2 (because at that point DP didn't work on OSX) but never really liked it much until Logic Pro X came out at which point I switched to LPX for song writing. Still prefer Digital Performer for editing over LPX though.

Hi Dimitri,
Having different versions of the same song is not that unusual. While mastering, different versions are produced for intended delivery; CD, radio, video versions, some engineers will slightly speed up song for a little pop, not to mention re-master, so maybe that is it, but if the dancer says it was the only version she has (used) then most likely not the problem. You'd think it would line up. Location reflections/reverb??? Weird.

One potential solution is to import both camera recording and the dancer's music file into LogicProX. Select the camera track to be the master track for dance/beat sync. Enable FlexTime and set the music file to conform to the camera file timing. Should line up, but you may need to adjust some beats in the track editor. Not that hard.

Slightly off topic, but I have always wondered why Apple limits GarageBand to 44.1 when it is used by lots of folks for music recording for both iMovie and FCPX? 48k is built in so why not just enable it? Just a pet peeve of mine.

Good luck,
Hope this helps, Greg

BenB wrote: "But when I add the 44.1k file that just has a 48k header (tricking FCPX so it thinks that no conversion is needed)..."
How are you changing only the header of the file?

In Digital Performer when you convert a file you have a check box that gives you the option to "Only change the files recognized sample rate but do not process the file's audio".

Oh yes, that. Always process the file for sure.