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Terrible Sync Drift – BWF Metadata set to 25FP S- Need FIX
I’m editing a feature project in FCP 6.0.4 using Red Footage that was shot at 24. I’m using the ‘M’ proxy files as my video and the audio files are bwf (broadcast wave files)
The camera team used an old school slate, so I’m syncing with inpoints.There is no sync drift with the first 4 days of my footage. Even with takes that are 8 minutes long.
The rest of my footage drifts out of sync at a rate of about a frame every minute.At first I couldn’t understand what the difference was since in FCP item properties for the files were all at 24bit/48khz.
But then when I downloaded a BWF reader and looked at the different files I noticed something alarming:The files that work well have this info in the XML data:
< NOTE >< /NOTE > < SPEED > < TIMECODE_FLAG >NDF< /TIMECODE_FLAG > < TIMECODE_RATE >24/1< /TIMECODE_RATE > < /SPEED > < TRACK_LIST > < TRACK_COUNT >1 < /TRACK_COUNT >
The files that are problematic have this info in the XML data:
< NOTE > < MASTER_SPEED >25/1< /MASTER_SPEED > < CURRENT_SPEED > 25/1 < /CURRENT_SPEED > < TIMECODE_RATE >25/1< /TIMECODE_RATE > < TIMECODE_FLAG >NDF< /TIMECODE_FLAG > < /SPEED > < TRACK_LIST > < TRACK_COUNT >2< /TRACK_COUNT > < TRACK >
The orginator on the working files is: Sound Dev: 744T S#460305081003
The originator on the problem files is the: Fostex FR-2LE.So a different sound recorder came on and recorded things differently. We went from 24fps which works great to 25fps which is way off.
Now is there a way to fix this??
Ive tried slowing down AND speeding up the sound by 4.166% and that doesnt work.
I’ve tried converting to .aiff, thinking it would strip away the date, that doesn’t work.
I’ve tried changing the sequence presets and capture presets (long shot). Nothing.This is killing me, I really need some help.
Does anyone know of someone with lots of experience with BWFs and FCP?
thanks all,
jonathan
p.s. tell me if you guys need anymore info.
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15 Replies
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Firstly a drift of a frame per minute sounds like .1% so 4% up or down is way off the mark.
Even if the metadata is flagged for 25, then it still is 48Khz. Is your timeline 23.98 or 24? My guess is that the speed drift is more likely the difference between 23.98 and true 24.
Try a .1% slow down of the 25 fps files and see if they go back into sync.
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Delete the ‘bad’ bwfs out of your project. Reset your easy setup for 24 (is it really 24 or is it 23.98?) Whatever it is, make a new sequence at the proper frame rate. Quit FCP then reopen FCP and reimport your BWFs.
Jeremy
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Goddamn!
I could have sworn I had already tried that. I guess I must have sped it up by .1% instead of slowing it down.
Sequence settings say my editing timebase is 24 not 23.98.
That totally works. So that means audio was recorded at 23.98 and by slowing it down .1% i’m conforming it to true 24? Is this the most efficient way to correct this problem? Just slow down all the audio by .1%?
Thank you so much for your help.
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Audio is audio. Adding timecode really doesn’t change its actual timing which is locked by crystal sync to the sample rate. Timecode is simply add on data.
As to why the original files sync and not the Fostex ones, I can only hazard a guess that something else also changed on the shoot and the camera was changed from 24 to 23.98 . The drift rate is consistent with that scenario.
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I agree with you, but in the case with BWF files will get tagged with a frame rate by FCP (as evidenced by those XML files posted), and with FCP it gets tagged with whatever frame rate your project is in when it was started. Strange but true. If you put FCP in the frame rate you need, or even start a new project and make a timeline with the frame rate you need, close, then open that project, you can then copy and paste it into your orig. project.
https://forums.creativecow.net/thread/8/1006830
https://forums.creativecow.net/thread/8/1006845
https://forums.creativecow.net/readpost/8/1008242
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I’m a little confused about what you said. My timeline is in the frame rate that I need for the video (24 not 23.98…in the editing timebase section of the timeline properties it says 24. It would say 23.98 if it meant that right? By “24” it doesn’t mean “24P” right?).
Others have been saying “Put FCP in the framerate that you need” but I’m confused about this. I think you mean in the easy setup which then changes both the capture presets and the sequence presets?
In those I can’t find any true 24 frame settings. Everything that says 720p24 is all 23.98.Or do I need to change my settings to 23.98 to accommodate the audio?
I will check out the strings you posted, but I thought I might throw out those questions first since itll take me a while to get through all them.
thanks a lot for your help, jeremy and michael.
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[Jonathan Rotberg] “(24 not 23.98…in the editing timebase section of the timeline properties it says 24. It would say 23.98 if it meant that right? By “24” it doesn’t mean “24P” right?). “
It all depends on how the video was shot and 24p can mean both frame rates. They could have shot 24 or 23.98 (which is really 23.976). For ease of use, I’d bet on 23.98 (which also might account for your difference in speed). You will have to check with the DP or DIT on that detail.
[Jonathan Rotberg] “I think you mean in the easy setup which then changes both the capture presets and the sequence presets? “
Yep. Easiest way is to open a brand new project and select the easy setup you need and then make a new sequence and delete the other sequence out of there. Save that project, then Quit FCP and reopen that same project. Import your BWF. Then open your original project and then copy and paste your newly imported BWFs into that project.
As far as those other threads, you will have to weed through them a bit to get to the heart of the issue.
Jeremy
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The thing is that its RED footage. ITs full stream raw files that are capture at a frame of true 24 frames per second. Like film.
I’ll work on this and get back to you.
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[Jonathan Rotberg] “The thing is that its RED footage. ITs full stream raw files that are capture at a frame of true 24 frames per second. Like film.”
Not necessairly. Red can shoot 23.98 which make sense as it fits better in to legacy systems (namely monitors and tape based layoff/later acquisition). You need to figure this out or ask the right person who was at the shoot.
As far as a preset, you need to change your seqeunce from 23.98 to 24 or vice versa then close and reopen FCP, then reimport BWFs. Just try it. Please?
Jeremy
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Ill definitely try it. I actually deleted that part of my post after I posted it since I realized something I had been doing wrong.
Thanks so much for your help, I’ll let you know soon.
Actually, before I get to this. I have a quesiton. I’ve already merged a TON of clips in my project. Would it be possible to change the settings. Close FCP. Open a new project, then open the old project and drag those merged clips into the new project? Or will that not change the “tagging” on the audio files that are part of the merged clip?
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