Help synching 23.98 audio to 25 video

I'm trying to synch numerous WAV audio files to an HD ProRes file (25 fps / 1080 x 1920)

The audio file is: 24 Bit / 48 kHz / 23.98 TC

I've tried the following:

1. Importing as is.
2. Changing the video frame rate to 23.98 (using Cinema Tools)
3. Importing the audio files into Audacity and exporting as AIFF (Apple) signed 16 bit PCM.

But I'm still unable to get the files synched properly. Any suggestions would be most welcome as it's driving me crazy.

Sounds like the CTs step may have changed the speed. If you still have the source files, run it through Wave Agent to change the frame rate without altering the speed.



www.strypesinpost.com

I changed the speed of the original 25 fps video file to 23.98 to hopefully synch with the 23.976 audio to no avail. Will Wave Agent allow me to convert the audio file frame rate to 25 fps to match the video master I need to synch to?

Cinema Tools will conform the frame rate to match the frame rate you entered, changing the duration of the file.

Wave Agent rewrites the headers in the timecode track.

The sync drift can occur for a few reasons- You conformed the frame rate in Cinema Tools to 25fps, causing an approximate 4.1 percent speed up. FCP is interpreting the source file as requiring a 99.999% (1000/1001) NTSC slow down.

Make sure you have a copy of the unaltered source file. If you altered your source files, good luck to you.



www.strypesinpost.com

The video file I have is 25fps. Therefore, I had hoped I could change the audio rate to 25 fps in Cinema Tools but it only allows the import of video files.

So I thought that instead I could change the video file to 23.976 to match the audio rate, then once it was all synched, change it back to 25 fps. But it seems there's a problem with the conversion of the video file to 23.98, causing them not to synch properly.

Is 23.98 in Cinema Tools the same as 23.976, the rate the audio file was transferred at? I'm really lost with this.

You need to understand the relationship of the recording to absolute time. Frame rate is only a way of counting time. You can count a second in 25fps, or 29.97 fps, or 23.976fps. There are cases where the NLE will slow down the audio to keep time with the NTSC world (99.999% speed).



www.strypesinpost.com

Are you sure the AV files are exactly the same length time-wise? If so:


Do you have FCPX?

In FCPX create a 25p Project

? Import both the original 25p Video and the 23.976p Audio.

? Then time stretch the audio to the 23.976p length of the 25p video (zoom in to match frame accurately)

FCPX automatically compensates and shifts the pitch correctly and so far in trials perfectly (at minor speed changes).

? Export your 25p Pitch shifted movie.



Alternatively:


? Save the audio as a 23.976p movie (audio only) from FCP7 and use cinema tools to conform it to 25p.

? Open the new 25p audio only version in Quicktime Pro and remove the TC track in show properties [cmd-j]

? re-save it before bringing into FCP and lining it up with the 25p video.



For instant answers to more than one hundred common FCP questions, check out the LAFCPUG FAQ Wiki here : [www.lafcpug.org]

Thanks for the suggestions. I'm using FCP 7.0.3, so I'll try the second option.

The audio files are 24 Bit / 48 kHz / 24 Bit Integer. Can I use them as is, or do I need to convert to 16 bit for FCP? I seem to be having a problem getting FCP's audio setting the same as the files. Timelines I create seem to be 32-bit Floating Point and so need rendering.

Use them as is.

What G is saying is that if your 25p movie is 100 minutes long and if your audio was done syncing to a 24p version (of the 25p one) then your audio files should be ~ 4% longer time wise.

IF however you audio was done to the 25p version at 100mins long then you need not change the audio files at all.

Simply line them up in FCP without changing anything.



For instant answers to more than one hundred common FCP questions, check out the LAFCPUG FAQ Wiki here : [www.lafcpug.org]

Not exactly. It sounds to me like these are bwf files with embedded timecode that was recorded with the wrong framerate at 23.976 against picture acquired at 25 fps. Correct me if I am wrong.

By default, FCP will slow the audio down slightly by 1001/1000 when such clips are brought into a 25 fps timeline. Such clips will have a light green render line at the top of the clip when it is brought into the timeline. And the audio will go out of sync every few minutes.

What you need to do is to change the frame rate in the file header without changing the audio playback speed. You can use wave agent for this.

Where are you seeing 32 bit float? In the browser? FCP by default renders audio in floating point math for precision. 24 bits is fine. I work with that all the time.

Geez. Why is everyone recording dual system sound?



www.strypesinpost.com

Hey Marc can you enlighten us whether they are BWAV or just normal WAV.

G is right if - it's just the TC track standing in your way then it shouldn't be too much trouble.

Couldn't see the link above for Wave Agent so here it is: [www.sounddevices.com]


Its a free download in return for your contact details (as is becoming the norm).



For instant answers to more than one hundred common FCP questions, check out the LAFCPUG FAQ Wiki here : [www.lafcpug.org]

The files have the .WAV extension. They may I'm told be 23.98 Psf? They were transferred from the feature film's original track via a Pro Tools session. The folder name is:

TITLE_Reels_1_10_Eng_DME_NDF

and in the folder:

TITLE_Reel_No_Eng_COMP_NDF.wav (dialog, music & effects tracks combined)
TITLE_Reel_No_ENG_DX_NDF.wav
TITLE_Reel_No_Fx_DX_NDF.wav
TITLE_Reel_No_Mx_NDF.wav

all the way down to:

T01_1kTone.wav
T01_2kTone.wav
T01_3kTone.wav
T01_4kTone.wav

Then there's a sessions File Backups folder: All files in this have the .PTF extension.

There's also a WaveCache.wfm file.

Basically the company that did the transfer were under the impression it was synching to a 23.976 HD master, but the master was transferred in Europe at 25fps which for some reason seems the standard for HD (I think its a TV requirement). I need to create a 25fps master for the DVD release, whilst another company will be given my HD master and speed correct for the Blu-ray authoring.

OK, I've opened one of the files up in Wave Agent and it doesn't state a Frame Rate. I saved a file to 25 ND and imported into FCP and sadly the synch is still not lining up.

I'm told by the lab that they are broadcast wave files. He said there are Pro Tools and BWF files. I'm afraid I have no idea what I'm going to do - I need the job done by today.

for a quick fix just adjust the speed of the sound in FCP

i do this in the timeline:
find a sync point at the beginning and at the end of a clip of decent duration

maybe you have a slate at the head, and some obvious sync point at the end,
get the slate in sync, blade pic & sound on the slate.

slip the audio to get the end-most sync-point lined up
blade pic & sound at that point

mark in & out around the picture clip
double click the audio into the viewer,
and F11 to do a fit-to-fill edit.

see what the speed of the audio clip is, and use that speed on your other audio clips.

good luck,
nick

Alternatively, export as self contained QuickTime, conform it to 23.976 in CT (visuals only), then merge video and audio in 24p sequence, export QT movie and conform it in Compressor.



www.strypesinpost.com

Thanks for the feedback and your continued patience guys. I've now spent a day and a half trying to get the audio in synch with no luck. I tried importing onto a FCP timeline then exporting and conforming to 25fps in Cinema Tools but no luck.

I'm convinced the problem has something to do with the initial FCP timeline setting I'm using for the WAV files for export to Cinema Tools.

I've tried numerous timeline settings to avoid getting the green render line, and although I'm told the files were all transferred at the equivalent film rate of 23.976 I get a the render line using this Edit Timebase timeline setting. I don't get a render line on 24 or 25 which is strange. I've tried exporting these options to QT then changing the Frame rate in Cinema Tools to 25fps but again there is no synch.

I'm told the files are NDF Broadcast Wave File format. Does this make any difference?

I should also add that I even tried re-timing the 25fps file to 23.98 in Cinema Tools and still couldn't match it to the 23.976 WAV files. Strange eh?

Nick Meyers Wrote:
-------------------------------------------------------
> for a quick fix just adjust the speed of the sound
> in FCP
>
> i do this in the timeline:
> find a sync point at the beginning and at the end
> of a clip of decent duration


Sadly I'm working on an old feature film from the 70s. Telecine of the movie done in Rome, audio transferred in Hollywood. So no slates, I'm having to synch purely by eye.

>> of a clip of decent duration
> Sadly I'm working on an old feature film from the 70s. Telecine of the movie done in Rome, audio transferred in Hollywood.
> So no slates, I'm having to synch purely by eye.

There is still no difference in the principle. It just means you don't have neat intentional sync points. But for every piece you still need to mark two sync points (any transient will work, or at least get you to within five frames of sync) at beginning and end to make sure there's no drift.


www.derekmok.com

I've done as you suggested and the synch difference is around 100.18%. However, I'm wary of doing this for the whole movie as it still doesn't look entirely accurate for all of the dialogue scenes - and on top of this, there are ten reels in all totalling 100 minutes to adjust.

I'm sitting here wondering why the files just don't synch as they should. If we could work that out it would save me a lot of time. Anyone?

Quote

I'm told the files are NDF Broadcast Wave File format. Does this make any difference?

No NDF is non-drop frame - no progressive format is Drop-frame and Drop frame is NTSC only not Film or PAL or 25fps HD.


I have a horrible thought that the company might have transferred the film wrong.

Try true 24p

Conform the Video from 25 to 24 then test the sync.

If it works then export the final 24p master and make a 23.976p and 25p version from that.



For instant answers to more than one hundred common FCP questions, check out the LAFCPUG FAQ Wiki here : [www.lafcpug.org]

24 vs 25 would give you a speed difference of around 4%,

100.18% looks a little more like 23.98 vs 24,
but i work in PAL territories, so woold only be guessing as to to do about that.

i think this was mentioned above, but sequence preset determines audio TC on import of audio

did you set your FCP sequnce preset to 23.98 and import the audio?
did you set it to 24 and import the audio?

i'll take a small bet and say you didn't,
because while the FCP sequence presets are labelled 24p, they are really 23.98.
you have to create a NEW sequence preset at true 24,
set that as your sequence preset,
then import the audio.


fingers crossed,
nick

Thanks for all your help with this guys, but I managed to fix the problem with the help of a tech guy from the lab in Hollywood that supplied the audio files.

Quote

Step 1: Spot the Audio onto the Timeline.

Step 2: Right Click on the Audio and Select "Change Speed"

Step 3: Enter 104.271 into the Rate Box (this is the 4.271% NTSC to PAL speed increase), and click OK.

Step 4: Audio has been varisped