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Video and audio recorded separately and do not sync up

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Diarmuid Hayes
Video and audio recorded separately and do not sync up
on Oct 3, 2012 at 8:45:48 pm

I'm having a major syncing issue with some video and audio shot for a film, recorded separately, but which don't sync up in FCP7.


The easiest way to explain what's going on is this example:
There is a clip where the clapper board is clapped twice within a few seconds On my timeline in FCP7, when I mark the time between the two claps on the video track in is 7 seconds and 3 frames, but the time between the two claps on the audio track is 6 seconds 16 frames.

This means that the audio is extremely out of sync as time goes on.

I am working with footage that was shot on a Panasonic AG-AF101, and audio which was recorded on a Zoom H4n.

Audio: .wav file, 24-bit Integer (Little Endian), Stereo, 48.000 kHz
Video: .MTS file, H.264, 1920 × 1080, Millions
16-bit Integer (Little Endian), Stereo (L R), 48.000 kHz, FPS: 25

I have tried converting the MTS files to Apple ProRes, 25fps and 24fps, but the problem is the same.

Can anyone help to shed some light on this problem?


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Diarmuid Hayes
Re: Video and audio recorded separately and do not sync up
on Oct 3, 2012 at 10:00:32 pm

I should also add this:
When adjust the speed of the audio clip to slow down and sync up with the video. I end up having to use a different percentage for each clip.

90.33%
92.23%
etc

I'm working out some more calculations now to see if there's a pattern. This strikes me as very strange though.


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Thomas Alexander
Re: Video and audio recorded separately and do not sync up
on Oct 12, 2012 at 3:53:50 pm

Hello Hayes

First i would let you know that i am writing this message in a way that hopefully some people
that don't know or might get something out of it so i hope you understand.

I don't know how extended is your knowledge regarding time-codes and stuff but the problem you came across it is really complicated and at the same time common but long to explain it to you through this thread but i can guess some things and i hope they help.

But before we go on i would like to pull your ear and to recommend you to not record your audio separately once your camera provides you two XLR inputs. The only reason you record the sound separately is when you use a film camera and based on timecode after you will sync the video to your audio. "But sir, i wanted 24 bit depth audio for much clearer sound!!!" You used an external audio recorder and i don't see the reason besides the 24 bit audio recording is unnecessary. AG-AF100/101 records 48KHz 16 Bit audio which it is a fine quality even for Bluray disk. I use DTS and Dolby compression uses 16 bit and 24 but... 24 bit depth it doesn't mean it sounds better. You can have a fine crisp sound with 16 bit audio depth. Believe me it is more than enough unless you wanna fill up your hardrives faster than go ahead and use 24 bit. The AG-AF100 gives you +48v phantom power so you can use a condenser mic for perfect sound. Just make sure you do proper placement and keep the boom mic out of your shot but close enough so you can catch good clear and constant sound without interruptions. Monitoring your sound through headphones attached to your AG-AF100/101 would do the trick. That will prevent you to find out in post that you messed up and the dynamics and the levels of your sound are like a roller coaster.

Another solution to your problem might be that the way you import the footage on final cut can cause problems. You must backup your files from your SD card by selecting the whole structure of the files the camera creates and not by selecting only the MTS files and pasting them to your computer. By importing the whole structure that your camera has created on your SD card it gives more information to FCP regarding camera timecode setting or else SMPTE. Mr Shane Ross can say it better than i do so check out his video http://library.creativecow.net/ross_shane/tapeless-workflow_fcp-7/1

Third, i wanted to ask you what timecode settings have you set your camera. The PAL uses NDF (Non Drop Frame) and NTSC uses DF (Drop Frame.) You can adjust these settings directly on your AG-AF100.101 right into your menu.

There are digital clapper/slate boards and you can sync your timecode with your clapper board and your AG-AF100 through a cable which connects with a 2.5mm mini-jackthat your AG-AF100/101 has and it is called S/S. You choose the settings as your camera the Master and the slate board the slave. You have also the ability to connect other AG-AF's together through that mini-jack port for some crazy multi-cam shots.

Before you record make sure you have the right system frequency on your cam.

Your AG-AF100/101 has to be in 50Hz system frequency for PAL Europe
Your AG-AF100/101 has to be in 59.94Hz system frequency in America.
You must choose based on where your final media will end up.
Will they end up on DVD? Bluray? Broadcasting?

If they will end up for DVD in America you will use 59.94Hz system frequency
because your DVD will be region coded as NTSC so it is the same for broadcasting.

If they will end up for DVD in Europe than you will use 50Hz system frequency
because your DVD will be region coded as PAL and so it is the same for broadcasting in Europe.

Once you chosen your SYSTEM FREQ settings than go to
CAM MENU
TC/UB SETUP --> TCG and make sure is REC-RUN.

That will make your Timecode run whenever you pressing the record button of the camera. If it is on FREE RUN it will run even if you stop recording. That is according to anyones taste or situation.

But basically your timecode settings on your camera and your audio capture device might be different.
If you exported the sound in any other format or the device you used has SMPTE settings than you might wanna consider changing them appropriately.

I hope this helped but my question is, did the 24 bit worth all this trouble? 0_o


Hope to hear from you soon

Thomas Alexander
Lightman Films
Cyprus


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Thomas Alexander
Re: Video and audio recorded separately and do not sync up
on Oct 12, 2012 at 4:10:07 pm

Hello Hayes

First i would let you know that i am writing this message in a way that hopefully some people
that don't know or might get something out of it so i hope you understand.

I don't know how extended is your knowledge regarding time-codes and stuff but the problem you came across it is really complicated and at the same time common but long to explain it to you through this thread but i can guess some things and i hope they help.

But before we go on i would like to pull your ear and to recommend you to not record your audio separately once your camera provides you two XLR inputs. The only reason you record the sound separately is when you use a film camera and based on timecode after you will sync the video to your audio. "But sir, i wanted 24 bit depth audio for much clearer sound!!!" You used an external audio recorder and i don't see the reason besides the 24 bit audio recording is unnecessary. AG-AF100/101 records 48KHz 16 Bit audio which it is a fine quality even for Bluray disk. I use DTS and Dolby compression uses 16 bit and 24 but... 24 bit depth it doesn't mean it sounds better. You can have a fine crisp sound with 16 bit audio depth. Believe me it is more than enough unless you wanna fill up your hardrives faster than go ahead and use 24 bit. The AG-AF100 gives you +48v phantom power so you can use a condenser mic for perfect sound. Just make sure you do proper placement and keep the boom mic out of your shot but close enough so you can catch good clear and constant sound without interruptions. Monitoring your sound through headphones attached to your AG-AF100/101 would do the trick. That will prevent you to find out in post that you messed up and the dynamics and the levels of your sound are like a roller coaster.

Another solution to your problem might be that the way you import the footage on final cut can cause problems. You must backup your files from your SD card by selecting the whole structure of the files the camera creates and not by selecting only the MTS files and pasting them to your computer. By importing the whole structure that your camera has created on your SD card it gives more information to FCP regarding camera timecode setting or else SMPTE. Mr Shane Ross can say it better than i do so check out his video http://library.creativecow.net/ross_shane/tapeless-workflow_fcp-7/1

Third, i wanted to ask you what timecode settings have you set your camera. The PAL uses NDF (Non Drop Frame) and NTSC uses DF (Drop Frame.) You can adjust these settings directly on your AG-AF100.101 right into your menu.

There are digital clapper/slate boards and you can sync your timecode with your clapper board and your AG-AF100 through a cable which connects with a 2.5mm mini-jackthat your AG-AF100/101 has and it is called S/S. You choose the settings as your camera the Master and the slate board the slave. You have also the ability to connect other AG-AF's together through that mini-jack port for some crazy multi-cam shots.

Before you record make sure you have the right system frequency on your cam.

Your AG-AF100/101 has to be in 50Hz system frequency for PAL Europe
Your AG-AF100/101 has to be in 59.94Hz system frequency in America.
You must choose based on where your final media will end up.
Will they end up on DVD? Bluray? Broadcasting?

If they will end up for DVD in America you will use 59.94Hz system frequency
because your DVD will be region coded as NTSC so it is the same for broadcasting.

If they will end up for DVD in Europe than you will use 50Hz system frequency
because your DVD will be region coded as PAL and so it is the same for broadcasting in Europe.

Once you chosen your SYSTEM FREQ settings than go to
CAM MENU
TC/UB SETUP --> TCG and make sure is REC-RUN.

That will make your Timecode run whenever you pressing the record button of the camera. If it is on FREE RUN it will run even if you stop recording. That is according to anyones taste or situation.

But basically your timecode settings on your camera and your audio capture device might be different.
If you exported the sound in any other format or the device you used has SMPTE settings than you might wanna consider changing them appropriately.

If this doesn't work either than it means this.
The H.264 format doesn't contain a time code right? Neither your audio. So for the moment they match...
But once you encode it in Compressor or Media Encoder or any other application than you will export it as drop frame or non drop frame which will change the timecode. PAL or NTSC, right? Well the flaw is that after you time code your footage from H.264 to PAL or NTSC than your audio won't sync or match.
It will drift off time because you encoded the video to drop frame or Non drop frame.

I hope this helped but my question is, did the 24 bit worth all this trouble? 0_o


Hope to hear from you soon

Thomas Alexander
Lightman Films
Cyprus


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