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Importing sound into 23.976??

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Juan Juig
Importing sound into 23.976??
on Aug 19, 2016 at 11:30:08 am

Hello,

since we always work by the standards on our academy I have never faced this issue before. Normally we always shoot in 25fps. But now I received some 23.976 fps files that have to be synched and I am not sure whether this might be the problem because of the 23.976 project settings and because video footage is 23.976.

Will there be no problems synching video and audio or is this a problem? Do I need to convert the audio or choose some special setting when importing into Avid?


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Juan Juig
Re: Importing sound into 23.976??
on Aug 19, 2016 at 11:32:11 am

I must also add that the sample rate of the audio is 44.1 kHz.


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Michael Phillips
Re: Importing sound into 23.976??
on Aug 19, 2016 at 12:46:34 pm

Importing the 44.1 audio will get converted to 48kHz (project settings upon import), but will not introduce any shift in duration or sync.

If the audio was recorded at 44.1 during production with 23.976 picture, and you are working in a 23.976 project, then "time" will stay the same, and sync is maintained.

Ideally you don't want to record 44.1 and most sound folks try to avoid any kind of sample rate conversion. But if this is just dialogue, you will be fine. As a point of reference, any music being imported from CD is also 44.1.

Michael


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Juan Juig
Re: Importing sound into 23.976??
on Aug 19, 2016 at 3:47:11 pm

The sample rate isn't the main issue here. I most certeanly realise that 44.1 is not by chance a way to go when recording audio. But the boom operator was not experienced, neither was the camera guy. The footage was supposed to be 25p, while it is 23.976 and the sound is by default recorded to be synched with the 25p footage.

So my question is whether there will be problems synching these twoo and how I can resolve this issue.

Could you please explain that to me? Nevertheless thank you mister Phillips for you response. You often respond to my posts and I really appreciate your time.


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Michael Phillips
Re: Importing sound into 23.976??
on Aug 20, 2016 at 1:37:00 am

Audio does not have a frame rate. It has samples. Timecode is calculated as an offset from midnight (0 samples). When you import 44.1 it will become 48kHz, but duration will remain the same.

What is important for sync is what the frame rate was on the video when recording audio (44.1/48kHz) as that is what is in sync. For example, I can have one camera recording 24, another 25, and another 29.97 while recording audio at 44.1/48kHz. If I import each video into its own matching project and import the 44.1/48kHz file, they will all be in sync.

So your first step it to create a 23.976 project, import video and audio (44.1 converted to 48kHz). Sync.
Open bin with .sync clips in your 25fps project. MC will add a mix and match so you will see a repeat frame every ~24 frames. I have not tried this on .sync (subclips) ,but you might be able to change the play rate of both VA in source settings playback tab. Change it to :project."

If not, then you need to make new source master clips. I would reccommend exporting OP1a with a finishing quality codec (DNxHD 120 or higher). Then link to that in your 25fps project and change playback rate to project rate.


Michael


Michael


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