Curious about TC mysteries

[napoleao]

Hi folks,

I have some common questions about TC because I have just received my 744T.

Why use 30fps on the audio recorder when shooting 24fps film (considering a 60 seconds TV commercial)? If the pos will do the job at 29,97fps, why not to use the same TC on the recorder?

When should I use 48.048kH?

If I record audio at 30fps and a digital camera record image at 23.96fps how can I fix that in FinalCut?

Thanks!

N.

[Philip Perkins]

Hi folks,

I have some common questions about TC because I have just received my 744T.

Why use 30fps on the audio recorder when shooting 24fps film (considering a 60 seconds TV commercial)? If the pos will do the job at 29,97fps, why not to use the same TC on the recorder?

When should I use 48.048kH?

If I record audio at 30fps and a digital camera record image at 23.96fps how can I fix that in FinalCut?

Thanks!

N.

30 for 24 film: in USA telecine there is a "pulldown" of .1% done to the play speed of the film.  The traditional way of getting the audio in sync with this "pulled down" film playback is to playback audio recorded w/ 30 fps TC at 29.97

fps TC.  This goes back to the days of analog reel-to-reel audio, but it is the method that everyone knows for that sort of syncing.  If you suspect that the sync will be done in an edit system then you need to make further enquiries about how they will do that before you decide on your TC frame rate (and sample rate too).

48.048 is very useful if the film will be pulled down in telecine but they will not be syncing sound there, they will instead be doing it in an edit system.  The edit system will run its audio at 48k.  In order for your audio to sync with the video files of the pulled-down film playback, your audio has to be pulled down too.  One method of doing this is to record audio at 48.048 (.1% pulled  UP) so that when it is played in the edit system at 48k it will play as "pulled down" to match the film speed.  This is a VERY fraught choice to make anymore, and I won't do it unless specifically instructed to by post.  You gotta talk to those guys BEFORE the job...

If you are shooting with a digital camera that is rolling at 23.98, then IN GENERAL I would roll at audio at 23.98 too.  But you really have to ask what their syncing methodology will be..there are a LOT of ways to skin the cat nowadays.

Philip Perkins

[napoleao]

Hi Philip,

thanks for the answers. I will do my "homework" testing my 744 (at

many configurations) with Final Cut and ProTools. Just one more thing, is there a manual or book to study these TC procedures? Here in Brazil, I could not find anything good enough.

Cheers,

N.

[studiomprd]

" I will do my "homework" testing my 744 (at

many configurations) with Final Cut and ProTools. "

that is the most important thing: test the workflow!!

[napoleao]

Great tips. Thank you guys. If you need any help in Brazil, just email me.

napoleao-cunha@hotmail.com

Best regards,

N.

[soundtrane]

Yes, Napo, I want to get in touch with Hermeto Pascoal!

-vin

[Eric Toline]

Yes, Napo, I want to get in touch with Hermeto Pascoal!

-vin

Here you go: www.hermetopascoalealinemorena.com.br

Eric

[Marc Wielage]

I have some common questions about TC because I have just received my 744T. Why use 30fps on the audio recorder when shooting 24fps film (considering a 60 seconds TV commercial)? If the pos will do the job at 29,97fps, why not to use the same TC on the recorder?

It all depends on post. Brazil uses the PAL-M video standard, and I can't recall if they transfer film at 24fps or 23.98fps. Ask post to be sure. My gut feeling is that if the film is being shot at 24fps, then you should always use 30NDF timecode. If it's a video shoot (assuming HD), then I would expect it's at 23.98fps, so timecode should be either 29.97NDF or 23.98.

When should I use 48.048kH?

Very good explanation on Trew Audio's website:

http://www.trewaudio.com/articles/julian_daboll/

If I record audio at 30fps and a digital camera record image at 23.96fps how can I fix that in FinalCut?

You need to pull down the audio by .1% in playback. I would just pull it into Pro Tools or Logic and do a manual time-adjust and create a new sound file. If it's short takes (under 10-20 seconds), I'd just re-adjust sync by hand. You won't see drift until it hits about :30 seconds.

BTW, funny story: I just worked on a project where a producer ran into problems where on-camera video monitors were running out of sync with sound in post. He did the opposite: he sped up the monitor footage to match the sound. This got them back in sync, but created all kinds of video artifacts due to the non-standard frame rates. Tweaking sound speed is much cleaner than changing video speeds. (Of course, getting both right to begin with is best of all.)

--Marc W.

[napoleao]

Hi Marc,

Thanks for the anwsers and the link. Do you always do a "pull down" in Pro tools to deliver your audio to post? When I record sound to 24fps film, I have never did that, just send a DVD to pos (48kH, 30NDF) and a detailed sound report...Am I being amateur? Talking about videos shoots, I am using 23.98fps with RED with no problems too. I jam from 744 to my Lockit and hang it in the camera, repeating the procedure 4 times a day, just to be sure. BTW, I am about to buy a TC Slate and want to compare Denecke and Ambiente. Some tip for me?

N.

[Marc Wielage]

Do you always do a "pull down" in Pro tools to deliver your audio to post? When I record sound to 24fps film, I have never did that, just send a DVD to pos (48kH, 30NDF) and a detailed sound report...Am I being amateur? Talking about videos shoots, I am using 23.98fps with RED with no problems too.

The only time a pull-down should be required is when shooting 24fps film and posting in an NTSC (or 60Hz) country. If you're shooting 23.98 HD video, then in effect it's "already" been pulled-down, so you would run timecode at 29.97 or 23.98, your choice.

Ideally, in a perfect world, I think it makes sense to provide the exact same matching timecode on the camera for the sound. Of course, this only works if you have updated slates, generators, and recorders with 23.98 capability. If your current set-up for Red is working correctly, then it seems to me you're doing it right.

Note that all audio pull-down for film should be done by post as part of the post process. This is something the mixer shouldn't even have to be concerned with. The danger is, don't use 23.98 or 29.97 timecode with 24fps film. The one possible exception might be if the camera is already rolling at 23.98, but this is extremely rare in my experience.

--Marc W.