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sync sound w/ off speed recording


Chris R

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I have a job coming up and

They want to shoot offspeed (slo mo) of talent and within the same take ramp the footage

to 23.98 for dialog and then ramp the footage back to slow mo after the dialog.

 

At this point i'd assume they will be shooting the take anywhere from 60fps to 100fps.

Not quite sure how this should be handled 100% yet. Should I just record at 23.98 and

they will manually have to move the audio to match picture? Or?

I assume head or tail slate will be useless.

Would love some ideas.

Thanks guys

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Actually, I think that slates will be your best bet to achieve any kind of sync. Of course that'll only sync the first frame.

they could slate mid-take just before the actor speaks, or the actor claps or rhey find some other visual/audible cue. That may get you a bit closer. The TC settings on you recorder are irrelevant in this case as it will be a non-TC workflow.

Edit: you could consider to record at 96k. That could help post to slow down your audio. Although the benefit of this is not clear. See other threads about this

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Chris: " I assume head or tail slate will be useless.  Would love some ideas. "

I would not, (assume), but this has been done before, and discussed here before...

probably means hand/ear/eye syncing in post...

but one idea would be to shoot "parallel" or "tandem" a B-cam all in sync, with TC, to put on the timeline and be a reference for the manual syncing operation...

workflow test is indicated

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probably means hand/ear/eye syncing in post...

but one idea would be to shoot "parallel" or "tandem" a B-cam all in sync, with TC, to put on the timeline and be a reference for the manual syncing operation...

 

Be warned that most digital cameras cannot capture sound at speeds other than sync-sound speeds (23.98, 24, 25, 29.97, 30). Generally, anything beyond that and the sound shuts off.

 

I think this will be a manual-sync job. I'd also suggest that they shoot a test first to make sure it can work -- and it should. I've done it myself with film speed-ramps before, though not with digital. It should "theoretically" be the same.

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Can a digital camera change frame rate (ramp) once its rolling? I think the shot is done at high speed from beginning to end and the ramping is all done in post, in which case front and end boards are useful, and shooting at 96kHz may also help.  If possible this is a discussion to have with post before shooting 

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Can a digital camera change frame rate (ramp) once its rolling? I think the shot is done at high speed from beginning to end and the ramping is all done in post, in which case front and end boards are useful, and shooting at 96kHz may also help.  If possible this is a discussion to have with post before shooting 

Ramping done in post mostly.  They can pick the spot much easier then control the ramp, either direction, and land right before or after dialog.  Been doing this a lot lately.  I try and give head and tail marks or numbers.  Depends on the cam dept cooperation.  The camera TC will be off the map.

 

PWP

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Thanks guys all extremely helpful.

Yes, ramping is to be done in post. I would have thought head slates would be useless because if they are shooting

off speed by the time they ramp it to 23.98 the original sound files are going to be way off.

As I originally thought and a few have agreed, manual is just the way it's going to have to be.

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If you aren't shooting with a time code enabled camera, an inexpensive way is to feed SMPTE to one audio track of the camera and the program audio to another. I'd also record double system (i.e. an outboard recorder with the same SMPTE feed as you are putting on the camera) in the event that post decides they want to prelap the dialog before the ramp to regular speed. If you don't have a timecode enabled recorder, you might want to look into renting one for the day.

Hope this helps!

Sent from my iPad using Tapatalk

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Thanks guys all extremely helpful. Yes, ramping is to be done in post. I would have thought head slates would be useless because if they are shooting off speed by the time they ramp it to 23.98 the original sound files are going to be way off.

 

At least if it's slated, they'll know the scene and take number, plus an arbitrary clap. Without that, they got nothin'. 

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Wish we could get some post ppl to weigh in on this...

 

Helpful to think like a fish...

 

Sound can be time-warped and pitch-adjusted by the numbers...as with any sync or pseudo-sync in this case, having a scale whence to begin doing one's math must certainly be helpful.

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I think the ramp ups should be done to a FPS that's is a multiple of 24. So 48, 96, etc. Sticks is all you can get. I believe they will do a thing called a double print sometimes, so they will do a version at 24 and a version at 48 for dailies, and let post sort out the details.

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At least if it's slated, they'll know the scene and take number, plus an arbitrary clap. Without that, they got nothin'. 

Oh I definately agree with the info on a head slate.

When I meant useless, I meant the clap.. and of course it gives them a starting point (although a very very rough point)

but obviously can't be used for the actual sync.

 

This job will be on an epic dragon mounted on a movi. Won't even be sending audio to camera because of

weight issues. Usually I throw a small lockit on cam in this setup and thats it.

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Hey guys I have one more question if you'd be so kind.

I've searched but can't seem to find what would seem to be an easy answer.

 

I'm putting a lockit (betso) on the red epic at 23.98. Camera for the most part will be shooting 23.98.

When they jump to off speed shooting, will the lockit need disconnected, or does the camera ignore

any external source when it's off speed?

 

The camera is on a movi and messing with the box could throw the balance off but if they are shooting 120fps

and the camera is being fed 23.98 I just don't want to screw that up.

 

Thanks.

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If you aren't shooting with a time code enabled camera, an inexpensive way is to feed SMPTE to one audio track of the camera and the program audio to another. I'd also record double system (i.e. an outboard recorder with the same SMPTE feed as you are putting on the camera) in the event that post decides they want to prelap the dialog before the ramp to regular speed. If you don't have a timecode enabled recorder, you might want to look into renting one for the day.

Hope this helps!

Sent from my iPad using Tapatalk

Sent from my iPhone using Tapatalk

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I'm putting a lockit (betso) on the red epic at 23.98. Camera for the most part will be shooting 23.98. When they jump to off speed shooting, will the lockit need disconnected, or does the camera ignore any external source when it's off speed?

 

The camera ignores external timecode in off-speed mode and just reverts to 00:00:00:00 for the start of the shot. Since current timecode can't handle high-speed, they just have to fake it, using frame numbers (0-5000 or whatever total number of frames they wind up with).

 

There is talk of a new variable-speed timecode system that will be subframe-based and will work with speeds up to 120fps, but it could be years before that's all finalized. My memory is that the original SMPTE timecode system was published in 1970, but we didn't get commercial products until about 1973 or so. And I never actually saw SMPTE timecode used in a video recorder until 1979!

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The camera ignores external timecode in off-speed mode and just reverts to 00:00:00:00 for the start of the shot. Since current timecode can't handle high-speed, they just have to fake it, using frame numbers (0-5000 or whatever total number of frames they wind up with).

 

There is talk of a new variable-speed timecode system that will be subframe-based and will work with speeds up to 120fps, but it could be years before that's all finalized. My memory is that the original SMPTE timecode system was published in 1970, but we didn't get commercial products until about 1973 or so. And I never actually saw SMPTE timecode used in a video recorder until 1979!

Thanks Marc for the help and info. Job went fine, but camera dept refused to even put the lockit on camera because it was on a movi.

They insisted they would jam it on a regular basis (every shut down, and every return to normal speed).

I know they repeatedly forgot throughout the day. (lovely).

 

I had a time code slate going as well so I'm sure post is going to have to use that.

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The camera ignores external timecode in off-speed mode and just reverts to 00:00:00:00 for the start of the shot. Since current timecode can't handle high-speed, they just have to fake it, using frame numbers (0-5000 or whatever total number of frames they wind up with).

 

There is talk of a new variable-speed timecode system that will be subframe-based and will work with speeds up to 120fps, but it could be years before that's all finalized. My memory is that the original SMPTE timecode system was published in 1970, but we didn't get commercial products until about 1973 or so. And I never actually saw SMPTE timecode used in a video recorder until 1979!

 

Marc,

        In 1974 we used SMPTE TC while recording on a 16 trk 3M M56 audio recorder and a video recorder on a Frank Zappa video . It was Zappa's deal, we didn't have a clue at the time. I worked at Wally Heider's.

 

                                                                                                                                            J.D.

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