MTC to LTC to camera theory? Feedback?

[Brent_in_Sydney]

Hi all, hoping for some of the experience in the forum to chip in with some ideas here, fingers crossed!

I have a client down here in Australia who wants to shoot a music video clip with a specific effect - they want to lead singer to retain lip sync to the song and then in parts of the song where its more "busy" everything around the singer goes to a slightly faster playback speed and during the more laid back verses, it falls back to say 80% speed.

Bjork did this sort of thing for "Its all so quiet" but they achieved the effect in post Im guessing, without any ramping on location, rather careful cutting between shooting at two distinct speeds.

So the theory is this:

PT playback on location
PT can varispeed, but you cant change the amount of varispeed during playback due to the DAE...however MTC can be ramped up and down using a tempo map.

So, create a tempo map for the slowdowns and speeds ups and use elastic audio for the guide track to follow this: so the guide track plays double speed when they want to slow it down to retain sync...

So MTC generated by PT goes to a MOTU MIDItimepiece AV which can apparently convert MTC to LTC, camera then jamsyncs/locks to the LTC as it speeds up and slows down. No idea if the camera can actually do that, nor do I have info on what camera they intend to use, but as long as I can find a solution for the LTC then my part of the challenge is achieved.

Question: Is this madness?
Second question: any other way to achieve this without extra gear?
Third question: Has anyone used a MOTU MIDITimepiece AV in the less common MTC to LTC mode I'm describing?
I know lots of folks whove locked PTLE rigs to MTC generated from LTC off tape using the motu box but rarely seen it used in ther reverse fashion. Any feedback?

Hoping to bounce some ideas around - it struck me as an interesting challenge!

[apple-q]

This is done all the time on video-clip shoots. 50% playback or what ever framerate they shoot at. Normally the playback is prepared in advance since a filmcamera can not run at ANY framerate because they need to compensate for lamp flicker etc.

Of course full TC-interlock with LTC runnig half or even slower speed is little usefull. Just record a guide-track and make notes at what speed they shot which setup.

Or are you talking about live speed-ramps? So that the camera ramps up and down within one take?

[Kuba_Pietrzak]

I've been asked to prepare playbacks for music videos several times.

They told me, at what fps they are going to shoot, and I prepared playbacks (mostly using Serato P'n'T).

I've seen end result, and everything was ok.

But the decision, at what fps video was shot, took place BEFORE it started.

Kuba

[Brent_in_Sydney]

Yup - varispeed set shots are fairly commonplace over here.
What these guys want to achieve is a ramp up/down in speed DURING the take.

Any ideas on that??

[apple-q]

Originally Posted by Brent_in_Sydney

Yup - varispeed set shots are fairly commonplace over here.
What these guys want to achieve is a ramp up/down in speed DURING the take.

Any ideas on that??

What camera are they using? It could be done with an analogue (film) camera by using a camera-tacho to bi-phase converter (rosendahl is your friend) and then clock your PT rig to bi-phase. I doubt that PT/sync I/O will varispeed more than a few percent when clocked to bi-phase but you need to test this in advance. But this can only be done in an quasi-analogue interlock similar to how a film-projector is locked on a mixing stage.
Alternatively you can try to find an old Akai DD8+ or a Tascam MMR8. These machines resolve fine to bi-phase (but you need to test at what speed they stop to output audio)
I´ve done setups with an Arri LocPro using roseldahl interfaces and a DD8+ so I´m sure it can be done given that the camera outputs some kind of pilot-tone or tacho-signal. It´s definitely quite a setup and not very portable.

[therecordinghous]

i think you are confusing MTC with Midi Beat clock. MTC will not change if you change the tempo of the song.

[David W. Jones]

You don't want to drag a ProTools rig out on location for this.

Any speed changes should all be worked out in advance, so you will need to know the frame rate they will shoot, and the percentages of the speed changes, faster/slower done in post. For example... They are shooting 60i and conforming to 24p for slow-mo FX for this scene. You would then speed up your audio 2 1/2 times for playback on set.
If you do this in advance broken down by shot with a count-in for each section and burn to a CD, your artist will have time to practice lip-syncing at that speed in advance.

Good Luck!

[philper]

Straight speed changes can be accomplished in many audio editing apps, even the free Audacity. An "on-air" speed ramp like what you are talking about would have to be done ahead of time after a lot of conversation with the filmmakers using a DAW and then recording the affected audio off it for a playback dub. You cannot hook up the sync of a video camera to an audio device changing its speed (clock) with equipment normally available from rental houses--it would be a very custom rig (how much money do they have?). With normal gear you would playback the ramped track and they would shoot at a nominal frame rate (in video) and make the effect to match in post. In film there is more of a possibility of doing this on-set, but my guess is that the filmmakers would not like the lack of control and monitorability, and so would resort to separating the singer from the crowd via green screen and combining them later.

Philip Perkins

[apple-q]

He didn´t say that it´s a video camera.

[philper]

Originally Posted by apple-q

He didn´t say that it´s a video camera.

He didn't specify a shooting media so both were discussed.

thanks

Philip Perkins