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Shooting 24p but delivering the best 60i possible.


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#1 chris Beeson

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Posted 04 April 2006 - 04:44 AM

Hi guys,

Your thoughts would be gratefully received.... I need to deliver a high budget doco shot on 1080 24p to the clients in the US as a Final master at 60i. The content comprises mainly of stunning aerial shots and therefore a lot of pans and general fast movements, obviously during the 3:2 expand process the footage becomes stuttery and at times almost unwatchable.

Now, I understand that this is a standard feature film transfer process and most Americans are use to the stutter or have DVD players to correct it etc, but I feel that we can do better...

If when mastering to 60i, I was to only 3:2 the sync footage and use the aerial footage as true frame to frame without any pulldown (it runs a little faster, generally un-noticeable, but the results are flawless), would there be any major repercussions?

Would the mixture of pulldown and non pulldown footage cause problems?

Would the broadcaster (very fussy tech spec guys) blow a fuse?

Would it cause problems converting to 50i or even SD PAL?

Would home DVD players correct for pull down even on the non pull down stuff?

Would Americans even notice?


Whats your views?

And thanks for your time.
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#2 David Cox

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Posted 04 April 2006 - 05:28 PM

I can't think that you will come across any problems other than the obvious speeding up issues. Effectively, you are doing the same as mixing progressive and interlaced footage in the same cut. If someone tries to do a reverse telecine (remove 3:2 pull down) on your footage then they might end up with frames made of mismatching fields, but why would they try and do that anyway?

So if you can live with the 25% speed up, go for it I say!

For your 25FPS masters, you might consider using your process for the whole transfer, sync included. This is common to get from 24 to 25 FPS since the interpolation from 24 to 25 is even worse than from 24 to 30. Feature films shot at 24 frames per second are commonly transferred at 25 frames per second, with their sound tracks sped up by 4% to match. The sound tracks are also pitch corrected so although sped up, don't raise in pitch. Almost any sound house can do this easily.

By using this method for your PAL masters, you will avoid NTSC - PAL conversions that *might* get slightly upset with the mixed format masters. To be honest, for the cost of a sped up sound track, I would do it anyway to avoid the conversion.


David Cox
Baraka Post Production
www.baraka.co.uk
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#3 Michael Most

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Posted 05 April 2006 - 09:15 AM

If someone tries to do a reverse telecine (remove 3:2 pull down) on your footage then they might end up with frames made of mismatching fields, but why would they try and do that anyway?


"They" would try to do that to create the PAL master from the HD original. And it would not be pretty, but it would also not be tragic.

Feature films shot at 24 frames per second are commonly transferred at 25 frames per second, with their sound tracks sped up by 4% to match. The sound tracks are also pitch corrected so although sped up, don't raise in pitch. Almost any sound house can do this easily.


Television programs and almost all features that I know of are almost never pitch corrected for the PAL version. They are simply sped up, and the sound becomes whatever it becomes.
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#4 chris Beeson

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Posted 07 April 2006 - 12:56 AM

Thank you both for your help, but I guess the big question at the end of the day is... is the broadcaster likely to reject the programme for mixing pull down and non pulldown material???


thanks again

Edited by chrispy, 07 April 2006 - 12:56 AM.

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#5 Michael Most

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Posted 07 April 2006 - 08:32 AM

Thank you both for your help, but I guess the big question at the end of the day is... is the broadcaster likely to reject the programme for mixing pull down and non pulldown material???
thanks again


The only technical specs you need to adhere to are those in the delivery specifications. Those will tell you what tape format(s) they expect, i.e., Digital Betacam if SD, D5, HDCam SR, or HDCam if HD, and what to put on those formats - i.e., NTSC if Digital Betacam, 1080i/60 or 720p/60 if HD. What is in that material is irrelevant as long as it conforms to those delivery specs.

In other words, no, there would be no problem with a US broadcaster. But check those delivery specs.
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Technodolly

Ritter Battery

Broadcast Solutions Inc

Media Blackout - Custom Cables and AKS