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Downconvert 60p to ntsc - remain progressive?

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Bob Pierce
Downconvert 60p to ntsc - remain progressive?
on Feb 19, 2008 at 11:05:16 pm

I have a client who's obsessed with everything being progressive. We have a project that I've edited in DVCPRO HD 720p60. Now I need to deliver an NTSC downconverted master for the client and he's asking if it will still be progressive on the SD version.

Now, maybe I'm thinking too much here (hardly ever the case) but, if the kona has 60 progressive frames to play with, does it take each of the 60 frames and allocate them to each field of the ntsc downconvert? If that's the case, then we're back to interlacing and all the artifacts that come with it. Does this mean we should have done the project at 30p?

Which brings up a 2nd question - the kona lhe software doesn't come with a FCP preset for 720 30p. Is there any reason why I couldn't use the kona to do 30p?

Or am I thinking too much?

Thanks!
Bob



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walter biscardi
Re: Downconvert 60p to ntsc - remain progressive?
on Feb 20, 2008 at 12:37:14 pm

SD is still an interlaced world in NTSC so yes, the project will be interlaced when you downconvert it. 720x486 interlaced for uncompressed SD and 720x480 interlaced for DV/DVDCAM.

Walter Biscardi, Jr.
Biscardi Creative Media
HD and SD Production for Broadcast and Independent Productions.

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Jeremy Garchow
Re: Downconvert 60p to ntsc - remain progressive?
on Feb 20, 2008 at 6:06:19 pm

[Bob Pierce] "Or am I thinking too much? "

You are thinking exaclty right. Each 60p frame gets mapped to a field. So your 59.94p sequence will become 29.97i with each i field being a segmented p frame. Now, if you shot 30p (which is essentially 30p x 2 which means your 60p playout will be a series of 2:2 pulldown frames) the frame doubling will be mapped to a "progressive" 30p NTSC sequence. The same works for 24p. 24p over 60p HD will turn into 24p with interlaced 3:2 pulldown in NTSC.


[Bob Pierce] "the kona lhe software doesn't come with a FCP preset for 720 30p."

No, it does not, but you could easily make one and it most definitely supports a Panasonic 720p30 workflow.

Jeremy


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Bob Pierce
Re: Downconvert 60p to ntsc - remain progressive?
on Feb 21, 2008 at 7:30:05 pm

Thanks guys. This progressive frams via ntsc thing is confusing. Anyway, I'm still not sure how you get 30p out of the Kona. The control panel doesn't have a setting for 720 30p. If I put a 30p clip into a 30p sequence in FC, it doesn't play out of the kona.
Thanks,
Bob

Mac Pro 2.66 8GB memory
Mac Book Pro 2.33 Duo
FC Studio
Kona Lhe


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Jeremy Garchow
Re: Downconvert 60p to ntsc - remain progressive?
on Feb 21, 2008 at 7:42:10 pm

You don't get 30p directly out. You get 60p. If you shoot and edit in 30pN you get a 2:2 pulldown cadence. Does that make sense to you?



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Christopher S. Johnson
Re: Downconvert 60p to ntsc - remain progressive?
on Feb 29, 2008 at 11:55:09 pm

Try using Compressor to downconvert the 720p 60 file and choose the Progressive setting on the field handling. This might make a beautiful 30p NTSC. Just an educated guess.

-Christopher



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