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General HD (720 / 1080) Acquisition
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Old September 19th, 2004, 09:01 AM   #1
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1080/60i to 720/24p conversion

We all know about magic bullet, etc. Should it not be possible to take a 1080/60i clip from the FX1, and convert it to 1080/24p with inverse telecine?

Now there would be some interlacing artifacts if the frames were simply constructed straight, so a small amount of gaussian blur and a down-rez to 720p ought to more than make up for that.

So shouldn't it be possible to get awesome 720/24p footage out of this thing in post?

Also does anyone know about the cinemotion option? Is it similar to Canon's frame mode?
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Old September 19th, 2004, 02:40 PM   #2
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Hmmm...Wouldn't you want 1080 24p? That's better.

I'm sure you could convert it to 24p, then down-rez it to 720p.

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Old September 19th, 2004, 08:39 PM   #3
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1080/24p would of course be ideal, but when you go from 60i to 24p you lose a little bit of sharpness. My thought was that that would be made up for by downrezing to 720p.
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Old September 19th, 2004, 09:54 PM   #4
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1080/24P should be entirely possible, using something like Magic Bullet or DVFilm Maker. It won't be quite the same as if it'd been true 24P in the first place, but -- heck, it'll probably be pretty darn good!
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Old September 19th, 2004, 10:53 PM   #5
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I wonder if this is exactly what the FX1's fake 24p mode does.
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Old September 19th, 2004, 11:05 PM   #6
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I don't think it has a "fake" 24p, at least not that I've heard of.

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Old September 19th, 2004, 11:24 PM   #7
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Just a guess doesn't the DVX flag the frames it doesn't use. Because I thought it still records at 30 frames and then when you go into your editor, the editing system sees those flags and pulls those frames out.

So I'm wondering if the frame mode in the Sony will do the same. It would flag the frames and then in FCP HD (HDV) remove those frames.
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Old September 20th, 2004, 01:07 PM   #8
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It does have a "fake" 24P mode, called CineFrame 24 (and also has a "fake" 30P mode). But to be truthful, we shouldn't necessarily use "fake" to describe it until we see how well it performs. If it looks fantastic, why cripple it with the word "fake" regardless of how it accomplishes the goal?

The DVX flags the frames because it actually records 24 distinct frames per second, then adds split frames to round it out to 60 fields. The Sony works backwards from that. It can't shoot 24 frames per second, it only shoots 60 fields, so it has to somehow in-camera try to interpolate/blend 60 fields into 24 frames.

So it's actually the opposite of what the DVX does. Doesn't mean it won't look good (although I guess the potential exists for it to look awful, but we'll see). It won't be true 24P by any stretch, but programs like DVFilm's Maker software can do a pretty good job of simulating the 24P look, so maybe the Sony does a good job too...
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Old September 20th, 2004, 07:20 PM   #9
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Yeah Barry, there's pretty much one only one way (at least that I'm aware of) of taking 60i to 24p:

60i: 1A 1B 2A 2B 3A 3B 4A 4B 5A 5B

becomes

24p: 1A+1B, 2B+3A, 3B+4A, 5A+5B

OR some variation thereof,

But combining fields is problematic because the field actually occurs 1/60th of a second later than the prior field, thereby introducing combing during motion. So you have to apply some kind of blurring to eliminate the combing, reducing your resolution. My guess is that it is not reduced in resolution much worse than to 720p.

But still then it's not temporally perfect, since the temporal transition between the 1st and 2nd, and between the 3rd and 4th frames, is twice what it is between the 2nd and 3rd, and between the 4th and 5th frames. But it's little worse, if at all, than watching 24p footage telecined to 60i.

My guess is that this is what the FX1 does, and then it probably records the resulting footage in plain old 3:2 60i which Vegas hopefully will be able to ivtc for you.

If I'm right, Cinelook 24 won't be so bad. I didn't mean to disparage it when I said fake. :) It's fake like cubic zirconias are fake - still pretty good, but you won't impress the most discerning eyes.

BTW, unless I'm wrong, nothing (Magic Bullet, etc.) is really going to be any better. Well, true 24p would be.
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Old September 28th, 2004, 02:42 PM   #10
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Converting 1080i to 24P

There is some speculation that the Sony FX1 HDV camcorder will not provide true 24P, in other words the CCD will not be sampled at 24 fps.

The latest release of DVFilm Maker (2.00f) for Windows (http://dvfilm.com/maker) has a slight modification to accept frame sizes up to 1920 x 1080, so it could be used to convert 1080i to 1080-24P, or to remove either a 3:2 or 2:3:3:2 pulldown from 1080i. The clips would first have to be converted to uncompressed AVI or Quicktime.

This would yield better results than the camera's built-in 24P mode assuming that it is getting 24P by dropping frames from a 30P acquisition, or dropping fields from a 60i acquisition.
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Old September 28th, 2004, 06:58 PM   #11
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Marcus,

Thanks for posting about this, as many are interested in knowing.

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Old September 29th, 2004, 05:50 AM   #12
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My Film Effects and Standards Conversion for FCP will also deal quite happily with 1080i60 to 24p, either keeping it 1080 or converting down to 720p.

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Old September 29th, 2004, 08:56 AM   #13
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"This would yield better results than the camera's built-in 24P mode assuming that it is getting 24P by dropping frames from a 30P acquisition, or dropping fields from a 60i acquisition."

Except dropping fields is exactly how any 60i->24p conversion happens, so I think there's no reason to believe Sony's simulated 24p would be any worse than any other software's conversion. I'm not aware of any other ways of doing it.
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Old September 29th, 2004, 08:59 AM   #14
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Yes, there are much better ways of doing it. Maker uses
motion-weighted resampling methods.
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Old September 29th, 2004, 11:06 AM   #15
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Will there be an advantage to having the 50i version of the FX1 for 24P conversions. Basically, does 50i convert to 24P (via 25P) better than 60i or is there no real difference?
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