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JVC Everio GZ-HD7 just announced at CES 2007


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#1 Troy Warr

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Posted 07 January 2007 - 12:57 PM

I posted a thread a few weeks ago about the possibility of using an industrial CMOS camera as an HD cinema device. The idea would be to use the low-cost C-mount camera tethered to a PC with framegrabber software via Ethernet, which would theoretically allow for recording 1080/24p footage, which is what I'd ideally like to capture within my budget of about $5000.

Long story short, people seemed to think this was a viable idea, but not with the particular camera that I had in mind. I have a few e-mails out to various manufacturers now but have yet to narrow down a capable camera.

Today I saw an article announcing a new camcorder from JVC to come out in a few months:

http://www.camcorder...s-HD-Everio.htm

Here are a couple of press releases on the JVC website:

http://www.jvc.com/p...em=549&pageID=1
http://www.jvc.com/p...item=544

The camera is said to record "full HD 1920 x 1080i," in a manner that, if I understand correctly, approximates the approach of the Panasonic HVX-200 by using pixel shift to achieve an effective resolution that satisfies 1080p's 1920x1080 frame size. It's an HDD camcorder, which frees JVC from miniDV tape's 25Mb/s data rate, and they've gone with a moderately higher 30Mb/s to the onboard HDD. The camera also has an HDMI port (!) which, if it works anything like Sony's implementation, would output uncompressed HD before it hits the encoding processor and is sent to the HDD. It's a consumer camcorder, but the latter press release link above mentions "manual controls that appeal to the serious videographer." It also has "a Fujinon lens used in broadcast video cameras" (?).

Given that all of these assumptions hold true and that the camera is delivered as expected, what are your opinions on a setup along these lines for independent filmmaking purposes:

- JVC Everio GZ-HD7 camera ($1799 MSRP)
- Blackmagic Intensity PCI card ($249 MSRP)
- Brevis35 HD Imaging Bundle ($1000 MSRP - assuming a suitable achromat does/will exist)
- Nikon 35mm SLR lenses (start with the 50mm f/1.4D AF Nikkor at $280, build from there)
- My current PC (should be adequate to capture/compress the inbound HDMI stream)

This seems to me to be a pretty decent system for about $3500 (probably closer to my $5000 after typical accessories). Obvious downsides are lack of portability (which I'm willing to accept) and potentially limited manual controls on the camera - we'll just have to wait and see on that end. Upsides are (potentially) uncompressed 1080p 4:2:2 HD - assuming I can really capture the pre-processor stream via HDMI as on Sony's gear - and (practically) better quality compressed footage that can ever be captured with an HDV codec.

I have no idea what frame rate the camera will record at (I'm assuming to the HDD it sends 1080/60i, but the press release mentions progressive CCDs so maybe 30p initially?), but I think I can be confident that with the Nikon 50mm f/1.4, the Brevis35 adapter (which has roughly 1 stop light loss), and the Fujinon f/1.8-1.9 on the camera, I can probably reasonably expect an effective maximum f-stop of about 2.8 - does that sound about right?

Again, I ultimately want to achieve 1080/24p if at all possible. If the camera captures 60i or 30p, what are my options for conversion? What are the drawbacks with that from shooting native 24p, which I seriously doubt the camera will offer?

Sorry for the long post, just excited here! :lol:
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#2 Thomas James

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Posted 13 January 2007 - 11:10 PM

Full HD 1080i is just a marketing gimmick because the truth of the matter is that 1080i is an interlace format which only scans 540 lines at 60 fields per second. When 2 fields are added a theoretical resolution of 1080 lines is achieved but since this would produce unbearable flicker the resolution must be softened which usually results in an image with 800 lines of resolution at best but if fast motion is introduced the resolution goes down to 400 lines. 720p because it use a superior progressive scanning technology will always have higher resolution than 1080i and in the time it takes 1080i to scan 540 lines 720p will have already scanned 720 lines and when 1080i has scanned 1080 lines 720p will have scanned 1440 lines.

1080p promises to be higher resolution than 720p but the problem is that the 1080p frames are segmented when they are converted to an interlace stream for recording and this results in a softening of picture quality to less than 1080i quality to reduce interlace flicker. The only way to exploit the full potential of 1080p is to use progressive capture and progressive recording so that a full 1080p60 stream is created even though it may carry only 24 or 30 unique frames.
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#3 Troy Warr

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Posted 15 January 2007 - 06:20 PM

Hi Thomas

Thanks for the input. I realize that the "Full HD" phrase is merely a marketing tool, but I'm surprised to hear some of the other statements that you've made here.

When 2 fields are added a theoretical resolution of 1080 lines is achieved but since this would produce unbearable flicker the resolution must be softened which usually results in an image with 800 lines of resolution at best but if fast motion is introduced the resolution goes down to 400 lines.


What are you basing this on? Keep in mind that, provided the camera is only capable of 1080/60i, I'd intend to use a de-interlacing program to apply a reverse 3:2 pulldown to simulate 24p.

720p because it use a superior progressive scanning technology will always have higher resolution than 1080i and in the time it takes 1080i to scan 540 lines 720p will have already scanned 720 lines and when 1080i has scanned 1080 lines 720p will have scanned 1440 lines.


Assuming that we're talking about 1080/60i vs. 720/30p, the more common recording formats for these resolutions, I don't believe this is true. 1080/60i will capture 2 fields of 1920x540 every 1/30 of a second (for a full 1920x1080 frame), while 720/30p will capture 1 frame of 1280x720 every 1/30 of a second. Though 1080/60i is only capturing 1 field at a time while 720/30p is capturing 1 frame at a time, the former is capturing images at twice the rate of the latter.

1080p promises to be higher resolution than 720p but the problem is that the 1080p frames are segmented when they are converted to an interlace stream for recording and this results in a softening of picture quality to less than 1080i quality to reduce interlace flicker. The only way to exploit the full potential of 1080p is to use progressive capture and progressive recording so that a full 1080p60 stream is created even though it may carry only 24 or 30 unique frames.


Again, can you point me to your source(s) for this information? Not that I necessarily doubt what you're saying here, but this is news to me. It may just be that I'm assuming some details that are different from what you intended to convey.

Basically, I'm looking for a recording solution that will ultimately leave me with 24 progressive frames per second at 1920x1080 resolution. I realize that this particular JVC camera may not work for these purposes, and that it likely just encodes progressive information from the CCD/CMOS into a 1080/60i stream, which may or may not be easily converted to useful 1080/24p frames. But, as far as I'm aware, a 1080/60p stream is not always necessary to record in 1080/30p or 1080/24p - I think that's determined by the particular camera and recording format being used. Granted, the formats in my price range are generally limited to HDV, AVCHD, and *possibly* Panasonic P2, but the latter is capable of recording true 1080/24p progressive frames, without having to embed them in a 1080/60p stream.
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#4 David Mullen ASC

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Posted 15 January 2007 - 06:59 PM

I can't get beyond the fact that it has 1/5" CCD's that are only an effective 976 x 548 pixels each...
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#5 Troy Warr

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Posted 15 January 2007 - 08:09 PM

I'm totally with you there! I'm hoping that at the very least, it will form the full 1920x1080 picture in a way that's comparable to the method used by the Panasonic AG-HVX200. Since that resolution is essentially 1/4 of a 1080i/p frame, I'd guess that it has to employ both vertical and horizontal pixel shift to reach an effective resolution sufficient for the claimed "Full HD 1920x1080i."

The 1/5" CCDs are definitely troublesome, though... no doubt that it's going to at least suffer in low light, unless JVC has somehow one-upped the competition in this regard.
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#6 Tibor Duliskovich

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Posted 23 January 2007 - 05:19 PM

The pixel shifting was discussed here: http://tinyurl.com/y83rkp.

I believe that 1080i recording has nothing to do with resampling the originally captured 1080p. It should not affect the image quality in any way, as it simply disassembles the full frame into two half frames for recording purposes (legacy issues), that is all.
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