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JVC GR-HD1U / JY-HD10U
All about the original single-CCD HDV camcorders from JVC.


 
 
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Old December 13th, 2003, 07:38 AM   #91
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I've still not seen any pictures or video from the HD10 to see how it's sharpness compared to the HD1.

More DSP power in any camera will help the picture, as well as having more pixels on the CCD than it needs for it's rated resolution.

What I don't get is why 18mbs for the MPEG2 stream on the HDV? It's on DV tape, which we know can cope with 25mbps, so why not use them all and squash some of those MPEG artifacts we're seeing? Why not record real 24p and save some more of those precious bits per second for the picture?

Also, can someone shoot some resolution charts with the HD10 and also some colour charts, so we can see truely what the colour on the camera looks like?

Graeme
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Old December 13th, 2003, 08:25 AM   #92
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I'm confident that the JVC only uses 80% of available DV tape bandwidth because they didn't have enough DSP power to generate the full 25Mbps steam. I believe JVC said that themselves.

I also believe the shortage of DSP power is the reason other manufacturers haven't pursued consumer HD cameras yet. They clearly didn't think it was possible.

When you realize the processing required to do HD and the MPixel/second read rates, you understand the decision to use 1CCD. 3CCD's at the desired resolution would be generating 100 MPixel/second of raw data. It's quite a leap to process that much data in the current size/heat/power package the JVC targeted. JVC's raw pixel rates are comparable to existing 3CCD DV cameras. It's processing requirement is greater because of the mpeg compression.

Eventually, silicon process technology will allow DSP's to provide the processing necessary and consumer 3CCD HD cameras will be possible. It remains to be seen whether engineers will take the 3CCD route or not (or how long before they do). Right now the problem is computing, not optics and CCD.
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Old December 13th, 2003, 08:57 AM   #93
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i didnt say that the camera(stills) and video camera are un related of course they use the same technology and are very related, BUT they are designed for different PURPOSES, thus excel in the area they where designed
Take this example :

a loud speaker and a microphone BOTH use the same technologies are very related yet you try using a loud speaker as a mirco phone and vise versa get the point

about the Nikon D2h it uses JFETS so whats your point?

"- Curious that the DVX at its pixel rates can't do HD. So much for the superiority of 3CCD."

do you some have an intimate knowledge of the DVX's DSP module, if JVC could use a DSP to pump out HD from a 1/3" 1CCD your saying that Pana couldnt not be able to use an DSP that is incapable to produce HD from 3CCD?


"- JVC video is garbage."
if you say so Craig thats not what i said i said Garbage in Grabage out *univeral law*

"- 3CCD cameras may eliminate the Bayer pattern, but not the color filtering. The prism has problems of its own."

so your saying the 1CCD has solved the filtering system?

"- The Nikon D100 uses an interline transfer CCD, and architecture DESIGNED for video cameras."

so why cant nikon just use an approprite DSP and record 30fps of 4K by 2k frames ?

"- There are very few aspects of imager design that restrict their use to still or video."

Oh apart from a DSP, if this is so , please please tell me why we are not recoding video with frame sizes that digital still cam produces?

"- The Nikon D2h processes in excess of 32Mpixels/second. The DVX does at most 10Mp/s per CCD and the JVC does 30Mp/s. Still cameras have no problem keeping up with video speeds."

and what does the end result? a few still frames not video, hmm...

the DVX's DSP is its bottle neck its format is now way gonna compete with HD granted, but MPEG2 to record HD content c'mon it aint good enough, i've gotta go i'll finish this later
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Old December 13th, 2003, 09:17 AM   #94
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There are 5 megapixel digital still cameras which are better than the current CineAlta, which I think is 2 megapixels, right?

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Old December 13th, 2003, 10:49 AM   #95
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Anhar,

A fundamental assertion of yours was:
Quote:
a 3CCD system is better than a 1CCD sytem period.
You dismissed analogies with digital still cameras because, as you say:
Quote:
they are designed for a different purpose
It's clear that the digital still arguments don't support your claims. Ultimately, the only difference between still and video that you (or anyone else) can come up with is the issue of high-res/low framerate versus low-res/high framerate. None if this matters when it comes to generating the best possible image in a frame. That's what it's all about for video or still. There are technical considerations (such as interline transfer CCD's, pixel rates, DSP power, etc.) which I've attempted to address. Other differences between video and still---lens zoom ratios, ergonomics, storage devices---are driven by user needs, not fundamental technical differences. It is the optimization of the entire product that differentiates video and still, not some imaginary internal technical incompatibility. It is possible for a single device to do exceptional video and still but it's unlikely that the resultant tradeoffs would make the product attractive to buyers.

3CCD and 1CCD are two different approaches to achieving color out of monochrome sensors. Each has it's strengths and weaknesses. In the JVC case, it wasn't realistic to process 100MP/s using available size, weight, and power so 1CCD was the only choice. That's not proof that 3CCD is better but it's certainly proof that 1CCD is better in this specific case. Time will tell how popular 3CCD wil be in consumer HD cameras but it is out of reach today.

I suggest again that you read JVC's discussion of how its 1CCD design works. It is my belief that 3CCD's big quality advantage comes from it's reduced dependency on antialiasing rather than the improved raw color bandwidth that's commonly believed. The greatly reduced antialiasing means that the image can be inherently sharper. I also believe that 3CCD camera manufacturers intentionally crank up saturation since it plays to the buyer's belief that 3CCD designs provide "more color". I would be happy to hear other's opinions on this. After reading the JVC 1CCD paper, everyone should understand that the JVC design produces more color bandwidth than the format can use. In practical experience, it is not color but image sharpness that has been the big issue. That does not surprise me at all.
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Old December 13th, 2003, 11:44 AM   #96
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I don't see how you think 3CCDs need more DSP power to process the info. Surely, to extra colour information from 3CCD is going to be a lot easier than from a 1 chipper where you actaully have to do a fair bit of processing.

Also, surely the greatest use of DSP power in the JVC is to produce an MPEG based data stream rather than a DV one. Inter-frame encoding taking more processing power than Intra-Frame encoding.

Graeme
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Old December 13th, 2003, 12:04 PM   #97
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You have 3 times the raw data rate with 3CCD assuming the same resolution sensors. You don't have to do the demosiac but you do have to have data paths and hardware to process three sets of data streams rather than one. I have no idea how data from 3 independent channels gets processed into a single, compressed stream, but if you discard the extra data up front there wouldn't be a color advantage. If you carry the extra data through the process you clearly have more signal processing.

In any event, I agree that the mpeg encoding is what took a lot of DSP power. It's not just DSP, though. There is size, heat and power consumption to worry about. Each CCD and its associated ADC's and data paths consumes power. I think it was power, heat, and DSP that drove the issue as much as cost.
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Old December 13th, 2003, 12:19 PM   #98
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I have a PDX10, which has 3 CCDs, each of which is >1mega pixel. It uses the extra pixels to provide a better quality image by subsampling, and proper 16x9. Also, through posts on this forum, we've found that it also has a superb digital zoom as it uses all those extra pixels for greater resolution. From this example, I don't see that the CCD's or their DSP is the issue here. It's most likely to be the MPEG 2 processing that is eating the battery and processing. MPEG2 has come a long way, but 18mbps doesn't cut it for high def.

I guess we'll only find out what the HDV format is capable of when it gets used in a professional camera, rather than the JVC.

Graeme
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Old December 13th, 2003, 12:35 PM   #99
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Don - "I would much rather shoot with a 'full-on' DVCPRO50 or 'DVCPRO100' camera with a sweet lens."

So would most anyone. But I think going from $3000 to $12,000 is a price differance keeps that keeps this option unrealistic.
Also, in regards to the wavey vertical lines you mentioned, can you refer me to an example or explain more. You are the first who has mentioned this and it has me puzzled and concerned.
Ken
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Old December 13th, 2003, 12:41 PM   #100
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I don't know how the PDX10 processes the pixels coming from its CCD's, but I doubt it carries a full 1MP from each each sensor all the way through the process. It's possible the subsampling is done "on-chip". i.e. through prgrammable circuitry that connects the CCD to the ADC. I doubt any more data is processed than necessary. These devices are light on power.

Future cameras should always be capable of better than current ones.
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Old December 13th, 2003, 04:38 PM   #101
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Both clips, up-rezzed from the camera original up to 1920 x 1080. The DVX clip is 1920 x 1080 x 24P, the JVC clip is 1920 x 1080 x 30P.

http://66.78.26.9/~fiercely/DVXvsJVC/DVX-1080.mpg

http://66.78.26.9/~fiercely/DVXvsJVC/JVC-1080.mpg
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Old December 13th, 2003, 11:45 PM   #102
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The new DVX 1080i clip looks better than the old 720p clip. Shouldn't it look worse?
Ken.
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Old December 14th, 2003, 10:54 AM   #103
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The new DXV clip looks very soft to me. It also suffers from a motion artifacting due to the scale -- you can tell the subject is moving in a lower resolution space. This is clearly more detail in the JVC footage, as I converted them both to CFHD AVIs and found the bit-rate climbed 20% for the JVC over the DVX footage -- this is a quick and dirty non-subjective experiment that messures detail.
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Old December 14th, 2003, 12:37 PM   #104
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Quote:
found the bit-rate climbed 20% for the JVC over the DVX footage
Keep in mind that the JVC was 30P, the DVX was 24P. That alone should account for the 20% increase in size.

I've got more clips finally, which I'll be posting later. I've been following this argument back and forth because I find it interesting, plus by posting the clips I pretty much started it. I think people have taken it on tangents that I never expected, which is always fascinating.

The original purpose of posting the up-rezzed clips was to see how the cameras compared at comparable resolutions (both by up-rezzing and downrezzing). But a lot of discussion veered off on color rendition, and how some people liked the DVX colors so much more, whereas others think they're super-saturated unrealistic, and that the JVC has the more accurate color rendition.

For the record, the DVX clip shows the color that was in the scene much more accurately. It was hyper-saturated, with lots of purple and blue gel light thrown in. But the argument about color is completely specious and should be put to rest: the DVX can deliver any kind of color you like. If you don't like what you're seeing, keep in mind that the DVX gives you control over detail level, chroma level, chroma phase, color temp, master pedestal, gamma curve, skin tone detail, adjustable color matrices, and the DVX100A gives you even more control. You can dial in exactly what color you want, so color rendition should never be used as an argument against the DVX, only against the JVC, since with the JVC you get what you get whether you like it or not.

After extensive use of both these cameras, and especially after discovering just what S-Spline Pro is capable of, I have come to the following extreme analogy to describe what the choice is like (to me, others will disagree):

Let's say you have two doors to choose from. Behind door number one, you will be given an expert hour-long Swedish massage by a gorgeous and talented masseuse, after which you will be handed $80,000 in universal currency that can be spent anywhere in the world.

Or, behind door number two, you will be given $100,000 in Sears gift certificates, good only in Sears stores in Kansas.

That's how I see it. Using the DVX is luxurious. Using S-Spline Pro to up-rez, you'll get about 80% of the picture that the JVC is capable of. However, you'll be able to use that picture anywhere: you can transfer to film and show it in any theater in the world, you can broadcast it on HDTV, you could use the SD signal on NTSC tv or easily convert it to PAL and have a worldwide broadcast. By comparison, using the JVC is relatively torturous - no picture controls, no true manual controls, no remote jack, no ND filters, no monitoring of HD as you record, no focus marks, and on and on. You'll end up with a picture with higher resolution, yes. But it can only be used in a very few certain areas. It cannot be transferred to film, it cannot be transferred to PAL, it can only be theatrically projected in areas that have digital projectors (probably less than 1/100 of 1% of the theaters in the world), it can only be received in its full HD glory by about 1% of the US population (those that have both HD TV's and an HD delivery system, meaning an HD tuner, HD cable service, or a DVHS deck).

A less controversial analogy would be this: the JVC is like using a 35mm Cameflex to shoot 35mm Ektachrome color reversal film. The DVX is akin to shooting Super16 Vision 2 color negative, using an Arri SRIII. It's actually a fairly accurate analogy because blowing up S16 to 35mm requires about a 3x optical magnification, about the same as SD to 720P HD. And using today's digital intermediate technology is equivalent to using S-Spline Pro. S16 negative will give you exceptional control over the image, whereas 35mm will unquestionably have higher resolution, but the Ektachrome will have much narrower latitude, etc.

To each his own, use whatever tool you prefer. For my purposes, and I'm sure for many others, the JVC's increase in resolution is just not worth the compromises, but for many of you that may not be an issue. At least by posting these clips, you now have more of a basis for comparison to base your choice on.

Once the next generation of HDV cameras arrive I expect that my position on this comparison may take a 180-degree turn. An HDV PD170 or XL2 or DV5000U should (should) smoke the DVX in all measurable ways, not just in resolution.
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Old December 14th, 2003, 01:13 PM   #105
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<<<-- Originally posted by Barry Green : Keep in mind that the JVC was 30P, the DVX was 24P. That alone should account for the 20% increase in size.
-->>>

I had already taken that into account (remember I do this for a living -- video compression technologies.) The total data size increase was 40%. Only 20% was due to increased detail in the JVC footage, the other 20% like you suggest is the different between 30p and 24p.
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