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


 
 
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Old June 10th, 2006, 09:19 AM   #106
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Wayne,

Email me, hmcknight@mac.com, about an HD10. I may be able to sell it (it's a lease that I'm paying off this month), depending on several factors with the leasing company.

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Old June 10th, 2006, 10:26 AM   #107
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There's a HD1 on eBay for $412, bidding. Seller still has box, juding by the photo they posted, not that this means anything of course..
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Old June 10th, 2006, 10:55 AM   #108
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Thanks guys, I had pretty much given up on that idea (my post in the classifieds forums didn't attract anything) and the H264 cameras are nearly here, the Samsung in August, the AVCHD, I don't know. So I am only looking as a cheap fill in camera. I have even been thinking of that $799 Sanyo HD1 (posting about a possible solution to the macro orientation bug over there).

So I will try the email now, Keith.

Graham, thanks, $412 would be great, but I am in need of sleep, so I'll have to check it latter. I did look at ebay previously, but the cameras went for a lot more than that by the time the auction finished.
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Old June 10th, 2006, 11:28 PM   #109
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Hey Leo, good to hear your back in action. In your soon to be extended tinkering if you ever come accross a variable for any of the presets, that would be great. For example the "Sports" preset sets the shutter to 1/250th and up. If this default could be changed to the far more usefull 1/60th and up, it would become thew single most usefull feature on the cam. Couple this with EE reduction and these used HD1's would become an amazing bargin.
Keep in touch and good luck.
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Old June 11th, 2006, 01:11 AM   #110
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Don't forget low light gain, and manual functions (especially locking the shutter down to 30/60fps).
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Old June 11th, 2006, 03:47 AM   #111
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Wayne, Ken, I will definitely try to find anything of interest. I have here default and AGC low light limits but, obviously, this needs controlled experiments. I also have few sound parameters but I haven't looked at them closely enough. Looks like they are low and high-pass filters, gain and audio AGC timing.

I agree that tweaking one of the [unused] presets is an easy way to get some manual control over exposure. I will look at it more closely.
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Old June 11th, 2006, 09:25 AM   #112
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Thanks for everybody.

As I understand, there is virtually no gain in HD mode (that famous 36 horror lux rating, as deadly as no 25fps support). This is due to noise problems with the design, which I always thought was not as good as what was needed. But, for run and gun, footage with noise is better then no footage at all.

The sensor has likely been greatly improved since it was released, so this might prove to be better then expected on some cameras.

Negative gain to extend exposure latitude is also another trick.
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Old June 11th, 2006, 12:21 PM   #113
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As long as you can controll light with variable polarizer's (ND's) or ND filters themselves, the cam always reverts to 1/30th in HD mode. At times you can finesse it to 1/60th and maintain an exposure lock, but it is tricky. If I knew I could just flick on the sports "preset" at get a 1/60th lock and then was free to lock exposure, it would save so much time and effort. One would still need to apply filters if needed to prevent it from climbing higher then 1/60th (or the old 1/250th) if there is too much light comming in. But a least you know it would never drop down to 1/30th.

I personally do not think a gain boost is of much use. In low light the cam is far too noisy for it to be much use. Lowering the shutter and leaving it in auto exposure as well as shooting in the SD HDV mode are far better options. (The SD mode looks almost every bit as good as the HD mode except for medium to long shots where you want background detail. It intercuts seemlessly with HD footage)
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Old June 14th, 2006, 03:12 AM   #114
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True 24fps/25fps on this camera.

Yes, it is totally possible to shoot 25p or even 24p, on this camera.

I was thinking of an old idea I had for fitting 25p in a 30p stream, for a universal camera footage. I contemplated on how using this technique you could do 25p on this camera, but using a external shutter working at 50th of a second, moving the timing around (smooth, but slight variations) so that 25 frames would fall in 25 of the thirty frames (I know you guys are interested in 24fps, but it applies the same). As there is nothing to record in the other five frames, they get marked as blanks and hopefully that extra bandwidth is freed up for the other 25 frames.

This works because a 1/50th a second shutter can be moved around inside a 1/30th a second frame. We move the frame so it gradually goes up against the hard edge of the beginning of the frame to be skipped, and frame after at the hard edge of the previous frame. This reduces the jump across the skipped frame. The camera shutter has to be 30th a second so the sensor is nearly always on, which might increase dark current noise. It then occurred to me, hey if it is always on then we can simply dump the 1/50th shutter image the sensor at anytime, treating the camera frames as a continuous storage device. Some 1/25th of a second images will be split across two 1/30th a second frames, but this can be joined together by software and the blanks removed. There might be a problem of a lag in between the 1/30th second frames (not true 1/30th a second) or variation in brightness because of readout, but adjusting the external shutter slightly to avoid this should eliminate it. the is adjustment, if at all required, would probably be much less then then the adjustment needed in the first and you might be hard pressed to notice it even if you were looking for it. With the first scheme, you would probably notice it, if you were looking for it, but even fi you did it would be so subtle as not to concern you anyway.

The external shutter always does 1/50th/s stopping variation in light response in the sensor as the frame period changes. You might be able to do this electrically by hacking the camera, but shutters for movie cameras start at over $100. If you can replace the lens with an SLR lens through a condenser, which would give you a number more stops lowlight, you could add the shutter there and a variable ND to reduce blowout from the extra brightness of the SLR lens.

Now, about that gain, yes please, with an SLR lens, like I described above, you could get true low light ability. About the noise, is it much better on a cool day compared to a hot day, then it is probably thermal noise and dark current. Removing the lens and applying a cooling method would reduce the low light noise problems.

So would anybody like to try these with their own camera (you don't have to replace the lens to do it)?
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Old June 14th, 2006, 03:14 AM   #115
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GRHD1 Service manual available on Ebay at the moment.

Re-edit: Whoops already covered.

I remember why I was posting here, I found what looks like a service manual for the HD1 going on ebay, if anybody would like one.

http://cgi.ebay.com.au/JVC-GR-HD1-GR...QQcmdZViewItem

Last edited by Wayne Morellini; June 14th, 2006 at 06:13 AM.
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Old June 14th, 2006, 06:26 AM   #116
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Out of curiosity, I know the GYDV500 is supposed to have a hidden uncompressed video port, are there any in these cameras, any hidden ports/sockets/pins at all on the boards? You guys have the schematics is there anything there?

I wonder if formatted uncompressed information can be tapped along the process path without having to go as far as Andromeda?
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Old June 14th, 2006, 06:27 AM   #117
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Quote:
Originally Posted by Graham Jones Senior
There's a HD1 on eBay for $412, bidding. Seller still has box, juding by the photo they posted, not that this means anything of course..
I looked but couldn't find anything, do you have a link Graham?
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Old June 14th, 2006, 06:48 AM   #118
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The camera produces a lot of heat inside which is designed to be dissipated by the aluminium frame (there is a heatpipe going to it from the DSP/encoder chips) - this surely drives up the dark current and noise of the CCD imager. I have some ideas around the CCD frontend and did some work in bypassing primitive one-BJT current sink JVC put for some reason at the output of the CCD before emmiter follower. No controlled tests yet but it surely did not make the situation worse.

The simplest way to shoot 24p on 30p would be to swap all crystal resonators in the camera for 20% slower ones and then play back the tape in the similar camera for normal acquisition of 30p source which is now in fact 24p timebase. All operations are controlled either directly from XTAL frequencies or via PLL controlled circuits. Shutter speed, frame rate, tape speed, drum RPMs, etc.
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Old June 14th, 2006, 07:12 AM   #119
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Quote:
Originally Posted by Wayne Morellini
Re-edit: Whoops already covered.

I remember why I was posting here, I found what looks like a service manual for the HD1 going on ebay, if anybody would like one.

http://cgi.ebay.com.au/JVC-GR-HD1-GR...QQcmdZViewItem
I've got it. It's not that useful.
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Old June 14th, 2006, 07:40 AM   #120
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You wouldn't believe I posted a more primitive form of this idea before and forgot all about it, but I now remember I posted a link to it, I thought here, so you guys could look at it, but I don't see any.

Here is the thread, and it adds a little more to the Scheme:
http://www.dvinfo.net/conf/showthrea...793#post460793



Leo,

This sounds good (if programmable even better), the trick is the compression engine works at 30fps. If the engine timing can't be changed, it might be possible to do the sensor frames at 24fps out of sync with the 30fps compression engine, similar to the shutter idea except sensor replaces external shutter, and frame buffer replaces 30 fps sensor storage. This could be done by giving it a blank frame every sixth frame from the frame buffer (either by changing buffer address, or filling with black, or inserting a fake black signal). A little more complex but more compact than external shutter

Patrick,

Is there anything to trace on there that might represent an output, or a place to tap, uncompressed video.
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