Uncompressed signal out .. what does it mean ?

D-VHS is MPEG2, Yes. The 28Mbps datarate is 50% higher than 19Mbps HDV format.
I have no idea what this means in terms of picture quality; it's anyone's guess.

You bring up an interesting point in W-VHS.. wasn't thing (EDIT:that) an analog HD format or something?
 
To answer the redindian's original question, "what is an uncompressed signal out"
---------------------

1) The same thing as the analog composite or S-video output on a MiniDV camera,
except on the small HD camera it's three composite connections for a component signal.

2) The same thing as the three analog composite connectors on the back of a dvd player
with component outputs, except they are HD-ized in a Hi-Def camera and not SD.

brian wells
 
D-VHS is the same thing as HDV. So recording to D-VHS would defeat the whole point of why you wanted to go uncompressed in the first place.

Don't know anything about W-VHS. It was 1080i-only, wasn't it? If so you'd be crossconverting the 720p output of the camera to 1080i, then recording that on the W-VHS deck... but I have no idea what sort of recording format or compression W-VHS uses...
 
That's the problem. It's hard to find info on it. Best thing would be somebody who has a contact in JVC ask for info.
 
The idea of using the component output of any one of the current crop of HDV cameras has caught my eye for green screen studio work, as I have a bunch of this to do before the new Panny comes out.

Rather than assuming it the component output from these cameras would have to be captured uncompressed, with all the bandwidth overhead that implies, surely there must be a vaguely affordable way to convert the analog component signal on site to DVCPro50 -- and either record to tape in that format, or direct to disk in a laptop or even a desktop computer.

For example, at the high end, using Panasonic's AJ-SD93 with the optional component input module would do this, and also allow (as I understand it) direct DVCPro50 firewire output in addition to rolling tape. But it's an expensive solution -- close to $8k for the deck and the deck's optional card that's needed to pull this off. On the other hand, this deck would also be a useful way to record long runs from Panny's new camera (without fear of bumping the camera while changing out cards) until larger P2 cards come down in price, as well providing a means for archiving footage in multiple formats including DVCPro50.

Better yet, Is there a laptop PCMCIA card that converts analog component to DVCPro50, allowing laptop 4:2:2 capture on location -- or another way to accomplish this with a laptop? That'd be fantastic!

If not, is there an affordable PCI card for a desktop unit that does this? (Component to DVCPro50 4:2:2) Of course it would mean lugging a desktop computer to the job site, but for studio green screen work that might be well worth the tradeoff.

All this assumes that the component output from the Sony or JVC units, or Panny's new camera, are all of high enough quality (4:2:2 or better) to make all this worth the effort...
 
I should clarify my previous post-- I'm shooting SD, and the deck solution I mentioned above, the SD93, is SD.

My goal is seeing if I can come up with a way to approach SDX900 quality green screen keying and avoid DV25's 4:1:1 compression on our green screen segments. I know I can rent a SDX900, but we have weeks of green screen work ahead of us this summer, and I'm hoping I can put what would otherwise go into SDX rental into something that would approach that key quality -- a camera setup that I could come close to paying for, instead of pouring it into SDX rental.

Another way I could go, I guess, is to shoot HDV with one of these cameras (Sony or JVC) and pull my key before converting back to SD. Perhaps that would work just as well...

If noone's already evalutated this, I'll run some tests once Final Cut 5's shipping, borrowing a friend's Sony HDV, and can post the results if there's interest here.
 
joelnet said:
35mm print lenses have been resolving beyond HD for a long time. (OK, I know there are breathing issues when zooming etc. - but still Nikon and Canon have great lenses relatively cheap)
Click to expand...

35mm lenses resolve a lot less detail than an HD lens needs to achieve it's full rated pixel resolution on the CCD. A 35mm lens might resolve somewhere in the region of 40-50lp/mm, whereas the lens on a HDCAM needs to resolve 100lp/mm, and a 720p camera with a 1/3" CCD needs about 133lp/mm and a 1080p camera with a 1/3" CCD needs 200lp/mm. The smaller the imaging area for a given resolution means you need a higher quality lens.

Graeme
 
Hi just a note on lenses .both canon and nikon have primes capable of over 100lp/mm please ck out nikon 60mm f2.8 as an example.Don
 
Regarding the uncompressed idea. I've read thru the posts but I'm still a bit unsure.

I understand that you can get HD uncompressed analoge component
-Is this 4:4:4 or 4:2:2?
-Can I do 720p24 or is it just 720p60?
-Is the only way to capture this via Kona 2 HDSDI (or other card) straight into FCP (or other NLE)?
-Could you take the signal (still thru Kona) and use a different codec, say DVCProHD into standard drives?
-How would this analogue component signal look vs digital component.
-Would all menu adjustments, gama, etc, apply to the signal out?

Cheers,
Chris
 
-Is this 4:4:4 or 4:2:2?
Click to expand...
Analog is not 4:4:4 or 4:2:2 or x:x:x anything -- those are digital notations, and only apply to digital signals. Analog signals use sampling frequency, the details of which have not been disclosed yet as to how the JVC does it; I don't think we know how the Sonys do it either.

Frankly it could be the equivalent of 4:4:4, or it could be the equivalent of 4:2:0, or it could be the equivalent of 4:2:2, or the equiv of 3:1:1, or maybe even something else... I don't think any details have been announced. My guess is that it's more like 4:2:0, since in DV the chroma decimation step is unrelated to the digital compression step, and presumably in HDV it will be the same. But that's just a guess.

-Can I do 720p24 or is it just 720p60?
Click to expand...
You can only output 720/60p, but it will output the 24p images carried within a 60p stream. So, yes, you could output 720/24p, but when you go to capture it you'll be capturing 60p, and you'll have to identify and remove duplicate frames.

Is the only way to capture this via Kona 2 HDSDI (or other card) straight into FCP (or other NLE)?
Click to expand...
An HD-SDI card cannot capture an analog component signal. You'd need to either get an analog component HD capture card or, if getting an HD-SDI card, you'd need to get a converter that converts analog component into HD-SDI. You'd need a huge array of RAIDed hard disks as well.

Another capture option would be to a tape deck, like HDCAM-SR or D-5 (presuming, of course, that the deck has an analog component input).

-Could you take the signal (still thru Kona) and use a different codec, say DVCProHD into standard drives?
Click to expand...
Probably. But if you were going to do that, it might make more sense to get an HVX instead and avoid the conversions entirely (plus all the other features, including 1080i/1080p and variable frame rates).

How would this analogue component signal look vs digital component.
Click to expand...
No way to know until we see it. An educated guess would be that it's not going to be as good, but how different? Don't know.

Would all menu adjustments, gama, etc, apply to the signal out?
Click to expand...
From what I understand, yes.
 
The smoke seems to be clearing on a way to do high quality SD green screen studio work affordably while waiting on the new Panny. I've found that AJA's IO box (about $2k) will convert component (SD only) on the fly, direct into a Powerbook firewire port, and with final cut you can set the resulting capture to be uncompressed 4:4:4, DVCPro50, or anything you want, really.

And DVCPro 50 and maybe even uncompressed SD apparently is something one can capture using affordable accelerated firewire 800 drives, which La Cie says handle around 80 mbs. (La Cie has two flavors of firewire 800 drives, and the accellerated ones are almost twice as fast.)

So outfitting the powerbook with a PC firewire card to accept the AJA signal, and using the powerbook's built in firewire 800 port for the external drive, looks like a workable solution.

Then the trick, of course, is finding an affordable camera that ouputs SD component until Panny's new camera comes out, since it should do competent greenscreen work without much trouble.

Meanwhile, since Sonys and the forthcomming JVCs can switch between MiniDV and HDV, will either of them put out compenent SD when in MiniDV mode?

Thanks!
 
You must log in or register to reply here.
Back
Top