Doug,
This article mentions what you're seeing using the Studio's component inputs:
http://www.dv.com/reviews/reviews_item.php?articleId=196603088

It also mentions try to capture at a higher bit rate to reduce softening.
For ex. Capture at 10bit for 8bit video.

Have you tried this?

It also mentions using the card in conjunction with firewire (from a port not on the card)

This doesn't immendiately make a lot of sense to me because I can't figure out what connection there would be between the card and a separate port on the computer.

Does anyone know what he's talking about and how the card would be in the path for a firewire capture?

Doug,

Because the camera is already D from the get go and to produce analog it would have to first do a D to A conversion. So inputting analog would then effectively have a D to A step followed by an A to D step. At least going via firewire, the whole process is digital.



I routinely peruse the postings about the JVC camera because I am considering buying a HD110 or 200. So, I was interested to follow this discussion about the best way to capture a high quality signal. But, when I came across this thread I had to jump in because this statement is, to my knowledge, incorrect and thus leads the discussion down the wrong path.

Video capture is inherently analog (light is not digital). A CCD registers the light hitting it by converting it to an electrical (i.e. analog) signal. That is the sole purpose of the CCD. So, with that signal being analog, using Jim's words, the camera is really ANALOG from the "get go." AN A/D convertor is then introduced into the signal path to sample the signal and convert it to a digital one before recording to tape or otherwise routing the signal to an SD-HDI connector etc. (In comparison, the old analog cameras actually recorded the ELECTRICAL signal straight to the tape.)

So you can see that it would be relatively simple to route the electrical/analog signal around the AD convertor to the component (or composite) out and feed this "uncompressed" signal to another device which can compress it at a different specification than is otherwise required for recording HDV to mini-DV tape (with the limitation of a data stream of less then 25Mbps). Hence the potential for recording "uncompressed" from these sources as long as you have the right equipment to ingest the full bandwidth of the electrical signal. Obvioulsy, the end quality of your new recording is completely dependent on the spec and quality of your AD conversion path.

And just a note about Firewire output - Firewire only carries a digital signal and its bandwidth limitations constrain it such that, in this case, it can only carry an HDV (i.e. compressed) signal. This signal is indeed post AD conversion - the same signal that gets laid to mini-DV tape in an HDV camera.

There is a great ebook about the JVC ProHD series available on the JVC site that explains in detail how these camera work. (It does cost $40 but I found it worthwhile and, no, I don't get anything for recommending it.) Also there is a good white paper about the JVC philosophy and their choice of codecs, etc. (It's free!) Both can be found on the http://pro.jvc.com web site. Navigate to the page about the GY HD-110 and click on the "Color Brochures" button. Both are there. (I tried to post a direct link but it doesn't stay intact. Sorry.)

Hope that is helpful.

Terry

Terry,

Actually, there is no such thing as digital. Everything is analog (this may be the dirty little secret of the computer age!) and digital is fantasy!

However it is a very convenient and useful fantasy/abstraction - particularly for me as I've been making a living exploiting this fantasy since 1959!

So of course I agree with you that everything in the camera is a set of analog states such as charge levels on the sensor, and in the various components.

However, I still think it unlikely that the camera ever has the pure analog signal available to route around all the digital processing.

In particular, as JVC says elsewhere on the web site, the data from the sensors is sampled in two halves, ie right and left of the sensors to prevent overheating of the sensor chip. I think it is very unlikely that this would be compatible with maintaining the possibility of a pure analog flow through the camera since the word "sampled" seems to imply (at least to me) that the data are already in the process of being "digitized".

There are also a lot of things such as white balance etc going on that I doubt are being performed in analog circuitry - digital processes for these functions are so much more compact and cheap these days.

I'd really love to find out what the real data flow in the camera is but absent some kind of block diagrams from JVC I think we're all in speculate mode!

Terry,

Actually, there is no such thing as digital. Everything is analog (this may be the dirty little secret of the computer age!) and digital is fantasy!

However it is a very convenient and useful fantasy/abstraction - particularly for me as I've been making a living exploiting this fantasy since 1959!

So of course I agree with you that everything in the camera is a set of analog states such as charge levels on the sensor, and in the various components.

However, I still think it unlikely that the camera ever has the pure analog signal available to route around all the digital processing.

In particular, as JVC says elsewhere on the web site, the data from the sensors is sampled in two halves, ie right and left of the sensors to prevent overheating of the sensor chip. I think it is very unlikely that this would be compatible with maintaining the possibility of a pure analog flow through the camera since the word "sampled" seems to imply (at least to me) that the data are already in the process of being "digitized".

There are also a lot of things such as white balance etc going on that I doubt are being performed in analog circuitry - digital processes for these functions are so much more compact and cheap these days.

I'd really love to find out what the real data flow in the camera is but absent some kind of block diagrams from JVC I think we're all in speculate mode!

Well - since I was just entering first grade in 1959, and they didn't have an engineering major in my pre-K classes, you've got me on the time frame. :-) And I can't argue with the idea that everything is mere speculation - as the creationists love to point out to the scientific community. So, I have no choice but to let a combination of "facts" (at least as we think we know them) and logic inform my own "speculation."

We agree (I think) that the signal coming out of the component output IS analog (by definition, as stated by the camera mfgrs, and as testified to by common usage). There have been component (YCC) signals since before video cameras were digital. This signal carries electrical "components" of one luma and 2 chroma. Since the engineers designing the camera presumably intended to include this capability, why would they choose to digitize the signal (AD conversion) and then reverse the process (DA conversion) in order to allow for this? It would almost certainly result in a lower quality and would require much more circuitry. So, while it might be an bit of an engineering "inconvenience" to tap the analog signal just after the CCD, it can't be any more arduos and inconveneient than the multiple conversion process. Can it? Why not believe that they purposely design the circuitry to tap the analog signal and route it to the component out?

As for the white balance function - that is an adjustment that is actually applied to the chips themselves to balance the sensitivity to the specific colors so, no, it wouldn't require digital processing. It is essentially "adjusting" the CCD chips to tweak their light sensitivity - just as boosting the gain is. After all - you can't alter the WB (or gain) from the camera after capture, even within the component signal (tweaking it in post doesn't count because that's a different proces), so why is that part hard to believe?

So, with the HD110/200 there are two signals through the camera. One routes the analog signal to the component out - full uncompressed YCC signal ready for AD conversion by an external device. The other routes through the AD conversion chipset to be "sampled" and, thus, converted. It is here (in the AD conversion) where the two halves are sampled separately - yes, to prevent overheating - and result in a digital signal.

Perhaps where we might be getting hung up is whether these two processes are embedded on the same tiny circuit board or not. They might be on the same "chip" but they are not the same circuity. My contention - based on what I believe to be facts and logic - is that, since an analog signal IS captured by the CCD (and can be electrically tapped at that point), and a high quality analog signal IS available at the component output, there is little reason to suspect that the pathway from one to the other is more complex that it need be. The quality of the component signal is purely a product of the quality of the CCD - not the AD conversion. And it happens that JVC has high quality CCDs and thus a very good component signal.

And to finish the explanation - the digital route in the 110/200 goes from the capture CCD, through the AD conversion process and THEN is compressed to be laid to tape AND sent out the Firewire. Hence, the ability to record an HDV signal simultaneoulsy to a hard drive capture device. Note that the sampling process and the compression process are different and separate prcesses! (Which is one reason the HD200 create a better digital signal and is more expensive).

The HD-250 offers on additional path. After capture by the CCD and conversion by the AD convertor but BEFORE compression, the signal is routed to the HD-SDI port which is an uncompressed version of the digital signal. (The HD-SDI port, if I am not mistaken, is the sole difference between the HD-200 and the HD-250.) To be quite clear, the "sampling" does a certain amount of data reduction simply by the limits of the AD conversion process but this is NOT the compression we are talking about when we talk about HDV compression and the resultant 4:2:0 color space. That compression is driven by the HDV/MPEG-2 standard as agreed to by the industry and which is driven by the need to keep the signal bandwidth low enough to be recorded to the same mini-DV tape which became the standard in the SD DV era (before HD and HDV).

Again - I hope that helps. If you still think I am "speculating" I guess I'll have to accept that. Unless, of course, there are any known facts to dispute my "speculation."

:-)

Best,
Terry

Well - since I was just entering first grade in 1959, and they didn't have an engineering major in my pre-K classes, you've got me on the time frame. :-)

cut....

:-)

Best,
Terry

Dear Terry and Jim, reading your posts brings to mind a quote from "Butch Cassidy and the Sundance Kid". To paraphrase the quote: WHO ARE YOU GUYS??

Dear Terry and Jim, reading your posts brings to mind a quote from "Butch Cassidy and the Sundance Kid". To paraphrase the quote: WHO ARE YOU GUYS??

Not sure I understand the nature of the question. I am assuming a certain amount of sarcasm. Did we intrude on a private conversation?

It's my understanding that the digital data available (after compression) via the firewire port or the tape, is 4:2:0, 8-bit. The analog data available from the component ports is sampled at 4:2:2 and delivered at the equivalent of 10-bit. This implies a A-D process directly from the CCD block, which JVC advertises as 12-bit. The digitized signal, at this point, follows one of two paths, as follows:
1- it undergoes compression for tape or firewire delivery(HDV specification is for 4:2:0, 8-bit)
2- it is converted, once more from D-A for analog delivery to the component ports. Once again, the processing engine is maintained at 4:2:2, 10-bit.

Not sure I understand the nature of the question. I am assuming a certain amount of sarcasm. Did we intrude on a private conversation?

Nah, just impressed with the tech fluency. Was wondering if you guys are engineers or something.

50 years ago I couldn't even spell "enjinear" and now I is one!

Not an engineer, just an old guy who was majoring in Physics and Chemistry and somehow got into computer programming in 1959 and has been living around the damned things ever since.

Once upon a time long long ago I wrote firmware for some unique military systems and have hung around with hardware designers for - decades. Long enough to pick up the concepts, even if I couldn't design a circuit if my life depended on it.

I'm really just trying to formulate a model in my head of how these cameras really work and where in the process various things like compression and up/downconversion and sampling take place

Everything I say is probably wrong (as my wife likes to remind me) so don't take any of this too seriously.

Bill, - if the analog out is so good, why does it look so bad after capture via a Blackmagic card? Unless their A to D is really bad, which I would tend to doubt) On the other hand, anything is possible.

I guess this all started as I was wondering whether capturing the analog (which would have as you say been at 10 bit 4,2,2) would yield better color than an upconverted 4,2,0 captured over firewire.

The pictures that were posted here however indicate otherwise.

Tis a mystery.

I remember reading / hearing that component to SDI looks great out of the JVC HD100. This makes me believe that it's Blackmagic's A/D converters and/or analog circuitry.

Well, I guess it's plausible. Anyone have better results with a different card?

I sent an e-mail to Blackmagic asking them why they thought the analog input would look so bad, but I never got a reply.

Maybe I should scratch them off my list!

I think there's a lot of variables that get included in the workflow. I know that a helluva lot depends on the kind of display monitor you're looking at. Unless you've got an HD monitor, things will actually look worse on a standard NTSC monitor. Are you viewing 1280x420 or have you downconverted? What color map are you using rec 601 or rec 709?

And, what processing steps are you using to display after capture? Are you going straight to a playback software, or are you running thru an NLE? What are the default injest settings on the NLE? So much that can affect the final output that it's rerally hard to make a realistic conclusion.

I did a test using Adobe CS3 to capture analog component 1280 x 720 8bit 60p through a BM studio card, and at the same time captured 30p to tape, them imported through 1394 port into Avid Liquid. The difference is very noticeable. I posted a mp4 file, because of file bandwidth issues, to show people what they can expect to get out of this combination. Even the HDV portion of the mp4 has more resolution then the analog component capture.

http://www.portstanleynews.com/TV/JVCTest.mp4

I will do another test with a Canon HV20 to check the difference of HDV vs HDMI

Bill,

I was referring to the example that Doug Harvey had posted for us a while back.

For whatever it's worth, I sent an email to Blackmagic, asking what the A-D sampling rate was for their Intensity Pro bus card. They replied with this answer:
"Unfortunately, I don't have an exact specification but that it's using a new
analog design which is even better quality than all our previous products.
This analog design will be used in our new Multibridge Eclipse. Hope that
information helps a bit."

Why wouldn't they know the answer to this critical question? Implied message: Our A-D converter ain't that good?

Bill,

Thanks for bugging them. I sent a couple of e-mails on the same subjec, even including a link to Doug's post, but no response at all.

I wonder, though, whether the Intensity Pro is newer than the Studio card - could be they meant to say that they've improved the A to D.

On the other hand - maybe the Tech SUpport folks just don't know! Or maybe nobody knows! Or maybe it isn't very good. In any event, paying the money for one without having a better idea of the quality doesn't sound too smart to me.

By the way, just noticed that you're in Santa Fe. My wife and I were there a few weeks ago for the opera. Very nice place.

Jim...

Every software/hardware manufacturer builds their products out of commercially available micro-ships. Unless, of course, they make their own chips, which I HIGHLY doubt for places like BMD. This being the case, ANYONE who owns a BMD product can open the case(at the risk of voiding the warrantee, of course) and look at which A-D micro-chip BMD uses. Of course, the Intensity PCI bus card is plainly visible. A simple web search from the chip part number will produce the specs for that chip, including the sample rate. I find it VERY hard to believe they don't know what's in their box!

Yeppers, grew up in Tucson-town, tho'. My mom still lives in the Tucson foothills, out by Gates Pass.Went to college at the U of A.

I actually thought about trying to find out the chip info, but I think the chip can be driven differently depending on what you want out of it. I know we use analog modules from Allegro to control the motors in our tape drives, but there is a lot of fooling around in the firmware that talks to the chip itself and in some cases we actually stick an additional chip in line with the Allegro module to mask some of its normal behavior from the firmware

Oh well we're getting way beyond my area of inexpertise.

We're in the foothills North of town - near Swan and Sunrise if you remember the area. We looked in the Gates Pass area when we moved here last year from the San Francisco area. So far we like it. I've been coming here for business since around 1978 so I had some idea of what it was like. My wife was a bit surprised to see a bobcat on our front steps the first week we were here. Not as bad as the mountain lion breaking into the jewelry store in the middle of Santa Fe a few weeks ago, though. Sure wish they had caught a video of the cat coming through the front door.

Like Jim, I sent the same questions and link to this thread to Blackmagic about three weeks ago. No reply

I wish someone would chime in that actually owns the Intensity Pro and has used the component inputs. I want to use it and capture to Cineform from my HD100.

Some actual short, full rez samples would really help my decision.

BTW, I live one hour north of Tucson, Casa Grande, AZ

Interesting info in this link:
http://www.dvinfo.net/conf/showthread.php?t=103540

Hi everyone,

Looking for some hints.

What actual benefits the BR-HD50 + HD-Connect MI (as a HDMI to HD-SDI converter from the BR-HD50) could give me compared to a HD-Connect SI converter between my GYHD201 and a NLE system equipped with i/o HD-SDI connectivity? Or shorter, what are the plus values of the BR-HD50 in a system like that, besides its playing/recording capabilities?

Thanks very much for your inputs.

Philippe