HVX-200 best possible pixel arrangement and count

[Gibby]

Clarification: I realize that the uncompressed 720p24 4:2:2 output from the HD100 is technically not HDV becuase it is ouput from the camera before HDV compression has been applied. I erroneously placed "HDV" after the 720p24 4:2:2 a couple of times in my previous post. Nevertheless, it as a workflow capability of the camera for certain projects.

Gibby
www.cut4.tv

 

[Barry_Green]

Do you mind running some numbers by us on the HD100 implementation of 720p vs what we can expect from the HVX? I take it the HDV codec will record a 33% higher luma resolution (1280x720 vs 960x720) but a lower colour resolution, which means...

Well... that's a lot trickier, of course. For theatrical work I think it's a given that people would shoot 1080/24p or 1080/30p on the HVX, which leads to the discussion above. I can't see why someone would shoot a lower-resolution format if they didn't have to...

So comparing HD100 to HVX on a basis of 720p-only presumes that there's some specific reason you're limiting the HVX to 720p. And if the HD100 is the competition, that presumes you'd be ruling out the HVX's huge advantages (60p, plus variable frame rate recording) so I would guess that what you are asking for is to engage in a purely theoretical discussion, as I don't think it would be reflective of the actual using of the cameras. So with that disclaimer out of the way...

For strictly 720p work, the numbers are different, of course. HDV 720p has 33% more luma, but DVCPRO-HD has 50% more chroma (it's 4:2:2, which should be 100% more, but it's not actually twice because we first have to take into account the fewer overall samples in the frame. If DVCPRO-HD's overall image frame was 1280x720, then yes there'd be 100% more chroma).

So HDV 720p = 1280x720 luma, 640x360 chroma. DVCPRO-HD 720p = 960x720 luma, 480x720 chroma. Twice as much vertical, 25% less horizontal... or, put another way, DVCPRO-HD, over the course of a full frame, has 50% more chroma samples.

But also 33% less luma.

But chroma on every line, vs. every other line.

It's tricky. Arguing numbers would probably lead one to believe that it would be more of a "wash".

Because of the resizing (1280 to 960 up to 1280), it's a little more difficult to compare. And, further complicating issues, I can't figure out how to get the Avid codec to work to compress 720p DVCPRO-HD. I can get 720p HDV, 1080i HDV, and 1080 DVCPRO-HD, but 720p DVCPRO-HD doesn't work right, it always gives me a magnified image. So before I could actually run the images through the compressor, I'd have to rely on someone out there with FCP-HD or Avid Express Pro HD who would want to run images so we could see.

I think the comparison between 720p HDV and 720p DVCPRO-HD will be much closer than, say, the comparison between 1080i HDV and 1080i/p DVCPRO-HD. The existing comparison test I was able to run (with the help of CJ Roy and Apple FCP-HD) is at: http://www.dvxuser.com/V3/showthread.php?t=26165&highlight=origineel

In that comparison, I didn't try to take into account aspect ratio conversions, presuming that an image captured by the camera would be captured at its native aspect ratio, so I didn't want to introduce PhotoShop resizing into the mix. It presumes that the camera would image at 960x720, and maintain 960x720 throughout the post process, so there wouldn't be any resizing going on. So I used images at their native resolution.

But HDV can technically store 33% more luma pixels, so that should be factored in somehow.

I think in the 24p configuration, HDV will have its best shot at looking as good as HDV can, because the most bits get spread around the fewest frames (hopefully, depending on how they implemented it... and how much may be wasted on pulldown frames in the 60p data stream). You can see how seriously HDV gets affected when it runs out of bits. 24P HDV should theoretically be the most resilient to running out of bits. DVCPRO-HD, as implemented on the HVX, will still retain three huge advantages, being 60p and variable frame rates and reliable/predictable compression behavior. But as to the distribution of luma vs. chroma, and the behavior of resizing vs. native, I think those factors will add up to make 24p HDV the most competitive flavor of HDV, and probably lead to the images looking, overall, the most comparable.

And given the fact that the CCDs in the HVX are likely to have more pixels horizontally than will actually be recorded by DVCPROHD at 720p, does the HD100 have any advantage in it's 1:1 pixel mapping of the CCDs at 720p? ie: do you lose anything by squeezing 1080 horizontal lines from the CCD into 720 lines in the codec?

Well, CCDs don't really work like that. You don't squeeze them, you sample the information off of them in the analog domain. More pixels than necessary would not lead to optimal video performance, I believe. But it doesn't guarantee that you're dead in the water either; the XL2 uses 960 pixels to create 720, and it makes for some awfully nice looking video (but, lower in sensitivity and latitude than the 720-pixel-wide DVX). So if the HVX CCDs are indeed 1080 lines tall, they could very well be giving up some sensitivity in comparison to the JVC, in exchange for providing higher resolution in the 1080p mode (although a case can be made that the HVX CCDs could theoretically function perfectly well at 720 pixels tall, for both 720p and 1080 modes, which would eliminate the loss of sensitivity). But the counter-argument is that the JVC is giving up some sensitivity by using native resolution when 960 would probably have served just fine; and if vertical spatial offset works as I suspect it must, they could easily have made the CCD 540 pixels tall and extracted just as much resolution (sacrificing chroma resolution, but then the codec is going to do that anyway, so there's no real-world net loss). That would have made the pixels a lot bigger than they are, so there's the possibility that the JVC is "wasting" CCD real estate, in pursuit of the marketing claim of "native resolution". However, if they come up with a native HD-SDI output board for a new model of the HD100, then they'd need that CCD resolution to support a 1280x720x4:4:4 signal, so they had to go with what they have.

So -- well... I dunno. That's a question that can only be answered by real-world testing. I expect both cameras will have around a million active pixels on their CCDs, so assuming a comparable level of technology, it would seem reasonable to expect comparable low-light/dynamic-range/noise performance from them.

So, again, we're straying away from things we can know (such as, how do the codecs deal with specific circumstances) into the realm of things we do not know (speculating on CCDs and how the cameras will perform). So many things could go right, or could go wrong, in the development of the whole imaging chain of these cameras, that all we can really do is wait and see. A camera will not be made or broken based on the number of pixels on its CCD, it'll be made or broken based on what it outputs to tape or disk or P2 card...

 

[Barry_Green]

any SD camera is going to produce better images than a HD camera downsampled.

For clarification, let me reiterate: an SD camera of comparable technology, comparable glass, etc. I wouldn't dream of saying that "any SD camera" could do better than a downsampled HD camera, because that would invite someone to compare downsampled CineAlta vs. native res from a $299 Handycam. Obviously the CineAlta would blow away the Handycam in any imaginable test.

So I was saying: 2/3" SDX900 vs. 2/3" VariCam downsampled to SD, using the same lens, yes, I do think the SDX might have the edge. Or 1/3" XL2 vs. downsampled 1/3" FX1 (keeping 16:9 to 16:9 here, keeping technology comparable) I would put my bet on the XL2.

So that brings up the question: How will the HVX or HD100 create a 720x480 image for dv from a much higher CCD? It must use some downsample algorithm or it could sample from a smaller part of the CCD. Either way is not ideal as the downsample will ultimately lose some clarity and to sample the smaller CCD would change the FOV or focal length to an unusable ammount.

I do believe there is validity to this concern. However, we must always throw in that old caveat, "all other things being equal." JVC and Panasonic have had three years to develop new CCD technology since the DVX first came out. It's entirely possible that tech will have advanced to the point where they can draw comparable SD performance out of the new denser chip. The argument could then be extended to say "yeah, but if they *hadn't* made the chip have so many pixels, they could probably get even better SD performance then!" And I believe that argument would be correct.

I am trying to be cautious as a camera intended for HD might have some drawbacks when trying to also cater to the DV crowd.

I can't really see how there wouldn't be. As to how significant the drawbacks are, I'm guessing that technology advances will overcome some (if not all), as compared to the current crop. And there will be other advantages that may offset any existing drawbacks: 480/60p on the JVC, plus native 16:9 chips... or DVCPRO50 on the HVX, plus (again) 16:9 chips.

For the DVX owner wanting to go to 16:9, the HVX is very promising, in that it brings two big advances: DVCPRO50 (very, very low compression, plus twice the color resolution) and 16:9 chips. For the XL2 owner looking to go to the HD100, there may be less incentive: the XL2 owner already has 16:9, and for SD use 480/60p may not be that compelling an upgrade.

(btw, I presume a higher % of DVX owners would be inclined to move to the HVX, since it's the same menus, same form factor, same batteries, same "looks", etc. And XL2 owners who bought into the concept of interchangeable lenses and shoulder-mount form factor would probably be more inclined to gravitate towards the HD100 than DVX owners would, I suspect. But that's just speculation).

It just seems that by design they cannot possibly do HD incredible and do SD as well as it should.

I don't know about "as well as it should", but I do think there's an argument to be made that it may not do SD "as well as it could" (could have if they'd left the chips at SD resolution, that is).

For many reasons I expect the HVX to be a better overall SD camera than the DVX is, primarily for DVCPRO50 mode, plus variable frame rates, plus P2 recording. But I do wonder if it'll have the same sensitivity as we've come to know and love on the DVX. I do believe that for some people, some users, the HVX's SD capabilities are enough, even without HD, for them to want to upgrade to it.

I don't know if the HD100's SD capabilities are enough to warrant someone wanting to upgrade to it. It's not really built around enhancing the SD experience, so much as it is focused on HD. If someone really wanted to get an interchangeable-lens SD camera, the DV5100 with its 1/2" chips probably will produce a better SD image than the HD100 (pure speculation, we don't know until we see it, but presuming SD-res 1/2" chips vs. HD-res 1/3" chips, it seems like a safe bet). I believe people who gravitate towards the HD100 will do so for two main reasons: 1) 24P HDV, and 2) how it looks. I don't think the SD capabilities are likely to prove to be too high on their list of requirements, since very very good SD cameras can be had for half the price.

 

[Barry_Green]

Interesting stuff Barry. How about running those hypothetical numbers for HVX200 DVCProHD 720p24 versus HD100 HDV 720p24, keeping in mind, of course, that neither camera has shipped or been tested.

I think I covered that in the response to Lacuna above.

I think HDV 720p vs. DVCPRO-HD 720p is one of those arguments that really won't play out that much in the real world. DVCPRO-HD does everything in 1080 mode that the HD100 does in 720p mode, and the HD100 can't do anything in 720p mode that the HD100 can't do in 1080 mode, so I don't really expect that people would choose 720p on the HVX unless they had to (i.e., shooting a series for Fox, for example, who might expect a 720p master).

And in that case, it sure seems on paper like the numbers make for an interesting matchup.

Since the HD100 has the ability to output analog uncompressed 720p24 at 4:2:2 color resolution, how about also running hypothetical colorspace numbers for that 720p24 4:2:2 HDV footage against the 720p24 4:2:2 DVCProHD footage.

Do we know what type of signal's coming out of the analog ports on either camera yet? It can't be 4:4:4, as that's digital notation, and the cameras are outputting an analog signal. Is the JVC really going to output the equivalent of 4:2:2? Or will the internal DSP decimate it to 4:2:0 before even starting processing? If it's not decimating it to 4:2:0, then why not leave it native at 4:4:4 (referring to internal processing, obviously when it's converted to analog for output those numbers aren't an accurate notation).

The analog outputs are, as far as I'm concerned, a wide-open game right now. I don't think anybody knows what resolution or sampling the signal will be on any of these cameras, all we know is that they all offer uncompressed analog output. On the JVC it's interesting because the worst part of that camera, in my opinion, is the HDV recording system -- and the ability to totally bypass it is just wonderful. But, that begs the question of: what will you do with that analog signal? How would you capture it? How would you record it? How would you store it, seeing as it takes 166 megaBytes per second to capture it?

Nobody should be surprised at all that 1080p24 4:2:2 footage has much more colorspace resolution than 720p24 4:2:0 footage

I know, but that's the question Lacuna asked; it was in relation to blowing up on the big screen, and in that case, obviously you'd use 1080, so the comparison of cameras remains valid (at least, as much as we can compare two products that don't technically exist yet!

but how about a 720p24 4:2:2 (HDV) vs 720p24 4:2:2 (DVCPRoHD) comparison?

Again, we don't know, and I don't think we can know, what the cameras are outputting. If the internal DSP decimates the signal to 4:2:0 before starting to apply gamma curves etc., then there's no way to get the equivalent of 4:2:2 out the ports.

Then again, if no chroma decimation happens until right before digital compression, then it's possible that you could see the equivalent of 4:4:4 coming off those analog ports.

And, since DVCPRO-HD doesn't get reduced to 960x720 until the digital compression stage, it's possible that its output would be an analog equivalent of 1280x720 at 4:4:4.

Or not. We'll have to see.

If someone wanted to compare the very cleanest signal they could ever get from these cameras, then the analog comparison is probably the way to do it. I think it's reasonable to expect that they will be of comparable technology levels, so if one has (the analog equiv. of) 1280x720x4:4:4, the other one likely will as well. And if codec chroma decimation happens prior to analog output, it'll happen to both (which would probably put the HVX in the lead then, since it would be 4:2:2 vs. 4:2:0).

Suffice it to say, one of the first things we should do is shoot some green & red fine-detail shots and pipe the analog output into a Blackmagic or Kona card, capture that and look at it blown-up and see what it's actually outputting!

BTW, any update on when you expect to get your HD100's? JVC's updated their site to say "august", and they've been telling resellers not to expect them before September; apparently there's even some fine-print on the sales stuff they're handing out to resellers that says "may not be available before September".

 

[thisiswells]

... begs the question of: what will you do with that analog signal? How would you capture it? How would you record it? How would you store it, seeing as it takes 166 megaBytes per second to capture it?

Right. to put things in perspective...

I would need a computer capable of playing back 32 simultaneous streams of DV to record and playback uncompressed HD ! Yikes !

 

[Barry_Green]

Of course, a very practical use for the analog out is to use it in a live studio environment, with live switching. If the signal doesn't need to actually be captured and recorded right there in the field, just fed back to a truck or something, then it becomes a very useful feature indeed.

 

[mmm]

For theatrical work I think it's a given that people would shoot 1080/24p or 1080/30p on the HVX, which leads to the discussion above. I can't see why someone would shoot a lower-resolution format if they didn't have to...

Could there be other factors that may hold back 1080p from being that much better than 720p on the HVX. A few people have questioned if the lens will be able to resolve more than 700-800 lines anyway.

If that was the case, would it be better to shoot 720p and have the advantages that go with it: 60p, lower data rates for editing/storage/P2.

Also does the DVCPRO-HD codec use the same "bits-per-pixel" to encode 720p and 1080p? I was wondering if, like HDV/ProHD, 720 would have a compression advantage?

 

[Barry_Green]

The lens issue is an open question, and one that can't be answered by speculating on chip pixel count. We'll just have to see.

If there was truly no advantage to 1080, it would seem awfully silly. I'm expecting there will be a difference, and most likely a significant one. But, we shall see. If there *is* no difference, then yes, people would likely shoot 720 instead for the longer record times in P2 and the variable frame rate capabilities.

DVCPRO-HD uses a fixed bitrate per frame. The compression is identical per pixel; 720p has half the pixels, but twice as many frames per second; 1080 has twice the pixels and half the frames per second; both have the same bitrate. So equal bits-per-pixel encoding.

 

[mmm]

I see, thanks Barry.

I guess that 1080p will be better than 720p, but whether low budget filmmakers will prefer 720p for the other advantages I mentioned above. If there is only a small difference in the two, I would probably go with 720p. Am I right in thinking that true 60/50p slow-mo is only possible at 720p?

 

[Gibby]

I can't see why someone would shoot a lower-resolution format if they didn't have to...

Some plausible reasons may be: 1) $10 high-tape versus $1,400 short-storage P2 cards 2) Professional features and results of detachable lenses 3) Shooting for a 720p network like Fox and mastering to 720p 4) Simultaneous backup to tape and disc 5) Easy long duration shooting of 720p in remote locations 6) Lower storage requirements for 720p than 1080p 6) and on and on... IE, lower or higher resolution isn't the only consideration. Content is king, and cost-effectively getting that content is the first consideration in a real-world, competive economy.

if the HD100 is the competition, that presumes you'd be ruling out the HVX's huge advantages (60p, plus variable frame rate recording)

Not necessarily, you may be considering the HD100's advantages over the HVX (see list above), the reverse side of which is that they can be disadvantages of using the HVX. The HD100 samples at 60p and records 720p24 or 720p30 that has been frame doubled down to 24p and 30p. If the motion smoothing filter at 30p ameliorates the judder, and it is able to play and slo-mo like 60p, what's the HVX's 60p advantage? Also, for hardlined television production, the HD100 will output uncompressed analog 720p60, so it's not as if it has no 720p60 capability. I think the camera will have a solid niche with Fox and others seeking cost-effective 720p60 HD-SDI converted hardline feeds. A&E networks executives, and several other networks had executives at JVC's NAB booth investigating that and the documantary capabilities of the camera. We won't know how effective the motion smoothing filter is until it is hands-on tested. As for variable frame rate, it's an awesome feature when you need it. I use a Varicam or SDX900 when I need that. Most shooters don't need that as often as they might think, plus you can simulate it with many excellent NLE plugins. For some genres of shooting variable frame rates is a major plus, for others, it will rarely be used.

DVCPRO-HD, as implemented on the HVX, will still retain three huge advantages, being 60p and variable frame rates and reliable/predictable compression behavior.

IBID - see discussion above. Reliable/predictable compression behavior is a solid agruement. No knowlegdable professional would argue that HDV compression has anything over DVCProHD compression, although it isn't disadvantage-free (costly recording medium). I have great respect for the DVCProHD format and use it regularly in my productions.

That's a question that can only be answered by real-world testing...So, again, we're straying away from things we can know (such as, how do the codecs deal with specific circumstances) into the realm of things we do not know (speculating on CCDs and how the cameras will perform). So many things could go right, or could go wrong, in the development of the whole imaging chain of these cameras, that all we can really do is wait and see. A camera will not be made or broken based on the number of pixels on its CCD, it'll be made or broken based on what it outputs to tape or disk or P2 card...

I couldn't agree more...It's going to be fun to finally get down to some field and lab testing. As always, I appreciate your inquisitive mind and attention to detail. I may not always agree with your conclusions, but I do enjoy the dialog...that's what a good tech chat board should provide.

Gibby
www.cut4.tv

 

[Gibby]

My input got pasted into the quote box on my previous post

Gibby
www.cut4.tv

 

[Gibby]

For the DVX owner wanting to go to 16:9, the HVX is very promising, in that it brings two big advances: DVCPRO50 (very, very low compression, plus twice the color resolution) and 16:9 chips. For the XL2 owner looking to go to the HD100, there may be less incentive: the XL2 owner already has 16:9, and for SD use 480/60p may not be that compelling an upgrade.

(btw, I presume a higher % of DVX owners would be inclined to move to the HVX, since it's the same menus, same form factor, same batteries, same "looks", etc. And XL2 owners who bought into the concept of interchangeable lenses and shoulder-mount form factor would probably be more inclined to gravitate towards the HD100 than DVX owners would, I suspect. But that's just speculation).

With media convergence and affordability of low-cost, high-capability camcorders and formats, I think dividing the production world up into "DVX owner", "Z1 oener", "Xl2 owner", "HD100 owner" is something that should be retired. There may be a certain percentage of tech chat board members that only have one camera (consumers to borderline prosumers), but in the production world of today competitive directors, editors, and shooters need to be capable in using multiple formats, and multiple camcorder types and models. For instance, I own the following cameras: Sony BVV400A, Sony DSR300A, JVC DV500U, Canon XL1s, Sony PD150, Sony VX2000, Sony TRV900, several Sony lipstick cameras. I regularly rent the following cameras: Sony F900, Panasonic Varicam, Pansonic DSX900, Igegami DVCPro50 cameras. In summary, I own and rent professional cameras form all of the major manufacturers, and I own "competing prosumer" comeras form each manufacturer. I know many, many other professional shooters and directors who do the same. We simply match the paint brush to what we're going to paint that day. We don't see different cameras as competitors, we see them as different tools - and then we match the best tool to each job. Nothing irritates me more than to be categorized as a "JVC guy", "Panasonic guy", "Sony guy", "Canon guy", "video guy", or "TV guy"! I'm a PRODUCTION GUY who has the sense to put my biases and ego aside, and use the best tool for each job. There is a whole lot of us out here in the professional world. Most of us avoid the "prosumer" tech boards because they are replete with brand-specific factional bickering. We don't have time for brand-camps, we just have time to learn and share - otherwise why visit tech boards when our schedule is already hyper-busy?

Barry, you're a pro-level director and shooter, and I'm sure you use cameras from multiple manufacturers. I'm probably singing to the choir, nevertheless, there's some input from the front lines...

Gibby
www.cut4.tv

 

[Barry_Green]

Some plausible reasons may be: 1) $10 high-tape versus $1,400 short-storage P2 cards 2) Professional features and results of detachable lenses 3) Shooting for a 720p network like Fox and mastering to 720p 4) Simultaneous backup to tape and disc 5) Easy long duration shooting of 720p in remote locations 6) Lower storage requirements for 720p than 1080p 6) and on and on... IE, lower or higher resolution isn't the only consideration. Content is king, and cost-effectively getting that content is the first consideration in a real-world, competive economy.

Hey Steve, I think you misunderstood what I was saying. When I said "why shoot lower resolution" I was referring only to the HVX. As in, why choose to use 720p when you've got 1080p at your disposal? Why shoot the lesser format? And, if you're considering the HD100 as the "competition", i.e., you would either shoot HVX or HD100, then you've already settled that you'll only use 720/30p or 720/24p. And the HVX offers those modes in 1080. So if you're shooting on the HVX, why limit yourself to 720, when you could flip a switch and shoot 1080? That's what I meant.

I wasn't saying "why shoot on the HD100 when you could shoot on the HVX instead" -- because obviously there are many differences between the cameras, as you clearly elucidate. And, by the way, I agree with you in all your assessments there, which is why I am buying an HD100 in addition to the HVX.

The HD100 samples at 60p and records 720p24 or 720p30 that has been frame doubled down to 24p and 30p. If the motion smoothing filter at 30p ameliorates the judder, and it is able to play and slo-mo like 60p, what's the HVX's 60p advantage?

It's not going to look like 60p. I haven't seen it, because they didn't have it working, but there's no way it can do it. Square pegs and round holes. I believe it can make it look a little smoother, yes, at the sacrifice of some resolution. It's blending frames together. In some ways you could look at it as the same question of "what's the advantage of progressive scan, if you can just de-interlace?" Because they're not the same.

The 60p-blended-to-30p footage will probably look an awful lot like shooting 30p with a 1/30th shutter. And 30p with a 1/30th shutter is definitely smoother than 30p at a 1/60th shutter, but it looks nothing like 60i or 60p.

Again, speculation, we don't know. But I don't believe JVC has ever made the claim that their motion-smoothed footage would look like 60p; they've only said that it would smooth out some judder in 30p footage (or, optionally, in 24p footage).

Also, for hardlined television production, the HD100 will output uncompressed analog 720p60, so it's not as if it has no 720p60 capability. I think the camera will have a solid niche with Fox and others seeking cost-effective 720p60 HD-SDI converted hardline feeds.

Completely agreed. I believe that is where the HD100's uncompressed output will be most useful, and I definitely expect to see the cameras employed in that capacity. Especially with the ability to mount 1/2" lenses, they will be able to get much more telephoto reach out of them. And the uncompressed 60p did look pretty darn good at NAB. I don't anticipate many end users trying to take advantage of uncompressed 60p, but it will most definitely be appropriate in news & sports coverage in a hardline, cabled situation.

As for variable frame rate, it's an awesome feature when you need it...Most shooters don't need that as often as they might think

Yes, it is an amazing capability, and no, it probably won't be used all that often. But I think the lack of 60p recording is a significant drawback, and one that would be used very very often if it was present. Perhaps we'll all be surprised, perhaps the motion smoothing filter will work wonders, but I can't imagine how. I do look forward to trying it.

For some genres of shooting variable frame rates is a major plus, for others, it will rarely be used.

Agreed. Which is why I expect that most HVX shooters will just use 1080p instead, and will likely revert to 720p only when they need variable-frame-rate capability.

As always, I appreciate your inquisitive mind and attention to detail. I may not always agree with your conclusions, but I do enjoy the dialog...that's what a good tech chat board should provide.

Agreed indeed -- I appreciate your experience and your participation, and especially that we're able to disagree gentlemanly (although, truthfully, I don't think we disagree that much, I think it's more my fault in not making what I was saying as clear as it should be).

 

[Barry_Green]

Nothing irritates me more than to be categorized as a "JVC guy", "Panasonic guy", "Sony guy", "Canon guy", "video guy", or "TV guy"!

Of course that's not what I meant. I would guess, on a conservative estimate, that 90% of the users of this board, and DVInfo, etc., own at most one of these class of cameras. That doesn't make them "a Canon guy", for example; it makes them a current XL2 owner. And they didn't necessarily choose the XL2 because they're a Canon fanatic, but because it offered the features they wanted. Which is why I said that those customers, who made their equipment choice based on the features offered, would probably be more likely to be attracted to the JVC HD100, because it offers a similar feature set.

No doubt there are brand bigots out there, and die-hards who will support one manufacturer blindly. In the professional world it happens as well, but it's an old and tired mentality that needs to be retired as soon as possible!

 

[Gibby]

Barry Green: "I believe people who gravitate towards the HD100 will do so for two main reasons: 1) 24P HDV, and 2) how it looks."

To those reasons, I would add: 3) Affordable recording medium for 720p 4) professional utility and creativity of a detachable lens 5) no need for 1080p recording 6) the high storage requirements of 1080p 7) easy and affordable simultaneous 720p backup recording to tape and portable HDD 8) ease of in-camera upconverting of 720p to 1080i for networks (ABC, ESPN, HDNET) and projects that require 1080i. 9) 720p30 sampled at 720p60, if the motion smoothing filter works as advertised, and resolution is not significantly diminished 10) 720p60 uncompressed analog to HD-SDI output for live television and satellite uplink purposed 11) long 720p24 storage times on tape and HDD for mobile documentaries, nature shooting, etc. And on and on...

That said, the HVX200 also has many advantages over the HD100 (solid compression scheme, many more resolutions and frame rates, etc.). I'll be buying two HD100's, two HVX200's, and I already have one Z1, and onother Z1 on the way. In two's we have the ability to always have a Camera A/Camera B crew, with footage that matches perfectly. All these "competing" cameras are excellent tools when amtched to an appropriate project...I don't see them as "better" or "worse", I just see them as different...

Gibby
www.cut4.tv

 

[Gibby]

Barry Green: "Do we know what type of signal's coming out of the analog ports on either camera yet? It can't be 4:4:4, as that's digital notation, and the cameras are outputting an analog signal. Is the JVC really going to output the equivalent of 4:2:2? Or will the internal DSP decimate it to 4:2:0 before even starting processing? If it's not decimating it to 4:2:0, then why not leave it native at 4:4:4 (referring to internal processing, obviously when it's converted to analog for output those numbers aren't an accurate notation)."

I had a long conversation with a JVC engineer at the NAB JVC booth about as many tech specs on the HD100 as I could weasel out of him. His business card also identified him as an engineer for JVC. I specifically asked him if the uncompressed analog 720p60 output was 4:4:4 or 4:2:2, and his distinct response was that it was 4:2:2. If he was right, that is a big improvement over it being 4:2:0, but a manageable data stream compromise when compared to 4:4:4. It's possible that he head his info wrong, and it's 4:4:4 or 4:2:0, but I'm used to figuring out real quick if someone is truly knowledgeable, or is s smoke blower. At this point, I have to assume that he was correct, and that it is a 4:2:2 output. I hope it's at least 4:2:2 because it increases the utilitarian value of the camera. Believe me, I'm no fan of HDV's 4:2:0 color resolution, but I understand it was necessary to successfully compress data to 25mbs and 19.2 mbs for the HDV spec.

The dialog today has been informative. I agree that we have agreed much more than we have disagreed. Time for me to sign off for a few days. I'm being flown to Phoenix to be a panel leader for the judging of the Emmy Awards (Rocky Mountain Southwest Region).

C-ya!

Gibby
www.cut4.tv

 

[Barry_Green]

I don't see them as "better" or "worse", I just see them as different...

The more different the cameras are, the les I'm concerned with which is "better", because "better" is obviously directly related to a specific purpose. For example, which is "better": a motorcycle, or a pickup truck? They're obviously extremely different, and excel at different things.

The more similar they become, that's where "better" comes into play. The HD100 and HVX are different enough that it's hard to choose "better" between them. The HD100 and XL2 are similar enough that it seems pretty easy to choose which would be "better" -- the HD100 (assuming its performance holds up to the promise).

The HVX and Z1 are similar enough (same form factor, etc) that it's easy for me to choose which one I find astoundingly better -- the HVX.

But "better" between the extremely-dissimilar HVX and HD100 is a much more difficult question to answer; unless a user has a particular need for one of its features.

 

[USLatin]

So it just kind of pukes and gives us a slightly-red green.

:grin: ROFLMAO!! :grin: Dude, you are going to make me cry! LOL!!! That was AWESOME!!! ha ha ha ha ha!!!!!!! The guy's got humor AND he gratuitously shares volumes of knowledge with great clarity!!!! Come on, somebody postulate him for President or something!


:thumbsup: Barry Green is my idol! :thumbsup:

 

[Graeme_Nattress]

I don't think 4:2:0 is "necessary" for HDV to get the size down small enough, but it's a bad decision nether-the-less. 4:1:1 would take the same amount of data, and although it sounds bad, is actually much better as it doesn't work differently in interlace v progressive video and is easier to improve using clever algorithms. I'd perfer 4:1:1 to 4:2:0 any day of the week.

Also, it's really wrong to talk about analogue outputs in terms of 4:2:2 or whatever. Analogue signals are measuered in terms of signal to noise ratio (sort of equivalent to bit depth) and bandwidth (resolution).

Graeme

 

[Thomas Smet]

Barry,

There could be many reasons why people would use 720 on the HVX for film production over 1080 mode.

1. only 720p mode allows variable frame rates.
2. 720p at 24 uses less than half the datarate of 1080p at 24p. That means more recording time on P2 cards, less storage space, more real time editing streams and overall better editing performance.
3. Shoot 60p for perfect slow motion.
4. Match a film production shoot with a Varicam.

I'm sure there are other reasons.



I agree with Graeme on the 4:2:0 issue. It wasn't until I started writing a program to upsample HDV chroma that I realized how bad it is. With 4:1:1 at least you know every forth chorma pixel on a line has the accurate U and V chroma pixels. With 4:2:0 in some way every single pixel has some form of chroma interpolation going on. Because 4:2:0 alternates every other channel on every other line that means line line will have nice 4:2 samples for U but all of the V samples are interpolated. The opposite happens on the next line. So if you scaled down an HDV frame to 1/4 of the size to 720x540 you pretty much have a 4:4:0 or a 4:0:4. You can get accurate samples for the U pixels but every V pixel directly behind with be interpolated. 4:2:0 would have been much better if they would have just left the U and V pixels on top of each other and totally interpolated both the U and V every other line.



I actually slightly disagree about pixel shift being just as good as the full resoultion. If that were the case DV and other SD cameras could be made with chips that are 540x480 and they would look just as good as if they were made with 720x480 chips.


I actually think the chips will be 1280x720 on the HVX. The reason for thinking this is because of aspect ratios and anamorphic pixel issues. If the chips were 960x720 they would be anamorphic with a 1.3333 ratio. The problem is that the 1080 mode is a 1.5 ratio. With the chips being 1280x720, however the varicam gets 960x720 from its 1280x720 chips will be used here. For 1080 you can muliple 1280 x 720 x 1.5 to get 1920x1080 for the correct 16x9 aspect ratio. That means all they need to do is offset the 720 by 1.5 and leave the 1280 as it is.

Barry did bring up one interesting point I didn't think of at first. offsetting the vertical would end up giving us a 4:4:2 from the chips. After compression we would end up with a form of 4:2:2 that would be more like 4:2:0 for the 1080 mode.