Recording 12-bit 1080P ProRes from HVX200 Component Out

[ozzymandius]

I will be shooting a feature very soon, and am considering getting an AJA KI PRO, as I am aiming for cinema screen quality. Based on my research this recorder should allow me to record 12-bit HD from the RGB connectors of my HVX200 directly into ProRess 422.

http://www.aja.com/pdf/AJA_KiPro_Brochure09.pdf

-- Am I correct in this assumption?

If so, I am hoping to get some tech feedback to make sure I've got this straight.

-- First, will the analog signal off the RGBs really be much better quality than DVCProHD on P2? Can someone please explain that? I find it hard to imagine.

-- Can I get all frame rates, and all modes (e.g. 1080 Pn) from the camera when tapping the RGB out, or are there some limitations?

-- The AJA supposedly does its A/D conversion at "12-bit, 2x oversampling" but also seems to have 10-bit modes. Will there be a noticeable difference between a 12-bit vs 10-bit conversion?

-- It allows recording to ProRes 422, ProRes(LT), ProRes 422(HQ) and ProRes 4444. Excuse my ignorance, but which format is best?

-- If we assume a theatrical screening, how much "better" would this AJA recorded footage compare to P2 footage - both at best quality? Now I know that's a loaded question as it all depends on how it's all lit and shot. But assuming everything else was equal, are we talking a major quality improvement noticeable even to my grandma? Or a very minor improvement noticeable only to professionals who are paying very close attention?

-- Are there any disadvantages or dangers or quality issues that I should be aware off when attempting this?

Any input much appreciated!

 

[maranfilms]

4:4:4 is the best it has twice the info of 422. In some cases it takes two sdi connections to make 4:4:4. Google chroma subsampling for a better explanation than I can explain. It's hard for me to put into words.

 

[Jarek Zabczynski]

Correct me if I'm wrong. I thought KiPro only records to ProRes 422 HQ. Either way, you should get a slightly higher resolution and an overall cleaner image with less compression.

 

[kwoff]

Correct me if I'm wrong. I thought KiPro only records to ProRes 422 HQ. Either way, you should get a slightly higher resolution and an overall cleaner image with less compression.

It is also my understanding that the KiPro does not record ProRes 444, only 422 HQ, which is a very solid codec as well.

 

[ozzymandius]

Right. It's 422 HQ, though I thought I read on a message board somewhere that a firmware update allowed it to record 444, but I may be mistaken.

 

[TheReverend]

-- First, will the analog signal off the RGBs really be much better quality than DVCProHD on P2?

-- Can I get all frame rates, and all modes (e.g. 1080 Pn) from the camera when tapping the RGB out, or are there some limitations?

These are really the only questions that need answering. I mean, the KiPro will have fantastic quality recording of whatever the source quality is. ProRes is simply a fantastic codec to work with. Is the analog to ProRes better than sensor straight to DVCPROHD? I would guess not, but really it's only a guess. Analog in my mind has the possibility of signal degradation and loss.

That being said, RGB outs as far as i know are typically 720p/60 or 1080i/60. I don't believe you can send any different signal out the ports because the signal has to comply with HD analog standards. Shooting at 720/24pn on the P2 cards will probably get your truest theater frame rate. If you shoot at 24fps recording out the port, the component port might show 24fps but the true signal I suspect will still be 720p/60 or 1080i/60.

All this being said, using an HPX170 with the HDSDI out to KiPro would be the best option. You stay digital, get ProResHQ quality with instant harddrive access to FCP, and looooong record times. A win, win, win!

 

[DDort]

The Ki Pro will never record ProRes 444. You would need dual link HDSDI connections and the Ki only has single link connection.

And, TheReverend is right, you should find out which framerates the HVX outputs through it's SDI port.

 

[TheReverend]

And, TheReverend is right, you should find out which framerates the HVX outputs through it's SDI port.

HVX doesn't have an SDI port. HPX170 does.

From the HPX Operating manual-
CMPNT or SDI out = 720P/1080i/480i
So yes, the CMPNT out will be 720p60, 1080i60, or 480i

 

[ozzymandius]

So yes, the CMPNT out will be 720p60, 1080i60, or 480i

Is that signal uncompressed?

And if recorded by the AJA, can't the 1080i60 signal be converted to a 1080 24p ProRes format?

My limited understanding of the HVX is that DVCProHD essentially takes the 1080i60 signal and compresses it down onto the P2 card as 1080 24P (or whatever frame rate was chosen). And that the advantage of the AJA is that it can do the same thing but with much less compression.

But I'm still not sure.

Barry Green to the rescue?

 

[TheReverend]

Is that signal uncompressed?

Yes, but it is analog which is... well analog. It isn't a higher quality signal than what the camera has internally.

My limited understanding of the HVX is that DVCProHD essentially takes the 1080i60 signal and compresses it down onto the P2 card as 1080 24P (or whatever frame rate was chosen). And that the advantage of the AJA is that it can do the same thing but with much less compression.

Not exactly. DVCPROHD as a format is constrained to 1080i60, or 720p60 as the "stream" format. However, the actual data inside the stream is variable, frame rate included. Basically if you record at 720p24, but NOT in native mode, the "stream is 720p60, but encoded with advanced pulldown algorythms to achieve a 24p frame set. At 720p24PN or native, the DVCPROHD stream is literally only 24 frames. Native modes are going to be the most frame accurate.

The AJA would still be translating a 1080i60 signal to ProRes. Is ProRes better than DVCPROHD? Yes. Is the component signal to ProRes better than the camera internally straight to DVCPROHD? Not likely.

 

[Barry_Green]

-- Am I correct in this assumption?

Are you correct in the assumption that the KiPro will allow 12-bit HD to be recorded? Probably, but be aware that you're likely not going to get a full 12 bits of data out of the analog system. It's probably not going to need more than 10 bits, and if I had to bet, probably more like 8, to capture all that's being output.

-- First, will the analog signal off the RGBs really be much better quality than DVCProHD on P2? Can someone please explain that? I find it hard to imagine.

It will unquestionably be better, yes. Because it's not going to have been prefiltered down, it'll be at the raw 1920x1080 instead of 1280x1080. And I don't know that it will have been quantized to 8 bits; it might be processed higher internally (not sure; I mean, we know that there's a 19-bit ADC in there, but I don't know what level it handles all the internal processing at). In any case, it certainly won't be worse. And since it's uncompressed HD, it won't have any DCT compression artifacting, if any is there.

So it should be cleaner, and higher res, with the potential of having less banding due to 8-bit quantization. But it won't have any higher color resolution (the component analog outputs are going to be outputting the equivalent of 4:2:2).

-- Can I get all frame rates, and all modes (e.g. 1080 Pn) from the camera when tapping the RGB out, or are there some limitations?

It only outputs 1080/60i or 720/60p. If you shoot at any different frame rates, they will be embedded into a 60i/60p signal. So 1080/24p will be output with 2:3 pulldown into a 1080/60i signal; and 720p will use frame duplication pulldown. You'll have to be able to extract that in post to use the footage at its native frame rates.

-- The AJA supposedly does its A/D conversion at "12-bit, 2x oversampling" but also seems to have 10-bit modes. Will there be a noticeable difference between a 12-bit vs 10-bit conversion?

I doubt you'll see any difference whatsoever in the HVX's output; I'm sure it isn't going to be outputting anything needing 10 bits, so 12 would be overkill. But I'd be glad to be proven wrong on that one, so if you go this route, definitely try it both ways and report back if you see any difference.

-- If we assume a theatrical screening, how much "better" would this AJA recorded footage compare to P2 footage - both at best quality?

Probably not at all.

What? Yes, I said it. We shot "Depth of Phil" on an unhacked GH1, which has the worst codec ever released on an "HD" camcorder, and projected it theatrically, and got rave reviews. The new hacked GH13 is 1,000x better. But would it have made any difference in the final image? Sure, maybe. Would anybody have cared? I doubt it.

So, yes, it's possible that you could record slightly-sharper, slightly-cleaner footage out of a KiPro. But I sincerely doubt if it's worth the hassle; DVCPRO-HD is already an excellent codec, certified Gold by DiscoveryHD for unlimited acquisition, editing, and mastering. The BBC's "Planet Earth" was shot directly to DVCPRO-HD, in the 720p mode. It's fine. If your film doesn't make it, it's not going to be because of a codec limitation.

Or a very minor improvement noticeable only to professionals who are paying very close attention?

Frankly, I think that in a properly-executed cinema presentation, you're talking about a minor improvement that's *not* noticeable to professionals, unless they're not watching your film at all and instead are watching for codec artifacts. If you post still frames at 5x magnification, I bet even your grandma will notice the difference. If you project a properly-lit, properly-scored, properly-acted, properly-directed film, nobody in the place will notice, now or ever.

-- Are there any disadvantages or dangers or quality issues that I should be aware off when attempting this?

Just the cost and hassle factors. You're making more work for yourself by using an expensive alternative recorder, and introducing cabling and portability issues.

Straight up -- if it's going to cost you extra to go this way, I wouldn't bother. Not from an HVX. If we were talking about a 2/3" Varicam, and the choice was to record to the onboard tape drive or to an external KiPro, then yeah, I'd say the KiPro is going to make the difference worth going for. But from an HVX? I think it's overkill, and that 1080p DVCPRO-HD is going to be capturing almost everything the camera is capable of delivering. And 1080p DVCPRO-HD is *much less* visibly compressed than 720p DVCPRO-HD, so you're already going to be getting the advantage of very mild compression.

I'd say save the bucks, forget the hassles, and shoot 1080/24pA.

 

[Barry_Green]

Is that signal uncompressed?

Yes.

And if recorded by the AJA, can't the 1080i60 signal be converted to a 1080 24p ProRes format?

That's a question for the AJA or Apple guys to answer. I'm pretty sure Cinema Tools could do it.

My limited understanding of the HVX is that DVCProHD essentially takes the 1080i60 signal and compresses it down onto the P2 card as 1080 24P

No, not exactly. If the camera is generating 1080/60i, it'll be saved as 1080/60i. If you put the camera in 1080/24p mode, the chip is running at 1080/24p. It will embed those 24fps into a 1080/60i signal upon recording. If you use the 1080/24pA mode (which you should ALWAYS do), then it will store frame flags in the data stream that let your NLE strip out the pulldown and give you native 1080/24p footage on your timeline.

And that the advantage of the AJA is that it can do the same thing but with much less compression.

It will, especially spatially (because it will record 1920 x 1080 instead of 1280 x 1080). But the HVX's chipset only generates about 1400 x 810 worth of resolved detail anyway, so -- the prefiltering is really no big deal. And the AJA can store higher bit depth (10-bit or even 12-bit) but if the analog output isn't delivering more than what 8 bits can handle, then the additional capability will go unused.

On a VariCam, the camera outputs 1280x720 at 10-bit, so using a KiPro would give you 33% more horizontal resolution and 4x as much color depth than the 960x720 8-bit DVCPRO-HD tape would. So in that case it makes a lot more sense. But from an HVX, I doubt you're going to get much substantial benefit from using an alternative recorder, because DVCPRO-HD pretty much takes maximum advantage of what the camera's capable of delivering.

 

[ozzymandius]

I'd say save the bucks, forget the hassles, and shoot 1080/24pA.

Wow Barry, thanks as always for the best Panny-HD tech feedback out there! I really do appreciate it.

I think you just saved me $4,500+ as it clearly doesn't make sense to go Ki Pro with an HVX. As you said, DVCProHD at 1080P should be good enough. If it was good enough for Planet Earth (still my favorite HD demo disk) then it's good enough for my film.

And btw, just saw "Depth of Phil" at the DVXUser Fest last week. I thought it was the best short there. Great acting. Great everything. And yeah, I barely noticed or cared about the codec. Congrats! :thumbsup:

 

[David Saraceno]

Wow Barry, thanks as always for the best Panny-HD tech feedback out there!

I always thought Barry should have a PayPal donation button in his signature line for some of his answers.

 

[Jarek Zabczynski]

I thought KiPro/iO HD can detect pulldown and remove it on the fly. Doesn't the Nanoflash do that as well?