4:4:4 10bit single CMOS HD project

[Ben Syverson]

@Juan: That's why I'm insisting that without quality lenses anything is posible, and to try to use at least SLR lenses.

My Angenieux 25mm is definitely a quality lens. I don't know why you have a bug up your a$$ about native c-mount lenses. Should we all shoot with Large Format lenses adapted to our digital SLRs? Sheesh...

You guys, I shot more tests, and I think I'm getting the hang of it. The trick is to turn the gamma all way down to 0.33 (which makes the image brighter -- it's a straight power function. Photoshop takes 1/gamma as the power function. Don't ask.), turn the brightness all the way down, and crank up the contrast until the image gets close to filling the histogram.

I tried not to overexpose any of my new shots, and it wasn't really a problem. The only shot where the sky is blown out was in a really dark little corner of the trees, so I really had to choose between blowing the sky out a little and getting detail in the shadows.

I can't respond to every question at this point, so I'll address a couple:

Juan, it's overcast in Chicago today, and earlier it was much brighter. There was no way to not blow out the sky. Now it's a little darker and I didn't have to make as many compromises.

Re: chroma. That's my new focus. If you mess with the chroma, you shouldn't see too many artifacts. It's when the luma is affected that you can see problems.

Jason: unlike your D60, I can't shoot straight linear with this camera, because it outputs 8bit. You definitely have to do as much as possible before the 10->8 conversion. It does mean a little less flexibility later than if you just dump 12bit from the sensor to your HD.

Someone asked how much the camera is. I told Sumix some people might be coming, and I worked out a slight discount from their normal price. Just mention my name and you'll get it for $1000. It comes with a tripod mount and the USB2 cable, but they said they could also throw in a C-mount adapter for certain mounts -- although they were pretty obscure mounts. ;)

I'll post some new images soon from my latest adventure taking the camera out to the lake. It was rather scary, because it kept threatening to rain. I had plastic for everything just in case, but I had to work fast. I also took stills with my Canon Elph to help in balancing the color, and figuring out how Canon interprets CCD/CMOS data.

- ben

[Jason Rodriguez]

Hey Ben,

Sounds very good. Please post some more stills, cause if this thing works, I really think I'm in. I was going to spend around $2200 on an HDCAM rental for a film I'm working on, but if I can get something like this together for around the same price, I think I'm going with this-after all, I can keep the camera later. Dynamic range and de-bayer stuff is my only consideration right now. Color can be fixed if the information is there-I have pretty good CC software.

How noisy does it get in the shadows? And do you still think it's ISO 100?

BTW, there is a lot you can do with 8-bits, I've done it with HD-CAM many times, and even DVCProHD. If you have a clean 8-bits then you're fine.

Also how easy is it to record to RAM with the software? Is the software as hard to use as X-CAP? Can the software be used with a small touch-screen (1024x768 or even 800x600), or is it hard to use, like lots of little buttons, etc.

Another thing is should a Pentium M at 1.6-1.7Ghz be enough? I guess you'd use a Mini-ITX formfactor.

BTW, you might want to try recording 10-bit linear to 8-bit log-that will keep the shadow information, and clipping highlights won't be so bad. Can you program the 10-bit to 8-bit lookup table by hand?

[Les Dit]

Ben, the images look pretty good.

I have a couple of tech questions that may allow more usability of that camera:

Can you upload arbitrary luts to the cam to make the 8 bits?
Can I do this once per frame at 24fps ? (SDK, etc ) ( Luts are Tiny )

Thanks
-Les

[Ben Syverson]

Jason,

I'd say go for it. I'm starting to get much better images. If it turns out to be a bust, you can always reschedule and shoot with something else. That's the beauty of personal projects. Let me address your other questions:


"Also how easy is it to record to RAM with the software?"

There's a button that says "record to RAM." :) I doesn't get much easier. For the keyboard-inclined, it's Shift-F4. If you want to check it out yourself, you can read the manual or even download the software at this page on Sumix.com.. It might be a bit hard to use at 1024x768 on a touchscreen, but if you talk to Sumix, maybe they'd make a touchscreen version. They've been extremely accomodating, and they're anxious to know what they can do to appeal to filmmakers. I'd say, start a conversation with them.


"Another thing is should a Pentium M at 1.6-1.7Ghz be enough? I guess you'd use a Mini-ITX formfactor."

I'm using a Pentium M at 1.6ghz. It seems to be more than enough. I was wrong about the image adjustments before -- they run in realtime. It's the histogram that sometimes slows things down. I would never use the MiniITX for this application, but whatever. It runs fine on my laptop. I'd much rather have a 14" screen to make focus adjustments than a 7 or 8" touchscreen...


"BTW, you might want to try recording 10-bit linear to 8-bit log-that will keep the shadow information, and clipping highlights won't be so bad. Can you program the 10-bit to 8-bit lookup table by hand?"

I'm going to ask them about this. I'd love to be able to define the LUT myself programmatically.


Les, I don't know why you'd want a new LUT every frame, but maybe. I'm looking into how accessible the LUT is through the SDK. Give me a day or so.

The SDK is on their website -- why not open it up and take a look at the docs? I've gotta convert some files for a while.

- ben

[Jason Rodriguez]

BTW, what's the maximum frame rate at 1280x720? Can the camera even output that frame-size (that's what it looks like you've been sending us), or do you have to crop later on?

[Juan M. M. Fiebelkorn]

Ben, I have no problems with the Angenieux lenses.
How old are they?
My problems are with crappy c-mount lenses wich are not a rare item...

BTW I'm really happy about such good news.
Nice to hear everything is going better. :)

[Jason Rodriguez]

Ben,

It looks like I can put together a fanless PC with 2.0Ghz P4, but I'm not sure that's fast enough. Maybe I can get by fanless with a 2.4Ghz P4?

Sorry for all these questions, but depending on how I think your images turn out, I think I'm gonna go for it-very exciting :-)

Oh, and I don't want to screw up, that would be a costly mistake for me, so this thing has to be useable. So I'm trying to put together a slim PC and then cobble some other stuff together like a touch screen LCD, etc. I've found some LCD's, but they were 640x480, is that too low-res?

One more biggie-what frame-rate is this thing running at exactly. In other words, when we try to sound-sync this thing, it can't be running at weird frame-rates. I'm assuming that since it's an image sequence, I can get it to go at 23.98fps just by telling the computer that's how fast it is, but I don't want video and audio going out of sync, that would be DEATH to the quality of any piece, I don't care how good the images look ;-)

[Ben Syverson]

Jason: you can shoot at almost any resolution as long as it fits in 1280x1022. The smaller the frame size, the higher the max frame rate. The frame rate depends on what Mhz the camera is running at. The higher the Mhz, the higher the frame rate, the shorter the exposure, the darker the image. 1280x720 @ 24mhz gives you just about 24fps. At 40mhz, you can get it up around 39, but I've had some issues with random row errors at 40mhz. Although now I don't see them.

I would heavily advise against P4's. I looked into them because Sumix recommends a 1.8ghz P4 or greater, but the P4 is all wrong for this. The Centrino uses less power, so your battery life is better, and at 1.6ghz, it benchmarks the same as a 2-2.4ghz P4. The P4 is hot, power-hungry, and inefficient. So there's no reason to use P4 in a laptop scenario.

Fanless is good but not necessary. My Asus M3000N hasn't kicked on the fan once since I started recording. I think you'd have a hard time finding a fanless Centrino over 1.5ghz. But maybe not -- let me know!

Re: sync. I haven't tested sync sound yet, but the frame rates are definitely not fixed. They vary from shot to shot -- I've been getting 23.5, 23.16, 23.6, etc. Is this a big deal? Absolutely, positively not.

I think it's only going to be possible to reliably record to RAM, which limits you to 30-50 seconds. How far can you go out of sync in 30 seconds? A couple of frames or so. If you average the frame rates and then slowdown/speedup all your audio, you should be able to fudge it without anyone noticing.

We're not shooting Russian Ark here. ;)

One thing that's great about this setup is its size. The 14" laptop, the camera, all my lenses (Juan, that Angenieux is probably 20 or 30 years old, btw) and the cord fit into my normal shoulder bag, and clock in at around 7 pounds. That's about how much is normally in my shoulder bag! It weighs about as much as my GL1 with the anamorphic adapter on it and the 3 hour battery.

Walking around, it feels weird to know that you have an uncompressed HD studio in your bag. It feels good. :)

I learned some valuable tips today. You can mess with the gamma via the hardware LUT, but if you drive it too hard, you'll get banding, even with 10bit. I also found out that the "gain" sliders are 100% software, not hardware. So if you up the gain, you will increase banding. I shot some good footage I won't post, because there's serious banding. However, I did get some good stuff.

Check out this shot of the lake (Computar)

Also, check out the movie! (web res)

Edit: both of these are post color-correction. Coming off the sensor, they're far more washed out.

- ben

[Jason Rodriguez]

Hey Ben,

What are you planning to do with all that moiré?

Other than that, the images look really good.

[Ben Syverson]

Jason: I don't know -- one of the pitfalls of high resolution is that you go past Nyquist, and then you start to Moiré. Canon seems to just blur the image until it's not a problem anymore. :) I'm not sure what the best thing for us to do is, but I'm open to suggestions.

I'm coding a plug-in right now to alter the chroma gains individually and shift them around. I'll post the results when they're in.

[Les Dit]

Ben,
The wave pic has some issues with a moire pattern in the pavement. If you flip through the channels, it animates in an interesting way even on the still. A slow pan on that as a movie would have been problematic.

Can you post a pan of some buildings or other vertical objects that would show how the shutter looks? The shot of the folks moving in that one shot looks good, but you really can't tell if they are 'leaning into it' of there is a shutter problem ;-)

I recommend 7 mbps Media 9 for 720P posting, it has very few artifacts and has a good compression ratio. It would also preserve moire problems.

I know what a neat feeling it is to have an HD studio in your bag! I own the little JVC HD10, and it makes very nice images, sad it has crappy exposure controls.

The HD10 had some slight scintillation effects on the 'Eagle Creek' backpack tag, but still, the detail is quite frankly amazing for what the camera is. Here is the short un color corrected wmv video:

http://s95439504.onlinehome.us/park.wmv

Resolution wise, none of the CMOS 1.3 cameras looks anywhere near that sharp. not even close.
It's obvious JVC has a kick ass demosaiker. Plus they are compressing it to a 19 megabit tape stream, all fits in your hand!

It's fun to use the JVC as a poor mans HD benchmark!

-Les

[Ben Syverson]

Les, if you read the posts right before yours, you'll see we're well aware of the moiré. In fact, it's a good thing, because it tells us we're at/past Nyquist for the lens/sensor combination. I don't know what strategies the major manufacturers use to combat moire, but my guess is that they blur the image, and then sharpen it.

The HD10 is nice, but it way oversharpens everything, which is a dealbreaker for me. That's part of what gives the HD10 that "video" look. Nothing coming off the Sumix camera looks like video. And I hate to argue with your assertion about sharpness, but I think these CMOS cameras have the upper hand. My camera is rendering 1x1 pixel details. You literally cannot get sharper than that. In fact, you don't want to be that sharp, because that gets you into problems with aliasing and moiré as you brought up.

Check this image out. This is pre-color correction, and one of the images that is impossible to correct fully. I've since learned a lot about how far you can push the on-board 10->8bit downsampler.

-ben

[Les Dit]

Ben,
Yes, I see we had a burst of posts there! I missed them.

While I think that the HD10 still might be a bit crisp, it doesn't do that much ringing on the edges, like the poor HD1 does. One thing that I have noticed is that people who work a lot with DV footage ( what I call web cam res ) tend to be a little taken back by the HD10, they are not used to seeing every hair on someones head.
As long as there is minimal edge ringing, you can always soften or diffuse shots in post. But on the HD1, the ringing is horrible, nothing can be done. HD10 ain't so bad.
When I first saw frames from my HD10, it reminded me more of scanned film than DV, just sharpness wise, ignoring grain. I'm way more used to seeing scanned film than DV. Maybe it's psychological.
Perhaps we can shoot a standard res chart ( A fresh $1 bill ) and then see what's going on with the various cameras ?


Did you recently look at the footage I posted? Can Mac's play it OK? I'm not sure if Mac people can see it.
Well, back to the garage.... I'm finishing my GG orbitor for DOF tests on the HD10.
-Les

[Ben Syverson]

Les,

WM9 footage plays back extremely slow on my system, like 1fps -- but maybe that's because it's a 867mhz G4 Powerbook. That's partially why I'm hesitant to encode to WM9...

- ben

[Jason Rodriguez]

You can't encode to WMV9 on a Mac right now Ben.

BTW, all those moire problems I'm seeing should be fixed by an optical low-pass filter like what we were talking about.

One thing I'm wondering though,

Were's the color??

The color-corrected version of this that I have reminds me of faded film from the 70's! I know there must be some green in those trees!

edit: I was just thinking to myself-yes, this does look like film, just not stuff from the 90's ;-)

BTW, Ben, that clip you showed of people walking around, that seemed to have okay saturation, at least something to work with.