Camcorder quality?

[hiphopcr]

You should check out Aruna's tip on matching grain, unless you add a bit of grain onto your CG images they will always looks fake... way too clean and crisp.

As for making your camcorder footage look better, you might check out Magic Bullet for After Effects or Natress for Final Cut... I've never used them, and I've heard mixed reviews, who knows?

[bartrobinson]

Well, I will assume you are shooting with DV, if otherwise let me know. First, your CG is probably too crisp. It could probably use a small blur. It also likely doesn't have any video noise, so you should get some animated noise and layer that over your cg only, not the background live action footage. Obviously make sure it matches the noise produced by the camera. It might be best to shoot some video of a 50% gray surface with EVEN lighting, or at least a white wall, and process a clip of the noise into something you can use to apply noise to your cg. Do this obviously after you have applied the blur. You might also run your cg footage though virtual 4:1:1 or 4:2:0 image compression to simulate DV color artifacts. You can do this by splitting the image into it's luma and chroma components and then scaling the chroma components down as suggested by the compression techniques of your dv spec (NTSC or PAL) or simply render it to an animation using your DV codec. I think you should also NTSC / PAL broadcast limit your colors for the CG, in other words nothing below 16 or above 235 in RGB. Of course, you will want your cg to be interlaced if your live action is interlaced. Make sure it uses the same field order/dominance.

[IestynRoberts]

Hello guys, many thanks for replying.

Hiphopcr: I've looked everywhere for Aruna's tip on matching grain, but i can't seem to come across anything. Is it possible you could send me the link? Thanks for the Magic Bullet for After Effects tip, i'll keep a look out for it.

Bart: Thanks for the in-detail post. However, im not much of a pro on the camcorder front. so i have no idea if im using a DV camcorder. How would you go about' processing a clip of the noise from the camera into something you can use to apply noise to your cg' . Im a bit lost on splitting the image into it's luma and chroma components and then scaling the chroma components down as suggested by the compression techniques of your dv spec (which is PAL). However, i will try and follow as closley as i can when i go home tonight. If you have any tutorials that u know of, please let me know.
Thanks
Iest

[Hugh]

Iest - here's Aruna's tip:

http://www.digitalgypsy.com/vfxlog/archives/2005/01/tip_of_the_week_3.php. He's got a lot of great stuff on his blog (http://www.digitalgypsy.com/vfxlog/) - including quite a number of tips-of-the-week (http://www.digitalgypsy.com/vfxlog/archives/tip_of_the_week/index.php)

[IestynRoberts]

Hey Hugh, excellent, thank you very much. Looks like a very promising site.

Thanks
Iest

[bartrobinson]

Hello guys, many thanks for replying.
Bart: Thanks for the in-detail post. However, im not much of a pro on the camcorder front. so i have no idea if im using a DV camcorder.

Are you saying you didn't shoot the footage yourself, or you just don't know what kind of camcorder you are using? Did you capture the footage yourself? If so, did you use firewire or USB connections or did you capture over an RCA or BNC video cable? What model / brand is the camcorder?


How would you go about processing a clip of the noise from the camera into something you can use to apply noise to your cg.


Well, generally when I shoot noise to composite over CG for use in Adobe After Effects or something like that, I want my video clip of noise to be over a perfect 50% gray color. That way you can apply it with the overlay mode and the gray goes away and the noise stays. The problem is, when you shoot 50% gray with a camera, it's pretty much never perfectly 50% gray because of lighting and white balance and stuff. So, you have to color correct it to be as close as possible. You would also likely use the matte that you are using to composite your cg onto your live action to also composite the noise clip onto only your cg.


Im a bit lost on splitting the image into it's luma and chroma components and then scaling the chroma components down as suggested by the compression techniques of your dv spec (which is PAL).
Iest

Well, explaining all this is a bit beyond this forum, but I'll just say, you want your cg to look like your live action footage, right? So whatever compression or color subsampling has been applied to whatever video format your live action footage is in, you want to have the same thing applied to your cg so that it "fits in". If your live action is in PAL DV, then you want to compress your cg with the same PAL DV codec or at least degrade the quality of your cg in a similar way.

[IestynRoberts]

Hello there Bart, thanks for repying.

My freind shot the film, we used a Panasonic camcorder of some sort, and used to Firewire to caputuer it into the PC. Sorry i dont have camcorder with me at the mo so i dont quite know the specs.
As for filming the noise, would you just film a slightly off white wall for instance, and then overlay that over the cg footage? Blend it, or make it transparent so i can see the CG behind it? Coz chances are, it's not gonna have an alpha layer on the wall is it?
Did u teach yourself or got some tutorails or something on dowing this? This seems to be harder than i thought it would be.
Thanks
Iest

[bartrobinson]

Hello there Bart, thanks for repying.

My freind shot the film, we used a Panasonic camcorder of some sort, and used to Firewire to caputuer it into the PC. Sorry i dont have camcorder with me at the mo so i dont quite know the specs.

Ok that pretty much answers it. If the footage was transfered via firewire, you were VERY likely using a DV camera.


As for filming the noise, would you just film a slightly off white wall for instance, and then overlay that over the cg footage? Blend it, or make it transparent so i can see the CG behind it? Coz chances are, it's not gonna have an alpha layer on the wall is it?

A white wall may work, but you could also loose a portion of the noise if the camera automatically adjusts the wall to look white and then brightens the image too much.

Someone else speak up here, let us know what works for you. No, of course the noise clip will not have an alpha channel. If the clip is very close to white you could probably get away with multiplying it over your cg element, of course using the alpha channel of the cg element to hold out the noise from the live action. If the noise clip was near black you might be able to get away with adding or screening it over your cg. You also want to follow the general way that grain or noise appears over on footage: the darker the area the more grain or noise there is, the lighter the area the less grain or noise appears. So, in addition to holding out the noise from the live action using the cg elements alpha channel you may also want to use an inverted version of the luminance or brightness of the cg element as an alpha channel for the noise layer.

Check out these threads for a little more talk on the subject.

http://www.cgtalk.com/showthread.php?t=128852&highlight=noise
http://www.cgtalk.com/showthread.php?t=78880&highlight=noise


Did u teach yourself or got some tutorails or something on dowing this? This seems to be harder than i thought it would be.
Thanks
Iest

Well, talk to they guys here, cause there is a ton of professional knowledge around here. Also, read The Art and Science of Digital Compositing book: http://www.amazon.com/exec/obidos/ASIN/0121339602/qid=1119034270/sr=2-1/ref=pd_bbs_b_2_1/102-0230991-6877753

It's basically the compositing bible.

[IestynRoberts]

Hi Bart, thank you very much for your help, i've just got back after the weekend so i have'nt had a chance to try it yet, but never the less i'll give it a whirl later on, and i will come back to you.
Many thanks for the links!
Iest

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