Keylight DVCPro HD vs 1080
by Scott Skaja
on
Jul 7, 2008 at 1:00:25 pm
I'm embarking on a green screen compositing project using Keylight in AE. My client has an option of shooting DVCPro HD or 1080. My instincts tell me it we will have a easier time keying shooting at 1080. Two questions...
Do you agree that 1080 is a better way to go?
And if so, do you recommend shooting 1080p or 1080i?
Scott Skaja
edit/design/animation
www.scottskaja.com
Re: Keylight DVCPro HD vs 1080 by Joey Foreman on Jul 7, 2008 at 1:42:02 pm
DVCPro and 1080 are not mutually exclusive categories. DVCPro HD is a codec that can carry streams of 720p or 1080i. Or 1080p, which would be your best choice for greenscreen. Some cameras, like the HVX200, use an implementation of 1080i, 24 or 30p.
For close ups and medium shots 720p is adequate, but if you're going for full body shots you'll need the extra resolution of 1080 to preserve as much facial detail as possible. And a really good lens.
Another tip - i assume you're shooting with an HVX or HPX - avoid the cine gamma settings like the plague for this type of shooting.
Joey Foreman
Editor/Animator
Nowhere Productions, Athens, GA
Re: Keylight DVCPro HD vs 1080 by Scott Skaja on Jul 7, 2008 at 2:38:09 pm
Joey,
Thanks for the info, very helpful. Please expand on the cine gamma topic, I'll be meeting with the DP today and I want to be able to back up my reasoning for not using the cine gamma.
Scott
Scott Skaja
edit/design/animation
www.scottskaja.com
Re: Keylight DVCPro HD vs 1080 by Joey Foreman on Jul 7, 2008 at 2:53:04 pm
Basically it adds too much sharpening and crushes the blacks.
The sharpening leaves a lot of hard to clean up artifacting and the crushed blacks leave dark edge halo-ing and make stray shadows harder to key out. It's also really contrasty which makes color correction/enhancement harder, and it's noisy. The HVX is a very noisy (grainy) camera in general, and Keylight's automatic spill suppression really brings out the sizzle. But there are techniques to deal with that.
I don't know what sort of lighting configuration you'll have but if you're using Kinos the Fluo setting works very well.
Joey Foreman
Editor/Animator
Nowhere Productions, Athens, GA
Re: Keylight DVCPro HD vs 1080 by Scott Skaja on Jul 7, 2008 at 3:02:39 pm
The lighting scheme has yet to be determined, so your recommendation on using Kinos is helpful. When you mentioned the Fluo setting, I assume that's a preset in Keylight, or is it something on the actual light itself?
As far as the background color, do you know if there certain color specs that The Foundry/Keylight recommends?
Scott Skaja
edit/design/animation
www.scottskaja.com
Re: Keylight DVCPro HD vs 1080 by Joey Foreman on Jul 7, 2008 at 3:27:47 pm
Neither, it's a preset on the HVX. The green needs to be pure and manufactured specifically for this type of work. Rosco is a good brand. There are tons of resources for greenscreen basics on the web. I hope your DP has some experience in this area.
Joey Foreman
Editor/Animator
Nowhere Productions, Athens, GA
Re: Keylight DVCPro HD vs 1080 by Steve Oglesby on Jul 7, 2008 at 5:00:09 pm
I do not disagree with any of the comments, so far, but would add that along with avoiding altering the gamma curve, you should also use all the straight video setting for the HVX. The HVX is noisier than, say, a Varicam, but I have had no trouble keying any HVX 720p HD footage in AE Keylight 1.2. No edge crawl, or glistening hair friz. Remember, the HVX uses 1/2" chips, and an odd pixel configuration to achieve HD, so pushing it to do 1080 is also amplifying the noise.
Recommend using 720/60p. This will give you denser picture info for the keyer to see, but will burn through media at twice the rate of a 30p native recording mode. (-2) detail will help with edge blending and light wrapping. Full body shots biggest problems are the typical areas of lighting where the hardest shadows of feet meet the floor. Recommend "Space Lights" for the entire set, then punch in modeling lights for faces only. Expose the screen one stop under the foreground faces. Rim light, Rim light, Rim light.
When you get to post try to stay away from the Screen Strength control in Keylight.
Re: Keylight DVCPro HD vs 1080 by Jim Dodson on Aug 7, 2008 at 2:42:19 am
Scott,
If you do use the HVX ( as a previous poster mentioned) the footage will be noisy!! (It might be noisy regardless of the camera or resolution shot, so....
I had incredible luck using temporal noise reduction:
Adding the "remove grain" filter to your compressed footage will be a great help in reducing noisey keys -- make sure you use "temporal filtering" as follows (from AE 7 help):
To add temporal filtering to a sequence
Apply the Remove Grain effect to your image.
Place the Remove Grain preview region over the area of the image that has the most subtle changes from frame to frame or that has the most moving image detail.
Select Enable in the Temporal Filtering controls.
Adjust the Amount value to 100%.
Create a RAM preview of the sequence or render it.
If you see unwanted streaking or blurs around moving objects, reduce the Motion Sensitivity value, and then preview or render it again.
Try the following techniques if you want to improve the results:
To quickly reduce the noise of a sequence that has a lot of buzzing noise, set the Noise Reduction value to zero and the Temporal Filtering Amount to 100%, and render the sequence.
To speed up previews, apply temporal filtering to your sequence after all the settings for a single frame have been adjusted.
