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Greenscreen and mini dv question [Archive] - IndieTalk - Indie Film Forum




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clive
06-26-2006, 05:15 PM
Hi Guys

Someone threw a tech question at me today and I didn't have an answer.

Basically they'd been told that mini-dv doesn't handle green screen very well and that they'd be better going HD for a project they had in mind. They wanted to know what I thought.

This had come to them from a few different sources all of whom had bad mini-dv green screen experiences to relate.

So what's the deal here -- are minidv and green screen a bad combination or are the bad results because of poor technique?

Information based on experience is my preference here.

Ta in advance.

Shaw
06-26-2006, 07:04 PM
Both. Shooting on a better format like Digibeta, DVCpro50, HD (not HDV) would provide better results. That said, it certainly CAN be done with DV footage. You just have to have good technique and then find someone familiar with keying DV footage.

What is the project for? DV keys are acceptable for applications but not others. If their budget allows certainly shoot on a better format. If not - it can still be done. It will just take more work and won't look quite as nice (but perfectly acceptable for many applications).

knightly
06-26-2006, 07:08 PM
They're fine so long as you light carefully. Throw a yellow hairlight on them to help the key separate the subject from the background, shallow DoF to smooth out the screen, enough distance between the subject and backdrop to prevent the green from spilling onto the subject...light the screen evenly.

dylan61
06-26-2006, 10:41 PM
miniDV is serviceable for green screen and can be done if done correctly (see Knightly's post), but it will never look as good as green screen done correctly on HD or film due to the fact that miniDV automatically creates a compressed video file. We've done green screen work with our XL2, but have agreed that if it comes to a client that demands something excellent, we'll ask them for more money to do it on a higher quality format.

Wether you have someone who is great at green screen, someone who is ok or someone who is bad, they will all do better with higher quality, uncompressed video. I guess the question is, what's the desired outcome and what's the budget? Are you projecting it on a big screen or watching it on the internet? The smaller the final image, the less noticeable the imperfections of miniDV will be.

clive
06-27-2006, 01:43 AM
Thanks guys, this is the info I needed.

It's a music video project, which has to go to MTV, so I think he'll need to look at stepping up.

I figured it was a compression problem, but didn't want to go shooting my mouth off about something I wasn't completely sure about. Which in itself is strange :lol:

sonnyboo
06-27-2006, 08:23 AM
The biggest thign to remember along with compression (meaning less detail) with Mini DV is also the limited color space (4:1:1) so that in the crucial area of color extraction (aka keying or green screen), you have a lot less detail to work with.

What it comes down to in the simplest terms, Mini DV has very few pixels and color space to work in, so extracting a sharp image from a green screen is not optimal (and that's being kind). HD has a much broader color space and a LOT more pixels to work from. Extraction will definatley be better on true HD.

Mini DV - 720x480 (in PAL 720x576)) - 4:1:1 color space

HD - 1920x1080 - 4:4:4 color space *

* depending on make & model of camera, some are 1280x720 and 4:2:2 color space, but that's still exponentially better than Mini DV

clive
06-27-2006, 03:28 PM
Thanks for all the info -- he's arranged to go Digibeta, which I think was a excellent choice.

sonnyboo
06-28-2006, 09:09 AM
DigiBeta is a 4:4:4 color space at 720x480 UNCOMPRESSED - it will be incredibly better to extract the matte with that.

clive
06-28-2006, 01:14 PM
Yeap, that's why it's the SD master format of choice. It's the very colour staturation that drives me nuts in most shooting environments, that works so well in this instance.

Alphie
06-28-2006, 09:42 PM
There is some pretty clever green screen with Mini-DV in this Chamber of Commerce video I produced two years ago. Enjoy!

http://www.harkproductions.com/media/video/chartthecourse.wmv

Spatula
06-28-2006, 10:06 PM
There is some pretty clever green screen with Mini-DV in this Chamber of Commerce video I produced two years ago. Enjoy!

http://www.harkproductions.com/media/video/chartthecourse.wmv

Oh man- that was brilliant!!! Great video with some neat effects. Totally hilarious!