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Overlook
12-01-2006, 07:14 AM
What is 4:2:2 color space and why is it good? What color space is it better than? I'm shooting a doc mostly in 720 with my HVX. Some panoramic images I think I'll shoot 1080.

How do I activate 4:2:2 or does it happen by default?

Just point me to a place to read if you like. Thanks.

Hans Moleman
12-01-2006, 07:40 AM
4:2:2 refers to the color sampling, that is; when the data is compressed, the camera scans an area for 4 luminance values, and 2 sets of color values, basically cutting your color information in half to save space without effecting the image too much.

In standard def, the color space is 4:1:1 (or 4:2:0) and in HDV its 4:2:0. you're getting (by default) twice to color information and latitude that most every other consumer and prosumer camera gets.

Capt Quirk
12-01-2006, 07:42 AM
4:2:2 colorspace is what you have before it gets compressed down to miniDV format of 4:1:1. In total layman's terms, you have more information in more bits, giving you a better image. The best images are 4:4:4 completely uncompressed, but you can't stream that very well, which is why the TV you watch is 4:1:1.

Not knowing your camera very well, I believe the only chance you have, is to capture live using the composite outputs, before it gets compressed to the tape.

Jason Ramsey
12-01-2006, 08:36 AM
The best place, would be if you have Barry's book. He describes it very well in there.

To answer your question. With the HVX, you will be getting 4:2:2 color space by default, whenever you shoot in DVCPRO50, 720, or 1080.

The 4:2:2 of the HVX means: You have 4 pixels across horizontally. The HVX will use two pixels across for each color. So, it will use different shades of a color to try to best match what it is seeing. Basically, you get two pixels for every color.
In 4:2:0 (the HDV standard, as well as the PAL mini DV standard) the camera is having to use 4 pixels per color. It uses two on one line of resolution, and then two pixels on the line below it. Basically forming a 2x2 square of pixels for each color.
4:1:1 (NTSC mini DV) uses 4 pixels in one row, per color shade. So you get a 1x4 box.

So...
for each color here's how each would handle it-
4:2:2
** (1x2 pixel box for one color)
4:2:0
**
** (2x2 pixel box for one color
4:1:1
**** (1x4 pixel box for one color)

It's not the best description, but hopefuly it makes sense to you.
The best would be 4:4:4, which would be 1 pixel per color. But don't expect to find that in any camera anywhere near the price range of the HVX. That is the creme d la creme

Hope that helped.
Jason

Capt Quirk
12-01-2006, 08:47 AM
4:4:4 is in the Varicam, Red range of camera. 4:2:2 is pretty good to work with, even if you end up compressing it down to 4:1:1 later on.

Noel Evans
12-01-2006, 09:41 AM
you're getting (by default) twice to color information and latitude that most every other consumer and prosumer camera gets.

Sorry but camera latitude has little to do with colour space and more to do with contrast ratio.

The big factor in colour space is when your doing something like compositing work, green screen etc. On a screen your eyes will never tell the difference between 4:2:0 or 4:2:2 because this is a color compression not luminence
But back to the subject.... read ramjets post... your questions are covered.

David Jimerson
12-01-2006, 10:01 AM
4:4:4 is in the Varicam, Red range of camera. 4:2:2 is pretty good to work with, even if you end up compressing it down to 4:1:1 later on.

The Varicam uses DVCPRO HD; it's 4:2:2 just like the HVX.

Capt Quirk
12-01-2006, 10:08 AM
Really? At $45k, I figured it would do 4:4:4. thanks for pointing that out.

THoff
12-01-2006, 10:12 AM
Wikipedia has a pretty good page on color sampling:

http://en.wikipedia.org/wiki/4:2:2

Noel Evans
12-01-2006, 10:36 AM
Wikipedia has a pretty good page on color sampling:

http://en.wikipedia.org/wiki/4:2:2

Everyone should read that.

Overlook
12-01-2006, 12:29 PM
Thank you all.

CacheMoneyVideo
12-01-2006, 01:32 PM
Good post. DVCPRO50 is the best for a DVD/SD project. What if i have to deliver material on DV tape? When i print to tape from a DVCPRO50 source, will it yield the same result as going to DVD?

Barry_Green
12-01-2006, 01:39 PM
Sort of. Both DV tape and DVD are going to cut the amount of color information from your DVCPRO50 source in half, but whether you're in PAL territory or NTSC territory makes a difference.

If you're in PAL territory, both DV and DVD are 4:2:0, so they'll end up looking very similar. If you're in NTSC territory, DV is 4:1:1 and DVD is 4:2:0, so they'll be different.

Jamison
12-01-2006, 02:58 PM
Wait so the V1U is using 4.2.0? since its HDV not DVCPRO HD? is that right?

David Jimerson
12-01-2006, 03:08 PM
That is correct. HDV is 4:2:0.

Sean Michael
12-01-2006, 03:11 PM
Wait so the V1U is using 4.2.0? since its HDV not DVCPRO HD? is that right?

With the V1U, I think it's possible to capture uncompressed 1920x1080 in the 4:2:2 color sample scheme via HDMI out. This is what the camera gathers prior to HDV compression.

THoff
12-01-2006, 05:10 PM
True, but it will only work for live capture in a studio setting using a Decklink card or something similar -- once it is on tape, it will have been converted to the lower color sampling. Playing back HDV from tape and then grabbing it from the HDMI port will not give you the same result.