OT: DV chromakey quality

riredale wrote on 3/11/2005, 1:09 PM
Just stumbled across a website I'd seen in the past. It's getting a bit long in the tooth in some aspects, but since there have been some chromakey threads on this board recently, I thought I'd once again mention that it shows DV to be pretty darn good in this respect:

"...it's reasonably safe to say that the spatial uncertainty when using green as the key color is only about 30 percent greater (2.000/1.587 = 1.3) than that of 4:2:2 D-1 and, based on comparative chroma bandwidth, is likely to be about the same as that for Betacam SP..."

The important thing is to use green as the key.

Comments

Coursedesign wrote on 3/11/2005, 1:53 PM
Whoa!

That article contains a number of errors and misunderstandings, beginning with the priceless "if broadcasting less than 483 active lines was illegal, all U.S. stations transmitting letterboxed movies would have by now lost their licenses."

Apparently he thinks that black lines at the top and bottom don't count, and even worse is that he doesn't know what the extra 6 lines (not 3) do.

It's been my own experience, and the experience of 100% of working professionals I have talked to, that it is quite a bit easier and quicker to pull chromakeys with 4:2:2 (D-1, D-5, DV50, etc.) than with 4:1:1 DV25 footage.

Of course you can get a good end result most or nearly all of the time with DV25.

It's just a lot more work, unless you have a very simple foreground. Not 30% more work but "lots more." Of course if you are OK with keys that look like cardboard cutouts, then there is is no difference at all (other than the substantial general quality improvement with 4:2:2).

Theory is nice, but sometimes you have to verify what happens in practice.