Comments

taliesin wrote on 9/11/2002, 6:10 PM
Well, there is a difference. Most noticable at sharp color edges or after color-keying.

A big difference? - This is very individual impression.

Furthermore - if you gonna use a high-end Betacam, there are some advantages in quality on the one hand but some disadvantages in quality on the other hand.
And if you plan to capture the Beta-stuff into a dv-system - you'll combine both of the DISadvantages.

Marco
SonyEPM wrote on 9/12/2002, 8:38 AM
A Dbeta deck/camera/scope/raid/capture card setup is going to run you about 100 grand- if that makes any difference.
kkolbo wrote on 9/12/2002, 9:34 AM
Digi Beta loaded to a DV 4:1:1 system is no way to go. If you run 4:2:2 from beginning to end there is a difference. I can clearly see it in the end product.

How much that difference is, is based on your eyes an opinion. While I can see it clearly, I have put stuff in front of consumers and they can't pick the differnece. While I love the 4:2:2, I produce 4:1:1 DVCAM because the end viewer can seldom tell the difference and the cost difference is major.

K
dsanders wrote on 9/12/2002, 11:08 AM
Ahh.... What is 4:2:2 and 4:1:1? I've seen it all over the place but don't know what it is.
riredale wrote on 9/12/2002, 11:36 AM
Very briefly, here's what this stuff means...

The human eye is much less able to pick out "sharpness" in colored borders than in gray borders (remember the business about rods and cones in the eye?). TV engineers long ago figured out that they could thus save a lot of bandwidth by taking the raw RGB pixel data and massaging it into a new form--a luminance (b&w) channel and two color channels. The two color channels could be massaged to derive the third color, so the third color information didn't have to be sent separately.

Then the engineers took advantage of the eye's lack of color sharpness sensitivity by reducing the number of samples of the color channels. The shorthand way they write this is to say something like "4:4:4" where the first figure is the relative sampling rate of the luminance (Y), and the second and third figures represent the color sampling rates. Conventional practice in the broadcast world is to use 4:2:2, which means the color is about half as sharp in the horizontal direction as luminance. DV uses 4:1:1, so the color sharpness is one-fourth as sharp. Amazingly, it's not that easy to tell the difference, but it makes a BIG difference for green-screen compositing, where the keying is determined by the fuzzy color information.

DVD, by the way, uses a different sampling rate--4:2:0. This is an illogical nomenclature; what is really happening is that chroma is sampled at one-half the luma rate horizontally AND one-half vertically.

Anyway, the bottom line is that DV is great for most stuff, but if you really need perfection then only 4:4:4 will do.

Here is an excellent web page that goes further into this topic:

http://www.adamwilt.com/DV-FAQ-tech.html#color_sampling
asafb wrote on 9/12/2002, 10:37 PM
So if i spend $100,000 on the whole digibeta spiel, it would be sdi in right? and it would be an avi files correct?
asafb wrote on 9/12/2002, 10:39 PM
Finally, one more question:

What does Hollywood use for its featuretts? (like the making of.)) i notice it is in video mode, not using 35mm cameras, and always 4:3. What do they use? Digibeta?

Tyler.Durden wrote on 9/13/2002, 6:41 AM
Hi asafb,

FWIW, The whole digibeta spiel could cost you a lot more than 100K...

The advantage of digibeta is very light compression. So if you wish to remain "uncompressed" throughout the process, the equipment involved gets pretty pricey.

You would likely digitize digibeta via SDI, the file format could be a number of choices, depending on the type of compression you desire. If you convert to DV, you will enjoy 5:1 compression sampled at 4:1:1 (in NTSC).


As for "making-of" docs... they use whatever the budget allows.


HTH, MPH

John_Beech wrote on 9/13/2002, 10:22 AM
SonicEPM, you crack me up . . . and beat me to the punch at the same time!