Which is better 4:1:1 or 4:2:0? at DVinfo.net

Go Back   DV Info Net > The Tools of DV and HD Production > Open DV Discussion

Open DV Discussion
For topics which don't fit into any of the other categories.


Reply
 
Thread Tools Search this Thread
Old May 25th, 2006, 11:34 AM   #1
Major Player
 
Join Date: Jan 2003
Location: Detroit MI
Posts: 253
Which is better 4:1:1 or 4:2:0?

Please help me understand. Which is better 4:1:1 or 4:2:0?
I know NTSC dv uses 4:1:1 AND PAL dv uses 4:2:0. I have also heard the new AVCHD uses 4:2:0.
__________________
ScapeFilms.com | My Photography | IMDB Profile
Mike Tesh is offline   Reply With Quote
Old May 25th, 2006, 12:30 PM   #2
Major Player
 
Join Date: Sep 2004
Location: Phoenix, AZ
Posts: 493
They both subsample the color channels 4:1, just in different patterns. I think in general 4:2:0 will be more pleasing, since it's equally inaccurate in H and V directions.

MPEG-2 also uses 4:2:0, so NTSC DVD's are 4:2:0 as well. Which means that 4:1:1 shot footage converted to MPEG-2 is sort of taking one problem and massaging it into another problem.
__________________
Owner/Operator, 727 Records
Co-Founder, Matter of Chance Productions
Blogger, Try Avoidance
Joshua Provost is offline   Reply With Quote
Old May 25th, 2006, 02:29 PM   #3
Major Player
 
Join Date: Mar 2004
Location: Portland, OR
Posts: 314
Quote:
Originally Posted by Joshua Provost
I think in general 4:2:0 will be more pleasing, since it's equally inaccurate in H and V directions.
Adam Wilt seems to disagree (at least as far as multigeneration work in 4:2:0 vs. 4:1:1):

"The theory here is that by evenly subsampling chroma in both H and V dimensions, you get a better image than the seemingly unbalanced 4:1:1, where the vertical color resolution appears to be four times the horizontal color resolution. Alas, it ain't so: while 4:2:0 works well with PAL and SECAM color encoding and broadcasting, interlace already diminishes vertical resolution, and the heavy filtering needed to properly process 4:2:0 images causes noticeable losses; as a result, multigeneration work in 4:2:0 is much more subject to visible degradation than multigeneration work in 4:1:1."

http://www.adamwilt.com/DV-FAQ-tech.html#colorSampling
John McManimie is offline   Reply With Quote
Old May 25th, 2006, 02:56 PM   #4
Trustee
 
Join Date: Mar 2004
Location: Milwaukee, WI
Posts: 1,719
As Joshua pointed out 4:1:1 is a pain for DVD's.

4:1:1 encoded to a DVD becomes 4:1:0 which is disgusting chroma. This is because with 4:1:1 every line has a new sample 4 pixels wide. Every line however does have a new value of chroma. 4:2:0 on the other hand alternates every other line. So when you encode 4:1:1 video to a 4:2:0 DVD every other line throws out the chroma information making it a 4:1:0.

It is true however that interlace does not do as well with 4:2:0. It is hard to have an interlaced source use a block that is 2x2 pixels in size since every other line is actually a new moment in time. With progressive video 4:2:0 is far superior.

If you do not plan on rendering multiple generations of your 4:2:0 source then you shouldn't have anything to worry about. If you do need to do some heavy effects work use a different format such as uncompressed. You will not gain any chroma detail but you also will not loose any with multiple generations of 4:2:0.

If second generation means encoding to DVD then the slight loss from 4:2:0 will be much much less then the loss of dropping down to 4:1:0.

This is yet another reason why 4:2:2 is better and not just for keying. 4:2:2 allows you to go in any direction in terms of format or compression without any loss beyond the limits of that format.

Besides 4:1:1 is kind of a dead format if you think about it. Really the only thing in the world that uses 4:1:1 is NTSC DV. PAL DV, digital broadcasts, both flavors of HDV, DVD and pretty much every internet format all use 4:2:0.
Thomas Smet is offline   Reply With Quote
Old May 25th, 2006, 02:57 PM   #5
Major Player
 
Join Date: Sep 2004
Location: Phoenix, AZ
Posts: 493
John,

I certainly won't disagree with Adam, but his point is about multi-generational use.

From a pure format perspective, if you take a 4:4:4 image and convert to 4:1:1 and 4:2:0, the 4:2:0 is more pleasing, in my opinion. If your destination is MPEG-2, 4:2:0 is a theoretically better acquisition format, since the color space is the same.

Josh
__________________
Owner/Operator, 727 Records
Co-Founder, Matter of Chance Productions
Blogger, Try Avoidance
Joshua Provost is offline   Reply With Quote
Old May 25th, 2006, 03:03 PM   #6
Major Player
 
Join Date: Mar 2004
Location: Portland, OR
Posts: 314
Quote:
Originally Posted by Joshua Provost
John,

I certainly won't disagree with Adam, but his point is about multi-generational use.

From a pure format perspective, if you take a 4:4:4 image and convert to 4:1:1 and 4:2:0, the 4:2:0 is more pleasing, in my opinion. If your destination is MPEG-2, 4:2:0 is a theoretically better acquisition format, since the color space is the same.

Josh

I agree with you. I was just offering additional information for Mike Tesh since he didn't indicate much in his question, "Which is better 4:1:1 or 4:2:0?".
John McManimie is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

Professional Video
(800) 833-4801
Portland, OR

B&H Photo Video
(866) 521-7381
New York, NY

Z.G.C.
(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

Precision Camera
(800) 677-1023
Austin, TX

DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > The Tools of DV and HD Production > Open DV Discussion

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 03:28 AM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2017 The Digital Video Information Network