"Grid" look when shooting in DV mode at DVinfo.net

Chris Davis · July 29th, 2009, 08:58 AM

I just shot some footage yesterday with my HD100U in DV mode. When I started working on it today I noticed a blocky grid type look to most of the footage. It's hard to see on still images, but here's a good example:

Full size:
http://www.famousdavispro.com/images/badhat.jpg

Detail:
http://www.famousdavispro.com/images/badhatdetail.jpg

Now it's only more noticeable on the red hat, but it appears to be on all the footage, regardless of subject. Is this a problem with the camera, the lens, the tape stock (Sony DVM60), or what?

Perrone Ford · July 29th, 2009, 09:20 AM

It's a problem with shooting DV, and even more a problem with you over saturating the colors in DV.

Tim Dashwood · July 29th, 2009, 01:39 PM

4:1:1 chroma subsampling is used with DV. It basically means that your luminance is 720x480, but your chroma sampling is 180 x 480. (Can someone please check my math.)

Shaun Roemich · July 29th, 2009, 05:38 PM

Tim is right and his math is good.

And so is Perrone.

Marc Colemont · August 4th, 2009, 02:58 PM

I never shoot in DV, unless the client wants DV tapes to take with him at the location.
I prefer to shoot in HD, Edit in HD and only after the final edit, only then to convert to what is needed to preserve the highest quality at the end.
Computers now-a-days can handle the HD pretty good as if you are editing DV years ago on a Pentium.

Leonard Levy · August 4th, 2009, 10:14 PM

That doesn't look like normal DV artifacting to me. It looks much worse. I don't know this camera so it is possible that it is not optimized for SD. That is the case for example with the HVX200 which has awful stair step aliasing in SD, much worse than a DVX100.
Whatever the cause, it is not acceptable DV in my opinion though.

Tim Dashwood · August 5th, 2009, 08:44 AM

That's actually pretty normal looking DV encoding for an edge of pure red or pure blue. It would look the same with the DVX100.

July 29th, 2009, 08:58 AM	#1
Chris Davis Trustee Join Date: Jul 2005 Location: Willmar, MN Posts: 1,400	"Grid" look when shooting in DV mode I just shot some footage yesterday with my HD100U in DV mode. When I started working on it today I noticed a blocky grid type look to most of the footage. It's hard to see on still images, but here's a good example: Full size: http://www.famousdavispro.com/images/badhat.jpg Detail: http://www.famousdavispro.com/images/badhatdetail.jpg Now it's only more noticeable on the red hat, but it appears to be on all the footage, regardless of subject. Is this a problem with the camera, the lens, the tape stock (Sony DVM60), or what?

July 29th, 2009, 09:20 AM	#2
Perrone Ford Inner Circle Join Date: Nov 2006 Location: Tallahassee, FL Posts: 4,100	It's a problem with shooting DV, and even more a problem with you over saturating the colors in DV. __________________ DVX100, PMW-EX1, Canon 550D, FigRig, Dell Octocore, Avid MC4/5, MB Looks, RedCineX, Matrox MX02 mini, GTech RAID, Edirol R-4, Senn. G2 Evo, Countryman, Moles and Lowels.

July 29th, 2009, 01:39 PM	#3
Tim Dashwood Wrangler Join Date: Aug 2005 Location: Toronto, ON, Canada Posts: 3,637	4:1:1 chroma subsampling is used with DV. It basically means that your luminance is 720x480, but your chroma sampling is 180 x 480. (Can someone please check my math.) __________________ Tim Dashwood

July 29th, 2009, 05:38 PM	#4
Shaun Roemich Inner Circle Join Date: Sep 2002 Location: Vancouver, British Columbia (formerly Winnipeg, Manitoba) Canada Posts: 4,088	Tim is right and his math is good. And so is Perrone. __________________ Shaun C. Roemich Road Dog Media - Vancouver, BC - Videographer - Webcaster www.roaddogmedia.ca Blog: http://roaddogmedia.wordpress.com/

August 4th, 2009, 02:58 PM	#5
Marc Colemont Major Player Join Date: Nov 2005 Location: Belgium Posts: 695	I never shoot in DV, unless the client wants DV tapes to take with him at the location. I prefer to shoot in HD, Edit in HD and only after the final edit, only then to convert to what is needed to preserve the highest quality at the end. Computers now-a-days can handle the HD pretty good as if you are editing DV years ago on a Pentium. __________________ Marc Colemont - Belgium - http://www.mc-productions.be JVC GY-HM850's, HM890, HM600

August 4th, 2009, 10:14 PM	#6
Leonard Levy Trustee Join Date: Feb 2006 Location: USA Posts: 1,684	That doesn't look like normal DV artifacting to me. It looks much worse. I don't know this camera so it is possible that it is not optimized for SD. That is the case for example with the HVX200 which has awful stair step aliasing in SD, much worse than a DVX100. Whatever the cause, it is not acceptable DV in my opinion though.

August 5th, 2009, 08:44 AM	#7
Tim Dashwood Wrangler Join Date: Aug 2005 Location: Toronto, ON, Canada Posts: 3,637	That's actually pretty normal looking DV encoding for an edge of pure red or pure blue. It would look the same with the DVX100. __________________ Tim Dashwood