HDV deinterlacing and color space at DVinfo.net

Aaron Shaw · March 15th, 2005, 07:06 PM

Hey guys,

This is a question that came up on a forum elsewhere and I figured I would post it here in hopes of finding out more. I understand the technical aspects of the HDV format rather well. No problems there but this one stumped me.

Hoe does the Sony FX1/Z1 deinterlace in camera? I ask because I am curious what affect this has on the 4:2:0 color space. Anyone know?

Douglas Spotted Eagle · March 15th, 2005, 07:27 PM

I'm not sure why someone would ask that question.
4:2:0, 4:2:2, 4:1:1, or whatever other luma/chroma sampling scheme used isn't related to interlaced or non-interlaced, or deinterlaced. you can have any flavor of the above in p-scan or interlaced or deinterlaced.

Aaron Shaw · March 15th, 2005, 07:55 PM

Yes I know. I'm just curious how the deinterlacing handles the chroma from the two fields when blending them. Is there a loss of chroma (ie less than 4:2:0), is there a gain, nothing?

For instance, when down converting you can get full chroma by throwing out one of the fields. While this isn't the same thing, I do wonder what effect the field blending has on the color per any given area.

Douglas Spotted Eagle · March 15th, 2005, 08:10 PM

I just did a test, you can easily repeat.
Shoot colorbars or something of mixed colors. (I used a color chart)
Shoot all modes.
Capture.
Grab stills of all modes.
drop stills into Photoshop.
Use the eyedropper, compare colors.
you'll not find differences between the two modes.
In fact, deinterlace in your app, and do the same thing.

The only thing you should see is some loss in sharpness.

Joe Carney · March 16th, 2005, 02:10 PM

Spot, just a thought, has anyone tested these new cameras against highly contrasting plaids and polka dots (the bane of dv25)?

Douglas Spotted Eagle · March 16th, 2005, 03:13 PM

Polka dots yes, plaids...no. I don't have any, and frankly hadn't considered it. On my way to Walmart....I'll report back later.

Andre De Clercq · March 18th, 2005, 10:41 AM

Sampling raster doesn't affect colorspace properties in terms of color rendition. There is however a known issue (the "chromabug") when 4:2:0 footage needs to be deinterlaced. Maybe the artifacts are less visible in HDV than they are in SDDV

March 15th, 2005, 07:06 PM	#1
Aaron Shaw Major Player Join Date: Jul 2004 Posts: 587	HDV deinterlacing and color space Hey guys, This is a question that came up on a forum elsewhere and I figured I would post it here in hopes of finding out more. I understand the technical aspects of the HDV format rather well. No problems there but this one stumped me. Hoe does the Sony FX1/Z1 deinterlace in camera? I ask because I am curious what affect this has on the 4:2:0 color space. Anyone know?

March 15th, 2005, 07:27 PM	#2
Douglas Spotted Eagle VASST Join Date: Jan 2004 Location: Stockton, UT Posts: 5,648	I'm not sure why someone would ask that question. 4:2:0, 4:2:2, 4:1:1, or whatever other luma/chroma sampling scheme used isn't related to interlaced or non-interlaced, or deinterlaced. you can have any flavor of the above in p-scan or interlaced or deinterlaced. __________________ Douglas Spotted Eagle/Spot Author, producer, composer Certified Sony Vegas Trainer http://www.vasst.com

March 15th, 2005, 08:10 PM	#4
Douglas Spotted Eagle VASST Join Date: Jan 2004 Location: Stockton, UT Posts: 5,648	I just did a test, you can easily repeat. Shoot colorbars or something of mixed colors. (I used a color chart) Shoot all modes. Capture. Grab stills of all modes. drop stills into Photoshop. Use the eyedropper, compare colors. you'll not find differences between the two modes. In fact, deinterlace in your app, and do the same thing. The only thing you should see is some loss in sharpness. __________________ Douglas Spotted Eagle/Spot Author, producer, composer Certified Sony Vegas Trainer http://www.vasst.com

March 16th, 2005, 03:13 PM	#6
Douglas Spotted Eagle VASST Join Date: Jan 2004 Location: Stockton, UT Posts: 5,648	Polka dots yes, plaids...no. I don't have any, and frankly hadn't considered it. On my way to Walmart....I'll report back later. __________________ Douglas Spotted Eagle/Spot Author, producer, composer Certified Sony Vegas Trainer http://www.vasst.com

March 15th, 2005, 07:55 PM	#3
Aaron Shaw Major Player Join Date: Jul 2004 Posts: 587	Yes I know. I'm just curious how the deinterlacing handles the chroma from the two fields when blending them. Is there a loss of chroma (ie less than 4:2:0), is there a gain, nothing? For instance, when down converting you can get full chroma by throwing out one of the fields. While this isn't the same thing, I do wonder what effect the field blending has on the color per any given area.

March 16th, 2005, 02:10 PM	#5
Joe Carney Inner Circle Join Date: Jul 2002 Location: Centreville Va Posts: 1,828	Spot, just a thought, has anyone tested these new cameras against highly contrasting plaids and polka dots (the bane of dv25)?

March 18th, 2005, 10:41 AM	#7
Andre De Clercq Major Player Join Date: Sep 2002 Location: Belgium Posts: 804	Sampling raster doesn't affect colorspace properties in terms of color rendition. There is however a known issue (the "chromabug") when 4:2:0 footage needs to be deinterlaced. Maybe the artifacts are less visible in HDV than they are in SDDV