GS400 test pattern results

Rokta Bija · September 19th, 2004, 07:08 PM

Seeing the DVC30 thread about 50% loss in frame mode, I thought I'd do a test with the GS400 comparing interlaced to frame.

Test conditions were not great, hand held, indoors, auto focus, low light.

Despite that the most striking thing was that frame mode displayed just as good of vertical line resolution as interlaced. Horizontal res is very crisp. In fact most of the frames looked slightly better in frame mode than interlaced, but that could have been my shaky hand.

I would like to see someone else verify this. I am skeptical about the results, but I double checked the each clip on the timeline to make sure one was interlaced and one was progressive. They were.

http://users.adelphia.net/~jp1/normal.jpg

http://users.adelphia.net/~jp1/frame.jpg

Boyd Ostroff · September 19th, 2004, 09:11 PM

The vertical resolution in the frame mode chart looks like what you would expect from normal 60i video, around 360 lines. So it doesn't seem to be doing field doubling. But it probably isn't doing real progressive scan either, or we would see higher resolution than that....

Guy Bruner · September 19th, 2004, 09:45 PM

Yes, that is consistent with my tests. There is no discernable difference between interlaced and frame mode.

Rokta Bija · September 19th, 2004, 11:24 PM

It is strange though that the DVC30 does show some loss, about what you would expect if Panasonic is still doing same green line pixel shifting described in that article they wrote. (linked to elsewhere on this forum)

Maybe the extra pixels in the 400's CCD's would explain some of it, but I don't see any loss at all, they look indentical.

Makes you wonder if they are doing frame mode differently now, like just combining the two fields without pixel shifting.

Alvin Tan · September 19th, 2004, 11:34 PM

Oh, do most people use frame mode or interlaced mode? Sorry I'm new at this. What's the advantage and if I intend to create DVD later, which mode should I be using? Thanks.

Boyd Ostroff · September 20th, 2004, 06:22 AM

I suppose the GS400 might be doing some sort of deinterlacing in firmware, like we might do with software in post? Looking at some frames with motion in them might give a clue to this....

Mikhail Transact · September 20th, 2004, 01:28 PM

I've get similar results for PAL GS400
normal
frame

Bruce Simpson · September 20th, 2004, 08:05 PM

<<<-- Originally posted by Alvin Tan : Oh, do most people use frame mode or interlaced mode? Sorry I'm new at this. What's the advantage and if I intend to create DVD later, which mode should I be using? Thanks. -->>>

I use interlace mode for most work but when I'm filming fast-action footage with a fast shutter speed I use frame mode so that I can grab single images if I want to. The reason I use a fast shutter is to freeze the motion in each individual frame. It's much easier to get just the right action still this way -- rather than trying to hit the shutter at exactly the right moment in card-mode.

If you use interlace mode with high shutter speeds the results are not pretty when examined on a frame-by-frame basis in the face of rapid movement :-)

September 19th, 2004, 07:08 PM	#1
Rokta Bija Regular Crew Join Date: May 2004 Posts: 61	GS400 test pattern results - frame vs interlaced Seeing the DVC30 thread about 50% loss in frame mode, I thought I'd do a test with the GS400 comparing interlaced to frame. Test conditions were not great, hand held, indoors, auto focus, low light. Despite that the most striking thing was that frame mode displayed just as good of vertical line resolution as interlaced. Horizontal res is very crisp. In fact most of the frames looked slightly better in frame mode than interlaced, but that could have been my shaky hand. I would like to see someone else verify this. I am skeptical about the results, but I double checked the each clip on the timeline to make sure one was interlaced and one was progressive. They were. http://users.adelphia.net/~jp1/normal.jpg http://users.adelphia.net/~jp1/frame.jpg

September 20th, 2004, 01:28 PM	#7
Mikhail Transact Regular Crew Join Date: May 2004 Location: Moscow, Russia Posts: 60	I've get similar results for PAL GS400 normal frame __________________ Mikhail

September 20th, 2004, 08:05 PM	#8
Bruce Simpson Regular Crew Join Date: Apr 2004 Location: New Zealand Posts: 34	<<<-- Originally posted by Alvin Tan : Oh, do most people use frame mode or interlaced mode? Sorry I'm new at this. What's the advantage and if I intend to create DVD later, which mode should I be using? Thanks. -->>> I use interlace mode for most work but when I'm filming fast-action footage with a fast shutter speed I use frame mode so that I can grab single images if I want to. The reason I use a fast shutter is to freeze the motion in each individual frame. It's much easier to get just the right action still this way -- rather than trying to hit the shutter at exactly the right moment in card-mode. If you use interlace mode with high shutter speeds the results are not pretty when examined on a frame-by-frame basis in the face of rapid movement :-) __________________ ----- No problem too small to baffle this expert

September 19th, 2004, 09:11 PM	#2
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,802	The vertical resolution in the frame mode chart looks like what you would expect from normal 60i video, around 360 lines. So it doesn't seem to be doing field doubling. But it probably isn't doing real progressive scan either, or we would see higher resolution than that....

September 19th, 2004, 09:45 PM	#3
Guy Bruner Major Player Join Date: Nov 2003 Location: Ashford, AL Posts: 937	Yes, that is consistent with my tests. There is no discernable difference between interlaced and frame mode.

September 19th, 2004, 11:24 PM	#4
Rokta Bija Regular Crew Join Date: May 2004 Posts: 61	It is strange though that the DVC30 does show some loss, about what you would expect if Panasonic is still doing same green line pixel shifting described in that article they wrote. (linked to elsewhere on this forum) Maybe the extra pixels in the 400's CCD's would explain some of it, but I don't see any loss at all, they look indentical. Makes you wonder if they are doing frame mode differently now, like just combining the two fields without pixel shifting.

September 19th, 2004, 11:34 PM	#5
Alvin Tan Tourist Join Date: Sep 2004 Posts: 4	Oh, do most people use frame mode or interlaced mode? Sorry I'm new at this. What's the advantage and if I intend to create DVD later, which mode should I be using? Thanks.

September 20th, 2004, 06:22 AM	#6
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,802	I suppose the GS400 might be doing some sort of deinterlacing in firmware, like we might do with software in post? Looking at some frames with motion in them might give a clue to this....