How does progressive resolution compare to interlaced?

[Bill Edmunds]

Is there any difference in resolution between 30p and 60i on this camera? Can Final Cut Pro "revert" the 30p/24p pulldown format to a native 30p/24p, or must it stay as a 60i signal with pulldown? Is there any reason to revert it back to native 30p/24p in the first place?

[Bill Edmunds]

Anyone? Basically, I'm trying to compare the V1u to the Canon A1, which has a faux-progressive feature and reduces resolution by about 10%.

[Marcus Marchesseault]

I don't think there is an appreciable resolution difference. As you may know, the V1 always records in a 60i format but you could convert that to a progressive format depending on your software. I don't use FCP and haven't even done it yet in Vegas. I'm playing with some 30P footage now, so I'll experiment some time in the near future. I'm sure someone else will comment before I get around to testing though.

[Douglas Spotted Eagle]

There is nothing "faux" about how either Canon or Sony place their 24p stream in a 60i package.
it's not a "convert" to 24p, it's "extract the progressive frames from the 60i package" process. There are flags/indicators in the 60i stream instructing the NLE which frames to remove.
Progressive has greater resolution by nature of what it is. Interlaced at identical framerates is smoother motion. ie; a 30p image will have greater resolution than its 60i counterpart, but the 60i counterpart will have smoother motion as a result of having twice the number of opportunities to record/display motion.

[Bill Edmunds]

Originally Posted by Douglas Spotted Eagle

There is nothing "faux" about how either Canon or Sony place their 24p stream in a 60i package.

I know the Sony's isn't a faux progressive image, but I was under the impression that the Canon's isn't true progressive. I do know that the Canon's 24f and 30f modes do not boast the resolution of its 60i image.
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[Piotr Wozniacki]

Bill,

Seems like very few people really know how the 30/25F is arrived at with Canon, the imagers being interlaced - the truth is you cannot see a resolution drop from 50/60i with your naked eye.

With Sony V1, you have true progressive imagers but the progressive picture is also written within the interlaced stream for compatibiliy reasons, thus becoming the 30/25PsF (progressive segmented frames). Of course both Sony and Canon in their US models also have the 24p mode, which is written within the 60i stream and employs the pulldown technique.

As to the resolution of the V1 in progressive, some tests have suggested that while even better than interlaced in good lighting conditions, it falls somewhat with gain over 9dB due to noise reduction algorithm kicking in. I personally try to never exceed 9dB of gain anyway, so 99% of my footage is progressive (25PsF), and I'm absolutely satisfied with the quality.


And - progressive or not - my opinion is that the V1 gives a sharper picture generally than the Canon A1.

[Mikko Lopponen]

Originally Posted by Piotr Wozniacki

Bill,

Seems like very few people really know how the 30/25F is arrived at with Canon, the imagers being interlaced - the truth is you cannot see a resolution drop from 50/60i with your naked eye.

That's weird considering that there's a thread in the xh a1 category about stairstepping in 25p material. That would mean that there's a visible resolution drop.

[Piotr Wozniacki]

Haven't seen that thread, but can assure you there's nothing like stair-stepping in the Canon 25F mode - had it for a couple of weeks and tested thoroughly.

[Bob Grant]

One 'problem' with the V1P in progressive is you could argue it has too much vertical resolution. This can lead to some issues with display devices that don't work out that it's 25PsF and display it as 50i. Hardly the cameras fault though and the general public see so much line twitter in downscaled HD anyway and never seem to notice.

[Piotr Wozniacki]

Originally Posted by Bob Grant

One 'problem' with the V1P in progressive is you could argue it has too much vertical resolution. This can lead to some issues with display devices that don't work out that it's 25PsF and display it as 50i. Hardly the cameras fault though and the general public see so much line twitter in downscaled HD anyway and never seem to notice.

Oh, this has been so exhaustively discussed between you, Steve and myself that I didn't event want to mention it:) Definitely a display problem!

[Mikko Lopponen]

Originally Posted by Piotr Wozniacki

Haven't seen that thread, but can assure you there's nothing like stair-stepping in the Canon 25F mode - had it for a couple of weeks and tested thoroughly.

http://www.dvinfo.net/conf/showthread.php?t=103233

[Piotr Wozniacki]

C'mon Mikko - do you really consider these branches' "jaggies" a major flaw? Can you actually see them in the video (as opposed to still frames, perhaps blown up with PS)?

[Mikko Lopponen]

Well if I do a basic deinterlace then the video will have the same "small jaggies". So yes, I consider it an issue. Why use 25f when I can just do the same in post?

[Piotr Wozniacki]

I guess you've got a point here - the Canon's 25F must be obtained through some smart in-camera deinterlacing...But it's very smart indeed:

- real-time performance (how long does it take to deiterlace in your NLE?)
- no visible resolution drop (some tests claim it to be 10-12%; again, compare it to your NLE performance)

I'm not a Canon fanboy (to the contrary - see my sig) - but I must admit the 25F is really very, very clever.

[Paul Frederick]

One of the original questions in this post is still unanswered and I for one am curious about it: If you shoot in 30p, how do you handle it in post? I know there is no pull down needed, but since it's "wrapped" in a 60i stream, does it need anything done to it? Do you edit in a 60i timeline?