Canon Progressive Scan

DavidPJ wrote on 5/7/2003, 8:19 AM
For the years I've owned my Canon Elura I've never recorded in progressive scan other than to test it. Now than I'm editing with Vegas, is there any reason not to always record in progressive scan mode? The Canon Elura users manual makes a very vaque statement that sometimes video recorded with progressive scan may appear jerky. What are the advantages & disadvantages of using the camera's progressive scan? Thanks.

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FuTz wrote on 5/7/2003, 8:32 AM
OK, I use a Sony but here's some info I got a few time ago...

Subject: Progressive VS non-progressive
Posted by: fUtZ (Ignore This User)
Date: 1/22/2003 10:29:55 AM

Do you really see a big difference between shooting progressive VS non-progressive ?
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Subject: RE: Progressive VS non-progressive
Posted by: jboy (Ignore This User)
Date: 1/22/2003 3:17:19 PM

Good question. I know that one liability in progressive, is that it puts jaggies on diagonal lines. What are the benefits ? Since you're shooting thru the same camera ccd chip, can there be any difference in picture quality ?
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Subject: RE: Progressive VS non-progressive
Posted by: Grazie (Ignore This User)
Date: 1/22/2003 3:19:38 PM

I've just been reading on the DVinfo web, with respect to X/M2 Canon camcorder the value of progressive scan for allowing smooooth slomo - yes?

Grazie
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Subject: RE: Progressive VS non-progressive
Posted by: fUtZ (Ignore This User)
Date: 1/22/2003 4:07:16 PM

Grazie, you reminded me that: someone on this forum said a few time ago that he shot "progressive" exactly for that purpose: to get smoooooth slow-mo's. You're right!
But apart from that: the colors, the overall signal? I ask cause there seems to be some tweakings and adjustments to make it all work flawless...having two fields filling the picture, you really have to "mind the gap" in progressive... hee hee! ;)
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Subject: RE: Progressive VS non-progressive
Posted by: Paul_Holmes (Ignore This User)
Date: 1/22/2003 5:27:41 PM

Actually, somewhere on the forum I saw a post saying that shooting at 60i interlaced was the best for creating slowmo, because it had more inbetween frames to interpolate from.

I used to have a Canon Optura Pi which I shot at 30fps and liked the look, and you could extract nicer stills from it. Now, however, I do what DVFilmmaker recommends, which is shoot interlaced, then process it with DVFilmmaker. I think it creates a better-looking progressive look than the 30fps mode.
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Subject: RE: Progressive VS non-progressive
Posted by: sqblz (Ignore This User)
Date: 1/23/2003 9:38:31 AM

I may be off-topic here because you seem to be talking about progressive or intelaced movie taking (I don't even know how to do it), and I am concerned with progressive / interlaced rendering.

I really don't know !!! I take my scenes as my DV Camera wants, I capture them as Vegas wants, and that's it. And the first time that I am called to decide is at the time of rendering ...
Decisions, decisions ...

I have noticed that my "interlaced" renderings represent vertical straight lines as finely jagged lines when I see them in my PC monitor. Might that be the 575 (?) lines of TV ? Dunno. Might the jagging disappear with "progressive" rendering ? Now testing ...

I remember one older posting here about capturing stills. Someone gave a hint that I regularly use, which is altering the properties of the clip from interlaced to progressive, before making the grab. And it works, much sharper grab ...
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Subject: RE: Progressive VS non-progressive
Posted by: mikkie (Ignore This User)
Date: 1/23/2003 11:50:02 AM

Check out Adam Wilt's site for the technical side of things, but in essence, the way a particular camera arrives at an interlaced or progressive frame has a lot to do with the results.

Also, it helps to remember your intended audience. If you're going out to tape or similar to be viewed on a std interlaced TV, somewhere along the chain the video stream has to be converted to interlaced. If you've got progressive footage, then view it on a std tv monitor, you're not looking at progressive any longer so the benefits would be debateable.

FX, Slo-mo or stills would be the exception, because you're working with something outside of the normal 50 - 60 field per second. Instead of a bunch of broken up fields you get some nice data that something like Vegas can play with - something closer to photographs - & then it's usually converted to interlaced (broken up). Like the old "garbage in - garbage out", you're giving your equipment more to work with, and sometimes it shows up.

mike
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Subject: RE: Progressive VS non-progressive
Posted by: cheesehole (Ignore This User)
Date: 1/23/2003 6:00:10 PM

just to add to Mikkie's post and answer some ??'s

>>>Do you really see a big difference between shooting progressive VS non-progressive ?

yes it looks very different. 60i tends to have a liquid smooth look while 30p doesn't. if your target viewing platform is progressive (PC/Web/Digital Projector/etc), my choice would be to shoot progressive for sure, but there are factors at work with the camera too. for example, on the Cannon GL-1 you have to sacrifice a little bit of effective resolution in progressive mode because of the way the CCD works. this is not a limitation of progressive DV mode, but a technical limitation of the camera.

>>>Good question. I know that one liability in progressive, is that it puts jaggies on diagonal lines.

this is not true unless you are talking about rendering interlaced video to progressive, which generally isn't a useful idea but I guess some people get good results using special software.

>>>What are the benefits ? Since you're shooting thru the same camera ccd chip, can there be any difference in picture quality ?

using the GL-1 as an example, it uses tricks to get better resolution looking at the two fields, but it can't use those tricks when in progressive mode, so there is a difference in picture quality. I still shoot progressive because I really like the look and my target equipment is almost always progressive. plus I love to grab stills out of video. that is a photographic art in itself. they don't look great printed out, but they look pretty nice for video or web use.

>>>the value of progressive scan for allowing smooooth slomo - yes?

I prefer to shoot in interlaced mode when I know I'm going to do slow motion because of those extra samples. I'm usually trying to demonstrate something, or show more detail when using slow motion, so having twice as many time samples is crucial. but if drama is your intention, then it's just a matter of preference.

>>>I may be off-topic here because you seem to be talking about progressive or intelaced movie taking (I don't even know how to do it), and I am concerned with progressive / interlaced rendering.

if your source is interlaced and your target viewing platform is interlaced you should probably stick with rendering to interlaced. this resource really helped me understand how different equipment deals with interlaced/progressive material and I recommend reading it:
Progressive Scan DVD
it's supposed to be a review of progressive scan DVD players, but it's loaded with so much background information that it's worth reading even if you aren't interested in DVD players.
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Subject: RE: Progressive VS non-progressive
Posted by: fUtZ (Ignore This User)
Date: 1/24/2003 8:25:47 AM

thanks for the replies everybody. I got plenty of info there so I guess I'm gonna read a little more on the subject thanks to your references! :D


Luxo wrote on 5/7/2003, 11:01 AM
...here's a link to the actual thread fUtZ copied and pasted.

Experiment with the progressive mode. Any motion will indeed look more jerky, and you can even see this evidenced in the viewfinder when panning the camera. This is because progressive mode has less temporal resolution (30 progressive fps, as opposed to 60 fields per second). On the other hand, it looks much sharper, and you can pause any single frame and see a beautiful flicker-free image. Some think the progressive mode looks less like video, and closer to film.

I use progressive mode when shooting a talking head, or other footage without heavy motion of the subject or camera. Otherwise, regular interlaced mode is what I like.

One tip: do not use progressive mode if you plan to apply slow motion effects, as you want as much temporal resolution as possible to stretch time.
shawnm wrote on 5/7/2003, 1:41 PM
I've actually had good luck using progessive scan mode for high motion shots. Take a look at this video. It took some tweaking to get the playback this smooth, but I'm happy with the result. At first I was just going to shoot 30i, but right before we started shooting, someone requested screen grabs from that day's shoot, so I switched to 60p. You can see the results .

Thanks,

Shawn
Bill Ravens wrote on 5/7/2003, 2:32 PM
It's not really progressive scan, it's still 60i. True progressive scan is 30p.
DavidPJ wrote on 5/7/2003, 3:27 PM
Thanks everyone for the great information regarding progressive scan!

Dave
FuTz wrote on 5/7/2003, 3:36 PM
shawnm: so what you mean is that for these high motion shots if you hadn't tweak those it would have appeared like a strobed image?

And what's the difference between 60 interlaced and 30 progressive? I figure out 60i is much smoother (ie no strob effect) ?
shawnm wrote on 5/7/2003, 4:22 PM
"shawnm: so what you mean is that for these high motion shots if you hadn't tweak those it would have appeared like a strobed image?"

Hey Futz,

That's actually what happened when we first started shooting. These guys were moving so fast that their weapons and hands were disappearing or "strobing", especially the weapons - so we re-positioned the lights, and set the shutter speed to 1/60 (don't remember the F-stop setting). After that, we got some pretty decent results. I was actually surprised that the stills came out as sharp as they did.

Shawn
FuTz wrote on 5/7/2003, 4:34 PM
... nice!...
Surprising how the stills are sharp.

I think I gotta experiment with shutter speeds and progressive mode on my cam. I still don't exactly figure out what's gonna "strobe" and not...I even don't remember if I can set a shutter speed IN prog mode...