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Mikael Widerberg August 17th, 2005 01:00 AM

Framerate
 
What's the difference between HDV-SD50P and HDV-HD25P?

I am going to make a film about kayaking and needs to have all the settings right from the start.

Everything is in PAL.

It will finely be encoded to a DVD.

Barry Green August 17th, 2005 01:14 AM

SD50p is standard-definition resolution. It's the same resolution as DV, 720x576, but it's shooting progressive frames. It's 50 frames per second, so it will give the "reality" look -- the "video" look, at standard-definition resolution.

HD25p is high-definition 720p, running at 25 frames per second. It will not have the "video" look, it'll have more of a "film" look. But it'll be 1280x720, not 720x576.

David Slingerland August 17th, 2005 06:17 AM

hallo Barry,

That can not be right because there is already a setting called DV 50I and DV 25P.. That has got me also confused to why they would call it HDV-SD50P, it must be HDV shot at 50 frames as to HDV SHOT at 25 frames?(HDV-HD25P)

Kevin Dooley August 17th, 2005 06:35 AM

David,

It's considered HDV because it's shot in progressive frames and it's MPEG2 encoded... but it is 720x576. It's not considered DV because of the progressive frames.

David Slingerland August 17th, 2005 08:56 AM

I dont think you understood what I was trying to say

the settings is called HDV-SD50, it is HDV.....
DV50I is dv that is standard definition...the answer Mikael is looking for is what does SD mean in HDV-SD50, it does not mean standard def because there are already other SD settings....They are called DV50 or DV60.
I am not referring to progressive HD or SD

Nate Weaver August 17th, 2005 09:20 AM

Quote:

Originally Posted by David Slingerland
the answer Mikael is looking for is what does SD mean in HDV-SD50, it does not mean standard def because there are already other SD settings....

It DOES mean standard def. The reason it's called HDV rather than DV is because there's no official standard for 50P in the standard def world for writing to tape, but there IS one in the HDV world.

We understand the question completely.

David Slingerland August 17th, 2005 09:23 AM

so you mean the camera can write 25p 50p and 50i on standard def??
Why 50p ? is it segmented...to match 50 frames interlaced or what?
thanks

Nate Weaver August 17th, 2005 09:52 AM

Quote:

Originally Posted by David Slingerland
so you mean the camera can write 25p 50p and 50i on standard def??
Why 50p ? is it segmented...to match 50 frames interlaced or what?
thanks

Yes. The thing writes a lot of formats!

Why 50P? Because they can, I guess. Somebody somewhere wants it. It is not segmented...there would be no such thing at such a high frame rate.

It writes 50 (or 60, in the U.S.) individual standard definition frames in an MPEG2 stream. The result would be something that looks like standard 50i or 60i video, except that much clearer because the interlacing would be gone.

Barry Green August 17th, 2005 11:56 AM

Correct. It's a new format. It is not PAL. It's "more than PAL". It is the same pixel dimensions as PAL, but twice as many pixels per second.

It may not truly be high-def, but maybe you could think of it as "enhanced definition".

This format's been around for a few years -- JVC first introduced the MPEG-2 720x480x60p format on its GR-HD1 camera. That camera had three modes: DV, HD, and "SD" -- and the SD mode was standard-def at 60p, recorded in MPEG-2 (exactly what the HD100 offers). When JVC introduced the European version of the camera, calling it the GR-PD1, they took out the high-def mode but they left the standard-def 720x576x50p MPEG-2 mode in there.

There are a few advantages to it. First, it's universal among the HDV 720p format, so both US and European cameras will get both the 480/60p and 576/50p modes. So even though the camera isn't PAL/NTSC switchable, the US version will be able to generate 576/50P footage that can easily be converted to PAL, and the European version will generate 480/60p footage that can easily be converted to NTSC.

Second, it provides for ultra-mega-smooth slow motion in your standard-def productions. You chould shoot your regular production in 576/25P, and shoot your slow-mo portions in HDV-SD50P, and import that into your 25P timeline and get full-frame, full-resolution superb slow motion.

To sum up, in standard-definition 720x576, the JVC shoots:
DV 576/50i
DV 576/25P
MPEG-2 HDV-SD 576/50P
and also MPEG-2 HDV-SD 480/60P

That's in addition to the high-def modes of 24P, 25P, and 30P.

Mikael Widerberg August 17th, 2005 01:32 PM

Okay, I think I understand. Thanks alot for your answer. I have the camera, I am just missing the firewire cable, so I am not able to get the clips into my computer at the moment.

Cheers!

David Slingerland August 18th, 2005 03:46 AM

Incredible!! Just wish there was support for it from AVID or FCP...When will that be?? lets hope the coming IBC...

Michael Maier August 18th, 2005 07:15 AM

I'm actually thinking about using the 576 50p for slow motion and mixing it with the 720 25p. I wonder if the resolution difference will be that noticeble. The slow motion shots would have a lower resolution, but would be real progressive. Chances are it would still look better than if I just slowed down the 720 25p in post.
Also, I wonder if using 30p would produce any slow motion at all when played in 24p or 25p.

Steve Gibby August 18th, 2005 10:11 AM

Seems to me the resolution difference between 576p50 and 720p25 should not be that noticable. If you're just using the 576p50 footage as slo-mo, viewers would be concentrating on the action of the subject you have in the slo-mo (sports, animal running, etc.), and probably wouldn't even notice the slight drop in resolution. The slowed 576p50 should look much smoother than slowed 720p25. In creating a slo-mo, the higher the frame rate, the better. If it was me, I wouldn't mind losing a little resolution by going to the 576 for slo-mo, because the gain in smoothness of the slo-mo would justify it. If you're televising the sequence, and the network/station has 720p as their high definition standard in the Producer's Guidelines, most stations and networks allow for short "lookback" or slo-mo sequences to be in a lower resolution if necessary.

If it's 576p50 actually transferred to 720p30, Barry Green gave some good input previously on another thread of this board.

As for 30p played at 25p or 24p, if you're looking for a real effective and smooth slo-mo, the higher the frame rate of the source footage, the better the end result.

Barry Green August 18th, 2005 01:00 PM

Quote:

Originally Posted by Michael Maier
The slow motion shots would have a lower resolution, but would be real progressive. Chances are it would still look better than if I just slowed down the 720 25p in post.

We face this exact issue with the DVX -- you can try to get slow-mo by playing 24P footage back at half speed, which means you get full frame resolution but it's choppy. Or, you can shoot your slow-mo at 60i and play that back at 40% speed... which means you get perfect motion rendition, but the resolution is lower. For my taste, I prefer the 60i-slowed-down. Basically if I want slow motion, the point of the shot is the motion -- and 60i provides 60 samples per second, for accurate motion rendition. Sure is softer though. In some ways that works okay, because when you see slow-motion it's usually surreal anyway, so the softness doesn't work against you too much.

Quote:

Also, I wonder if using 30p would produce any slow motion at all when played in 24p or 25p.
Yes, 30P would produce luscious frame-accurate slow-motion when played back in a 24p project (or 25p). In 24P it provides for 25% slower motion, in 25p it'd be 20% slower. It's not a lot, but it is noticeable and it works very, very well on the DVX; I cannot think of why it wouldn't work equally well on the HD100.


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