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Old September 16th, 2005, 07:31 AM   #1
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Jerky motion in playback...ideas?

Hi...
I should first preference this with saying I have little experience with professional cameras so any help you can provide feel free to "dumb it down"

I recorded some video using the HDV-HD30P setting and then played it on my Sony HD TV. When the camera is is not panning, the image looks GREAT! However, when I pan from right to left, the image has a jerky motion, the image shakes. Hopefully this makes sense.

What I am trying to figure out is what is the best setting for filming in HD. I don't understand a lot of the features that are on the camera, but I feel like I would need to to get smooth pans.

I thought maybe it was my TV, but when I use the TV as a monitor and pan around the room with the camera, the shot looks great...the jerky motion appears when I am playing it back. Any help would be greatly appreciated.

Craig
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Old September 16th, 2005, 07:48 AM   #2
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You're encountering the limitations of shooting in 30P. The monitor shows you a live feed at 60P (sixty frames per second) but the camera can only record a maximum of 30P (thirty frames per second).

In other words -- you get what you get. You cannot get that "live" look, recorded to tape. It simply isn't possible.

The HD100 will take some practice -- if you're used to shooting film or 24P video, the HD100's 24P delivers the same type of results. But if you're looking for the smooth 60i/60p look, the HD100 cannot do that (when recorded to tape). Your only option is to learn to shoot for 30P (or 24P), moving the camera like a film camera, tracking objects when panning, etc.
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Old September 16th, 2005, 08:38 AM   #3
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You know I've put some thought to this.

Try 'smooth motion' mode. I think the idea is, since film projectors have a 2- or 3-bladed shutter which softens movements jerkiness, 'smooth motion' was made to emulate that softening effect of a film projectors shutter.

Give it a try when you can and post the results.
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Old September 16th, 2005, 09:48 AM   #4
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I appreciate the quick responses.

I switched the mode to smooth motion. This is what the folks at JVC had me do as well and I got the same results. The same jerky motion.

Now, I'm getting worried, Barry. Will I not be able to pan back and forth? There is no way to pan from right to left across a room without getting that jerky motion using 30P?

What if I record in HDV-SD60P? Is that still HD? (This question, probably shows my limited knowledge). I am a middle school teacher wanting to create a HD video for my 7th graders? I edit using FCP 5. Is this camera just out of my league? My previous camera was a 3 chip sony.

I'm worried to hear your response....I hate bad news...

-Craig
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Old September 16th, 2005, 10:37 AM   #5
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Quote:
Originally Posted by Craig Brandenburg
Now, I'm getting worried, Barry. Will I not be able to pan back and forth? There is no way to pan from right to left across a room without getting that jerky motion using 30P?

That's the way 30 and 24p is. One thing you'll learn is that strobing in those modes is perceptual issue, that is, you'll only notice it in certain circumstances.

When you pan across a scene and there's no central item your eye is following (like an actor, or car, etc), all your eye notices is the stutters. When you put something else in there that is NOT moving with the background that your eye would lock onto (say, an actor walking across, or etc), your eye follows that item of interest and the strobing goes away.

It sounds like I'm describing a situation like "don't worry, you'll get used to it". It's a little like that, but more of "In practical shooting situations, other things will take care of it".

Motion picture film has the EXACT same problem, and chances are, you've never noticed it before. There's two reasons for that:

1-If you're watching a movie, that means in every frame there's something you're intended to look at. A central item, character, etc. Something for your eye to lock onto.

2-If for some reason there's a rare shot where there ISN'T the above, then there are a set of rules to follow for panning speeds when shooting at a given frame rate. The American Cinematographer's Manual has a chart of these, and they're old as dirt.

In short, don't sweat it. I find myself that I notice 24P and 30P strobing MUCH more when I'm critically evaluating picture quality of a camera (i.e. eyes locked to the CRT, staring into details of the image). When I'm shooting and editing a piece, the human brain will usually lock onto other things.

Hope this helps...
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Old September 16th, 2005, 10:54 AM   #6
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Quote:
Originally Posted by Craig Brandenburg
Now, I'm getting worried, Barry. Will I not be able to pan back and forth? There is no way to pan from right to left across a room without getting that jerky motion using 30P?
Filmmakers have been panning for over 100 years with film. Shooting progressive does not mean you cannot pan, you just have to follow the rules.
If you have access to an American Cinematographer Manual (check your local library for eighth or ninth edition,) check out the chart on "recommended panning speeds."
The focal lengths listed refer to 35mm film, so on the stock HD100 lens lets assume the equivalent at full wide is about 28mm, and full telephoto is around 300mm.

So the chart says at 24P, to pan no more than 6.3 degrees per second at the widest focal length, and no more than 0.58 degrees per second at telephoto. Of course "whip pans" don't count, and shooting at 30P will give you even smoother motion than 24P.

Quote:
What if I record in HDV-SD60P? Is that still HD?
No, that is 480P (standard Def NTSC) recorded within an "HDV" m2t stream. However you will get a super smooth image, and you can pan 'til your heart's content.

Quote:
Is this camera just out of my league? My previous camera was a 3 chip sony.
I'm not sure how much experience you have, but I can tell you that this camera was designed for professional filmmakers. There will definitely be a steep learning curve for those not already familiar with similar cameras.

If your experience is with a 3-chip Sony (PD150 or VX1000/2000), and you were compfortable working with a fixed lens, limited dynamic range, etc., then maybe you should trade your HD100 in for a HDR-FX1 or Z1. It shoots interlaced so you won't ever have a "panning problem!"
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Old September 16th, 2005, 10:57 AM   #7
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As much as I hate to say this if it bothers you that much you could try and shoot with a shutter speed of 30 instead of 60. This blurs the motion a lot and isn't very real looking but isn't as jerky. For times when you do need fast pans this may help those shots.
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Old September 16th, 2005, 11:43 AM   #8
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shutter speed

in addition to everything elses thats been said, definately check your shutter speed. It will add to the jerky motion if your shutter speed is too fast.
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Old September 16th, 2005, 12:06 PM   #9
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The video looks great in the pop-out screen. Does this have something to do with progressive vs. interlaced?

-Craig
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Old September 16th, 2005, 12:18 PM   #10
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Quote:
Originally Posted by Craig Brandenburg
The video looks great in the pop-out screen. Does this have something to do with progressive vs. interlaced?

-Craig
The "live" image in HD will look smoother than what is actually recorded and played back later. It seems the EVF, LCD, and outputs show 720p60 during recording.
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Old September 16th, 2005, 02:42 PM   #11
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Quote:
Originally Posted by Craig Brandenburg
Does this have something to do with progressive vs. interlaced?

-Craig
Well, yeah. Shooting interlaced you're seeing 60 seperate images per second. 30P, you're seeing only 30.

Here's the deal though. Smooth motion isn't the only consideration. A lifetime of viewing interalced 60i video has conditioned us to think that 60i video looks like the evening news, or say, a soap opera.

Narrative storytelling like episodic dramas, movies of the week, movies, etc has traditionally been shot on film, so 24P or 30P (30P is usually compared more to 24P than 60i) look like a "movie".

So if you choose 60i to shoot your short film because you feel it won't stutter, understand most people are going to say it looks like a soap opera. But you did get your smoothest motion.
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Old September 16th, 2005, 09:37 PM   #12
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Everyone's answers here are correct.

To get to the heart of the matter, when you say "will I not be able to pan?" the answer is: you will not be able to pan as freely as you did with a 60i video camera, no -- the slower frame rate of 30p (or 24p) will jitter under those circumstances.

You have to slow down your motions. Or, you have to speed them up -- if you do a "swish pan", people won't notice the strobing. But there's a big "dead zone" between "slow enough" and "fast enough" where you simply can't just execute a glass-smooth pan... the frame rate doesn't allow for it.

So, as Nate said, film cinematographers (who deal with this issue every day) will either follow a subject (such as a person walking through the shot) to keep the viewer's eye focused on the subject rather than the strobing background; or, they'll pan really slowly. At certain slow speeds, 30P (or 24P) can be glass-smooth. But we're talking S L O W speeds.

The 480/60P mode is named something like HDV-SD. It's a standard-definition mode, not high-def. However, it's implemented in the HDV standard... it's actually technically EDTV (Enhanced Definition TV). When shooting 480/60P you'll get super-smooth, better-than-interlaced footage, it's absolutely magnificent -- but it's only standard-def. If you wanted to use this in your high-def footage, you'd have to digitally up-rez it, which will obviously have an impact on the quality of the footage.

Fox and ABC and ESPN all broadcast in 720p, but they shoot and broadcast 720/60p. The JVC can shoot 720/60p, but cannot record it. It can only record 720/30p and 720/24p; the hardware is not capable of processing a 60p data stream. So on tape (or out the firewire) you will never get that "reality" look (the "news" / "soap opera" look). It just can't do it. But you can get a very cinematic look, provided you handle the camera like a film camera and don't treat it like a "video" camera.

If you need to record the smoothest footage you can get, obviously 30P will give you a smoother image on tape than 24P will -- 30P gives you 20% more frames per second, thus a visually smoother image. The suggestion to use 30P at 1/30th shutter speed will also give you smoother imagery, but at the expense of it being blurrier. "Motion Smoothing" uses a 60p image stream, blending two frames together to try to give a representation of smoother motion. In the times I've used it, all it appears to do is give a double image, which makes the motion blurrier. Not very desirable; however, you can test it yourself and see if you like the effect.

But if the question you're asking is: can I get my HD100 footage to look as smooth as 60i or 60p footage, the answer is no, that's not possible. You have a 30P camera; you have to learn to shoot at 30P in such a way as to deliver what you consider acceptable results. And that's going to take practice.
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Old September 17th, 2005, 01:44 AM   #13
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Click on this and see if it seems jerky to you:

Click here to view wmv

This was the 30P that Nate Weaver shot/posted and I edited for effect. The 30P looks pretty smooth in this instance. It was rendered progressive so what you see is what I had on my timeline.

Last edited by Stephen L. Noe; September 17th, 2005 at 04:45 PM.
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Old September 17th, 2005, 11:24 AM   #14
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Regarding shooting in 480p60, I've considered using it for B-roll or insert clips, for shots where I have no other apparent way or suitable camera location to deal with the jerky motion (per AMC manual etc.). I would cut it in with my HD project.

My question is: how do I go about "uprezing" it, probably to cross-converted 1080i footage (having used the Miranda Bridge Dec to cross convert the 720p30)? Probably cant uprez it to 720p30, or I'd end up with the same problem.

Is there good software available to do this? I would prefer to capture with FCP, thus eliminating some of the timecode issues of aftermarket capture programs, and then convert the captured QT file.

Or should I just say NO to such shots?!

Thanks,

Gary Morris McBeath
SaltAire Cinema Productions
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Old September 17th, 2005, 12:15 PM   #15
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This is diverging OT: but, do you have the ability in FCP to bring SD into your HDV project and then in the SD clips properties select "scale to fit, keep aspect ration" and use Cubic-B spline as your scaling render method? FCP may have some method right in the program for you to uprez and select the scaling method. Here is a video example:

wmv format video

DivX format video

The original footage was shot on a DVC30 in 16:9 squeeze mode. Uprezed in Liquid 6 using Cubic-B spline and rendered Mpeg2 on the timeline. You could get better results if you select uncompressed but It's not that much better when dealing with HDV. Also some source material uprezz' better than others. DVC30 does not have 16:9 chips so there was loss to begin with in this scenario. I don't know what your original footage was shot on but your scaling method makes all the difference in the world when uprezzing.

If you're talking about 480 mode on the HD-100 you'll likely ge better results merely because the chips are 16:9. Give it a try and post some results, or you can post a 480 60P file and I can try it for you.

let me know...

Last edited by Stephen L. Noe; September 17th, 2005 at 11:07 PM. Reason: bad link
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