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-   -   Stuttering Picture ifrom V1E in 25p mode (https://www.dvinfo.net/forum/sony-hvr-v1-hdr-fx7/92367-stuttering-picture-ifrom-v1e-25p-mode.html)

Owen Carey Jones April 25th, 2007 08:24 AM

Stuttering Picture ifrom V1E in 25p mode
 
I have read a lot of what has been posted here about the poor picture from the European version of the V1 (the V1E) but so far have not seen anything about the problem I have encoutered.

I bought my V1E a couple of months ago and it has now been back to Sony Prime Support twice. The first time they fixed the soft picture issue (seems to be a standard repair) but not the stuttering picture, which I had told them about. When I re-tested the camera in 25p mode on its return to me, I found the picture still stuttered whenever I panned or tilted or zoomed as it had done before it went back to Sony. In other words, move the camera and the picture becomes totally unusable, trees "walk" across the screen in little steps, as does everything else in the picture.

The second time it went back to Sony, with a tape showing this stuttering effect which happens whether you play it on the little built in LCD screen or via output to an HD monitor using HDMI, component or composite outputs. I use a BenQ mode FP241WZ which is a true HD monitor capable of displaying 1080p but it's just the same if I play it to a TV via the composite output.

Sony sent the camera back the second time saying that it was performing according to spec and that there was nothing wrong with it!

Can anybody shed any light on this problem. It's not a minor thing it is a really severe stuttering. Am I doing something wrong? Is it as simple as changing a setting? If I can't find a solution, I will not be able to use the camera in 25p mode.

I hope someone out there knows the cure for this problem.

Owen

Piotr Wozniacki April 25th, 2007 09:31 AM

"Stuttering" can be attributed to how we perceive the 25p motion and is normal (isn't camera's fault); not having seen any of your clips I can't be sure if this is what you mean.

Owen Carey Jones April 25th, 2007 10:19 AM

Yeah, that's what Sony said. The thing is, if I went to see a movie and it looked like my 25p footage does, it would make me feel physically sick after about 30 seconds, as my footage does. No one would be left in the cinema after two minutes so I don't think what I am getting is normal, regardless of what Sony say - it is unwatchable in the truest sense. I shot a lot of super 8mm film thirty years ago which I project at 16 fps and that is more watchable than my 25p footage from the V1.

Bob Grant April 25th, 2007 03:09 PM

Quote:

Originally Posted by Owen Carey Jones (Post 667208)
Yeah, that's what Sony said. The thing is, if I went to see a movie and it looked like my 25p footage does, it would make me feel physically sick after about 30 seconds, as my footage does. No one would be left in the cinema after two minutes so I don't think what I am getting is normal, regardless of what Sony say - it is unwatchable in the truest sense. I shot a lot of super 8mm film thirty years ago which I project at 16 fps and that is more watchable than my 25p footage from the V1.

So ask yourself this, what is abnormal about what you're getting.
All a film or video camera has to do is record x pictures / second, in this case 25 per second. What could a camera do to mess this up? Assuming it might be doing what it's meant to do the next question is what could you be doing to mess up the motion at 16, 24 or 25fps.

Several things are quite important.
Shutter speed / angle. Anything faster than 1/50th / 180deg and you can easily have problems.
How you move the camera. Locked down, tracking or panning with a subject is the answer. THe HDV codec can make this even more vital than with film.
How you view the footage. If the monitor is doing the wrong thing your perfectly good 25p can get very stroby.

Also viewing conditions. I bet you watched those 8mm movies with the lights out.

Owen Carey Jones April 25th, 2007 04:22 PM

Thanks for your replies, guys. I'm really grateful for any insight on this and I think, and hope, I'm up for being convinced that it is me that's doing something wrong. In fact, I'd love to find out what that is.

Having said that, one thing I don't understand is that if what I am seeing is normal and to do with the HDV compression, why doesn't it happen on the 1080i picture as well. Surely if the problem is to do with compression, it would happen with both interlaced and progressive modes. One of the things Sony told me was that what I was seeing was the result of long GOP. Again, then why doesn't it happen with the interlaced picture - that is also compressed using long GOP.

And let me reiterate, we are not talking about a small difference between the interlaced and progressive modes, a picture which is a little less smooth on the pan, the difference really is huge.

If nobody else has experienced it, then it probably is my camera. I think what I need to do is hire in another V1E and see if it has the same problem. If it has, then clearly it is me that is stark raving mad. If it doesn't, then maybe Sony are being a little disingenuous.

Steve Mullen April 25th, 2007 04:47 PM

Of course there could be still be a problem with your camcorder, but Given its been to Sony twice and your description of what you see -- you are seeing low temporal-rate capture. I don't like it -- and obviously neither do you. Simple solution, shoot 50i. There's no reason to shoot video which doesn't look good.

I'd also confirm that you are using the -- locking -- the correct 1/50th shutter-speed. i suspect you may not be doing this.

Marcus Marchesseault April 25th, 2007 04:58 PM

I don't like low framerate and it seems I'm not alone. I think 24/25P is only acceptable because of strict operation guidelines by cinematographers. Nobody is using 4-pound film cameras to shoot big-budget movies. They use physically large cameras with smooth cranes, dolly tracks, and steadycams that all dampen jittery motion. Pans are kept below or above the speeds that make the stuttering more obvious. I notice framerate problems at certain times in almost every movie I see.

From playing video games, I know that I can't track motion as effectively if framerate falls below about 30fps. 24fps is clearly too slow for my brain to keep dramatic motion trackable. 40fps, like that in IMAX, is noticeably better than 30fps and 60fps is absolutely perfect. I can notice strobing at 60Hz on a CRT monitor, but an LCD doesn't strobe like that so 60Hz is fine for anything but CRT.

Owen Carey Jones April 26th, 2007 08:59 AM

Thanks Steve, I did try a 1/50th shutter speed (I had read about doing that somewhere else) but it didn't really make any difference. I think you're absolutely right - just shoot 50i and forget about 25p. With more and more digital screens becoming available in cinemas it is entirely feasible to do so and still get a theatrical release as I did with my last feature which was shot 50i (I think) using a Sony HDW 750 and looked gorgeous when projected onto a cinema screen.

Thanks to you too, Marcus, what you say makes a lot of sense, especially about keeping pans and tilts as slow as possible - I'll try that.


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