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Old January 9th, 2006, 01:46 AM   #1
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image motion separation artifacts ( w example)

I downloaded some hd100 clips from
http://www.dvxuser.com/V3/showpost.p...67&postcount=1

The shot of the guitar had a disturbing artifact, the details on the guitar neck move with independent motion from the surface they are attached to!
It's an mpeg motion estimation error, ofter seen on lower bit rate DSS tv broadcasting.

I cropped out a 640x480 from the clip, blew it up, and slowed it down a bit.
Objects slip slide over the dark brown wood. Logo decal, and the shiny parts. Otherwise very nice footage!

See the cropped example:
http://www.pixelharvest.com/hd/shake.m2t

-Les
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Old January 9th, 2006, 02:34 AM   #2
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You describe the effect and its cause well. Its the first time I've seen any artifacting from 720 so I've got to ask - was the motion filter ON?
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Old January 9th, 2006, 03:43 AM   #3
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Someone posted some footage of a dance show that showed some compression artifacting.

2 guys were swinging firworks around their head sending sparks everywhere whilst the cameraman zoomed out - i.e. about as tough as it gets for HDV. The artifacting was there, but the scene was so dynamic that it helped masked the problem. In generally ProHD seems pretty robust.
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Old January 9th, 2006, 06:21 AM   #4
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Quote:
Originally Posted by Mike Marriage
Someone posted some footage of a dance show that showed some compression artifacting.

2 guys were swinging firworks around their head sending sparks everywhere whilst the cameraman zoomed out - i.e. about as tough as it gets for HDV. The artifacting was there, but the scene was so dynamic that it helped masked the problem. In generally ProHD seems pretty robust.
I posted this footage. It was captured with HDlink (mid-setting I found out later) And motion smoothing was ON. That could help the small artifact or not, I don't know.
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Old January 9th, 2006, 06:43 AM   #5
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Quote:
Originally Posted by Marc Colemont
I posted this footage. It was captured with HDlink (mid-setting I found out later) And motion smoothing was ON. That could help the small artifact or not, I don't know.
Thanks Marc,

Do you mean it had been recompressed when captured or was that the natives files from the tape?
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Old January 9th, 2006, 07:45 AM   #6
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I didn't know before that there was a capture setting in HDlink until last week.
Maybe a question I should to post in the Cineform forum to know exactly what these setting do to the captured image. Unless David from Cineform reads this post.
This week I will re-capture that footage again in the highest setting to check if I see differences...
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Old January 9th, 2006, 08:27 AM   #7
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Quote:
Originally Posted by Marc Colemont
I didn't know before that there was a capture setting in HDlink until last week.
Maybe a question I should to post in the Cineform forum to know exactly what these setting do to the captured image. Unless David from Cineform reads this post.
This week I will re-capture that footage again in the highest setting to check if I see differences...
How are you finding the camera? Have you had any issues with the codec (or anything else serious)?
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Old January 9th, 2006, 08:57 AM   #8
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Very cool how you found that!

I post those m2t's raw so you get what I get. It's funny how when footage get's posted, it becomes a "where's waldo" for errors. The sloppy camera motion is me monkeying with a cheap Libec M20. At regular reslution this minute slippage goes un-noticed unless you are looking for it with excrutiating detail.

Motion smoothing was on BTW for that shot.
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Old January 9th, 2006, 09:55 AM   #9
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Quote:
Originally Posted by Mike Marriage
How are you finding the camera? Have you had any issues with the codec (or anything else serious)?
I don't have the long term experience yet, but yes I'm very happy with the camera. The shot I took were the the guys are playing with the pyro sticks is probably one of the most worst cases for the HDV codec to shoot.
I don't have an expensive HD-monitor, on my Laptop the result looks very good. At the same time another guy was filming the same thing with a Sony FX1. I bet his interleased video looks worse when you pause.

When I just bought the camera I had issues recording video. The JVC support promply replied the same day on my email to them to clean my heads. I'm a bold guy so I went strait to the bathroom to soap my head (just kidding).
After running the cleaning tape it works just fine. I saw afterwords on other forums that I was not the only one which needed to clean heads before usage. It was with different brands too.
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