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Old March 26th, 2006, 04:08 PM   #1
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Artifacting normal on HD100

I am about to send the cam to the rep. because of quite hevy SSE. But I am wondering if the artifacting that you can see on the image is normal? Do you get those big blocks when filming the sea?

Its filmed in 25P and captured with Aspect HD

http://www.plonk.se/testpic1.jpg
(176kb)
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Old March 26th, 2006, 04:20 PM   #2
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It seems that you've found the limitation of the HDV codec.. Good enough for a lot, but not for things like heavily moving water or waving trees..
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Old March 26th, 2006, 04:33 PM   #3
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Uhm, no that doesn't seem quite normal. I've had the GY-HD101 for about half a year now and filmed a lot of similar things. That kind of bad image never occured with me. If I saw it, I'd think it would be abnormal...
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Old March 26th, 2006, 10:37 PM   #4
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I've shot material with similar fine detail, as have other in this forum, and not seen macroblocking like that.

I'd also, from the good words I hear about Aspect HD, would guess it's not strictly from that either.

Is it possible there's yet another layer of recompression happening somewhere in your flow?
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Old March 27th, 2006, 02:31 AM   #5
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Quote:
Originally Posted by Nate Weaver
I've shot material with similar fine detail, as have other in this forum, and not seen macroblocking like that.

I'd also, from the good words I hear about Aspect HD, would guess it's not strictly from that either.

Is it possible there's yet another layer of recompression happening somewhere in your flow?
It is not from the jpg-recompression of the image, you see the same macroblocking on the clip in the program-monitor in premiere.

Anybody with samples of the sea?
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Old March 27th, 2006, 03:11 AM   #6
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Here is another picture (a more butiful one) where you can see what happens when the sea is moving compered with the rock.
http://www.plonk.se/macroblockinghd100ecineform.jpg

Note: The camera is not moving at all.



Is it somthing wrong with my cam or is it souposed to be like this?
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Old March 27th, 2006, 04:13 AM   #7
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Quote:
Originally Posted by Mikael Widerberg
Is it somthing wrong with my cam or is it souposed to be like this?
There's nothing wrong with your camera; what you're seeing is what HDV does.

Here's another example, ducks on a lake, that shows the same type of artifact. It's a pixel-for-pixel extraction from the 1280x720 frame.

http://www.icexpo.com/HD100/TwoDucks-1.JPG

Rippling water is tough for HDV to cope with; there's too much changing all over the place for the motion prediction to handle. If you're shooting in 24P mode it'll be a little more resistant to artifacting than it would be in 30P mode. It's also dependent on how much of the frame is filled with moving water; if it's a small portion, then HDV copes much better, but if the moving water covers most of the frame, that's a lot more challenging for it to deal with.
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Old March 27th, 2006, 06:15 AM   #8
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Quote:
Originally Posted by Barry Green
There's nothing wrong with your camera; what you're seeing is what HDV does.

Here's another example, ducks on a lake, that shows the same type of artifact. It's a pixel-for-pixel extraction from the 1280x720 frame.

http://www.icexpo.com/HD100/TwoDucks-1.JPG

Rippling water is tough for HDV to cope with; there's too much changing all over the place for the motion prediction to handle. If you're shooting in 24P mode it'll be a little more resistant to artifacting than it would be in 30P mode. It's also dependent on how much of the frame is filled with moving water; if it's a small portion, then HDV copes much better, but if the moving water covers most of the frame, that's a lot more challenging for it to deal with.
Is this good or bad news, I dont now?

Huum, 70% of the Earth is coverd with water, didnt the JVC peapole now that?
Do you peapole agree on this one, Is HD100 sopoused to be like this?
Hmm, I ges big waves are better than the small ones.

Well, maybe I dont have to send it to the rep. then, and I will be saving some monye.
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Old March 27th, 2006, 08:26 AM   #9
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Well - I have to say that there are some artifacts on the edge of the arm of one person. I really have never seen an image thjis bad from a HD100, defenately not mine... although I've shot similar things with lots of moving fine details. I'd say it is somewhat worrysome and perhaps you should ask the rep (or the JVC techs) if that's normal.
Is it just a few frames with such bed artefacting or is it constantly like this (in this shot obviously)?
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Old March 27th, 2006, 08:31 AM   #10
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Quote:
Originally Posted by Mikael Widerberg
Is this good or bad news, I dont now?
Well only you can answer that question. On the plus side, the chances that viewers will notice the MPEG artifacts while watching your video in motion (emphasis on MOTION) are extemely low. While an editor sees every frame and srutinizes every pixel, the viewer just won't look at it like that.

By the way, I think the worst thing I've seen was some footage on CNN playing in one of the smaller "boxed" videos next to the news caster. It was night time footage of George Bush getting off Air Force One. There were photographers all over taking flash photos. I'm pretty sure the videographer was using something like a Z1, because every time a flash went off the MPEG2 broke the whole image down into giant blocks. The image changed so much from the dark frame to the lit frame that the real-time encoder just died. Too much change within a GOP is just not ideal for HDV, its just the trade off to shooting generally great quality HD video on $5 tapes.

Anyway, back to your water footage, perhaps you should screen it for some of your friends or family on an HD set and just ask them how they liked it. I bet you won't hear a single complaint about artifacts in the water.

www.philipwilliams.com
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Old March 27th, 2006, 08:45 AM   #11
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To me it al just seems to be normal HDV compression. People who claim to have better examples in the same conditions, can you post some stills here? I'm very interested in the differences.
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Old March 27th, 2006, 12:20 PM   #12
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I will test

Mikael,

If the weather/wind cooperates, I will go to the water today and make some test footage and then post some shots on my site later this evening
I will make the same shots in both 24 and 30p for a comparison

I shoot at minimum detail almost exclusively regardless of subject, yet today I will make some shots at higher detail to see if I can create shots similar to what you have posted - I will record all camera settings and equipment used
as well as time of day and available natural light description

cheers
Pete
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Old March 27th, 2006, 02:08 PM   #13
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Quote:
Originally Posted by Peter Dolman
Mikael,

If the weather/wind cooperates, I will go to the water today and make some test footage and then post some shots on my site later this evening
I will make the same shots in both 24 and 30p for a comparison

I shoot at minimum detail almost exclusively regardless of subject, yet today I will make some shots at higher detail to see if I can create shots similar to what you have posted - I will record all camera settings and equipment used
as well as time of day and available natural light description

cheers
Pete
Glad to hear that! It will be very interesting to see the result. I will do some testfilming as well.

Vincent, do you get the same result with your new Canon?
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Old March 27th, 2006, 02:20 PM   #14
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Hmmmm...... Mikael quick question. Philip mentioned seeing footage on CNN that "broke" when trying to adapt to light changes caused by flash bulbs. I noticed a large area of white in your jpeg... perhaps the shimmer off the water had the same effect as the flash bulbs. Could someone shoot the same scenario with an ND grad to prevent the water from clipping and see if you get the same macro-blocking?

Thanks.

Tim
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Old March 27th, 2006, 03:30 PM   #15
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Most anything seen "broadcast" these days has MPEG2 encoding much more drastic than what the HD100 does to tape. Digital cable is MPEG2, as is digital satellite.

I see MPEG2 artifacts at home on every channel I receive!
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