Ugly lines with DVCPro50 480 60i

obendega

obendega

Active member
This was shot on the HVX200 using DVCPro50 at 480 60i to the Firestore which was in DVCPro50 mode. Image stabilization was not on. Anyone have any idea what is causing those hideous jaggys???

Here is a still and a small clip:

http://hdcinemagroup.com/portfolio/DVCPRO50test.wmv


interlace.png




Thanks guys!
 
If you want "better" looking grabs from interlaced footage, you should either capture only one field or delinterlace the grab in post.

If you want better looking footage, then don't shoot interlaced.
 
Thanks for the responses guys!

I know that interlaced footage is going to have more jaggys then progressive, I just havn't seen it this bad before.
 
It can be much worse than this. Its all about temporal displacement. The more that your subject is moving, the bigger the displacement between the two fields.
 
Actually, this is a known "bug" with the HVX in all 480i 60i modes....DV25 and DV50. The CCDs are native 960X540 but in all modes, they are pixel shifted up to 1280X1080, then down converted. Somewhere in the chain, 480i footage ends up with terrible over-sharpened artifacts, there is no way around it. If you need the "live" look I recommend shooting 60P in 720P mode, then dumping to DV or downconverting with software.




ash =o)
 
I always wondered if a 'short way' would resolve a better image, if you end up SD and the native CCD resolution is almost close good for that, why uprez /green shift first?
Is a direct CCD reading and going to the DSP without the big uprez and downrez not a better deal?

There are over-sharpened artifacts on the border brown shirt - green screen.
 
I've shot in interlaced mode for nearly 30 years. This is not a normal situation for interlaced footage.
When shooting a scene with a lot of motion the BEST option IS 60i, except with the HVX.

I still love my HVX and promote it's virtues. BUT, this is a Bug. A very BAD bug and I hope to heck Panasonic sees it as that and tries to overcome it. They might not be able to and I will just have to live with it.

BUT THIS IS NOT NORMAL. I think Barry has confirmed this bug.

Still love the camera though! :thumbup:
 
Really ?

You mean there is the comb effect even if there is no movement ?

I never used the interlaced mode on my HVX...

I'll try to see what happens.
 
really?

really?

I thought this kind of stuff happened whenever watching interlaced video on a progressive display. I don't think it's a bug, but I can be wrong. I only have this camera. But have you tried to watch this footage on a interlaced monitor?
 
You can turn up the coring and down the detail to help mask it but it still wont look "good" This is an HVX only issue, it is not just normal interlace artifacting.



ash =o)
 
When I look at your clip on my CRT monitor I don't see any jaggs that an average viewer would see. Only if you look at the end of the blond hair (at the green screen interface) you see very very small jags but nothing to be worried about.


obendega said:
This was shot on the HVX200 using DVCPro50 at 480 60i to the Firestore which was in DVCPro50 mode. Image stabilization was not on. Anyone have any idea what is causing those hideous jaggys???

Here is a still and a small clip:

http://hdcinemagroup.com/portfolio/DVCPRO50test.wmv


interlace.png




Thanks guys!
Click to expand...
 
I brought this to Barry's attention in the first place, and I'm happy to see he has brought it general attention here.

Actually i don't see the problem on this particular clip, but its hard to evaluate over the web. The best way to see this problem is to focus on a thin contrasty diagonal line (a bright railing, edge of a window frame, bookcase, hot car roofs , etc) and movie the camera up and down over the diagonal. Jaggies will pop out at you if you have the right shot. If you don't have the right kind of image you may not notice anything.

These are the same artifacts that ordinary interlace always produces but more severe. You can really see the difference if you compare an HVX to a DVX in 480/60i. Then switch to progressive and they look the same.

Lenny Levy
 
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