Barry, do you confirm this?

P

pftricolor

Member
Hi Barry,

I came across this thread, "Ugly lines with DVCPro50 480 60i", and it kind of worried me, because as much as I prefer shooting progressive video, i still shoot interlaced. When i saw this kind of "jaggies" watching the footage on dvrack, I thought it was normal interlacing viewed on a progressive display.

Ashg said:
"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"

Tedrr said:
"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."

Do you confirm this?

I did a quick test: Shot some stuff with dvcpro50 60i and 30p. watching on dvrack the 60i footage had this lines (which I thought were just normal interlaced lines) and 30p obviously didn't. Then I watched both over the cameras component output on my tv. They were just fine.


So, is there really a problem with this cameras interlaced mode?

Another question, if the final product is standart broadcast will there be a perceivable difference between 30p and 30i? the diference watching over the camera's component output is pretty obvious.

thanks,

Pedro
 
Are you watching on a computer screen, or on an external monitor? Computer screens tend to show interlace lines that TV screens won't show.
 
BenB,

thats exactly the point I was making: the interlaced lines show up watching on dvrack and dont show up watching on my tv. The thing is that on the other thread I mentionened it was said that there was a bug with the hvx's interlaced modes (afaik there isn't) and that barry had confirmed it.

I'm just checking.

Thanks,

Pedro
 
I don't know of any bugs in the HVX. But I do know your computer monitor lies to you about the image. That's why you never judge an image on a computer monitor for color correction, interlace lines, etc.

I'm totally unaware of any interlace bug in the HVX. If Barry did confirm it, I'd like to know where HIS specific post is so that I can be aware of it, as I never shoot interlaced anyway, but do believe in learning your equipment.
 
That thread is completely *not* representative of what the HVX does. That looks like normal interlace artifacting.

But yes, the HVX is prone to stair-steppiness on its 480/60i. You can reign it under control by setting the detail level and v-detail-level to their lowest settings. It can look okay on many scenes, but on a lot of diagonal lines you'll really notice it. I'd vote for shooting 1080/60i if you really need interlaced; 480/60i from the HVX is aliased and stairsteppy. Nowhere near as bad as what that greenscreen shot showed though.
 
Thanks for the response Barry.

So do you think that if the final product is standart brodcast, it would be better to shoot dvcpro50 30p than 60i? How about dvcpro50 24p over 60i is it better as well (besides from the more filmish look, just talking about this aliasing stairstepping that you are talking about)?

Thanks,

Pedro
 
Progressive looks fantastic, interlaced looks jaggy.

The choice between 60i and 24p/30p is always one of: do you want the film-style look, or the "reality" look? If you want the film-style look, have no qualms, shoot away in 24p (or even 30p) and it'll look amazingly good.

If you want the "reality" look, you have to be careful with the HVX as it's prone to delivering jaggies in 480/60i. You could shoot in 720/60p or 1080/60i and downconvert in post and get excellent quality, but the 480/60i you've got to watch it to make sure it's not jagging out on you. Lowering the detail level and the v-detail-level can hide a multitude of jaggies.
 
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