Official Low GOP topic, series 3

Meierhans

@LPowell "color space is digitized linearly" Lets hope we can get around this one day with custom curves pre 8 bit conversion.

alcomposer

@LPowell, clear, technically accurate as ever!

LPowell

@alcomposer
The combinatorial gamut of colors in the 24-bit YCrCb color space is deceptive. The color space is digitized linearly rather than logarithmically as the eye perceives light intensity. As a result, there are far too many discrete colors in the bright end of the color space and far too few in the dark end. This is why banding occurs frequently in dimly lit gradients of the sky at dusk or dawn. In these circumstances, the best way to avoid banding is to expose to the right of the histogram, while making sure that you don't blow out too much of the highlights.

alcomposer

@RRRR, @5thwall, 8 bit allows 16,777,216 different colours. The human eye can see a peak of 10,000,000.
This has been discussed before... The reason why I have posted in 'low gop topic' is that a few users have noticed possibly different amounts of banding on different PTool settings. This may point towards something in PTool that can fix this.

Quite possibly the issue is 8bit, but after reading the forums on P-V that discussed this I doubt it. Maybe @driftwood or @VK could elaborate on this? (or @LPowell, @cbrandin).

Forgive me if I missed off any other 'power' posters.

Meierhans

I had to find out that Magic bullets denoiser (yeah, this ugly sucker that always crashes..) can be abused to get rid of banding in flat areas like sky. If you don´t want to denoise the rest of the picture to much you trow a chroma key onto it or mask it.

RRRR

Re: banding.. I get that it's easy to get problems when downsampling but - there really is no way 8 bit color can cover all the colors one is trying to shoot. Smooth gradients always are troublesome, but it seems like some more than others - for me white walls indoors are always troublesome. Skies are better dealt with, though it can be a nuisance in some circumstances when a spectacular sky is turned into patches of color..

Indoors - artificial lighting (not professionally lit scene) and shallow dof is often a recipe for banding, especially if using nostalgic -2 x 4.

5thwall

@alcomposer 8bit helps but I've seen banding even in Apple's Uncompressed Codec at 8bit. 10bit is best. You really have to take into account the codec compression and the chroma subsampling. GH2 is 4:2:0 so you are at a color-loss disadvantage as there is a lot of color that is not getting recorded to the file. My guess is there's no way around it with the current codec and the chroma subsampling rate.

smsjr

@driftwood sent you a message regarding the file.

smsjr

@FGCU what do you mean?

alcomposer

@ALL I thought that it was concluded that 8bit did 'not' introduce banding and that 8bit has enough information to describe the scene without any artifacts? I am not convinced that this is an 8bit issue... Kind of really needs to be sorted out, can't be compared to RED with banding!!! :-(

Looking at the AF100 forums for banding issues,... users seam to be very happy with its performance, stating that "pointing the AF100 at a very bright light may cause this, but even then not so much". So this is a testament to 8bit and no banding. Hopefully if this is a problem there are some PTool patches that dial it down... right down...

B3Guy

@Driftwood just shot with seaquake all day today, absolutely zero issues. Once again, freaking brilliant.

driftwood

please

smsjr

@driftwood tripod. I can upload a sample tomorrow. I assume you want mts file correct?

driftwood

@smsjr out of interest were you tripod or handheld? And can you post the file to me?

smsjr

@RRRR Banding typically occurs when you go from higher bit depth down to lower bit depth. For example a 12-bit image to an 8-bit. Generally adding some dithering helps with minimizing that banding. So, perhaps something is going on with the downsampling in camera that is contributing. I'm just trying to benchmark when it will most likely occur so I can plan for it.

smsjr

@driftwood Shot at ISO320 (made sure to go from higher ISO back to 320), shutter 50. shot on a Tokina 11-16mm wide angle lens (only lens I had on me) at 16mm. Had an ND3 on it. If I remember correctly I was somewhere around an F4. Profile was Smooth with everything dialed down to -2

I'll try to simulate a similar look and test again to see what I get with various settings.

TrackZillas

@bwhitz please do can't wait..

RRRR

@smsjr

Banding is an issue related to 8bit color (As far as I know), and in my opinion it becomes even more obvious with driftwoods latest patch, in some situations. (white walls, flat coloured surfaces..) Is it a reason not to use the patch? Hell no, what one must do is take care to avoid it when shooting. Correct exposure and then change picture profile in the camera if you absolutely need a shot with a problematic area.

Id be very interested in what experience people have from using some sort of diffuser filter to avoid banding, though!

driftwood

@smsjr what settings were you using, iso shutter, etc...

smsjr

@driftwood Looking at some test footage yesterday I found there is still banding issues. This was with SeAQuake. Was a plain wall that was showing the banding. Is this something that is still with us or should I really not be seeing this in these latest patches?

In the meantime, I'm also looking at the chain, as this was done in 5DtoRGB to see if anything is being introduced there.

Also, what is the current software recommendation for checking bitrates? 5DtoRGB was reporting video to be around 143mb/s which I'm guessing is because these were locked off shots with no movement in the frame.

Thanks!

bwhitz

@astraban

Sorry... don't have finesse. :(

Anyways, this could probably be it's own topic, so I'll go start a new thread to keep this one clean.

astraban

@bhwitz after effect+finesse ftw ;-)

disneytoy

I have some good Tutorial info here "DaVinci Resolve 8.1.1 Lite, DNxHD and GH-2 footage"

http://www.personal-view.com/talks/discussion/comment/26370#Comment_26370

With Resolve 8.1.1 lite being free, Now unlimited grading nodes, and no longer a $500 license to use it with DNxHD its a very high end solution for GH-2 footage. Look for a Windows version early next year.

bwhitz

@atticusd "if you don't make that "GH2 Intra grading tutorial" cute little kittens will start to drop dead all over the place. Are you sure you can live with that burden?"

I can live with that burden... I just don't want to let you guys down. haha.

Anyways... I've never done a tutorial before, so I'll have to do a few tests with screen recording software and such first. But then I'll be good.

Oh, BTW... what are most people using for grading? I can do it in FCP, FCPX, AfterEffects, and maybe Davinci Resolve (but I'm still learning it myself).

JDN

@whitz +1

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