Official Low GOP topic, series 3

smsjr

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

driftwood

please

B3Guy

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

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...

smsjr

@FGCU what do you mean?

smsjr

@driftwood sent you a message regarding the file.

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.

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.

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.

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.

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

@LPowell, clear, technically accurate as ever!

Meierhans

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

RRRR

Interesting stuff.

driftwood

@No_SuRReNDeR, @cosimo_bullo, @lolo, @pchristoph, @B3Guy, @bkmcwd, @5thwall, @sohus, @thepalalias, @Hallvalla, @bdegazio, @lenuisible, @exilenorth, @RRRR, @FGCU, @sanzadez, @Bueller, @derek, @HillTop1, @shrigg, @sammy, @blackroom, @TrackZillas, @atticusd, @paglez, @filthy, @greenbean, @Nameless, @tuprware
@alcomposer

RE: INTRA SHOWCASE FILM
HI guys,
The only thing holding us up now is gettings the credits sorted:-
Please take a look at the text file on the collaboration thread to see if we have all your details correct -let me know by PM private message if I have to change anything.

http://personal-view.com/talks/discussion/1268/gh2-intra-demo-its-collaboration-time#Item_117

THANK YOU!

RRRR

@bkmcwd

I'm curious; if I should try out one of your patches, which should it be? (I'm sorry I haven't gotten around to it, although enjoying your flycam shots!)

Imaginate

@driftwood I just was out shooting some SEAQUAKE behind the scenes footage at western short film, outside campfire setting, it wasnt until I got home that I realized I had accidentally switched the camera in to 720p mode. I know this footage isn't as high res as 24p mode but can you explain the differences from 720p factory and 720p SEAQUAKE.

driftwood

720p driftwood is INTRA, and stock isn't. So better movement. Also higher average framesize/bitrate than stock so better for grading.

Hallvalla

Pretty sure factory settings couldn't pull THIS much detail out of the shadows - incredible. (just a sample of the detail hidden in the shadows – not an overall color grade)

Macalincag

Seaquake 720p is GOP 3, no?

Hallvalla

50p is GOP 1
60p is GOP 3

driftwood

60p at GOP1 is a f'in nightmare - thats y its gop3. Just as soon as it works for 720p60 it screws up 1080i60. This is because of the shared settings that would be great if they could be seperated in a future version of ptools (switching variables?) but VK has already mentioned that this would probably be not possible. Many people are preferring 1080i60 to have the best setting as they can pull out 30p from it.

proaudio4

@Imaginate
Damn that looks good!

Maybe I need to fire up some 720p60 and test this. Thanks for sharing. If there's a great improvement (which appears so based on your posted frame), this may look better for slo-mo dropped on a 24P timeline.

Ambergris

Driftwood, I bet there is a LARGE contingent that would love to see 720p60 GOP1 and does not care at all about 1080i60 use at the same time.

bkmcwd

@RRRR
Thanks! ;-)
First of all, I recommend this to you, although it is under improvement further now.
http://personal-view.com/talks/discussion/comment/25897#Comment_25897

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