Digital Cinema Package

[M Most]

I'm affraid there is no GUI for DCP-making with colorspace correction, for now.

Sure there is, at least for the colorspace conversion part. It's called Adobe After Effects. But it's not open source.

[Thrane]

I'm using After Effects for making a tiff sequence, but again, the problem is the wrong colorspace.
What are the correct settings to get the CIE XYZ as output?
If thats what I need?

[M Most]

I'm using After Effects for making a tiff sequence, but again, the problem is the wrong colorspace.
What are the correct settings to get the CIE XYZ as output?
If thats what I need?

Without going through things step by step, read the Adobe white paper on color management in After Effects. It tells you everything you want to know.

[Pavel Klepinin]

I'm using After Effects for making a tiff sequence, but again, the problem is the wrong colorspace.
What are the correct settings to get the CIE XYZ as output?
If thats what I need?

You can save your clip as tiff sequence using X'Y'Z' colorspace, and then use OCT GUI to biult dcp. Check some first pages, there was a correct advice.

[Eren Ozkural]

Just read the walkthrough...this is seriously one of the coolest posts I have ever read on REDUSER Leerafel. Well done.

I especially like the fact that I have everything I need at hand beside the Easy DPX license.

Now, to find a booth manager in London whose feeling generous...

[Priit Poldmaa]

Doing here my first conversions to DCP for a local indie feature.
Got my first pakage with Opencinematools today.
Wolfgang, Pavel, Chris etc have given an invaluable information here.

But one aspect worries me.
With the ImageMagick sample the conversion is from sRGB to X'Y'Z' P3.
-gamma 0.454545 -recolor "0.4124564 0.3575761 0.1804375 0.2126729 0.7151522 0.0721750 0.0193339 0.1191920 0.9503041"

What coeficents shoud I use if the source is Rec.709?
Got the original as BlackMagic 10-bit uncompressed video and converted to DPX files with Combustion. Gamma was left as original.

Thanks
Priit

[Wolfgang Woehl]

priitp,

see http://github.com/wolfgangw/digital_...-xyz_matrix.rb for the exact numbers and source code to check those numbers.

[Priit Poldmaa]

Thanks Wolfgang.
Have see it earlier but forgot already.

What about gamma?
As Rec.709 gamma has a linear part it is not so easy to deal it with Imagemagic convert -gamma.
Let's say we use one value for gamma but what might it be?

I remember Michael Most wrote somewhere that "Rec709 is described as having a specific gamma that is somewhere around 2.3 or so (but not exactly, the lower end of the curve is a bit different)"

So will this be the best bet? -gamma 0.434783

It seems to me it would be good to have a 1D LUT for linearisation.
I have to check the -clut possibilties.

Priit

[M Most]

I remember Michael Most wrote somewhere that "Rec709 is described as having a specific gamma that is somewhere around 2.3 or so (but not exactly, the lower end of the curve is a bit different)"

I might have said that, and it's not inaccurate. The real problem with Red709 is that there is no definition for a reference display, in fact, there is no display definition at all, as opposed to, say, the DCI P3 specification. I'm told Charles Poynton is currently working on trying to rectify that, among other things.

[Priit Poldmaa]

Thanks Michael for the input.

Unfortunatelly ITU Rec.709 standard is not freely available.

From Cine-tal forum here found this formula:
-----------------------------------------------------------------------
Overall opto-electronic transfer characteristics at source:

V = (1.099 * L^0.45) - 0.099 for 1 ≥ L ≥ 0.018
V = 4.5 * L for 0.018 > L ≥ 0
where:
L: luminance of the image 0 ≤ L ≤ 1
V: corresponding electrical signal
-------------------------------------------------------------

Not sure how reliable is this source.
Meaning to make a -clut image based on it.

Priit