Magic Lantern Forum

Using Magic Lantern => Hardware and Accessories => Topic started by: st599 on June 05, 2015, 12:52:46 PM

Title: HDMI out with LUT
Post by: st599 on June 05, 2015, 12:52:46 PM
Hi,

I'm interested in outputting video to a local mixer but require a non-standard video transfer function (i.e. not ITU-R BT.601, ITU-R BT.709 or ITU-R BT.2020).

Is there a way to output a clean feed of the sensor with a LUT altering the output in ML?

Happy to try and write a module if not.  Does anyone know the colour space of the sensor output that I would need to transform from?

Simon
Title: Re: HDMI out with LUT
Post by: Andy600 on June 05, 2015, 01:26:35 PM
No chance.

The closest you will get is using a 5D mark III for clean HDMI 4:2:0 and a picture style (basically an ICC profile) but picture styles are non-linear and not invertible. Cinestyle is 8bit log and can be inverted well with cineon tools but there is still a non-linear lut in there (Canon Standard).

You can work out the chromaticity and white point xy values of a specific camera from the color matrices found in a DNG (converted with Adobe DNG converter). You'll need to multiply the inverted and transposed XYZ D50 to Camera native RGB color matrices (2 solved for each sensor under A and D65 illuminants) by the Canon white balance coefficients (in a 3x3 matrix) plus chromatically adapt the white point from D50 to D65 before you even get started trying to linearize the actual picture style - all in 8bit i.e. there is little point even trying.
Title: Re: HDMI out with LUT
Post by: Sunshinegirls on July 10, 2015, 09:00:41 AM
You can contact HDgenius' customer service http://goo.gl/VvdeuX ,they can give you a satisfied reply.
I met a similar problem last week and they solved it.