Originally Posted by Scott Wilkinson
I believe I misspoke a bit here. Of course, all LUT boxes are simply containers to hold the data fed into them by the LUT software. My question is, what LUT software has the capability to bypass or ignore the neutral axis in a 3D LUT? I know that CalMan does not, but perhaps other programs do and I'm simply not aware of them.
has said, Lightspace (I believe from HTP license upwards) has "LUT math" functionality. This allows you to generate a standard 3DLUT, save out just the 1D greyscale portion, and subtract the 1D from the 3D to leave a LUT which ignores the neutral axis. I'm not sure this would address banding anywhere outside of the grey axis, and the examples I have of LUT induced banding tend to be outside of the grey axis.
Your experience of banding during your review may have been relatively benign because you are using a high-end colorimeter which is way outside of affordability for most enthusiasts looking to calibrate one or two of these TVs. From looking at a few LUTs generated in Calman they appear quite "noisy" - it looks like it relies heavily on the precise co-ordinates of individual measures in the generation of their LUTs, so improving the quality of the profile using a high-end meter would be one way to reduce their noise making it into the output LUT. Another way would be for the LUT engine to employ more smarts in ignoring or smoothing out measurement kinks, or to have options for "relaxing" the shape of the LUT later.
It would have perhaps been interesting to use an entry level unit such as the C6 or i1d3 which would perhaps be more representative of the typical Calman user's toolchest. As it is your results are probably going to be a poor match for what most will see.
Originally Posted by nezil
Although I've been an AVS Forum member for many years, I very rarely comment on threads, mostly because I work for a manufacturer, and it's very easy to end up being considered the customer support for forum users.
The reality is that I don't work for marketing or PR
; I'm an engineer, and I was the architect and project manager of the autocal feature on our TVs. Scott reached out to me for some additional information for his article, and I was happy to provide it.
Hi Neil, I hope you can take the following feedback in the spirit in which it is meant, which is constructive insight to my own purchasing rationale.
For me personally the decision to only support Calman is stopping me buying the new family of LG units. I'm heavily invested in 3DLUT, with a Radiance Pro for my main theatre, small 1080p 3DLUT box for the TV in the lounge, and Lightspace HTP + various meters (BasICColor Discus, i1pro2, i1d3). I'd dearly love to have a 4K 3DLUT for the set in the lounge, which would make me upgrade it. But I'm not going to buy a Radiance Pro for that TV which is mostly occasional non-critical viewing. And I'm not really up for spending hundreds of dollars on software which I see as being unnecessary to me (and by the looks of it, not as performant as what I already use).
At the moment I'm going to be waiting to see what the next Panasonic releases are doing with respect to this feature as they do allow import of 3DLUT created via Lightspace.
While I accept there may be commercial reasons in place for you being tied to Calman, I can't think of any good technical reasons. 3DLUT has a lot of smarts going into generating the LUT, but isn't technically a complex thing at the upload stage. The extent of the API support added for LUT upload and control manipulation appears to just be a few extra commands added to the standard LG webOS websockets API, which already has several open-source implementations out there on the interweb.
Ultimately I imagine LG are in the business of selling TVs and not calibration software - opening up your API to allow users of other commercial packages such as Lightspace and Chromapure, as well as the excellent free ArgyllCMS/DisplayCAL, can only help you sell more product and improve the image of your company and products.
On a slightly related feature point - seeing as you have a powerful SOC in the box, it does seem ludicrous to have to use an external pattern generator (at very significant cost if DV generator capability is required) when you could generate and display the patterns internally. I guess you may have done this to minimise your own development efforts, but it would be really great not to have to rely on an extra external box to set up the 3DLUT.