Which VP's offer Gamma or colour balance control ?

[Mad Mr H]

Hi,

Which VP's offer Gamma or colour balance control ?

Of the ones that do offer these options what control do they offer? eg number of points etc.

Many thanks,

Andy.

[Gordon @ Convergent AV]

I'm sure if you download the manufacturers user manuals you'll be able to get this info. Lumagen, PMS, Optoma, Calibre, ABT are the main contenders to look at. Lumagen have more advanced stuff in development in Radiance than is in the current Vision range (or the beta Radiance for that matter). Obviously I am most familier with Lumagens implimentations. There paramteric greyscale and over all gamma adjustment is great, as is the colour decoder adjustment capability.

[Mad Mr H]

Ok, I start by going to the www.lumagen.com site.

I find the spec "paramteric greyscale and over all gamma adjustment"

But no manual that I can see on the site.

Any chance of some screen shots of this option?



I found "Pixel Magic Crystalio II" has 10-bit gamma correction with user-customizable gamma curve.

Thats sounds similar to the Lumagen gamma control - I will try and find a manual for that one.


The DVDO VP50 Pro - Output R/G/B Gamma - Found this spec so will try and find the manual for that as well.

The reason I asked was not to be lazy but a written spec does not always turn out to be what I expect.

(I bought a product with alpha blending thinking it was blending based options, turned out to be the way the menu was transparent so the video image could be seen through the on screen menu - I'm rying not to get caught out again )

As this is a fairly new area for scalers I did hope this thread would be able to show the different options available from each camp.

[Gordon @ Convergent AV]

Andy: The Lumagen gamma control is, I would say, superior to that in the PMS. Go to the Lumagen support forum and download the basic set up guide and advanced calibration guides to get an idea how it works just now. Also look at the faq's on Lumagens site as it'll likely have info about how it works and to use it. It's an 11 point adjustment on Vision series. It'll be 20 point on Radiance and Radiance also has gamut control system being implimented just now...and so far it rocks....

Also, rather than reading about what features a scaler or processor offers it is perhaps more important to ask or find out whether the advertised features exist....and if they actually function correctly or in such a way as to increase image fidelity......

Gordon

purely as an addendum. I have calibrated two plasmas in last week that have advanced colour management in them... The only part of all these features that I found useful and effective were the basic rgb greyscale adjustments..

oh and it's not a new feature for Lumagen. They had 5 point gamma and rgb greyscale as well as full colour decoder adjustments in their first Vision series product 6years ago....

[Mad Mr H]

I feel like I'm in a game !!!

I found the advanced calibration document.

"5. Fine tune the source gray scale using HDP’s 11 point adjustments.Now one can use the Lumagen multipoint calibration ability to flatten the grayscale output for this source input. See the Lumagen documentation for doing a 11 point calibration"

Yeah! I'm still looking for it !!!



And STOP THE CLOCK.......

http://www.lumagen.com/testindex.php?module=faq_vis

under the question about 2/5/11 point gamma correction........................

Thats what I wanted to know.


Now a LUMAGEN specific question if you don't mind................

As I understand 0 and 100IRE are fixed points in the system.

If I pick 15 IRE as a "parametric point" can I control the range this has an effect over ("Q" in audio terms) - could I pick 15IRE as the center of one parametric setting and that it would control points "X" IRE either side , where "X" is a user defined parameter ?

OR Does picking 15IRE change points either side 1-14 and 16-"Y" where "Y" is the next selected parametric point ?

I hope my question makes sense?


Does this parametric setting have an on screen visual overview of the correction curve , or a table of values or none of the above?

This does seem to be the best way of doing this and it does seem that Lumagen are more advanced with this than others.

[Mad Mr H]

One more Q.

Is this 11 points per colour?

So you have separate R G & B parametrics?


Or do you pick a reference colour (EG G) and a cut or gain would push toward B or R for instance ?


I am rather guessing here as I have not seen this system in use.


Its fun guessing but a little frustrating

[welwynnick]

Originally Posted by Mad Mr H

(I bought a product with alpha blending thinking it was blending based options, turned out to be the way the menu was transparent so the video image could be seen through the on screen menu - I'm rying not to get caught out again )

Andy, please don't tell me that bought a Crystallio 3800 thinking it could do edge blending with it's two outputs? I asked that question of PMS a long time ago and got told the HW wouldn't support it. There were rumours that something a little closer to home may do it in future.

Nick

[Mad Mr H]

Hi Nick,

Dont panic - I think Pixel magic will have go a long way for me to buy a product of theirs again..........

PS - HD SDI Sony S1 on route back to me so find time to pop round soon .

[Gordon @ Convergent AV]

Andy: Lumagen decide the "q" themselves based on how the points are adjusted I beleive so you have no control ovrer that.

POINT .. LUMA .. RED .. GREEN .. BLUE

15 ....... 15 ....... 15 ....... 15 ...... 15


Above is how the osd looks when you are doing the multi point gamma. You use the cursors to change the point value to what you want to adjust. This changes all values to right to same...ie if you wanted to do 82 then you'd change one of the defaults points to 82 and all other values would go to 82. Then to do greyscale you adjust the rgb values up or down to get what you want. This changes the LUMA value which will in turn change gamma if left uncorrected. So you go to the luma value and turn it back up or down to get to the original 15/82 value. The lumagen will alter the rgb relative value accordingly to keep greyscale correct.

Also the scaler reports on screen the actual value of the signal it is receiving. So if you have a crap dvd player you can see, ie 90 ire window dislayed at 82 ire for instance...in which case you wouldn't adjust 90 point you'd adjust 82 point as that is actually what is being recieved rather than what you think is being received.....

Lastly because you have control over this remap you could make in incoming 4ire signal be boosted to 6 ire for instance just by changing the luma value to right of the ppoint you want to adjust. So you can use this to alter the overall gamma shape. You need specialist tools to do all this stuff.

Lumagen have been asked to look at putting in a "knob" style gamma control and have said they will look at that. They have also said they are going to look at fitting the primary gamut adjsutment controls in to the Vision series early next year.

[Mad Mr H]

Originally Posted by Gordon @ Convergent AV

Andy: Lumagen decide the "q" themselves.......I beleive so you have no control over that.

Ok - It might be that you can control the "Q" to some extent, the points picked either side will decide the Q of that parametric - At least I am guessing that is how they do it.

POINT .. LUMA .. RED .. GREEN .. BLUE

15 ....... 15 ....... 15 ....... 15 ...... 15


Above is how the osd looks when you are doing the multi point gamma. You use the cursors to change the point value to what you want to adjust. This changes all values to right to same...ie if you wanted to do 82 then you'd change one of the defaults points to 82 and all other values would go to 82. Then to do greyscale you adjust the rgb values up or down to get what you want. This changes the LUMA value which will in turn change gamma if left uncorrected. So you go to the luma value and turn it back up or down to get to the original 15/82 value. The lumagen will alter the rgb relative value accordingly to keep greyscale correct.

That understands the relationship of different perameters, that is a clever system.

Also the scaler reports on screen the actual value of the signal it is receiving. So if you have a crap dvd player you can see, ie 90 ire window dislayed at 82 ire for instance...in which case you wouldn't adjust 90 point you'd adjust 82 point as that is actually what is being recieved rather than what you think is being received.....

This part is not only clever but also a fantastic checking tool .

Lumagen have been asked to look at putting in a "knob" style gamma control and have said they will look at that.

My opinion here is dont bother with the "Knob" style control system. A text box for actual numbers or up/down value system is best, the visual knob system might look pretty but in practice is awkward to use, this section is really for the pro's so the visual appearance is not as critical as the ease of use and accuracy of adjustment - Just my opinion.

[Gordon @ Convergent AV]

By "knob" they meant a gamma up down function, presumably with figures like 1.5 - 3.0 rather than a graphical "knob".