Wednesday, June 16, 2010

CMS on a HTPC

I've been messing with video calibration stuff quite a bit recently and have managed to get vastly improved picture quality out of my projector/HTPC.  I know this sounds clich├ęd but I just didn't realise what I was missing!!  To get started all you need is a HTPC and a colorimeter (a device used for measuring colour), I have the EyeOne Display2 LT which is about £90.

I actually feel quite smug now because the JVC HD750 is almost the same projector as mine (HD350), but it comes with an integrated CMS (colour management system) and costs £2k more!  But now I can achieve the same results for no added cost.

Not only that, but it is also much easier to do CMS on the PC as you only need to take readings with the colorimeter, the CMS software calculates the adjustments automatically.  I've measured the pre/post results*1 and the results are excellent both in terms of measured accuracy and perceived viewing quality.  Also, it is nice to know your film is being displayed how the director intended...

There are a few different PC-based CMS methods to choose from:

  • MPC + pixel shader
  • MadVR renderer + yCMS
  • Upsilon Mixer


I've tried all 3, they all work.  They each have attributes that may appeal or alternatively push you towards another method.

MPC + pixel shader is simple to set up, it corrects white point to D65 and gamut (primary colour points (RGB) only).

If you are using MadVR then yCMS may be a better choice (over MPC + pixel shader) as it can also manage stepped gamma adjustments in addition to white point and primaries.

Upsilon Mixer should be the best, when released it will do full CMS, i.e.: it will adjust as yCMS but also secondary colours too.

So give it a go, it is like getting a new TV/projector!

*1: I use ChromaPure to measure the pre/post performance, this software is not free however there are free alternatives.

3 comments:

  1. This comment has been removed by a blog administrator.

    ReplyDelete
  2. The LT-1 meter gives you good results? No need for a color munki?

    greg

    ReplyDelete
  3. Overall results are excellent, however my LT is about 2 years old now and calibrated blues are now looking a bit indigo, I am looking to get a (pro/corrected) spyder3 next time.

    ReplyDelete