DispCAL speed

[Antonio Marcheselli]

Hi there

First, thank you for keeping working on this software!

I’ve realised the calibration (with 3D LUT) has become a little slower than previously. I’m running a media player on a Cherry Trail – based CPU. Yesterday it took 2+hours to complete and it was with fast settings.

As my 3D LUT file was not in the correct format, I thought I’d move the data to my i7 desktop PC, create the 3DLUT file there and then transfer it back on the media player.

Fair enough it’s an old i7 but it’s still an i7 and it’staken 15 minutes for processing the calibration and 3 minutes for the 3DLUT. is it just me or has the process become a little slow? I’m sure there’s a very good reason, don’t get me wrong, just wondering.

Is there a way to make it faster somehow? I know you are really not calibrating every day but just put yourself in my shoes: I made a mistake with the settings and it’s taking ages to re-process them again. And I’m confident I’ll have to do that again and again 🙂

Thanks for your help!

Tony

[Florian Höch]

I’ve realised the calibration (with 3D LUT) has become a little slower than previously.

The main thing that influences overall speed is measurement time (which depends on the instrument and the amount of patches), processing speed when calculating the profile and 3D LUT is usually only a fraction of that. If you’re only interested in a 3D LUT, make sure to use the XYZ LUT + swapped matrix profile type and only generate low quality PCS to device tables.

[Antonio Marcheselli]

Hi Florian

Thanks

The readings take the usual time, about 30m (i1 Display). Then my i7 takes 20m to process. My slower media player about 70 minutes. It’s definitely much slower than it used to be. Is that supposed to happen? I’ve noticed my main cpu running at only 15% when processing. ..

Thanks

[Florian Höch]

I’ve noticed my main cpu running at only 15% when processing. ..

Are you short on memory (RAM)? Excessive swapping to disk will definitely cause a slowdown.

[Antonio Marcheselli]

My desktop PC is a second gen. i7 with 8GB RAM and SSD.  The media player has an eMMC as main disk and only 4GB RAM. If disk is heavily used that explains the long time. But it does not on my main PC to be honest.

How long would you expect the data should take to process?

[Antonio Marcheselli]

Hi

An update. I’ve tried to profile my monitor using a fairly standard setup with “high” calibration speed and 425 patches. Indeed the final processing took only 2-3 minutes. The whole process took 19 minutes.

I need to find out what the difference is with the other calibration process though as the same computer took 20 minutes to process.

Question: why the 425 patches are split in two sessions, with a quick processing in between? Thanks!

[Florian Höch]

I need to find out what the difference is with the other calibration process though as the same computer took 20 minutes to process.

I gave some pointers above.

why the 425 patches are split in two sessions, with a quick processing in between?

The first batch is a pre-conditioning run. The subsequent batch of patches is laid out in a way that takes the display response measured in the first batch into account. This usually pays off as an accuracy advantage.

[Antonio Marcheselli]

Thanks Florian,

As it is taking so long on the little media player (90m vs 3m, and this is just final processing, reading time is the same) is there a way to skip the final processing process and have the files processed by the other computer? I tried stopping the process but it seems that only the LUT was then retained.

A Matrix calibration only (Curves + Matrix) is ok, only takes a few minutes to process the data. Problem is when the LUT is involved. I will try the settings you mentioned.

Thanks again!

[Florian Höch]

is there a way to skip the final processing process and have the files processed by the other computer?

Yes. Menu “Options” -> “Measure testchart…”, then transfer the measured chart over to the other computer and create a profile.

[Antonio Marcheselli]

That’s great thanks!

If I understand correctly I can do calibration on the machine and just read the testchart on my mediaplayer. Once completed I can process LUT and 3DLUT on my main desktop.

I guess this is the meaning of the message “the current calibration curved will be used” means? Use the current calibration (which must be done in advance) and then just read the colours for LUT and 3D LUT. Am I correct?

Thanks

Tony

[Florian Höch]

I guess this is the meaning of the message “the current calibration curved will be used” means? Use the current calibration (which must be done in advance) and then just read the colours for LUT and 3D LUT. Am I correct?

Yes. Although note that you don’t necessarily need to run 1D calibration if your goal is only a 3D LUT, i.e. in that case you can opt to use linear calibration instead, saving a bit of time.

[Antonio Marcheselli]

Thanks. Say my goal is a 3D LUT for madVR, don’t I still need a 1D calibration to be embedded in the LUT file? How do I select linear calibration only if I wanted? Is that what you suggested above: XYZ LUT + swapped matrix profile type and only generate low quality PCS to device tables?

Thanks

[Florian Höch]

How do I select linear calibration only if I wanted?

In the dialog “the current calibration curves will be used” you can choose to use linear calibration instead.

[Antonio Marcheselli]

Thanks. I’ve done as you suggested but DisplayCAL wants to create the profile after reading the testchart. How can I prevent that from happening?

[Florian Höch]

If you’re using “Auto” testchart, an intermediate pre-conditioning profile will always be created. This is normal and not unexpected.

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