Color saturation

[dark.soft]

I encoded Matrix Revolutions in Xvid with virtualdubmod, and I had no problems with the quality, but I'd like to reproduce the nice color saturation improvement that uses PowerDVD's CLEV. How can I do that? Using the HSV filter? I hope that there is a better solution!

[Guest]

Are we supposed to guess what your criteria are for "better"?

[dark.soft]

Well, I'll tell you. For "better" I mean a filter wich optimizes colors just like the clev. For example, there was a scene in Resident Evil in an elevator with only blue light. With PowerDVD the colors were more saturated but the details on a character's white shirt were still there. With the hsv filter, in that scene the details were deleted by the more intense white tint of the shirt. Do you understand now? If you don't, I'll try to explain better :). Thank you!

[trevlac]

CLEV(TM) - CyberLink Eagle Vision Technology

Even though the LCD market is gaining over CRT, its picture quality is highly challenged by demanding professionals. PowerDVD 5 addresses the image quality with the new CLEV technology that automatically adjusts the scene's colors and contrasts to enhance the video image sharpness and detail. The same technology can be applied to CRT monitors, as well.


Interesting .... so you want to muck with the source so it looks good on an LCD. Wont look good on a TV then BTW.

Best option is not to change the source ... but change the viewing device.

Other than that, you'd have to know what CLEV is doing to mimic it. But you could try to match it using some color bars, your eyeballs, and some way to measure (like a color picker or a waveform monitor).

Anyway ... 4 basic things to change about color. 3 are the same as on any old TV set.

- Black level: which is called birghtness. This moves the luma component up and down the scale. VDub has filters that do this. Move it up, and black becomes grey and white gets too bright.

- White level: which is contrast. This stretches the luma scale up and down. Set the black point so black is dark, and stretch the white so you use the full scale and normal whites are not too bright. I like a little dark with room for flash highlights. Same vdub filters as black level.

- Saturation: which is saturation :) This increases/reduces the color component. I find it best to target the colors since mucking with all at once tends to make things too red. Neuron made a nice filter that lets you basically target colors.

- Gamma: not on a TV. Luma is a nonlinear function ... the 1/2 value (128) is not 1/2 bright as the max value (255). So the IIRC high range has fewer values than the low range. Changing this value basically changes the proportion of values available to the high and low (and mid) ranges. BugsBunny made a fancy curves that does this, and there is a built in that does this in basic. You can use this to bring out details in the dark area you could not see (at the expense of some other range).

- There is also Tint. Use this to make the people blue. Probably don't need this.

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Bottom line .... doing color correction requires you to see your results and determine what looks good. AKA, you will be correcting to a specific monitor, and it will probably not look good on another monitor type. DVDs are probably created to look ok on a normal crt TV. These kind of changes will also loose info. It is probably best to not do this to a high quality source, but to adjust your viewing device.

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At least that's what I sorta think about the topic.

:D

[dark.soft]

Hi trevlac, thank you for your help, but you have misunderstood some things. First of all, I use CLEV on a 19" crt monitor, wich is very good in reproducing colors, but I noticed that dvds are much better with CLEV on. So, I'd want to reproduce that beautiful effect(if you watch matrix reloaded with CLEV and without, and then tell me :) ) on the xvids that I am going to encode for use them on a pda, so I want to optimize them to look good on that screen, because I'll not watch them on pc or other devices (but I think that playing them on a normal pc it would be good).

P.S. I was searching for your spectacular plugin "colortools", but your web space is offline, can you tell me where to find it?

[trevlac]

P.S. I was searching for your spectacular plugin "colortools", but your web space is offline, can you tell me where to find it?

:Blush:

Hey!? If you can't find it, how do you know it's spectacular? Are you trying to 'butter me up'? :)

http://www.trevlac.us/colorCorrection/index.html Works for me. Maybe try without the www.

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Anyway, my quote was from the PowerDVD folks themselves. They market CLEV as fixin LCD TVs I guess.

I think the difference is still the picture production aspects of the display, and DVDs are made for CRT TVs. Your CRT is no doubt a PC crt, not a video monitor (like a TV). Some differences in my viewing experience are 1) the gamma is different. 2) TVs have higher saturation in bright colors. 3) TVs are not ment to be as bright.

You should be able to do the CLEV thing (assuming it does not change as the signal changes) by just making adjustments to a set of colorbars and gradations and doing comparisons.

I'd also do some tests on your PDA to make sure it looks good there before you did a bunch of encodes. Make sure you use the same type of environment (day light vs night vs indoor) that you are going to normally view under.

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Some of my personal experience on this sorta stuff ....
I have a relatively cheap LCD TV. As a PC monitor it does great. With video input, it's quite poor. Washed out ... etc. I can adjust my input devices or the monitor, but it is usually a pain. I have satellite TV. The composite out from the receiver is really off the scale in saturation and has a very wide contrast range. S-Video is much less. But it does look like my provider juices everything up to make the picture look better. Problem is that on a normal TV (which usually has too red of a picture) red is too high for the composite. I have a hauppague mediaMPV (newly aquired). It's a nifty little network device that lets you stream mpeg around the house. Problem is that it decodes/outputs the video way oversaturated for a normal TV. Maybe I should hook it up to my LCD ? :) My point is ... in my experience ... general consumer stuff is all over the place. Must drive the Pros (who care) crazy when they try to produce good stuff for the home market.

Cheers!

[E-Male]

CLEV, i think that was the feature that turned my b&w movie blue

[dark.soft]

Hey!? If you can't find it, how do you know it's spectacular? Are you trying to 'butter me up'?
I know it's spectacular because I have read doom9's guide on analog capture, and there are many shoots of your plugin in that guide.

I'll try some color combinations and tell you.

[zoinbergs]

Now I personally loved the CLEV-2 setting that PowerDVD game my movies too, and wanted to reproduce the results for my DivX burns..

so I started playing with some AviSynth filters.. and after dozens of minor changes, I have created the closest reproduction (IMO) of CLEV-2, by inserting this into my scripts...


Tweak(0,1.2,0,1.0)
ConvertToRGB()
Levels(0,.93,255,0,255).RGBAdjust(1.2,1.2,1.2,1.0)
ConvertBackToYUY2()


I consider these my AVERAGE settings, as it gives me a close enough reproduction for any and all movies, even though some movies are naturally encoded more darker/lighter than others. I consider it "close enough" for all of 'em.

Occasionally I'll do a test run of a few frames to adjust accordingly though..

If the movie encodes too bright, I'll move the levels gamma to .92, and if the movie encodes too dark, I'll use .94.

I never touch the tweak saturation though, nor the RGBAdjustments, as any more or less of those settings create changes that are too dramatic..

Anyways, you guys should try it! Compare the original PowerDVD movie to your DivX, and I'll bet you'll be impressed!

If anybody can help me out with some better settings, please let me know!

Good luck..