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Video Levels - M100 to Compressor

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Tom
Video Levels - M100 to Compressor
by
on Apr 11, 2005 at 11:14:54 pm

Sorry for the (probably) redundant post, but I've spent an hour looking through the Cow Archives and spent several nights compressing a 1.5 hour wedding (overnight and then some on a dual 867 G4...), but am consistently coming up with crappy levels after the compression.

I know that this topic has been addressed in some length here previously, but I am hoping, after my week of failed attempts, that someone can provide me with some starter "settings" that they use within Compressor's "Filters" tab to make their compressed blacks & whites similar to (or at least closer) the original Media 100 output.

If anyone has their set of preferred settings for the "filters" tab in Compressor, or at least a head start, it would be GREATLY appreciated and would save me possibly many more nights, and probably a few hairs.

TIA,

Tom


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Floh
Re: Video Levels - M100 to Compressor
by
on Apr 12, 2005 at 6:50:03 am

I know that this does not really help you with Compressor, but BitVice from Innobits does compensate the levels to match the original Media 100 i or HD levels. They have an option called "StudioRGB" that does exactly that.


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Daniel_l
Re: Video Levels - M100 to Compressor
on Apr 12, 2005 at 1:03:48 pm

Rule of thumb - If you're going to a web/computer device delivery codec then the simpliest way is to simply increase contrast to get blacks black and whites white and then to stop the whites becoming blown-out, drop the brightness slightly. You're basically expanding from video (601) 16-235 to RGB 0-255.
Of you're going to a broadcast codec/standard you shouldn't need to do anything unless you are targeting only computer display device types.


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Tom
Re: Video Levels - M100 to Compressor
by
on Apr 12, 2005 at 1:27:57 pm

Thanks for the advice - certainly I will eventually take a look at Bitvice, and the general Brightness/Contrast tweaks are what I've been trying...

BUT - can't help but thinking that the "Black/White Restore" could help, and still hoping for a few actual setting/numbers that people are using....I know some of you guys are using this and have to be having the same problems...

Is anyone restoring/tweaking their Blacks & Whites within Compressor?

Tom


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Daniel_l
Re: Video Levels - M100 to Compressor
on Apr 12, 2005 at 1:40:03 pm

Restoring can work well but generally you'll find that the values set will not work across a whole clip.
Usually actual values are dependant on the footage (format, PAL or NTSC, lighting, camera model etc etc) but you'll find that application like cleaner & procoder have a 601 correction preset. It really always is a question of trial and error.
Experienced colour correctors never use presets or set values, only doing it by eye.
As i said previously you are only expanding from 16-235 to 0-255 you should be able to figure out some % change from those values.


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Tom
Re: Video Levels - M100 to Compressor
by
on Apr 12, 2005 at 3:00:04 pm

"As i said previously you are only expanding from 16-235 to 0-255 you should be able to figure out some % change from those values."


Well, Brightness/Contrast are each on a scale of -100 to +100. I don't see how percentages derived from RGB 16-235 to 0-255 will correlate to individual B/C settings...? You mentioned lowering brightness and increasing contrast...but how are you "automatically" calculating their percentage equivalents to the 16-235 to 0-255 conversion? It seems like apples and oranges to me...

Tom


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Daniel_l
Re: Video Levels - M100 to Compressor
on Apr 12, 2005 at 3:14:57 pm

Nothing automatic - I use my eyes. If there was a magic formula, or a library of perfect presets, I'd be out of a job.

Bottom line is make sure black is black and white is white, but not too white!

You might find some more help here:

http://www.poynton.com/notes/brightness_and_contrast/index.html
http://www.poynton.com/notes/colour_and_gamma/GammaFAQ.html

DL


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Tom
Re: Video Levels - M100 to Compressor
by
on Apr 12, 2005 at 3:53:53 pm

Sorry, I just can't resist.

This is like trying to drag an answer out of the engineer at the facility I work at. Obviously I'll be "using my eyes" to determine if the settings are helping or hurting the footage, and certainly I know that there are no magic presets.

I do know that when you (and others who use M100, Compressor and care about their video levels) sit down and begin to tweak their B/C settings in the "filters" tab, you/they START with a number in brightness and a number in contrast. It it -50? +10? +14? I'm sure there are numbers that ONE STARTS WITH...and then tweaks from there. Naturally I realize that there is tweaking and judgement involved.

That is all I'm looking for...a starting point. I've read the manuals. I've scoured the archives. I've done test after test. My cpu has been "compresssing" for days now. Simply looking for a starting point.

I appreciate the thorough and lengthy articles that you've posted regarding B/C and gamma theory, and some day I will take the time to read them...but under these deadlines I am simply looking for that starting point from which to tweak.

If you are unable to provide those due to secrecy or the fact that "all footage is different and I never ever start with the same numbers," then a million thanks for your efforts so far...I'm sure the articles will come in handy.

Sorry for any snippiness, just been working on this for a long time, seeing the light at the end of the tunnel, but the tunnel floor is covered in quicksand.

Tom



PS - BTW...Just as when one imports M100 footage to AE and adjusts input levels to 16/235 and renders with output levels set to 16/235, and that is done EVERY TIME REGARDLESS OF FOOTAGE, I find it hard to believe that once one finds satisfactory B/C adjustments in Compressor, that there is no reason they can't be used every time, with judicious tweaking as one sees fit, but those settings, should, in theory, be able to be locked in stone. Its just a mathematical formula, no?...regardless of the "magic preset" being a myth or not.


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Daniel_l
Re: Video Levels - M100 to Compressor
on Apr 12, 2005 at 4:03:52 pm

Tom,

Brightness -3
Contrast +12

The above is a 'starting' point for PAL. Luckily I've had very little to do with NTSC.

DL
p.s. I still dont know what your source format is and what you are delivering to....


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Tom
Re: Video Levels - M100 to Compressor
by
on Apr 12, 2005 at 4:41:28 pm

Awesome...thank you very much.

I am working with NTSC - footage poorly shot w/ a 3ccd DV cam, and going to MPEG2 for DVD.

Will this affect what those starter settings, or what I am trying to do in general?

Thanks again,

Tom


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