16-235 > 1-255

I can't believe this has come up again, but here we are ladies and gentlemen. One of our television graphic systems is delivering work at rec709 colourspace (16-235) and we need to export a QuickTime at basically sRGB or 0-255. I remember manually creating a gain/brightness profile or Proc-Amp preset or some such on the old machines to do this.

Please tell me the conversion is a clicky now like it is on the Avids.

Oh please, oh please, oh please.

Koz

FCP 7.0.3 current as of about six months ago.
2.8 GHz Quad Core Xenon
OS-X 10.6.7

RGB files? Sequence settings, map RGB white point to superwhites. I'm not sure if it does black points, though. And yea, switch source gamma to 2.2



www.strypesinpost.com

I don't need to change the sequence. Just the clip. Play the movie and everything is just grand until you hit that one clip, then it's dull and pasty (wrong colorspace) and then it returns to "normal" after the clip is done.

Fix the clip. We know precisely what's wrong with it.

The other thing we may need to do is completely edit and produce a movie in req709, say for a BluRay, and then deliver a Quicktime in sRGB. (the other colors).

I understand this doesn't bother anybody other than people who's two business branches crank along in very different color standards. There may be four of us out there.

Koz

Koz: BT.709's 16-235 and 16-240 ranges are RGB 0-255 ranges. For example, white with Y'=235; CB=CR=128 becomes white with R'=G'=B'=255, black with Y'=16; CB=CR=128 becomes black with R'=G'=B'=0, red with Y'=62; CB=102; CR=240 becomes red with R'=255; G'=0; B'=0, etc., according to the BT.709 equations. The sRGB primaries are exactly the same as the BT.709 primaries. And the quasi-gamma for sRGB is not very different from ordinary gamma 2.2. sRGB isn't inherently more colorful than BT.709.

The dull and pasty symptom you describe is not from the BT.709 ranges being too short but from their not being fully used. Bum software converting color spaces often causes this. If the conversion made a simple mistake, which didn't involve clipping, then you might be able to undo it. FCP has a fair set of tools in Effects>Video Filters>Image Control, including your old friend "proc amp".

Dennis Couzin
Berlin, Germany

Koz-

I wouldn't have a clue about color space conversions-- sRGB?? Yuck. Consumer grade colorspace, isn't it?-- but if you do, you could easily set up and save a Favorite using Option-F to store your ProcAmp, CC3Y, or that special colorspace conversion filter you've always been meaning to get-- now who was that vendor? And then just have it ready to drop onto trouble clips.

Your first four FCP favorites in each category -- transitions, V & A filters, motion path fx, -- are hard wired to keys for instant application. For instance, Control-Shift 2 allows you to apply a saved video filter to a selected clip. For subsequent saved favorites you get into Control-Shift-Letter combinations. You'll remember these if you use them a lot.

Good luck.

- Loren

Today's FCP 7 keytip:
Temporarily mix down audio tracks with Command-Option - R !

Your Final Cut Studio KeyGuide? Power Pack
with FCP7 KeyGuide --
now available at KeyGuide Central.
www.neotrondesign.com

That sequence setting I mentioned tells FCP how to map RGB sources (eg. Jpgs, animation, etc). It doesn't affect the rest of your video which is in Y'CbCr.



www.strypesinpost.com

It's worth giving QT Edit a try as it can modify a clip's color space metadata:
[www.digitalrebellion.com]

Just open the QuickTime movie, select the Video track and go to the Attributes tab. You may need to click the + button to add a Color Space atom. You'll be able to see the results of any of the selections you make in the preview window.

My software:
Pro Maintenance Tools - Tools to keep Final Cut Studio, Final Cut Pro X, Avid Media Composer and Adobe Premiere Pro running smoothly and fix problems when they arise
Pro Media Tools - Edit QuickTime chapters and metadata, detect gamma shifts, edit markers, watch renders and more
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