QuickTime manipulating my gamma and clipping my superwhites

[Rich Rubasch]

Excellent request…oh, and good luck with that…

We’ll be rooting for you.

Rich Rubasch
Tilt Media

[Misha Aranyshev]

This is a major issue with QuickTime that causes surprisingly few complains. Does everybody knows a workaround I’m unaware of or does everyone simply gave up? Did fighting the dreaded luma clamping issue in the days of FCP 1.2.5 exhausted the community power so much?

[Annaël Beauchemin]

[Bj

[Danny Dodge]

I think most people assume this problem is their problem, and don’t realize it’s everybody’s problem. Now that we’ve brought light to the issue I think more people are going to griping. But, how do you get the QT guys to wake up to this fact. I’ve seen gamma issues going to and from other codecs as well. Try going from HDV to mp2, or going from DVC PRO HD to mp2. One goes dark and the other goes lighter. This really pisses me off when I shoot for optimal latitude, color correct for a particular look and then everything gets bottle-necked by Compressor or QuickTIme.

Good luck on this. I hope enough people gripe about the problem so that something gets done.
Danny

[Sean Oneil]

This may or may not be a related issue, but I had a serious problem recently. A colorist worked on a project here by correcting in FCP on a DVCProHD sequence. Later, I wanted to downconvert it, so I copied and pasted the clips on to an Uncompressed SD timeline (tried 8-bit and 10-bit).

The luma shifted drasticly. It didn’t matter if I set it to White or Superwhite, High-precision 10-bit, etc. There was absolutely nothing I could do to keep the same color and luma as it was on the HD sequence.

Sean

[Danny Dodge]

I experienced this too. Your best bet is to export the HD timeline as an uncompressed .mov file and then import it onto an SD timeline. The last time I did this was a while back. But, I believe it will at least minimize t the shifting. If your lucky enough to have a card that will down convert from HD to SD (Kona 2, etc) then you should have no shifting at all. The world of HD and SD take some true skills to navigation between the two. Hope it helps.
Danny

[Oliver Busch]

You should keep in mind that SD (ITU 601) and HD (ITU 709) have different colorspaces and gamma.
Apple Uncompressed codecs decide whether to use HD or SD color space from the horizontal resolution. Any size higher than 720 pixels (D1 size) is processed in HD colorspace.

My 2 (Euro)cents
Oliver

[Oliver Busch]

You could try the (IMHO) brilliant Sheer Video codecs. They allow for fine grained setting of color space and luma range (16-235/0-255). They also contain technology for RGB/YCrCb conversion (and vice versa) without color changes.
https://www.bitjazz.com/sheervideo/index.shtml

Just my 2 (Euro)cents
Oliver

[Sean Oneil]

[Oliver Busch] “You should keep in mind that SD (ITU 601) and HD (ITU 709) have different colorspaces and gamma.
Apple Uncompressed codecs decide whether to use HD or SD color space from the horizontal resolution. Any size higher than 720 pixels (D1 size) is processed in HD colorspace.”

Thanks. Yes, I figured this was the reason for it.

The problem is that although the footage was HD, the colorist corrected it while viewing an NTSC monitor as it was being downconverted in RT. So for Quicktime to automatically decide to change this for me was undesireable.

Sean