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View Full Version : gamma shift exporting from RedRocket & RocketCine X.



Michael Totten
11-15-2009, 11:07 AM
The shot in RocketCineX looks much more saturated with the black levels where I want them. Then I export using the preset "Quicktime H264 1920X1080) and the footage comes out milky, desaturated and looks brighter than before.

I'm assuming this is apple gamma shift. How can I fix it? Also, I'm trying to get the best results for vimeo.... I'm assuming transcoding directly to H.264 directly off of the R3D files via rocketCineX would yield the best results (can anyone verify this... are there specific settings that I should use).

thanks,
Michael

jimhare
11-15-2009, 01:20 PM
Snow Leopard seems to be the best way forward. All gamma corrections, other than getting your QT settings right in prefs, vary from user to user.

If you have ENABLE FINAL CUT STUDIO COLOR COMPATIBILITY selected, you've done about as much as you can.

Michael Totten
11-15-2009, 01:32 PM
Snow Leopard seems to be the best way forward. All gamma corrections, other than getting your QT settings right in prefs, vary from user to user.

If you have ENABLE FINAL CUT STUDIO COLOR COMPATIBILITY selected, you've done about as much as you can.

I'm running snow leopard. Where do I enable "final cut studio color compatibility" ?

thank you,
Michael

jimhare
11-15-2009, 03:41 PM
Really? From what I've heard you shouldn't be experiencing a gamma shift at all.

I think I remember reading that going directly to H264 is a problem. Try transcoding to ProRes and see if you don't get the shift.

Mike Prevette
11-16-2009, 01:32 PM
I'm running Snow leopard, and RocketcineX and am not experiencing any shift in Gamma or chroma. Rendering to both AVID DNXHD QT's and Prores QT's

Brandon Kraemer
11-16-2009, 01:37 PM
H.264 encoding is notorious for shifting values... Compressor (Apple) has a setting called preserve source color in it's H.264 encoder that prevents this shift. You need to turn this on, not the default. It could be that there isn't the necessary filtering with in the codec, as Redcine writes to it, to keep this shift from occurring.

I haven't seen any shift issues in Redcine (running snow leopard) but I am usually going to Uncompressed 10-bit or DPX.

Michael Totten
11-17-2009, 09:01 AM
H.264 encoding is notorious for shifting values... Compressor (Apple) has a setting called preserve source color in it's H.264 encoder that prevents this shift. You need to turn this on, not the default. It could be that there isn't the necessary filtering with in the codec, as Redcine writes to it, to keep this shift from occurring.

I haven't seen any shift issues in Redcine (running snow leopard) but I am usually going to Uncompressed 10-bit or DPX.

Yeah it seems to be isolated to H.264, I found the "preserve color" setting but I'm not sure that it actually applied to all H.264 settings (I had to create and name settings in Compressor, but how do I tell RocketCineX to use that specific one) ?
thanks so much.
michael

Colin Hubick
11-17-2009, 01:27 PM
Here is a quick solution to the gamma shift with H264.

SOLUTION: After rendering into a QuickTime/h.264 file, open it up in QuickTime and select “Show Movie Properties.” Highlight the video track then click on the “Visual Settings” tab. Towards the bottom left you should see “Transparency” with a drop-down box next to it. Select “Blend” from the menu then move the “Transparency Level” slider to 100%. Choose “Straight Alpha” from the same drop-down and close the properties window and finally “Save.”

Not ideal, but it works.

Michael Totten
11-17-2009, 06:02 PM
Here is a quick solution to the gamma shift with H264.

SOLUTION: After rendering into a QuickTime/h.264 file, open it up in QuickTime and select “Show Movie Properties.” Highlight the video track then click on the “Visual Settings” tab. Towards the bottom left you should see “Transparency” with a drop-down box next to it. Select “Blend” from the menu then move the “Transparency Level” slider to 100%. Choose “Straight Alpha” from the same drop-down and close the properties window and finally “Save.”

Not ideal, but it works.

Ok this sounds like a great little trick. thank you: )
Does this work in "quicktime x" ? I can't find "show movie properties".
thanks,
Michael

Mike Prevette
11-17-2009, 06:03 PM
Does not work in Quicktime X, you need to open it in quicktime 7 on snow leopard

Colin Hubick
11-17-2009, 06:15 PM
...needs to be Quicktime Pro to access the menu...

like I said, not ideal but it works, and you don't need to re-render.