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Kona LH and PhotoJPEG
I’ve been struggling with an issue involving gamma shifts and PhotoJPEG codec. I’ve edited a 90 minute doc with this codec. The project has about 50% color correction applied with 3 Way and Color Finesse. The problem is when I try to do a dissolve from material with no effects to shots with rendered effects. I get a gamma shift on the dissolve in point. Not on every dissolve, though. Some tranitions work with no shift. In others, the gamma or black levels shift. Color seems fine and I don’t notice a color shift. I’ve tried using both RGB color processing in the sequence setting and YUV. What effects processing should I use for PhotoJPEG captured material. Isn’t PhotoJPEG an RGB codec? (like JPEG)
Also, I notice another related probelm. When I stop the playback, the gamma shifts. When I hit play it shifts back. It’s all frustrating and I’m not planning on using photoJPEG in the future for online.
But I’m not sure how to fix the problems. Should I just recompress the whole doc into another codec? I think it may be related to RGB vs YUV in the Kona LH, but maybe it’s a setting in FCPro 5.1.1.
Dave Beaty
Dreamtime Entertainment
3613 Del Prado Blvd.
Suite 202
Cape Coral FL 33904
239-549-4081
800-446-7575
da**@********************nt.com
http://www.dreamtimeentertainment.com -
2 Replies
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Dave,
Don’t know if this helps, but here’s what I’ve observed. We use “Off-line RT: Photojpeg” all the time for our off-line cuts. We make DVD’s for distribution. Just about every single transition that involves an effect (green screen in our case) experiences a level shift approx 1 second before the transition. Since this is for off-line review and approval only, so we’ve learned to ignore it. However, it’s there ALL the time.
In your case, it sounds like you’re using PhotoJPEG, but at full resolution. I would suggest trying a different codec.
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PhotoJPEG at 75% supposedly works as a YUV 4:2:2 codec. I’ve had the same gamma troubles however…as far as I can tell it’s an issue with timeline playback. Worth noting:
1. if you turn off the display of overlays in your canvas, the stop/start issue should disappear (i.e. you should have the same gamma when playing as when playhead is stopped.
2. if you export your timleline to quicktime — at least, if you export to quicktime self-contained — your gamma issues will be gone from the exported file (though you may need to clear render files before you do this). then you can reload this file and play out to tape. It’s not a very professional solution as we expect to be able to play from the timeline but I think it’s just that Apple hasn’t bothered to make this codec work reliably as an editing codec so most people are just using it for archiving, or if onlining then they do a work around like I’ve described.
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