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10bit conversion to PHOTO-JPEG = LUMA SHIFT?!
I’m having problems converting blackmagic 10bit files into PhotoJpeg 100% files using quicktime.
Check this out:
When I capture a 10-bit blackmagic file the luma is perfect, but when I …
… convert to photo-jpeg 100% using quicktime, the image is darker
… convert to photo-jpeg 100% using cleaner, the image is darker
… convert to motion jpeg 100% using quicktime, the image is daker
… convert to photo-jpeg 100% using final cut pro (quicktime conversion, not off a sequence just a straight clip conversion), the image is PERFECT! SAME LUMA!
… if I CAPTURE the clip using the photo-jpeg 100% codec the image is BRIGHTER!Ideally, I’d like to be able to do these conversions in cleaner or quicktime, but it looks like I’m going to have to do all of them from within Final Cut. What’s up with this disparity? Doesn’t final cut use quicktime to convert its movies? Why would they produce different results?
I’m on a G5 with blackmagic SD extreme card Final Cut Pro 5. Latest BM drivers. Latest FCP update.
Thanks,
Sam -
5 Replies
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At 100%, PhotoJPEG is RGB. Your video is YCbCr. Quicktime has “problems” with gamma shifts when converting between RGB and YCbCr. FCP, for the most part is pretty good, hence the differences. My advice – use PhotoJPEG75% which is YCbCr.
Graeme
– http://www.nattress.com – Film Effects and Standards Conversion for FCP
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in addition to graeme’s great reply:
the application MPEGSTREAMCLIP is a freebie but its MPeg4, H264 and other conversions look awesome!
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Thanks Graeme, but a quicktime photo-jpeg 75% conversion still gives a noticable luma shift. Also, the compression that comes with 75% is not acceptable for what we’re going for. On a TV it looks much better, but since we’ve got the space for Photo-Jpeg at 100%, might as well go with it.
I think we’re just going to do all of our conversions within Final Cut. Batch export is no big deal, it just ties up our final cut station for longer than we’d like.
Sam
p.s. Your FCP plugins are great. We use them all the time over here!
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What issues are you seeing with 75%? I’ve never seen it create compression artifacts at that level, even under extreme colour correction.
Graeme
– http://www.nattress.com – Film Effects and Standards Conversion for FCP
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The compression is only slightly noticable, but it is definitely there. You can see slight color smear in the intense reds and some slightly jagged edges on high contrast images. Like I said before, none of this is noticable on a TV, but it is noticable in Quicktime.
Either way it doesn’t matter, I’m still getting a luma shift when I go to 75% in QuickTime. So, it still looks like I’m going to do my conversions in FCP.
Thanks for the help.
Sam
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