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4:4:4 Levels
I have a rookie question.
I digitized some footage for a client from a 4:4:4 23.98 HDCam SR master using an AJA KONA 3 card via duel-link into Final Cut Pro 7 using KONA’s 10-bit RGB DL Uncompressed codec.
I’ve noticed that although the video levels look okay when I preview the footage by sending it out of FCP, once again via Duel-link to a Videotek Harris waveform monitor, but FCP’s internal scopes show the levels as being somewhat out of whack. (Video comes up to about 92 IRE, blacks are at around 10 IRE)
I received a message from the client when they received the file that I sent them (the one straight out of the capture scratch folder), and they complained about the video levels as well, citing the same issues I saw on the FCP scopes. Due to time constraints, I had to come up with a solution fast, so I resorted to tweeking the footage with a Proc Amp filter in FCP, rendering and re-exporting.
I wasn’t completely satisfied with that solution though, so I was wondering if anyone could offer some general insight as to why the levels appear to be different, as well as any tips on settings or preferences that can be altered to accommodate this quirk with FCP.
Thank you.
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Dan Charrington
Supervisor, Non-Linear TechnologiesMIJO
635 Queen St E. Toronto, ON
416-964-7539MacPro 8-core Xeon 2.8GHz, 10gb Ram, AJA Kona 3 SD/HD
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3 Replies
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10b RGB codecs has two ways to map Black and Whites: “Full range” and “Video range” .
Make a short test capturing the same stuff both modes and see how they look on the waveform.
You can not pay attention to the FC scope dealing with this kind of stuff.
You better use the Color’s scope.
rafael -
Thanks for the response Rafael.
I wouldn’t dream of relying on the scopes in FCP. Not when I have hardware scopes to rely on.
I did the tests you suggested. The only way I could find to change the mapping option you suggested in FCP was to dive into the Capture Preset Editor on one of the codecs I’ve been using. (The 10-bit RGB AJA Kona3 one).
In the Advanced tab under the Quicktime Video Settings, there was an option to switch the “Range” from SMPTE (64-940) to FULL (0-1023)
I digitized some 4:4:4 footage under both settings, but the results were the same.
At this point, I’m merely fishing around for insight purely for my own curiosity. Down the line though, if I ever have to end up working with 4:4:4 footage again, it’d be nice to have a solution to the whole levels-being-altered thing besides simply fixing it with a simple filter, render and export if it turns out an exported file is the desired outcome.
Again, though… thanks for the insight.
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Dan Charrington
Supervisor, Non-Linear TechnologiesMIJO
635 Queen St E. Toronto, ON
416-964-7539MacPro 8-core Xeon 2.8GHz, 10gb Ram, AJA Kona 3 SD/HD
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[Dan Charrington] “Due to time constraints, I had to come up with a solution fast, so I resorted to tweeking the footage with a Proc Amp filter in FCP, rendering and re-exporting”
FC works only at 8b when in RGB.
Use Color set to Floating Point.
rafael
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