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Testing 4:2:2 and 4:4:4 footage


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#1 renfield sonia

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Posted 06 December 2010 - 12:35 PM

Hi, I'm testing two different capture formats so to be able to stablish a proper workflow using a viper filmstream camera.
I have two different recorders, an OB1 that records DPX files in 4:4:4 uncompressed RGB files, and a P2 recorder that records video files encoded in 4:2:2 AVCINTRA 100 codec.
The images recorder on the ob1 where recorded from viper filmstream mode and the P2 from the HD stream coming from the viper, the difference would be basically a colour render ability, and wouldn't affect the total latitude of the camera, in m opinion (the HD stream and filmstream curves are supposed to be the same one, just adapted to 422 or 444 data flow)
So I imported the P2 footage into final cut and some DPX pictures (saved as TIFF files) that I grabbed from the OB1 recorder
I exposed the grey card and the colour card using an astro waveform monito, and set the grey point to 50%.
The problem I find is that none of the files I get in final cut seem to be properly exposed, according to my grey point, all of them are around this point, but randomly (there's no constant deviation).
Anyone know about how final cut works with those files, and if final cut waveform monitor is reliable?
Any suggestions about how to read properly the DPX files values, as well as some video stream file?
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#2 Jordan Gzesh

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Posted 10 December 2010 - 12:45 PM

Things may have changed and I may not be able to offer total insight, but one piece of interesting information that I learned a little while back is that the waveform and vectorscopes built into color and final cut are actually sampling a single interlaced field of information from the source. Take this into consideration when questioning the reliability of the scopes.
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#3 John Sprung

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Posted 10 December 2010 - 02:10 PM

I don't see how that would impair the results in a detectable way.



-- J.S.
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