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Resolve Clipping Input Video
Hi
I have just set up my system and I’m not sure if I have something set up wrong but it appears that Resolve is clipping video to legal before I add a a grade to it. I have a sequence from Avid that has many shots peaking above 100% on the RGB parade on my external scope. Normally I grade in Avid and pull any of these shots down into legal to avoid clipping and losing detail once the signal hits the legaliser.
In Resolve the footage comes in without any level/gamma shift problems but the highlights have been clipped to 100%. When I reduce the gain the hard clipped signal comes down and peaks below 100% and no extra detail is revealed which suggests to me that the signal is clipped before the grade is applied and not just on output.
I have tried switching the Video Monitoring to full RGB but this just scales the clipped signal to full RGB and does not bring back the original detail. I have also tried the soft clip LUT at 64-940 and this does not bring it back either – the output is then the same as ‘Scaled Legal Video.’
I am using a ‘1:1 1080i50 mxf’ file and the signal has detail above 100% when I import the file back into Avid. I have also tried ‘Uncompressed 8 Bit’ and ‘ProRes’ – same result.
Perhaps Resolve does all its processing in RGB colour space and once an Rec 709(64-940) signal is scaled to RGB (0-1023) for processing the headroom (signal above 940 or below 64) is clipped. Or perhaps I’m just missing something in the setup. Any advice would be much appreciated.
Thanks,
Brendan -
10 Replies
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Try the tab marked unscaled full range data.
Darin Wooldridge
Freelance Colorist / Technical Strategist
818-653-3918-cell
dwooldridge@mac.com -
Yes tried that – it just seems to scale the clipped levels from 64-940 to 0-123.
I am testing now using SMPTE colour bars. When I look at the Avid output everything is fine on the scopes and I have the bar of ‘super black’ near the bottom right of screen. When I take the test signal into resolve everything lines up however the ‘super black’ bar has been clipped or legalised to black.
Lifting the blacks does not reveal the ‘super black’ bar – it has been clipped off, meaning that any detail that is below 64 or above 940 (super blacks or super whites) is clipped and lost before grading starts.
Choosing ‘Unscaled Full Range’ pushes the white to 1023 and black to 0 meaning any super white or super black is still lost and colour bars now sit at the incorrect level.
Is it possible to import SMTE colour bars and retain the bar of ‘super black’? If this can’t be done it would prove that Resolve is clipping footage (losing detail) before grading even begins.
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Hi Guys
I’m getting the same thing happening with DVC Pro hd material, clipped whites, also tried changing the mentioned settings but no gain in detail above 100% of incoming video signal
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Looks like its a codec thing. I’ve been trying to get Avid mxf files to work but they are always clipped. I have now managed to get the colour bars from Avid to Resolve using ProRes422 and it all works perfectly – ‘super blacks’ included – just need to use ‘Unscaled Full Range’ in Resolve and export from Avid as rec709 with no gamma correction. I was very happy to get this working but would love to get the mxf workflow happening.
Another problem I have is with Uncompressed 8 or 10bit quicktime files from avid – there is some very strange hue/gamma shift happening when that gets into Resolve – I’ll test some more – still not sure if its an Avid or Resolve issue. I’m also interested in the DNxHD workflow. I might try to get the update this week.
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Very strange. I stick with dpx frames for grading, have had no issues.
If you load the same file into fcp and look at the scopes do you see all this lost info?
Looks like I need to do some testing. Are you setting the scope at 0_1023 or 64_940?Can send me a few frames of the example in a qt to play with?
Darin Wooldridge
dwooldridge@mac.com -
I just loaded the DVCpro hd project in Final cut and the scopes shows over 100% video signal in very bright images, then I sent to color and it confirms high levels, in color you can retrieve that extra 7% or so of high level
final cut scope
in Color scope
in Resolve scope I brought the levels down about 5% to show the hard clip that occurs at 100%
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Are you set in output monitoring to legal levels and not full range?
legal levels will clip everything at 64_940 as it should. go to full range and you should see everything you have in final cut.Darin
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Thanks for the accurate description of the problem.
A fix for this issue will be available soon.
It has to do with full range vs video range of the source clip for YUV formats (e.g. ProRes422, MXF DNxHD, etc.). DPX, ProRes4444, etc. should not show this issue.
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I am having this very issue. I Media Managed my sequence to Prores 4444 and all the above 100% info is evident on scopes from FCP. But then in Resolve it seems to be hard clipped at the input stage. The “unscaled full data range” in the video monitoring section stretches the signal out making it all look wrong (crushed and bright). Did anyone have a fix ti this? Version 8.2
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Right, I just transcoded to Prores 422 and now when I reduce the master gain, the clipped info “comes back” whereas before the flat line white would just move down on the scope. Tis all a bit weird but I can work like that I guess. It seems that when you select “normally scaled video” the output is clipped to 0% and 100% in resolve – NOT GOOD.
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