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FCP broadcast safe not working.
First I have a ProRes 422 (HQ) mov in FCP7. I tried to apply color limit and broadcast safe filters to clip out illegal color for broadcast, however the super black on RGB parade cannot be clipped.
Next I change the sequence setting to DNxHD, apply the same filters and this time the illegal luma are nicely eliminated as seen in the scope. But once I render the sequence, or export as DNxHD mov, the visual turned back to original like without filter, and even the luma changed so obvious that I can see the difference by eyes.
I tried a lot of different codecs and all of them are either not able to remove the underblack, or not showing the same result after render. Eventually, the only codec that can reserve most of the visual quality and can clip out the underblack after export is “Animation”.
Can any one help to explain why? Perhaps a bug for FCP?
Thanks
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28 Replies
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Try with the “Levels” or the “RGB Limit” filters after the Broadcast Safe.
rafael -
Thank you Rafael, however it makes no difference by swapping the order of filters.
I tend not to use levels since it legalizes by washing out the video.
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Broadcast safe has never been reliable post render in any codec. By far the best broadcast safe filter is to export a QuickTime movie using current settings. Drop that into a new sequence- send to Color and click broadcast safe on in setup>preferences. Render and send back to FCP. Voila.
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Thanks Michael. The trickiest thing is that I did the same send to color with broadcast safe on, but the underblack still persist (scopes both inside FCP and external tektronix).
Could this have anything to do with my AJA Kona 3 card?
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Were their sub blacks in the luma waveform or just the parades? You can changes the broadcast safe parameters in Color and setup the black level.
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For me sounds strange.
The default value for Color Broadcast safe is 0 IRE.
In Color is easy to check the sub-blacks clipping checking ON and OFF the Broadcast Safe window.
rafael -
Not something I particularly worry about since I always correct my levels and only ever use the broadcast safe filter to catch any odd peaks that I might have missed, but I’ve just looked at the broadcast safe here and it does indeed allow sub-blacks in the RBG. The composite waveform is properly clipped though, so I guess the filter only legalises luminance and not gamut…
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[Andrew Rendell] “The composite waveform is properly clipped though, so I guess the filter only legalises luminance and not gamut…”
Yes legalize Luma, BUT..one of the problems with this filter is that do not really control the Chroma amplitude.
When it says “Custom Saturation Limiting”, what is really limiting is the full composite signal: Luma + Chroma. This is why the last slider is call Reduce Luma/Chroma. You can pull one or the other to keep the Composite signal below the limit.
The RGB Limiting only works in the highlight, do not clip under-blacks.
This is filter comes from the time of the SD NTSC and PAL, so was not intended to legalize things that were not a problem at that time (under-blacks and RGB gamut.HOWEVERy, the stand alone “RGB Limit” filter (Color Correction filters folder, no the one inside the Broadcast Safe filter) WORKS PROPERLY controlling the RGB levels, clipping RGB at the needed levels.
rafael -
So mysterious that I tried all methods and couldn’t simply clip out the underblack even with the use of Color, RGB Limit (the standalone filter). The only way I can do is to set the codec as “Animation”, or push up the black level in Color, however also crash out the black detail making the black as “greyish”.
Also curious about the incorrect luma/chroma of render for DNxHD. Is it because of the difference in color space for DNxHD and others say ProRes?
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