[Colin Tse]

Very lovely. Thanks Rafael.

[Colin Tse]

Thank you Rafael, you’ve done so much that I really appreciate and also real sorry to keep troubling you.

I’ve done the same and yes I can find the thin edge that may be the trouble source. The underwhite and overblack are the poor color correction from the offline editor which can be easily fixed. Our concentration is how to eliminate the illegal black (underblack).

I tried to replicate the same as you suggested but have some troubles:

1. I cannot find an option in Compressor to check broadcast safe on.

2. Applied all filters as suggested (even to a higher extend) can eliminate some underblack, but majority of them still persist. (As snapshot)

I don’t know if there is any wrong setting incorporated in my FCP machine that has different outcome from your test. Will go back and check again.

Also I will try to ask how the animation house create the file so to determine how these troublesome black thin lines are generated.

Thanks

Colin

[Colin Tse]

Thanks Rafael I learn so much from you!

The original footage was created from Flash by an animation house , so difficult to go back and change the color. (Not sure what gadget they used by don’t think its AE). Then converted to “Animation” mov wrapped for FCP edit.

1 frame sample file has been created as instructed and sent to you through email.

Very much appreciate for your help!!

Colin

[Colin Tse]

Sorry miss-press the button before I say thank you. By all means I don’t just look for a solution but also want to unveil the mysterious cause to enrich myself.

Much appreciated.

https://reels.creativecow.net/film/sample-for-underblack-video

[Colin Tse]

Thank you Rafael and frankly I learn so much from you.

I have my sequence set as ProRes422 HQ, render in high precision YUV, have cropped 1% of all edges, dropped in “RGB Limit” and “Broadcast Safe”, and under black still persist.

With curiosity I tried to crop further on the image and found that the under black have gone away when all black portion are cropped.

Further study I tried scaling up the picture and discovered that the underblack gradually raise up back to legal when I scale it heavily up say 300%. Sorry for my dumb would this because I blow the video signal up thus reducing the noise in the black?

I try to upload a sample of 1 sec and hope this can help the analysis.

[Colin Tse]

Very much appreciate for your help Rafael. I starts to suspect if the video itself has some strange color coding.

The picture originally looking like this:

and the RGB parade like this (1):

When I switch the seq codec to animation, the RGB parade looks like this (2):

The strange thing is, if I have the seq codec as ProRes422 (HQ), the parade looks like (1). However if change any parameter in the scope display (e.g. from parade to waveform back to parade, or change the current frame to previous then back to current, or scope display to “All Lines” or other), the parade looks just as good as (2)! But once I move to another frame, the parade back to the bad one (1).

Any change in scope display makes the parade look good and any move on timeline makes it look bad.

I guess I may have to go back to original animator for primary color grading as suggested, but curious why I couldn’t eliminate the underblack by all means within FCP. The best I can do is to raise up the black level, making everything greyish.

Thanks very much for your kind assistance.

[Colin Tse]

I did the trial and it looks the same. However I discovered that the color is perfectly legal in RGB space, however bleach out in YUV space. May be this is the reason why RGB limit not works since it clips all illegal color only according to RGB color space.

The trouble is I need to make the video also legal within YUV space for broadcast.

[Colin Tse]

Thanks Rafael and I’ll try your suggestion and see if it gives any better result.

However I’ve tried three FCP stations with same configuration and hardware spec, all have the same result. Could this possibly be any config or hardware related issue?

[Colin Tse]

Very much appreciate all the good thoughts and input.

I couldn’t find a good way to eliminate the sub black so guess just stick into “Animation” codec by now. Will do more experiment and research to see if better achievement can be made.

Thanks

[Colin Tse]

The sub black also on output when checking on an external tektronix WFM.