litote wrote:From two replies in that other forum I am assured that by just setting Data Levels to Auto or Video in DELIVER-Render Settings there should be no problems, in their experience at least. They didn’t mention a particular broadcaster’s standard or very clearly explain why there is both an Auto and Video option and if there is any difference between them, or why you should leave it at default (Auto).
This is the only specific instruction that was posted on how to set a legal luma level in Davinci, so the other posts were of little help. If I must manually set the legal values for different broadcaster standards for luma levels, it was not answered as to how to actually set them in Resolve.
Further complicating the issue is that I am aware there is another way of setting limits, via a LUT.
If you concerned only about luma then there is really 1 standard (at leats for modern/current digital world). Luma must be in legal levels (64-940 for 10bit, 16-235 for 8bit) and that's about it. Broadcasters may have different threshold how much it can go below/above it. Most use EBU R103 standard which allows for luma to go few % outside perfect levels. Current spec is here:
https://tech.ebu.ch/docs/r/r103.pdfAs you see luma can be within 20-984, so there is a fair amount of margin.
There should be also more than 1% of the whole frame with bad pixels to be treated as invalid signal. All those thresholds are there to cover lossy compression overshoots (they do happen even for intermediate codecs). If you encode something to ProRes or DNxHR and look at high contrast areas you will find blacks going <64.
As I said- you really making it more complicated then it's. Don't every tick "preserve super blacks/whites" and your files will never fall outside those "perfect" levels and fail for luma errors on QC. It's not so "easy" with some other NLEs which operate in YUV. Then you can easier go out of safe.
If you read this document carefully then you will find this:
"When television signals are
manipulated in YUV form, it is possible to produce "illegal" combinations that, when de-matrixed, would produce R, G or B signals outside the range 0% to 100%."
Resolve operates in RGB and then data is converted to YUV on export, so by staying away from super blacks/white setting you should really never fall into problems (if later QC is done properly). You are protected by pure math
If you don't believe use do what Howard suggested.