So the blu-rays were encoded RGB Full, rather than RGB limited?
As I understand it, TVs use a video range from 16-235. It considers levels below 16 to be black, and information above 235 is white. A calibrated TV will never display anything below 16 as anything other than black. Most will also treat everything over 235 as white since it should not exist in video content.
PCs are different and use a range from 0-255. There is no data below 0 or above 255 with an 8-bit video signal as there are only 256 possible values. In short, this is much simpler to understand as the TV concepts of Blacker-than-Black and Whiter-than-White do not exist.
Therefore to make the conversion between RGB Full (“PC Mode”) and RGB Limited (“TV Mode”) all you need is the following levels adjustment in AVISynth
// PC to TV ; scales a [0,255] clip to [16,235]:
Levels(0, 1, 255, 16, 235, coring=false)
Not exactly 😃,the encoded materials use a video range of 16-235 for luma and 16-240 for chroma.
If the input is yuv limited range every tv before the yuv-rgb conversion does a levels expansion from 16-235 to 0-255 for luma and 16-240 to 0-255 for chroma,so the tv can display true white and true black.
From what i understand the blurays were encoded in non-standard yuv limited range,so instead of 16-235 we have for example 16-242.The good is that the highlights aren’t really clipped.