Originally Posted by shs1234
The “HDR to SDR conversion” and tone mapping in the 820, or any video processing algorithm, can’t make your display any brighter in terms of the brightest whites or highlights - that is a limitation of the display itself. What it can do is to make the image appear brighter by bringing up the mid-tones or parts of the image that are not the brightest whites or the deepest black. It is all the levels between black and white that comprise most of the image you see. How bright those areas are will determine how dark or bright the overall image appears. The goal of tone mapping is to make those areas look right on your particular display.
All displays use an algorithm to translate the numbers or bits associate with the brightness of any given pixel in the video stream to exactly how bright it will appear on the display. This is called the electro-optical transfer function (EOTF) and/or the gamma for the display.
As Kris Deering would say, the HDR to SDR conversion does not really convert HDR to SDR. The conversion on the 820 maintains the HDR color space, B.T. 2020 and bid depth, 10 or 12 bits, rather that converting to the real SDR’s Rec 709 and 8 bits. So, the image is really HDR in those respects. In the process however that video stream is converted from the HDR PQ gamma to the SDR 2.4 gamma function, and ideally does so in a way that tone maps the image intensity data to the abilities, e.g. available brightness, of the display. It is possible to customize this mapping to make the overall image appear brighter while at the same time keeping the brightest parts of the image from clipping. It works very well!
I hope this helps.
Thanks shs1234. I think you have said all I need to know at the moment:
"and ideally does so in a way that tone maps the image intensity data to the abilities, e.g. available brightness, of the display. It is possible to customize this mapping to make the overall image appear brighter while at the same time keeping the brightest parts of the image from clipping. It works very well!"
Clearly my LG player doesn't do this at the moment because it doesn't take account of the display being used.
I might just clear up a point about OLED's. They are not the brightest TV's on the market, most high range led/lcd UHD 4k TV's are brighter. The reason OLED's can give such a good picture is that they do perfect blacks.
I am not complaining about the tv's SD or HD brightness performance, nor am I complaining about HD Blu-rays. It is just UHD blu-rays with HDR and DV that come out too dark. I accept the OLED is capable of giving a brilliant picture with HLG 4k UHD metadata as I said in my original post - ie Planet Earth II. It's just that UHD discs with HDR and DV - presumably the 4,000 nit mastered ones that come out extremely dark and no adjustment cures this without raising the blacks to grey (brightness setting). Maybe I have got an outlier in OLED panels but the difference with the same film on Blu-ray and on UHD Blu-ray is clearly visible.
What shs1234 has said above confirms the two benefits that the 820 will give me: 1. None or reduced clipping of whites at the bright end and 2. the increase in brightness of everything else.
It would be interesting to see what effect you get on your projector systems by selecting OLED on the player (I understand this assumes a 1,000 nit capability - the led/lcd TV setting assumes a higher value).