New in 2018: HDR to SDR conversion
HDfury X4 is now capable of converting 1080p HDR to 1080p SDR for perfect streaming while gaming in 4K HDR, for ambient light solution or for capture and display needs.
The difficulty with this HDR to SDR conversion actually does not lie in the algorithmic mapping of HDR PQ signal into the SDR domain but the fact that the result video even when converted with just PQ conversion does not look the same on TV.
Its clear that when a HDR tv goes into HDR mode, it activates processing that is not uniform across different TVs. the image appears somewhat different between HDR TVs based on our experiments.
Therefore, said from another point of view, what you see on HDR TV – when converted back to SDR – does not appear similar on different 1080p screens because the HDR image already was different.
Also, different HDR sources are mastered for different target nits. Some for 1100 / 1400 or 4000 or 10000 nits. Regular SDR is 300nits. So converting and scaling from a moving target into 300nits is another issue. Sometimes image is darker and sometimes lighter.
All these taken into account the product needs a robust color processing in addition to PQ conversion. We have done just that and thats why the delay to do it. Here is the first iteration of all the color algos + PQ conversion done and to us they look good already.
All images are from PS4 4k60 422 12b 600MHz HDR. We are looking at the menus when pausing a game to keep the system in HDR.
The first image is on LG HDR TV. its the reference:
The second image is now a Vertex downscaled to 1080p60 444 12 bit HDR shown without any processing on a regular TV. This is how all TVs will show a HDR image. You see its all washed-out and suboptimal.
No amount of TV brightness/contrast/tone/etc control will bring this image any better. HDR on a SDR TV just looks bad because it looses all nits between 300 and the target..(1400/10000)
This last image is the same 1080p signal but now processed through our new algos on hdfury X4: