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Join Date: Apr 2002
Location: Denver, Colorado
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Here's a little primer on HDR10+; the intent of the "plus" format is scene by scene or even frame by frame dynamic metadata. Whenever you convert from a larger color volume (BT2100) to (Rec.709), there will be code values in the center that are shared but as you approach the boundaries of the larger space, the smaller space no longer contains any corresponding data values. In other words, for an average scene no difference, but for a very bright or very dark or very colorful scene the BT2100 code values fall outside the range of Rec.709. There are no implications for HDR but the SDR layer will play much better. So the intent of HDR10+ is better playback of the SDR layer with no advantage for an HDR device that supports the full range of the recording.
Authoring HDR10+ is exactly the same for the HDR layer as regular HDR10 except that it is followed by a computer analysis. After the analysis, a panel is opened that has various curves with handles you can adjust to tweak the image so that each scene looks its best, but the image being tweaked is for the SDR or the <4000Nit display. For Dolby Vision it is exactly that; any level below 4000 nit, 3000, 2000, 1000, 200 etc. For HDR10+ it's really only the SDR layer being adjusted at all. Once you've made these adjustments, by scene or by frame, you save the results in a *.json sidecar file. The file is attached to the HDR video file inside a container, like *.MKV. when the file is loaded by the playback device, the metadata is also loaded which points to different tone mapping for each frame or clip for the entire length of the video.
I don't think YouTube yet supports HDR10+. When I encoded an HDR10+ file around a year ago when it was announced, it would not play on YouTube then. If it would, the problem it solves is the problem we have with the YouTube SDR conversion that looks flat and weak compared regular, non-HDR content, a problem again caused by the smaller color volume of SDR space.
When I saw the Galaxy HDR10+ videos, the SDR looked great(!!) which gave hope that HDR10+ was working, but then it was the HDR stream itself that would not play, exactly as happened to me a year ago when I tried it. Unfortunately, I've never seen HDR10+ high dynamic range video because I've not had a play with a compatible Samsung device, however the HDR layer did play fine on my Samsung, and I don't know when you would see the benefit of the enhanced SDR layer on a device that is already compatible with the HDR layer. My Samsung which is not HDR10+ compatible, plays the HDR10+ fine because it just ignores the dynamic metadata which it doesn't need anyway to play the HDR stream. Presumably there could be some tablets or phones that don't have the full brightness >1000 nit of HDR, could use the HDR10+ scene by scene tone mappings, and would be the beneficiaries of HDR10+.
HDR Colorist and Conversions
INTO THE CAVE OF WONDERS
Directed by MANUEL BENITO DE VALLE Produced by PEDRO PABLO FIGUEROA
Cast MANUEL ANGEL REINA, CLAUDIA GARROTE
LOVETHEFRAME STORIES, SOUNDTRACKS AND FILMS