mark watson, netflix
kyokuske
nigel meggit, bbc
simon fraser, apple
paul kerr, netflix
pierre lemieux, movielabs
chris lilley, w3c
frederick hubenette, google
chris cameron, google
bill hofman, dolby
heif and jpeg xr handle hdr and wcg
canvas linear pixel math
tone mapping, hdr mapped to smaller space
rendering intent
using canvas rather than css to get finer control (!)
"brightest graphics white" not 10,000nit flare
http://www.color.org/chardata/rgb/scrgb.xalter
<smfr> https://www.w3.org/TR/ttml2/#hdr-compositing
raise issue on ttml2 compositing a) 2.4 gamma not real EOTF b) 80 nits not desirable value, too low
Can we fix IEC 61966-2-1:1999 for 80nits?
tv grading uses 100nits in dark room. so brighter in a mid lit room
how to get a good signal, then how to display that signal
secret sauce for the second part from tv manufacturers
tvs in hdr mode with a shader to boost up sdr content
<hubbe> https://docs.google.com/document/d/1A__vvTDKXt4qcuCcSN-vLzcQKuchnYmu8TFMDseIZJE/edit?usp=sharing
scrgb with 100 nits = 1.0
viewing environment modification not a linear shift - black area lift as well
css as the metadata
separate authorial from end-user decisions
three problems - compositing, viewing environment compensation, and tone mapping to display capabilities
compositing needs to know the level at which a paper white was graded. may be 100 for broadcast or may be like 300 for youtube hdr content
variable luminance gain like in ttml2
needs knowledge of the HDR is is compositing onto
uhd bluray grappling with the sdr hdr compositing for UI elements, now
HLG has a recommended way to composite SDR; 2020 and 2100 with PQ do not
<nigel> https://github.com/w3c/ttml2/issues/233#issuecomment-296168903
<nigel> https://github.com/w3c/ttml2/issues/397#issuecomment-313369591
<nigel> ACTION: nigel Find out where the assertion that sRGB peak white (narrow range) maps to 75% HLG originates
half-float w 2 color spaces, extended sRGB like cg colorspace, and half float scrgb (linear)
first is what chrome composites hdr in today
working colorspace prevents extended RGB canvas being clipped to sRGB
displaycolorspace (P3) on mac, scrgb on ios
avif