What about this old post on russian forum?
http://4pda.ru/forum/index.php?s=&showtopic=764777&view=findpost&p=71591829
Thats about “Alfawise H96 Pro” on “aml_7.1_s912_q9377_S912_KDMC_mac-2017-0830” firmware and Youtube HDR playback.
Screenshots: http://4pda.ru/forum/index.php?act=findpost&pid=71591829&anchor=Spoil-71591829-2