quietvoid / dovi_tool

dovi_tool is a CLI tool combining multiple utilities for working with Dolby Vision.
MIT License
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Profile 8.4 #205

Closed joaoserra closed 1 year ago

joaoserra commented 1 year ago

Hi,

This issue is not about dovi_tool, mas I'm hoping you can help me with one question.

I'm trying to understand how profile 8.4 works. As far as I know, this is only used by the iPhone. (at least, so far) If I understood it correctly, profile 8.4 is HLG+RPU. But HLG is a scene-referred system and not based on absolute values like PQ, so what's the point of metadata?

So what will a Display do with a HLG bitstream and Dolby Metadata?Maybe the Display converts the HLG to PQ with a 1000nits peak (using the algorithm described in in https://www.bbc.co.uk/rd/sites/50335ff370b5c262af000004/assets/592eea8006d63e5e5200f90d/BBC_HDRTV_PQ_HLG_Transcode_v2.pdf / BT.2390) and then apply the rpu metadata?  But what metadata levels does profile 8.4 contain? Maybe only basic metadata like L1? I'm not sure the rest of the metadata levels can be calculated in real-time video recording. Thanks!