On 2025-01-17 04:06, Pekka Paalanen wrote: > On Thu, 16 Jan 2025 10:56:22 +0200 > Pekka Paalanen <pekka.paalanen@xxxxxxxxxxxxx> wrote: > >> On Thu, 19 Dec 2024 21:33:37 -0700 >> Alex Hung <alex.hung@xxxxxxx> wrote: >> >>> From: Harry Wentland <harry.wentland@xxxxxxx> >>> >>> The BT.709 and BT.2020 OETFs are the same, the only difference >>> being that the BT.2020 variant is defined with more precision >>> for 10 and 12-bit per color encodings. >>> >>> Both are used as encoding functions for video content, and are >>> therefore defined as OETF (opto-electronic transfer function) >>> instead of as EOTF (electro-optical transfer function). >>> >>> Signed-off-by: Alex Hung <alex.hung@xxxxxxx> >>> Signed-off-by: Harry Wentland <harry.wentland@xxxxxxx> >> >> Hi, >> >> why would a display system ever use BT.2020 or BT.709 OETF or its >> inverse? > > Sorry, this is more for my own curiosity, not an argument against the > patch. Since hardware designers decided to incorporate these curves > explicitly, what use was in mind? It's likely something I have > overlooked. > I'm not entirely sure myself, but gamescope does use it for displaying game streaming content. https://github.com/ValveSoftware/gamescope/blob/2f88849ac9dc7da5c678d5d7d3e9b58f38add1bf/src/Backends/DRMBackend.cpp#L2509 Harry > > Thanks, > pq
