On Tue, 12 Mar 2024 16:26:00 +0200 Pekka Paalanen <pekka.paalanen@xxxxxxxxxxxxx> wrote: > On Tue, 12 Mar 2024 08:30:34 +0000 > "Garg, Nemesa" <nemesa.garg@xxxxxxxxx> wrote: > > > This KMS property is not implementing any formula > > Sure it is. Maybe Intel just does not want to tell what the algorithm > is, or maybe it's even patented. > > > and the values > > that are being used are based on empirical analysis and certain > > experiments done on the hardware. These values are fixed and is not > > expected to change and this can change from vendor to vendor. The > > client can choose any sharpness value on the scale and on the basis > > of it the sharpness will be set. The sharpness effect can be changed > > from content to content and from display to display so user needs to > > adjust the optimum intensity value so as to get good experience on > > the screen. > > > > IOW, it's an opaque box operation, and there is no way to reproduce its > results without the specific Intel hardware. Definitely no way to > reproduce its results in free open source software alone. > > Such opaque box operations can only occur after KMS blending, at the > CRTC or later stage. They cannot appear before blending, not in the new > KMS color pipeline design at least. The reason is that the modern way > to use KMS planes is opportunistic composition off-loading. > Opportunistic means that userspace decides from time to time whether it > composes the final picture using KMS or some other rendering method > (usually GPU and shaders). Since userspace will arbitrarily switch > between KMS and render composition, both must result in the exact same > image, or end users will observe unwanted flicker. > > Such opaque box operations are fine after blending, because there they > can be configured once and remain on forever. No switching, no flicker. If you want to see how sharpness property would apply in Wayland design, it would be in step 5 "Adjust (settings UI)" of https://gitlab.freedesktop.org/pq/color-and-hdr/-/blob/main/doc/color-management-model.md#compositor-color-management-model To relate that diagram to KMS color processing, you can identify step 3 "Compose" as the KMS blending step. Everything before step 3 happens in KMS plane color processing, and steps 4-5 happen in KMS CRTC color processing. Sharpening would essentially be a "compositor color effect", it just happens to be implementable only by specific Intel hardware. If a color effect is dynamic or content-dependant, it will preclude colorimetric monitor calibration. Thanks, pq > Where does "sharpeness" operation occur in the Intel color processing > chain? Is it before or after blending? > > What kind of transfer characteristics does it expect from the image, > and can those be realized with KMS CRTC properties if KMS is configured > such that the blending happens using some other characteristics (e.g. > blending in optical space)? > > What about SDR vs. HDR imagery? > > > Thanks, > pq > > > > -----Original Message----- > > > From: dri-devel <dri-devel-bounces@xxxxxxxxxxxxxxxxxxxxx> On Behalf Of Simon > > > Ser > > > Sent: Monday, March 4, 2024 7:46 PM > > > To: Garg, Nemesa <nemesa.garg@xxxxxxxxx> > > > Cc: Pekka Paalanen <pekka.paalanen@xxxxxxxxxxxxx>; intel- > > > gfx@xxxxxxxxxxxxxxxxxxxxx; dri-devel@xxxxxxxxxxxxxxxxxxxxx; G M, Adarsh > > > <adarsh.g.m@xxxxxxxxx> > > > Subject: RE: [RFC 0/5] Introduce drm sharpening property > > > > > > On Monday, March 4th, 2024 at 15:04, Garg, Nemesa <nemesa.garg@xxxxxxxxx> > > > wrote: > > > > > > > This is generic as sharpness effect is applied post blending. > > > > Depending on the color gamut, pixel format and other inputs the image > > > > gets blended and once we get blended output it can be sharpened based > > > > on strength value provided by the user. > > > > > > It would really help if you could provide the exact mathematical formula applied > > > by this KMS property. >
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