Hello Ville,
On 9/3/2019 10:50 PM, Ville Syrjälä wrote:
On Tue, Sep 03, 2019 at 10:22:25PM +0530, Shashank Sharma wrote:
Blurry outputs during upscaling the buffer, is a generic problem of gfx
industry. One of the major reason behind this blurriness is the
interpolation of pixel values used by most of the upscaling hardwares.
Nearest-neighbor is a scaling mode, which works by filling in the missing
color values in the upscaled image with that of the coordinate-mapped
nearest source pixel value.
Nearest-neighbor can produce (almost) non-blurry scaling outputs when
the scaling ratio is complete integer. For example:
- input buffer resolution: 1280x720(HD)
- output buffer resolution: 3840x2160(UHD/4K)
- scaling ratio (h) = 3840/1280 = 3
scaling ratio (v) = 2160/720 = 3
In such scenarios, we should try to pick Nearest-neighbor as scaling
method when possible.
Many gaming communities have been asking for integer-mode scaling
support, some links and background:
https://software.intel.com/en-us/articles/integer-scaling-support-on-intel-graphics
http://tanalin.com/en/articles/lossless-scaling/
https://community.amd.com/thread/209107
https://www.nvidia.com/en-us/geforce/forums/game-ready-drivers/13/1002/feature-request-nonblurry-upscaling-at-integer-rat/
This patch series enables NN scaling on Intel display (ICL), when the upscaling
ratio is integer.
I think we'd probably want a property for this sort of stuff. igt
could perhaps also use it to enable crc based scaling tests.
I was initially planning to attach this to scaling mode property,
probably create a new option in there called "Integer mode scaling" or
we can use the "maintain aspect ratio" sub-option too. Do you think it
would make sense ? Or should we create a new property altogether ?
Another problem is that we currently don't expose the panel fitter
for external displays so this would be limited to eDP/DSI only.
I have a branch that implements borders (for underscan) for DP/HDMI
which is at least moving the code a little bit into a direction where
we could consider exposing the panel fitter for external displays.
This would be very interesting, do you have any plans to publish this soon ?
- Shashank
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