awxkee
commented
10 months ago Hi, can you implement bitmap scaling based on ffmpeg libswscale, because it can choose between some algorhytms, like bicubic, bilenear, lancoz and others, if you can here is abandoned project that support only two archs and not starts on api 24 and abov
Hello there,
The project as default using a provided libheif scaling when it needs to be downscaled that is bicubic algorithm.
Not really sure that is good idea trying to compile part of FFmpeg for this one.
In jxl-coder you may found a class XScaler.cpp that contains already done scaling for float16 bitmap format and argb 8-bit with ready to go algorithms - nearest neighbor, bcubic, bilinear, Mitchell-Netravalli, Catmull Rom, lanczos and hann window and hermite spline and some math tricks like fast sin/cos via chebyshev polynoms and etc. And I may say that algorithms not worse than libswscale especially for arm64 platforms.
If you are thinking about dedicated library, I'm not really into it, but you may easily find all the required code in my projects.
I may say you before you start that default android scaling is bilinear was chosen for a reason. It has awesome performance on a not quite powerful devices and do especially well when you need a scale that not changing image dimensions too much. There are not so many real world cases an android when you need a Spline that do really well when you need a scale more than 2x or original dimensions and have 2+ times performance degradation against bilinear. And also not so much cases when you need a Lanczos that do well on scale like 0.1x of original dimensions and require computational power at least 3-4 times more than bilinear
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Hi, can you implement bitmap scaling based on ffmpeg libswscale, because it can choose between some algorhytms, like bicubic, bilenear, lancoz and others, if you can here is abandoned project that support only two archs and not starts on api 24 and abov