Inverting the kernel allows to “undo” a previous upsizing by compensating

#7344: Support invks in resampling filter -------------------------------------+----------------------------------- Reporter: MonoS | Owner: Type: enhancement | Status: new Priority: wish | Component: swscale Version: unspecified | Resolution: Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+----------------------------------- Comment (by MonoS): Of course, my apologies for not explaining it before: invks means kernel inversion, this is an excerpt from fmtconv documentation: the loss in high frequencies, giving a sharper and more accurate output than classic kernels, closer to the original. I find it really useful when downscaling to achieve a quick and, in my opinion, nice sharp look without messing with other sharpening filter, it may introduce some aliasing artifact but i find them better looking than the kind of artifact from sharpening filters. It may not be the correct solution in term of signal processing, but it gave me nice result in the majority of cases in a set and forget manner. -- Ticket URL: <https://trac.ffmpeg.org/ticket/7344#comment:2> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker