2016-07-04, 10:13
The Pi series use a Mitchell-Netravali filter for upscaling - which offers a decent quality solution (and is, I believe, implemented in the GPU). You don't have other choices - unlike other platforms.
https://www.cs.utexas.edu/~fussell/cours...tchell.pdf
I know a lot of people like Lanczos3 as a scaling algorithm, but for me it appears to add too many ringing/aliasing artefacts, giving video an artificially sharpened look. (A bit like having the Sharpness control on your TV at anything other than 0 - and nobody should EVER have the sharpness control at anything above 0 (*) Always check a decent frequency grating and set your sharpness so that fine detail isn't masked by artificial edge enhancement...)
(*) Unless you have a sharpness control where 50% = no sharpening and 0% = artificial softening - but these are rare.
https://www.cs.utexas.edu/~fussell/cours...tchell.pdf
I know a lot of people like Lanczos3 as a scaling algorithm, but for me it appears to add too many ringing/aliasing artefacts, giving video an artificially sharpened look. (A bit like having the Sharpness control on your TV at anything other than 0 - and nobody should EVER have the sharpness control at anything above 0 (*) Always check a decent frequency grating and set your sharpness so that fine detail isn't masked by artificial edge enhancement...)
(*) Unless you have a sharpness control where 50% = no sharpening and 0% = artificial softening - but these are rare.