Doom9's Forum - View Single Post - A different approach to truncated sinc filters

TheFluff · 5th September 2018, 18:11

I'm a bit confused by your terminology and I'm not a DSP guru, but as far as I understand it, if you want a sinc filter where the coeffs sum to exactly 1, you pretty much want Lanczos, because that's pretty much what Lanczos is. Getting the coeffs to sum to exactly 1 in a real implementation (of any resizer) with all its pesky numerical precision issues requires dithering them though, and even then there might still be a small residual error. See for example zimg's take on it.

5th September 2018, 18:11	#4 \| Link
TheFluff Excessively jovial fellow Join Date: Jun 2004 Location: rude Posts: 1,100	I'm a bit confused by your terminology and I'm not a DSP guru, but as far as I understand it, if you want a sinc filter where the coeffs sum to exactly 1, you pretty much want Lanczos, because that's pretty much what Lanczos is. Getting the coeffs to sum to exactly 1 in a real implementation (of any resizer) with all its pesky numerical precision issues requires dithering them though, and even then there might still be a small residual error. See for example zimg's take on it. Last edited by TheFluff; 5th September 2018 at 18:15.