Algorithm used when adjusting sample properties?

Just curious, how Renoiseperform up/down sampling when adjusting sample rates at the editor?

I assume it’s truncation down and sinc up?

Yes, we’re using a specialized FIR for that, based on:https://ccrma.stanford.edu/~jos/pdf/optfir.pdf

It’s only used when offline resampling, as it happens when changing the sample rates in the sample editor.