SoftCut: engine.rate(i,f) unable to handle negative values, under certain conditions

[dndrks]

Outside of MLR, direct application of engine.rate(i,f) causes severe playback glitching if f values are less than 0. Application of positive f values behaves as desired.

Steps to replicate:

1. load @tehn 's halfsecond.lua through Maiden
2. toggle HOLD on norns to freeze the buffer at 1x
3. execute engine.rate(1,-1) -> playback glitches
4. execute engine.rate(1,1)-> eventually, playback re-stabilizes

I'm unsure if there's a condition unique to halfsecond.lua that causes this (vs MLR), but I have also replicated in other WIP SoftCut scripts.

[dndrks]

this also might just be my complete unawareness of certain conditions that need to be met for the reverse playback to function, but since positive f values produce desired results I feel like it's something worth logging.

[catfact]

i'll have a look and take the opportunity to try (again) and fix write-head resampling

[catfact]

i'm pretty sure this artifact is from writing while reversing. in MLR the write head is never also the play head. in halfsecond the play head is also always writing, and just varying pre/rec gain levels.

i'll fix this, sorry i've been so slow, busy couple of months.