This is in test in the
performancebranch now (in hg).
OptionWindowShortcuts out all the multi-window processing, using only the single window size already in use for the classification analysis work. So it does more sophisticated analysis than R2 but has comparable processing requirements.
The R3 code has a phase reset across bins happening gradually whenever the stretch factor returns to 1.0. Backport this to R2.
Test an intermediate processing mode using the R3 engine but with
OptionWindowShortcausing it to drop the longest window entirely and use only the other two - perhaps also shortening some of the filters as well for performance reasons. Goal would be to sound better than R2, especially for things relatively low in bass such as vocals, but run significantly faster than R3. Not sure yet how practical that is.