Playback Rate
blank = default determined rate
0 = 100%
n = .n = n% where n < 100%
-0[000...] = 100% * [ 000 ... each zero is ( * 97.2% ) ]
-3n = 1.n ... for ~111% use -31111111111 ...
where
n = a number of integers
[ ] = optional
97.2% = down one half semitone pitch
( -50 cents )
~97% = .9689999986
~111% = 1.1111111111
