Constant KNEE_CONVENTION 

pub const KNEE_CONVENTION: &str = "the note-off knee is read on the linear amplitude of the amp \
proxy, from the first frame within 1 dB of the peak to 25 ms before the note's end; at each split \
a line over up to 100 ms before it and one over up to 200 ms after it, stopping where the level \
falls under 2 % of the mean before it, fit against one line over both; a split counts when the \
right line is steeper by half the mean before it per second, falls by half that mean over its \
side, and the two lines leave at most half the squared error of one; splits that count in a row \
form a corner, and the split with the largest gain wins it; a later corner replaces an earlier one \
when the median size of the second difference of the level in dB between them, 10 ms each way, is \
at most 0.4 dB and the level after it rises by at most a twentieth of the mean before it, read as \
is over its first 20 ms and as the mean over every 20 ms span, up to what follows the note; a later \
corner past what follows the note replaces none when the mean over the last 10 ms before that point \
lies under 2 % of the earlier corner's mean before it, the mean before the later corner lies at \
least 1.25 times that level and the left line's end lies above it, on the amp proxy or, when the \
note is stripped, on the proxy before the pump's strip; the knee is where the left line crosses a line over the first 10 ms after the split, or the split itself \
when that crossing lies outside the two lines; when the level stays at 85 % or more of the left \
line's end for over 10 ms more, the knee is where a line over its fall from there to half that \
level crosses that level; null when no split counts, as for a pluck that decays at one rate; \
note_off_offset_s is the note's end in the note list, or the stem's end when that comes first, minus its \
knee, over the pooled notes with a knee";

The convention of the note-off knee and its offset.