Each directory applies a differently styled AGC
(automatic gain control) and/or clipping threshold
to the fk movies.

AGC:
max - gain applied so that the maximum of the fk image stays at 0db
median - gain applied so that the median of the fk image stays at 0db

Clipping:
Xdb - for median this clips the image from +X to 0 dB
    - for max this clips the fk image from 0 to -X dB


Median AGC keeps the background noise level near 0dB which makes the
movies less sporadic than max-styled AGC when plane wave sources are
coming and going.  But it also clips peaks above the set upper limit.
That is why there are multiple clipping thresholds for the median
output: 4dB focuses on weaker noise sources (clipping the stronger
ones) while 10dB will focus a bit more on the stronger noise sources.

I tend to look at median-4db first and if the clipping is too strong I
look at median-10db.