ITU-R BS.1770 https://www.itu.int/rec/R-REC-BS.1770
K-rating $\ne$ K-system!
VU .. volume unit
LU .. loudness unit
LUFS
QPPM vs. "true peak" (with oversampling)
EBU R 128 https://tech.ebu.ch/loudness
-1 dBTP
Implementation of ITU-R BS.1770-4 loudness algorithm in Python: https://github.com/csteinmetz1/pyloudnorm
Python library: http://mikrolax.github.io/loudnessPlotter/
C++ library with Python bindings: https://github.com/deeuu/loudness