ybr.py

import numpy

Kb = 0.114
Kr = 0.299

full = numpy.array([
  [1.0, 0.0, 2.0*(1.0-Kr) ],
  [1.0, -2.0*Kb*(1.0-Kb)/(1.0-Kr-Kb), -2.0*Kr*(1.0-Kr)/(1.0-Kr-Kb) ],
  [1.0, 2.0*(1.0-Kb), 0.0 ]
])

print("YBR_FULL to RGB")
print(full)
print("RGB to YBR_FULL")
print(numpy.linalg.inv(full))

partial = numpy.array(full)
partial[:,0] *= 255.0/219.0;
partial[:,1] *= 255.0/224.0;
partial[:,2] *= 255.0/224.0;

print("YBR_PARTIAL to RGB")
print(partial)
print("RGB to YBR_PARTIAL")
print(numpy.linalg.inv(partial))