Converts rgb to ycbcr (YUV - Luminance + Chromanance)

rgb2ycbcr.py

#http://www.picturetopeople.org/p2p/picture_to_people_colors.p2p/color_converter?color_space=RGB&color_channel1=0&color_channel2=0&color_channel3=0
#https://msdn.microsoft.com/en-us/library/ff635643.aspx

#rgb range   - [0,255]
#y range     - [0,255]
#cb,cr range - [-128,127]

import sys 
import time
#r = int(sys.argv[1])
#g = int(sys.argv[2])
#b = int(sys.argv[3])
#print ("RGB: ", r, g, b)
#y = 0.299 * r + 0.587 * g + 0.114 * b
#cb = -0.168935 * r + -0.331665 * g + 0.50059 * b
#cr = 0.499813 * r + -0.418531 * g + -0.081282 * b
#y = int(y)
#cb = int(cb)
#cr = int(cr)
#print ("YCbCr: ", y, cb, cr)

for i in range(0,256):
        for j in range(0,256):
                for k in range(0,256):
                    r = i
                    g = j
                    b = k
                    y = 0.299 * r + 0.587 * g + 0.114 * b
                    cb = -0.168935 * r + -0.331665 * g + 0.50059 * b
                    cr = 0.499813 * r + -0.418531 * g + -0.081282 * b
                    y = int(y)
                    cb = int(cb)
                    cr = int(cr)
                    print ("rgb=>", r, g, b," ycbcr=>", y, cb, cr)
                    time.sleep(0.5)
                    if (y < 0 or y > 255 or cb < -128 or cb > 127 or cr < -128 or cb > 127):
                        print ("FAIL! YCbCr: ", y, cb, cr) # doesn't fail tho