Technically they are not the same with YPbPr being a descriptor for anaolog component and YCbCr being for a digital component signal but the Japs got things screwed up and interchange these. Rather than change the Japs, they are normally accepted to be the same thing.
For a detailed explaination, go to
[Link: hometown.aol.com] I haven't used this site in a while, but it is very usefull and, as you will find, very boring and sometimes you have to read it a couple of times to catch on!
Have fun,
randy