YUV to RGB conversion?

[NormaJ]

I want to apologize in advance if I’m proposing a dumb question. I read here almost everyday, and I have been googling too, but cannot get to figure out what’s the difference between YUV and RGB colour space. Two types of colour space, yes, but what for are each one used, and how do I know what my video source is, and when should I convert from one to another and what should I get doing so?
Also, how most used apps have to do with them (VirtualDub and Tmpgenc, mostly).

Thanks

[Alexander Gregorius]

Maybe it can help

storm_comparison.pdf

[NormaJ]

Thank you very very much
Now I can draw sort of a map of this in my mind, though my knowledge of Physics and English are not very wide, the document is clear enough to figure it out.

Still a question remains. If RGB to YUV conversion drops away 75% of the color information, does it make sense to convert back, knowing that this loss data wont be recovered?