Is it correct to state that many people confuse rate and quantity when talking about chroma subsampling? I feel people understand 4:1:1 as different quantities when it is really about different rates, or is this just an self created illusion?

There's a lot of confusion. A lot of people say "colour space" when they mean "chroma sampling". Others get 4:1:1 and 4:2:0 mixed up, and others think 4:1:1 is lower quality colour than 4:2:2, when really, it's just lower resolution colour!

http://www.lafcpug.org/Tutorials/basic_chroma_sample.html

Is an article I wrote to help reduce confusion!

Graeme