Clarification about surround extension

[roelofvkr]

I have a question about the surround extension.

Right now the surround extension provides an enum which includes top speakers, but it is unclear to me how they map exactly. The names CLAP_SURROUND_TFC and CLAP_SURROUND_TBC ("Front Center Height" and "Rear Center Height") suggest a speaker in front of and behind the listener but looking at the dolby 7.1.6 specification though they include (what would be) "Sides Left Height" and "Sides Right Height" speakers, which aren't included in the surround extension.

Are these two sets of speakers the same, or are they two different sets of speakers (one of which would then need to be added)?