I don't think you even understand the concept of in-band and out-of-band, that's not a function of the encoding. And I've written protocols aplenty in the days when not everything ran on top of HTTP, high speed serial links, with and without virtual circuits (so mux-demux) and a whole slew of others.

Just to make sure you are on the same page as the rest of us here: in-band and out-of-band is a way to distinguish sending meta information about the data stream through the same channel as the original data. You need an escape mechanism for that, so control characters and such.

Out-of-band signalling indicates that all meta information about the data stream travels through a different (virtual) circuit, in which case there can never be confusion about whether a given chunk is data or meta info.

I now understand that your point here is to be insulting.