Ir remotes

My understanding is that Ir remotes modulate an Ir "carrier" signal
in a particular pattern to express a particular "code" corresponding to
the key pressed/held.
And, that different "chipsets" use different carriers and encodings.
Is there a front-end that is tuned to the particular carrier
in the receiver?  Or, is all of this done "digitally"?
I.e., with a fast-enough (Ir) photodetector, should I be able to
decode ANY signal from ANY "remote"?
Said another way, is the fact that a particular device ONLY
recognizes a particular remote related to its use of a particular
chipset (or, equivalently, decoding algorithm in software)?
[The former would be hard to change but the latter should be relatively easy]