How much of code deletion comes from switching to a two-step mapping between DirectShow and Media Foundation formats, versus changing the format we pass over the wire?
I don't know? Most of it?
Most of it results from the two-step mapping, or from changing the format we pass over the wire?
I mean, it matters. There's an inherent tradeoff in both cases (besides code churn of course). Using a two-step mapping risks losing information (at least if we use the builtin methods, and there's no point if we're not going to do that), even if that's not something we notice now it might come up later. Similarly wg_format was something that was specifically meant as a compact, neutral, well-defined representation, with no extra information, that's easy to pass over the wire. These two things can be changed independently, and knowing how much of a benefit we get from each helps to evaluate whether each change is something we want.
(Also, why rename wg_format to wg_media_type?)
It just makes the transition easier.
How does renaming a struct make anything easier?