Light emission velocities are the emitter's velocity from a preferred frame
Light emission velocities & corresponding measurement scales vary by Lorentz factors in a passive (non-dynamical) spacetime.
A Theory of Light Relativity (TLR): tested yet unchallenged
TLR is a novel relativity physics in which observers use abelian (commuting) spacetime-based equations to interpret the experimental foundations of physics. Observers' measurement perspectives of both the cosmos and particle physics are consistent with a unified quantum electrodynamics model that eliminates singularities, unifies all forces, complies with Mach's principle, and resolves (with plausible physical paradigms) many of the outstanding conundrums in post-Newtonian physics. TLR's QED-based models are consistent with the experimental foundations of post-Newtonian physics because their measurement equations can, in most cases, be derived directly from corresponding equations derived under Einstein's special and general theories of relativity. The exceptions to this yield viable tests for TLR's models.