Absolute time of bars and beats

How could/should I go about getting a record (a file) of the absolute time of bars and beats during an "expressive" performance that include tempo and time signature changes and accels, ritardandos, etc.?

My goal is to align the score events (beats and bars in particular) with the generated audio file, or equivalently, to label the audio file with beats and bars with their continuously changing spacing.

Is there a way to log beat and bar timings to a file as audio is rendered (or better yet, generated from the command line)? Do I have to write a new plug-in? Of course, a MIDI file implicitly has the warping from score time units to real linear time, but loses the information associating the events with score location....

Thanks!