Even if we start at time T, if the tempo point before T is ramped, we need to
adjust it's omega value based on the beat time of the following tempo point. If
we don't do this, then using that tempo to compute ::superclock_at() for
subsequent points will be incorrect.
Note: there may be an ordering issue here with Tempo/Meter points. We might
need to pass over all tempo points first, then process meters etc. Something
like that.
libs/ardour/session_state.cc:1500:13: note: in instantiation of
function template specialization 'XMLNode::set_property<unsigned long>'
requested here
libs/pbd/pbd/string_convert.h:151:11: error:
type 'unsigned long' cannot be used prior to '::' because it
has no members
The master needs to be restored first, otherwise setting
the master value with be propagated. Furthermore the
actual value is saved at the time of VCA assignment.
Restoring the vaule needs to scale by the master-reduced value.
changes in tempo can be negative (decelerando/slowing down), and thus so can _omega. We cannot call log() or its
cousins on negative values, so in this scenario use an alternate expression for "t from b" in the tempo.pdf paper
We discovered in the past that the C++ API for GSource/Glib::Source has some fatal and unfixable flaws. Copy similar
code and just use the C API for GSource instead
This is based on code from earlier commits that were later reversed, but we need some mechanism
to ensure that threads have a thread local tempo map ptr set. The big difference is that this
time we do not implement this for all instances of an AbstractUI - implementation is left to
each thread/event loop
Events in the delay-buffer must be shifted back every cycle.
Also in case of fixed-delay-lines events may not be in sequence
since events are only sorted at backend port-level.
this solves the oft-recurring problem where we assign
a beat-count of '3' or '7' because minipm mis-detected the tempo,
and that situation is vanishingly rare. it's better to assume 4 or 8
the user always has the option to change the number of beats (and
therefore the detected tempo) manually, for those clips that are
in a different time signature. but minibpm cannot be expected
to help us there.
NOTE: this is a fallback to make things 'just work' lacking any other context.
* if the tempo is detected in the filename, we use that instead
* clips that were recorded to the timeline use that bpm+timesig
* in the future we can use file-metadata (acidized wave?) instead
* this is audio-only: midi files can have an embedded timesignature
but... given no other information, experience says the vast majority
of downloaded/purchased clips will be 1,2 or 4 bars at 4/4.
