This fixes an issue when switching formats.
ExportFormatDialog::update_selection iterates e.g. WAV BWV.
If BWV was selected and a user selects WAV the following happpens
1. WAV is selected
2. BWV is deselected
3. Since BWF and WAV are the same format, ExportFormatManager
deselects WAV
This fixes a bug introduced in d06a0d9c9d. The MIDI data
has to be written first, otherwise the CC-event do not exit
and MidiModel::source_interpolation_changed() crashes.
There were many logical errors in the previous implementation. This one is
simpler to read, and appears to work much better.
It also allows the caller to specify the quarter-note subdivision to use when
generating the grid, rather than choosing only between some bar modulo or
quarter notes.
It can happen that the main AlsaAudioBackend::_device_reservation
is still busy while I/O devices are set. In this case a
dedicated AlsaDeviceReservation needs to be used which can fail
silently.
A common example is disconnecting a USB device while it is in
use. The Halted signal can show the session dialog, which calls
set_input_device_name before the device reservation of the
unplugged device terminated.
ALSA backend modified the internal state when different devices
were used, re-assigning one (usually input-device) to "None"
when it's resampled. This lead to EngineHints not matching the
EngineState, and autostart was disabled, and a dialog
"Engine I/O device has changed since you last opened this session."
Archiving creates a dedicated mono file for each Source.
When the original session has (embedded) stereo files, the
channel needs to be temporarily set to 0.
introducing a new time signature that uses non-quarter notes as the denominator
will move the beat position a given BBT time (since the middle "B" of BBT
refers to "beats" given by the denominator, not quarters).
