This is to allow passing the EventType to the Buffer, using a
consistent {[Time], Type, size, data} API, that is equivalent
for all classes.
This is particularly useful for Lua scripts and plugin UIs
than can call `write_immediate_event()` while being ignorant
where the data is routed to (MIDI tracks, plugins, processors).
The motivation for this is to determine if a given event
originates from a user-controlled live input controller or
from playback from disk or a MIDI file.
This distinction is required for VST3 MIDI learn.
This is required. From the "RestartFlags" documentation:
> kLatencyChanged:
> Latency has changed The plug informs the host that its latency
> has changed, getLatencySamples should return the new latency after
> setActive (true) was called The host has to deactivate and reactivate
> the plug-in, then afterwards the host could ask for the current
> latency (getLatencySamples) see IAudioProcessor::getLatencySamples
This can happen during pre-roll when buffers are filled
to start audible playback at zero.
While the position argument is signed for all plugin-standards,
it seems that some do not support negative timestamps before
00:00:00:00. (e.g. https://github.com/falkTX/Carla/issues/1236)
Furthermore TempoMap::bbt_at_sample() returns 0 for all negative
timestamps, but it was possible tthat tempo-map transmission,
as well as beat-position returned negative values.
When the engine is restarted, ports are re-established,
and previously queued port-connections need to be cleared.
This caused a bug:
* when the engine is stopped all ports are disconnected.
_port_connection_queue contains all disconnections
* engine is stopped so _port_connection_queue is not processed
* engine-restart re-etablishes ports and appends those connections
to _port_connection_queue
* process-callback processes the list in **reverse** order
```
while (!_port_connection_queue.empty ()) {
_port_connection_queue.pop_back ();
}
```
* ARDOUR::PortManager::connect_callback() is first called
with connected() and the disconnected()
* All ports are assumed to not be connected
Port::_externally_connected == 0 for all ports
Result:
* vari-speed playback resampling does not work (only external
I/O is reampled), split cycles processing (looping) fails
since AudioPort::get_audio_buffer() does not apply the
_global_port_buffer_offset
Previously when locating process_can_proceed() was set to true,
and routes were not processed while transport states are cleared.
As a result live input was also not processed.
This is no longer needed because the DiskReader handles seeking
directly.
This fixes segfaults as well as corrupt listes when copy/pasting
due to invalid iterators.
::mark_dirty() must be called with WriterLock, and
::rt_safe_earliest_event_linear_unlocked() must not be called
while _events is being modified. The Sequence iterator
(only user of that function) does not ensure this. Only the
sequence read-lock is taken.
When recording audio, simply not writing to the ringbuffer
offsets the recording accordingly.
When recording MIDI, absolute timestamps are used, so the recording
has to be offset by the accumulated difference.
Previously this went unnoticed because tests using the Dummy
backend the accumulated offset never exceeded 1 cycle.
