ardour/livetrax
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Potential fix for lost VST MIDI events

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Ardour's VST MIDI buffer API does not yet implement offsets and limits.
When a cycle is split, the same midi-buffer is used for all sub-divisions
leading to duplicate, offset, events.
This commit is contained in:
Robin Gareus 2018-10-21 20:45:25 +02:00
parent 1229d50e45
commit 504ba49c6d
2 changed files with 29 additions and 1 deletions
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1
libs/ardour/ardour/vst_plugin.h
View File

@ -49,6 +49,7 @@ public:
void deactivate ();
int set_block_size (pframes_t);
bool requires_fixed_sized_buffers () const;
bool inplace_broken() const { return true; }
float default_value (uint32_t port);
float get_parameter (uint32_t port) const;

29
libs/ardour/vst_plugin.cc
View File

@ -139,6 +139,31 @@ VSTPlugin::set_block_size (pframes_t nframes)
return 0;
}
bool
VSTPlugin::requires_fixed_sized_buffers () const
{
/* This controls if Ardour will split the plugin's run()
* on automation events in order to pass sample-accurate automation
* via standard control-ports.
*
* When returning true Ardour will *not* sub-divide the process-cycle.
* Automation events that happen between cycle-start and cycle-end will be
* ignored (ctrl values are interpolated to cycle-start).
*
* Note: This does not guarantee a fixed block-size.
* e.g The process cycle may be split when looping, also
* the period-size may change any time: see set_block_size()
*/
if (get_info()->n_inputs.n_midi() > 0) {
/* we don't yet implement midi buffer offsets (for split cycles).
* Also session_vst callbacls uses _session.transport_sample() directly
* (for BBT) which is not offset for plugin cycle split.
*/
return true;
}
return false;
}
float
VSTPlugin::default_value (uint32_t which)
{
@ -709,6 +734,7 @@ VSTPlugin::connect_and_run (BufferSet& bufs,
VstEvents* v = 0;
bool valid = false;
const uint32_t buf_index_in = in_map.get(DataType::MIDI, 0, &valid);
/* TODO: apply offset to MIDI buffer and trim at nframes */
if (valid) {
v = bufs.get_vst_midi (buf_index_in);
}
@ -716,7 +742,8 @@ VSTPlugin::connect_and_run (BufferSet& bufs,
const uint32_t buf_index_out = out_map.get(DataType::MIDI, 0, &valid);
if (valid) {
_midi_out_buf = &bufs.get_midi(buf_index_out);
_midi_out_buf->silence(0, 0);
/* TODO: apply offset to MIDI buffer and trim at nframes */
_midi_out_buf->silence(nframes, offset);
} else {
_midi_out_buf = 0;
}