2 * Copyright (C) 2013-2014 Robin Gareus <robin@gareus.org>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 #include "ardour/mididm.h"
20 #include "ardour/port_engine.h"
22 using namespace ARDOUR;
24 MIDIDM::MIDIDM (framecnt_t sample_rate)
25 : _sample_rate (sample_rate)
26 , _monotonic_cnt (sample_rate)
27 , _last_signal_tme (0)
30 , _min_delay (INT32_MAX)
40 int MIDIDM::process (pframes_t nframes, PortEngine &pe, void *midi_in, void *midi_out)
45 obuf[1] = (_monotonic_cnt) & 0x7f;
46 obuf[2] = (_monotonic_cnt >> 7) & 0x7f;
48 pe.midi_clear(midi_out);
49 pe.midi_event_put (midi_out, 0, obuf, 3);
51 /* process incoming */
52 const pframes_t nevents = pe.get_midi_event_count (midi_in);
53 for (pframes_t n = 0; n < nevents; ++n) {
57 pe.midi_event_get (timestamp, size, &buf, midi_in, n);
59 if (size != 3 || buf[0] != 0xf2 ) continue;
61 _last_signal_tme = _monotonic_cnt;
63 /* calculate time difference */
64 #define MODX (16384) // 1<<(2*7)
65 #define MASK (0x3fff) // MODX - 1
66 const int64_t tc = (_monotonic_cnt + timestamp) & MASK;
67 const int64_t ti = (buf[2] << 7) | buf[1];
68 const int64_t tdiff = (MODX + tc - ti) % MODX;
70 /* running variance */
71 if (_cnt_total == 0) {
74 const double var_m1 = _var_m;
75 _var_m = _var_m + ((double)tdiff - _var_m) / (double)(_cnt_total + 1);
76 _var_s = _var_s + ((double)tdiff - _var_m) * ((double)tdiff - var_m1);
78 /* average and mix/max */
81 _avg_delay = _dly_total / _cnt_total;
82 if (tdiff < _min_delay) _min_delay = tdiff;
83 if (tdiff > _max_delay) _max_delay = tdiff;
86 _monotonic_cnt += nframes;