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livetrax/libs/ardour/midi_clock_slave.cc
Robin Gareus 3e6295f538
Fix MIDI Clock slave
* take port latency into account
* fix DLL initialization, and initial speed calculation
* igonre out of bounds BPM

the DLL bandwidth still needs to be tweaked, likewise the
hardcoded 1st order LPF to track BPM (vs speed).
2020-05-27 23:59:27 +02:00

442 lines
14 KiB
C++

/*
* Copyright (C) 2008-2013 Hans Baier <hansfbaier@googlemail.com>
* Copyright (C) 2009-2010 Carl Hetherington <carl@carlh.net>
* Copyright (C) 2009-2012 David Robillard <d@drobilla.net>
* Copyright (C) 2009-2019 Paul Davis <paul@linuxaudiosystems.com>
* Copyright (C) 2012-2013 Robin Gareus <robin@gareus.org>
* Copyright (C) 2013-2018 John Emmas <john@creativepost.co.uk>
* Copyright (C) 2015-2016 Nick Mainsbridge <mainsbridge@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <cmath>
#include <errno.h>
#include <sys/types.h>
#include <unistd.h>
#include "pbd/error.h"
#include "pbd/failed_constructor.h"
#include "pbd/pthread_utils.h"
#include "pbd/convert.h"
#include "midi++/port.h"
#include "ardour/audioengine.h"
#include "ardour/debug.h"
#include "ardour/midi_buffer.h"
#include "ardour/midi_port.h"
#include "ardour/session.h"
#include "ardour/tempo.h"
#include "ardour/transport_master.h"
#include "ardour/transport_master_manager.h"
#include "pbd/i18n.h"
using namespace std;
using namespace ARDOUR;
using namespace MIDI;
using namespace PBD;
#define ENGINE AudioEngine::instance()
MIDIClock_TransportMaster::MIDIClock_TransportMaster (std::string const & name, int ppqn)
: TransportMaster (MIDIClock, name)
, ppqn (ppqn)
, midi_clock_count (0)
, _running (false)
, _bpm (0)
{
}
MIDIClock_TransportMaster::~MIDIClock_TransportMaster()
{
port_connections.drop_connections ();
}
void
MIDIClock_TransportMaster::init ()
{
midi_clock_count = 0;
current.reset ();
resync_latency (false);
}
void
MIDIClock_TransportMaster::connection_handler (boost::weak_ptr<ARDOUR::Port> w0, std::string n0, boost::weak_ptr<ARDOUR::Port> w1, std::string n1, bool con)
{
TransportMaster::connection_handler(w0, n0, w1, n1, con);
boost::shared_ptr<Port> p = w1.lock ();
if (p == _port) {
resync_latency (false);
}
}
void
MIDIClock_TransportMaster::create_port ()
{
if ((_port = create_midi_port (string_compose ("%1 in", _name))) == 0) {
throw failed_constructor();
}
}
void
MIDIClock_TransportMaster::set_session (Session* s)
{
TransportMaster::set_session (s);
TransportMasterViaMIDI::set_session (s);
port_connections.drop_connections();
/* only connect to signals if we have a proxy, because otherwise we
* cannot interpet incoming data (no tempo map etc.)
*/
if (_session) {
parser.timing.connect_same_thread (port_connections, boost::bind (&MIDIClock_TransportMaster::update_midi_clock, this, _1, _2));
parser.start.connect_same_thread (port_connections, boost::bind (&MIDIClock_TransportMaster::start, this, _1, _2));
parser.contineu.connect_same_thread (port_connections, boost::bind (&MIDIClock_TransportMaster::contineu, this, _1, _2));
parser.stop.connect_same_thread (port_connections, boost::bind (&MIDIClock_TransportMaster::stop, this, _1, _2));
parser.position.connect_same_thread (port_connections, boost::bind (&MIDIClock_TransportMaster::position, this, _1, _2, _3, _4));
reset (true);
}
}
void
MIDIClock_TransportMaster::pre_process (MIDI::pframes_t nframes, samplepos_t now, boost::optional<samplepos_t> session_pos)
{
/* Read and parse incoming MIDI */
DEBUG_TRACE (DEBUG::MidiClock, string_compose ("preprocess with lt = %1 @ %2, running ? %3\n", current.timestamp, now, _running));
_midi_port->read_and_parse_entire_midi_buffer_with_no_speed_adjustment (nframes, parser, now);
/* no clock messages ever, or no clock messages for 1/4 second ? conclude that its stopped */
if (!current.timestamp || one_ppqn_in_samples == 0 || (now > current.timestamp && ((now - current.timestamp) > (ENGINE->sample_rate() / 4)))) {
_bpm = 0.0;
_running = false;
_current_delta = 0;
midi_clock_count = 0;
DEBUG_TRACE (DEBUG::MidiClock, string_compose ("No MIDI Clock messages received for some time, stopping! ts = %1 @ %2 ppqn = %3\n", current.timestamp, now, one_ppqn_in_samples));
return;
}
if (session_pos) {
const samplepos_t current_pos = current.position + ((now - current.timestamp) * current.speed);
_current_delta = current_pos - *session_pos;
} else {
_current_delta = 0;
}
DEBUG_TRACE (DEBUG::MidiClock, string_compose ("speed_and_position: speed %1 should-be %2 transport %3 \n", current.speed, current.position, _session->transport_sample()));
}
void
MIDIClock_TransportMaster::calculate_one_ppqn_in_samples_at(samplepos_t time)
{
const double samples_per_quarter_note = _session->tempo_map().samples_per_quarter_note_at (time, ENGINE->sample_rate());
one_ppqn_in_samples = samples_per_quarter_note / double (ppqn);
// DEBUG_TRACE (DEBUG::MidiClock, string_compose ("at %1, one ppqn = %2 [spl] spqn = %3, ppqn = %4\n", time, one_ppqn_in_samples, samples_per_quarter_note, ppqn));
}
ARDOUR::samplepos_t
MIDIClock_TransportMaster::calculate_song_position(uint16_t song_position_in_sixteenth_notes)
{
samplepos_t song_position_samples = 0;
for (uint16_t i = 1; i <= song_position_in_sixteenth_notes; ++i) {
// one quarter note contains ppqn pulses, so a sixteenth note is ppqn / 4 pulses
calculate_one_ppqn_in_samples_at(song_position_samples);
song_position_samples += one_ppqn_in_samples * (samplepos_t)(ppqn / 4);
}
return song_position_samples;
}
void
MIDIClock_TransportMaster::calculate_filter_coefficients (double qpm)
{
/* Paul says: I don't understand this computation of bandwidth
*/
const double bandwidth = 2.0 / qpm;
/* Frequency of the clock messages is ENGINE->sample_rate() / * one_ppqn_in_samples, per second or in Hz */
const double freq = (double) ENGINE->sample_rate() / one_ppqn_in_samples;
const double omega = 2.0 * M_PI * bandwidth / freq;
b = 1.4142135623730950488 * omega; // sqrt (2.0) * omega
c = omega * omega;
DEBUG_TRACE (DEBUG::MidiClock, string_compose ("DLL coefficients: bw:%1 omega:%2 b:%3 c:%4\n", bandwidth, omega, b, c));
}
void
MIDIClock_TransportMaster::update_midi_clock (Parser& /*parser*/, samplepos_t timestamp)
{
samplepos_t elapsed_since_start = timestamp - first_timestamp;
calculate_one_ppqn_in_samples_at (current.position);
DEBUG_TRACE (DEBUG::MidiClock, string_compose ("clock count %1, sbp %2\n", midi_clock_count, current.position));
if (midi_clock_count == 0) {
/* second 0xf8 message after start/reset has arrived */
first_timestamp = timestamp;
current.update (0, timestamp, 0);
DEBUG_TRACE (DEBUG::MidiClock, string_compose ("first clock message after start received @ %1\n", timestamp));
midi_clock_count++;
} else if (midi_clock_count == 1) {
/* second 0xf8 message has arrived. we can now estimate QPM
* (quarters per minute, and fully initialize the DLL
*/
e2 = timestamp - current.timestamp;
const samplecnt_t samples_per_quarter = e2 * 24;
double bpm = (ENGINE->sample_rate() * 60.0) / samples_per_quarter;
if (bpm < 1 || bpm > 999) {
current.update (0, timestamp, 0);
midi_clock_count = 1; /* start over */
DEBUG_TRACE (DEBUG::MidiClock, string_compose ("BPM is out of bounds (%1)\n", timestamp, current.timestamp));
} else {
_bpm = bpm;
calculate_filter_coefficients (_bpm);
/* finish DLL initialization */
t0 = timestamp;
t1 = t0 + e2; /* timestamp we predict for the next 0xf8 clock message */
midi_clock_count++;
current.update (one_ppqn_in_samples + midi_port_latency.max, timestamp, 0);
}
} else {
/* 3rd or later MIDI clock message. We can now compute actual
* speed (and tempo) with the DLL
*/
double e = timestamp - t1; // error between actual time of arrival of clock message and our predicted time
t0 = t1;
t1 += b * e + e2;
e2 += c * e;
const double samples_per_quarter = (timestamp - current.timestamp) * 24.0;
const double instantaneous_bpm = (ENGINE->sample_rate() * 60.0) / samples_per_quarter;
const double predicted_clock_interval_in_samples = (t1 - t0);
/* _speed is relative to session tempo map */
double speed = predicted_clock_interval_in_samples / one_ppqn_in_samples;
/* _bpm (really, _qpm) is absolute */
/* detect substantial changes in apparent tempo (defined as a
* change of more than 20% of the current tempo.
*/
const double lpf_coeff = 0.063;
if (fabs (instantaneous_bpm - _bpm) > (0.20 * _bpm)) {
_bpm = instantaneous_bpm;
} else {
_bpm += lpf_coeff * (instantaneous_bpm - _bpm);
}
calculate_filter_coefficients (_bpm);
// need at least two clock events to compute speed
if (!_running) {
DEBUG_TRACE (DEBUG::MidiClock, string_compose ("start mclock running with speed = %1\n", (t1 - t0) / one_ppqn_in_samples));
_running = true;
}
midi_clock_count++;
current.update (current.position + one_ppqn_in_samples, timestamp, speed);
if (TransportMasterManager::instance().current().get() == this) {
_session->maybe_update_tempo_from_midiclock_tempo (_bpm);
}
}
DEBUG_TRACE (DEBUG::MidiClock, string_compose (
"clock #%1 @ %2 should-be %3 transport %4 appspeed %6 "
"read-delta %7 should-be-delta %8 t1-t0 %9 t0 %10 t1 %11 sample-rate %12 engine %13 running %14\n",
midi_clock_count, // #
elapsed_since_start, // @
current.position, // should-be
_session->transport_sample(), // transport
(t1 - t0) / one_ppqn_in_samples, // appspeed
timestamp - current.timestamp, // read delta
one_ppqn_in_samples, // should-be delta
(t1 - t0), // t1-t0
t0, // t0 (current position)
t1, // t1 (expected next pos)
ENGINE->sample_rate(), // framerate
ENGINE->sample_time(),
_running
));
}
void
MIDIClock_TransportMaster::start (Parser& /*parser*/, samplepos_t timestamp)
{
DEBUG_TRACE (DEBUG::MidiClock, string_compose ("MIDIClock_TransportMaster got start message at time %1 engine time %2 transport_sample %3\n", timestamp, ENGINE->sample_time(), _session->transport_sample()));
if (!_running) {
reset(true);
_running = true;
current.update (_session->transport_sample(), timestamp, 0);
}
}
void
MIDIClock_TransportMaster::reset (bool with_position)
{
DEBUG_TRACE (DEBUG::MidiClock, string_compose ("MidiClock Master reset(): calculated filter for period size %2\n", ENGINE->samples_per_cycle()));
if (with_position) {
current.update (_session->transport_sample(), 0, 0);
} else {
current.reset ();
}
_running = false;
_current_delta = 0;
}
void
MIDIClock_TransportMaster::contineu (Parser& /*parser*/, samplepos_t /*timestamp*/)
{
DEBUG_TRACE (DEBUG::MidiClock, "MIDIClock_TransportMaster got continue message\n");
_running = true;
}
void
MIDIClock_TransportMaster::stop (Parser& /*parser*/, samplepos_t timestamp)
{
DEBUG_TRACE (DEBUG::MidiClock, "MIDIClock_TransportMaster got stop message\n");
if (_running) {
_running = false;
// we need to go back to the last MIDI beat (6 ppqn)
// and lets hope the tempo didnt change in the meantime :)
// begin at the should be position, because
// that is the position of the last MIDI Clock
// message and that is probably what the master
// expects where we are right now
//
// find out the last MIDI beat: go back #midi_clocks mod 6
// and lets hope the tempo didnt change in those last 6 beats :)
current.update (current.position - (midi_clock_count % 6) * one_ppqn_in_samples, 0, 0);
}
}
void
MIDIClock_TransportMaster::position (Parser& /*parser*/, MIDI::byte* message, size_t size, samplepos_t timestamp)
{
// we are not supposed to get position messages while we are running
// so lets be robust and ignore those
if (_running) {
return;
}
assert(size == 3);
MIDI::byte lsb = message[1];
MIDI::byte msb = message[2];
assert((lsb <= 0x7f) && (msb <= 0x7f));
uint16_t position_in_sixteenth_notes = (uint16_t(msb) << 7) | uint16_t(lsb);
samplepos_t position_in_samples = calculate_song_position(position_in_sixteenth_notes);
DEBUG_TRACE (DEBUG::MidiClock, string_compose ("Song Position: %1 samples: %2\n", position_in_sixteenth_notes, position_in_samples));
current.update (position_in_samples + midi_port_latency.max, timestamp, current.speed);
}
bool
MIDIClock_TransportMaster::locked () const
{
return true;
}
bool
MIDIClock_TransportMaster::ok() const
{
return true;
}
ARDOUR::samplecnt_t
MIDIClock_TransportMaster::update_interval() const
{
if (one_ppqn_in_samples) {
return resolution ();
}
return AudioEngine::instance()->sample_rate() / 120 / 4; /* pure guesswork */
}
ARDOUR::samplecnt_t
MIDIClock_TransportMaster::resolution() const
{
// one beat
return (samplecnt_t) one_ppqn_in_samples * ppqn;
}
std::string
MIDIClock_TransportMaster::position_string () const
{
return std::string();
}
std::string
MIDIClock_TransportMaster::delta_string() const
{
SafeTime last;
current.safe_read (last);
if (last.timestamp == 0 || starting()) {
return X_("\u2012\u2012\u2012\u2012");
} else {
return format_delta_time (_current_delta);
}
}
void
MIDIClock_TransportMaster::unregister_port ()
{
_midi_port.reset ();
TransportMaster::unregister_port ();
}