transport_master.h

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/*
 * Copyright (C) 2018-2019 Paul Davis <paul@linuxaudiosystems.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.
 */
 
#pragma once
 
#include <vector>
 
#include <optional>
 
#include <glibmm/timer.h>
 
#include <ltc.h>
 
#include "pbd/properties.h"
#include "pbd/mutex.h"
#include "pbd/signals.h"
#include "pbd/statefuldestructible.h"
 
#include "temporal/time.h"
 
#include "ardour/libardour_visibility.h"
#include "ardour/region.h" /* for Properties::locked */
#include "ardour/types.h"
 
#include "midi++/parser.h"
#include "midi++/types.h"
 
namespace ARDOUR {
 
class Session;
class AudioEngine;
class Location;
class MidiPort;
class AudioPort;
class Port;
 
namespace Properties {
        LIBARDOUR_API extern PBD::PropertyDescriptor<bool>                         fr2997;
        LIBARDOUR_API extern PBD::PropertyDescriptor<bool>                         collect;
        LIBARDOUR_API extern PBD::PropertyDescriptor<bool>                         connected;
        LIBARDOUR_API extern PBD::PropertyDescriptor<bool>                         sclock_synced;
        LIBARDOUR_API extern PBD::PropertyDescriptor<ARDOUR::TransportRequestType> allowed_transport_requests;
}
 
struct LIBARDOUR_API SafeTime {
        /* This object uses memory fences to provide psuedo-atomic updating of
         * non-atomic data. If after reading guard1 and guard2 with correct
         * memory fencing they have the same value, then we know that the other
         * members are all internally consistent.
         *
         * Traditionally, one might do this with a mutex, but this object
         * provides lock-free write update. The reader might block while
         * waiting for consistency, but this is extraordinarily unlikely. In
         * this sense, the design is similar to a spinlock.
         *
         * any update starts by incrementing guard1, with a memory fence to
         * ensure no reordering of this w.r.t later operations.
         *
         * then we update the "non-atomic" data members.
         *
         * then we update guard2, with another memory fence to prevent
         * reordering.
         *
         * ergo, if guard1 == guard2, the update of the non-atomic members is
         * complete and the values stored there are consistent.
         */
 
        std::atomic<int> guard1;
        samplepos_t      position;
        samplepos_t      timestamp;
        double           speed;
        std::atomic<int> guard2;
 
        SafeTime ()
        {
                guard1.store (0);
                position  = 0;
                timestamp = 0;
                speed     = 0;
                guard2.store (0);
        }
 
        void reset ()
        {
                guard1.store (0);
                position  = 0;
                timestamp = 0;
                speed     = 0;
                guard2.store (0);
        }
 
        void update (samplepos_t p, samplepos_t t, double s)
        {
                guard1.fetch_add (1, std::memory_order_acquire);
                position  = p;
                timestamp = t;
                speed     = s;
                guard2.fetch_add (1, std::memory_order_acquire);
        }
 
        void safe_read (SafeTime& dst) const
        {
                int tries = 0;
 
                do {
                        if (tries == 10) {
                                std::cerr << "SafeTime: atomic read of current time failed, sleeping!" << std::endl;
                                Glib::usleep (20);
                                tries = 0;
                        }
                        dst.guard1.store (guard1.load (std::memory_order_seq_cst), std::memory_order_seq_cst);
                        dst.position  = position;
                        dst.timestamp = timestamp;
                        dst.speed     = speed;
                        dst.guard2.store (guard2.load (std::memory_order_seq_cst), std::memory_order_seq_cst);
                        tries++;
 
                } while (dst.guard1.load (std::memory_order_seq_cst) != dst.guard2.load (std::memory_order_seq_cst));
        }
};
 
class LIBARDOUR_API TransportMaster : public PBD::Stateful
{
public:
        TransportMaster (SyncSource t, std::string const& name);
        virtual ~TransportMaster ();
 
        static std::shared_ptr<TransportMaster> factory (SyncSource, std::string const&, bool removeable);
        static std::shared_ptr<TransportMaster> factory (XMLNode const&);
 
        virtual void pre_process (pframes_t nframes, samplepos_t now, std::optional<samplepos_t>) = 0;
 
        virtual bool speed_and_position (double& speed, samplepos_t& position, samplepos_t& lp, samplepos_t& when, samplepos_t now);
 
        virtual void reset (bool with_position) = 0;
 
        virtual bool locked () const = 0;
 
        virtual bool ok () const = 0;
 
        virtual bool usable () const
        {
                return true;
        }
 
        virtual bool starting () const
        {
                return false;
        }
 
        virtual samplecnt_t resolution () const = 0;
 
        virtual samplecnt_t update_interval () const = 0;
 
        virtual bool requires_seekahead () const = 0;
 
        virtual samplecnt_t seekahead_distance () const
        {
                return 0;
        }
 
        virtual bool sample_clock_synced () const
        {
                return _sclock_synced;
        }
        virtual void set_sample_clock_synced (bool);
 
        virtual std::string delta_string () const
        {
                return "";
        }
 
        sampleoffset_t current_delta () const
        {
                return _current_delta;
        }
 
        /* this is intended to be used by a UI and polled from a timeout. it should
           return a string describing the current position of the TC source. it
           should NOT do any computation, but should use a cached value
           of the TC source position.
        */
        virtual std::string position_string () const = 0;
 
        /* This can be used as display value when transport is not locked,
         * but a valid position has been received. e.g LTC standing TC.
         */
        virtual bool valid_position (std::string& tc, samplepos_t& pos, samplepos_t& when) const
        {
                return false;
        }
 
        virtual bool can_loop () const
        {
                return false;
        }
 
        virtual Location* loop_location () const
        {
                return 0;
        }
        bool has_loop () const
        {
                return loop_location () != 0;
        }
 
        SyncSource type () const
        {
                return _type;
        }
        TransportRequestSource request_type () const
        {
                switch (_type) {
                        case Engine: /* also JACK */
                                return TRS_Engine;
                        case MTC:
                                return TRS_MTC;
                        case LTC:
                                return TRS_LTC;
                        case WallClock:
                                return TRS_WallClock;
                        case MIDIClock:
                                break;
                }
                return TRS_MIDIClock;
        }
 
        std::string name () const
        {
                return _name;
        }
        void set_name (std::string const&);
 
        int      set_state (XMLNode const&, int);
        XMLNode& get_state () const;
 
        static const std::string state_node_name;
        static void              make_property_quarks ();
 
        virtual void set_session (Session*);
 
        std::shared_ptr<Port> port () const
        {
                return _port;
        }
 
        bool         check_collect ();
        virtual void set_collect (bool);
        bool         collect () const
        {
                return _collect;
        }
 
        /* called whenever the manager starts collecting (processing) this
           transport master. Typically will re-initialize any state used to
           deal with incoming data.
        */
        virtual void init () = 0;
 
        virtual void check_backend () {}
        virtual bool allow_request (TransportRequestSource, TransportRequestType) const;
        std::string  allowed_request_string () const;
 
        TransportRequestType request_mask () const
        {
                return _request_mask;
        }
        void set_request_mask (TransportRequestType);
 
        /* this is set at construction, and not changeable later, so it is not
         * a property
         */
 
        bool removeable () const
        {
                return _removeable;
        }
        void set_removeable (bool yn)
        {
                _removeable = yn;
        }
 
        std::string display_name (bool sh /*ort*/ = true) const;
 
        virtual void unregister_port ();
        void         connect_port_using_state ();
        virtual void create_port () = 0;
 
protected:
        SyncSource                          _type;
        PBD::Property<std::string>          _name;
        Session*                            _session;
        sampleoffset_t                      _current_delta;
        bool                                _pending_collect;
        bool                                _removeable;
        PBD::Property<TransportRequestType> _request_mask; /* lists transport requests still accepted when we're in control */
        PBD::Property<bool>                 _sclock_synced;
        PBD::Property<bool>                 _collect;
        PBD::Property<bool>                 _connected;
 
        SafeTime current;
 
        /* DLL - chase incoming data */
 
        int transport_direction;
        int dll_initstate;
 
        double t0;
        double t1;
        double e2;
        double b, c;
 
        std::shared_ptr<Port> _port;
 
        mutable XMLNode port_node;
 
        virtual void connection_handler (std::weak_ptr<ARDOUR::Port>, std::string name1, std::weak_ptr<ARDOUR::Port>, std::string name2, bool yn);
 
        PBD::ScopedConnection port_connection;
        PBD::ScopedConnection backend_connection;
 
        virtual void register_properties ();
 
        virtual std::string format_delta_time (sampleoffset_t) const;
};
 
class LIBARDOUR_API TransportMasterViaMIDI
{
public:
        virtual ~TransportMasterViaMIDI ();
 
        MIDI::Parser& transport_parser () { return parser; }
        std::shared_ptr<MidiPort> midi_port () const
        {
                return _midi_port;
        }
        std::shared_ptr<Port> create_midi_port (std::string const& port_name);
 
        virtual void set_session (Session*);
 
protected:
        TransportMasterViaMIDI () {};
 
        void resync_latency (bool);
        MIDI::Parser                parser;
        std::shared_ptr<MidiPort> _midi_port;
 
        virtual void parameter_changed (std::string const& p) {}
 
        LatencyRange midi_port_latency;
 
private:
        PBD::ScopedConnectionList session_connections;
};
 
class LIBARDOUR_API TimecodeTransportMaster : public TransportMaster
{
public:
        TimecodeTransportMaster (std::string const& name, SyncSource type);
 
        virtual Timecode::TimecodeFormat apparent_timecode_format () const = 0;
 
        bool apparent_timecode_format_valid () const {
                return timecode_format_valid;
        }
 
        bool fr2997 () const
        {
                return _fr2997;
        }
        void set_fr2997 (bool);
 
protected:
        void register_properties ();
 
        samplepos_t timecode_offset;
        bool        timecode_negative_offset;
        bool        timecode_format_valid;
 
private:
        PBD::Property<bool> _fr2997;
};
 
class LIBARDOUR_API MTC_TransportMaster : public TimecodeTransportMaster, public TransportMasterViaMIDI
{
public:
        MTC_TransportMaster (std::string const&);
        ~MTC_TransportMaster ();
 
        void set_session (Session*);
 
        void pre_process (pframes_t nframes, samplepos_t now, std::optional<samplepos_t>);
 
        void unregister_port ();
 
        void reset (bool with_pos);
        bool locked () const;
        bool ok () const;
        void handle_locate (const MIDI::byte*);
 
        samplecnt_t update_interval () const;
        samplecnt_t resolution () const;
        bool        requires_seekahead () const
        {
                return false;
        }
        samplecnt_t seekahead_distance () const;
        void        init ();
 
        Timecode::TimecodeFormat apparent_timecode_format () const;
        std::string              position_string () const;
        std::string              delta_string () const;
 
        void create_port ();
 
private:
        PBD::ScopedConnectionList port_connections;
        bool                      can_notify_on_unknown_rate;
 
        static const int sample_tolerance;
 
        samplepos_t              mtc_frame; /* current time */
        double                   mtc_frame_dll;
        samplepos_t              last_inbound_frame; /* when we got it; audio clocked */
        MIDI::byte               last_mtc_fps_byte;
        samplepos_t              window_begin;
        samplepos_t              window_end;
        samplepos_t              first_mtc_timestamp;
 
        PBD::Mutex     reset_lock;
        uint32_t                 reset_pending;
        bool                     reset_position;
        int                      transport_direction;
        int                      busy_guard1;
        int                      busy_guard2;
 
        double                   quarter_frame_duration;
        Timecode::TimecodeFormat mtc_timecode;
        Timecode::Time           timecode;
 
        void queue_reset (bool with_pos);
        void maybe_reset ();
 
        void update_mtc_qtr (MIDI::Parser&, int, samplepos_t);
        void update_mtc_time (const MIDI::byte*, bool, samplepos_t);
        void update_mtc_status (MIDI::MTC_Status);
        void reset_window (samplepos_t);
        bool outside_window (samplepos_t) const;
        void init_mtc_dll (samplepos_t, double);
        void parse_timecode_offset ();
        void parameter_changed (std::string const& p);
 
        void connection_handler (std::weak_ptr<ARDOUR::Port>, std::string, std::weak_ptr<ARDOUR::Port>, std::string, bool);
};
 
class LIBARDOUR_API LTC_TransportMaster : public TimecodeTransportMaster
{
public:
        LTC_TransportMaster (std::string const&);
        ~LTC_TransportMaster ();
 
        void set_session (Session*);
 
        void pre_process (pframes_t nframes, samplepos_t now, std::optional<samplepos_t>);
 
        void reset (bool with_pos);
        bool locked () const;
        bool ok () const;
 
        samplecnt_t update_interval () const;
        samplecnt_t resolution () const;
        bool        requires_seekahead () const
        {
                return false;
        }
        samplecnt_t seekahead_distance () const
        {
                return 0;
        }
        void init ();
        void set_sample_clock_synced (bool);
 
        Timecode::TimecodeFormat apparent_timecode_format () const;
        std::string              position_string () const;
        std::string              delta_string () const;
 
        bool valid_position (std::string& tc, samplepos_t& pos, samplepos_t& when) const;
 
        void create_port ();
 
private:
        void parse_ltc (const pframes_t, Sample const*, samplecnt_t);
        void process_ltc (samplepos_t const);
        void init_dll (samplepos_t, int32_t);
        bool detect_discontinuity (LTCFrameExt*, int, bool);
        bool detect_ltc_fps (int, bool);
        bool equal_ltc_sample_time (LTCFrame* a, LTCFrame* b);
        void resync_xrun ();
        void resync_latency (bool);
        void parse_timecode_offset ();
        void parameter_changed (std::string const& p);
        void connection_handler (std::weak_ptr<ARDOUR::Port>, std::string, std::weak_ptr<ARDOUR::Port>, std::string, bool);
 
        LTCDecoder*    decoder;
        double         samples_per_ltc_frame;
        Timecode::Time timecode;
        LTCFrameExt    prev_frame;
        bool           fps_detected;
 
        samplecnt_t    monotonic_cnt;
        uint64_t       frames_since_reset;
        int            delayedlocked;
 
        samplepos_t    frame_age;
 
        int            ltc_detect_fps_cnt;
        int            ltc_detect_fps_max;
        bool           sync_lock_broken;
        double         samples_per_timecode_frame;
 
        PBD::ScopedConnection     port_connection;
        PBD::ScopedConnectionList session_connections;
        LatencyRange              ltc_slave_latency;
 
 
        struct Biquad {
                void reset () { z1 = z2 = 0;}
                float  z1, z2;
                double a1, a2, b0, b1, b2;
        };
 
        bool   _filter_enable;
        Biquad _lpf;
        Biquad _hpf;
};
 
class LIBARDOUR_API WallClock_TransportMaster : public TimecodeTransportMaster
{
public:
        WallClock_TransportMaster (std::string const&);
        ~WallClock_TransportMaster ();
 
        void set_session (Session*);
 
        void pre_process (pframes_t nframes, samplepos_t now, std::optional<samplepos_t>);
 
        void reset (bool with_pos);
        bool locked () const { return true; }
        bool ok () const { return true; }
 
        samplecnt_t update_interval () const;
        samplecnt_t resolution () const;
        bool        requires_seekahead () const { return false; }
        void        init ();
 
        Timecode::TimecodeFormat apparent_timecode_format () const;
        std::string              position_string () const;
 
        void create_port () {}
        void check_backend ();
 
private:
        samplepos_t _time;
        bool        _set;
};
 
class LIBARDOUR_API MIDIClock_TransportMaster : public TransportMaster, public TransportMasterViaMIDI
{
public:
        MIDIClock_TransportMaster (std::string const& name, int ppqn = 24);
 
        ~MIDIClock_TransportMaster ();
 
        void set_session (Session*);
 
        void unregister_port ();
 
        void pre_process (pframes_t nframes, samplepos_t now, std::optional<samplepos_t>);
 
        void rebind (MidiPort&);
 
        void reset (bool with_pos);
        bool locked () const;
        bool ok () const;
 
        samplecnt_t update_interval () const;
        samplecnt_t resolution () const;
        bool        requires_seekahead () const
        {
                return false;
        }
        void init ();
 
        std::string position_string () const;
        std::string delta_string () const;
 
        float bpm () const
        {
                return _bpm;
        }
 
        void create_port ();
 
protected:
        PBD::ScopedConnectionList port_connections;
 
        int ppqn;
 
        double one_ppqn_in_samples;
 
        samplepos_t first_timestamp;
 
        samplepos_t last_timestamp;
        double      should_be_position;
 
        long midi_clock_count;
 
 
        double _speed;
        bool   _running;
        double _bpm;
 
        void start (MIDI::Parser& parser, samplepos_t timestamp);
        void contineu (MIDI::Parser& parser, samplepos_t timestamp); // we can't use continue because it is a C++ keyword
        void stop (MIDI::Parser& parser, samplepos_t timestamp);
        void position (MIDI::Parser& parser, MIDI::byte* message, size_t size, samplepos_t timestamp);
 
        void        calculate_one_ppqn_in_samples_at (samplepos_t time);
        samplepos_t calculate_song_position (uint16_t song_position_in_sixteenth_notes);
        void        calculate_filter_coefficients (double qpm);
        void        update_midi_clock (MIDI::Parser& parser, samplepos_t timestamp);
 
        void connection_handler (std::weak_ptr<ARDOUR::Port>, std::string, std::weak_ptr<ARDOUR::Port>, std::string, bool);
};
 
class LIBARDOUR_API Engine_TransportMaster : public TransportMaster
{
public:
        Engine_TransportMaster (AudioEngine&);
        ~Engine_TransportMaster ();
 
        void pre_process (pframes_t nframes, samplepos_t now, std::optional<samplepos_t>);
        bool speed_and_position (double& speed, samplepos_t& pos, samplepos_t&, samplepos_t&, samplepos_t);
 
        bool starting () const
        {
                return _starting;
        }
        void        reset (bool with_position);
        bool        locked () const;
        bool        ok () const;
        bool        usable () const;
        samplecnt_t update_interval () const;
        samplecnt_t resolution () const
        {
                return 1;
        }
        bool requires_seekahead () const
        {
                return false;
        }
        bool sample_clock_synced () const
        {
                return true;
        }
        void init ();
        void check_backend ();
        bool allow_request (TransportRequestSource, TransportRequestType) const;
 
        std::string position_string () const;
        std::string delta_string () const;
 
        void create_port () {}
 
private:
        AudioEngine& engine;
        bool         _starting;
};
 
}