diff options
Diffstat (limited to 'libs/ardour/mtc_slave.cc')
| -rw-r--r-- | libs/ardour/mtc_slave.cc | 111 |
1 files changed, 89 insertions, 22 deletions
diff --git a/libs/ardour/mtc_slave.cc b/libs/ardour/mtc_slave.cc index 9e566367bc..41aaaccbcf 100644 --- a/libs/ardour/mtc_slave.cc +++ b/libs/ardour/mtc_slave.cc @@ -41,6 +41,16 @@ using namespace sigc; using namespace MIDI; using namespace PBD; +/* length (in timecode frames) of the "window" that we consider legal given receipt of + a given timecode position. Ardour will try to chase within this window, and will + stop+locate+wait+chase if timecode arrives outside of it. The window extends entirely + in the current direction of motion, so if any timecode arrives that is before the most + recently received position (and without the direction of timecode reversing too), we + will stop+locate+wait+chase. +*/ + +const int MTC_Slave::frame_tolerance = 2; + MTC_Slave::MTC_Slave (Session& s, MIDI::Port& p) : session (s) { @@ -71,8 +81,8 @@ MTC_Slave::~MTC_Slave() bool MTC_Slave::give_slave_full_control_over_transport_speed() const { - return true; // for PiC control */ - // return false; // for Session-level computed varispeed + // return true; // for PiC control */ + return false; // for Session-level computed varispeed } void @@ -84,8 +94,6 @@ MTC_Slave::rebind (MIDI::Port& p) port = &p; - cerr << "Bind to port MTC messages\n"; - connections.push_back (port->input()->mtc_time.connect (mem_fun (*this, &MTC_Slave::update_mtc_time))); connections.push_back (port->input()->mtc_qtr.connect (mem_fun (*this, &MTC_Slave::update_mtc_qtr))); connections.push_back (port->input()->mtc_status.connect (mem_fun (*this, &MTC_Slave::update_mtc_status))); @@ -94,6 +102,8 @@ MTC_Slave::rebind (MIDI::Port& p) void MTC_Slave::update_mtc_qtr (Parser& /*p*/, int which_qtr, nframes_t now) { + maybe_reset (); + DEBUG_TRACE (DEBUG::MTC, string_compose ("qtr frame %1 at %2\n", which_qtr, now)); last_inbound_frame = now; } @@ -102,9 +112,14 @@ void MTC_Slave::update_mtc_time (const byte *msg, bool was_full, nframes_t now) { /* "now" can be zero if this is called from a context where we do not have or do not want - to use a timestamp indicating when this MTC time was received. + to use a timestamp indicating when this MTC time was received. example: when we received + a locate command via MMC. */ + if (now) { + maybe_reset (); + } + Timecode::Time timecode; TimecodeFormat tc_format; bool reset_tc = true; @@ -174,8 +189,7 @@ MTC_Slave::update_mtc_time (const byte *msg, bool was_full, nframes_t now) session.request_locate (mtc_frame, false); session.request_transport_speed (0); update_mtc_status (MIDI::MTC_Stopped); - window_root = mtc_frame; - + reset_window (mtc_frame); reset (); } else { @@ -265,6 +279,12 @@ MTC_Slave::process_apparent_speed (double this_speed) { DEBUG_TRACE (DEBUG::MTC, string_compose ("speed cnt %1 sz %2 have %3\n", speed_accumulator_cnt, speed_accumulator_size, have_first_speed_accumulator)); + /* clamp to an expected range */ + + if (this_speed > 4.0 || this_speed < -4.0) { + this_speed = average_speed; + } + if (speed_accumulator_cnt >= speed_accumulator_size) { have_first_speed_accumulator = true; speed_accumulator_cnt = 0; @@ -385,9 +405,8 @@ MTC_Slave::speed_and_position (double& speed, nframes64_t& pos) pos = last.position; session.request_locate (pos, false); session.request_transport_speed (0); - update_mtc_status (MIDI::MTC_Stopped); - reset(); - DEBUG_TRACE (DEBUG::MTC, "MTC not seen for 1/4 second - reset\n"); + queue_reset (); + DEBUG_TRACE (DEBUG::MTC, "MTC not seen for 1/4 second - reset pending\n"); return false; } @@ -427,13 +446,28 @@ MTC_Slave::resolution() const } void -MTC_Slave::reset () +MTC_Slave::queue_reset () { - /* XXX massive thread safety issue here. MTC could - be being updated as we call this. but this - supposed to be a realtime-safe call. - */ + Glib::Mutex::Lock lm (reset_lock); + reset_pending++; +} + +void +MTC_Slave::maybe_reset () +{ + reset_lock.lock (); + + if (reset_pending) { + reset (); + reset_pending = 0; + } + + reset_lock.unlock (); +} +void +MTC_Slave::reset () +{ port->input()->reset_mtc_state (); last_inbound_frame = 0; @@ -458,15 +492,48 @@ MTC_Slave::reset () void MTC_Slave::reset_window (nframes64_t root) { - window_begin = root; + + /* if we're waiting for the master to catch us after seeking ahead, keep the window + of acceptable MTC frames wide open. otherwise, shrink it down to just 2 video frames + ahead of the window root (taking direction into account). + */ - if (session.slave_state() == Session::Running) { - window_end = root + (session.frames_per_timecode_frame() * 2); - } else { - window_end = root + seekahead_distance (); - } + switch (port->input()->mtc_running()) { + case MTC_Forward: + window_begin = root; + if (session.slave_state() == Session::Running) { + window_end = root + (session.frames_per_timecode_frame() * frame_tolerance); + } else { + window_end = root + seekahead_distance (); + } + DEBUG_TRACE (DEBUG::MTC, string_compose ("legal MTC window now %1 .. %2\n", window_begin, window_end)); + break; - DEBUG_TRACE (DEBUG::MTC, string_compose ("legal MTC window now %1 .. %2\n", window_begin, window_end)); + case MTC_Backward: + if (session.slave_state() == Session::Running) { + nframes_t d = session.frames_per_timecode_frame() * frame_tolerance; + if (root > d) { + window_begin = root - d; + window_end = root; + } else { + window_begin = 0; + } + } else { + nframes_t d = seekahead_distance (); + if (root > d) { + window_begin = root - d; + } else { + window_begin = 0; + } + } + window_end = root; + DEBUG_TRACE (DEBUG::MTC, string_compose ("legal MTC window now %1 .. %2\n", window_begin, window_end)); + break; + + default: + /* do nothing */ + break; + } } nframes64_t |