libs/ardour/ltc_slave.cc

   1 /*
   2     Copyright (C) 2012 Paul Davis
   3     Witten by 2012 Robin Gareus <robin@gareus.org>
   4
   5     This program is free software; you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation; either version 2 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License
  16     along with this program; if not, write to the Free Software
  17     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18
  19 */
  20 #include <iostream>
  21 #include <errno.h>
  22 #include <sys/types.h>
  23 #include <unistd.h>
  24
  25 #include "pbd/error.h"
  26 #include "pbd/pthread_utils.h"
  27
  28 #include "ardour/debug.h"
  29 #include "ardour/profile.h"
  30 #include "ardour/slave.h"
  31 #include "ardour/session.h"
  32 #include "ardour/audioengine.h"
  33 #include "ardour/audio_port.h"
  34
  35 #include "pbd/i18n.h"
  36
  37 using namespace std;
  38 using namespace ARDOUR;
  39 using namespace MIDI;
  40 using namespace PBD;
  41 using namespace Timecode;
  42
  43 #define FLYWHEEL_TIMEOUT ( 1 * session.frame_rate() )
  44
  45 LTC_Slave::LTC_Slave (Session& s)
  46         : session (s)
  47 {
  48         frames_per_ltc_frame = session.frames_per_timecode_frame();
  49         timecode.rate = session.timecode_frames_per_second();
  50         timecode.drop  = session.timecode_drop_frames();
  51
  52         did_reset_tc_format = false;
  53         delayedlocked = 10;
  54         monotonic_cnt = 0;
  55         fps_detected=false;
  56         sync_lock_broken = false;
  57
  58         ltc_timecode = session.config.get_timecode_format();
  59         a3e_timecode = session.config.get_timecode_format();
  60         printed_timecode_warning = false;
  61         ltc_detect_fps_cnt = ltc_detect_fps_max = 0;
  62         memset(&prev_frame, 0, sizeof(LTCFrameExt));
  63
  64         decoder = ltc_decoder_create((int) frames_per_ltc_frame, 128 /*queue size*/);
  65
  66         session.config.ParameterChanged.connect_same_thread (config_connection, boost::bind (&LTC_Slave::parameter_changed, this, _1));
  67         parse_timecode_offset();
  68         reset();
  69         resync_latency();
  70         session.Xrun.connect_same_thread (port_connections, boost::bind (&LTC_Slave::resync_xrun, this));
  71         session.engine().GraphReordered.connect_same_thread (port_connections, boost::bind (&LTC_Slave::resync_latency, this));
  72 }
  73
  74 LTC_Slave::~LTC_Slave()
  75 {
  76         port_connections.drop_connections();
  77         config_connection.disconnect();
  78
  79         if (did_reset_tc_format) {
  80                 session.config.set_timecode_format (saved_tc_format);
  81         }
  82
  83         ltc_decoder_free(decoder);
  84 }
  85
  86 void
  87 LTC_Slave::parse_timecode_offset() {
  88         Timecode::Time offset_tc;
  89         Timecode::parse_timecode_format(session.config.get_slave_timecode_offset(), offset_tc);
  90         offset_tc.rate = session.timecode_frames_per_second();
  91         offset_tc.drop = session.timecode_drop_frames();
  92         session.timecode_to_sample(offset_tc, timecode_offset, false, false);
  93         timecode_negative_offset = offset_tc.negative;
  94 }
  95
  96 void
  97 LTC_Slave::parameter_changed (std::string const & p)
  98 {
  99         if (p == "slave-timecode-offset"
 100                         || p == "timecode-format"
 101                         ) {
 102                 parse_timecode_offset();
 103         }
 104 }
 105
 106 ARDOUR::framecnt_t
 107 LTC_Slave::resolution () const
 108 {
 109         return (framecnt_t) (session.frame_rate() / 1000);
 110 }
 111
 112 bool
 113 LTC_Slave::locked () const
 114 {
 115         return (delayedlocked < 5);
 116 }
 117
 118 bool
 119 LTC_Slave::ok() const
 120 {
 121         return true;
 122 }
 123
 124 void
 125 LTC_Slave::resync_xrun()
 126 {
 127         DEBUG_TRACE (DEBUG::LTC, "LTC resync_xrun()\n");
 128         engine_dll_initstate = 0;
 129         sync_lock_broken = false;
 130 }
 131
 132 void
 133 LTC_Slave::resync_latency()
 134 {
 135         DEBUG_TRACE (DEBUG::LTC, "LTC resync_latency()\n");
 136         engine_dll_initstate = 0;
 137         sync_lock_broken = false;
 138
 139         if (!session.deletion_in_progress() && session.ltc_output_io()) { /* check if Port exits */
 140                 boost::shared_ptr<Port> ltcport = session.ltc_input_port();
 141                 ltcport->get_connected_latency_range (ltc_slave_latency, false);
 142         }
 143 }
 144
 145 void
 146 LTC_Slave::reset()
 147 {
 148         DEBUG_TRACE (DEBUG::LTC, "LTC reset()\n");
 149         last_timestamp = 0;
 150         current_delta = 0;
 151         transport_direction = 0;
 152         ltc_speed = 0;
 153         engine_dll_initstate = 0;
 154         sync_lock_broken = false;
 155
 156         ActiveChanged (false); /* EMIT SIGNAL */
 157 }
 158
 159 void
 160 LTC_Slave::parse_ltc(const ARDOUR::pframes_t nframes, const Sample* const in, const ARDOUR::framecnt_t posinfo)
 161 {
 162         pframes_t i;
 163         unsigned char sound[8192];
 164         if (nframes > 8192) {
 165                 /* TODO warn once or wrap, loop conversion below
 166                  * does jack/A3 support > 8192 spp anyway?
 167                  */
 168                 return;
 169         }
 170
 171         for (i = 0; i < nframes; i++) {
 172                 const int snd=(int)rint((127.0*in[i])+128.0);
 173                 sound[i] = (unsigned char) (snd&0xff);
 174         }
 175         ltc_decoder_write(decoder, sound, nframes, posinfo);
 176         return;
 177 }
 178
 179 bool
 180 LTC_Slave::equal_ltc_frame_time(LTCFrame *a, LTCFrame *b) {
 181         if (       a->frame_units != b->frame_units
 182                 || a->frame_tens  != b->frame_tens
 183                 || a->dfbit       != b->dfbit
 184                 || a->secs_units  != b->secs_units
 185                 || a->secs_tens   != b->secs_tens
 186                 || a->mins_units  != b->mins_units
 187                 || a->mins_tens   != b->mins_tens
 188                 || a->hours_units != b->hours_units
 189                 || a->hours_tens  != b->hours_tens
 190              ) {
 191                 return false;
 192         }
 193         return true;
 194 }
 195
 196 bool
 197 LTC_Slave::detect_discontinuity(LTCFrameExt *frame, int fps, bool fuzzy) {
 198         bool discontinuity_detected = false;
 199
 200         if (fuzzy && (
 201                   ( frame->reverse && prev_frame.ltc.frame_units == 0)
 202                 ||(!frame->reverse && frame->ltc.frame_units == 0)
 203                 )) {
 204                 memcpy(&prev_frame, frame, sizeof(LTCFrameExt));
 205                 return false;
 206         }
 207
 208         if (frame->reverse) {
 209                 ltc_frame_decrement(&prev_frame.ltc, fps, LTC_TV_525_60, 0);
 210         } else {
 211                 ltc_frame_increment(&prev_frame.ltc, fps, LTC_TV_525_60, 0);
 212         }
 213         if (!equal_ltc_frame_time(&prev_frame.ltc, &frame->ltc)) {
 214                 discontinuity_detected = true;
 215         }
 216
 217     memcpy(&prev_frame, frame, sizeof(LTCFrameExt));
 218     return discontinuity_detected;
 219 }
 220
 221 bool
 222 LTC_Slave::detect_ltc_fps(int frameno, bool df)
 223 {
 224         bool fps_changed = false;
 225         double detected_fps = 0;
 226         if (frameno > ltc_detect_fps_max)
 227         {
 228                 ltc_detect_fps_max = frameno;
 229         }
 230         ltc_detect_fps_cnt++;
 231
 232         if (ltc_detect_fps_cnt > 40) {
 233                 if (ltc_detect_fps_cnt > ltc_detect_fps_max) {
 234                         detected_fps = ltc_detect_fps_max + 1;
 235                         if (df) {
 236                                 /* LTC df -> indicates fractional framerate */
 237                                 if (Config->get_timecode_source_2997()) {
 238                                         detected_fps = detected_fps * 999.0 / 1000.0;
 239                                 } else {
 240                                         detected_fps = detected_fps * 1000.0 / 1001.0;
 241                                 }
 242                         }
 243
 244                         if (timecode.rate != detected_fps || timecode.drop != df) {
 245                                 DEBUG_TRACE (DEBUG::LTC, string_compose ("LTC detected FPS: %1%2\n", detected_fps, df?"df":"ndf"));
 246                         } else {
 247                                 detected_fps = 0; /* no cange */
 248                         }
 249                 }
 250                 ltc_detect_fps_cnt = ltc_detect_fps_max = 0;
 251         }
 252
 253         /* when changed */
 254         if (detected_fps != 0 && (detected_fps != timecode.rate || df != timecode.drop)) {
 255                 timecode.rate = detected_fps;
 256                 timecode.drop = df;
 257                 frames_per_ltc_frame = double(session.frame_rate()) / timecode.rate;
 258                 DEBUG_TRACE (DEBUG::LTC, string_compose ("LTC reset to FPS: %1%2 ; audio-frames per LTC: %3\n",
 259                                 detected_fps, df?"df":"ndf", frames_per_ltc_frame));
 260                 fps_changed=true;
 261         }
 262
 263         /* poll and check session TC */
 264         TimecodeFormat tc_format = apparent_timecode_format();
 265         TimecodeFormat cur_timecode = session.config.get_timecode_format();
 266
 267         if (Config->get_timecode_sync_frame_rate()) {
 268                 /* enforce time-code */
 269                 if (!did_reset_tc_format) {
 270                         saved_tc_format = cur_timecode;
 271                         did_reset_tc_format = true;
 272                 }
 273                 if (cur_timecode != tc_format) {
 274                         if (ceil(Timecode::timecode_to_frames_per_second(cur_timecode)) != ceil(Timecode::timecode_to_frames_per_second(tc_format))) {
 275                                 warning << string_compose(_("Session framerate adjusted from %1 to LTC's %2."),
 276                                                 Timecode::timecode_format_name(cur_timecode),
 277                                                 Timecode::timecode_format_name(tc_format))
 278                                         << endmsg;
 279                         }
 280                         session.config.set_timecode_format (tc_format);
 281                 }
 282         } else {
 283                 /* only warn about TC mismatch */
 284                 if (ltc_timecode != tc_format) printed_timecode_warning = false;
 285                 if (a3e_timecode != cur_timecode) printed_timecode_warning = false;
 286
 287                 if (cur_timecode != tc_format && ! printed_timecode_warning) {
 288                         if (ceil(Timecode::timecode_to_frames_per_second(cur_timecode)) != ceil(Timecode::timecode_to_frames_per_second(tc_format))) {
 289                                 warning << string_compose(_("Session and LTC framerate mismatch: LTC:%1 Session:%2."),
 290                                                 Timecode::timecode_format_name(tc_format),
 291                                                 Timecode::timecode_format_name(cur_timecode))
 292                                         << endmsg;
 293                         }
 294                         printed_timecode_warning = true;
 295                 }
 296         }
 297         ltc_timecode = tc_format;
 298         a3e_timecode = cur_timecode;
 299
 300         return fps_changed;
 301 }
 302
 303 void
 304 LTC_Slave::process_ltc(framepos_t const /*now*/)
 305 {
 306         LTCFrameExt frame;
 307         enum LTC_TV_STANDARD tv_standard = LTC_TV_625_50;
 308         while (ltc_decoder_read(decoder, &frame)) {
 309                 SMPTETimecode stime;
 310
 311                 ltc_frame_to_time(&stime, &frame.ltc, 0);
 312                 timecode.negative  = false;
 313                 timecode.subframes  = 0;
 314
 315                 /* set timecode.rate and timecode.drop: */
 316                 bool ltc_is_static = equal_ltc_frame_time(&prev_frame.ltc, &frame.ltc);
 317
 318                 if (detect_discontinuity(&frame, ceil(timecode.rate), !fps_detected)) {
 319                         if (fps_detected) { ltc_detect_fps_cnt = ltc_detect_fps_max = 0; }
 320                         fps_detected=false;
 321                 }
 322
 323                 if (!ltc_is_static && detect_ltc_fps(stime.frame, (frame.ltc.dfbit)? true : false)) {
 324                         reset();
 325                         fps_detected=true;
 326                 }
 327
 328 #if 0 // Devel/Debug
 329                 fprintf(stdout, "LTC %02d:%02d:%02d%c%02d | %8lld %8lld%s\n",
 330                         stime.hours,
 331                         stime.mins,
 332                         stime.secs,
 333                         (frame.ltc.dfbit) ? '.' : ':',
 334                         stime.frame,
 335                         frame.off_start,
 336                         frame.off_end,
 337                         frame.reverse ? " R" : "  "
 338                         );
 339 #endif
 340
 341                 /* when a full LTC frame is decoded, the timecode the LTC frame
 342                  * is referring has just passed.
 343                  * So we send the _next_ timecode which
 344                  * is expected to start at the end of the current frame
 345                  */
 346                 int fps_i = ceil(timecode.rate);
 347
 348                 switch(fps_i) {
 349                         case 30:
 350                                 if (timecode.drop) {
 351                                         tv_standard = LTC_TV_525_60;
 352                                 } else {
 353                                         tv_standard = LTC_TV_1125_60;
 354                                 }
 355                                 break;
 356                         case 25:
 357                                 tv_standard = LTC_TV_625_50;
 358                                 break;
 359                         default:
 360                                 tv_standard = LTC_TV_FILM_24; /* == LTC_TV_1125_60 == no offset, 24,30fps BGF */
 361                                 break;
 362                 }
 363
 364                 if (!frame.reverse) {
 365                         ltc_frame_increment(&frame.ltc, fps_i, tv_standard, 0);
 366                         ltc_frame_to_time(&stime, &frame.ltc, 0);
 367                         transport_direction = 1;
 368                         frame.off_start -= ltc_frame_alignment(session.frames_per_timecode_frame(), tv_standard);
 369                         frame.off_end -= ltc_frame_alignment(session.frames_per_timecode_frame(), tv_standard);
 370                 } else {
 371                         ltc_frame_decrement(&frame.ltc, fps_i, tv_standard, 0);
 372                         int off = frame.off_end - frame.off_start;
 373                         frame.off_start += off - ltc_frame_alignment(session.frames_per_timecode_frame(), tv_standard);
 374                         frame.off_end += off - ltc_frame_alignment(session.frames_per_timecode_frame(), tv_standard);
 375                         transport_direction = -1;
 376                 }
 377
 378                 timecode.hours   = stime.hours;
 379                 timecode.minutes = stime.mins;
 380                 timecode.seconds = stime.secs;
 381                 timecode.frames  = stime.frame;
 382
 383                 /* map LTC timecode to session TC setting */
 384                 framepos_t ltc_frame; ///< audio-frame corresponding to LTC frame
 385                 Timecode::timecode_to_sample (timecode, ltc_frame, true, false,
 386                         double(session.frame_rate()),
 387                         session.config.get_subframes_per_frame(),
 388                         timecode_negative_offset, timecode_offset
 389                         );
 390
 391                 ltc_frame += ltc_slave_latency.max + session.worst_playback_latency();
 392
 393                 framepos_t cur_timestamp = frame.off_end + 1;
 394                 DEBUG_TRACE (DEBUG::LTC, string_compose ("LTC F: %1 LF: %2  N: %3 L: %4\n", ltc_frame, last_ltc_frame, cur_timestamp, last_timestamp));
 395                 if (frame.off_end + 1 <= last_timestamp || last_timestamp == 0) {
 396                         DEBUG_TRACE (DEBUG::LTC, string_compose ("LTC speed: UNCHANGED: %1\n", ltc_speed));
 397                 } else {
 398                         ltc_speed = double(ltc_frame - last_ltc_frame) / double(cur_timestamp - last_timestamp);
 399                         DEBUG_TRACE (DEBUG::LTC, string_compose ("LTC speed: %1\n", ltc_speed));
 400                 }
 401
 402                 if (fabs(ltc_speed) > 10.0) {
 403                         ltc_speed = 0;
 404                 }
 405
 406                 last_timestamp = frame.off_end + 1;
 407                 last_ltc_frame = ltc_frame;
 408         } /* end foreach decoded LTC frame */
 409 }
 410
 411 void
 412 LTC_Slave::init_engine_dll (framepos_t pos, int32_t inc)
 413 {
 414         double omega = 2.0 * M_PI * double(inc) / double(session.frame_rate());
 415         b = 1.4142135623730950488 * omega;
 416         c = omega * omega;
 417
 418         e2 = double(ltc_speed * inc);
 419         t0 = double(pos);
 420         t1 = t0 + e2;
 421         DEBUG_TRACE (DEBUG::LTC, string_compose ("[re-]init Engine DLL %1 %2 %3\n", t0, t1, e2));
 422 }
 423
 424 /* main entry point from session_process.cc
 425  * called from process callback context
 426  * so it is OK to use get_buffer()
 427  */
 428 bool
 429 LTC_Slave::speed_and_position (double& speed, framepos_t& pos)
 430 {
 431         bool engine_init_called = false;
 432         framepos_t now = session.engine().sample_time_at_cycle_start();
 433         framepos_t sess_pos = session.transport_frame(); // corresponds to now
 434         framecnt_t nframes = session.engine().samples_per_cycle();
 435
 436         Sample* in;
 437
 438         boost::shared_ptr<Port> ltcport = session.ltc_input_port();
 439
 440         in = (Sample*) AudioEngine::instance()->port_engine().get_buffer (ltcport->port_handle(), nframes);
 441
 442         frameoffset_t skip = now - (monotonic_cnt + nframes);
 443         monotonic_cnt = now;
 444         DEBUG_TRACE (DEBUG::LTC, string_compose ("speed_and_position - TID:%1 | latency: %2 | skip %3\n", pthread_name(), ltc_slave_latency.max, skip));
 445
 446         if (last_timestamp == 0) {
 447                 engine_dll_initstate = 0;
 448                 if (delayedlocked < 10) ++delayedlocked;
 449         } else if (engine_dll_initstate != transport_direction && ltc_speed != 0) {
 450
 451                 ActiveChanged (true); /* EMIT SIGNAL */
 452
 453                 engine_dll_initstate = transport_direction;
 454                 init_engine_dll(last_ltc_frame + rint(ltc_speed * double(2 * nframes + now - last_timestamp)),
 455                                 session.engine().samples_per_cycle());
 456                 engine_init_called = true;
 457         }
 458
 459         if (in) {
 460                 DEBUG_TRACE (DEBUG::LTC, string_compose ("LTC Process eng-tme: %1 eng-pos: %2\n", now, sess_pos));
 461                 /* when the jack-graph changes and if ardour performs
 462                  * locates, the audioengine is stopped (skipping frames) while
 463                  * jack [time] moves along.
 464                  */
 465                 if (skip > 0) {
 466                         DEBUG_TRACE (DEBUG::LTC, string_compose("engine skipped %1 frames. Feeding silence to LTC parser.\n", skip));
 467                         if (skip >= 8192) skip = 8192;
 468                         unsigned char sound[8192];
 469                         memset(sound, 0, sizeof(char) * skip);
 470                         ltc_decoder_write(decoder, sound, nframes, now);
 471                 } else if (skip != 0) {
 472                         /* this should never happen. it may if monotonic_cnt, now overflow on 64bit */
 473                         DEBUG_TRACE (DEBUG::LTC, string_compose("engine skipped %1 frames\n", skip));
 474                         reset();
 475                 }
 476
 477                 parse_ltc(nframes, in, now);
 478                 process_ltc(now);
 479         }
 480
 481         if (last_timestamp == 0) {
 482                 DEBUG_TRACE (DEBUG::LTC, "last timestamp == 0\n");
 483                 speed = 0;
 484                 pos = session.transport_frame();
 485                 return true;
 486         } else if (ltc_speed != 0) {
 487                 if (delayedlocked > 1) delayedlocked--;
 488                 else if (current_delta == 0) delayedlocked = 0;
 489         }
 490
 491         if (abs(now - last_timestamp) > FLYWHEEL_TIMEOUT) {
 492                 DEBUG_TRACE (DEBUG::LTC, "flywheel timeout\n");
 493                 reset();
 494                 speed = 0;
 495                 pos = session.transport_frame();
 496                 ActiveChanged (false); /* EMIT SIGNAL */
 497                 return true;
 498         }
 499
 500         /* it take 2 cycles from naught to rolling.
 501          * during these to initial cycles the speed == 0
 502          *
 503          * the first cycle:
 504          * DEBUG::Slave: slave stopped, move to NNN
 505          * DEBUG::Transport: Request forced locate to NNN
 506          * DEBUG::Slave: slave state 0 @ NNN speed 0 cur delta VERY-LARGE-DELTA avg delta 1800
 507          * DEBUG::Slave: silent motion
 508          * DEBUG::Transport: realtime stop @ NNN
 509          * DEBUG::Transport: Butler transport work, todo = PostTransportStop,PostTransportLocate,PostTransportClearSubstate
 510          *
 511          * [engine skips frames to locate, jack time keeps rolling on]
 512          *
 513          * the second cycle:
 514          *
 515          * DEBUG::LTC: [re-]init Engine DLL
 516          * DEBUG::Slave: slave stopped, move to NNN+
 517          * ...
 518          *
 519          * we need to seek two cycles ahead: 2 * nframes
 520          */
 521         if (engine_dll_initstate == 0) {
 522                 DEBUG_TRACE (DEBUG::LTC, "engine DLL not initialized. ltc_speed\n");
 523                 speed = 0;
 524                 pos = last_ltc_frame + rint(ltc_speed * double(2 * nframes + now - last_timestamp));
 525                 return true;
 526         }
 527
 528         /* interpolate position according to speed and time since last LTC-frame*/
 529         double speed_flt = ltc_speed;
 530         double elapsed = (now - last_timestamp) * speed_flt;
 531
 532         if (!engine_init_called) {
 533                 const double e = elapsed + double (last_ltc_frame - sess_pos);
 534                 t0 = t1;
 535                 t1 += b * e + e2;
 536                 e2 += c * e;
 537                 speed_flt = (t1 - t0) / double(session.engine().samples_per_cycle());
 538                 DEBUG_TRACE (DEBUG::LTC, string_compose ("LTC engine DLL t0:%1 t1:%2 err:%3 spd:%4 ddt:%5\n", t0, t1, e, speed_flt, e2 - session.engine().samples_per_cycle() ));
 539         } else {
 540                 DEBUG_TRACE (DEBUG::LTC, string_compose ("LTC adjusting elapsed (no DLL) from %1 by %2\n", elapsed, (2 * nframes * ltc_speed)));
 541                 speed_flt = 0;
 542                 elapsed += 2.0 * nframes * ltc_speed; /* see note above */
 543         }
 544
 545         pos = last_ltc_frame + rint(elapsed);
 546         speed = speed_flt;
 547         current_delta = (pos - sess_pos);
 548
 549         if (((pos < 0) || (labs(current_delta) > 2 * session.frame_rate()))) {
 550                 DEBUG_TRACE (DEBUG::LTC, string_compose ("LTC large drift: %1\n", current_delta));
 551                 reset();
 552                 speed = 0;
 553                 pos = session.transport_frame();
 554                 return true;
 555         }
 556
 557         DEBUG_TRACE (DEBUG::LTC, string_compose ("LTCsync spd: %1 pos: %2 | last-pos: %3 elapsed: %4 delta: %5\n",
 558                                                  speed, pos, last_ltc_frame, elapsed, current_delta));
 559
 560         /* provide a .1% deadzone to lock the speed */
 561         if (fabs(speed - 1.0) <= 0.001) {
 562                 speed = 1.0;
 563         }
 564
 565         if (speed != 0 && delayedlocked == 0 && fabs(speed) != 1.0) {
 566                 sync_lock_broken = true;
 567                 DEBUG_TRACE (DEBUG::LTC, string_compose ("LTC speed not locked %1 %2\n", speed, ltc_speed));
 568         }
 569
 570         return true;
 571 }
 572
 573 Timecode::TimecodeFormat
 574 LTC_Slave::apparent_timecode_format () const
 575 {
 576         if      (timecode.rate == 24 && !timecode.drop)
 577                 return timecode_24;
 578         else if (timecode.rate == 25 && !timecode.drop)
 579                 return timecode_25;
 580         else if (rint(timecode.rate * 100) == 2997 && !timecode.drop)
 581                 return (Config->get_timecode_source_2997() ? timecode_2997000 : timecode_2997);
 582         else if (rint(timecode.rate * 100) == 2997 &&  timecode.drop)
 583                 return (Config->get_timecode_source_2997() ? timecode_2997000drop : timecode_2997drop);
 584         else if (timecode.rate == 30 &&  timecode.drop)
 585                 return timecode_2997drop; // timecode_30drop; // LTC counting to 30 frames w/DF *means* 29.97 df
 586         else if (timecode.rate == 30 && !timecode.drop)
 587                 return timecode_30;
 588
 589         /* XXX - unknown timecode format */
 590         return session.config.get_timecode_format();
 591 }
 592
 593 std::string
 594 LTC_Slave::approximate_current_position() const
 595 {
 596         if (last_timestamp == 0) {
 597                 return " --:--:--:--";
 598         }
 599         return Timecode::timecode_format_time(timecode);
 600 }
 601
 602 std::string
 603 LTC_Slave::approximate_current_delta() const
 604 {
 605         char delta[80];
 606         if (last_timestamp == 0 || engine_dll_initstate == 0) {
 607                 snprintf(delta, sizeof(delta), "\u2012\u2012\u2012\u2012");
 608         } else if ((monotonic_cnt - last_timestamp) > 2 * frames_per_ltc_frame) {
 609                 snprintf(delta, sizeof(delta), "%s", _("flywheel"));
 610         } else {
 611                 snprintf(delta, sizeof(delta), "\u0394<span foreground=\"%s\" face=\"monospace\" >%s%s%lld</span>sm",
 612                                 sync_lock_broken ? "red" : "green",
 613                                 LEADINGZERO(::llabs(current_delta)), PLUSMINUS(-current_delta), ::llabs(current_delta));
 614         }
 615         return std::string(delta);
 616 }