libs/midi++2/mtc.cc

   1 /*
   2     Copyright (C) 2004 Paul Barton-Davis
   3
   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.
   8
   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.
  13
  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.
  17
  18     $Id$
  19 */
  20
  21 #include <cstdlib>
  22 #include <unistd.h>
  23 #include <cstring>
  24 #include <iostream>
  25
  26 #include "midi++/types.h"
  27 #include "midi++/parser.h"
  28 #include "midi++/port.h"
  29 #include "midi++/mmc.h"
  30 #include "pbd/transmitter.h"
  31
  32 using namespace std;
  33 using namespace sigc;
  34 using namespace MIDI;
  35
  36 bool
  37 Parser::possible_mtc (byte *sysex_buf, size_t msglen)
  38 {
  39         byte fake_mtc_time[5];
  40
  41         if (msglen != 10 || sysex_buf[0] != 0xf0 || sysex_buf[1] != 0x7f || sysex_buf[3] != 0x01 || sysex_buf[4] != 0x01) {
  42                 return false;
  43         }
  44
  45         /* full MTC */
  46
  47         fake_mtc_time[0] = sysex_buf[8]; // frames
  48         fake_mtc_time[1] = sysex_buf[7]; // minutes
  49         fake_mtc_time[2] = sysex_buf[6]; // seconds
  50         fake_mtc_time[3] = (sysex_buf[5] & 0x1f); // hours
  51
  52         _mtc_fps = MTC_FPS ((sysex_buf[5] & 0x60) >> 5); // fps
  53         fake_mtc_time[4] = (byte) _mtc_fps;
  54
  55         /* wait for first quarter frame, which could indicate forwards
  56            or backwards ...
  57         */
  58
  59         reset_mtc_state ();
  60
  61         /* emit signals */
  62
  63         mtc (*this, &sysex_buf[1], msglen - 1);
  64         mtc_time (fake_mtc_time, true, _timestamp);
  65         mtc_status (MTC_Stopped);
  66
  67         return true;
  68 }
  69
  70 void
  71 Parser::reset_mtc_state ()
  72 {
  73         /* MUST REMAIN RT-SAFE */
  74
  75         _mtc_forward = false;
  76         _mtc_running = MTC_Stopped;
  77         _mtc_locked = false;
  78         expected_mtc_quarter_frame_code = 0;
  79         memset (_mtc_time, 0, sizeof (_mtc_time));
  80         memset (_qtr_mtc_time, 0, sizeof (_mtc_time));
  81         consecutive_qtr_frame_cnt = 0;
  82         last_qtr_frame = 0;
  83 }
  84
  85 void
  86 Parser::process_mtc_quarter_frame (byte *msg)
  87 {
  88         int which_quarter_frame = (msg[1] & 0xf0) >> 4;
  89
  90         /* Is it an expected frame?
  91            Remember, the first can be frame 7 or frame 0,
  92            depending on the direction of the MTC generator ...
  93         */
  94
  95 #ifdef DEBUG_MTC
  96          cerr << "MTC: (state = " << _mtc_running << ") "
  97               << which_quarter_frame << " vs. " << expected_mtc_quarter_frame_code
  98               << " consecutive ? " << consecutive_qtr_frame_cnt
  99               << endl;
 100 #endif
 101
 102         if (_mtc_running == MTC_Stopped) {
 103
 104                 /* we are stopped but are seeing qtr frame messages */
 105
 106                 if (consecutive_qtr_frame_cnt == 0) {
 107
 108                         /* first quarter frame */
 109
 110                         if (which_quarter_frame != 0 && which_quarter_frame != 7) {
 111
 112                                 last_qtr_frame = which_quarter_frame;
 113                                 consecutive_qtr_frame_cnt++;
 114                         }
 115
 116                         // cerr << "first seen qframe = " << (int) last_qtr_frame << endl;
 117
 118                         return;
 119
 120                 } else if (consecutive_qtr_frame_cnt == 1) {
 121
 122                         /* third quarter frame */
 123
 124                         // cerr << "second seen qframe = " << (int) which_quarter_frame << endl;
 125
 126                         if (last_qtr_frame < which_quarter_frame) {
 127                                 _mtc_running = MTC_Forward;
 128                         } else if (last_qtr_frame > which_quarter_frame) {
 129                                 _mtc_running = MTC_Backward;
 130                         }
 131
 132                         mtc_status (_mtc_running);
 133                 }
 134
 135                 switch (_mtc_running) {
 136                 case MTC_Forward:
 137                         if (which_quarter_frame == 7) {
 138                                 expected_mtc_quarter_frame_code = 0;
 139                         } else {
 140                                 expected_mtc_quarter_frame_code = which_quarter_frame + 1;
 141                         }
 142                         break;
 143
 144                 case MTC_Backward:
 145                         if (which_quarter_frame == 0) {
 146                                 expected_mtc_quarter_frame_code = 7;
 147
 148                         } else {
 149                                 expected_mtc_quarter_frame_code = which_quarter_frame - 1;
 150                         }
 151                         break;
 152
 153                 case MTC_Stopped:
 154                         break;
 155                 }
 156
 157         } else {
 158
 159                 /* already running */
 160
 161 // for testing bad MIDI connections etc.
 162 //              if ((random() % 500) < 10) {
 163
 164                 if (which_quarter_frame != expected_mtc_quarter_frame_code) {
 165
 166                         consecutive_qtr_frame_cnt = 0;
 167
 168 #ifdef DEBUG_MTC
 169                         cerr << "MTC: (state = " << _mtc_running << ") "
 170                              << which_quarter_frame << " vs. " << expected_mtc_quarter_frame_code << endl;
 171 #endif
 172
 173                         /* tell listener(s) that we skipped. if they return
 174                            true, just ignore this in terms of it being an error.
 175                         */
 176
 177                         if (1) { /* mtc_skipped () */
 178
 179                                 /* no error, reset next expected frame */
 180
 181                                 switch (_mtc_running) {
 182                                 case MTC_Forward:
 183                                         if (which_quarter_frame == 7) {
 184                                                 expected_mtc_quarter_frame_code = 0;
 185                                         } else {
 186                                                 expected_mtc_quarter_frame_code = which_quarter_frame + 1;
 187                                         }
 188                                         break;
 189
 190                                 case MTC_Backward:
 191                                         if (which_quarter_frame == 0) {
 192                                                 expected_mtc_quarter_frame_code = 7;
 193
 194                                         } else {
 195                                                 expected_mtc_quarter_frame_code = which_quarter_frame - 1;
 196                                         }
 197                                         break;
 198
 199                                 case MTC_Stopped:
 200                                         break;
 201                                 }
 202
 203 #ifdef DEBUG_MTC
 204                                 cerr << "SKIPPED, next expected = " << expected_mtc_quarter_frame_code << endl;
 205 #endif
 206                                 return;
 207                         }
 208
 209                         /* go back to waiting for the first frame */
 210
 211                         expected_mtc_quarter_frame_code = 0;
 212                         memset (_qtr_mtc_time, 0, sizeof (_qtr_mtc_time));
 213
 214                         _mtc_running = MTC_Stopped;
 215                         _mtc_locked = false;
 216                         mtc_status (MTC_Stopped);
 217
 218                         return;
 219
 220                 } else {
 221
 222                         /* received qtr frame matched expected */
 223                         consecutive_qtr_frame_cnt++;
 224
 225                 }
 226         }
 227
 228         /* time code is looking good */
 229
 230 #ifdef DEBUG_MTC
 231         // cerr << "for quarter frame " << which_quarter_frame << " byte = " << hex << (int) msg[1] << dec << endl;
 232 #endif
 233
 234         switch (which_quarter_frame) {
 235         case 0: // frames LS nibble
 236                 _qtr_mtc_time[0] |= msg[1] & 0xf;
 237                 break;
 238
 239         case 1:  // frames MS nibble
 240                 _qtr_mtc_time[0] |= (msg[1] & 0xf)<<4;
 241                 break;
 242
 243         case 2: // seconds LS nibble
 244                 _qtr_mtc_time[1] |= msg[1] & 0xf;
 245                 break;
 246
 247         case 3: // seconds MS nibble
 248                 _qtr_mtc_time[1] |= (msg[1] & 0xf)<<4;
 249                 break;
 250
 251         case 4: // minutes LS nibble
 252                 _qtr_mtc_time[2] |= msg[1] & 0xf;
 253                 break;
 254
 255         case 5: // minutes MS nibble
 256                 _qtr_mtc_time[2] |= (msg[1] & 0xf)<<4;
 257                 break;
 258
 259         case 6: // hours LS nibble
 260                 _qtr_mtc_time[3] |= msg[1] & 0xf;
 261                 break;
 262
 263         case 7:
 264
 265                 /* last quarter frame msg has the MS bit of
 266                    the hour in bit 0, and the SMPTE FPS type
 267                    in bits 5 and 6
 268                 */
 269
 270                 _qtr_mtc_time[3] |= ((msg[1] & 0x1) << 4);
 271                 _mtc_fps = MTC_FPS ((msg[1] & 0x6) >> 1);
 272                 _qtr_mtc_time[4] = _mtc_fps;
 273                 break;
 274
 275         default:
 276                 /*NOTREACHED*/
 277                 break;
 278
 279         }
 280
 281 #ifdef DEBUG_MTC
 282         cerr << "Emit MTC Qtr\n";
 283 #endif
 284
 285         mtc_qtr (*this, which_quarter_frame, _timestamp); /* EMIT_SIGNAL */
 286
 287         // mtc (*this, &msg[1], msglen - 1);
 288
 289         switch (_mtc_running) {
 290         case MTC_Forward:
 291                 if ((which_quarter_frame == 7)) {
 292
 293                         /* we've reached the final of 8 quarter frame messages.
 294                            store the time, reset the pending time holder,
 295                            and signal anyone who wants to know the time.
 296                         */
 297
 298                         if (consecutive_qtr_frame_cnt >= 8) {
 299                                 memcpy (_mtc_time, _qtr_mtc_time, sizeof (_mtc_time));
 300                                 memset (_qtr_mtc_time, 0, sizeof (_qtr_mtc_time));
 301                                 if (!_mtc_locked) {
 302                                         _mtc_locked = true;
 303                                 }
 304
 305                                 mtc_time (_mtc_time, false, _timestamp);
 306                         }
 307                         expected_mtc_quarter_frame_code = 0;
 308
 309                 } else {
 310                         expected_mtc_quarter_frame_code = which_quarter_frame + 1;
 311                 }
 312                 break;
 313
 314         case MTC_Backward:
 315                 if (which_quarter_frame == 0) {
 316
 317                         /* we've reached the final of 8 quarter frame messages.
 318                            store the time, reset the pending time holder,
 319                            and signal anyone who wants to know the time.
 320                         */
 321
 322                         if (consecutive_qtr_frame_cnt >= 8) {
 323                                 memcpy (_mtc_time, _qtr_mtc_time, sizeof (_mtc_time));
 324                                 memset (_qtr_mtc_time, 0, sizeof (_qtr_mtc_time));
 325                                 if (!_mtc_locked) {
 326                                         _mtc_locked = true;
 327                                 }
 328                                 mtc_time (_mtc_time, false, _timestamp);
 329                         }
 330
 331                         expected_mtc_quarter_frame_code = 7;
 332
 333                 } else {
 334                         expected_mtc_quarter_frame_code = which_quarter_frame - 1;
 335                 }
 336                 break;
 337
 338         default:
 339                 break;
 340         }
 341
 342 }