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