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