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