modules/demux/smf.c

   1 /*****************************************************************************
   2  * smf.c : Standard MIDI File (.mid) demux module for vlc
   3  *****************************************************************************
   4  * Copyright © 2007 Rémi Denis-Courmont
   5  * $Id$
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU Lesser General Public License as published by
   9  * the Free Software Foundation; either version 2.1 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15  * GNU Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public License
  18  * along with this program; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  20  *****************************************************************************/
  21
  22 #ifdef HAVE_CONFIG_H
  23 # include "config.h"
  24 #endif
  25
  26 #include <vlc_common.h>
  27 #include <vlc_plugin.h>
  28 #include <vlc_demux.h>
  29 #include <vlc_charset.h>
  30 #include <limits.h>
  31
  32 #include <assert.h>
  33
  34 #define TEMPO_MIN  20
  35 #define TEMPO_MAX 250 /* Beats per minute */
  36
  37 /**
  38  * Reads MIDI variable length (7, 14, 21 or 28 bits) integer.
  39  * @return read value, or -1 on EOF/error.
  40  */
  41 static int32_t ReadVarInt (stream_t *s)
  42 {
  43     uint32_t val = 0;
  44     uint8_t byte;
  45
  46     for (unsigned i = 0; i < 4; i++)
  47     {
  48         if (vlc_stream_Read (s, &byte, 1) < 1)
  49             return -1;
  50
  51         val = (val << 7) | (byte & 0x7f);
  52         if ((byte & 0x80) == 0)
  53             return val;
  54     }
  55
  56     return -1;
  57 }
  58
  59 typedef struct smf_track_t
  60 {
  61     uint64_t next;   /*< Time of next message (in term of pulses) */
  62     uint64_t start;  /*< Start offset in the file */
  63     uint32_t length; /*< Bytes length */
  64     uint32_t offset; /*< Read offset relative to the start offset */
  65     uint8_t  running_event; /*< Running (previous) event */
  66 } mtrk_t;
  67
  68 /**
  69  * Reads (delta) time from the next event of a given track.
  70  * @param s stream to read data from (must be positioned at the right offset)
  71  */
  72 static int ReadDeltaTime (stream_t *s, mtrk_t *track)
  73 {
  74     int32_t delta_time;
  75
  76     assert (vlc_stream_Tell (s) == track->start + track->offset);
  77
  78     if (track->offset >= track->length)
  79     {
  80         /* This track is done */
  81         track->next = UINT64_MAX;
  82         return 0;
  83     }
  84
  85     delta_time = ReadVarInt (s);
  86     if (delta_time < 0)
  87         return -1;
  88
  89     track->next += delta_time;
  90     track->offset = vlc_stream_Tell (s) - track->start;
  91     return 0;
  92 }
  93
  94 struct demux_sys_t
  95 {
  96     es_out_id_t *es;
  97     date_t       pts; /*< Play timestamp */
  98     uint64_t     pulse; /*< Pulses counter */
  99     mtime_t      tick; /*< Last tick timestamp */
 100
 101     mtime_t      duration; /*< Total duration */
 102     unsigned     ppqn;   /*< Pulses Per Quarter Note */
 103     /* by the way, "quarter note" is "noire" in French */
 104
 105     unsigned     trackc; /*< Number of tracks */
 106     mtrk_t       trackv[]; /*< Track states */
 107 };
 108
 109 /**
 110  * Non-MIDI Meta events handler
 111  */
 112 static
 113 int HandleMeta (demux_t *p_demux, mtrk_t *tr)
 114 {
 115     stream_t *s = p_demux->s;
 116     demux_sys_t *p_sys = p_demux->p_sys;
 117     uint8_t *payload;
 118     uint8_t type;
 119     int32_t length;
 120     int ret = 0;
 121
 122     if (vlc_stream_Read (s, &type, 1) != 1)
 123         return -1;
 124
 125     length = ReadVarInt (s);
 126     if (length < 0)
 127         return -1;
 128
 129     payload = malloc (length + 1);
 130     if ((payload == NULL)
 131      || (vlc_stream_Read (s, payload, length) != length))
 132     {
 133         free (payload);
 134         return -1;
 135     }
 136
 137     payload[length] = '\0';
 138
 139     switch (type)
 140     {
 141         case 0x00: /* Sequence Number */
 142             break;
 143
 144         case 0x01: /* Text (comment) */
 145             EnsureUTF8 ((char *)payload);
 146             msg_Info (p_demux, "Text      : %s", (char *)payload);
 147             break;
 148
 149         case 0x02: /* Copyright */
 150             EnsureUTF8 ((char *)payload);
 151             msg_Info (p_demux, "Copyright : %s", (char *)payload);
 152             break;
 153
 154         case 0x03: /* Track name */
 155             EnsureUTF8 ((char *)payload);
 156             msg_Info (p_demux, "Track name: %s", (char *)payload);
 157             break;
 158
 159         case 0x04: /* Instrument name */
 160             EnsureUTF8 ((char *)payload);
 161             msg_Info (p_demux, "Instrument: %s", (char *)payload);
 162             break;
 163
 164         case 0x05: /* Lyric (one syllable) */
 165             /*EnsureUTF8 ((char *)payload);*/
 166             break;
 167
 168         case 0x06: /* Marker text */
 169             EnsureUTF8 ((char *)payload);
 170             msg_Info (p_demux, "Marker    : %s", (char *)payload);
 171             break;
 172
 173         case 0x07: /* Cue point (WAVE filename) */
 174             EnsureUTF8 ((char *)payload);
 175             msg_Info (p_demux, "Cue point : %s", (char *)payload);
 176             break;
 177
 178         case 0x08: /* Program/Patch name */
 179             EnsureUTF8 ((char *)payload);
 180             msg_Info (p_demux, "Patch name: %s", (char *)payload);
 181             break;
 182
 183         case 0x09: /* MIDI port name */
 184             EnsureUTF8 ((char *)payload);
 185             msg_Dbg (p_demux, "MIDI port : %s", (char *)payload);
 186             break;
 187
 188         case 0x2F: /* End of track */
 189             if (tr->start + tr->length != vlc_stream_Tell (s))
 190             {
 191                 msg_Err (p_demux, "misplaced end of track");
 192                 ret = -1;
 193             }
 194             break;
 195
 196         case 0x51: /* Tempo */
 197             if (length == 3)
 198             {
 199                 uint32_t uspqn = (payload[0] << 16)
 200                                | (payload[1] << 8) | payload[2];
 201                 unsigned tempo = 60 * 1000000 / (uspqn ? uspqn : 1);
 202                 msg_Dbg (p_demux, "tempo: %uus/qn -> %u BPM",
 203                          (unsigned)uspqn, tempo);
 204
 205                 if (tempo < TEMPO_MIN)
 206                 {
 207                     msg_Warn (p_demux, "tempo too slow -> %u BPM", TEMPO_MIN);
 208                     tempo = TEMPO_MIN;
 209                 }
 210                 else
 211                 if (tempo > TEMPO_MAX)
 212                 {
 213                     msg_Warn (p_demux, "tempo too fast -> %u BPM", TEMPO_MAX);
 214                     tempo = TEMPO_MAX;
 215                 }
 216                 date_Change (&p_sys->pts, p_sys->ppqn * tempo, 60);
 217             }
 218             else
 219                 ret = -1;
 220             break;
 221
 222         case 0x54: /* SMPTE offset */
 223             if (length == 5)
 224                 msg_Warn (p_demux, "SMPTE offset not implemented");
 225             else
 226                 ret = -1;
 227             break;
 228
 229         case 0x58: /* Time signature */
 230             if (length == 4)
 231                 ;
 232             else
 233                 ret = -1;
 234             break;
 235
 236         case 0x59: /* Key signature */
 237             if (length == 2)
 238                 ;
 239             else
 240                 ret = -1;
 241             break;
 242
 243         case 0x7f: /* Proprietary event */
 244             msg_Dbg (p_demux, "ignored proprietary SMF Meta Event (%d bytes)",
 245                      length);
 246             break;
 247
 248         default:
 249             msg_Warn (p_demux, "unknown SMF Meta Event type 0x%02X (%d bytes)",
 250                       type, length);
 251     }
 252
 253     free (payload);
 254     return ret;
 255 }
 256
 257 static
 258 int HandleMessage (demux_t *p_demux, mtrk_t *tr, es_out_t *out)
 259 {
 260     stream_t *s = p_demux->s;
 261     demux_sys_t *sys = p_demux->p_sys;
 262     block_t *block;
 263     uint8_t first, event;
 264     unsigned datalen;
 265
 266     if (vlc_stream_Seek (s, tr->start + tr->offset)
 267      || (vlc_stream_Read (s, &first, 1) != 1))
 268         return -1;
 269
 270     event = (first & 0x80) ? first : tr->running_event;
 271
 272     switch (event & 0xf0)
 273     {
 274         case 0xF0: /* System Exclusive */
 275             switch (event)
 276             {
 277                 case 0xF0: /* System Specific start */
 278                 case 0xF7: /* System Specific continuation */
 279                 {
 280                     /* Variable length followed by SysEx event data */
 281                     int32_t len = ReadVarInt (s);
 282                     if (len == -1)
 283                         return -1;
 284
 285                     block = vlc_stream_Block (s, len);
 286                     if (block == NULL)
 287                         return -1;
 288                     block = block_Realloc (block, 1, len);
 289                     if (block == NULL)
 290                         return -1;
 291                     block->p_buffer[0] = event;
 292                     goto send;
 293                 }
 294                 case 0xFF: /* SMF Meta Event */
 295                     if (HandleMeta (p_demux, tr))
 296                         return -1;
 297                     /* We MUST NOT pass this event forward. It would be
 298                      * confused as a MIDI Reset real-time event. */
 299                     goto skip;
 300                 case 0xF1:
 301                 case 0xF3:
 302                     datalen = 1;
 303                     break;
 304                 case 0xF2:
 305                     datalen = 2;
 306                     break;
 307                 case 0xF4:
 308                 case 0xF5:
 309                     /* We cannot handle undefined "common" (non-real-time)
 310                      * events inside SMF, as we cannot differentiate a
 311                      * one byte delta-time (< 0x80) from event data. */
 312                 default:
 313                     datalen = 0;
 314                     break;
 315             }
 316             break;
 317         case 0xC0:
 318         case 0xD0:
 319             datalen = 1;
 320             break;
 321         default:
 322             datalen = 2;
 323             break;
 324     }
 325
 326     /* FIXME: one message per block is very inefficient */
 327     block = block_Alloc (1 + datalen);
 328     if (block == NULL)
 329         goto skip;
 330
 331     block->p_buffer[0] = event;
 332     if (first & 0x80)
 333     {
 334         if (vlc_stream_Read(s, block->p_buffer + 1, datalen) < datalen)
 335             goto error;
 336     }
 337     else
 338     {
 339         if (datalen == 0)
 340         {   /* implicit running status requires non-empty payload */
 341             msg_Err (p_demux, "malformatted MIDI event");
 342             goto error;
 343         }
 344
 345         block->p_buffer[1] = first;
 346         if (datalen > 1
 347          && vlc_stream_Read(s, block->p_buffer + 2, datalen - 1) < datalen - 1)
 348             goto error;
 349     }
 350
 351 send:
 352     block->i_dts = block->i_pts = date_Get(&sys->pts);
 353     if (out != NULL)
 354         es_out_Send(out, sys->es, block);
 355     else
 356         block_Release (block);
 357
 358 skip:
 359     if (event < 0xF8)
 360         /* If event is not real-time, update running status */
 361         tr->running_event = event;
 362
 363     tr->offset = vlc_stream_Tell (s) - tr->start;
 364     return 0;
 365
 366 error:
 367     block_Release(block);
 368     return -1;
 369 }
 370
 371 static int SeekSet0 (demux_t *demux)
 372 {
 373     stream_t *stream = demux->s;
 374     demux_sys_t *sys = demux->p_sys;
 375
 376     /* Default SMF tempo is 120BPM, i.e. half a second per quarter note */
 377     date_Init (&sys->pts, sys->ppqn * 2, 1);
 378     date_Set (&sys->pts, VLC_TS_0);
 379     sys->pulse = 0;
 380     sys->tick = VLC_TS_0;
 381
 382     for (unsigned i = 0; i < sys->trackc; i++)
 383     {
 384         mtrk_t *tr = sys->trackv + i;
 385
 386         tr->offset = 0;
 387         tr->next = 0;
 388         /* Why 0xF6 (Tuning Calibration)?
 389          * Because it has zero bytes of data, so the parser will detect the
 390          * error if the first event uses running status. */
 391         tr->running_event = 0xF6;
 392
 393         if (vlc_stream_Seek (stream, tr->start)
 394          || ReadDeltaTime (stream, tr))
 395         {
 396             msg_Err (demux, "fatal parsing error");
 397             return -1;
 398         }
 399     }
 400
 401     return 0;
 402 }
 403
 404 static int ReadEvents (demux_t *demux, uint64_t *restrict pulse,
 405                        es_out_t *out)
 406 {
 407     uint64_t cur_pulse = *pulse, next_pulse = UINT64_MAX;
 408     demux_sys_t *sys = demux->p_sys;
 409
 410     for (unsigned i = 0; i < sys->trackc; i++)
 411     {
 412         mtrk_t *track = sys->trackv + i;
 413
 414         while (track->next <= cur_pulse)
 415         {
 416             if (HandleMessage (demux, track, out)
 417              || ReadDeltaTime (demux->s, track))
 418             {
 419                 msg_Err (demux, "fatal parsing error");
 420                 return -1;
 421             }
 422         }
 423
 424         if (next_pulse > track->next)
 425             next_pulse = track->next;
 426     }
 427
 428     if (next_pulse != UINT64_MAX)
 429         date_Increment (&sys->pts, next_pulse - cur_pulse);
 430     *pulse = next_pulse;
 431     return 0;
 432 }
 433
 434 #define TICK (CLOCK_FREQ / 100)
 435
 436 /*****************************************************************************
 437  * Demux: read chunks and send them to the synthesizer
 438  *****************************************************************************
 439  * Returns -1 in case of error, 0 in case of EOF, 1 otherwise
 440  *****************************************************************************/
 441 static int Demux (demux_t *demux)
 442 {
 443     demux_sys_t *sys = demux->p_sys;
 444
 445     /* MIDI Tick emulation (ping the decoder every 10ms) */
 446     if (sys->tick <= date_Get (&sys->pts))
 447     {
 448         block_t *tick = block_Alloc (1);
 449         if (unlikely(tick == NULL))
 450             return VLC_ENOMEM;
 451
 452         tick->p_buffer[0] = 0xF9;
 453         tick->i_dts = tick->i_pts = sys->tick;
 454
 455         es_out_Send (demux->out, sys->es, tick);
 456         es_out_SetPCR (demux->out, sys->tick);
 457
 458         sys->tick += TICK;
 459         return 1;
 460     }
 461
 462     /* MIDI events in chronological order across all tracks */
 463     uint64_t pulse = sys->pulse;
 464
 465     if (ReadEvents (demux, &pulse, demux->out))
 466         return VLC_EGENERIC;
 467
 468     if (pulse == UINT64_MAX)
 469         return 0; /* all tracks are done */
 470
 471     sys->pulse = pulse;
 472     return 1;
 473 }
 474
 475 static int Seek (demux_t *demux, mtime_t pts)
 476 {
 477     demux_sys_t *sys = demux->p_sys;
 478
 479     /* Rewind if needed */
 480     if (pts < date_Get (&sys->pts) && SeekSet0 (demux))
 481         return VLC_EGENERIC;
 482
 483     /* Fast forward */
 484     uint64_t pulse = sys->pulse;
 485
 486     while (pts > date_Get (&sys->pts))
 487     {
 488         if (pulse == UINT64_MAX)
 489             return VLC_SUCCESS; /* premature end */
 490         if (ReadEvents (demux, &pulse, NULL))
 491             return VLC_EGENERIC;
 492     }
 493
 494     sys->pulse = pulse;
 495     sys->tick = ((date_Get (&sys->pts) - VLC_TS_0) / TICK) * TICK + VLC_TS_0;
 496     return VLC_SUCCESS;
 497 }
 498
 499 /*****************************************************************************
 500  * Control:
 501  *****************************************************************************/
 502 static int Control (demux_t *demux, int i_query, va_list args)
 503 {
 504     demux_sys_t *sys = demux->p_sys;
 505
 506     switch (i_query)
 507     {
 508         case DEMUX_CAN_SEEK:
 509             *va_arg (args, bool *) = true;
 510             break;
 511         case DEMUX_GET_POSITION:
 512             if (!sys->duration)
 513                 return VLC_EGENERIC;
 514             *va_arg (args, double *) = (sys->tick - (double)VLC_TS_0)
 515                                      / sys->duration;
 516             break;
 517         case DEMUX_SET_POSITION:
 518             return Seek (demux, va_arg (args, double) * sys->duration);
 519         case DEMUX_GET_LENGTH:
 520             *va_arg (args, int64_t *) = sys->duration;
 521             break;
 522         case DEMUX_GET_TIME:
 523             *va_arg (args, int64_t *) = sys->tick - VLC_TS_0;
 524             break;
 525         case DEMUX_SET_TIME:
 526             return Seek (demux, va_arg (args, int64_t));
 527
 528         case DEMUX_CAN_PAUSE:
 529         case DEMUX_SET_PAUSE_STATE:
 530         case DEMUX_CAN_CONTROL_PACE:
 531         case DEMUX_GET_PTS_DELAY:
 532             return demux_vaControlHelper( demux->s, 0, -1, 0, 1, i_query, args );
 533
 534         default:
 535             return VLC_EGENERIC;
 536     }
 537     return VLC_SUCCESS;
 538 }
 539
 540 /**
 541  * Probes file format and starts demuxing.
 542  */
 543 static int Open (vlc_object_t *obj)
 544 {
 545     demux_t *demux = (demux_t *)obj;
 546     stream_t *stream = demux->s;
 547     const uint8_t *peek;
 548     bool multitrack;
 549
 550     /* (Try to) parse the SMF header */
 551     /* Header chunk always has 6 bytes payload */
 552     if (vlc_stream_Peek (stream, &peek, 14) < 14)
 553         return VLC_EGENERIC;
 554
 555     /* Skip RIFF MIDI header if present */
 556     if (!memcmp (peek, "RIFF", 4) && !memcmp (peek + 8, "RMID", 4))
 557     {
 558         uint32_t riff_len = GetDWLE (peek + 4);
 559
 560         msg_Dbg (demux, "detected RIFF MIDI file (%"PRIu32" bytes)", riff_len);
 561         if ((vlc_stream_Read (stream, NULL, 12) < 12))
 562             return VLC_EGENERIC;
 563
 564         /* Look for the RIFF data chunk */
 565         for (;;)
 566         {
 567             char chnk_hdr[8];
 568             uint32_t chnk_len;
 569
 570             if ((riff_len < 8)
 571              || (vlc_stream_Read (stream, chnk_hdr, 8) < 8))
 572                 return VLC_EGENERIC;
 573
 574             riff_len -= 8;
 575             chnk_len = GetDWLE (chnk_hdr + 4);
 576             if (riff_len < chnk_len)
 577                 return VLC_EGENERIC;
 578             riff_len -= chnk_len;
 579
 580             if (!memcmp (chnk_hdr, "data", 4))
 581                 break; /* found! */
 582
 583             if (vlc_stream_Read (stream, NULL, chnk_len) < (ssize_t)chnk_len)
 584                 return VLC_EGENERIC;
 585         }
 586
 587         /* Read real SMF header. Assume RIFF data chunk length is proper. */
 588         if (vlc_stream_Peek (stream, &peek, 14) < 14)
 589             return VLC_EGENERIC;
 590     }
 591
 592     if (memcmp (peek, "MThd\x00\x00\x00\x06", 8))
 593         return VLC_EGENERIC;
 594     peek += 8;
 595
 596     /* First word: SMF type */
 597     switch (GetWBE (peek))
 598     {
 599         case 0:
 600             multitrack = false;
 601             break;
 602         case 1:
 603             multitrack = true;
 604             break;
 605         default:
 606             /* We don't implement SMF2 (as do many) */
 607             msg_Err (demux, "unsupported SMF file type %u", GetWBE (peek));
 608             return VLC_EGENERIC;
 609     }
 610     peek += 2;
 611
 612     /* Second word: number of tracks */
 613     unsigned tracks = GetWBE (peek);
 614     peek += 2;
 615     if (!multitrack && (tracks != 1))
 616     {
 617         msg_Err (demux, "invalid SMF type 0 file");
 618         return VLC_EGENERIC;
 619     }
 620
 621     msg_Dbg (demux, "detected Standard MIDI File (type %u) with %u track(s)",
 622              multitrack, tracks);
 623
 624     /* Third/last word: timing */
 625     unsigned ppqn = GetWBE (peek);
 626     if (ppqn & 0x8000)
 627     {   /* FIXME */
 628         msg_Err (demux, "SMPTE timestamps not implemented");
 629         return VLC_EGENERIC;
 630     }
 631     else
 632     {
 633         if (ppqn == 0)
 634         {
 635             msg_Err(demux, "invalid SMF file PPQN: %u", ppqn);
 636             return VLC_EGENERIC;
 637         }
 638         msg_Dbg (demux, " %u pulses per quarter note", ppqn);
 639     }
 640
 641     demux_sys_t *sys = malloc (sizeof (*sys) + (sizeof (mtrk_t) * tracks));
 642     if (unlikely(sys == NULL))
 643         return VLC_ENOMEM;
 644
 645     /* We've had a valid SMF header - now skip it*/
 646     if (vlc_stream_Read (stream, NULL, 14) < 14)
 647         goto error;
 648
 649     demux->p_sys = sys;
 650     sys->duration = 0;
 651     sys->ppqn = ppqn;
 652     sys->trackc = tracks;
 653
 654     /* Prefetch track offsets */
 655     for (unsigned i = 0; i < tracks; i++)
 656     {
 657         mtrk_t *tr = sys->trackv + i;
 658         uint8_t head[8];
 659
 660         /* Seeking screws streaming up, but there is no way around this, as
 661          * SMF1 tracks are performed simultaneously.
 662          * Not a big deal as SMF1 are usually only a few kbytes anyway. */
 663         if (i > 0 && vlc_stream_Seek (stream, tr[-1].start + tr[-1].length))
 664         {
 665             msg_Err (demux, "cannot build SMF index (corrupted file?)");
 666             goto error;
 667         }
 668
 669         for (;;)
 670         {
 671             if (vlc_stream_Read (stream, head, 8) < 8)
 672             {
 673                 /* FIXME: don't give up if we have at least one valid track */
 674                 msg_Err (demux, "incomplete SMF chunk, file is corrupted");
 675                 goto error;
 676             }
 677
 678             if (memcmp (head, "MTrk", 4) == 0)
 679                 break;
 680
 681             uint_fast32_t chunk_len = GetDWBE(head + 4);
 682             msg_Dbg(demux, "skipping unknown SMF chunk (%"PRIuFAST32" bytes)",
 683                     chunk_len);
 684             if (vlc_stream_Seek(stream, vlc_stream_Tell(stream) + chunk_len))
 685                 goto error;
 686         }
 687
 688         tr->start = vlc_stream_Tell (stream);
 689         tr->length = GetDWBE (head + 4);
 690     }
 691
 692     bool b;
 693     if (vlc_stream_Control (stream, STREAM_CAN_FASTSEEK, &b) == 0 && b)
 694     {
 695         if (SeekSet0 (demux))
 696             goto error;
 697
 698         for (uint64_t pulse = 0; pulse != UINT64_MAX;)
 699              if (ReadEvents (demux, &pulse, NULL))
 700                  break;
 701
 702         sys->duration = date_Get (&sys->pts);
 703     }
 704
 705     if (SeekSet0 (demux))
 706         goto error;
 707
 708     es_format_t  fmt;
 709     es_format_Init (&fmt, AUDIO_ES, VLC_CODEC_MIDI);
 710     fmt.audio.i_channels = 2;
 711     fmt.audio.i_rate = 44100; /* dummy value */
 712     sys->es = es_out_Add (demux->out, &fmt);
 713
 714     demux->pf_demux = Demux;
 715     demux->pf_control = Control;
 716     return VLC_SUCCESS;
 717
 718 error:
 719     free (sys);
 720     return VLC_EGENERIC;
 721 }
 722
 723 /**
 724  * Releases allocate resources.
 725  */
 726 static void Close (vlc_object_t * p_this)
 727 {
 728     demux_t *p_demux = (demux_t *)p_this;
 729     demux_sys_t *p_sys = p_demux->p_sys;
 730
 731     free (p_sys);
 732 }
 733
 734 vlc_module_begin ()
 735     set_description (N_("SMF demuxer"))
 736     set_category (CAT_INPUT)
 737     set_subcategory (SUBCAT_INPUT_DEMUX)
 738     set_capability ("demux", 20)
 739     set_callbacks (Open, Close)
 740 vlc_module_end ()