modules/access/rtp/rtp.c

   1 /**
   2  * @file rtp.c
   3  * @brief Real-Time Protocol (RTP) demux module for VLC media player
   4  */
   5 /*****************************************************************************
   6  * Copyright (C) 2001-2005 the VideoLAN team
   7  * Copyright © 2007-2009 Rémi Denis-Courmont
   8  *
   9  * This library is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License
  11  * as published by the Free Software Foundation; either version 2
  12  * of the License, or (at your option) any later version.
  13  *
  14  * This library is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public
  20  * License along with this library; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  22  ****************************************************************************/
  23
  24 #ifdef HAVE_CONFIG_H
  25 # include <config.h>
  26 #endif
  27 #include <stdarg.h>
  28 #include <assert.h>
  29 #include <errno.h>
  30
  31 #include <vlc_common.h>
  32 #include <vlc_demux.h>
  33 #include <vlc_aout.h>
  34 #include <vlc_network.h>
  35 #include <vlc_plugin.h>
  36
  37 #include "rtp.h"
  38 #ifdef HAVE_SRTP
  39 # include <srtp.h>
  40 #endif
  41
  42 #define RTP_CACHING_TEXT N_("RTP de-jitter buffer length (msec)")
  43 #define RTP_CACHING_LONGTEXT N_( \
  44     "How long to wait for late RTP packets (and delay the performance)." )
  45
  46 #define RTCP_PORT_TEXT N_("RTCP (local) port")
  47 #define RTCP_PORT_LONGTEXT N_( \
  48     "RTCP packets will be received on this transport protocol port. " \
  49     "If zero, multiplexed RTP/RTCP is used.")
  50
  51 #define SRTP_KEY_TEXT N_("SRTP key (hexadecimal)")
  52 #define SRTP_KEY_LONGTEXT N_( \
  53     "RTP packets will be authenticated and deciphered "\
  54     "with this Secure RTP master shared secret key.")
  55
  56 #define SRTP_SALT_TEXT N_("SRTP salt (hexadecimal)")
  57 #define SRTP_SALT_LONGTEXT N_( \
  58     "Secure RTP requires a (non-secret) master salt value.")
  59
  60 #define RTP_MAX_SRC_TEXT N_("Maximum RTP sources")
  61 #define RTP_MAX_SRC_LONGTEXT N_( \
  62     "How many distinct active RTP sources are allowed at a time." )
  63
  64 #define RTP_TIMEOUT_TEXT N_("RTP source timeout (sec)")
  65 #define RTP_TIMEOUT_LONGTEXT N_( \
  66     "How long to wait for any packet before a source is expired.")
  67
  68 #define RTP_MAX_DROPOUT_TEXT N_("Maximum RTP sequence number dropout")
  69 #define RTP_MAX_DROPOUT_LONGTEXT N_( \
  70     "RTP packets will be discarded if they are too much ahead (i.e. in the " \
  71     "future) by this many packets from the last received packet." )
  72
  73 #define RTP_MAX_MISORDER_TEXT N_("Maximum RTP sequence number misordering")
  74 #define RTP_MAX_MISORDER_LONGTEXT N_( \
  75     "RTP packets will be discarded if they are too far behind (i.e. in the " \
  76     "past) by this many packets from the last received packet." )
  77
  78 static int  Open (vlc_object_t *);
  79 static void Close (vlc_object_t *);
  80
  81 /*
  82  * Module descriptor
  83  */
  84 vlc_module_begin ()
  85     set_shortname (N_("RTP"))
  86     set_description (N_("Real-Time Protocol (RTP) input"))
  87     set_category (CAT_INPUT)
  88     set_subcategory (SUBCAT_INPUT_DEMUX)
  89     set_capability ("access_demux", 0)
  90     set_callbacks (Open, Close)
  91
  92     add_integer ("rtp-caching", 1000, NULL, RTP_CACHING_TEXT,
  93                  RTP_CACHING_LONGTEXT, true)
  94         change_integer_range (0, 65535)
  95         change_safe ()
  96     add_integer ("rtcp-port", 0, NULL, RTCP_PORT_TEXT,
  97                  RTCP_PORT_LONGTEXT, false)
  98         change_integer_range (0, 65535)
  99         change_safe ()
 100 #ifdef HAVE_SRTP
 101     add_string ("srtp-key", "",
 102                 SRTP_KEY_TEXT, SRTP_KEY_LONGTEXT, false)
 103     add_string ("srtp-salt", "",
 104                 SRTP_SALT_TEXT, SRTP_SALT_LONGTEXT, false)
 105 #endif
 106     add_integer ("rtp-max-src", 1, NULL, RTP_MAX_SRC_TEXT,
 107                  RTP_MAX_SRC_LONGTEXT, true)
 108         change_integer_range (1, 255)
 109     add_integer ("rtp-timeout", 5, NULL, RTP_TIMEOUT_TEXT,
 110                  RTP_TIMEOUT_LONGTEXT, true)
 111     add_integer ("rtp-max-dropout", 3000, NULL, RTP_MAX_DROPOUT_TEXT,
 112                  RTP_MAX_DROPOUT_LONGTEXT, true)
 113         change_integer_range (0, 32767)
 114     add_integer ("rtp-max-misorder", 100, NULL, RTP_MAX_MISORDER_TEXT,
 115                  RTP_MAX_MISORDER_LONGTEXT, true)
 116         change_integer_range (0, 32767)
 117
 118     /*add_shortcut ("sctp")*/
 119     add_shortcut ("dccp", "rtptcp", /* "tcp" is already taken :( */
 120                   "rtp", "udplite")
 121 vlc_module_end ()
 122
 123 /*
 124  * TODO: so much stuff
 125  * - send RTCP-RR and RTCP-BYE
 126  * - dynamic payload types (need SDP parser)
 127  * - multiple medias (need SDP parser, and RTCP-SR parser for lip-sync)
 128  * - support for stream_filter in case of stream_Demux (MPEG-TS)
 129  */
 130
 131 #ifndef IPPROTO_DCCP
 132 # define IPPROTO_DCCP 33 /* IANA */
 133 #endif
 134
 135 #ifndef IPPROTO_UDPLITE
 136 # define IPPROTO_UDPLITE 136 /* from IANA */
 137 #endif
 138
 139
 140 /*
 141  * Local prototypes
 142  */
 143 static int Control (demux_t *, int i_query, va_list args);
 144 static int extract_port (char **phost);
 145
 146 /**
 147  * Probes and initializes.
 148  */
 149 static int Open (vlc_object_t *obj)
 150 {
 151     demux_t *demux = (demux_t *)obj;
 152     int tp; /* transport protocol */
 153
 154     if (!strcmp (demux->psz_access, "dccp"))
 155         tp = IPPROTO_DCCP;
 156     else
 157     if (!strcmp (demux->psz_access, "rtptcp"))
 158         tp = IPPROTO_TCP;
 159     else
 160     if (!strcmp (demux->psz_access, "rtp"))
 161         tp = IPPROTO_UDP;
 162     else
 163     if (!strcmp (demux->psz_access, "udplite"))
 164         tp = IPPROTO_UDPLITE;
 165     else
 166         return VLC_EGENERIC;
 167
 168     char *tmp = strdup (demux->psz_location);
 169     if (tmp == NULL)
 170         return VLC_ENOMEM;
 171
 172     char *shost;
 173     char *dhost = strchr (tmp, '@');
 174     if (dhost != NULL)
 175     {
 176         *(dhost++) = '\0';
 177         shost = tmp;
 178     }
 179     else
 180     {
 181         dhost = tmp;
 182         shost = NULL;
 183     }
 184
 185     /* Parses the port numbers */
 186     int sport = 0, dport = 0;
 187     if (shost != NULL)
 188         sport = extract_port (&shost);
 189     if (dhost != NULL)
 190         dport = extract_port (&dhost);
 191     if (dport == 0)
 192         dport = 5004; /* avt-profile-1 port */
 193
 194     int rtcp_dport = var_CreateGetInteger (obj, "rtcp-port");
 195
 196     /* Try to connect */
 197     int fd = -1, rtcp_fd = -1;
 198
 199     switch (tp)
 200     {
 201         case IPPROTO_UDP:
 202         case IPPROTO_UDPLITE:
 203             fd = net_OpenDgram (obj, dhost, dport,
 204                                 shost, sport, AF_UNSPEC, tp);
 205             if (fd == -1)
 206                 break;
 207             if (rtcp_dport > 0) /* XXX: source port is unknown */
 208                 rtcp_fd = net_OpenDgram (obj, dhost, rtcp_dport, shost, 0,
 209                                          AF_UNSPEC, tp);
 210             break;
 211
 212          case IPPROTO_DCCP:
 213 #ifndef SOCK_DCCP /* provisional API (FIXME) */
 214 # ifdef __linux__
 215 #  define SOCK_DCCP 6
 216 # endif
 217 #endif
 218 #ifdef SOCK_DCCP
 219             var_Create (obj, "dccp-service", VLC_VAR_STRING);
 220             var_SetString (obj, "dccp-service", "RTPV"); /* FIXME: RTPA? */
 221             fd = net_Connect (obj, dhost, dport, SOCK_DCCP, tp);
 222 #else
 223             msg_Err (obj, "DCCP support not included");
 224 #endif
 225             break;
 226
 227         case IPPROTO_TCP:
 228             fd = net_Connect (obj, dhost, dport, SOCK_STREAM, tp);
 229             break;
 230     }
 231
 232     free (tmp);
 233     if (fd == -1)
 234         return VLC_EGENERIC;
 235     net_SetCSCov (fd, -1, 12);
 236
 237     /* Initializes demux */
 238     demux_sys_t *p_sys = malloc (sizeof (*p_sys));
 239     if (p_sys == NULL)
 240     {
 241         net_Close (fd);
 242         if (rtcp_fd != -1)
 243             net_Close (rtcp_fd);
 244         return VLC_EGENERIC;
 245     }
 246
 247     vlc_mutex_init (&p_sys->lock);
 248 #ifdef HAVE_SRTP
 249     p_sys->srtp         = NULL;
 250 #endif
 251     p_sys->fd           = fd;
 252     p_sys->rtcp_fd      = rtcp_fd;
 253     p_sys->caching      = var_CreateGetInteger (obj, "rtp-caching");
 254     p_sys->max_src      = var_CreateGetInteger (obj, "rtp-max-src");
 255     p_sys->timeout      = var_CreateGetInteger (obj, "rtp-timeout")
 256                         * CLOCK_FREQ;
 257     p_sys->max_dropout  = var_CreateGetInteger (obj, "rtp-max-dropout");
 258     p_sys->max_misorder = var_CreateGetInteger (obj, "rtp-max-misorder");
 259     p_sys->framed_rtp   = (tp == IPPROTO_TCP);
 260
 261     demux->pf_demux   = NULL;
 262     demux->pf_control = Control;
 263     demux->p_sys      = p_sys;
 264
 265     p_sys->session = rtp_session_create (demux);
 266     if (p_sys->session == NULL)
 267         goto error;
 268
 269 #ifdef HAVE_SRTP
 270     char *key = var_CreateGetNonEmptyString (demux, "srtp-key");
 271     if (key)
 272     {
 273         p_sys->srtp = srtp_create (SRTP_ENCR_AES_CM, SRTP_AUTH_HMAC_SHA1, 10,
 274                                    SRTP_PRF_AES_CM, SRTP_RCC_MODE1);
 275         if (p_sys->srtp == NULL)
 276         {
 277             free (key);
 278             goto error;
 279         }
 280
 281         char *salt = var_CreateGetNonEmptyString (demux, "srtp-salt");
 282         errno = srtp_setkeystring (p_sys->srtp, key, salt ? salt : "");
 283         free (salt);
 284         free (key);
 285         if (errno)
 286         {
 287             msg_Err (obj, "bad SRTP key/salt combination (%m)");
 288             goto error;
 289         }
 290     }
 291 #endif
 292
 293     if (vlc_clone (&p_sys->thread, rtp_thread, demux,
 294                    VLC_THREAD_PRIORITY_INPUT))
 295         goto error;
 296     p_sys->thread_ready = true;
 297     return VLC_SUCCESS;
 298
 299 error:
 300     Close (obj);
 301     return VLC_EGENERIC;
 302 }
 303
 304
 305 /**
 306  * Releases resources
 307  */
 308 static void Close (vlc_object_t *obj)
 309 {
 310     demux_t *demux = (demux_t *)obj;
 311     demux_sys_t *p_sys = demux->p_sys;
 312
 313     if (p_sys->thread_ready)
 314     {
 315         vlc_cancel (p_sys->thread);
 316         vlc_join (p_sys->thread, NULL);
 317     }
 318     vlc_mutex_destroy (&p_sys->lock);
 319
 320 #ifdef HAVE_SRTP
 321     if (p_sys->srtp)
 322         srtp_destroy (p_sys->srtp);
 323 #endif
 324     if (p_sys->session)
 325         rtp_session_destroy (demux, p_sys->session);
 326     if (p_sys->rtcp_fd != -1)
 327         net_Close (p_sys->rtcp_fd);
 328     net_Close (p_sys->fd);
 329     free (p_sys);
 330 }
 331
 332
 333 /**
 334  * Extracts port number from "[host]:port" or "host:port" strings,
 335  * and remove brackets from the host name.
 336  * @param phost pointer to the string upon entry,
 337  * pointer to the hostname upon return.
 338  * @return port number, 0 if missing.
 339  */
 340 static int extract_port (char **phost)
 341 {
 342     char *host = *phost, *port;
 343
 344     if (host[0] == '[')
 345     {
 346         host = ++*phost; /* skip '[' */
 347         port = strchr (host, ']');
 348         if (port)
 349             *port++ = '\0'; /* skip ']' */
 350     }
 351     else
 352         port = strchr (host, ':');
 353
 354     if (port == NULL)
 355         return 0;
 356     *port++ = '\0'; /* skip ':' */
 357     return atoi (port);
 358 }
 359
 360
 361 /**
 362  * Control callback
 363  */
 364 static int Control (demux_t *demux, int i_query, va_list args)
 365 {
 366     demux_sys_t *p_sys = demux->p_sys;
 367
 368     switch (i_query)
 369     {
 370         case DEMUX_GET_POSITION:
 371         {
 372             float *v = va_arg (args, float *);
 373             *v = 0.;
 374             return VLC_SUCCESS;
 375         }
 376
 377         case DEMUX_GET_LENGTH:
 378         case DEMUX_GET_TIME:
 379         {
 380             int64_t *v = va_arg (args, int64_t *);
 381             *v = 0;
 382             return VLC_SUCCESS;
 383         }
 384
 385         case DEMUX_GET_PTS_DELAY:
 386         {
 387             int64_t *v = va_arg (args, int64_t *);
 388             *v = (int64_t)p_sys->caching * 1000;
 389             return VLC_SUCCESS;
 390         }
 391
 392         case DEMUX_CAN_PAUSE:
 393         case DEMUX_CAN_SEEK:
 394         case DEMUX_CAN_CONTROL_PACE:
 395         {
 396             bool *v = (bool*)va_arg( args, bool * );
 397             *v = false;
 398             return VLC_SUCCESS;
 399         }
 400     }
 401
 402     return VLC_EGENERIC;
 403 }
 404
 405
 406 /*
 407  * Generic packet handlers
 408  */
 409
 410 static void *codec_init (demux_t *demux, es_format_t *fmt)
 411 {
 412     return es_out_Add (demux->out, fmt);
 413 }
 414
 415 static void codec_destroy (demux_t *demux, void *data)
 416 {
 417     if (data)
 418         es_out_Del (demux->out, (es_out_id_t *)data);
 419 }
 420
 421 /* Send a packet to decoder */
 422 static void codec_decode (demux_t *demux, void *data, block_t *block)
 423 {
 424     if (data)
 425     {
 426         block->i_dts = 0; /* RTP does not specify this */
 427         es_out_Control (demux->out, ES_OUT_SET_PCR, block->i_pts );
 428         es_out_Send (demux->out, (es_out_id_t *)data, block);
 429     }
 430     else
 431         block_Release (block);
 432 }
 433
 434 static void *stream_init (demux_t *demux, const char *name)
 435 {
 436     return stream_DemuxNew (demux, name, demux->out);
 437 }
 438
 439 static void stream_destroy (demux_t *demux, void *data)
 440 {
 441     if (data)
 442         stream_Delete ((stream_t *)data);
 443     (void)demux;
 444 }
 445
 446 /* Send a packet to a chained demuxer */
 447 static void stream_decode (demux_t *demux, void *data, block_t *block)
 448 {
 449     if (data)
 450         stream_DemuxSend ((stream_t *)data, block);
 451     else
 452         block_Release (block);
 453     (void)demux;
 454 }
 455
 456 static void *demux_init (demux_t *demux)
 457 {
 458     return stream_init (demux, demux->psz_demux);
 459 }
 460
 461 /*
 462  * Static payload types handler
 463  */
 464
 465 /* PT=0
 466  * PCMU: G.711 µ-law (RFC3551)
 467  */
 468 static void *pcmu_init (demux_t *demux)
 469 {
 470     es_format_t fmt;
 471
 472     es_format_Init (&fmt, AUDIO_ES, VLC_CODEC_MULAW);
 473     fmt.audio.i_rate = 8000;
 474     fmt.audio.i_channels = 1;
 475     return codec_init (demux, &fmt);
 476 }
 477
 478 /* PT=3
 479  * GSM
 480  */
 481 static void *gsm_init (demux_t *demux)
 482 {
 483     es_format_t fmt;
 484
 485     es_format_Init (&fmt, AUDIO_ES, VLC_CODEC_GSM);
 486     fmt.audio.i_rate = 8000;
 487     fmt.audio.i_channels = 1;
 488     return codec_init (demux, &fmt);
 489 }
 490
 491 /* PT=8
 492  * PCMA: G.711 A-law (RFC3551)
 493  */
 494 static void *pcma_init (demux_t *demux)
 495 {
 496     es_format_t fmt;
 497
 498     es_format_Init (&fmt, AUDIO_ES, VLC_CODEC_ALAW);
 499     fmt.audio.i_rate = 8000;
 500     fmt.audio.i_channels = 1;
 501     return codec_init (demux, &fmt);
 502 }
 503
 504 /* PT=10,11
 505  * L16: 16-bits (network byte order) PCM
 506  */
 507 static void *l16s_init (demux_t *demux)
 508 {
 509     es_format_t fmt;
 510
 511     es_format_Init (&fmt, AUDIO_ES, VLC_CODEC_S16B);
 512     fmt.audio.i_rate = 44100;
 513     fmt.audio.i_channels = 2;
 514     return codec_init (demux, &fmt);
 515 }
 516
 517 static void *l16m_init (demux_t *demux)
 518 {
 519     es_format_t fmt;
 520
 521     es_format_Init (&fmt, AUDIO_ES, VLC_CODEC_S16B);
 522     fmt.audio.i_rate = 44100;
 523     fmt.audio.i_channels = 1;
 524     return codec_init (demux, &fmt);
 525 }
 526
 527 /* PT=12
 528  * QCELP
 529  */
 530 static void *qcelp_init (demux_t *demux)
 531 {
 532     es_format_t fmt;
 533
 534     es_format_Init (&fmt, AUDIO_ES, VLC_CODEC_QCELP);
 535     fmt.audio.i_rate = 8000;
 536     fmt.audio.i_channels = 1;
 537     return codec_init (demux, &fmt);
 538 }
 539
 540 /* PT=14
 541  * MPA: MPEG Audio (RFC2250, §3.4)
 542  */
 543 static void *mpa_init (demux_t *demux)
 544 {
 545     es_format_t fmt;
 546
 547     es_format_Init (&fmt, AUDIO_ES, VLC_CODEC_MPGA);
 548     fmt.audio.i_channels = 2;
 549     fmt.b_packetized = false;
 550     return codec_init (demux, &fmt);
 551 }
 552
 553 static void mpa_decode (demux_t *demux, void *data, block_t *block)
 554 {
 555     if (block->i_buffer < 4)
 556     {
 557         block_Release (block);
 558         return;
 559     }
 560
 561     block->i_buffer -= 4; /* 32-bits RTP/MPA header */
 562     block->p_buffer += 4;
 563
 564     codec_decode (demux, data, block);
 565 }
 566
 567
 568 /* PT=32
 569  * MPV: MPEG Video (RFC2250, §3.5)
 570  */
 571 static void *mpv_init (demux_t *demux)
 572 {
 573     es_format_t fmt;
 574
 575     es_format_Init (&fmt, VIDEO_ES, VLC_CODEC_MPGV);
 576     fmt.b_packetized = false;
 577     return codec_init (demux, &fmt);
 578 }
 579
 580 static void mpv_decode (demux_t *demux, void *data, block_t *block)
 581 {
 582     if (block->i_buffer < 4)
 583     {
 584         block_Release (block);
 585         return;
 586     }
 587
 588     block->i_buffer -= 4; /* 32-bits RTP/MPV header */
 589     block->p_buffer += 4;
 590 #if 0
 591     if (block->p_buffer[-3] & 0x4)
 592     {
 593         /* MPEG2 Video extension header */
 594         /* TODO: shouldn't we skip this too ? */
 595     }
 596 #endif
 597     codec_decode (demux, data, block);
 598 }
 599
 600
 601 /* PT=33
 602  * MP2: MPEG TS (RFC2250, §2)
 603  */
 604 static void *ts_init (demux_t *demux)
 605 {
 606     return stream_init (demux, *demux->psz_demux ? demux->psz_demux : "ts");
 607 }
 608
 609
 610 /* Not using SDP, we need to guess the payload format used */
 611 /* see http://www.iana.org/assignments/rtp-parameters */
 612 int rtp_autodetect (demux_t *demux, rtp_session_t *session,
 613                     const block_t *block)
 614 {
 615     uint8_t ptype = rtp_ptype (block);
 616     rtp_pt_t pt = {
 617         .init = NULL,
 618         .destroy = codec_destroy,
 619         .decode = codec_decode,
 620         .frequency = 0,
 621         .number = ptype,
 622     };
 623
 624     /* Remember to keep this in sync with modules/services_discovery/sap.c */
 625     switch (ptype)
 626     {
 627       case 0:
 628         msg_Dbg (demux, "detected G.711 mu-law");
 629         pt.init = pcmu_init;
 630         pt.frequency = 8000;
 631         break;
 632
 633       case 3:
 634         msg_Dbg (demux, "detected GSM");
 635         pt.init = gsm_init;
 636         pt.frequency = 8000;
 637         break;
 638
 639       case 8:
 640         msg_Dbg (demux, "detected G.711 A-law");
 641         pt.init = pcma_init;
 642         pt.frequency = 8000;
 643         break;
 644
 645       case 10:
 646         msg_Dbg (demux, "detected stereo PCM");
 647         pt.init = l16s_init;
 648         pt.frequency = 44100;
 649         break;
 650
 651       case 11:
 652         msg_Dbg (demux, "detected mono PCM");
 653         pt.init = l16m_init;
 654         pt.frequency = 44100;
 655         break;
 656
 657       case 12:
 658         msg_Dbg (demux, "detected QCELP");
 659         pt.init = qcelp_init;
 660         pt.frequency = 8000;
 661         break;
 662
 663       case 14:
 664         msg_Dbg (demux, "detected MPEG Audio");
 665         pt.init = mpa_init;
 666         pt.decode = mpa_decode;
 667         pt.frequency = 90000;
 668         break;
 669
 670       case 32:
 671         msg_Dbg (demux, "detected MPEG Video");
 672         pt.init = mpv_init;
 673         pt.decode = mpv_decode;
 674         pt.frequency = 90000;
 675         break;
 676
 677       case 33:
 678         msg_Dbg (demux, "detected MPEG2 TS");
 679         pt.init = ts_init;
 680         pt.destroy = stream_destroy;
 681         pt.decode = stream_decode;
 682         pt.frequency = 90000;
 683         break;
 684
 685       default:
 686         /*
 687          * If the rtp payload type is unknown then check demux if it is specified
 688          */
 689         if ((strcmp(demux->psz_demux, "h264") == 0) || (strcmp(demux->psz_demux, "ts") == 0))
 690         {
 691           msg_Dbg (demux, "rtp autodetect specified demux=%s", demux->psz_demux);
 692           pt.init = demux_init;
 693           pt.destroy = stream_destroy;
 694           pt.decode = stream_decode;
 695           pt.frequency = 90000;
 696           break;
 697         }
 698         else
 699         {
 700           return -1;
 701         }
 702     }
 703     rtp_add_type (demux, session, &pt);
 704     return 0;
 705 }
 706
 707 /*
 708  * Dynamic payload type handlers
 709  * Hmm, none implemented yet.
 710  */