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rtp.h

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/*
* rtp.h  --  RTP header file
* RTP draft: November 1994 version
*
* $Id: rtp.h,v 1.1.1.1 2003/02/04 22:30:34 johnwalker Exp $
*/

#ifdef MICROSOFT_COMPILERS_CAN_BE_TRUSTED
#error Microsoft compilers can *never* be trusted,
#error except to invariably do the wrong thing.
typedef unsigned char u_int8;
typedef unsigned short u_int16;
typedef unsigned long u_int32;
#endif

#define RTP_SEQ_MOD (1<<16)
#define RTP_TS_MOD      (0xffffffff)
/*
* Current type value.
*/
#define RTP_VERSION 2

#define RTP_MAX_SDES 256   /* maximum text length for SDES */

typedef enum {
  RTCP_SR       = 200,
  RTCP_RR       = 201,
  RTCP_SDES = 202,
  RTCP_BYE      = 203,
  RTCP_APP      = 204
} rtcp_type_t;

typedef enum {
  RTCP_SDES_END    =  0,
  RTCP_SDES_CNAME  =  1,
  RTCP_SDES_NAME   =  2,
  RTCP_SDES_EMAIL  =  3,
  RTCP_SDES_PHONE  =  4,
  RTCP_SDES_LOC    =  5,
  RTCP_SDES_TOOL   =  6,
  RTCP_SDES_NOTE   =  7,
  RTCP_SDES_PRIV   =  8, 
  RTCP_SDES_IMG    =  9,
  RTCP_SDES_DOOR   = 10,
  RTCP_SDES_SOURCE = 11
} rtcp_sdes_type_t;

#ifdef MICROSOFT_COMPILERS_CAN_BE_TRUSTED

/*      We don't dare use the following structures, which appear
        for documentation only, because Microsoft Visual C has
        incompatible and downright weird ideas about packing bit
        fields and structures.  The packets are actually processed
        using hard-coded byte numbers and shifting for the bit
        fields to guarantee the compiler can't inject its own
        opinions into the process.  */

typedef struct {
  unsigned int version:2;  /* protocol version */
  unsigned int p:1;        /* padding flag */
  unsigned int x:1;        /* header extension flag */
  unsigned int cc:4;       /* CSRC count */
  unsigned int m:1;        /* marker bit */
  unsigned int pt:7;       /* payload type */
  u_int16 seq;                     /* sequence number */
  u_int32 ts;                      /* timestamp */
  u_int32 ssrc;                    /* synchronization source */
  u_int32 csrc[1];                 /* optional CSRC list */
} rtp_hdr_t;

typedef struct {
  unsigned int version:2;  /* protocol version */
  unsigned int p:1;        /* padding flag */
  unsigned int count:5;    /* varies by payload type */
  unsigned int pt:8;       /* payload type */
  u_int16 length;                  /* packet length in words, without this word */
} rtcp_common_t;

/* reception report */
typedef struct {
  u_int32 ssrc;                    /* data source being reported */
  unsigned long fraction:8; /* fraction lost since last SR/RR */
  long lost:24;                    /* cumulative number of packets lost (signed!) */
  u_int32 last_seq;        /* extended last sequence number received */
  u_int32 jitter;                  /* interarrival jitter */
  u_int32 lsr;                     /* last SR packet from this source */
  u_int32 dlsr;                    /* delay since last SR packet */
} rtcp_rr_t;

typedef struct {
  u_int8 type;                     /* type of SDES item (rtcp_sdes_type_t) */
  u_int8 length;                   /* length of SDES item (in octets) */
  char data[1];                    /* text, not zero-terminated */
} rtcp_sdes_item_t;

/* one RTCP packet */
typedef struct {
  rtcp_common_t common;    /* common header */
  union {
        /* sender report (SR) */
        struct {
          u_int32 ssrc;            /* source this RTCP packet refers to */
          u_int32 ntp_sec;         /* NTP timestamp */
          u_int32 ntp_frac;
          u_int32 rtp_ts;          /* RTP timestamp */
          u_int32 psent;           /* packets sent */
          u_int32 osent;           /* octets sent */ 
          /* variable-length list */
          rtcp_rr_t rr[1];
        } sr;

        /* reception report (RR) */
        struct {
          u_int32 ssrc;            /* source this generating this report */
          /* variable-length list */
          rtcp_rr_t rr[1];
        } rr;

        /* BYE */
        struct {
          u_int32 src[1];          /* list of sources */
      /* can't express trailing text */
        } bye;

        /* source description (SDES) */
        struct rtcp_sdes_t {
          u_int32 src;                          /* first SSRC/CSRC */
          rtcp_sdes_item_t item[1]; /* list of SDES items */
        } sdes;
  } r;
} rtcp_t;
#endif

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