rtp.h

IP网络语音通讯软件源代码. 不可多得的语音源代码

/*
* rtp.h  --  RTP header file
* RTP draft: November 1994 version
*
* $Id: RTP.H,v 1.1.1.1 1998/10/15 00:47:32 Administrator 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