RTP/RTCP (real-time transport protocol/real-time Transmission Control Protocol) custom related C structure (reference)

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Rtp/rtcp (real-time transport protocol/real-time Transport Control Protocol) is based on UDP-derived protocols and adds control over real-time transmission. Commonly used for online transmission of real-time video data, such as remote video surveillance, video-on-demand. There is a book called "Multimedia Network Transmission Protocol" on the structure and principle of the 2 agreements to do a more detailed introduction, as if it was published by Tsinghua University Press.
     last year when I was a remote video surveillance system, I used the Wonsock tool to encapsulate a network transport dynamic connection library, which was designed for the real-time video data of LAN multicast, based on 2 protocols. Here are the related C structures I defined for this 2 protocol.
    /*current protocol version. */
#define  RTP_VERSION     2
#define  MIN_SEQUENTIAL  1
#define  RTP_SEQ_MOD  (1<<16)
#define  RTP_MAX_SDES 255      /* maximum text  length for sdes */
#define &NBSP;MID_BUFFER_NUM&NBSP;&NBSP;&NBSP;2
#define  max_ Dropout   25

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_type_t;

/*
* RTP Data Header
*/
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;

/*
 * rtcp common header word
 */
typedef struct {
   unsigned int version:2;   /* protocol version */
   unsigned int p:1;         /*  padding flag */
   unsigned int count:5;     /*  varies by packet type */
   unsigned int pt:8;         /* rtcp packet type */
   u_ int16 length;           /* pkt len  in words, w/o this word */
} rtcp_common_t;

/*
* Big-endian mask for version, padding bit and packet type pair
*/
#define RTCP_VALID_MASK (0xc000 | 0x2000 | 0xfe)
#define Rtcp_valid_value ((rtp_version << 14) | RTCP_SR)

/*
* Reception Report block
*/
typedef struct {
U_int32 SSRC; /* Data source being reported */
unsigned int fraction:8; /* Fraction lost since last SR/RR */
int lost:24; /* Cumul. No. Pkts Lost (signed!) */
U_int32 Last_seq; /* Extended last seq. No. 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;

/*
* SDEs Item
*/
typedef struct {
U_int8 type; /* Type of item (rtcp_sdes_type_t) */
U_int8 length; /* Length of item (in octets) */
Char data[1]; /* text, not null-terminated */
} rtcp_sdes_item_t;

/*
* One RTCP packet
*/
typedef struct {
Rtcp_common_t Common; /* Common Header */
Union {
/* Sender report (SR) */
struct {
U_int32 SSRC; /* Sender Generating this report */
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 */
rtcp_rr_t Rr[1]; /* Variable-length list */
} SR;

       /* reception report  (RR)  */
        struct {
          u_ int32 ssrc;     /* receiver generating this report */
          rtcp_rr_t rr[1];  /*  variable-length list */
       } rr;

       /* source description  (sdes)  */
        struct rtcp_sdes {
           u_int32 src;      /* first ssrc/csrc */
          rtcp_sdes_item_t item[1]; /*  list of sdes items */
       } sdes;

       /* bye */
        struct {
          u_int32 src[1];    /* list of sources */
                            /*  can ' t express trailing text for reason */
        } bye;
   } r;
} rtcp_t;   &NBSP;