Encapsulation: An encapsulation of RTP packets may be defined to
allow multiple RTP data packets to be carried in one lower-layer
packet or to provide framing over underlying protocols that do
not already do so (Section 10).
Schulzrinne, et al Standards Track [Page 54]
RFC 1889 RTP January 1996
It is not expected that a new profile will be required for every
application. Within one application class, it would be better to
extend an existing profile rather than make a new one in order to
facilitate interoperation among the applications since each will
typically run under only one profile. Simple extensions such as the
definition of additional payload type values or RTCP packet types may
be accomplished by registering them through the Internet Assigned
Numbers Authority and publishing their descriptions in an addendum to
the profile or in a payload format specification.
Schulzrinne, et al Standards Track [Page 55]
RFC 1889 RTP January 1996
A. Algorithms
We provide examples of C code for aspects of RTP sender and receiver
algorithms. There may be other implementation methods that are faster
in particular operating environments or have other advantages. These
implementation notes are for informational purposes only and are
meant to clarify the RTP specification.
The following definitions are used for all examples; for clarity and
brevity, the structure definitions are only valid for 32-bit big-
endian (most significant octet first) architectures. Bit fields are
assumed to be packed tightly in big-endian bit order, with no
additional padding. Modifications would be required to construct a
portable implementation.
/*
* rtp.h -- RTP header file (RFC XXXX)
*/
#include <sys/types.h>
/*
* The type definitions below are valid for 32-bit architectures and
* may have to be adjusted for 16- or 64-bit architectures.
*/
typedef unsigned char u_int8;
typedef unsigned short u_int16;
typedef unsigned int u_int32;
typedef short int16;
/*
* Current protocol version.
*/
#define RTP_VERSION 2
#define RTP_SEQ_MOD (1<<16)
#define RTP_MAX_SDES 255 /* 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,
