rtp 报头的大小端 可查看jrtplib 中的定义

#ifdef __HI_CODEC__ 

#else
#define WORDS_BIGENDIAN  
#endif
typedef struct rtp_packet_header {
#ifdef WORDS_BIGENDIAN
unsigned short   ph_v:2; /* packet type                */
unsigned short   ph_p:1; /* padding flag               */
unsigned short   ph_x:1; /* header extension flag      */
unsigned short   ph_cc:4; /* CSRC count                 */
unsigned short   ph_m:1; /* marker bit                 */
unsigned short   ph_pt:7; /* payload type               */
#else
unsigned short   ph_cc:4; /* CSRC count                 */
unsigned short   ph_x:1; /* header extension flag      */
unsigned short   ph_p:1; /* padding flag               */
unsigned short   ph_v:2; /* packet type                */
unsigned short   ph_pt:7; /* payload type               */
unsigned short   ph_m:1; /* marker bit                 */
#endif
uint16_t          ph_seq; /* sequence number            */
uint32_t          ph_ts; /* timestamp                  */
uint32_t          ph_ssrc; /* synchronization source     */
/* The csrc list, header extension and data follow, but can't */
/* be represented in the struct.                              */

} rtp_packet_header;

小端模式高位在低地址； 大端低地址低位高地址高位