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unpackrtp.c
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unpackrtp.c
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#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "unpackrtp.h"
unsigned char timestamp_no[4];//timestamp
unsigned char seq_no[2]; //序号
int UnpackRTPH264(unsigned char *bufIn,int len,struct packet *avpacket)
{
int outlen=0;
if (len < RTP_HEADLEN) return -1 ;
//rtp头解析
memcpy(timestamp_no,(unsigned char * )bufIn+4,4);
//avpacket->timestamp=(int64_t)((timestamp_no[0]<<24)+((timestamp_no[1]<<16)+(timestamp_no[2]<<8)))+timestamp_no[3];//有错误，出现负数
avpacket->timestamp=(int64_t)(timestamp_no[0]*pow(2,24)+timestamp_no[1]*pow(2,16)+timestamp_no[2]*pow(2,8)+timestamp_no[3]);
memcpy(seq_no,(unsigned char * )bufIn+2,2);
avpacket->seq=(seq_no[0]<<8)+seq_no[1];
//h264playload解析
unsigned char *src = (unsigned char * )bufIn + RTP_HEADLEN;
unsigned char head1 = * src; // 获取第一个字节
unsigned char nal = head1 & 0x1f ; // 获取FU indicator的类型域，
unsigned char head2 = * (src + 1 ); // 获取第二个字节
unsigned char flag = head2 & 0xe0 ; // 获取FU header的前三位，判断当前是分包的开始、中间或结束
unsigned char nal_fua = (head1 & 0xe0 ) | (head2 & 0x1f ); // FU_A nal
avpacket->nal=nal;//输出nal
if (nal == 0x1c ){
if (flag == 0x80 ) // 开始
{
avpacket->outbuffer[0]=0x0;
avpacket->outbuffer[1]=0x0;
avpacket->outbuffer[2]=0x0;
avpacket->outbuffer[3]=0x1;
avpacket->outbuffer[4]=nal_fua;
outlen = len - RTP_HEADLEN -2+5;//-2跳过前2个字节，+5前面前导码和类型码
memcpy(avpacket->outbuffer+5,src+2,outlen);
avpacket->outlen=outlen;
avpacket->flag=flag;//输出flag
//printf("start:bufout[end]=%x %x %x %x,src[end]=%x\n",bufout[outlen-4],bufout[outlen-3],bufout[outlen-2],bufout[outlen-1],src[len-RTP_HEADLEN-1]);
}
else if (flag == 0x40 ) // 结束
{
outlen = len - RTP_HEADLEN -2 ;
memcpy(avpacket->outbuffer,src+2,len-RTP_HEADLEN-2);
avpacket->outlen=outlen;
avpacket->flag=flag;//输出flag
//printf("end:bufout[end]=%x %x %x %x,src[end]=%x\n",bufout[outlen-4],bufout[outlen-3],bufout[outlen-2],bufout[outlen-1],src[len-RTP_HEADLEN-1]);
}
else // 中间
{
outlen = len - RTP_HEADLEN -2 ;
memcpy(avpacket->outbuffer,src+2,len-RTP_HEADLEN-2);
avpacket->outlen=outlen;
avpacket->flag=flag;//输出flag
//printf("center:bufout[end]=%x %x %x %x,src[end]=%x\n",bufout[outlen-4],bufout[outlen-3],bufout[outlen-2],bufout[outlen-1],src[len-RTP_HEADLEN-1]);
}
}
else if (nal == 0x07 )
{//sps
//printf("sps");
avpacket->outbuffer[0]=0x0;
avpacket->outbuffer[1]=0x0;
avpacket->outbuffer[2]=0x0;
avpacket->outbuffer[3]=0x1;
memcpy(avpacket->outbuffer+4,src,len-RTP_HEADLEN);
outlen=len-RTP_HEADLEN+4;
avpacket->outlen=outlen;
}
else {//当个包，1,7,8
//printf("*****");
avpacket->outbuffer[0]=0x0;
avpacket->outbuffer[1]=0x0;
avpacket->outbuffer[2]=0x0;
avpacket->outbuffer[3]=0x1;
memcpy(avpacket->outbuffer+4,src,len-RTP_HEADLEN);
outlen=len-RTP_HEADLEN+4;
avpacket->outlen=outlen;
//printf("singe:bufout[3]=%x %x %x %x,src[0]=%x\n",bufout[3],bufout[4],bufout[5],bufout[6],src[0]);
}
return 0;
}
static char h264prefix[4] = {0x00, 0x00, 0x00, 0x01};
int UnpackRtpSTAP_A_NAL(unsigned char *buf, int size, unsigned char *framebuf)
{
int len = sizeof(h264prefix);
unsigned char *pos = framebuf;
unsigned char *q = NULL;
unsigned int nalu_size;
int paysize = size;
q = buf+1;
int nidx = 0;
int counter=0;
while (nidx < (paysize-1)) {
memcpy((void *)pos, (const void*)(&h264prefix), len);
pos += len;
/* get NALU size */
nalu_size = ((unsigned char)q[nidx]<<8)|((unsigned char)q[nidx+1]);
nidx += 2;
if (nalu_size == 0) {
nidx++;
continue;
}
memcpy((void *)pos, (const void*)(q+nidx), nalu_size);
nidx += nalu_size;
pos += nalu_size;
counter++;
}
return (pos-framebuf);
}