http://blog.csdn.net/wangjiannuaa/article/details/6694831#
H264.h头文件内容：
#include <stdio.h>
#include <stdlib.h>
#include <conio.h>
#include <string.h>
#include <winsock2.h>
#pragma comment( lib, "ws2_32.lib" )
#define PACKET_BUFFER_END (unsigned int)0x00000000
#define MAX_RTP_PKT_LENGTH 1400
#define DEST_IP "192.168.0.25"
#define DEST_PORT 1234
#define H264 96
/******************************************************************
RTP_FIXED_HEADER
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|V=2|P|X| CC |M| PT | sequence number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| timestamp |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| synchronization source (SSRC) identifier |
+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
| contributing source (CSRC) identifiers |
| .... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
******************************************************************/
typedef struct
{
/* byte 0 */
unsigned char csrc_len:4; /* CC expect 0 */
unsigned char extension:1;/* X expect 1, see RTP_OP below */
unsigned char padding:1; /* P expect 0 */
unsigned char version:2; /* V expect 2 */
/* byte 1 */
unsigned char payload:7; /* PT RTP_PAYLOAD_RTSP */
unsigned char marker:1; /* M expect 1 */
/* byte 2,3 */
unsigned short seq_no; /*sequence number*/
/* byte 4-7 */
unsigned long timestamp;
/* byte 8-11 */
unsigned long ssrc; /* stream number is used here. */
} RTP_FIXED_HEADER;/*12 bytes*/
/******************************************************************
NALU_HEADER
+---------------+
|0|1|2|3|4|5|6|7|
+-+-+-+-+-+-+-+-+
|F|NRI| Type |
+---------------+
******************************************************************/
typedef struct {
//byte 0
unsigned char TYPE:5;
unsigned char NRI:2;
unsigned char F:1;
} NALU_HEADER; /* 1 byte */
/******************************************************************
FU_INDICATOR
+---------------+
|0|1|2|3|4|5|6|7|
+-+-+-+-+-+-+-+-+
|F|NRI| Type |
+---------------+
******************************************************************/
typedef struct {
//byte 0
unsigned char TYPE:5;
unsigned char NRI:2;
unsigned char F:1;
} FU_INDICATOR; /*1 byte */
/******************************************************************
FU_HEADER
+---------------+
|0|1|2|3|4|5|6|7|
+-+-+-+-+-+-+-+-+
|S|E|R| Type |
+---------------+
******************************************************************/
typedef struct {
//byte 0
unsigned char TYPE:5;
unsigned char R:1;
unsigned char E:1;
unsigned char S:1;
} FU_HEADER; /* 1 byte */
RTPSend.cpp文件内容：
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <memory.h>
#include "h264.h"
#define UDP_MAX_SIZE 1400
typedef struct
{
int startcodeprefix_len; //! 4 for parameter sets and first slice in picture, 3 for everything else (suggested)
unsigned len; //! Length of the NAL unit (Excluding the start code, which does not belong to the NALU)
unsigned max_size; //! Nal Unit Buffer size
int forbidden_bit; //! should be always FALSE
int nal_reference_idc; //! NALU_PRIORITY_xxxx
int nal_unit_type; //! NALU_TYPE_xxxx
char *buf; //! contains the first byte followed by the EBSP
unsigned short lost_packets; //! true, if packet loss is detected
} NALU_t;
FILE *bits = NULL; //!< the bit stream file
static int FindStartCode2(unsigned char *Buf);//查找开始字符0x000001
static int FindStartCode3(unsigned char *Buf);//查找开始字符0x00000001
static int info2=0, info3=0;
RTP_FIXED_HEADER *rtp_hdr;
NALU_HEADER *nalu_hdr;
FU_INDICATOR *fu_ind;
FU_HEADER *fu_hdr;
BOOL InitWinsock()
{
int Error;
WORD VersionRequested;
WSADATA WsaData;
VersionRequested=MAKEWORD(2,2);
Error=WSAStartup(VersionRequested,&WsaData); //启动WinSock2
if(Error!=0)
{
return FALSE;
}
else
{
if(LOBYTE(WsaData.wVersion)!=2||HIBYTE(WsaData.wHighVersion)!=2)
{
WSACleanup();
return FALSE;
}
}
return TRUE;
}
//为NALU_t结构体分配内存空间
NALU_t *AllocNALU(int buffersize)
{
NALU_t *n;
if ((n = (NALU_t*)calloc (1, sizeof (NALU_t))) == NULL)
{
printf("AllocNALU: n");
exit(0);
}
n->max_size=buffersize;
if ((n->buf = (char*)calloc (buffersize, sizeof (char))) == NULL)
{
free (n);
printf ("AllocNALU: n->buf");
exit(0);
}
return n;
}
//释放
void FreeNALU(NALU_t *n)
{
if (n)
{
if (n->buf)
{
free(n->buf);
n->buf=NULL;
}
free (n);
}
}
void OpenBitstreamFile (char *fn)
{
if (NULL == (bits=fopen(fn, "rb")))
{
printf("open file error\n");
exit(0);
}
}
//这个函数输入为一个NAL结构体，主要功能为得到一个完整的NALU并保存在NALU_t的buf中，
//获取他的长度，填充F,IDC,TYPE位。
//并且返回两个开始字符之间间隔的字节数，即包含有前缀的NALU的长度
int GetAnnexbNALU (NALU_t *nalu)
{
int pos = 0;
int StartCodeFound, rewind;
unsigned char *Buf;
if ((Buf = (unsigned char*)calloc (nalu->max_size , sizeof(char))) == NULL)
printf ("GetAnnexbNALU: Could not allocate Buf memory\n");
nalu->startcodeprefix_len=3;//初始化码流序列的开始字符为3个字节
if (3 != fread (Buf, 1, 3, bits))//从码流中读3个字节
{
free(Buf);
return 0;
}
info2 = FindStartCode2 (Buf);//判断是否为0x000001
if(info2 != 1)
{
//如果不是，再读一个字节
if(1 != fread(Buf+3, 1, 1, bits))//读一个字节
{
free(Buf);
return 0;
}
info3 = FindStartCode3 (Buf);//判断是否为0x00000001
if (info3 != 1)//如果不是，返回-1
{
free(Buf);
return -1;
}
else
{
//如果是0x00000001,得到开始前缀为4个字节
pos = 4;
nalu->startcodeprefix_len = 4;
}
}
else
{
//如果是0x000001,得到开始前缀为3个字节
nalu->startcodeprefix_len = 3;
pos = 3;
}
//查找下一个开始字符的标志位
StartCodeFound = 0;
info2 = 0;
info3 = 0;
while (!StartCodeFound)
{
if (feof (bits))//判断是否到了文件尾
{
nalu->len = (pos-1)-nalu->startcodeprefix_len;
memcpy (nalu->buf, &Buf[nalu->startcodeprefix_len], nalu->len);
nalu->forbidden_bit = nalu->buf[0] & 0x80; //1 bit
nalu->nal_reference_idc = nalu->buf[0] & 0x60; // 2 bit
nalu->nal_unit_type = (nalu->buf[0]) & 0x1f;// 5 bit
free(Buf);
return pos-1;
}
Buf[pos++] = fgetc (bits);//读一个字节到BUF中
info3 = FindStartCode3(&Buf[pos-4]);//判断是否为0x00000001
if(info3 != 1)
info2 = FindStartCode2(&Buf[pos-3]);//判断是否为0x000001
StartCodeFound = (info2 == 1 || info3 == 1);
}
// Here, we have found another start code (and read length of startcode bytes more than we should
// have. Hence, go back in the file
rewind = (info3 == 1)? -4 : -3;
if (0 != fseek (bits, rewind, SEEK_CUR))//把文件指针指向前一个NALU的末尾
{
free(Buf);
printf("GetAnnexbNALU: Cannot fseek in the bit stream file");
}
// Here the Start code, the complete NALU, and the next start code is in the Buf.
// The size of Buf is pos, pos+rewind are the number of bytes excluding the next
// start code, and (pos+rewind)-startcodeprefix_len is the size of the NALU excluding the start code
nalu->len = (pos+rewind)-nalu->startcodeprefix_len;
memcpy (nalu->buf, &Buf[nalu->startcodeprefix_len], nalu->len);//拷贝一个完整NALU，不拷贝起始前缀0x000001或0x00000001
nalu->forbidden_bit = nalu->buf[0] & 0x80; //1 bit
nalu->nal_reference_idc = nalu->buf[0] & 0x60; //2 bit
nalu->nal_unit_type = (nalu->buf[0]) & 0x1f; //5 bit
free(Buf);
return (pos+rewind);//返回两个开始字符之间间隔的字节数，即包含有前缀的NALU的长度
}
static int FindStartCode2 (unsigned char *Buf)
{
if(Buf[0]!=0 || Buf[1]!=0 || Buf[2] !=1) return 0; //判断是否为0x000001,如果是返回1
else return 1;
}
static int FindStartCode3 (unsigned char *Buf)
{
if(Buf[0]!=0 || Buf[1]!=0 || Buf[2] !=0 || Buf[3] !=1) return 0;//判断是否为0x00000001,如果是返回1
else return 1;
}
int rtpnum = 0;
//输出NALU长度和TYPE
void dump(NALU_t *n)
{
if (!n)return;
printf("%3d, len: %6d ",rtpnum++, n->len);
printf("nal_unit_type: %x\n", n->nal_unit_type);
}
int main(int argc, char* argv[])
{
OpenBitstreamFile("E:\\测试数据\\tv480x320.264");
NALU_t *n;
char* nalu_payload;
char sendbuf[1500];
unsigned short seq_num =0;
int bytes=0;
InitWinsock(); //初始化套接字库
SOCKET socket1;
struct sockaddr_in server;
int len =sizeof(server);
float framerate=15;
unsigned int timestamp_increse=0,ts_current=0;
timestamp_increse=(unsigned int)(90000.0 / framerate); //+0.5);
server.sin_family=AF_INET;
server.sin_port=htons(DEST_PORT);
server.sin_addr.s_addr=inet_addr(DEST_IP);
socket1=socket(AF_INET,SOCK_DGRAM,0);
connect(socket1, (const sockaddr *)&server, len) ;//申请UDP套接字
n = AllocNALU(8000000);//为结构体nalu_t及其成员buf分配空间。返回值为指向nalu_t存储空间的指针
while(!feof(bits))
{
GetAnnexbNALU(n);//每执行一次，文件的指针指向本次找到的NALU的末尾，下一个位置即为下个NALU的起始码0x000001
dump(n);//输出NALU长度和TYPE
memset(sendbuf,0,1500);//清空sendbuf；此时会将上次的时间戳清空，因此需要ts_current来保存上次的时间戳值
//rtp固定包头，为12字节,该句将sendbuf[0]的地址赋给rtp_hdr，以后对rtp_hdr的写入操作将直接写入sendbuf。
rtp_hdr =(RTP_FIXED_HEADER*)&sendbuf[0];
//设置RTP HEADER，
rtp_hdr->version = 2; //版本号，此版本固定为2
rtp_hdr->marker = 0; //标志位，由具体协议规定其值。
rtp_hdr->payload = H264;//负载类型号，
rtp_hdr->ssrc = htonl(10);//随机指定为10，并且在本RTP会话中全局唯一
//当一个NALU小于1400字节的时候，采用一个单RTP包发送
if(n->len<=UDP_MAX_SIZE){
//设置rtp M 位；
rtp_hdr->marker=1;
rtp_hdr->seq_no = htons(seq_num ++); //序列号，每发送一个RTP包增1
//设置NALU HEADER,并将这个HEADER填入sendbuf[12]
nalu_hdr =(NALU_HEADER*)&sendbuf[12]; //将sendbuf[12]的地址赋给nalu_hdr，之后对nalu_hdr的写入就将写入sendbuf中；
nalu_hdr->F=n->forbidden_bit;
nalu_hdr->NRI=n->nal_reference_idc>>5;//有效数据在n->nal_reference_idc的第6，7位，需要右移5位才能将其值赋给nalu_hdr->NRI。
nalu_hdr->TYPE=n->nal_unit_type;
nalu_payload=&sendbuf[13];//同理将sendbuf[13]赋给nalu_payload
memcpy(nalu_payload,n->buf+1,n->len-1);//去掉nalu头的nalu剩余内容写入sendbuf[13]开始的字符串。
ts_current=ts_current+timestamp_increse;
rtp_hdr->timestamp=htonl(ts_current);
bytes=n->len + 12 ; //获得sendbuf的长度,为nalu的长度（包含NALU头但除去起始前缀）加上rtp_header的固定长度12字节
send(socket1,sendbuf,bytes,0);//发送RTP包
//Sleep(100);
}else{
int packetNum = n->len/UDP_MAX_SIZE;
if (n->len%UDP_MAX_SIZE != 0)
packetNum ++;
int lastPackSize = n->len - (packetNum-1)*UDP_MAX_SIZE;
int packetIndex = 1 ;
ts_current=ts_current+timestamp_increse;
rtp_hdr->timestamp=htonl(ts_current);
//发送第一个的FU，S=1，E=0，R=0
rtp_hdr->seq_no = htons(seq_num ++); //序列号，每发送一个RTP包增1
//设置rtp M 位；
rtp_hdr->marker=0;
//设置FU INDICATOR,并将这个HEADER填入sendbuf[12]
fu_ind =(FU_INDICATOR*)&sendbuf[12]; //将sendbuf[12]的地址赋给fu_ind，之后对fu_ind的写入就将写入sendbuf中；
fu_ind->F=n->forbidden_bit;
fu_ind->NRI=n->nal_reference_idc>>5;
fu_ind->TYPE=28;
//设置FU HEADER,并将这个HEADER填入sendbuf[13]
fu_hdr =(FU_HEADER*)&sendbuf[13];
fu_hdr->S=1;
fu_hdr->E=0;
fu_hdr->R=0;
fu_hdr->TYPE=n->nal_unit_type;
nalu_payload=&sendbuf[14];//同理将sendbuf[14]赋给nalu_payload
memcpy(nalu_payload,n->buf+1,UDP_MAX_SIZE);//去掉NALU头
bytes=UDP_MAX_SIZE+14;//获得sendbuf的长度,为nalu的长度（除去起始前缀和NALU头）加上rtp_header，fu_ind，fu_hdr的固定长度14字节
send( socket1, sendbuf, bytes, 0 );//发送RTP包
//发送中间的FU，S=0，E=0，R=0
for(packetIndex=2;packetIndex<packetNum;packetIndex++)
{
rtp_hdr->seq_no = htons(seq_num ++); //序列号，每发送一个RTP包增1
//设置rtp M 位；
rtp_hdr->marker=0;
//设置FU INDICATOR,并将这个HEADER填入sendbuf[12]
fu_ind =(FU_INDICATOR*)&sendbuf[12]; //将sendbuf[12]的地址赋给fu_ind，之后对fu_ind的写入就将写入sendbuf中；
fu_ind->F=n->forbidden_bit;
fu_ind->NRI=n->nal_reference_idc>>5;
fu_ind->TYPE=28;
//设置FU HEADER,并将这个HEADER填入sendbuf[13]
fu_hdr =(FU_HEADER*)&sendbuf[13];
fu_hdr->S=0;
fu_hdr->E=0;
fu_hdr->R=0;
fu_hdr->TYPE=n->nal_unit_type;
nalu_payload=&sendbuf[14];//同理将sendbuf[14]的地址赋给nalu_payload
memcpy(nalu_payload,n->buf+(packetIndex-1)*UDP_MAX_SIZE+1,UDP_MAX_SIZE);//去掉起始前缀的nalu剩余内容写入sendbuf[14]开始的字符串。
bytes=UDP_MAX_SIZE+14;//获得sendbuf的长度,为nalu的长度（除去原NALU头）加上rtp_header，fu_ind，fu_hdr的固定长度14字节
send( socket1, sendbuf, bytes, 0 );//发送rtp包
}
//发送最后一个的FU，S=0，E=1，R=0
rtp_hdr->seq_no = htons(seq_num ++);
//设置rtp M 位；当前传输的是最后一个分片时该位置1
rtp_hdr->marker=1;
//设置FU INDICATOR,并将这个HEADER填入sendbuf[12]
fu_ind =(FU_INDICATOR*)&sendbuf[12]; //将sendbuf[12]的地址赋给fu_ind，之后对fu_ind的写入就将写入sendbuf中；
fu_ind->F=n->forbidden_bit;
fu_ind->NRI=n->nal_reference_idc>>5;
fu_ind->TYPE=28;
//设置FU HEADER,并将这个HEADER填入sendbuf[13]
fu_hdr =(FU_HEADER*)&sendbuf[13];
fu_hdr->S=0;
fu_hdr->E=1;
fu_hdr->R=0;
fu_hdr->TYPE=n->nal_unit_type;
nalu_payload=&sendbuf[14];//同理将sendbuf[14]的地址赋给nalu_payload
memcpy(nalu_payload,n->buf+(packetIndex-1)*UDP_MAX_SIZE+1,lastPackSize-1);//将nalu最后剩余的-1(去掉了一个字节的NALU头)字节内容写入sendbuf[14]开始的字符串。
bytes=lastPackSize-1+14;//获得sendbuf的长度,为剩余nalu的长度l-1加上rtp_header，FU_INDICATOR,FU_HEADER三个包头共14字节
send( socket1, sendbuf, bytes, 0 );//发送rtp包
}
//Sleep(33);
}
FreeNALU(n);
return 0;
}
将以下文本保存为rtpPara.sdp文件
m=video 1234 RTP/AVP 96
a=rtpmap:96 H264
a=framerate:30
c=IN IP4 192.168.0.25
用VLC打开该文件，然后运行编译好的发送程序。
注意头文件和sdp文件的IP都要与实验机器的IP吻合。
该代码在NALDecoder程序基础上修改了一个内存bug而已。感谢前人的开源。