H264.h頭文件內容：
#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文件內容：
#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);//查找開始字符0x000001
static int FindStartCode3(unsigned char *Buf);//查找開始字符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); //啓動WinSock2
if(Error!=0)
{
return FALSE;
}
else
{
if(LOBYTE(WsaData.wVersion)!=2||HIBYTE(WsaData.wHighVersion)!=2)
{
WSACleanup();
return FALSE;
}
}
return TRUE;
}
//爲NALU_t結構體分配內存空間
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;
}
//釋放
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);
}
}
//這個函數輸入爲一個NAL結構體，主要功能爲得到一個完整的NALU並保存在NALU_t的buf中，
//獲取他的長度，填充F,IDC,TYPE位。
//並且返回兩個開始字符之間間隔的字節數，即包含有前綴的NALU的長度
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;//初始化碼流序列的開始字符爲3個字節
if (3 != fread (Buf, 1, 3, bits))//從碼流中讀3個字節
{
free(Buf);
return 0;
}
info2 = FindStartCode2 (Buf);//判斷是否爲0x000001
if(info2 != 1)
{
//如果不是，再讀一個字節
if(1 != fread(Buf+3, 1, 1, bits))//讀一個字節
{
free(Buf);
return 0;
}
info3 = FindStartCode3 (Buf);//判斷是否爲0x00000001
if (info3 != 1)//如果不是，返回-1
{
free(Buf);
return -1;
}
else
{
//如果是0x00000001,得到開始前綴爲4個字節
pos = 4;
nalu->startcodeprefix_len = 4;
}
}
else
{
//如果是0x000001,得到開始前綴爲3個字節
nalu->startcodeprefix_len = 3;
pos = 3;
}
//查找下一個開始字符的標誌位
StartCodeFound = 0;
info2 = 0;
info3 = 0;
while (!StartCodeFound)
{
if (feof (bits))//判斷是否到了文件尾
{
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);//讀一個字節到BUF中
info3 = FindStartCode3(&Buf[pos-4]);//判斷是否爲0x00000001
if(info3 != 1)
info2 = FindStartCode2(&Buf[pos-3]);//判斷是否爲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))//把文件指針指向前一個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);//拷貝一個完整NALU，不拷貝起始前綴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);//返回兩個開始字符之間間隔的字節數，即包含有前綴的NALU的長度
}
static int FindStartCode2 (unsigned char *Buf)
{
if(Buf[0]!=0 || Buf[1]!=0 || Buf[2] !=1) return 0; //判斷是否爲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;//判斷是否爲0x00000001,如果是返回1
else return 1;
}
int rtpnum = 0;
//輸出NALU長度和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:\\測試數據\\tv480x320.264");
NALU_t *n;
char* nalu_payload;
char sendbuf[1500];
unsigned short seq_num =0;
int bytes=0;
InitWinsock(); //初始化套接字庫
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) ;//申請UDP套接字
n = AllocNALU(8000000);//爲結構體nalu_t及其成員buf分配空間。返回值爲指向nalu_t存儲空間的指針
while(!feof(bits))
{
GetAnnexbNALU(n);//每執行一次，文件的指針指向本次找到的NALU的末尾，下一個位置即爲下個NALU的起始碼0x000001
dump(n);//輸出NALU長度和TYPE
memset(sendbuf,0,1500);//清空sendbuf；此時會將上次的時間戳清空，因此需要ts_current來保存上次的時間戳值
//rtp固定包頭，爲12字節,該句將sendbuf[0]的地址賦給rtp_hdr，以後對rtp_hdr的寫入操作將直接寫入sendbuf。
rtp_hdr =(RTP_FIXED_HEADER*)&sendbuf[0];
//設置RTP HEADER，
rtp_hdr->version = 2; //版本號，此版本固定爲2
rtp_hdr->marker = 0; //標誌位，由具體協議規定其值。
rtp_hdr->payload = H264;//負載類型號，
rtp_hdr->ssrc = htonl(10);//隨機指定爲10，並且在本RTP會話中全局唯一
//當一個NALU小於1400字節的時候，採用一個單RTP包發送
if(n->len<=UDP_MAX_SIZE){
//設置rtp M 位；
rtp_hdr->marker=1;
rtp_hdr->seq_no = htons(seq_num ++); //序列號，每發送一個RTP包增1
//設置NALU HEADER,並將這個HEADER填入sendbuf[12]
nalu_hdr =(NALU_HEADER*)&sendbuf[12]; //將sendbuf[12]的地址賦給nalu_hdr，之後對nalu_hdr的寫入就將寫入sendbuf中；
nalu_hdr->F=n->forbidden_bit;
nalu_hdr->NRI=n->nal_reference_idc>>5;//有效數據在n->nal_reference_idc的第6，7位，需要右移5位才能將其值賦給nalu_hdr->NRI。
nalu_hdr->TYPE=n->nal_unit_type;
nalu_payload=&sendbuf[13];//同理將sendbuf[13]賦給nalu_payload
memcpy(nalu_payload,n->buf+1,n->len-1);//去掉nalu頭的nalu剩餘內容寫入sendbuf[13]開始的字符串。
ts_current=ts_current+timestamp_increse;
rtp_hdr->timestamp=htonl(ts_current);
bytes=n->len + 12 ; //獲得sendbuf的長度,爲nalu的長度（包含NALU頭但除去起始前綴）加上rtp_header的固定長度12字節
send(socket1,sendbuf,bytes,0);//發送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);
//發送第一個的FU，S=1，E=0，R=0
rtp_hdr->seq_no = htons(seq_num ++); //序列號，每發送一個RTP包增1
//設置rtp M 位；
rtp_hdr->marker=0;
//設置FU INDICATOR,並將這個HEADER填入sendbuf[12]
fu_ind =(FU_INDICATOR*)&sendbuf[12]; //將sendbuf[12]的地址賦給fu_ind，之後對fu_ind的寫入就將寫入sendbuf中；
fu_ind->F=n->forbidden_bit;
fu_ind->NRI=n->nal_reference_idc>>5;
fu_ind->TYPE=28;
//設置FU HEADER,並將這個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];//同理將sendbuf[14]賦給nalu_payload
memcpy(nalu_payload,n->buf+1,UDP_MAX_SIZE);//去掉NALU頭
bytes=UDP_MAX_SIZE+14;//獲得sendbuf的長度,爲nalu的長度（除去起始前綴和NALU頭）加上rtp_header，fu_ind，fu_hdr的固定長度14字節
send( socket1, sendbuf, bytes, 0 );//發送RTP包
//發送中間的FU，S=0，E=0，R=0
for(packetIndex=2;packetIndex<packetNum;packetIndex++)
{
rtp_hdr->seq_no = htons(seq_num ++); //序列號，每發送一個RTP包增1
//設置rtp M 位；
rtp_hdr->marker=0;
//設置FU INDICATOR,並將這個HEADER填入sendbuf[12]
fu_ind =(FU_INDICATOR*)&sendbuf[12]; //將sendbuf[12]的地址賦給fu_ind，之後對fu_ind的寫入就將寫入sendbuf中；
fu_ind->F=n->forbidden_bit;
fu_ind->NRI=n->nal_reference_idc>>5;
fu_ind->TYPE=28;
//設置FU HEADER,並將這個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];//同理將sendbuf[14]的地址賦給nalu_payload
memcpy(nalu_payload,n->buf+(packetIndex-1)*UDP_MAX_SIZE+1,UDP_MAX_SIZE);//去掉起始前綴的nalu剩餘內容寫入sendbuf[14]開始的字符串。
bytes=UDP_MAX_SIZE+14;//獲得sendbuf的長度,爲nalu的長度（除去原NALU頭）加上rtp_header，fu_ind，fu_hdr的固定長度14字節
send( socket1, sendbuf, bytes, 0 );//發送rtp包
}
//發送最後一個的FU，S=0，E=1，R=0
rtp_hdr->seq_no = htons(seq_num ++);
//設置rtp M 位；當前傳輸的是最後一個分片時該位置1
rtp_hdr->marker=1;
//設置FU INDICATOR,並將這個HEADER填入sendbuf[12]
fu_ind =(FU_INDICATOR*)&sendbuf[12]; //將sendbuf[12]的地址賦給fu_ind，之後對fu_ind的寫入就將寫入sendbuf中；
fu_ind->F=n->forbidden_bit;
fu_ind->NRI=n->nal_reference_idc>>5;
fu_ind->TYPE=28;
//設置FU HEADER,並將這個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];//同理將sendbuf[14]的地址賦給nalu_payload
memcpy(nalu_payload,n->buf+(packetIndex-1)*UDP_MAX_SIZE+1,lastPackSize-1);//將nalu最後剩餘的-1(去掉了一個字節的NALU頭)字節內容寫入sendbuf[14]開始的字符串。
bytes=lastPackSize-1+14;//獲得sendbuf的長度,爲剩餘nalu的長度l-1加上rtp_header，FU_INDICATOR,FU_HEADER三個包頭共14字節
send( socket1, sendbuf, bytes, 0 );//發送rtp包
}
//Sleep(33);
}
FreeNALU(n);
return 0;
} 將以下文本保存爲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打開該文件，然後運行編譯好的發送程序。
注意頭文件和sdp文件的IP都要與實驗機器的IP吻合。
該代碼在NALDecoder程序基礎上修改了一個內存bug而已。感謝前人的開源。
http://blog.csdn.net/wangjiannuaa/article/details/6694831