RTP打包发送H.264——纯代码，直接上

http://blog.csdn.net/bytxl/article/details/50463925

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
");
        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
");

    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->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。

http://blog.csdn.net/wangjiannuaa/article/details/6694831