H264相关代码

H.264格式的视频打包成RTP后进行发送，编译环境为VC6++

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <memory.h>

#include <winsock2.h>
#pragma comment(lib,"ws2_32.lib")
#include <Windows.h>

#define PACKET_BUFFER_END       (unsigned int)0x00000000
#define MAX_RTP_PKT_LENGTH         1400
#define DEST_IP                    "127.0.0.1"
#define DEST_PORT                1234
#define H264                    96

FILE *bits = NULL;                //!< the bit stream file



typedef struct 

{
    
    /**//* byte 0 */
    unsigned char csrc_len:4;        /**//* expect 0 */
    unsigned char extension:1;        /**//* expect 1, see RTP_OP below */
    unsigned char padding:1;        /**//* expect 0 */
    unsigned char version:2;        /**//* expect 2 */
    
    /**//* byte 1 */
    unsigned char payload:7;        /**//* RTP_PAYLOAD_RTSP */
    unsigned char marker:1;        /**//* expect 1 */
    
    /**//* bytes 2, 3 */
    unsigned short seq_no;            
    
    /**//* bytes 4-7 */
    unsigned  long timestamp;        
    
    /**//* bytes 8-11 */
    unsigned long ssrc;            /**//* stream number is used here. */
    
} RTP_FIXED_HEADER;

typedef struct {
    
    //byte 0
    unsigned char TYPE:5;
    unsigned char NRI:2;
    unsigned char F:1;            
    
} NALU_HEADER; /**//* 1 BYTES */

typedef struct {
    //byte 0
    unsigned char TYPE:5;
    unsigned char NRI:2; 
    unsigned char F:1;    
    
} FU_INDICATOR; /**//* 1 BYTES */


typedef struct {
    
    //byte 0
    unsigned char TYPE:5;
    unsigned char R:1;
    unsigned char E:1;
    unsigned char S:1;    
    
} FU_HEADER; /**//* 1 BYTES */


typedef struct
{
    
    int startcodeprefix_len;      //! 4 for parameter sets and first slice in picture, 3 for everything else (suggested)
    unsigned int len;             //! Length of the NAL unit (Excluding the start code, which does not belong to the NALU)
    unsigned int 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;



//查找开始字符0x000001
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;
    
}

//查找开始字符0x00000001
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;
}


//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);
    }
}

//打开二进制文件串流
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;
    int info2=0, info3=0;
    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;    //得到一个NAL单元长度
    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
    
}

//输出NALU长度和TYPE
void dump(NALU_t *n)
{
    
    if (!n)
        return;
    
    printf(" len: %d  ", n->len);
    printf("nal_unit_type: %x\n", n->nal_unit_type);
    
}



RTP_FIXED_HEADER        *rtp_hdr;
NALU_HEADER        *nalu_hdr;
FU_INDICATOR    *fu_ind;
FU_HEADER        *fu_hdr;

int main(int argc, char* argv[])
{
    WSADATA  Ws;
    NALU_t *n;
    char* nalu_payload;  
    char sendbuf[1500];
    unsigned short seq_num =0;
    int    bytes=0;
    int sockfd;
    struct sockaddr_in serv_addr;


    //int len =sizeof(serv_addr);

    float framerate=15;
    unsigned int timestamp_increse=0,ts_current=0;
    timestamp_increse=(unsigned int)(90000.0 / framerate); //+0.5);
    
    
    OpenBitstreamFile("./test.264");//打开264文件，并将文件指针赋给bits,在此修改文件名实现打开别的264文件。
    
    //Init Windows Socket
    if ( WSAStartup(MAKEWORD(2,2), &Ws) != 0 )
    {
        printf("Init Windows Socket Failed::%d\n",GetLastError());
        return -1;
    }
    
    if ((sockfd = socket(AF_INET,SOCK_DGRAM,0)) == -1)
    {
        perror("socket");
        exit(1);
    }

    /*设置socketaddr_in结构体中相关参数*/
    serv_addr.sin_family=AF_INET;
    serv_addr.sin_port=htons(DEST_PORT);          
    serv_addr.sin_addr.s_addr=inet_addr(DEST_IP); 

    /*调用connect函数主动发起对服务器端的连接*/
    if(connect(sockfd,(struct sockaddr *)&serv_addr, sizeof(struct sockaddr))== -1)
    {
        perror("connect");
        exit(1);
    }

    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->payload     = H264;                   //负载类型号
        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->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<=1400)
        {    
            //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( sockfd, sendbuf, bytes, 0 );         //发送rtp包
            //    Sleep(100);

        }

        else if(n->len>1400)
        {
            //得到该nalu需要用多少长度为1400字节的RTP包来发送
            int k=0,l=0;
            int t=0;                                    //用于指示当前发送的是第几个分片RTP包
            k=n->len/1400;                              //需要k个1400字节的RTP包
            l=n->len%1400;                              //最后一个RTP包的需要装载的字节数
            ts_current=ts_current+timestamp_increse;
            rtp_hdr->timestamp=htonl(ts_current);
            while(t<=k)
            {
                rtp_hdr->seq_no = htons(seq_num ++); //序列号，每发送一个RTP包增1
                if(!t)//发送一个需要分片的NALU的第一个分片，置FU HEADER的S位
                {
                    //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->E=0;
                    fu_hdr->R=0;
                    fu_hdr->S=1;
                    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+1,1400);    //去掉NALU头
                
                    bytes=1400+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( sockfd, sendbuf, bytes, 0 );    //发送rtp包
                    t++;
                }
                //发送一个需要分片的NALU的非第一个分片，清零FU HEADER的S位，如果该分片是该NALU的最后一个分片，置FU HEADER的E位
                else if(k==t)//发送的是最后一个分片，注意最后一个分片的长度可能超过1400字节（当l>1386时）。
                {

                    
                    rtp_hdr->marker=1;                     //设置rtp M 位；当前传输的是最后一个分片时该位置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->R=0;
                    fu_hdr->S=0;
                    fu_hdr->TYPE=n->nal_unit_type;
                    fu_hdr->E=1;

                    nalu_payload=&sendbuf[14];               //同理将sendbuf[14]的地址赋给nalu_payload
                    memcpy(nalu_payload,n->buf+t*1400+1,l-1);//将nalu最后剩余的l-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=l-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( sockfd, sendbuf, bytes, 0 );       //发送rtp包
                    t++;
                //    Sleep(100);
                }

                else if(t<k&&0!=t)
                {

                    //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->E=0;
                    fu_hdr->R=0;
                    fu_hdr->S=0;
                    fu_hdr->E=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+t*1400+1,1400); //去掉起始前缀的nalu剩余内容写入sendbuf[14]开始的字符串。
                    bytes=1400+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( sockfd, sendbuf, bytes, 0 );         //发送rtp包
                    t++;
                }

            }

        }

    }

    send( sockfd, "over",4, 0 );//发送结束标志
    FreeNALU(n);

    closesocket(sockfd);
    WSACleanup();
    return 0;

}

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