// NALDecoder.cpp : Defines the entry point for the console application.
//
#define _CRT_SECURE_NO_WARNINGS
#include
#include
#include
#include
#include
#include "h264.h"
#pragma comment(lib,"ws2_32.lib")
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 bool flag = true;
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
}
//输出NALU长度和TYPE
void dump(NALU_t *n)
{
if (!n)return;
//printf("a new nal:");
printf(" len: %d ", n->len);
printf("nal_unit_type: %x\n", n->nal_unit_type);
}
int main(int argc, char* argv[])
{
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。
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->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(socket1, 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;
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
int t = 0;//用于指示当前发送的是第几个分片RTP包
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(socket1, 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）。
{
//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->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(socket1, sendbuf, bytes, 0);//发送rtp包
t++;
// Sleep(100);
}
else if (t < k && 0 != t)
{
//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(socket1, sendbuf, bytes, 0);//发送rtp包
t++;
}
}
}
}
FreeNALU(n);
return 0;
}
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;
}
#define BOOL bool
#define PACKET_BUFFER_END (unsigned int)0x00000000
#define MAX_RTP_PKT_LENGTH 1400
#define DEST_IP "109.123.104.107"
#define DEST_PORT 1234
#define H264 96
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 */
BOOL InitWinsock();
