//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
}
//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 (sp<ABuffer> nalu)
{
int pos = 0;
int StartCodeFound, rewind;
// unsigned char *Buf;
int info2,info3,startcodeprefix_len,len;
static unsigned char Buf[50000];
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;
startcodeprefix_len = 4;
}
}
else
{
//如果是0x000001,得到开始前缀为3个字节
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
{
//return 0;
len = (pos-1)- startcodeprefix_len;
memcpy (nalu->data(), &Buf[startcodeprefix_len], len);
//free(Buf);
printf("lcy 1991 len %d\n",len);
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
len = (pos+rewind)-startcodeprefix_len;
memcpy (nalu->data(), &Buf[startcodeprefix_len], len);//拷贝一个完整NALU，不拷贝起始前缀0x000001或0x00000001
//free(Buf);
printf("memcpy2\n");
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
}
void CRTPRecv::SendH264Nalu(unsigned char* m_h264Buf,int buflen)
{
//时间戳
//int TimesTampInc=3600;
//Mark标志
//int Mark = 1;
//NAL单元（非发送结构）
NALU_t Nalu;
//待处理的单帧数据指针s
unsigned char *pSendbuf=NULL;
int SendLen=0;
//发送的数据缓冲
char sendbuf[1430];
memset(sendbuf,0,1430);
//上一个startcode位置
int LastStartPos=0;
//本次STARTCODE位置
int StartPos=0;
//前导码为 0x00 00 01 或者 0x00 00 00 01
int DataCount=3;
unsigned char *pData=m_h264Buf;
int res=0;
while (DataCount<buflen)
{
res=FindStartCode3(pData+DataCount-3);
if (res!=true)
{
//未找到前导码
if (DataCount!=buflen-1)
{
DataCount++;
continue;
}
else
{
//最后一段数据
StartPos = buflen;
}
}
else
{
//找到前导码 0x00 00 01
StartPos=DataCount-3;
res=FindStartCode4(pData+DataCount-4);
if(res==true)
{
//找到前导码 0x00 00 00 01
StartPos=DataCount-4;
}
}
//切一个nal进行处理
pSendbuf = pData+LastStartPos;
SendLen = StartPos-LastStartPos;
LastStartPos = StartPos;
DataCount++;
if (SendLen==0)
{
//第一个前导码不用处理
continue;
}
int frontFlag=0;
//去除前导码0x000001 或者0x00000001
if( 0x01 == pSendbuf[2] )
{
pSendbuf = &pSendbuf[3];
SendLen -= 3;
frontFlag=3;
}
else if(0x01==pSendbuf[3])
{
pSendbuf = &pSendbuf[4];
SendLen -= 4;
frontFlag=4;
}
if (SendLen==0)
{
//前导码后没有数据
LOG_WARN("NULL 264 packet");
return;
}
//如果前导码为0x00 00 00 01 表示上一帧已经结束 发送分界nal
/*if (frontFlag==4)
{
m_TimesTampInc=3600;
char buf[6];
memset(buf,0,6);
buf[0]=0x09;
buf[1]=0x30;
SendPacket(buf,6,H264,1,m_TimesTampInc);
m_TimesTampInc=0;
}*/
//解析nal头
NALU_t na;
na.forbidden_bit = pSendbuf[0] & 0x80;
na.nal_reference_idc = (pSendbuf[0] & 0x60)>>5;
na.nal_unit_type = pSendbuf[0] & 0x1f;
int status=0;
//单包
if ( SendLen <= MAX_RTP_PKT_LENGTH )
{
//SetDefaultMark(true);
status = this->SendPacket((void *)pSendbuf,SendLen,H264,1,TIMESTAMP);
}
//分片
else if(SendLen > MAX_RTP_PKT_LENGTH)
{
FU_INDICATOR *pstFuInd;
FU_HEADER *pstFuHdr;
char *pNaluPayLoad;
//解析nal头
Nalu.forbidden_bit = pSendbuf[0] & 0x80;
Nalu.nal_reference_idc = pSendbuf[0] & 0x60;
Nalu.nal_unit_type = pSendbuf[0] & 0x1f;
pSendbuf+=1;
SendLen-=1;
//分片数量
int PackCount=0;
//最后一个分片长度
int RemainLen=0;
PackCount = SendLen / MAX_RTP_PKT_LENGTH;
RemainLen = SendLen % MAX_RTP_PKT_LENGTH;
int PackNumber=0;//用指示当前发送的是第几个分片RTP包
while (PackNumber<=PackCount)
{
pstFuInd = (FU_INDICATOR*)&sendbuf[0];
pstFuInd->F = Nalu.forbidden_bit;
pstFuInd->NRI = Nalu.nal_reference_idc >> 5;
pstFuInd->TYPE = NALU_TYPE_FU_A;
//第一个分片
if (PackNumber==0)
{
pstFuHdr = (FU_HEADER*)&sendbuf[1];
pstFuHdr->E = 0;
pstFuHdr->R = 0;
pstFuHdr->S = 1;
pstFuHdr->TYPE = Nalu.nal_unit_type;
pNaluPayLoad = &sendbuf[2];
memcpy(pNaluPayLoad,pSendbuf+PackNumber*MAX_RTP_PKT_LENGTH,MAX_RTP_PKT_LENGTH);
//SetDefaultMark(false);
status = this->SendPacket((void *)sendbuf,MAX_RTP_PKT_LENGTH+2,H264,0,0);
PackNumber++;
continue;
}
//最后一个分片
else if (((PackNumber==PackCount-1)&&RemainLen==0)||((PackNumber==PackCount)&&(RemainLen!=0)))
{
pstFuHdr = (FU_HEADER*)&sendbuf[1];
pstFuHdr->E = 1;
pstFuHdr->R = 0;
pstFuHdr->S = 0;
pstFuHdr->TYPE = Nalu.nal_unit_type;
pNaluPayLoad = &sendbuf[2];
//SetDefaultMark(true);
if (RemainLen==0)
{
memcpy(pNaluPayLoad,pSendbuf+PackNumber*MAX_RTP_PKT_LENGTH,MAX_RTP_PKT_LENGTH);
status = this->SendPacket((void *)sendbuf,MAX_RTP_PKT_LENGTH+2,H264,1,0);
}
else
{
memcpy(pNaluPayLoad,pSendbuf+PackNumber*MAX_RTP_PKT_LENGTH,RemainLen);
status = this->SendPacket((void *)sendbuf,RemainLen+2,H264,1,TIMESTAMP);
}
break;
}
//中间分片
else
{
pstFuHdr = (FU_HEADER*)&sendbuf[1];
pstFuHdr->E = 0;
pstFuHdr->R = 0;
pstFuHdr->S = 0;
pstFuHdr->TYPE = Nalu.nal_unit_type;
pNaluPayLoad = &sendbuf[2];
memcpy(pNaluPayLoad,pSendbuf+PackNumber*MAX_RTP_PKT_LENGTH,MAX_RTP_PKT_LENGTH);
//SetDefaultMark(false);
status = this->SendPacket((void *)sendbuf,MAX_RTP_PKT_LENGTH+2,H264,0,0);
PackNumber++;
continue;
}
}
}
}
