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RTP封包拆包

RTP封包拆包
RTP封包拆包

////////////////////////////////////////////////////////////////// ////////////////////////

// class CH264_RTP_PACK start

class CH264_RTP_PACK

{

#define RTP_VERSION 2

typedef struct NAL_msg_s

{

bool eoFrame ;

unsigned char type; // NAL type

unsigned char *start; // pointer to first location in the send buffer

unsigned char *end; // pointer to last location in send buffer unsigned long size ;

} NAL_MSG_t;

typedef struct

{

//LITTLE_ENDIAN

unsigned short cc:4; /* CSRC count */

unsigned short x:1; /* header extension flag */

unsigned short p:1; /* padding flag */

unsigned short v:2; /* packet type */

unsigned short pt:7; /* payload type */

unsigned short m:1; /* marker bit */

unsigned short seq; /* sequence number */

unsigned long ts; /* timestamp */

unsigned long ssrc; /* synchronization source */ } rtp_hdr_t;

typedef struct tagRTP_INFO

{

NAL_MSG_t nal; // NAL information

rtp_hdr_t rtp_hdr; // RTP header is assembled here

int hdr_len; // length of RTP header

unsigned char *pRTP; // pointer to where RTP packet has beem assembled

unsigned char *start; // pointer to start of payload

unsigned char *end; // pointer to end of payload

unsigned int s_bit; // bit in the FU header

unsigned int e_bit; // bit in the FU header

bool FU_flag; // fragmented NAL Unit flag

} RTP_INFO;

public:

CH264_RTP_PACK(unsigned long H264SSRC, unsigned char H264PAYLOADTYPE=96, unsigned short MAXRTPPACKSIZE=1472 ) {

m_MAXRTPPACKSIZE = MAXRTPPACKSIZE ;

if ( m_MAXRTPPACKSIZE > 10000 )

{

m_MAXRTPPACKSIZE = 10000 ;

}

if ( m_MAXRTPPACKSIZE < 50 )

{

m_MAXRTPPACKSIZE = 50 ;

}

memset ( &m_RTP_Info, 0, sizeof(m_RTP_Info) ) ;

m_RTP_Info.rtp_hdr.pt = H264PAYLOADTYPE ;

m_RTP_Info.rtp_hdr.ssrc = H264SSRC ;

m_RTP_Info.rtp_hdr.v = RTP_VERSION ;

m_RTP_Info.rtp_hdr.seq = 0 ;

}

~CH264_RTP_PACK(void)

{

}

//′?è?Setμ?êy?Y±?D?ê?ò???íê??μ?NAL,?eê????a0x00000001?£

//?eê??????°?áéù?¤á?10??×??ú£?ò?±ü?a?ú′?COPY2ù×÷?£

//′ò°üíê3éoó£??-?o3????úμ?êy?Y±????μ?£

bool Set ( unsigned char *NAL_Buf, unsigned long NAL_Size, unsigned long Time_Stamp, bool End_Of_Frame )

{

unsigned long startcode = StartCode(NAL_Buf) ;

if ( startcode != 0x01000000 )

{

return false ;

}

int type = NAL_Buf[4] & 0x1f ;

if ( type < 1 || type > 12 )

{

return false ;

}

m_RTP_Info.nal.start = NAL_Buf ;

m_RTP_Info.nal.size = NAL_Size ;

m_RTP_Info.nal.eoFrame = End_Of_Frame ;

m_RTP_Info.nal.type = m_RTP_Info.nal.start[4] ;

m_RTP_Info.nal.end = m_RTP_Info.nal.start + m_RTP_Info.nal.size ;

m_RTP_Info.rtp_hdr.ts = Time_Stamp ;

m_RTP_Info.nal.start += 4 ; // skip the syncword

if ( (m_RTP_Info.nal.size + 7) > m_MAXRTPPACKSIZE )

{

m_RTP_Info.FU_flag = true ;

m_RTP_Info.s_bit = 1 ;

m_RTP_Info.e_bit = 0 ;

m_RTP_Info.nal.start += 1 ; // skip NAL header }

else

{

m_RTP_Info.FU_flag = false ;

m_RTP_Info.s_bit = m_RTP_Info.e_bit = 0 ;

}

m_RTP_Info.start = m_RTP_Info.end = m_RTP_Info.nal.start ;

m_bBeginNAL = true ;

return true ;

}

//?-?·μ÷ó?Get??è?RTP°ü£??±μ?·μ???μ?aNULL

unsigned char* Get ( unsigned short *pPacketSize )

{

if ( m_RTP_Info.end == m_RTP_Info.nal.end )

{

*pPacketSize = 0 ;

return NULL ;

}

if ( m_bBeginNAL )

{

m_bBeginNAL = false ;

}

else

{

m_RTP_Info.start = m_RTP_Info.end; // continue with the next RTP-FU packet

}

int bytesLeft = m_RTP_Info.nal.end - m_RTP_Info.start ;

int maxSize = m_MAXRTPPACKSIZE - 12 ; // sizeof(basic rtp header) == 12 bytes

if ( m_RTP_Info.FU_flag )

maxSize -= 2 ;

if ( bytesLeft > maxSize )

{

m_RTP_Info.end = m_RTP_Info.start + maxSize ; // limit RTP packetsize to 1472 bytes

}

else

{

m_RTP_Info.end = m_RTP_Info.start + bytesLeft ;

}

if ( m_RTP_Info.FU_flag )

{ // multiple packet NAL slice

if ( m_RTP_Info.end == m_RTP_Info.nal.end )

{

m_RTP_Info.e_bit = 1 ;

}

}

m_RTP_Info.rtp_hdr.m = m_RTP_Info.nal.eoFrame ? 1 : 0 ; // should be set at EofFrame

if ( m_RTP_Info.FU_flag && !m_RTP_Info.e_bit )

{

m_RTP_Info.rtp_hdr.m = 0 ;

}

m_RTP_Info.rtp_hdr.seq++ ;

unsigned char *cp = m_RTP_Info.start ;

cp -= ( m_RTP_Info.FU_flag ? 14 : 12 ) ;

m_RTP_Info.pRTP = cp ;

unsigned char *cp2 = (unsigned char *)&m_RTP_Info.rtp_hdr ; cp[0] = cp2[0] ;

cp[1] = cp2[1] ;

cp[2] = ( m_RTP_Info.rtp_hdr.seq >> 8 ) & 0xff ;

cp[3] = m_RTP_Info.rtp_hdr.seq & 0xff ;

cp[4] = ( m_RTP_Info.rtp_hdr.ts >> 24 ) & 0xff ;

cp[5] = ( m_RTP_Info.rtp_hdr.ts >> 16 ) & 0xff ;

cp[6] = ( m_RTP_Info.rtp_hdr.ts >> 8 ) & 0xff ;

cp[7] = m_RTP_Info.rtp_hdr.ts & 0xff ;

cp[8] = ( m_RTP_Info.rtp_hdr.ssrc >> 24 ) & 0xff ;

cp[9] = ( m_RTP_Info.rtp_hdr.ssrc >> 16 ) & 0xff ;

cp[10] = ( m_RTP_Info.rtp_hdr.ssrc >> 8 ) & 0xff ;

cp[11] = m_RTP_Info.rtp_hdr.ssrc & 0xff ;

m_RTP_Info.hdr_len = 12 ;

/*!

* /n The FU indicator octet has the following format:

* /n

* /n +---------------+

* /n MSB |0|1|2|3|4|5|6|7| LSB

* /n +-+-+-+-+-+-+-+-+

* /n |F|NRI| Type |

* /n +---------------+

* /n

* /n The FU header has the following format:

* /n

* /n +---------------+

* /n |0|1|2|3|4|5|6|7|

* /n +-+-+-+-+-+-+-+-+

* /n |S|E|R| Type |

* /n +---------------+

*/

if ( m_RTP_Info.FU_flag )

{

// FU indicator F|NRI|Type

cp[12] = ( m_RTP_Info.nal.type & 0xe0 ) | 28 ; //Type is

28 for FU_A

//FU header S|E|R|Type

cp[13] = ( m_RTP_Info.s_bit << 7 ) | ( m_RTP_Info.e_bit << 6 ) | ( m_RTP_Info.nal.type & 0x1f ) ; //R = 0, must be ignored by receiver

m_RTP_Info.s_bit = m_RTP_Info.e_bit= 0 ;

m_RTP_Info.hdr_len = 14 ;

}

m_RTP_Info.start = &cp[m_RTP_Info.hdr_len] ; // new start of payload

*pPacketSize = m_RTP_Info.hdr_len + ( m_RTP_Info.end - m_RTP_Info.start ) ;

return m_RTP_Info.pRTP ;

}

private:

unsigned int StartCode( unsigned char *cp )

{

unsigned int d32 ;

d32 = cp[3] ;

d32 <<= 8 ;

d32 |= cp[2] ;

d32 <<= 8 ;

d32 |= cp[1] ;

d32 <<= 8 ;

d32 |= cp[0] ;

return d32 ;

}

private:

RTP_INFO m_RTP_Info ;

bool m_bBeginNAL ;

unsigned short m_MAXRTPPACKSIZE ;

};

// class CH264_RTP_PACK end

////////////////////////////////////////////////////////////////// ////////////////////////

////////////////////////////////////////////////////////////////// ////////////////////////

// class CH264_RTP_UNPACK start

class CH264_RTP_UNPACK

{

#define RTP_VERSION 2

#define BUF_SIZE (1024 * 500)

typedef struct

{

//LITTLE_ENDIAN

unsigned short cc:4; /* CSRC count */

unsigned short x:1; /* header extension flag */

unsigned short p:1; /* padding flag */

unsigned short v:2; /* packet type */

unsigned short pt:7; /* payload type */

unsigned short m:1; /* marker bit */

unsigned short seq; /* sequence number */

unsigned long ts; /* timestamp */

unsigned long ssrc; /* synchronization source */ } rtp_hdr_t;

public:

CH264_RTP_UNPACK ( HRESULT &hr, unsigned char H264PAYLOADTYPE = 96 ) : m_bSPSFound(false)

, m_bWaitKeyFrame(true)

, m_bPrevFrameEnd(false)

, m_bAssemblingFrame(false)

, m_wSeq(1234)

, m_ssrc(0)

{

m_pBuf = new BYTE[BUF_SIZE] ;

if ( m_pBuf == NULL )

{

hr = E_OUTOFMEMORY ;

return ;

}

m_H264PAYLOADTYPE = H264PAYLOADTYPE ;

m_pEnd = m_pBuf + BUF_SIZE ;

m_pStart = m_pBuf ;

m_dwSize = 0 ;

hr = S_OK ;

}

~CH264_RTP_UNPACK(void)

{

delete [] m_pBuf ;

}

//pBuf?aH264

RTPêó?μêy?Y°ü£?nSize?aRTPêó?μêy?Y°ü×??ú3¤?è£?outSize?aê?3?êó?μêy?Y??×??ú3¤?è?£

//·μ???μ?a???òêó?μêy?Y??μ??????£ê?è?êy?Y?é?ü±????μ?£

BYTE* Parse_RTP_Packet ( BYTE *pBuf, unsigned short nSize, int *outSize )

{

if ( nSize <= 12 )

{

return NULL ;

}

BYTE *cp = (BYTE*)&m_RTP_Header ;

cp[0] = pBuf[0] ;

cp[1] = pBuf[1] ;

m_RTP_Header.seq = pBuf[2] ;

m_RTP_Header.seq <<= 8 ;

m_RTP_Header.seq |= pBuf[3] ;

m_RTP_Header.ts = pBuf[4] ;

m_RTP_Header.ts <<= 8 ;

m_RTP_Header.ts |= pBuf[5] ;

m_RTP_Header.ts <<= 8 ;

m_RTP_Header.ts |= pBuf[6] ;

m_RTP_Header.ts <<= 8 ;

m_RTP_Header.ts |= pBuf[7] ;

m_RTP_Header.ssrc = pBuf[8] ;

m_RTP_Header.ssrc <<= 8 ;

m_RTP_Header.ssrc |= pBuf[9] ;

m_RTP_Header.ssrc <<= 8 ;

m_RTP_Header.ssrc |= pBuf[10] ;

m_RTP_Header.ssrc <<= 8 ;

m_RTP_Header.ssrc |= pBuf[11] ;

BYTE *pPayload = pBuf + 12 ;

DWORD PayloadSize = nSize - 12 ;

// Check the RTP version number (it should be 2): if ( m_RTP_Header.v != RTP_VERSION )

{

return NULL ;

}

/*

// Skip over any CSRC identifiers in the header: if ( m_RTP_https://www.doczj.com/doc/0415242176.html, )

{

long cc = m_RTP_https://www.doczj.com/doc/0415242176.html, * 4 ;

if ( Size < cc )

{

return NULL ;

}

Size -= cc ;

p += cc ;

}

// Check for (& ignore) any RTP header extension if ( m_RTP_Header.x )

{

if ( Size < 4 )

{

return NULL ;

}

Size -= 4 ;

p += 2 ;

long l = p[0] ;

l <<= 8 ;

l |= p[1] ;

p += 2 ;

l *= 4 ;

if ( Size < l ) ;

{

return NULL ;

}

Size -= l ;

p += l ;

}

// Discard any padding bytes:

if ( m_RTP_Header.p )

{

if ( Size == 0 )

{

return NULL ;

}

long Padding = p[Size-1] ;

if ( Size < Padding )

{

return NULL ;

}

Size -= Padding ;

}*/

// Check the Payload Type.

if ( m_RTP_Header.pt != m_H264PAYLOADTYPE ) {

return NULL ;

}

int PayloadType = pPayload[0] & 0x1f ;

int NALType = PayloadType ;

if ( NALType == 28 ) // FU_A

{

if ( PayloadSize < 2 )

{

return NULL ;

}

NALType = pPayload[1] & 0x1f ;

}

if ( m_ssrc != m_RTP_Header.ssrc )

{

m_ssrc = m_RTP_Header.ssrc ;

SetLostPacket () ;

}

if ( NALType == 0x07 ) // SPS

{

m_bSPSFound = true ;

}

if ( !m_bSPSFound )

{

return NULL ;

}

if ( NALType == 0x07 || NALType == 0x08 ) // SPS PPS {

m_wSeq = m_RTP_Header.seq ;

m_bPrevFrameEnd = true ;

pPayload -= 4 ;

*((DWORD*)(pPayload)) = 0x01000000 ;

*outSize = PayloadSize + 4 ;

return pPayload ;

}

if ( m_bWaitKeyFrame )

{

if ( m_RTP_Header.m ) // frame end

{

m_bPrevFrameEnd = true ;

if ( !m_bAssemblingFrame )

{

m_wSeq = m_RTP_Header.seq ;

return NULL ;

}

}

if ( !m_bPrevFrameEnd )

{

m_wSeq = m_RTP_Header.seq ;

return NULL ;

}

else

{

if ( NALType != 0x05 ) // KEY FRAME

{

m_wSeq = m_RTP_Header.seq ;

m_bPrevFrameEnd = false ;

return NULL ;

}

}

}

///////////////////////////////////////////////////////////////

if ( m_RTP_Header.seq != (WORD)( m_wSeq + 1 ) ) // lost packet {

m_wSeq = m_RTP_Header.seq ;

SetLostPacket () ;

return NULL ;

}

else

{

// ??á÷?y3£

m_wSeq = m_RTP_Header.seq ;

m_bAssemblingFrame = true ;

if ( PayloadType != 28 ) // whole NAL

{

*((DWORD*)(m_pStart)) = 0x01000000 ;

m_pStart += 4 ;

m_dwSize += 4 ;

}

else // FU_A

{

if ( pPayload[1] & 0x80 ) // FU_A start

{

*((DWORD*)(m_pStart)) = 0x01000000 ;

m_pStart += 4 ;

m_dwSize += 4 ;

pPayload[1] = ( pPayload[0] & 0xE0 ) | NALType ;

pPayload += 1 ;

PayloadSize -= 1 ;

}

else

{

pPayload += 2 ;

PayloadSize -= 2 ;

}

}

if ( m_pStart + PayloadSize < m_pEnd )

{

CopyMemory ( m_pStart, pPayload, PayloadSize ) ;

m_dwSize += PayloadSize ;

m_pStart += PayloadSize ;

}

else // memory overflow

{

SetLostPacket () ;

return NULL ;

}

if ( m_RTP_Header.m ) // frame end

{

*outSize = m_dwSize ;

m_pStart = m_pBuf ;

m_dwSize = 0 ;

if ( NALType == 0x05 ) // KEY FRAME

{

m_bWaitKeyFrame = false ;

}

return m_pBuf ;

}

else

{

return NULL ;

}

}

}

void SetLostPacket()

{

m_bSPSFound = false ;

m_bWaitKeyFrame = true ;

m_bPrevFrameEnd = false ;

m_bAssemblingFrame = false ;

m_pStart = m_pBuf ;

m_dwSize = 0 ;

}

private:

rtp_hdr_t m_RTP_Header ;

BYTE *m_pBuf ;

bool m_bSPSFound ;

bool m_bWaitKeyFrame ;

bool m_bAssemblingFrame ;

bool m_bPrevFrameEnd ;

BYTE *m_pStart ;

BYTE *m_pEnd ;

DWORD m_dwSize ;

WORD m_wSeq ;

BYTE m_H264PAYLOADTYPE ;

DWORD m_ssrc ;

};

// class CH264_RTP_UNPACK end

////////////////////////////////////////////////////////////////// ////////////////////////

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