基于RTP的H264视频数据打包解包类

RTP打包H264 NALU类使用范例代码：

DWORD H264SSRC ;

CH264_RTP_PACK pack ( H264SSRC ) ;

BYTE *pVideoData ;

DWORD Size, ts ;

bool IsEndOfFrame ;

WORD wLen ;

pack.Set ( pVideoData, Size, ts, IsEndOfFrame ) ;

BYTE *pPacket ;

while ( pPacket = pack.Get ( &wLen ) )

{

// rtp packet process

// ...

}

RTP 承载H.264 Payload NALU 的打包类源码

// 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)

{

}

//传入Set的数据必须是一个完整的NAL,起始码为0x00000001。

//起始码之前至少预留10个字节，以避免内存COPY操作。

//打包完成后，原缓冲区内的数据被破坏。

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 ;

}

//循环调用Get获取RTP包，直到返回值为NULL

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 )

{

// limit RTP packetsize to 1472 bytes

m_RTP_Info.end = m_RTP_Info.start + maxSize ;

}

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 ;

}

}

// should be set at EofFrame

m_RTP_Info.rtp_hdr.m = m_RTP_Info.nal.eoFrame ? 1 : 0 ;

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

RTP 承载H.264 Payload的解包类源码 // 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为H264 RTP视频数据包，nSize为RTP视频数据包字节长度，outSize为输出视频数据帧字节长度。 //返回值为指向视频数据帧的指针。输入数据可能被破坏。 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_Header.cc ) { long cc = m_RTP_Header.cc * 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 { // 码流正常 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 使用范例： HRESULT hr ; CH264_RTP_UNPACK unpack ( hr ) ; BYTE *pRtpData ; WORD inSize; int outSize ; BYTE *pFrame = unpack.Parse_RTP_Packet ( pRtpData, inSize, &outSize ) ; if ( pFrame != NULL ) { // frame process // ... }

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