最近考慮使用RTP替換原有的高清視頻傳輸協(xié)議,遂上網(wǎng)查找有關H264視頻RTP打包、解包的文檔和代碼。功夫不負有心人,找到不少有價值的文檔和代碼。參考這些資料,寫了H264 RTP打包類、解包類,實現(xiàn)了單個NAL單元包和FU_A分片單元包。對于丟包處理,采用簡單的策略:丟棄隨后的所有數(shù)據(jù)包,直到收到關鍵幀。測試效果還不錯,代碼貼上來,若能為同道中人借鑒一二,足矣。兩個類的使用說明如下(省略了錯誤處理過程):
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
// ...
}
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
// ...
}
-
-
-
- class CH264_RTP_PACK
- {
- #define RTP_VERSION 2
-
- typedef struct NAL_msg_s
- {
- bool eoFrame ;
- unsigned char type;
- unsigned char *start;
- unsigned char *end;
- unsigned long size ;
- } NAL_MSG_t;
-
- typedef struct
- {
-
- unsigned short cc:4;
- unsigned short x:1;
- unsigned short p:1;
- unsigned short v:2;
- unsigned short pt:7;
- unsigned short m:1;
-
- unsigned short seq;
- unsigned long ts;
- unsigned long ssrc;
- } rtp_hdr_t;
-
- typedef struct tagRTP_INFO
- {
- NAL_MSG_t nal;
- rtp_hdr_t rtp_hdr;
- int hdr_len;
-
- unsigned char *pRTP;
- unsigned char *start;
- unsigned char *end;
-
- unsigned int s_bit;
- unsigned int e_bit;
- bool FU_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)
- {
- }
-
-
-
-
- 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 ;
-
- 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 ;
- }
- 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 ;
- }
-
-
- 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;
- }
-
- int bytesLeft = m_RTP_Info.nal.end - m_RTP_Info.start ;
- int maxSize = m_MAXRTPPACKSIZE - 12 ;
- if ( m_RTP_Info.FU_flag )
- maxSize -= 2 ;
-
- if ( bytesLeft > maxSize )
- {
- 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 )
- {
- 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 ;
- 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 ;
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
- if ( m_RTP_Info.FU_flag )
- {
-
- cp[12] = ( m_RTP_Info.nal.type & 0xe0 ) | 28 ;
-
- cp[13] = ( m_RTP_Info.s_bit << 7 ) | ( m_RTP_Info.e_bit << 6 ) | ( m_RTP_Info.nal.type & 0x1f ) ;
-
- 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] ;
-
- *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_UNPACK
- {
-
- #define RTP_VERSION 2
- #define BUF_SIZE (1024 * 500)
-
- typedef struct
- {
-
- unsigned short cc:4;
- unsigned short x:1;
- unsigned short p:1;
- unsigned short v:2;
- unsigned short pt:7;
- unsigned short m:1;
-
- unsigned short seq;
- unsigned long ts;
- unsigned long ssrc;
- } 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 ;
- }
-
-
-
- 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 ;
-
-
- if ( m_RTP_Header.v != RTP_VERSION )
- {
- return NULL ;
- }
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
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-
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-
-
-
-
-
-
-
-
-
- if ( m_RTP_Header.pt != m_H264PAYLOADTYPE )
- {
- return NULL ;
- }
-
- int PayloadType = pPayload[0] & 0x1f ;
- int NALType = PayloadType ;
- if ( NALType == 28 )
- {
- 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 )
- {
- m_bSPSFound = true ;
- }
-
- if ( !m_bSPSFound )
- {
- return NULL ;
- }
-
- if ( NALType == 0x07 || NALType == 0x08 )
- {
- 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 )
- {
- 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 )
- {
- m_wSeq = m_RTP_Header.seq ;
- m_bPrevFrameEnd = false ;
- return NULL ;
- }
- }
- }
-
-
-
-
- if ( m_RTP_Header.seq != (WORD)( m_wSeq + 1 ) )
- {
- m_wSeq = m_RTP_Header.seq ;
- SetLostPacket () ;
- return NULL ;
- }
- else
- {
-
-
- m_wSeq = m_RTP_Header.seq ;
- m_bAssemblingFrame = true ;
-
- if ( PayloadType != 28 )
- {
- *((DWORD*)(m_pStart)) = 0x01000000 ;
- m_pStart += 4 ;
- m_dwSize += 4 ;
- }
- else
- {
- if ( pPayload[1] & 0x80 )
- {
- *((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
- {
- SetLostPacket () ;
- return NULL ;
- }
-
- if ( m_RTP_Header.m )
- {
- *outSize = m_dwSize ;
-
- m_pStart = m_pBuf ;
- m_dwSize = 0 ;
-
- if ( NALType == 0x05 )
- {
- 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 ;
- };
-
-
-