H.264的RTP封包和解包

H264RTP封包方法

(2010-02-20 10:08:08)转载

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杂谈

分类：多媒体可以通过生成SDP文件给播放器在指定端口接收数据播放,如果你不用动态调整编码器什么的就不用考虑另外发送RTCP. 而且RTCP必须自己实现RTSP服务结合起来用,没有实现RTSP服务,就谈不上实现RTCP. 具体H264字节流拆包和RTP封包方法如下
UINT MediaStreamH264::TransportData(PBYTE pData, UINT dataSize, int pts)
{ PBYTE p_buffer = pData;
inti_buffer = dataSize;
UINT writeSize = 0;
while( i_buffer > 4 && ( p_buffer[0] != 0 || p_buffer[1] != 0 || p_buffer[2] != 1 ) )
{ i_buffer--; p_buffer++; }

while( i_buffer > 4 )
{ int i_offset; int i_size = i_buffer;
int i_skip = i_buffer; /
* search nal end */
for( i_offset = 4; i_offset+2 < i_buffer ; i_offset++)
{ if( p_buffer[i_offset] == 0 && p_buffer[i_offset+1] == 0 && p_buffer[i_offset+2] == 1 )
{

i_size = i_offset - ( p_buffer[i_offset-1] == 0 ? 1 : 0);
i_skip = i_offset; break; }
}

UINT iWrite = TransportH264Nal(p_buffer, i_size, pts, (i_size >= i_buffer) );
if (iWrite > 0 ) writeSize += iWrite;
i_buffer -= i_skip;
p_buffer += i_skip;
}
return writeSize; }
UINT MediaStreamH264::TransportH264Nal(const PBYTE pNal, UINT nalSize, INT32 pts, BOOL isLast)
{ ATLock atlock(&m_tlockRun);
if (m_bRun == FALSE)
return 0;
if( nalSize < 5 )
return 0;
UINTmtu = m_nMTU;
const int i_max = mtu - RTP_HEADER_SIZE;

int i_nal_hdr;
int i_nal_type;
i_nal_hdr = pNal[3];
i_nal_type = i_nal_hdr&0x1f;
string sps;
string pps;
if( i_nal_type == 7 || i_nal_type == 8 )
{
return 0;
}

PBYTE p_data = pNal;
inti_data = nalSize;
p_data += 3;
i_data -= 3;
int writeSize = 0;
if( i_data <= i_max )
{

writeSize = m_pRtpTransport->SetRtpData(p_data, i_data, pts, isLast); writeSize = m_pRtpTransport->Write(p_data, i_data, m_nRtpPayloadType, pts, 0, isLast);
if (writeSize <= 0)
return 0;
return writeSize;
}
else
{

const int i_count = ( i_data-1 + i_max-2 - 1 ) / (i_max-2);
int i;
p_data++;
i_data--;
for( i = 0; i < i_count; i++ )
{ const int i_payload = (i_data < (i_max-2)) ? i_data : (i_max-2);
const int nalSize = 2 + i_payload;
m_Packet.ExtendBuffer(nalSize);

m_Packet.m_pData[0] = 0x00 | (i_nal_hdr & 0x60) | 28;

m_Packet.m_pData[1] = ( i == 0 ? 0x80 : 0x00 ) | ( (i == i_count-1) ? 0x40 : 0x00 ) | i_nal_type;

memcpy( &m_Packet.m_pData[2], p_data, i_payload );
m_Packet.m_DataSize = nalSize;
//int iWrite = m_pRtpTransport->SetRtpData(m_Packet.m_pData,m_Packet.m_DataSize, pts, isLast && (i == i_count-1));
int iWrite = m_pRtpTransport->Write(m_Packet.m_pData,m_Packet.m_DataSize, m_nRtpPayloadType, pts, 0,isLast && (i == i_count-1));
if (iWrite > 0)
writeSize += iWrite;
i_data -= i_payload;
p_data += i_payload; }
}
return writeSize; }

RTP拆包如下：

UINT MediaStreamH264::TransportH264Nal(const PBYTE pNal, UINT nalSize, INT32 pts, BOOL isLast)
{
ATLock atlock(&m_tlockRun);
if (m_bRun == FALSE)
return 0;
if( nalSize < 5 )
return 0;
UINT mtu = m_nMTU;
const int i_max = mtu - RTP_HEADER_SIZE;
int i_nal_hdr;
int i_nal_type;
i_nal_hdr = pNal[3];
i_nal_type = i_nal_hdr&0x1f;

string sps;
string pps;
if( i_nal_type == 7 || i_nal_type == 8 )
{

return 0;
}

PBYTE p_data = pNal;
int i_data = nalSize;
p_data += 3;
i_data -= 3;
int writeSize = 0;
if( i_data <= i_max )
{

//writeSize = m_pRtpTransport->SetRtpData(p_data, i_data, pts, isLast);
writeSize = m_pRtpTransport->Write(p_data, i_data, m_nRtpPayloadType, pts, 0, isLast);
if (writeSize <= 0)
return 0;
return writeSize;
}
else
{

const int i_count = ( i_data-1 + i_max-2 - 1 ) / (i_max-2);
int i;
p_data++;
i_data--;
for( i = 0; i < i_count; i++ )
{
const int i_payload = (i_data < (i_max-2)) ? i_data : (i_max-2);
const int nalSize = 2 + i_payload;
m_Packet.ExtendBuffer(nalSize);

m_Packet.m_pData[0] = 0x00 | (i_nal_hdr & 0x60) | 28;

m_Packet.m_pData[1] = ( i == 0 ? 0x80 : 0x00 ) | ( (i == i_count-1) ? 0x40 : 0x00 ) | i_nal_type;

memcpy( &m_Packet.m_pData[2], p_data, i_payload );
m_Packet.m_DataSize = nalSize;
//int iWrite = m_pRtpTransport->SetRtpData(m_Packet.m_pData, m_Packet.m_DataSize, pts, isLast && (i == i_count-1));
int iWrite = m_pRtpTransport->Write(m_Packet.m_pData, m_Packet.m_DataSize, m_nRtpPayloadType, pts, 0, isLast && (i == i_count-1));
if (iWrite > 0)
writeSize += iWrite;
i_data -= i_payload;
p_data += i_payload;
}
}
return writeSize;
}
== 这是具体拆法