Rtmp协议实现

本文主要是介绍Rtmp协议实现，对大家解决编程问题具有一定的参考价值，需要的程序猿们随着小编来一起学习吧！

Rtmp协议看一篇就够了_fdsafwagdagadg6576的专栏-CSDN博客

rtmp 封装h264需要应用层处理, librtmp仅仅负责connect&send

本例实现rtp 流转成rtmp流

 rtmp 协议封包
Rtmp协议看一篇就够了_fdsafwagdagadg6576的专栏-CSDN博客

实现代码

audio

video 
videoheader:

//videoTagHeader
packetBody[iter++] = 0x17; // 1:keyframe  7:AVC
packetBody[iter++] = 0x00; // AVC sequence header
packetBody[iter++] = 0x00;
packetBody[iter++] = 0x00;
packetBody[iter++] = 0x00; // fill in 0;
packetBody[iter++] = 0x01;
unsigned int    nal_len = 0 ;
unsigned char * buf_offset = m_videoHeader->m_SPS->m_pData;
unsigned char * buf = buf_offset ;
int total = m_videoHeader->m_SPS->m_iLen ;
unsigned char   *nal = NULL ;
//videoTagBody
nal = get_nal1( &nal_len, &buf_offset, buf, total, p->static_inaluHeaderLen ) ;
{
VideoCtlData * pItem = m_videoHeader->m_SPS ;
if ( pItem->m_iLen >= 4 )
{
	packetBody[iter++] = nal[1] ;
	packetBody[iter++] = nal[2] ;
	packetBody[iter++] = nal[3] ;
}
}
packetBody[iter++] = 0xFF ;
packetBody[iter++] = 0xE0 | ( 0x1F & m_videoHeader->m_iSPSNumber ) ;
if ( m_videoHeader->m_SPS != NULL )
{
packetBody[iter++] = nal_len >> 8 ;
packetBody[iter++] = nal_len & 0xFF ;
memcpy( &packetBody[iter], nal, nal_len ) ;
iter += nal_len ;
}
packetBody[iter++] = m_videoHeader->m_iPPSNumber ;  //PPS Header
if ( m_videoHeader->m_PPS != NULL )
{
packetBody[iter++] = ( m_videoHeader->m_PPS->m_iLen - p->static_inaluHeaderLen ) >> 8 ;
packetBody[iter++] = ( m_videoHeader->m_PPS->m_iLen - p->static_inaluHeaderLen ) & 0xFF ;
memcpy( &packetBody[iter], m_videoHeader->m_PPS->m_pData + p->static_inaluHeaderLen, m_videoHeader->m_PPS->m_iLen - p->static_inaluHeaderLen ) ;
iter += m_videoHeader->m_PPS->m_iLen - p->static_inaluHeaderLen ;
}

videodata

int  _send_video_data_toserver( janus_videoroom_participant *p, PushItemData *videoItem )
{
            int ibegain = ( DATA_HEADER_SIZE - 5 ) ; //0x00000001+type is 5 byte
            //tag data第一个字节0x17固定
            unsigned char *packetBody = videoItem->m_dataPtr + ibegain;
            int iter = 0 ;
            if ( videoItem->m_bKeyFrame )
            {
                packetBody[iter++] = 0x17;
            }
            else
            {
                packetBody[iter++] = 0x27 ;
            }
		.....
            AssembleNaluData( p, videoItem->m_dataPtr + DATA_HEADER_SIZE, videoItem->m_dwSize ) ;
            iRet = _send_Rtmp_packet(...);
}
//VideoTagBody
gboolean AssembleNaluData( janus_videoroom_participant *p, unsigned char *pNaluData, int iLen )
{
      while( ( nal = get_nal1( &nal_len, &buf_offset, buf, total, p->static_inaluHeaderLen ) ) != NULL )  {
            offset = write_nal_len;
			//nal len +nal data
                pNaluData[offset++] = ( uint8_t )( ( nal_len >> 24 ) & 0x7f ); //nal length
                pNaluData[offset++] = ( uint8_t )( ( nal_len >> 16 ) & 0xff ); //nal length
                pNaluData[offset++] = ( uint8_t )( ( nal_len >> 8 ) & 0xff ); //nal length
                pNaluData[offset++] = ( uint8_t )( nal_len & 0xff ); //nal length
                write_nal_len += nal_len + p->static_inaluHeaderLen ;
        }
      
}

发送

//调用librtmp发送
int  _send_Rtmp_packet( janus_videoroom_participant *p, unsigned int packetType, unsigned char *data, unsigned int size, uint32_t nTimeStamp )
{
    guint64 janus_session_id = 0;
	//一个RTMPPacket对应RTMP协议规范里面的一个块（Chunk）
    RTMPPacket packet;
    RTMPPacket_Reset( &packet );
	/*  Chunk Basic Header: HeaderType+ChannelID组成  1个字节
	 *     >HeaderType(前两bit): 00->12字节  01->8字节
	 *     >ChannelID(后6个bit): 02->Ping和ByteRead通道 03->Invoke通道 connect() publish()和自己写的NetConnection.Call() 04->Audio和Vidio通道
	 *  12字节举例
	 *  Chunk Message Header: timestamp + message_length+message_typ + msg_stream_id */
	//rtmp chunk header;	
    packet.m_packetType = packetType;
    packet.m_nChannel = 0x04;  //audio or video
    packet.m_headerType = RTMP_PACKET_SIZE_LARGE;
    packet.m_nTimeStamp = nTimeStamp;
    packet.m_nInfoField2 = p->m_pub_rtmp.m_stream_id ;
    packet.m_nBodySize = size;
    packet.m_body = ( char* )( data + RTMP_MAX_HEADER_SIZE ) ;
	//librtmp send interface; 应该是librtmp自动添加了basic header,messge handle etc
    int iRet = RTMP_SendPacket( &p->m_pub_rtmp, &packet, 0 ) ;
	....
}

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