TS流解析之PAT表格解析

//PAT表格定义如下：typedef struct TS_PAT_Program{    unsigned program_number    :16;//节目号    unsigned program_map_PID   :13;//节目映射表的PID，节目号大于0时对应的PID，每个节目对应一个}TS_PAT_Program;//PAT表结构体typedef struct TS_PAT{unsigned table_id: 8; //固定为0x00 ，标志是该表是PATunsigned section_syntax_indicator: 1; //段语法标志位，固定为1unsigned zero: 1; //0unsigned reserved_1: 2; // 保留位unsigned section_length: 12; //表示这个字节后面有用的字节数，包括CRC32unsigned transport_stream_id: 16; //该传输流的ID，区别于一个网络中其它多路复用的流unsigned reserved_2: 2;// 保留位unsigned version_number: 5; //范围0-31，表示PAT的版本号unsigned current_next_indicator: 1; //发送的PAT是当前有效还是下一个PAT有效unsigned section_number: 8; //分段的号码。PAT可能分为多段传输，第一段为00，以后每个分段加1，最多可能有256个分段unsigned last_section_number: 8;  //最后一个分段的号码std::vector<TS_PAT_Program> program;unsigned reserved_3: 3; // 保留位unsigned network_PID: 13; //网络信息表（NIT）的PID,节目号为0时对应的PID为network_PIDunsigned CRC_32: 32;  //CRC32校验码} TS_PAT;//解析代码如下：HRESULT CTS_Stream_Parse::adjust_PAT_table( TS_PAT * packet, unsigned char * buffer){    packet->table_id= buffer[0];    packet->section_syntax_indicator= buffer[1] >> 7;    packet->zero= buffer[1] >> 6 & 0x1;    packet->reserved_1= buffer[1] >> 4 & 0x3;    packet->section_length= (buffer[1] & 0x0F) << 8 | buffer[2];    packet->transport_stream_id= buffer[3] << 8 | buffer[4];    packet->reserved_2= buffer[5] >> 6;    packet->version_number= buffer[5] >> 1 &  0x1F;    packet->current_next_indicator= (buffer[5] << 7) >> 7;    packet->section_number= buffer[6];    packet->last_section_number= buffer[7];    int len= 0;    len= 3 + packet->section_length;    packet->CRC_32                        = (buffer[len-4] & 0x000000FF) << 24    | (buffer[len-3] & 0x000000FF) << 16    | (buffer[len-2] & 0x000000FF) << 8    | (buffer[len-1] & 0x000000FF);    int n = 0;    for ( n = 0; n < packet->section_length - 12; n += 4 )    {        unsigned  program_num = buffer[8 + n ] << 8 | buffer[9 + n ];        packet->reserved_3                = buffer[10 + n ] >> 5;        packet->network_PID = 0x00;        if ( program_num == 0x00)        {            packet->network_PID = (buffer[10 + n ] & 0x1F) << 8 | buffer[11 + n ];            TS_network_Pid = packet->network_PID; //记录该TS流的网络PID            TRACE(" packet->network_PID %0x \n\n", packet->network_PID );        }        else        {            TS_PAT_Program PAT_program;            PAT_program.program_map_PID = (buffer[10 + n] & 0x1F) << 8 | buffer[11 + n];            PAT_program.program_number = program_num;            packet->program.push_back( PAT_program );            TS_program.push_back( PAT_program );//向全局PAT节目数组中添加PAT节目信息        }    }    return 0;}//因此，PAT数据解析结果如下：//PAT数据int printPAT(){print("table_id：0x00// 8section_syntax_indicator：0x01// 1'0'：0x00// 1reserved: 0x03// 2section_length：0x00d// 12transport_stream_id：0x0000// 16reserved：0x03// 2version_number：0x00// 5current_next_indicator：0x01// 1section_number              ：0x00// 8last_section_number         ：0x00// 8program_number：0x0001// 16reserved：0x07// 3program_map_PID：0x03e8// 13CRC：0x f0 0b d7 79");return 0;}

由解析结构可知，该PAT表格中没有网络信息包信息，只包含一个节目，其PID为0x03e8