[转载]TS流之PMT结构（转）
2014-01-11 15:36阅读：
PMT结构定义：
typedef struct TS_PMT_Stream
{
unsigned stream_type
: 8;
//指示特定PID的节目元素包的类型。该处PID由elementary PID指定
unsigned elementary_PID
: 13;
//该域指示TS包的PID值。这些TS包含有相关的节目元素
unsigned ES_info_length
: 12;
//前两位bit为00。该域指示跟随其后的描述相关节目元素的byte数
unsigned descriptor;
}TS_PMT_Stream; //--------
//PMT 表结构体
typedef struct TS_PMT
{
unsigned table_id
: 8; //固定为0x02, 表示PMT表
--------byte: 1-------------
unsigned section_syntax_indicator
: 1;
//固定为0x01
unsigned zero
:
1; //0x01
unsigned reserved_1
: 2; //0x03
unsigned section_length :
12;//首先两位bit置为00，它指示段的byte数，由段长度域开始，包含CRC。
--------byte: 4-------------
unsigned program_number
: 16;// 指出该节目对应于可应用的Program map PID
--------byte: 6-------------
unsigned reserved_2
: 2; //0x03
unsigned version_number
: 5; //指出TS流中Program map section的版本号
unsigned current_next_indicator
: 1;
//当该位置1时，当前传送的Program map section可用；
--------byte: 7-------------
//当该位置0时，指示当前传送的Program map
section不可用，下一个TS流的Program map section有效。
unsigned section_number
: 8; //固定为0x00
unsigned last_section_number
: 8; //固定为0x00
--------byte: 9-------------
unsigned reserved_3
: 3; //0x07
unsigned PCR_PID
: 13;
//指明TS包的PID值，该TS包含有PCR域，
//该PCR值对应于由节目号指定的对应节目。
//如果对于私有数据流的节目定义与PCR无关，这个域的值将为0x1FFF。
--------byte: 11-------------
unsigned reserved_4
: 4; //预留为0x0F
unsigned program_info_length
: 12; //前两位bit为00。该域指出跟随其后对节目信息的描述的byte数。
--------byte:
13-------------
std::vector<TS_PMT_Stream> PMT_Stream;
//每个元素包含8位, 指示特定PID的节目元素包的类型。该处PID由elementary PID指定
unsigned reserved_5
: 3; //0x07
unsigned reserved_6
: 4; //0x0F
------single: 5 Bytes---------
unsigned CRC_32
:
32;
} TS_PMT;
解析代码为：
HRESULT CTS_Stream_Parse::adjust_PMT_table ( TS_PMT * packet,
unsigned char * buffer )
{
packet->table_id
=
buffer[0];
packet->section_syntax_indicator
= buffer[1] >> 7;
packet->zero
= buffer[1] >> 6 &
0x01;
packet->reserved_1
= buffer[1] >> 4 & 0x03;
packet->section_length
= (buffer[1] & 0x0F)
<< 8 | buffer[2];
packet->program_number
= 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];
packet->reserved_3
= buffer[8] >> 5;
packet->PCR_PID
= ((buffer[8] << 8) |
buffer[9]) & 0x1FFF;
PCRID = packet->PCR_PID;
packet->reserved_4
= buffer[10] >> 4;
packet->program_info_length
= (buffer[10] & 0x0F) << 8 |
buffer[11];
// Get CRC_32
int len = 0;
len = packet->section_length + 3;
packet->CRC_32
= (buffer[len-4] & 0x000000FF)
<< 24
| (buffer[len-3] & 0x000000FF) << 16
| (buffer[len-2] & 0x000000FF) << 8
| (buffer[len-1] & 0x000000FF);
int pos = 12;
// program info descriptor
if ( packet->program_info_length != 0
)
pos +=
packet->program_info_length;
// Get stream type and PID
for ( ; pos <=
(packet->section_length + 2 ) - 4; )
{
TS_PMT_Stream pmt_stream;
pmt_stream.stream_type =
buffer[pos];
packet->reserved_5 =
buffer[pos+1] >> 5;
pmt_stream.elementary_PID =
((buffer[pos+1] << 8) | buffer[pos+2]) &
0x1FFF;
packet->reserved_6
= buffer[pos+3] >> 4;
pmt_stream.ES_info_length =
(buffer[pos+3] & 0x0F) << 8 | buffer[pos+4];
pmt_stream.descriptor = 0x00;
if (pmt_stream.ES_info_length != 0)
{
pmt_stream.descriptor = buffer[pos +
5];
for( int len = 2; len <=
pmt_stream.ES_info_length; len ++ )
{
pmt_stream.descriptor =
pmt_stream.descriptor<< 8 | buffer[pos + 4 + len];
}
pos += pmt_stream.ES_info_length;
}
pos += 5;
packet->PMT_Stream.push_back( pmt_stream );
TS_Stream_type.push_back( pmt_stream );
}
return 0;
}
举例如下：
0x47 0x43 0xe8 0x12 0x00 0x02 0xb0 0x12 0x00 0x01 0xc1 0x00 0x00
0xe3 0xe9 0xf0 0x00 0x1b 0xe3 0xe9 0xf0 0x00
0xf0 0xaf 0xb4 0x4f 0xff 0xff 0xff 0xff 0xff 0xff 0xff 0xff 0xff
0xff 0xff 0xff 0xff 0xff 0xff 0xff 0xff 0xff 0xff 0xff 0xff 0xff
0xff 0xff 0xff
