Program-specific information
Program-specific information is metadata about a program and part of an MPEG transport stream.
The PSI data as defined by ISO/IEC 13818-1 includes four tables:
- PAT
- CAT
- PMT
- NIT
PSI is carried in the form of a table structure. Each table structure is broken into sections. Each section can span multiple transport stream packets. On the other hand, a transport stream packet can also contain multiple sections with same PID. Adaptation field also occurs in TS packets carrying PSI data. The PSI data will never be scrambled so that the decoder at the receiving end can easily identify the properties of the stream.
The sections comprising the PAT and CAT tables are associated with predefined PIDs as explained in their respective descriptions below. There may be multiple independent PMT sections in a stream; each section is given a unique user-defined PID and maps a program number to the metadata describing that program and the streams within it. PMT section PIDs are defined in the PAT, and are the only PIDs defined there. The streams themselves are contained in PES packets with user-defined PIDs specified in the PMT.
PSI structure
Table Sections
| Name | Number of bits | Description |
| Table ID | 8 | Table Identifier, that defines the structure of the syntax section and other contained data. As an exception, if this is the byte that immediately follow previous table section and is set to 0xFF, then it indicates that the repeat of table section end here and the rest of TS packet payload shall be stuffed with 0xFF. Consequently, the value 0xFF shall not be used for the Table Identifier. |
| Section syntax indicator | 1 | A flag that indicates if the syntax section follows the section length. The PAT, PMT, and CAT all set this to 1. |
| Private bit | 1 | The PAT, PMT, and CAT all set this to 0. Other tables set this to 1. |
| Reserved bits | 2 | Set to 0x03 |
| Section length unused bits | 2 | Set to 0 |
| Section length | 10 | The number of bytes that follow for the syntax section and/or table data. These bytes must not exceed a value of 1021. |
| Syntax section/Table data | N*8 | When the section length is non-zero, this is the section length number of syntax and data bytes. |
Descriptor
PAT
The program association table lists all programs available in the transport stream. Each of the listed programs is identified by a 16-bit value called program_number. Each of the programs listed in PAT has an associated value of PID for its PMT.The value 0x0000 for program_number is reserved to specify the PID where to look for network information table. If such a program is not present in PAT the default PID value shall be used for NIT.
TS packets containing PAT information always have PID 0x0000.
| Name | Number of bits | Description |
| Program num | 16 | Relates to the Table ID extension in the associated PMT. A value of 0 is reserved for a NIT packet identifier. |
| Reserved bits | 3 | Set to 0x07 |
| Program map PID | 13 | The packet identifier that contains the associated PMT |
The PAT is assigned PID 0x0000 and table id of 0x00. The transport stream contains at least one or more TS packets with PID 0x0000. Some of these consecutive packets form the PAT.
At the decoder side the PSI listens to the incoming TS packets. After the filter identifies the PAT table they assemble the packet and decode it.
A PAT has information about all the programs contained in the TS. The PAT contains information showing the association of Program Map Table PID and Program Number.
The PAT should end with a 32-bit CRC
PMT (Program map specific data)
PMTs contain information about programs. For each program, there is one PMT. While the MPEG-2 standard permits more than one PMT section to be transmitted on a single PID, most MPEG-2 "users" such as ATSC and SCTE require each PMT to be transmitted on a separate PID that is not used for any other packets.The PMTs provide information on each program present in the transport stream, including the program_number, and list the elementary streams that comprise the described MPEG-2 program. There are also locations for optional descriptors that describe the entire MPEG-2 program, as well as an optional descriptor for each elementary stream. Each elementary stream is labeled with a stream_type value.
| Name | Number of bits | Description |
| Reserved bits | 3 | Set to 0x07 |
| PCR PID | 13 | The packet identifier that contains the program clock reference used to improve the random access accuracy of the stream's timing that is derived from the program timestamp. If this is unused. then it is set to 0x1FFF. |
| Reserved bits | 4 | Set to 0x0F |
| Program info length unused bits | 2 | Set to 0 |
| Program info length | 10 | The number of bytes that follow for the program descriptors. |
| Program descriptors | N*8 | When the program info length is non-zero, this is the program info length number of program descriptor bytes. |
| Elementary stream info data | N*8 | The streams used in this program map. |
| Name | Number of bits | Description |
| stream type | 8 | This defines the structure of the data contained within the elementary packet identifier. |
| Reserved bits | 3 | Set to 0x07 |
| Elementary PID | 13 | The packet identifier that contains the stream type data. |
| Reserved bits | 4 | Set to 0x0F |
| ES Info length unused bits | 2 | Set to 0 |
| ES Info length length | 10 | The number of bytes that follow for the elementary stream descriptors. |
| Elementary stream descriptors | N*8 | When the ES info length is non-zero, this is the ES info length number of elementary stream descriptor bytes. |
This table contains PID numbers of elementary streams associated with the program and it has information about the type of these elementary streams.
In addition it may also contain an ECM stream for any other stream that is encrypted. These messages provide the information used in the cipher key selection stage.
CAT (Conditional access specific data)
- Table ID value is 0x01.
NIT (network information specific data)
This optional table may group transport stream identifiers into a network, providing access parameters and other details. ITU-T Rec. H.222 and ISO/IEC 13818-1 do not define the NIT structure. The European Broadcasting Union DVB specification ETSI EN 300 468 does. The purpose of mentioning but not defining this table in H.222 is that it has reserved program number 0 in the PAT. The Table ID extension is used to identify the local network together with a directory listing of transport streams. Descriptors are used to list the modulation, source of those streams and programs. The original network identifier is meant to allow transport streams and programs on foreign networks to be included in the local network which allows no remapping of transport and program IDs that may be duplicated between networks. The DVB specification defines the transport packet identifier as 16 and the table identifier of the local network of transports as 64. A table identifier of 65 is for a foreign network of transports. The network identifiers are maintained via who have separated the identifiers into two unique, yet unnecessary groupings of Network_ID and Original_Network_ID. The two groupings have a large number of overlapping entries.PSI labels
Table Identifiers
Each table in a transport stream is identified by an 8-bit table identifier.| Decimal | Hexadecimal | Description |
| 0 | 0x00 | Program Association section contains a directory listing of all Program Map Tables |
| 1 | 0x01 | Conditional Access section contains a directory listing of all EMM streams |
| 2 | 0x02 | Program Map section contains a directory listing of all elementary streams. |
| 3 | 0x03 | Transport Stream Description section. |
| 4 | 0x04 | ISO/IEC 14496 scene description section. |
| 5 | 0x05 | ISO/IEC 14496 object description section. |
| 6 | 0x06 | Metadata section. |
| 7 | 0x07 | ISO/IEC 13818-11 IPMP control information. |
| 8 - 57 | 0x08 - 0x39 | Reserved. |
| 58 | 0x3A | ISO/IEC 13818-6 DSM CC multiprotocol encapsulated. |
| 59 | 0x3B | ISO/IEC 13818-6 DSM CC U-N messages. |
| 60 | 0x3C | ISO/IEC 13818-6 DSM CC Download Data Messages. |
| 61 | 0x3D | ISO/IEC 13818-6 DSM CC stream descriptor list. |
| 62 | 0x3E | ISO/IEC 13818-6 DSM CC privately defined. |
| 63 | 0x3F | ISO/IEC 13818-6 DSM CC addressable. |
| 64 - 127 | 0x40 - 0x7F | Used by DVB. |
| 128 - 143 | 0x80 - 0x8F | DVB-CSA and DigiCipher II/ATSC CA message sections used in EMM and ECM streams. |
| 144 - 191 | 0x90 - 0xBF | May be assigned as needed to other data tables. |
| 192 - 254 | 0xC0 - 0xFE | Used by DigiCipher II/ATSC/SCTE. |
| 255 | 0xFF | Forbidden. As is used for null padding. |
SCTE Specific tables:
0xCO table id is used by Programme Information Message
0xC1 table id is used by Programme Name Message
It is not necessary that pid of PMT pointed by PAT will contain a table with table id 0x02
Ignoring table id while reading PMT could have bad consequence
Program and Elementary Stream Descriptor Tags
Each descriptor in a transport stream table is identified by an 8-bit descriptor tag.| Decimal | Hexadecimal | Description |
| 0 - 1 | 0x00 - 0x01 | Reserved. |
| 2 | 0x02 | Video stream header parameters for ITU-T Rec. H.262, ISO/IEC 13818-2 and ISO/IEC 11172-2 |
| 3 | 0x03 | Audio stream header parameters for ISO/IEC 13818-3 and ISO/IEC 11172-3 |
| 4 | 0x04 | Hierarchy for stream selection |
| 5 | 0x05 | Registration of private formats |
| 6 | 0x06 | Data stream alignment for packetized video and audio sync point |
| 7 | 0x07 | Target background grid defines total display area size |
| 8 | 0x08 | Video Window defines position in display area |
| 9 | 0x09 | Conditional access system and EMM/ECM PID |
| 10 | 0x0A | ISO 639 language and audio type |
| 11 | 0x0B | System clock external reference |
| 12 | 0x0C | Multiplex buffer utilization bounds |
| 13 | 0x0D | Copyright identification system and reference |
| 14 | 0x0E | Maximum bit rate |
| 15 | 0x0F | Private data indicator |
| 16 | 0x10 | Smoothing buffer |
| 17 | 0x11 | STD video buffer leak control |
| 18 | 0x12 | IBP video I-frame indicator |
| 19 | 0x13 | ISO/IEC13818-6 DSM CC carousel identifier |
| 20 | 0x14 | ISO/IEC13818-6 DSM CC association tag |
| 21 | 0x15 | ISO/IEC13818-6 DSM CC deferred association tag |
| 22 | 0x16 | ISO/IEC13818-6 DSM CC Reserved. |
| 23 | 0x17 | DSM CC NPT reference |
| 24 | 0x18 | DSM CC NPT endpoint |
| 25 | 0x19 | DSM CC stream mode |
| 26 | 0x1A | DSM CC stream event |
| 27 | 0x1B | Video stream header parameters for ISO/IEC 14496-2 |
| 28 | 0x1C | Audio stream header parameters for ISO/IEC 14496-3 |
| 29 | 0x1D | IOD parameters for ISO/IEC 14496-1 |
| 30 | 0x1E | SL parameters for ISO/IEC 14496-1 |
| 31 | 0x1F | FMC parameters for ISO/IEC 14496-1 |
| 32 | 0x20 | External ES identifier for ISO/IEC 14496-1 |
| 33 | 0x21 | MuxCode for ISO/IEC 14496-1 |
| 34 | 0x22 | FMX Buffer Size for ISO/IEC 14496-1 |
| 35 | 0x23 | Multiplex Buffer for ISO/IEC 14496-1 |
| 36 | 0x24 | Content labeling for ISO/IEC 14496-1 |
| 37 | 0x25 | Metadata pointer |
| 38 | 0x26 | Metadata |
| 39 | 0x27 | Metadata STD |
| 40 | 0x28 | Video stream header parameters for ITU-T Rec. H.264 and ISO/IEC 14496-10 |
| 41 | 0x29 | ISO/IEC 13818-11 IPMP |
| 42 | 0x2A | Timing and HRD for ITU-T Rec. H.264 and ISO/IEC 14496-10 |
| 43 | 0x2B | Audio stream header parameters for ISO/IEC 13818-7 ADTS AAC |
| 44 | 0x2C | FlexMux Timing for ISO/IEC 14496-1 |
| 45 | 0x2D | Text stream header parameters for ISO/IEC 14496 |
| 46 | 0x2E | Audio extension stream header parameters for ISO/IEC 14496-3 |
| 47 | 0x2F | Video auxiliary stream header parameters |
| 48 | 0x30 | Video scalable stream header parameters |
| 49 | 0x31 | Video multi stream header parameters |
| 50 | 0x32 | Video stream header parameters for ITU-T Rec. T.800 and ISO/IEC 15444 |
| 51 | 0x33 | Video multi operation point stream header parameters |
| 52 | 0x34 | Video stereoscopic stream header parameters for ITU-T Rec. H.262, ISO/IEC 13818-2 and ISO/IEC 11172-2 |
| 53 | 0x35 | Program stereoscopic information |
| 54 | 0x36 | Video stereoscopic information |
| 55 - 63 | 0x37 - 0x3F | Reserved. |
| 64 - 127 | 0x40 - 0x7F | Used by DVB. |
| 128 - 207 | 0x80 - 0xCF | Used by ATSC. |
| 160 | 0xA0 | VideoLAN FourCC, video size and codec initialization data |
| 208 - 223 | 0xD0 - 0xDF | Used by ISDB. |
| 224 - 233 | 0xE0 - 0xE9 | Used by CableLabs. |
| 234 - 254 | 0xEA - 0xFE | May be assigned as needed to other descriptors. |
| 255 | 0xFF | Forbidden. As is used for null padding. |
Elementary stream types
Each elementary stream in a transport stream is identified by an 8-bit elementary stream type assignment.| Decimal | Hexadecimal | Description |
| 0 | 0x00 | Reserved |
| 1 | 0x01 | ISO/IEC 11172-2 in a packetized stream |
| 2 | 0x02 | ITU-T Rec. H.262 and ISO/IEC 13818-2 in a packetized stream |
| 3 | 0x03 | ISO/IEC 11172-3 in a packetized stream |
| 4 | 0x04 | ISO/IEC 13818-3 in a packetized stream |
| 5 | 0x05 | ITU-T Rec. H.222 and ISO/IEC 13818-1 privately defined |
| 6 | 0x06 | ITU-T Rec. H.222 and ISO/IEC 13818-1 privately defined |
| 7 | 0x07 | ISO/IEC 13522 in a packetized stream |
| 8 | 0x08 | ITU-T Rec. H.222 and ISO/IEC 13818-1 DSM CC in a packetized stream |
| 9 | 0x09 | ITU-T Rec. H.222 and ISO/IEC 13818-1/11172-1 auxiliary data in a packetized stream |
| 10 | 0x0A | ISO/IEC 13818-6 DSM CC multiprotocol encapsulation |
| 11 | 0x0B | ISO/IEC 13818-6 DSM CC U-N messages |
| 12 | 0x0C | ISO/IEC 13818-6 DSM CC stream descriptors |
| 13 | 0x0D | ISO/IEC 13818-6 DSM CC tabled data |
| 14 | 0x0E | ISO/IEC 13818-1 auxiliary data in a packetized stream |
| 15 | 0x0F | ISO/IEC 13818-7 ADTS AAC in a packetized stream |
| 16 | 0x10 | ISO/IEC 14496-2 in a packetized stream |
| 17 | 0x11 | ISO/IEC 14496-3 in a packetized stream |
| 18 | 0x12 | ISO/IEC 14496-1 in a packetized stream |
| 19 | 0x13 | ISO/IEC 14496-1 in ISO/IEC 14496 tables |
| 20 | 0x14 | ISO/IEC 13818-6 DSM CC synchronized download protocol |
| 21 | 0x15 | Packetized metadata |
| 22 | 0x16 | Sectioned metadata |
| 23 | 0x17 | ISO/IEC 13818-6 DSM CC Data Carousel metadata |
| 24 | 0x18 | ISO/IEC 13818-6 DSM CC Object Carousel metadata |
| 25 | 0x19 | ISO/IEC 13818-6 Synchronized Download Protocol metadata |
| 26 | 0x1A | ISO/IEC 13818-11 IPMP |
| 27 | 0x1B | ITU-T Rec. H.264 and ISO/IEC 14496-10 in a packetized stream |
| 28 | 0x1C | ISO/IEC 14496-3 in a packetized stream |
| 29 | 0x1D | ISO/IEC 14496-17 in a packetized stream |
| 30 | 0x1E | ISO/IEC 23002-3 in a packetized stream |
| 31 | 0x1F | ISO/IEC 14496-10 SVC in a packetized stream |
| 32 | 0x20 | ISO/IEC 14496-10 MVC in a packetized stream |
| 33 | 0x21 | ITU-T Rec. T.800 and ISO/IEC 15444 in a packetized stream |
| 34 - 35 | 0x22 - 0x23 | Reserved. |
| 36 | 0x24 | ITU-T Rec. H.265 and ISO/IEC 23008-2 in a packetized stream |
| 37 - 65 | 0x25 - 0x41 | Reserved. |
| 66 | 0x42 | Chinese Video Standard in a packetized stream |
| 67 - 126 | 0x43 - 0x7e | Reserved. |
| 127 | 0x7f | ISO/IEC 13818-11 IPMP in a packetized stream |
| 128 | 0x80 | ITU-T Rec. H.262 and ISO/IEC 13818-2 with DES-64-CBC encryption for DigiCipher II or PCM audio for Blu-ray in a packetized stream |
| 129 | 0x81 | Dolby Digital up to six channel audio for ATSC and Blu-ray in a packetized stream |
| 130 | 0x82 | SCTE subtitle or DTS 6 channel audio for Blu-ray in a packetized stream |
| 131 | 0x83 | Dolby TrueHD lossless audio for Blu-ray in a packetized stream |
| 132 | 0x84 | Dolby Digital Plus up to 16 channel audio for Blu-ray in a packetized stream |
| 133 | 0x85 | DTS 8 channel audio for Blu-ray in a packetized stream |
| 134 | 0x86 | SCTE-35 digital program insertion cue message or DTS 8 channel lossless audio for Blu-ray in a packetized stream |
| 135 | 0x87 | Dolby Digital Plus up to 16 channel audio for ATSC in a packetized stream |
| 136 - 143 | 0x88 - 0x8F | Privately defined. |
| 144 | 0x90 | Blu-ray Presentation Graphic Stream in a packetized stream |
| 145 | 0x91 | ATSC DSM CC Network Resources table |
| 146 - 191 | 0x92 - 0xBF | Privately defined. |
| 192 | 0xC0 | DigiCipher II text in a packetized stream |
| 193 | 0xC1 | Dolby Digital up to six channel audio with AES-128-CBC data encryption in a packetized stream |
| 194 | 0xC2 | ATSC DSM CC synchronous data or Dolby Digital Plus up to 16 channel audio with AES-128-CBC data encryption in a packetized stream |
| 195 - 206 | 0xC3 - 0xCE | Privately defined. |
| 207 | 0xCF | ISO/IEC 13818-7 ADTS AAC with AES-128-CBC frame encryption in a packetized stream |
| 208 | 0xD0 | Privately defined. |
| 209 | 0xD1 | BBC Dirac in a packetized stream |
| 210 - 218 | 0xD2 - 0xDA | Privately defined. |
| 219 | 0xDB | ITU-T Rec. H.264 and ISO/IEC 14496-10 with AES-128-CBC slice encryption in a packetized stream |
| 220 - 233 | 0xDC - 0xE9 | Privately defined. |
| 234 | 0xEA | Microsoft Windows Media Video 9 in a packetized stream |
| 235 - 255 | 0xEB - 0xFF | Privately defined. |