I dont know on which tag i need to ask this question. I'm currently studying about the ATSC standards for Digital TV broadcasting. I have doubts while going through the contents. In Digital TV broadcasting, a single bandwidth will contain multiple channels(services).
The data that is coded and multiplexed by the broadcaster is called a transport stream.
The transport stream consists of header and payload. The header comprises of PID's of the audio elementary stream or video elementary stream or data elementary stream. This transport stream is received by the set top box containing the middleware which parses the transport stream and puts the data onto the PAT,PMT,EIT,ETT,SDT,NIT,CAT tables..
Is it possible to use PSI tables and not ATSC tables?
This would be like explaining the entire standard in a few sentence, but here it is:
MPEG 2 systems - numbered ISO/IEC 13818-1 defines the structure of packets and timing of how compressed video along with associated information can be transported. Such a stream is called transport stream which is packetized with 188 bytes.
Many audio and video streams can be simultaneously multiplexed. They are identified as PID of the stream. The set of PIDs and the organization of the stream is expressed as PAT and PMT tables. PAT, PMT, and CAT tables are mandatory by MPEG2 system, without which you cannot decode the stream easily. However, apart from this more information is needed that are encoded as other tables, NIT, SDT and EIT.
Before answering your question, i would like to clear some of your doubts which is the cause of confusion.
This transport stream is received by the settop box containing the middleware which parses the tranport stream and put the data on to the PAT,PMT,EIT,ETT,SDT,NIT,CAT tables..
The correct representation is :
This transport stream carries the audio video data and other important tables PAT,PMT,EIT,ETT,SDT,NIT,CAT tables.. this is received by the settop box containing the middleware which parses the tables of tranport stream and decodes the appropriate audio video lines.
Yes, it is possible not to use anything other than PAT PMT and no other table, the transport stream is still fully decodable by STB. These are not ATSC tables. but other tables only makes it easy to put relevant information.
Finally: EPG is not done by mapping the above tables: EPG is simply carried in of the tables called -EIT. It refers to program names (channels) as mentioned in PAT. One of the reference below explains that as well.
I am providing some reference documents for your reference:
1. PSIP: Program specific information
2. PSIP tutorial
3. The ATSC transport layer, including program and system information protocol (PSIP)
4. Using SI Tables to Create Electronic Program Guides
5. ISO/IEC 13818-1 MPEG 2 systems. Read section "2.4.4 Program specific information"
6. SYSTEM INFORMATION FOR DIGITAL TELEVISION ATSC STANDARD.
7. ETSI EN 300 468 - Digital Video Broadcasting (DVB); Specification for Service Information (SI) in DVB systems - Section 5 explains SI information.