From: "Nico" <[EMAIL PROTECTED]> > 1) read the PAT to find the list of programs ids > 2) read the PMT to find the list of ES streams (audio/video/teletext/subs) > associated to a given program id > > Is it correct?
Yes, but this is only ISO-MPEG2. > Now I wonder > 3) what's the use of NIT and SDT? Those are the extensions that DVB makes to ISO-MPEG2. It defines additional tables and "abstracts" the information from MPEG-2. While MPEG-2 only knows "programs" and refers to them by "program numbers", DVB calls these things "services" and refers to them by service identifiers (SIDs). MPEG-2 has no means to specify a transport stream (multiplex), DVB introduces the Original Network Identifier (ONID) and the Transport Stream Identifier (TSID) to address a stream. So in DVB you can fully address a service with an ONID:TSID:SID triple. ONID:TSID uniquely identifies a transport stream. The required tuning information for each ONID:TSID is transmitted in the DVB NIT (Network Information Tables). The services (SIDs) for each transport stream are described in the SDTs, including e.g. broadcaster, network and channel name. AFAIK, MPEG-2 has no means to transmit such information. Consider MPEG-2 as only a _base_ for a digital broadcasting system, which _needs_ to be extended to become a fully functional system. Two such extensions are ATSC (North America) and DVB (Europe), of which DVB appears to be the more complex and powerful one. Regards, -- Robert Schlabbach e-mail: [EMAIL PROTECTED] Berlin, Germany -- Info: To unsubscribe send a mail to [EMAIL PROTECTED] with "unsubscribe linux-dvb" as subject.
