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Program-specific information (PSI) is metadata about a program (channel) and part of an MPEG transport stream. The PSI data as defined by ISO/IEC 13818-1 (MPEG-2 Part 1: Systems) includes four tables: * PAT (Program Association Table) * CAT (Conditional Access Table) * PMT (Program Map Table) * NIT (Network Information Table) PSI is carried in the form of a table structure. Each table structure is broken into sections and can span multiple transport stream packets. 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 (Program Identifier) 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== 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Program-specific information」の詳細全文を読む スポンサード リンク
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