Annex C - Multiplex and Transport
Not all constraints on MPEG are mentioned here or fully explained. See the ATSC standards document A/53 for details.
In MPEG, PTS (or DTS) is entered in the bitstream at intervals not exceeding 700 mS. ATSC further constrains PTS (or DTS) to be inserted at the beginning of each access unit.
Note: A/53 Annex C originally specified a "Program Paradigm" in which the PIDs for the PMT, video, PCR, audio, and data of a program held a fixed relationship to each other (offsets of 0x0000, 0x0001, 0x0001, 0x0004, and 0x000A, respectively). The "Program Paradigm" has been removed in recent revisions of A/53.
Maximum span between occurrences of the PMT for television service is 400 ms.
Maximum span between occurrences of section 0 of the PAT for television service is 100 ms.
Each PES packet begins with a video access unit, aligned with the PES packet header.
A/53 does not include portions of MPEG relating to still pictures.
Conceptually, the ATSC output transport stream is a continuous MPEG transport stream with rate
2x(188/208)(312/313)(684/286)(4.5) Mbps
or twice that rate for 16 VSB.
The symbol rate is defined as (684/286)x4.5 Msymbols/s
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