Deviser S7200 User Manual page 65

(4) Continuity_count_error: Each transport stream packet contains a 4-byte-long header, a 4-bit counter
which counts from 0 to 15 in a loop, and then begins at zero again after an overflow (modulo 16
counter). However, each transport stream packet for each PID has its own continuity counter, i.e.
packets with a PID=100, e.g., have a different counter, as do packets with a PID=200. This counter helps
recognize missing or repeated transport stream packets of the same PID in order to draw attention to
any multiplexer problems.
Such problems can also arise as a result of errors in remultiplexing or due to random bit errors in the
transmission link. Although MPEG-2 allows discontinuities in the transport stream, they must be indicated
in the adaptation field, e.g. after a switch-over (discontinuity indicator=1). In the case of zero packets
(PID=0x1FF), discontinuities are allowed and are not verified.
A continuity_error occurs when
 The same TS packet is transmitted twice without a discontinuity being indicated,
 A packet is missing (count incremented by 2) without a discontinuity being indicated, or
 The sequence of packets is wrong.
(5) PMT_error: For each program, a Program Map Table (PMT) is transmitted at maximum intervals of 500 ms.
The PIDs of the MAPs are listed in the PAT. The PMT contains the respective PIDs of all elementary streams
belonging to this program. If a PMT referenced in the PAT is missing, the set top box or decoder will be
unable to demultiplex or decode them. If a PMT is listed in the PAT but is either missing, errored or
scrambled, will lead to the error message "PMT_error".
A "PMT error" occurs when
 A PMT listed in the PAT is missing,
 A section of the PMT is not repeated after 500 ms or less,
 A PMT is scrambled, or
 The table ID is not 2.
(6) PID_error: The PIDs of all elementary streams of a given program are contained in the associated
program map table (PMT). The PIDs are pointers to the elementary streams: they are used to access the
corresponding packets of the elementary stream to be decoded. If a PID is listed in a PMT but not
contained in the transport stream, the decoder cannot access the corresponding elementary stream.
A "PID_error" occurs when
 Transport stream packets with a PID referenced in a PMT are not contained in the stream, or
 Their repetition rate exceeds a user-definable limit (usually 500 ms or less).
Part II: Settings and Measurements
65