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TV Stream Monitor User Manual 1.06
• EIT – Sections with table numbers 0x4E missing in PID 0x0012 for more than 2 seconds.
Sections with numbers other than the range of 0x4E-0x6F or 0x72 found at PID 0x0012.
• The EIT (Event Information Table) describes what is on now and next on each service, and
optionally details the complete programming schedule. The EIT schedule information is only
accessible if the TS is not scrambled.
• RST – Sections with table numbers, other than 0x71 and 0x72, found at PID 0x0013. Two
sections with table numbers 0x71 (RST) at PID 0x0013 for less than 25 milliseconds.
• The RST is a quick updating mechanism for the status information carried in the EIT.
• TDT – Sections with table number 0x70 (TDT) missing at PID 0x0014 for more than 30
seconds. Sections with table number other than 0x70, 0x72 (ST), 0x73 (TOT), found at PID
0x0014. Two sections with table number 0x70 (TDT) at PID 0x0014 for less than 25 milliseconds.
• The TDT carries the current UTC time and date information. In addition to the TDT, a TOT can
be transmitted which gives information about a local time offset in a given area.
-------------------------------------------Conditional Access Alarms (CA)--------------------------------------------
Under the DVB standard, conditional access system (CAS) standards are defined in the
specification documents for DVB-CA (conditional access), DVB-CSA (the common scrambling
algorithm) and DVB-CI (the Common Interface). These standards define a method by which one
can obfuscate a digital-television stream, with access provided only to those with valid
decryption smart-cards. This is achieved by a combination of scrambling and encryption. The
data stream is scrambled with a 48-bit secret key, called the control word. Knowing the value of
the control word at a given moment is of relatively little value, as under normal conditions,
content providers will change the control word several times per minute. The control word is
generated automatically in such a way that successive values are not usually predictable.
In order for the receiver to unscramble the data stream, it must be permanently informed about
the current value of the control word. In practice, it must be informed slightly in advance, so that
no viewing interruption occurs. Encryption is used to protect the control word during
transmission to the receiver: the control word is encrypted as an entitlement control message
(ECM). The CA subsystem in the receiver will decrypt the control word only when authorized to
do so; that authority is sent to the receiver in the form of an entitlement management message
(EMM). The control word can be transmitted through different ECMs at once. This allows the use
of several conditional access systems at the same time.
The contents of ECMs and EMMs are not standardized and as such they depend on the
conditional access system being used.
