Type 0 Extension 6 - mattpascoe135/dab GitHub Wiki
The Service linking information feature provides service linking information for use when services carry the same primary service component (hard link) or when the primary service components are related (soft link). The feature is encoded in extension 6 of FIG type 0 (FIG 0/6). Figure 65 shows the structure of the service linking field which is part of the Type 0 field (see also figure 4).
This feature shall use the SIV signalling (see clause 5.2.2.1). The database shall be divided by use of a database key. Changes to the database shall be signalled using the CEI.
The following definitions apply:
###Id (Identifier) list flag: this 1-bit flag shall indicate whether the Id list, together with the preceding byte, is present or not, as follows:
`0: Id list and the preceding byte absent;`
`1: Id list and the preceding byte present.`
###LA (Linkage Actuator): this 1-bit flag shall indicate whether the link is active or inactive (potential), as follows:
`0: potential future link or de-activated link;`
`1: active link.`
###S/H (Soft/Hard): this 1-bit flag shall indicate whether the link is soft or hard, as follows:
`0: Soft link (related services);`
`1: Hard link (services carrying the same primary service component).`
###ILS (International linkage set indicator): this 1-bit flag shall indicate whether the link affects only one country (national) or several countries (international), as follows:
`0: national link;`
`1: international link (or DRM or AMSS).`
NOTE: If a linkage set includes services broadcast using DRM or AMSS, then the link will always be an international link, even if all linked services are intended for national use.
###LSN (Linkage Set Number): this 12-bit field represents a number which shall be common to all Services linked together as a set. The use of LSN = "0000 0000 0000" is reserved.
For an international link, the LSN shall be structured according to EN 62106 [5].
##Id list usage (P/D = "0"): ###Rfu: this 1-bit field shall be reserved for future use of the Id list qualifier, the Shorthand, the Number of Ids and the Id list fields. The Rfu bit shall be set to zero for the currently specified definition of the associated fields.
###IdLQ (Identifier List Qualifier): this 2-bit field shall indicate how the identifiers, contained in the Id list, are qualified, as follows:
b6 - b5
0 0 : each Id represents a DAB SId (see clause 6.3.1);
0 1 : each Id represents an RDS PI-code (see EN 62106 [5]);
1 0 : each Id represents an AM service or an FM service without RDS;
1 1 : each ECC + Id represents a DRM Service Identifier (see ES 201 980 [18]) or an AMSS Service Identifier (see TS 102 386 [19]).
The IdLQ shall not apply to the first entry in the Id list when OE = "0" and when the version number of the type 0 field is set to "0" (see the Id list definition below).
###Shd (Shorthand indicator): this 1-bit flag shall indicate whether each of those programme service identifiers, contained in the Id list and having bits b11 to b8 (see clause 6.3.1) in the range "4" to "F" (expressed as a hexadecimal value), represents a list of up to twelve services sharing the same Country Id and the same eight least significant bits of the Service reference (see clause 6.3.1), as follows:
`0: Ids in the Id list represent a single service;`
`1: Ids in the Id list, having bits b11 to b8 in the range "4" to "F", represent up to twelve services.`
##Id list usage (P/D = "1"): ###Rfu: this 4-bit field shall be reserved for future use of the Number of Ids and the Id list fields. The Rfu bits shall be set to zero for the currently specified definition of the associated fields.
###Number of Ids: this 4-bit field. expressed as an unsigned binary number, shall specify the number of identifiers in the Id list (maximum 12 when P/D = 0 and ILS = 0, maximum 8 when P/D = 0 and ILS = 1 and maximum 6 when P/D = 1).
##Id list (P/D = "0"): ###Id (Identifier of Service): this 16-bit field shall identify the programme service, depending on the Id list qualifier field and the shorthand flag. When the Id list qualifier = "11", the Id field shall carry the two least significant bytes of the DRM or AMSS Service Identifier.
###ECC (Extended Country Code): this 8-bit field, together with the Country Id part of the SId, shall identify the country to which the Service belongs (see clause 8.1.3). When the Id list qualifier = "11", the ECC shall carry the most significant byte of the DRM or AMSS Service Identifier.
##Id list (P/D = "1"): ###SId (Service Identifier): this 32-bit field shall identify the data service (see clause 6.3.1).
When the list of all the services, that are associated with the link, includes an SId, that applies to a service carried in the ensemble, the OE flag (see clause 5.2.2.1) shall be set to "0". In this case (OE = "0") and when the version number of the type 0 field is set to "0" (using the C/N flag, see clause 5.2.2.1), the first entry in the Id list of each Service linking field shall be the SId that applies to the service in the ensemble.
When the list of all the services, that are associated with the link, does not include a reference to a service carried in the ensemble, the OE flag shall be set to "1". In this case, there is no preferred order for the identifiers in the list.
The database key comprises the OE and P/D flags (see clause 5.2.2.1) and the S/H, ILS, and LSN fields.
The Change Event Indication (CEI) is signalled by the Id List flag = 0.