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@@ -0,0 +1,33 @@ +TV-Anytime is the name given to a set of technologies which aim to simplify the +process of recording and replaying broadcast content. The standards are published +by ETSI and are available without cost from www.etsi.org (registration required). + +In the UK a subset of the TV-Anytime specification is broadcast on the DTV service +under the trade name "FreeView Plus". This patch is written for the UK version but +should work with the full specification. + +TV-Anytime data is contained in Content Reference Identifiers (CRIDs). The syntax +of a CRID is described in RFC 4078; it is a URI-compliant string of the form: + + crid://<DNS name>/<data> + +in which <DNS name> is a registered internet domain name (RFC 1034) and <data> is +a free-format string. The <DNS Name> section relates to the content provider (TV +channel or company), and the <data> section to the programme. + +CRIDs are transmitted in the EIT as Content Identifier Descriptors, with descriptor +ID 0x76. To save bandwith only the <data> section is sent, the <DNS Name> part is +taken from the Default Authority Descriptor in the SDT, and the crid:// is assumed. + +A programme may have up to two CRIDs in its EPG entry. One identifies the specific +item of content which is being broadcast, while the other identifies a series of +programmes which this item belongs to. In FreeView Plus these CRIDs have crid_type +values 0x31 and 0x32 respectively (TV-Anytime uses values 0x01 and 0x02). + +To give an example, the programme "Torchwood" broadcast on channel BBC2 at 21:00 on +2008-01-16 had item CRID '54BXLC' and series CRID 'KCJ00C'. When the same programme +was repeated the following day on channel BBC3, the item CRID remained the same but +the series CRID was 'KCJ12C'. Meanwhile the episode broadcast on BBC2 one week +later on 2008-01-24 had CRID '54BXLD' but the same series as the previous week. Hence it is possible for a PVR to record an entire series by using the series CRID, or to find an alternative broadcast for an individual item if there is a clash with +another recording. + |