Content reference identifier: Difference between revisions

Revision as of 16:51, 10 November 2014

Latest revision as of 09:18, 25 February 2025

(14 intermediate revisions by 11 users not shown)

Line 1:

{{Use dmy dates|date=April 2014}}

{{cleanup-reorganize|date=April 2013}}

{{hatnote|1=CRID redirects here. CRID may also refer to a current rail indicator device, a safety device which indicatesindicating the presence of [[third rail]] power,[http://www.trainweb.org/tubeprune/dictionary.htm] or to a Cherenkov ring [[Ring-imaging Cherenkov detector.[http://www.osti.gov/bridge/purl.cover.jsp?purl=/57182|Cherenkov Ring-65UQ1E/57182.pdfImaging Detector]].}}

== Overview ==

A '''content reference identifier''' or '''CRID''' is a concept from the standardization work done by the [[TV-Anytime]] forum. It is or closely matches the concept of the [[Uniform Resource Locator]], or URL, as used on the [[World-Wide Web]]:

{{Quotation|A unit of content, in a [[Broadcasting|broadcast stream]], can be referred to by its globally unique CRID in the same way that a [[webpage]] can be referred to by its globally unique URL on the web.}}<!--source? or is it not a quotation?-->

The concept of CRID permits to referencereferencing contents unambiguously, regardless of their ___location, i.e., without knowing specific broadcast information (time, date and channel) or how to obtain them through a network, for instance, by means of a streaming service or by downloading a file from an Internet server.

The receiver must be capable of resolving these unambiguous references, i.e., translateof translating them into specific data that will allow it to obtain the ___location of that content in order to acquire it. This makes it possible for recording processes to take place without knowing that information, and even without knowing beforehand the duration of the content to be recorded: a complete series by a simple click, a program that has not been scheduled yet, a set of programs grouped by a specific criterion…

This framework allows for the separation between the reference to a given content (the CRID) and the necessary information to acquire it, which is called a “locator”. Each CRID may lead to one or more locators which will represent different copies of the same content. They may be identical copies broadcast in different channels or dates, or cost different prices. They may also be distinct copies with different technical parameters such as format or quality.

Line 16 ⟶ 15:

It may also be the case that the resolution process of a CRID provides another CRID as a result (for example, its reference in a different network, where it has an alternative identifier assigned by a different operator) or a set of CRIDs (for instance, if the original CRID represents a TV series, in which case the resolution process would result in the list of CRIDs representing each episode).

From the above it iscan obviousbe concluded that, provided that a given content can belong to many groups (each possibly defined by distinctive qualities), it is possible that many CRIDs carry the same content. That is, several CRIDs may be resolved into the same locator.

A CRID is not exactly a universal, unique and exclusive identifier for a given content. It is closely related to the authority that creates it, to the resolution service provider, and to the content provider in such a way that the same content may have different CRIDs depending on the field in which they are used (for example, a different one for each television operator that has the rights to broadcast the content).

Line 22 ⟶ 21:

== Format ==

A CRID is specified much like URLs. In fact, a CRID is a so-called [[uniform resource identifier|URI]]. Typically, the content creator, the broadcaster or a third party will use their [[___domain name system|DNS]]-names in a combination with a product-specific name to create globally unique CRIDs. That is, the syntax of a CRID is:

crid://authority/data

Line 27:

As an example, let's assume that [[BBC]] wanted to make a CRID for (all the programs of) the Olympics in China. It may have looked something like this

crid://bbc.co.uk/olympics/2008/

This would be a group CRID, that is, a CRID representing a group of contents. Then, to refer to a specific event – such as the women's shot-put final – they could have used the following inside their metadata.

crid://bbc.co.uk/olympics/2008/final/shotput/women

Line 37 ⟶ 39:

The locators' format, as established in TV-Anytime, is quite generic and simple, and corresponds to:

&lt;[transport-mechanism&gt;]:&lt;[specific-data&gt;]

The first part of the locator’s format (the transport mechanism) must be a string of characters that is unique for each mechanism (transport stream, local file, HTTP Internet access…). The second part must be unambiguous only within the scope of a given transport mechanism and will be standardized by the organism in charge of the regulation of the mechanism itself.

For instance, a DVB locator to identify a content within the transport stream of networks that follow this standard would be:

dvb://112.4a2.5ec;2d22~20121212T220000Z—PT01H30M

Line 92 ⟶ 96:

In May 2005, an Informational RFC, [http://tools.ietf.org/html/rfc4078 No 4078], was published as the start of this work.

The long-term goal is that CRIDs should be available for use by [[cell phones]], [[Personal digital assistant|PDA]]s, [[Digital television|digital TV]] [[Set-top box|receivers]] and other [[Consumer electronics|consumer devices]] for fetching content, either from a broadcast stream or over [[internet protocol|IP]]-based [[computer network|networks]]s.

== See also ==

Line 99 ⟶ 103:

== References ==

* [ftphttp://ftp.rfc-editor.org/in-notes/pdfrfc/rfc4078.txt.pdf RFC 4078 (PDF)] Accessed 27 October 2011

* [ftphttp://ftp.rfc-editor.org/in-notes/rfc4078.txt RFC 4078 (TXT)] Accessed 27 October 2011

* [http://www.etsi.org/deliver/etsi_ts/102800_102899/10282202/01.04.01_60/ts_10282202v010401p.pdf ETSI TS 102 822-2 V1.4.1 (2007–11), Page 19, Section 5: "TV-Anytime content referencing scenarios"] Accessed 3 December 2012

* [http://www.etsi.org/deliver/etsi_ts/102800_102899/10282204/01.07.01_60/ts_10282204v010701p.pdf ETSI TS 102 822-4 V1.7.1 (2012–12), Page 13, Section 8: "CRID"] Accessed 9 January 2013