There are a large number of standards to consider when representing radio data.
One thing we want to avoid is creating any more standards.
To summarise, we have chosen Atom as our basis for metadata. See that page for the reasoning.
Here we discuss other standards and how we use them. This is not intended to be a complete list and other sections may be added.
RSS is a well known format used for feeds in many contexts. Notably it is used for podcasting by using audio enclosures.
For end-users it is the most popular feed format, with much wider usage than Atom.
So why not use RSS for radio metadata?
The main reason is that there is no definitive standard for RSS. RSS is essentially a number of loose standards and a lot of common practice.
The standard linked above is an advisory document based on the way RSS is used.
So there are some questions it is hard to answer definitively about RSS. For example, can an RSS item contain more than one enclosure element? Opinions vary on this. See e.g. http://www.reallysimplesyndication.com/2004/12/21 and http://www.therssweblog.com/?guid=20070520140855 . Note that the Atom Links mechanism solves all these problems.
There is no XML namespace or registered MIME type for RSS.
So for interoperability in a B2B context, RSS is not suitable, as different interpretations of RSS usage will lead to incompatibilities.
For presentation to end users, RSS is ideal however. As Atom and RSS are equivalent, Atom can be converted to RSS for end-user consumption.
A comparison of Atom and RSS can be found at [Wikipedia]
The Radioplayer UK project is an internet service formed by the BBC, Global Radio and the Guardian Media Group. It supplies a live feed of radio stations across the world using a standard screen interface. The feed is delivered using Digital Audio Broadcasting (DAB); a digital radio technology used for broadcasting radio stations.
The focus of Radioplayer is on a consistent end-user experience rather than on metadata and interoperability.
However, Radioplayer does define a standard metadata format. The documentation for this is not publicly available.
It is based on the DAB EPG XML spec (ETSI TS 102 818), available here: http://www.etsi.org/deliver/etsi_ts/102800_102899/102818/01.04.01_60/ts_102818v010401p.pdf
This is a complex specification aimed at terrestrial and satellite broadcasters, designed for use on Digital Audio Broadcasting devices. For larger members of Radioplayer who already had an implementation of this spec, this may have been an advantage, but it may have proved a barrier to entry for smaller stations and has been followed by recent move at Radioplayer to ingest RSS2 feeds.
Late in the development process, various incompatibilities were found with the original DAB spec requiring some changes and a new namespace. So the current spec is not an application of the DAB spec, it is a new and similar markup.
The Radioplayer spec is focused on live streaming radio, with ondemand as an addition. It requires users to have a unique ID that is allocated by Radioplayer, so this format is not really usable outside the Radioplayer ecosystem.
However, it is possible to generate Radioplayer EPG data from an Atom feed and Radioplayer now accept RSS feeds which are simple to generate from Atom.