RSS-TV is an extensible markup language (XML)-based navigation protocol for Internet Media services based on the RSS standard. The adoption of RSS-TV enables video device manufacturers to develop applications to seamlessly navigate premium Internet video services. Example video devices include set top boxes, portable video players, game consoles, broadband-connected digital video disc (DVD) players, digital video recorders (DVRs), portable video players and mobile phones. By implementing the RSS-TV protocol, these devices provide user access to a growing library of online media (video, audio, games) services.

RSS-TV is an extension of RSS and includes additional XML elements and attributes to enable broadband media service features such as:

• Video On Demand (VOD) and Subscription Video On Demand (SVOD)
• Navigating media services (video, audio, games) in a hierarchical fashion
• Capturing user input (such as a user personal identification number (PIN), search query, or email) and automatic search suggestions.
• Network PVR functionality
• Secure download of HD content
• Electronic Program Guide for live streams
• Automatic language selection
• Numeric shortcuts for selecting menu items

Readers familiar with digital video broadcasting (DVB) can compare RSS-TV with the DVB Service Information standards developed in the 1990s for digital TV EPGs. The difference is that RSS-TV has been developed for two-way Internet Protocol (IP) networks rather than broadcasting networks. RSS-TV leverages the increasing availability of products that support RSS such as caching engines and RSS-enabled content management and publishing systems.

RSS-TV-compliant applications can be implemented using any language and operating system including AJAX/HTML, Flash, OpenTV, or C.  Similarly, service providers can use any web service technologies (Java, .NET, PHP) to build RSS-TV-compliant services.

Podcasting

RSS-compliant feeds that use enclosures for video/audio (podcasting) are fully compliant with RSS-TV. RSS-TV-compliant clients will display these feeds as a list of menu items and will play or download the media.

RSS-TV Namespace

RSS-TV uses the namespace 'tv'. For example, the RSS-TV XML element duration is identified by <tv:duration>. The official schema will be made available at http://www.rss-tv.org/rss/tv1.0.

Encoding

Similar to other XML-based standards, RSS-TV documents are assumed to be 8-Bit Unicode Transformation Format (UTF-8) encoded.

References to standards

Revision history

RSS-TV 2.0

RSS-TV 2.0 was established after field tests and numerous protocol reviews.  RSS-TV 2.0 is ready for commercial rollout of Internet video services to TV and other video capable devices.  Any future specifications will be fully backwards compatible with RSS-TV 2.0.

Changes

Summary of changes introduced with RSS-TV 2.0:

• Introduction of <tv:meta>.  <tv:category> <tv:copyright> <tv:countries> <tv: keywords> and <tv:rating> removed in favor of generic <tv:meta> with pre-defined meta types such as category, copyright, etc.
• Support for basic markup in <description>.  <tv:itemheader> removed in favor of enabling basic markup for descriptions.

The following XML document is an example of a 'root' menu representing the top level of a hierarchical menu structure:

<?xml version="1.0"?>

<rss version="2.0" xmlns:tv="http://www.rss-tv.org/rss/tv1.0">

   <channel>

      <language>en-us</language>

      <title>Main Menu</title>

      <tv:help>http://www.test.com/menu/?id=help</tv:help>

      <item>

         <title>TV On Demand</title>

         <description>Watch TV from thousands of programs.</description>

         <link tv:type="rss">http://www.test.com/menu/?id=tvod</link>

      </item>

      <item>

         <title>Live TV</title>

         <description>Tune in to hundreds of live channels</description>

         <link tv:type="rss">http://www.test.com/menu/id=livetv</link>

      </item>

      <item>

         <title>Movie Store</title>

         <description>Starting at 1 Euro for 24 hours</description>

         <link tv:type="rss">http://www.test.com/vod/</link>

      </item>

      <item>

         <title>Local Weather</title>

         <description>Check out our 7 day weather forecast</description>

         <link>http://www.weather.com/iptv/</link>

      </item>

      <item>

         <title>Settings</title>

         <description>Change your PIN and network settings</description>

         <link tv:type="rss">http://www.test.com/menu/?id=setting</link>

      </item>

      <item>

         <title>Introduction video</title>

         <description>How to use this video service</description>

         <enclosure url="rtsp://www.test.com/v/intro.mp4" type="video/mpeg"/>

      </item>

   </channel>

</rss>

Most items in this sample RSS-TV document link to other RSS-TV documents, creating a hierarchical menu structure. The document also contains a node item linked to an HTML weather application.  Depending on the capabilities of the box, this item may be hidden from the user.

The document also includes an example node that links directly to a MPEG-4 video streaming media file using the RSS enclosure element.  All link types and RSS-TV extensions are described and specified in this document.

A typical RSS-TV-compliant Internet video device will boot up, connect to the network, check for firmware upgrades, load the navigation client application, authenticate (optional), and load a predefined RSS-TV URI that contains the top level of the menu structure.

One of the important features of RSS-TV is its support for a hierarchical menu structure. This structure is achieved by linking one RSS XML document (parent) to other RSS XML documents (children) using <link tv:type="rss">.

The endpoints or 'leaves' of the hierarchical menu link to video, audio, Flash applications (through RSS enclosures), HTML applications, or special RSS-TV menu actions. The available item types are documented in the RSS-TV <item> Extensions section.

The following diagram shows a small sample hierarchical menu:

In one example implementation, the user can navigate the services by simply using the up, down, left, and right navigation keys.

The user navigates <up> and <down> to make selections, and <right>/<ok> to activate selected items. Navigating <left>/<cancel> cancels the current menu and returns the user to the previous menu.

During navigation, the user's thumb remains around the arrow control, except when entering alphanumeric information such as a user PIN or a movie search query.

RSS-TV does not impose any specific user interface or design.  The look and feel of the navigation client application can be completely customized and optimized for the client device platform, independently of the services. It is therefore possible to present the same RSS-TV items using a completely different navigation client application.  RSS-TV does allow service directives to instruct the navigation client application to apply certain widgets (text, image, mosaic) and styles.

Menu Levels

An RSS-TV-compliant client device maintains the notion of menu levels. Each menu is served on a particular level in the menu hierarchy, starting with level 0 at the root. This enables an RSS-TV application to jump to a previous menu level or to jump n steps backward in the hierarchy.

RSS-TV services that contain circular menu structures (one where a user enters an incorrect email address and password, for example) should ensure that menus are traversed correctly so that the 'back' function operates as expected.

For example, a user who attempts to enter a PIN code should be directed to the PIN entry menu through relative addressing (menu:-2) rather than hard-coded URIs.  More information can be found in the section RSS-TV <item> Extensions.

HTTP POST

The menu history may contain POST links resulting from an input item. The client shall automatically re-POST content entered by the user if a previous menu level is called.

Bypassing Menu History

By default, the client stores each menu TV URI in a menu history.  This enables the device to go back in history when the user presses a 'back' button or 'left' button on the remote control.

An RSS-TV link in a single-item response (see Single Item Response) is not stored as a separate entity in the menu history.  The client menu history only stores the original RSS-TV link that returned the single item response.

An input item may indicate that the associated RSS-TV URI should not be stored in the menu history. See the section on 'Capturing User Input' for more details.  This can be used for functionality such as capturing a PIN code, in which case the user should not return to the PIN entry screen when going 'back' from a subsequent menu page.  Example sequence:

Displaying Currently Playing and Downloading Media

When the client navigates through the menu structure, the menu item list may contain a media item that is currently playing or downloading.  In that case it is useful to show the user a specific icon (like a speaker icon for playing audio) or the state of the download process.  This is referred to as ‘active media’.

In order for the client to identify active media, the RSS-TV service must include the RSS <guid> element in the media <item> elements.  The client can use the RSS <guid> to match the currently active media with the media item in any media item list.

The <enclosure> URL can not be used to uniquely identify a media item because:

• The enclosure URL is not guaranteed to be a unique identifier of the underlying media item (different URLs may point to the same media)
• An RSS item may not contain an enclosure, but rather an RSS-TV link that will return a single item with an enclosure.

A menu may contain a number of media items with audio or video enclosures.  An RSS-TV compliant client may or may not automatically start the subsequent item in a list after an item has finished playing.  It is recommended that the client enables ‘zapping’ functionality using ‘next’ and ‘prev’ to allow the consumer to zap through the media items.  See the specification of <tv:zap> for more information.

Server Side Play Lists

Server Side Play Lists can be used for dynamically inserting advertising or dynamically creating play lists for online radio channels.  The RSS-TV service provides a URL which is called to return the ‘next’ item in the play-list.  This URL will be called by the client at the end of the current item using the <tv:done> extension of the <item> element.  See the specification of <tv:done> for more information.  See the specification of <item tv:noskip> for more information about implementing advertising models.

An example URL and HTTP response of such a play list web service:

http://www.last.tv/playlist/

<?xml version="1.0"?>

<item xmlns:tv="http://www.rss-tv.org/rss/tv1.0">

   <title>Umbrella</title>

   <tv:meta type="artist" display="Artist">Rihanna</tv:meta>

   <guid>8435987546</guid>

   <enclosure url="rtsp://www.cdn.com/v/?id=8435987546"/ >

   <tv:done>http://www.last.tv/playlist/</tv:done>

</item>

The web service may use session and cookie information to determine the next media item in the list and construct a personalized play list.

A TV service can be made more compelling if basic user and device information can be accessed by services automatically. This enables various features such as:

• Automatically selecting the appropriate user preferred language
• Consistently classifying the regional location (country and city) of the user across services.
• Sharing basic user information such as name and age across services
• Only listing media services that are supported by the device

User Information

RSS-TV defines an HTTP cookie-based mechanism to set and access user information. Implementation of user information is not mandatory for RSS-TV compliance. The RSS-TV specification only makes it easier to exchange this information if it exists.

Service providers should ensure that information shared with third-party services is in line with privacy policies accepted by the user.

Cookies

All information is exchanged through the use of standard HTTP cookies. Cookies are typically set on the domain level (e.g. iptv.net) to ensure that multiple RSS-TV media services can access the cookies (e.g. music.iptv.net, movies.iptv.net, or sports.iptv.net).

User Information

User data is exchanged using a multi-value cookie named 'User'. The following parameters are defined:

Example:

User=Name=Robert&Language=en&IPCountry=us&IPState=ca&IPCity=San Diego

Local Services

A DNS entry of localhost.<domain> (e.g. localhost.iptv.net) on the client device can be mapped to localhost (127.0.0.1) to ensure that cookie values are also passed to the local web services. Similar techniques can be used to provide other local home network servers access to the cookies (homepc.iptv.net).

Security and Trust

Cookie values can be modified by the user and cookies can also be modified by any of the other web services that operate in the same domain. Therefore, web services should not rely on cookies for tasks that require authenticity.

Device Information

Client devices will differ in capabilities based on installed hardware and software. Presenting services to users that can not be accessed with the device can be frustrating and should be prevented.

User-Agent

RSS-TV navigation servers assume that the client device makes use of the standard HTTP header 'User-Agent' to include device information that can be linked with device capabilities.  The minimum information about the device included in the User-Agent HTTP header is:

• Make (manufacturer)
• Model
• Firmware
• Resolution

Example:

      Mozilla/4.0 (compatible; Sony; PS3;V3.289.2; 720x576)

Storage

An RSS-TV client device can signal storage capabilities by setting the HTTP private header 'Rsstv-Storage' to 'true' or 'false'.  By default, the device is assumed to have storage capabilities.

Network Information

An RSS-TV client device can signal bandwidth availability by setting the HTTP private header ‘Rsstv-Bandwidth’ to the maximum sustainable bandwidth available to the device in kbit/s.  The RSS-TV service may use this information to automatically select the appropriate video stream if multiple bitrates are available.

How available bandwidth is measured is outside the scope of RSS-TV.

Caching

An RSS-TV service may enable a client to cache RSS-TV documents for performance reasons.  The RSS-TV service shall use the HTTP header ‘Cache-Control’ using the directive ‘max-age’ to inform the client how long it may hold a copy of the document in its cache.

The following HTTP header enables a client to cache the corresponding document for 10 minutes:

Cache-Control: max-age=600

Instead of returning an RSS document with multiple items, a service may return a single item that needs to be immediately executed by the client device.  This feature is used to redirect the client to another RSS-TV service or media. For example:

• A user purchases a movie and submits a PIN using an input response. The web service checks the PIN code and then redirects the user to the video.
• The user changes the language of the TV menu. The web service updates the user profile and redirects the user to one level higher on the menu
  (-1).

A single-item response contains a single XML item element. The following example provides a sample response:

<?xml version="1.0"?>

<item xmlns:tv="http://www.rss-tv.org/rss/tv1.0">

   <link tv:type="action">menu:0</link>

</item>

In this response, the client returns to the top-level root or 'home' menu. The response may also contain a link of another type (rss or action) or enclosures (audio, video, or flash), and the item may include any regular item XML elements such as title and <tv:meta>.

The single item response may also include an enclosure with metadata as shown by the following example:

<?xml version="1.0"?>

<item xmlns:tv="http://www.rss-tv.org/rss/tv1.0">

   <title>The Matrix</title>

   <description>A computer hacker learns from mysterious rebels about the true nature of his reality and his role in the war against the black force</description>

   <tv:meta type="rating" display="Rating">PG-13</tv:meta>

   <tv:meta type="genre" display="Genre">Action</tv:meta>

   <enclosure url="rtsp://www.cdn.com/v/?id=23"/ >

</item>

Menu history

A single-item response should not be added to the menu history of the client device. Pressing 'back' on a menu that resulted from a single-item response shall return the client device to the most recently processed RSS menu or user input request.  Read section 'Menu Structure' for more information about maintaining menu history information.

The RSS-TV protocol allows a service provider to capture user input such as a PIN code, an email address, or a search string to find a movie. This is achieved using the 'input' XML document.

The RSS protocol only allows a single input field per RSS document. This ensures a user-friendly, wizard-like experience. Capturing multiple fields such as email and password must be implemented using two separate RSS-TV documents (thus using two consecutive screens). This is an intended limitation.

The RSS-TV input response includes elements that enable features such as strict input text types (password, email, text, pin, or telephone), automated suggestions, and input language selection.

The following example shows a sample response to capture a search string:

<?xml version="1.0"?>

<input xmlns:tv="http://www.rss-tv.org/rss/tv1.0">

   <name>search</name>

   <action>http://www.iptv.net/search.jsp</action>

   <type>alphanumeric</type>

   <maxlength>10</maxlength>

   <suggest>http://www.iptv.net/suggest.jsp</suggest>

   <title>Search</title>

   <description>Type the name of the movie or actor</description>

   <style>premium</style>

   <image>

      <url>images/boxart.jpg</url>

      <height>180</height>

   </image>

</input>

When the user confirms the input, the client device shall POST the value of the input field to the action URI using regular FORM POST syntax (the value must be URL encoded). The following example assumes the name of the input field is 'search' and the user entered 'james' to complete the search query:

search=james

The following sections specify the input XML elements:

Action

The element 'action' contains the URI where the final result shall be posted.

Description

The element 'description' contains a long string to describe the input field. This information helps the user understand what input is required. Example values are 'Enter the first characters of a movie name or the name of an actor to find a movie'.  The description may contain basic markup as specified in the section RSS-TV <description> Extensions.

Image

The input can be associated with an image to remind the user why the input is required.  For example a thumbnail of a movie to confirm a purchase, or an image of a lock for entry of a PIN code.

Language

The 'language' element is used to determine the appropriate character set for entering user input.

Maximum Length

The 'maxlength' element contains the maximum length of the field. The default value is device dependent.

Menu History

The 'menuhistory' element can be set to 'false' to prevent the client device from adding the input item in the menu history. See also Menu History.

Name

The element 'name' contains the form field name of the value that shall be posted to the action URI.

Style

The service can request the navigation client application to change the style (background, colors, etc.) of the input menu page.

Read the RSS-TV Channel Extensions section for more information about styles.

Suggest

The 'suggest' element is used to retrieve suggestions based upon currently entered characters.

The 'suggest' URI can be used by the client device to display a list of suggestions based on the input characters entered so far. See also 'Google Suggest' (http://www.google.com/webhp?hl=en&complete=1) for an example implementation of such functionality. The client device shall POST the contents of the input element to the 'suggest' URI when a new character is entered by the user, using the same HTTP POST syntax as submitting the final result to the 'action' URI. The server responds with an RSS-TV compliant XML document with the suggested items included in the response.  The user can select one of the suggestions to activate the associated RSS-TV item.

Client device implementation of the suggest URI is optional and is not required for RSS-TV compliance.

Title

The element 'title' contains a short string to describe the input field. Example values are 'Find a Movie' or 'Enter your PIN'.

Type

The element 'type' is used to indicate what type of input field is expected. This can be used by the client device to simplify the user interface. For example, entering a field of type 'email' could make the characters '.' and '@' more prominent and leave out the option of capitols, spaces and special characters that are not allowed as part of an email address.

Accepted values for <type> are:

Value

The 'value' element allows the service provide to pre-fill the value of the input field to minimize user input efforts. For example, a URL input request could set <value> to 'http://www.'.

This section lists the RSS-TV extensions of the RSS <channel> element that shall be supported by a RSS-TV-compliant client device.

This section describes the following extensions in alphabetical order:

Autostart

The service may request the client to immediately start the selected media item.  The user only needs to enter the corresponding number (see <tv:number>), or the service may have pre-selected a media item (see <tv:selected>).  The user does not require to activate (press the RCU ‘OK’ button) the selected menu item.

The default value is ‘false’.

Example

<?xml version="1.0"?>

<rss version="2.0" xmlns:tv=" http://www.rss-tv.org/rss/tv1.0">

   <channel>

      <title>Live TV</title