This is Project Baird.

Determining whether a programme is or will be available for on-demand viewing

  1. Construct a TVDNS or RadioDNS domain name for the current service

  2. Query DNS for the content-manifest application

  3. Download the manifest XRD document and locate the feed related to the current service

  4. Download the feed for the current service

  5. Locate the atom:entry related to the current programme, using atom:link elements specifying rel="alternate" with an href attribute containing the current programme’s crid:// URI or some platform-specific URI (e.g., a dvb:// URL).

  6. Examine the atom:link elements within the entry for those which specify rel="alternate" (or equivalent, depending upon Atom’s parsing rules)

  7. Filter those atom:link elements matching the above by their type (based upon those content types supported by the device), le:media (if present) and baird:dtend attributes, removing any which have type values indicating unsupported content or baird:dtend values indicating that the availability window has already passed.

  8. If any atom:link elements remain:

    • If there are any whose baird:dtstart attribute is in the past or absent, the on-demand window is currently in progress
    • If there are any whose baird:dtstart attribute is in the future, the on-demand window is in the future
  9. Indicate on-demand availability to the user


  1. Broadcaster prerequisites:
    • TVDNS domains for the services it broadcasts are configured and registered with the TVDNS administrative body or hierarchical parent (e.g., platform operator), as appropriate
    • SRV and TXT records for the feed manifest have been published
    • Properly-populated feed manifest and service feeds are available
  2. See for a description of element, attribute and link relation extensions
  3. See the device profiles for information on anticipated content type support on different devices
  4. See Atom Link Extensions for information on the le:media attribute.
  5. Media queries are defined by the Atom Link Extensions specification to match those specified by CSS3