Meet the Green Button! New Developments on Freeview+ and Freeview+HD: Trailer Booking
A feature that all new Freeview+HD recorders are required to support is "Trailer Booking", also known as Green Button. This new feature allows broadcasters to send metadata about a trailer in-time with on-screen trailers. The metadata tells the recorder what is being trailed so the viewer can book a programme to be recorded when the green 'Book Me' icon pops-up. No need to go searching through the EPG for it.
The BBC has been broadcasting this service on BBC1,2,3,4 and the HD channel since the end of May, although on BBC1 and 2 is only available in England at the moment. We are currently assessing the challenges of rolling it out on BBC 1 and 2 in Northern Ireland, Scotland and Wales.
The mechanism builds on the existing features of Freeview+ recorders that the BBC already supports such as series linking, repeat identification and recommendations.
The whole system is reliant on an identifier called the Content Reference ID (CRID). This allows the identification of a programme rather than a timeslot in the schedule. It also allows the abstract identification of a series. This concept has been around for some years and comes from a set of specifications defined by the TV-Anytime Forum but the BBC was the first to broadcast these ids over-air with the launch of Freeview Playback (now Freeview+). This separation of programme from schedule means we can promote a programme or series long before it appears in the schedule - so the viewer can book programmes and series based on those 'coming soon' trailers.
R&D have been fundamental to this complex project, which involved different BBC departments ("Marketing, Communications & Audiences (MC&A)", Future Media & Technology, and Distribution) and our technology and metadata suppliers - we had to make the business processes work to support this and to get the right systems in place to produce the correct information at the right time. We've worked with recorder manufacturers, through the Digital TV Group (DTG), as they add this feature into their new products.
Behind the launch of this feature by the BBC are many years of investigation by R&D. We initially contributed to the DVB standard (Carriage of TV-Anytime over DVB networks, ETSI 102 323) which determines the interchange between the broadcaster and receiver. Through the DTG D-Book process we profiled how the DVB tool kit would be used in the UK and defined how the recorder could and should use the information signalled by the broadcaster. This aspect required significant discussion with receiver manufacturers because although the TV-Anytime standard (TS 102 822-3-1) specifies different types of linkages (in the 'HowRelated' classification scheme) how the types should be used, e.g. what a receiver should do with a link type called 'IsTrailerOf', needed to be defined locally (i.e. in the UK). Throughout all this we had built an end-to-end test and development chain in our lab, and even built some prototype/test receivers to make sure we had the signalling right.
Within the BBC itself we helped MC&A integrate the correct processes to support the new signalling. We had worked with MC&A before to enable trailer booking on the Sky platform. This mainly meant enabling the correct linkages in the information sent to Sky by our metadata distributor. For Freeview we needed to source extra identifiers and metadata from within the BBC and our metadata provider in order to provide such things as the promotional text with each link, and help commission a brand new system to generate this signalling.
There were other interesting technical challenges in this project: Trailer booking relies on the in-built 'native' software of the recorder to book programmes to be recorded rather than any kind of MHEG application - trailer booking does not use MHEG. One of the reasons for this approach is that each recorder has it own way of presenting a booking to the viewer, and so trailer booking needed to be a familiar user experience. However, it is quite unusual for a broadcaster initiated action to cause something to pop-up on the native user interface - most of the time it is viewer initiated, e.g. changing channel, pressing the info button, selecting the guide (obviously broadcaster initiated pop-ups happen all the time in the MHEG application domain). Many MHEG applications run in a 'sandbox', in that the recorder can't easily tell in how the user is interacting with the MHEG application, e.g. whether the application is in full-screen mode or just an icon is showing. Also, some receiver software cannot display native graphics and MHEG graphics simultaneously. The problem this gives is that it would be an annoying user experience if the recorder put up a green 'book me' icon over an MHEG application or, even worse, tore down the MHEG application, while it is being used by a viewer, in order to put up a green icon. To solve this problem R&D and the recorder manufacturers came up with a way for MHEG and trailer booking to co-exist, whereby the MHEG application has the ultimate control of when green button icons are permitted. So, when the user starts to use MHEG, the MHEG application can choose to suppress trailer booking pop-ups. When we were reviewing this idea we built this into our prototype receiver to check this feature would behave as expected.
Being able to deliver synchronised typed metadata, which is what trailer booking is an example of, is just the start. The specifications, DTG tests and head-end are designed to allow future expandability. Now this data stream and supporting processes are in place there's much more we can add. For example, there's whole range of different link types available. So watch this space.
Look out for trailer booking on the new range of Freeview+HD PVRs - it's a standard feature.