Promise.tv technology
Freeview digital TV is transmitted using a number of digital multiplexes on an RF carrier. A multiplex is similar to an analogue TV channel, but contains about six digital channels using compression techniques along with associated metadata.
Promise.tv decodes the transmitted carriers and stores the multiplexes in digital form on a hard disk drive. Using a suitably large amount of storage, all of the multiplexes can be stored as they are transmitted over a seven day period.
The video data is stored in a circular format such that the newest programmes automatically overwrite the oldest programmes, and a continuous seven days programming is available at any time.
Simultaneously, the stored multiplexes may be retrieved for decoding and display on a television, enabling any channel recorded on any day to be viewed at any time.
Programmes can be saved for longer than the seven day period. By tagging them after they have been stored, they can be transferred to a separate storage area for archiving. Programmes can also be transferred to external storage such as DVD.
The system can be expanded by adding more storage to permit, for example, one entire months broadcast transmissions to be stored.
As presently configured, up to four separate remote decoder boxes (thin clients) can be added away from the main promise.tv storage unit. This would allow four different (or even the same!) recorded programmes to be viewed simultaneously on separate televisions.
Programmes can be found through different indexing methods, including a simple time and day listing, alpha-numeric search, favourites and a category based (genre) filter. This divides programmes into ten categories including for example sport, entertainment, childrens and music. This information is extracted from the metadata which is transmitted alongside the programmed by the broadcaster.
Promise.tv is NOT just a giant PVR. Promise.tv is, in effect, an entirely impersonal PVR. It is non-discriminating allowing any viewer to watch any programme at any time over the stored seven day period.
The television stream is stored without any segmentation. This means that the user can start at any stored programme and seek backwards into the previous programme, forwards into the next or even sideways across different channels.
Replaying programmes recorded on promise.tv represents true time-shifting. Changing channels during replay shows all the different programmes that were being broadcast at the displayed time on that day. Replaying programmes in this way is in effect rewinding the entire broadcast stream instead of just individual programmes.
All information is sourced from the broadcast signal. No internet or phone line connection is required.