Data and object carousel

In <a href="/facts/Digital_Video_Broadcasting/KPGNTGBJ">digital video broadcasting</a> (DVB), a data and object carousel is used for repeatedly delivering data in a continuous cycle. Carousels allow data to be pushed from a broadcaster to multiple <a href="/facts/Receiver_(radio)/5olDTxkg">receivers</a> by transmitting a data set repeatedly in a standard format. A set-top box receiver may tune to the data stream at any time and is able to reconstitute the data into a <a href="/facts/Virtual_file_system/lRI31T4T">virtual file system</a>. The carousel may therefore be considered as a transport file system or file broadcasting system that allows data files to be transmitted from the broadcaster to multiple receivers or clients simultaneously.
In a unidirectional broadcast environment, the receiver is unable to request the retransmission of any data that was missed or received incorrectly. Repeated retransmission of data allows the receiver to cope with random tuning to a channel at an unpredictable time, for instance as the user changes a channel.
The carousel cycle period generally determines the maximum time required for a receiver to acquire an application or specific datum. It is possible to reduce the access time for commonly used files by broadcasting some data more often than others.
An individual object carousel is also called a service domain in some documents. To be precise, a service domain is a group of related DSM-CC objects. In broadcast systems, there is no difference between an object carousel and a service domain except for the terminology: an object carousel is a service domain, and vice versa.

Data and object carousel open-in-new

Data and object carousel