Oy Nokia Ab

Ari Salom&auml;ki

The invention relates to the transmission of files in a digital broadcasting system, particularly in a DAB system according to the standard ETS 300 401. According to the invention, a file descriptor ( ) is created for each file. This file descriptor is of the data group type denoted by 0011 in said standard and includes parameters ( ) describing the file associated with the descriptor. The file descriptor is transmitted in the broadcasting system before the file and possibly also during the transmission of the file. The information to be transmitted is divided into segments, which are identified in a file-specifically unique manner, such as consecutive numbering, which starts from zero at the beginning of each file.

Transmission protocol for file transfer in a DAB system

To prevent unauthorized reception, storage, copying and reproduction of digital media objects it is defined in addition to a scrambled broadcast format a scrambled storage format which is different from the broadcast format. A user's terminal equipment cannot receive, store or reproduce protected objects without a key which is advantageously a bit sequence stored on a portable memory medium and which can be different according to the type of use it gives entitlement to. To prevent the storing and later reproduction as such of data in the broadcast format, a time stamp is included in the broadcast format representing the time of broadcasting. A playback device cannot reproduce a broadcast-format object if the reproduction time differs from the time stamp included in the broadcast format. The reproduction time is advantageously read from a real time clock of a portable memory medium.

Growing community of inventors

Järvenp{umlaut over (aa)}, Finland

Ari Salomäki

Growing community of inventors

Järvenp{umlaut over (aa)}, Finland

Ari Salom&auml;ki

Ari Salomäki