U.S. Philips Corporation

Koninklijke Philips Corporation N.v.

Jurgen F Rosengren

Ronald W Saeijs

Rudolf H Bloks

Thomas A Suters

Eric H Persoon

Guy J Roberts

Joanne H Westerink

Michiel J Van Der Korst

Method and device for transmitting data packets from an input stream of data packets into an output stream of packets. When a plurality of transport streams is multiplexed, packet jitter may be introduced to such an extent that decoder buffers can overflow or underflow. This is avoided by associating a time window with a data packet and accommodating position information in the packet about the position of the data packet within the window.

Method and device for transmitting data packets

Method and device for transmitting data packets (P,,P,,P,) from an input stream (TS,) of data packets into an output stream (TS) of packets. When a plurality of transport streams (TS,,TS,) is multiplexed, packet jitter may be introduced to such an extent that decoder buffers can overflow or underflow. This is avoided by associating a time window (LTW) with a data packet and accommodating position information (,) in the packet about the position of said data packet within said window.

A data bus system comprises a number of stations which are interconnected via a bus. The bus has a limited data transmission capacity available. From a transmitter station a resource control station reads which part of the available transmission capacity is required for the relevant transmitter. The resource control station allocates the required transmission capacity to the relevant transmitter station if adequate transmission capacity is available; it is only in that case that transmission by the relevant transmitter station is enabled.

Data bus system with resource control compensating for limited

A device for deriving an ancillary signal from a compressed digital video signal (e.g. MPEG), wherein the ancillary signal includes selected parts of the main signal, for example, the DC coefficients of I-pictures, or the unscrambled parts, which parts can be used for display in a (multi-) picture-in-picture television receiver, or as an 'appetizer' in order to encourage the user to pay a subscription fee, is described. The ancillary signal can separately be recorded in digital video recorders so as to assist the user in finding the beginning of a scrambled program on tape. The ancillary signal can also be generated at the transmitter end and transmitted at a low bit rate. A decoder for decoding such an ancillary signal is considerably simpler and less expensive than a full-spec MPEG decoder. A decoding method is also described.

Method and apparatus for multiplexing and transmitting

A transmission network having a plurality of transmitter stations receiving signals over different transmission links from a common source. The transmitter stations transmit frames including the same data packets, substantially simultaneously over the same frequency. To ensure that the same data packets are included in each given frame, the source adds frame start codes to the signals transmitted over the links.

Single frequency transmission network

A data bus system has a number of stations which are interconnected via a bus. The bus has a limited data transmission capacity available. From a transmitter station a resource control station reads which part of the available transmission capacity is required for the relevant transmitter. The resource control station allocates the required transmission capacity to the relevant transmitter station if adequate transmission capacity is available. Only if adequate transmission capacity is available is transmission by the relevant transmitter station enabled.

MPEG2-based transmission systems transmit a large number of digital television programs in a single physical channel. Disclosed herein is a 'Channel Navigation System' which allows a user to get an overview of the digital programs provided, and to easily select a desired program. The method of the invention includes the transmission (in a separate program of a transport stream) of a video stream representing a mosaic picture, the sub-pictures of which are miniature versions of the video stream of other programs in that transport stream. The method further includes the transmission of information which links the position of each sub-picture within the mosaic picture with the program number from which the sub-picture is derived. The user selects a desired program by merely `pointing and clicking` its miniature version in the mosaic picture.

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Eindhoven, Netherlands

Jurgen F Rosengren