Abstract: A method is provided for determining, from DCT coded data used in MPEG video coding, the number of bits required to represent an output value which would be obtained after an inverse transform is performed on said transform coded data. The method comprises obtaining a sum of coefficient values within said transform coded data (204) and comparing this sum to a predetermined threshold value (206). As a consequence of said comparison a processor decides which inverse transform implementation, out of a number of pre-determined implementations, should be performed when decoding said transform-coded (208,210). For example, eight bit-processing routines may be used, which are more economic than nine bit routines if the sum is less than a threshold value.

Abstract: An MPEG decoder (100-180) can use different formats (linear tiled etc) for image data memory (150) for reference pictures when decoding subsequent pictures. Each format brings advantages and disadvantages. The disclosure illustrates that it is possible for different video sequences to have characteristics which match one image buffer format well, but not another, for example where there is a lot of motion or only a little motion between images. Advantageously, the decoder employs a parameterised image buffer format and analysis of the incoming stream and/or measured decoding performance (190) so as to dynamically choose (90, 160, 170) the best image buffer format for the current part of a stream. Cache control features can also be controlled (198) to suit the particular data received.

Abstract: An image control system for controlling a menu on a display, comprises a menu arranged as a plurality of simultaneously displayed menu items in a loop and a selector (12) to select an item from the menu, the loop and the selector being moveable with respect to each other. A user input device (4) comprises a control device (6; 16) to generate a control signal to move the loop and the selector (12) relative to each other. The control device (6; 16) has a loop configuration, with movement around the loop of the control device causing corresponding relative movement between the selector (12) and the loop of the menu. Correlation between the loop configuration of the control device and the loop of menu items enables a user to intuitively navigate around a menu of items and select a desired one.

Abstract: An appliance, such as a set top box, has an ON power mode and a STAND BY power mode and is in communication with a television set. A parameter of an operating signal associated with the television set is monitored and the value of the parameter is compared with predetermined values at which the set top box is desired to be either operative (ON power mode) or inoperative (STAND BY power mode). When a predetermined value of the parameter is detected, the current power mode of the set top box is evaluated and, if necessary, changed. Power supply to the TV set, operating frequency of a local oscillator/mixer in the TV set or the presence of a line scan signal from the TV set rate can be monitored to determine whether the appliance should be turned on or off.

Abstract: A portable computer device has data acceptance logic (24,40) that determines whether input data items have time and location information. If not, data items are stored together with time and location information taken from clock (30) and location determining circuitry (28), here a Global Positioning Service (GPS) system. A screen (6) is arranged to display data items in a time mode or a space mode. In the time mode, those data items with time information in a time interval are displayed on a time line. In a space mode, data items with time information in a display area are displayed, for example on a map of the display area. The display can be toggled between the time and space modes.

Abstract: There is provided transmission of MPEG2 audio and data over an in-house wireless network using the 802.11b standard with a Home Media Centre to tune and store a number of TV and audio streams for distribution to a number of client devices throughout a home. A transrater reduces the bit rate for use in the limited bandwidth wireless communications network. Prioritisation of the data packets for resending is made according to content format and/or age.

Abstract: A router at the head-end of the broadest system or mobile network caches all TCP/IP packets that pass. The router periodically resends any data packets, from its cache, which are not received at the client. The system allows TCP/IP to be easily implemented without causing significant amounts of back traffic being generated, while maintaining the same interfaces.