Abstract

This invention is concerned with a video quality measurement method, in particular where the video signal having: an original form; an encoded form in which video signal has been encoded using a compression algorithm utilising a variable quantiser step size such that the encoded signal includes a quantiser step size parameter; and, a decoded form in which the encod-ed video signal has been at least in part reconverted to the original form. The method comprises the steps of: a) generating a first quality measure which is a function of said quantiser step size parameter; b) generating a masking measure and c) combining the first and second measures. The masking measure is which is a function of the spatial complexity of parts of the frames represented by the video signal in the decoded form, these parts being selected by generating a second measure which is a function of the pre-diction residual and identifying one or more regions of the picture for which the second measure exceeds a threshold.

IPC Classes  ?

• H04N 17/00 - Diagnosis, testing or measuring for television systems or their details

Abstract

This application is concerned with a non-intrusive video quality measurement method, in particular where the video signal having: an original form; encoded form in which video signal has been encoded using a compression algorithm utilising a variable quantiser step size such that the encoded signal includes a quantiser step size parameter; and, a decoded form in which the encoded video signal has been at least in part reconverted to the original form. The method comprises the steps of : a) generating a first quality measure which is a function of said quantiser step size parameter; b) generating a second quality measure which is a function of the spatial complexity of the frames represented by the video signal in the decoded form; and, c) combining the first and second measures in order to obtain an estimate for the subjective visual quality of the decoded video.

IPC Classes  ?

• H04N 21/647 - Control signaling between network components and server or clients; Network processes for video distribution between server and clients, e.g. controlling the quality of the video stream, by dropping packets, protecting content from unauthorised alteration within the network, monitoring of network load or bridging bet
• H04N 19/124 - Quantisation
• H04N 19/14 - Coding unit complexity, e.g. amount of activity or edge presence estimation
• H04N 19/182 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being a pixel
• H04N 17/02 - Diagnosis, testing or measuring for television systems or their details for colour television signals

Abstract

A video signal is coded by generating, at a transmitter, a difference signal (at 2) representing the differences between a picture to be transmitted and a predicted picture based on a stored locally decoded picture. This is decoded (5, 6) to generate a fresh locally decoded picture. The transmitter also generates a check signal, such as a CRC, as a function of the locally decoded picture. The receiver decodes the difference signal to create a decoded picture. It compares the decoded picture with the check signal, and generates an error signal if the two do not tally.

IPC Classes  ?

• H04N 19/89 - Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using pre-processing or post-processing specially adapted for video compression involving methods or arrangements for detection of transmission errors at the decoder
• H04N 19/159 - Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
• H04L 1/24 - Testing correct operation

Abstract

The present invention relates to a communication system having a central station and a plurality of outstations. The central station is configured to execute a compensation procedure for compensating for degradation of data from the outstations, the compensation procedure having a plurality of adjustable characteristics, which characteristics are governed by a parameter set. The central station stores a respective parameter set in respect of each outstation; and, for each outstation, applies the compensation algorithm to data from that outstation using the parameter set associated with that outstation. In an initialization phase, the central station tests a plurality of starting parameter sets on data from a given outstation and selects the set providing the best compensation. The selected set is stored for subsequent compensation of data from that outstation.

IPC Classes  ?

• H04L 25/03 - Shaping networks in transmitter or receiver, e.g. adaptive shaping networks

Abstract

The invention relates to data networks, and to nodes making up parts of data networks, arranged to derive information relating to the characterisation of paths taken by data travelling between nodes in the networks. Path characterisation information is fed back from a receiver of data to a provider of data, and informs nodes subsequently forwarding data of characteristics of the downstream path. Also described are routing and related controlling nodes and methods for using such path characterisation information to make informed routing and other decisions when forwarding data in a data network.

IPC Classes  ?

• H04L 45/02 - Topology update or discovery
• H04L 45/12 - Shortest path evaluation
• H04L 12/14 - Charging arrangements

Abstract

The invention relates to data networks, to nodes making up parts of data networks, and to information relating to the characterisation of paths taken by data travelling between nodes in the networks. Path characterisation information is arranged to be conveyed to nodes such that it may be used by nodes subsequently forwarding data. In particular the invention relates to nodes receiving such path characterisation information from upstream nodes, deriving therefrom information indicative of characteristics of a path downstream of said nodes, and using such information to make informed decisions such as routing decisions when forwarding data onward in data networks.

IPC Classes  ?

• H04L 45/02 - Topology update or discovery
• H04L 45/12 - Shortest path evaluation
• H04L 12/14 - Charging arrangements

Abstract

A system (20) and method by virtue of which a preferred data provider is selected from a plurality of data providers (30) by performing the steps of receiving a request for data from a client (10) together with client identification data, identifying a plurality of data providers (30) capable of providing data to the client (10), providing the client identification data to the data providers and instructing the data providers to perform tests in order to establish a measure of the elapsed time for a signal to be sent to and received from the client, and a measure indicative of their remaining capacity for data transfer, and to make these measures available to the system (20). One or more preferred data providers (30) may then be selected on the basis of the elapsed time signals and the remaining capacity signals from said data providers.

IPC Classes  ?

• H04L 12/28 - Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
• H04L 43/0864 - Round trip delays
• H04L 43/50 - Testing arrangements
• H04L 67/1008 - Server selection for load balancing based on parameters of servers, e.g. available memory or workload
• H04L 67/101 - Server selection for load balancing based on network conditions
• H04L 67/1012 - Server selection for load balancing based on compliance of requirements or conditions with available server resources
• H04L 67/1023 - Server selection for load balancing based on a hash applied to IP addresses or costs
• H04L 41/0896 - Bandwidth or capacity management, i.e. automatically increasing or decreasing capacities
• H04L 41/50 - Network service management, e.g. ensuring proper service fulfilment according to agreements
• H04L 43/16 - Threshold monitoring
• H04L 67/1001 - Protocols in which an application is distributed across nodes in the network for accessing one among a plurality of replicated servers

Abstract

Data to be transmitted over a network comprise a first part (perhaps audio) which is always to be transmitted and alternative second parts (perhaps video coded at different compression rates) of which one is to be chosen for transmission, depending on the current network capacity. In order to accommodate systems where (owing perhaps to the use of a congestion control mechanism such as TCP) the capacity available is initially undetermined, one firstly begins to transmit just the first part. When the network capacity becomes known (typically by monitoring the performance of the network in transmitting the first part), one of the alternative second parts is chosen and transmission of its commences. If desired this may initially be preferentially to, or to the exclusion of, further transmission of the first part.

IPC Classes  ?

• H04L 65/80 - Responding to QoS

Abstract

ABSTRACT GLASSES, METHODS FOR MAKING THEM, AND OPTICAL FIBRES CONTAINING THEM A glass suitable for use in optical fibre cores has a refractive index of 1.540-1.610, Na2O and B2O3 in a molar ratio of 1.05-2:1, 2-12 mole per cent BaO, 40-63 mole per cent SiO2, and 1.5-15 mole per cent ZrO2, the proportion of SiO2 and ZrO2 together not exceeding 65 mole per cent. The glass can be prepared in a highly reduced state by the use of CO and a redox buffering agent. The glass is especially suitable for the production of high numerical aperture wide cored fibres.

IPC Classes  ?

• C03C 13/04 - Fibre optics, e.g. core and clad fibre compositions

Abstract

ABSTRACT OXIDE GLASS COMPOSITIONS FOR USE IN OPTICAL FIBRES A oxide glass composition which consists of the following components: Na2O 17 to 21 mole % B2O3 14 to 20 mole % Al2O3 1 to 3 mole % MgO 1 to 3 mole % ZnO 1 to 3 mole % SiO2 47 to 66 mole % other oxides not more than 3 mole % This composition can be used as a cladding for low loss core compositions in optical fibres, and has high durability.

IPC Classes  ?

• C03C 13/04 - Fibre optics, e.g. core and clad fibre compositions