Abrégé

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.

Classes IPC  ?

• H04N 17/00 - Diagnostic, test ou mesure, ou leurs détails, pour les systèmes de télévision

Abrégé

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.

Classes IPC  ?

• H04N 21/647 - Signalisation de contrôle entre des éléments du réseau et serveur ou clients; Procédés réseau pour la distribution vidéo entre serveur et clients, p.ex. contrôle de la qualité du flux vidéo en éliminant des paquets, protection du contenu contre une modification non autorisée dans le réseau ou surveillance de la charge du résea
• H04N 19/124 - Quantification
• H04N 19/14 - Complexité de l’unité de codage, p.ex. activité ou estimation de présence de contours
• H04N 19/182 - Procédés ou dispositions pour le codage, le décodage, la compression ou la décompression de signaux vidéo numériques utilisant le codage adaptatif caractérisés par l’unité de codage, c. à d. la partie structurelle ou sémantique du signal vidéo étant l’objet ou le sujet du codage adaptatif l’unité étant un pixel
• H04N 17/02 - Diagnostic, test ou mesure, ou leurs détails, pour les systèmes de télévision pour les signaux de télévision en couleurs

Abrégé

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.

Classes IPC  ?

• H04N 19/89 - Procédés ou dispositions pour le codage, le décodage, la compression ou la décompression de signaux vidéo numériques utilisant le pré-traitement ou le post-traitement spécialement adaptés pour la compression vidéo mettant en œuvre des procédés ou des dispositions de détection d'erreurs de transmission au niveau du décodeur
• H04N 19/159 - Type de prédiction, p.ex. prédiction intra-trame, inter-trame ou de trame bidirectionnelle
• H04L 1/24 - Tests pour s'assurer du fonctionnement correct

Abrégé

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.

Classes IPC  ?

• H04L 25/03 - Réseaux de mise en forme pour émetteur ou récepteur, p.ex. réseaux de mise en forme adaptatifs

Abrégé

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.

Classes IPC  ?

• H04L 45/02 - Mise à jour ou découverte de topologie
• H04L 45/12 - Routage ou recherche de routes de paquets dans les réseaux de commutation de données Évaluation de la route la plus courte
• H04L 12/14 - Dispositions pour la taxation

Abrégé

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.

Classes IPC  ?

• H04L 45/02 - Mise à jour ou découverte de topologie
• H04L 45/12 - Routage ou recherche de routes de paquets dans les réseaux de commutation de données Évaluation de la route la plus courte
• H04L 12/14 - Dispositions pour la taxation

Abrégé

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.

Classes IPC  ?

• H04L 12/28 - Réseaux de données à commutation caractérisés par la configuration des liaisons, p.ex. réseaux locaux [LAN Local Area Networks] ou réseaux étendus [WAN Wide Area Networks]
• H04L 43/0864 - Retards de voyage aller-retour
• H04L 43/50 - Disposition de test
• H04L 67/1008 - Sélection du serveur pour la répartition de charge basée sur les paramètres des serveurs, p.ex. la mémoire disponible ou la charge de travail
• H04L 67/101 - Sélection du serveur pour la répartition de charge basée sur les conditions du réseau
• H04L 67/1012 - Sélection du serveur pour la répartition de charge basée sur la conformité des exigences ou des conditions avec les ressources de serveur disponibles
• H04L 67/1023 - Sélection du serveur pour la répartition de charge basée sur un hachage appliqué aux adresses IP ou aux coûts
• H04L 41/0896 - Gestion de la bande passante ou de la capacité des réseaux, c. à d. augmentation ou diminution automatique des capacités
• H04L 41/50 - Gestion des services réseau, p.ex. en assurant une bonne réalisation du service conformément aux accords
• H04L 43/16 - Surveillance de seuil
• H04L 67/1001 - Protocoles dans lesquels une application est distribuée parmi les nœuds du réseau pour accéder à un serveur parmi une pluralité de serveurs répliqués

Abrégé

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.

Classes IPC  ?

• H04L 65/80 - Dispositions, protocoles ou services dans les réseaux de communication de paquets de données pour prendre en charge les applications en temps réel en répondant à la qualité des services [QoS]

Abrégé

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.

Classes IPC  ?

• C03C 13/04 - Fibres optiques, p.ex. compositions pour le cœur et la gaine de fibres

Abrégé

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.

Classes IPC  ?

• C03C 13/04 - Fibres optiques, p.ex. compositions pour le cœur et la gaine de fibres