Psytechnics Limited

Netscout Systems, Inc.

Simon Richard Broom

Paul Alexander Barrett

Richard Jb Reynolds

Marc Isambart

Paul Barrett

Ludovic Christophe Malfait

Richard John Buchan Reynolds

Xiao-Si Wang

James Schofield

A method for assessing perceived quality of adaptive media streaming includes receiving, by a device including a processor, a stream of adaptive media content. This stream includes both audio signals and video signals. A number of quality change events in the received stream for a predetermined period of time is determined. Also, a difference value between a highest quality level value detected in the received stream for the predetermined period of time and a lowest quality level value detected in the received stream for the predetermined period of time is determined. A quality impact score value is generated for the received stream based on the determined number of quality change events and based on the determined quality level difference value.

Method for assessing the perceived quality of adaptive video streaming

Systems and methods are described for determining a set of three quality metrics for audio and/or video signals transmitted through a packet network. The set of three metrics provide more insight into which factors are affecting the quality of the received signal as perceived by the end-user. These three quality metrics measure reductions in quality due to lossy media transmission, packet loss concealment from packet loss and/or packet/frame jitter, and long periods of silence and/or frozen video. Because each metric quantifies a different aspect of transmitted quality, a deficiency in the transmitted signal can be identified by reference to the set.

System and method for diagnostic modeling of audio and video quality of service

This invention relates to a method of defining an optimised set of test sequences for use with a packet based perceptual quality evaluation processor associated with an edge-device that receives packets containing speech data and converts said packets to a speech signal, the method comprising the steps of: defining a set of quality targets which should be produced when a test sequence of packets is processed by the edge-device; determining a value for a degradation parameter for each quality target wherein a test sequence having a degradation according to said value will substantially produce said quality target when said test sequence is processed by the edge-device.

Generating test sets

The present invention relates to the problem of estimating the effect of packet transmission impairments, including packet loss, on the subjective quality of a video transmission where frames of data relating to the same video frame or field are permitted to span more than one packet. The invention provides a method of assessing quality of a video signal comprising a sequence of video frames received via a packet switched network using a parameter which is a weighted sum of two counters where the first counter is incremented in dependence of the total number of packets in frames determined to have been received with one or more lost packets and the second counter is incremented in dependence of the number of packets following the first lost packet in each frame and the lost packet itself.

Video quality assessment

This invention relates to a non-intrusive video quality assessment system. A method and apparatus are provided in which video frame parameters are extracted from a sequence of packets by generating a first video quality parameter for each group of packets associated with a particular frame of video data in dependence upon the frame rate of the video stream; and generating a second video quality parameter for each of said group of packets in dependence upon the size of encoded data comprising the video frame.

Non-intrusive speech quality assessment method and apparatus for storing a sequence of intercepted packets associated with a call, each packet containing speech data, and an indication of a transmission time of the packet; storing with each intercepted packet an indication of an intercept time of the packet; extracting a set of parameters from the sequence of packets; and generating an estimated mean opinion score in dependence upon the set of parameters. The extracting step comprises the sub steps of: generating a jitter parameter for each packet of the sequence of stored packets; generating a long term average jitter parameter for the stored packet; and generating a differential jitter parameter in dependence upon the jitter parameter for the stored packet and the long term average jitter parameter.

Quality assessment tool

Non-intrusive speech quality assessment method and apparatus for: storing a sequence of intercepted packets associated with a call, each packet containing speech data, and an indication of a transmission time of the packet; storing with each intercepted packet an indication of an intercept time of the packet; extracting a set of parameters from the sequence of packets; and generating an estimated mean opinion score in dependence upon the set of parameters. The extracting step comprises the sub steps of: generating a jitter parameter for each packet of the sequence of stored packets; and generating a consecutive positive jitter parameter for the stored packet.

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Suffolk, United Kingdom

Simon Richard Broom