Many organizations have focused on developing digital video quality metrics which produce results that accurately emulate subjective responses. However, to be widely applicable a metric must also work over a wide range of quality, and be useful for in-service quality monitoring. The Institute for Telecommunication Sciences (ITS) has developed spatial-temporal distortion metrics that meet all of these requirements. These objective metrics are described in detail and have a number of interesting properties, including utilization of 1) spatial activity filters which emphasize long edges on the order of 1/5 degree while simultaneously performing large amounts of noise suppression, 2) the angular direction of the spatial gradient, 3) spatial-temporal compression factors of at least 384:1 (spatial compression of at least 64:1 and temporal compression of at least 6:1, and 4) simple perceptibility thresholds and spatial-temporal masking functions. Results are presented that compare the objective metric values with mean opinion scores from a wide range of subjective data bases spanning many different scenes, systems, bit-rates, and applications.

Spatial-temporal distortion metric for in-service quality monitoring of any digital video system

Mean Opinion Score (MOS) tests are a well-known procedure to indicate the suitability of telecommunications equipment to provide voice services. However, converged data networks provide a variety of services, increasingly entertainment services as e.g. games. After describing the potential of games for Third Generation (3G) mobile networks, this paper establishes first guidelines to perform subjective assessment of game quality. Subsequently, an experimental study is conducted to assess the game quality of a multiplayer real-time game, XBlast, for different network conditions.

Subjective quality assessment for multiplayer real-time games

This paper presents an overview of some existing techniques of Quality of Service QoS and Quality of Experience QoE. QoS stands for the quality of the network in terms of transporting data with a minimum of delay and packet loss and a maximum of bandwidth. The extremum values depend surely of the provided service. QoE defines the quality perceived by the user and is assessed at the terminal level. It can be computed through objective and subjective ways. A comparison of the two techniques as well as an improvement of the service by combining them are also addressed.

A brief synthesis of QoS-QoE methodologies

A novel high-quality, low-complexity dual-rate 4.7 and 6.5 kbits/s algebraic code excited linear predictive codec is proposed for adaptive multi-mode speech communicators, which can drop their source rate and speech quality under network control in order to invoke a more error resilient modem amongst less favorable channel conditions. Source-matched binary Bose-Chaudhuri-Hocquenghem (BCH) codecs combined with unequal protection diversity- and pilot-assisted 16and 64-level quadrature amplitude modulation (16-QAM, 64-QAM) are employed in order to accommodate both the 4.7 and the 6.5 kbits/s coded speech bits at a signaling rate of 3.1 kBd. Assuming an excess bandwidth of 100%, in a bandwidth of 200 kHz 32 time slots can be created, which allows us to support in excess of 50 users, when employing packet reservation multiple access (PRMA). Good communications quality speech is delivered in an equivalent bandwidth of 4 kHz, if the channel signal-to-noise ratio (SNR) and signal-to-interference ratio (SIR) of the benign indoors cordless channel are in excess of about 15 and 25 dB for the lower and higher speech quality 16-QAM and 64-QAM systems, respectively, and the PRMA time-slots are sufficiently uninterfered due to using time-slot classification algorithms and due to the attenuation of partitioning walls and ceilings. >

/pdf/an-intelligent-multimode-voice-communications-system-for-7jp9ky76u2.pdf

An intelligent multimode voice communications system for indoor communications

The Research Centre of RAI (Radiotelevisione Italiana) is developing studies to find a correlation between objective measurements of video impairments and human perception. Such measurements should allow subjective assessments without human input. This paper presents the preliminary results of two attempts at correlation between a set of objective measurements and subjective assessment carried out on a number of images under varying compression systems.

http://ieeexplore.ieee.org/iel7/7227860/7243636/07243646.pdf

Correlation between objective and subjective measurements for video compressed systems

With the deregulation and emergence of new telecommunication providers in many countries, national and international standards committees have assumed increased responsibility for the cooperative planning of new technology development and the matching of multivendor service offerings with user needs. One important focus of this effort has been the standardization of user-oriented, technology-independent measures of telecommunication service quality. The standardized measures will be used by providers to design and implement telecommunication systems and services, and by users to define telecommunication requirements and select the products that most effectively meet them. The authors discuss in particular call processing, data communication quality, video and voice quality measures. >

N.B. Seitz

Papers

User-oriented measures of telecommunication quality