Spirent Communications has integrated “V-Factor” into its IPTV Quality of Experience (QoE) Test System. V-Factor, developed by QoSmetrics, is an implementation of the Moving Picture Quality Metric (MPQM) standard for network-delivered video assessment and displaces the older, primitive Media Delivery Index (MDI) approach.
Hitachi is one of the first IPTV network equipment manufacturers to employ Spirent’s V-Factor enabled test system.
The Spirent IPTV QoE Test System along with V-Factor technology determines video quality as perceived by a subscriber and offers a high correlation with user’s actual quality of experience.
V-Factor, which also includes audio performance assurance, takes into account network impairments such as delay variation and packet loss episodes that impact the video buffer used to restitute a video image as well as image complexity and the type of codec used. The technology enables the service provider to understand how network performance issues impact this perceived quality, in advance of the service being launched. Obsolescent testing metrics such as MDI merely attempt to infer subscriber QoE based on network performance indicators.
V-Factor is an objective measurement system that reproduces the subjective experience of the human observer. Network-based metrics are only capable of suggesting a coarse grade of subscriber QoE and are not sufficient for performance evaluation of video services like IPTV, especially in the context of a highly competitive broadband video market. MPQM, by comparison, is based on an objective evaluation method that is capable of filtering network-induced quality of degradation by properties of human vision.
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