Quality of Experience (QoE) for Internet Streaming Video is the estimation of a provider’s service quality from a customer’s point of view. QoE values are used to monitor quality of a service and quantify the improvements to customer experience before they complain or leave.
The value of QoE for an audio or video stream is defined as:
with Quality of the Network Delivery System, Quality of Encoding to the network, Quality of Decoding from the network, Human factors, and number of units or customers.
Mean Opinion Score (MOS) is a measure of service quality that was originally designed for digital phone systems. MOS is a qualitative measurement calculated by having many users rank phone calls from 0 to 5 (5 being the best). Objective measurements of the service (such as peak signal-to-noise ratio) can be mapped to MOS, and MOS can be mapped to QoE.
IP Networks are widely used for media transport between end points. The expectations of customers are not changed, and may even increase, after starting to use voice and video over IP, since new technologies should have a higher quality. However, Internet and other IP networks present additional challenges to the Service Provider. IP packets transferred through the network are non-deterministic and can be dropped. Packet loss and jitter are potential problems for QoE of voice and video over IP.
The Media Delivery Index (MDI) is a new measure dedicated to monitoring voice and video over IP services for the component of QoE they have under their control. The MDI can be used to passively or activity monitor live voice and video over IP networks. It is measured per media stream and can be measured constantly for complete coverage of the media service.
The value of QoE for voice or video over IP can be defined as:
with Quality of MDI per stream, Quality of Encoding to the network, Quality of Decoding from the network, Human factors, and number of units or customers.
MDI provides the user an indicator of IP cumulative jitter and packet loss. MDI could be expressed as a Delay Factor (DF) and a Media Loss Rate (MLR). DF is the amount of time the media stream will need to buffer account for jitter and the payload decode rate. MLR tracks the amount of media lost per second. The service provider is able to evaluate the network performance at any point in the network by measuring the DF and MLR for both voice and video streams.