Visual Media Coding and Transmission

2.6 Assessment of Video Quality

Video quality can be assessed using two types of technique: subjective assessment and objective assessment. Subjective tests are performed by asking viewers to give their opinion on the quality of videos that they are shown. Objective tests use a mathematical algorithm to produce a numerical quality rating.

Clearly, subjective tests are much more difficult to obtain as they require a significant amount of resources, in terms of people and time. However, they are capable of providing a better indication of quality than any of the objective measures currently in use. This is particularly true for 3D video quality assessment.

This section describes methods for subjective and objective quality assessment.

2.6.1 Subjective Performance Evaluation

Any subjective test for video should ideally respect the ITU-R BT.500-11 (‘Methodology for the Subjective Assessment for the Quality of Television Pictures’) standard [32]. Several subjective quality-assessment methods are described in the standard. It is essential to select the methods that best suit the objectives and circumstances of the assessment problem at hand. There are many criteria to be fulfilled in order to ensure that the evaluation tests are free from user- and environment-oriented inaccuracies. These include viewing conditions, monitor-related issues, source signal quality and characteristics, and test session issues.

Two of the main assessment techniques described within the standard are based ...