ATIS - Alliance for Telecommunications Industry Solutions
Scope
This Technical Report specifies a number of normalization methods suitable for use with objective video quality metric (VQM) methods based on availability of the full reference video signal. Such measurement methods are double-ended and utilize normalization as shown in Figure 1. Normalization means that time-invariant systematic changes in the video@ from reference input to processed video output@ are removed prior to performing full reference video quality measurements. Normalization is required because most full reference methods compare reference and processed pictures on what is effectively a pixel-by-pixel basis. Only time-invariant static changes in the video are removed@ dynamic changes due to the compression and decompression processes are measured as part of the quality rating calculation. Normalization adjusts the processed video input to the measurement in a manner similar to that expected for delivery to the final viewer or as required for operation of the VQM. Table 1 lists the parameters that may be normalized. See 1.3 for specific applications and limitations of the methods described in this Technical Report. Normalization is shown in Figure 1 as a separate block in a video quality measurement system in order to explain the application of the normalization methods in this Technical Report. Full reference video quality measurement methods do not require a specific normalization method@ only one that provides results meeting a specified degree of accuracy. Such normalization methods would usually be incorporated in the implementation of the full reference video quality measurement. Therefore@ normalization method(s) described in this Technical Report may optionally be used with full reference video quality metrics. Purpose This Technical Report describes video normalization methods that may be used in conjunction with video quality metrics utilizing the Full Reference technique. Full reference video quality measurement methods are necessary to support the interconnection and interoperability of telecommunications networks at interfaces with end-user systems@ carriers@ information and enhanced-service providers@ and customer premise equipment. Application Applications of the normalization methods described in this Technical Report are limited to specific video signals and sequence lengths as described below in order to meet the immediate need for documentation of available video quality metrics and to coordinate with available validation test methods.