Absolute Category Rating (ACR) is a test method used in quality

Video quality

Video quality is a characteristic of a video passed through a video transmission/processing system, a formal or informal measure of perceived video degradation...

 tests. It has been standardized in ITU-T

ITU-T

The ITU Telecommunication Standardization Sector is one of the three sectors of the International Telecommunication Union ; it coordinates standards for telecommunications....

Recommendation P.910. In this method, a single test condition (generally an image or a video sequence) is presented to the viewers once only. They should then give a quality rating on an ACR scale. Test conditions should be presented in random order.