Editing Mean Opinion Score (section)

=== Standardization ===

The methodology was formally standardized in ITU-T Recommendation P.800, "Methods for subjective determination of transmission quality," approved on August 30, 1996.<ref>https://www.itu.int/rec/T-REC-P.800-199608-I/en</ref> This recommendation established rigorous protocols for conducting subjective quality tests, including specific requirements for test environments and procedures.

The standardization specified that test subjects should be seated in quiet rooms with volumes between 30 and 120 cubic meters, reverberation times less than 500 milliseconds (preferably 200-300 ms), and room noise levels below 30 dBA with no dominant spectral peaks. These environmental controls ensured consistency and reliability in MOS evaluations across different testing facilities and organizations.