Revision of Rec. ITU-R BS.1534

In audio quality evaluation, ITU-R BS.1534-1, commonly known as MUSHRA, is widely used for the subjective assessment of intermediate audio quality. Studies have identified limitations of the MUSHRA methodology [1][2], which can influence the robustness to biases and errors introduced during the testing process. Therefore ITU-R BS.1534 was revised to reduce the potential for introduction of systematic errors and biases in the resulting data. These modifications improve the validity and the reliability of data collected with the MUSHRA method. The main changes affect the post screening of listeners, the inclusion of a mandatory mid-range anchor, the number and length of test items as well as statistical analysis. In this paper the changes and reasons for modification are given.