From Bright Pattern Documentation
< 5.3:Faq
Hold Music
What format can be used for hold music?
Bright Pattern currently supports .WAV files in the following format: G.711 μ-law mono 8 KBPS format. Although we do not currently support MP3 files or stereo audio, support for stereo audio and additional file types will be added at a later time.
Hold music is uploaded in the Contact Center Administrator application, section Audio Treatments.