To convert .opus files to mp3, you may use Opus to Mp3 Converter
Opus is an open, royalty-free and highly versatile audio codec suitable for interactive speech and music transmission. Opus possesses higher audio quality compared with AAC, Vorbis and MP3 but Opus still has its limitations on compatibility with popular operating systems, applications, browsers, media players and audio editing programs.
Opus Window DirectShow lacks an Opus decoder. Google Android has added Opus support since version 5.0. Internet Explorer can not play Opus natively. Windows Media Player, iPod, iPhone, iPad, Android, PS3, Xbox 360, iTunes can not play Opus natively either. In order to overcome these limitations for convenient use of Opus on Window DirectShow, Google Android, Internet Explorer, Windows Media Player, iPod, iPhone, iTunes, etc the only choice is to convert Opus to MP3, WAV, FLAC, WMA, AAC and other popular audio formats. In order to convert Opus to MP3, WAV, FLAC, WMA, AAC and other popular audio formats efficiently we need a professional Opus converter – opus-to-mp3.com – is the best professional Opus Converter.