%% You should probably cite rfc8251 instead of this I-D.
@techreport{ietf-codec-opus-update-00,
    number =    {draft-ietf-codec-opus-update-00},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-ietf-codec-opus-update/00/},
    author =    {Jean-Marc Valin and Koen Vos},
    title =     {{Updates to the Opus Audio Codec}},
    pagetotal = 6,
    year =      2014,
    month =     jan,
    day =       13,
    abstract =  {This document addresses minor issues that were found in the specification of the Opus audio codec in RFC 6716 {[}RFC6716{]}.},
}