Online Audio annotation tools
I'm not sure if it meets all your criteria (mostly because I'm not sure I understand all your criteria!), but you could have a look at ELAN:


  Description: With ELAN a user can add an unlimited number of textual
  annotations to audio and/or video recordings. An annotation can be a
  sentence, word or gloss, a comment, translation or a description of
  any feature observed in the media. Annotations can be created on
  multiple layers, called tiers. Tiers can be hierarchically
  interconnected. An annotation can either be time-aligned to the media
  or it can refer to other existing annotations. The content of
  annotations consists of Unicode text and annotation documents are
  stored in an XML format (EAF).


See also the Wikipedia page about ELAN. There is also a Wikipedia list of related software, I don't know if this is relevant.