Hi,
Thanks for the proposal. I already wrote a little bit about our ideas for search here: Search API for acousticbrainz
Please take a look at it and see if you have any additional comments.
There is a difference between the items you listed in your features, and the ideas that you listed. The features are quite easy to do with any text search system. As I mentioned in the previous post we have already done this with elasticsearch.
My feeling is that your ideas on relevance would be better suited to content-based search rather than text search. This is quite a different project, but really interesting. There are some related projects listed on the AcousticBrainz ideas page, including Content-similarity, Data description, and Spot the odd song out.
We have a sound similarity search system in Freesound, which uses Gaia, the same technology we use in AcousticBrainz to perform our machine learning processes. For example, see a similar sounds page. Do you think this kind of similarity could also be done for songs, not just short sounds?
Finding clusters of songs is a cool idea. It would be interesting to see if these clusters could be used to discover if two submissions in AcousticBrainz have different MBIDs but are in fact the same song.
What about clustering at a broader level? If we tried to cluster on mood, song “colour”, instrumentation, style, etc, how would you go about gathering ground truth descriptors to understand what these clusters mean?