[Nepomuk] Bangarang player media library

[Jamboarder]

Thanks much for the heads up Evgeny.

> From: Evgeny Egorochkin
> I have uncovered another issue with Bangarang, It seems to have it's own media 
> library scanner and metadata extractor which also marks song metadata as user-
> created, and not automatically generated.

Bangarang doesn't really have an explicit media scanner function.  It just updates nepomuk whenever a file with extractable metadata is opened or when a user updates metadata for a media resource.  It uses the methods (setProperty, addType and setTypes) of Nepomuk::Resource to set/update data. Am I using the api incorrectly?

> 
> A much better solution would be to tell nepomuk which files to index and add  
> any of you custom data extractors into libstreamanalyzer or at least refactor 
> them as libstreamanalyzer plugins.

Sounds good. That makes sense for metadata that is techinically extractable from the file itself.  Since there's quite a lot of metadata that may or may not be extractable there will still be a need for Bangarang to maintain the in-context update of the nepomuk resource.  At the moment, when updating nepomuk data, Bangarang doesn't distinguish between techinically extractable file metadata and non-extractable metadata. Video metadata is the prime example.  The entirety of the the video metadata in Bangarang right now is user created. I hope to add some support of video file metadata formats in the 2.0 version.  I like the idea of refactoring the file metadata extractors as libstreamanalyser plugins, but I'll still need to maintain functionality for in-context user-created metadata that is not technically extractable.

> 
> You would get the same or better functionality, contribute to nepomuk and 
> avoid lots of pitfalls like your custom extractors and file indexing service 
> adding what essentially is 2 copies of the same data.
> 

That seems a little odd.  Does that mean a duplicate triple for the same resource is created when setProperty is called on an existing resource property? I can kinda see the reasoning for setting it to user-created but it seams like it shouldn't duplicate it.  Is there anyway for an app to just update the automatically generated triples since, whether strigi or Bangarang or any other app does it, the
data is still automatically generated from the file metadata. 

In the short term I'd like to sort out this duplicate issue as a potential bugfix.  Then, if it still makes sense, in the
medium term (version 2.0) I'd like to try for the libstreamanalyser
solution.

> I can help you with strigi part, and I hope Sebastian can find a way to let 
> Bangarang extend the media collection via some nepomuk API call.

Thanks much Evgeny.   A quick first thought is that since a libstreamanalyser plugin would result in a split in the code path for writing to nepomuk in Bangarang, to keep the user feedback consistent I'll probably need some progress feedback. Does that already exist?  Also, probably a silly question but can the plugin be delivered at app install time? Or does it have to be delivered at strigi install time?

peace and much respect,
Andrew