[vlc-devel] (no subject)

Jean-Baptiste Kempf jb at videolan.org
Wed Jan 15 19:32:31 CET 2014

On 15 Jan, Wieland Hoffmann wrote :
> Hallo Jean-Baptiste Kempf:
> > On 14 Jan, Wieland Hoffmann wrote :
> > > The MusicBrainz *Album* ID that the current code uses is not what's gets
> > > used for vlc_meta_TrackID (the UFID frame in ID3). The TrackID
> > > corresponds to the MusicBrainz Recording ID, where a recording is a
> > > peace of audio that later gets used as a track on one (or more) releases
> > > (albums). The "official" definition of a recording is at [0].
> > 
> > OK, then I'm confused. Great.
> > What does acoustid return then?
> Now that you've brought AcoustID into the conversation, I'm confused as
> well.

Excellent :)

> What the 00_musicbrainz.lua script does is: it gets the MusicBrainz
> Album ID (which is the ID for an album or, as it's called in MB, a
> release [0]). To query the web service for output that indicates whether
> or not the Cover Art Archive (CAA) has artwork for the release, it's
> necessary to know the Album ID [3]. Finding that ID can happen through either

Could it do it with just the TrackID?

> * searching for the release on MB with some known metadata like the


> * getting the MusicBrainz Album ID directly from the tags of the audio

> * Fingerprinting the audio files (which does not need to have any


We need to support all of those.

> Now that we've got the MBID of the album, the existing try_query
> function in share/lua/meta/art/00_musicbrainz.lua will work.


> > OK. What do you suggest then?
> The only problem in my explanation above is that currently, the Album ID
> is not read from some files, even if the tags do actually contain it.

That's bad©®.

> * add code to explicitly read the MusicBrainz {Album, Artist, Work,
>   Album Artist} ID from the files. This is relatively easy because it
>   boils down to asking taglib for the tag in readMetaFrom* and, if it
>   exists, add it somewhere (either extra_tags or by extending
>   vlc_meta_type_t). Adding it into extra_tags would mean that the
>   MusicBrainz related tags do appear in the metadata dialog, but other
>   tags that VLC doesn't know about do not.


> * extend the respective readMetaFrom* methods to read *all* tags taglib
>   gives us. That would mean adding a check like "has the tag that we're
>   deadling with right now already been handled by populating ppsz_meta
>   of vlc_meta_t (the well known tags like artist, album, etc.)".

Hmm, we would still need the mapping.

> In that case, I think it'd be best to normalise the names for the MBIDs
> or use vlc_meta_type_t - otherwise, we'd need to change the display
> logic depending on the file type.

What I hear also is that storing the TrackID is of limited used compared
to the MBID...

Other good modification you recommend?

With my kindest regards,

Jean-Baptiste Kempf
http://www.jbkempf.com/ - +33 672 704 734
Sent from my Electronic Device

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