Different MDPs support different file types and metadata fields. When requesting metadata fields, you must state the metadata categories and the individual attributes that you want to retrieve; see mmmd_get() for more details.
The libmd library combines a category (the prefix) with each of the listed attributes (the suffixes) to form the full names of the metadata fields. You can state as many categories and attributes as you need but you should be aware of which fields are supported by which MDPs.
The MDPs shipped with libmd and the file types and metadata that they support are as follows:
MDP | Files | Metadata categories | Attributes |
---|---|---|---|
CDDA | CD audio tracks | md_title | album, artist, genre, name, composer, track, bitrate, samplerate, duration, format |
Exif | POSIX files on mass storage devices (e.g., USB sticks) | md_title | width, height, date_time_original, shutter_speed, fnumber, iso_speed_ratings, focal_length, orientation, description, latitude, longitude, keywords |
Extart | External artwork such as cover images for albums and thumbnail graphics for tracks | md_title | art (see 1) |
md_artwork | image (see 2), count, size, urls | ||
IMG | Image files | md_title | width, height, color_depth |
iPod | iPod media files | md_title | art (see 1) |
md_artwork | image (see 2), mimetype, width, height, size, count | ||
MediaFS | Files on MTP devices | md_title | name, artist, album, composer, genre, year, duration, comment, protected, track, art (see 1) |
md_artwork | image (see 2), width, height, size, mimetype, count | ||
MMF | MMF files accessible from either a network source (e.g., an HTTP server) or a POSIX device | md_title | name, artist, album, albumartist, composer, genre, comment, duration, track, disc, year, seekable, pausable, samplerate, bitrate, protected, mediatype (see 3), width, height, art (see 1), compilation, rating |
md_video | width, height, pixel_width, pixel_height, frame, fourcc | ||
md_audio | fourcc | ||
md_artwork | image (see 2), description, type, mimetype, count, size |