[lug] audio questions

Hugh Brown hugh at math.byu.edu
Fri May 9 07:21:23 MDT 2008

dio2002 at indra.com wrote:
>> the amarok gui makes retagging easy, it also has a "Script Manager" 
>> but I've never explored what it does/how it works.
>> for a command line oriented approach, I've used ogginfo, tagmp3, perl 
>> with the MP3::Info module, and metaflac to retrieve existing tags.
> good to know.
>> If the tags aren't there, those tools can also be used to put them there.
>> amarok does have a metadata db which supports sqlite3, mysql, and 
>> postgresql.  It writes the standard tags to the files themselves, but 
>> rating/ranking/last time played/etc. are stored in the db.
> that makes sense.  since it's pretty clear that the tags are inserted 
> into the files themselves, it's pretty obvious that playlists are 
> implemented in the metadata db of the given tool too, just like 
> rankings, etc.
> it would seem logical then that if you start moving files "outside" of 
> the interface provided by the medialib tool, you're going to screw up 
> the file pointers in the db for playlists and rankings.  which probably 
> means if you move collections from one device to another, that usually 
> requires a new import and recreation of playlists right?  or do the 
> tools have some intelligence to at least partially automate and recreate 
> the metadata like playlists, rankings when the underlying files are 
> moved around or to different devices?
> i'm also assuming most of these tools have the ability to export or 
> backup playlists that have taken lots of time to create.  but maybe not. 
>  preferably this functionality is built into the interface via an 
> 'export" option in addition to manually backing up a db in the 
> filesystem.  i was recently playing around with winamp and it looked 
> like you had to go out to the cmdline to do this.  on linux not a 
> problem but a pita on windows since it's harder to autoscript this.

Moving files outside of the interface can cause a loss of ranking. 
Saved playlists (in contrast to whatever the active playlist is) are 
just files and are not stored in the db.  You can also create 
conditioned playlists (rating >3 AND genre = ...).  There are a few 
pre-created ones too (e.g. all unrated music, never listened to, ...)

As amarok has gone through various upgrades, I have lost the db a few 
times.  I keep meaning to write a script to parse the db, pull the 
rating out and make it a tag in the flac/ogg files, but I haven't made 
time for it yet.

Once I import music into amarok, it doesn't usually leave, though I do 
copy files from the master collection out to external devices.  I also 
don't think of the music as fully processed until I've taken the time to 
make sure it is tagged the way I want it and put in the directory 
structure I want.


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