Abstract idea of Song instead of pure file management

[Jud Craft]

Basic problem:

There are many reasons to keep around multiple copies of a song, in
different formats.  Chiefly, you may prefer to keep a FLAC copy for
best quality, but an MP3 copy for your media players; and transcoding
on-the-fly every time for every song just isn't worth it.

You may even keep an OGG collection on your hard drive, while you have
higher-quality FLAC files stored on an extra drive at your
workstation.

When you attach to these sources of (identical songs, but different
formats) it would be ideal if suddenly your Amarok collection was not
populated with four or five different copies of the same song (as in
1.4).

It would be fantastic if the Amarok collection has the abstract idea
of a "Song entry", which can be matched to multiple files or sources
that actually provide the song.

For example, I would want to listen to the MP3 songs on my laptop.
But at home, hooked up to my docking station, I'd rather pump out the
pure FLAC files from my awesome speaker setup.  A type of
song-file-retrieval priority would be interesting.  I'd just click the
song, and Amarok would play whatever it has, with maybe a preference
for the better copy.

In addition, whenever you change one song from one format to another,
of course, most transcoding is not completely lossless:  going from
MP4 to MP3 or OGG to MP3 (for an iPod) may not be perfect, and it
would be shame to throw away the old file even though I want to use
the new one.  Having Amarok manage all file formats on a per-song
basis would help organize this greatly.

My current solution under old Amarok 1.4 is to keep separate albums.
The Beetles (OGG), The Beetles (FLAC), The Beetles (MP3).

But I think Amarok 2.0 could have a solution which is mostly low-key,
and very works-quite-well-by-default.  This shouldn't require tons of
extra configurations (should there be a user-customizable format
priority list for playing songs?) as some good common sense, and I
think this feature could be implemented in a way that is relatively
transparent to the user, but helps greatly with keeping a collection
tidy.

NOTE:  If Amarok 2 already has this idea underway then forgive my
redundancy; I am not a beta-tester, merely a well-wisher.