Abstract idea of Song instead of pure file management

[Jud Craft]

I was impressed how good the feature sounds. :D  I hope something
excellent may come of this.

The corner-corner case of "tag data is correct, but incomplete (no
year)" is very tricky, but an unfortunate consequence, I think.  Both
incomplete tag-data and the degeneracy of sound-analysis for similar
yet truly different files are a catch-22, but I would not call them
showstoppers.

A perk of tag-identification:  you can _fix_ the tags. :)


That brings up one last point -- under the Sources tab, you should be
able to alter the tags of one particular file.

I think this can actually be a clever extension of Amarok's "Edit Tags
in Files" tool -- use this tool to edit tags on individual files, yet
for the abstracted Song, the user is actually editing all tags of the
Source files simultaneously (multi-file tagging, which is a capability
already implemented, I believe, so you save work there).

So whereas the song metadata under Song Properties is secretly
changing the metadata for all files at once, you can still go and edit
each file's tags individually under the Sources tab.

The Sources tab should have some sort of disclaimer for the user (ie,
"These files have been identified as providing the song [Song Name] by
their tag data.  If this is incorrect, you may fix the tag data on
these files.")  And perhaps, accompanying the Sources list, is a
button below "Edit File Tag Data", which will open the tag edit box
for that file.

Feel free to correct and give criticism; I am no UI-design guru.  My
idea is just to make it as simple as possible while covering all
necessary functionality.