Hi, I played around with dir2ogg to adapt it to become a dir2neroaac (they offer a free-beer encoder now). I found dir2ogg’s approach very reasonable but I discovered a number of shortcomings. Fortunately I found the bazaar branch and can see that some of those were fixed, like not using pipes, and some of the duplication in the methods.
My main gripe remains, and that is the limitation to few canonical tags, when ideally all should be preserved. Other Projects like Quod Libet and Picard go so far to map tags in all formats to each other and use free form tags like TXXX frames in id3v2 or ----:com.apple.iTunes in MP4 for tags that have no canonical identifier in that format.
An example is in the mp4.py format definition of picard[1]. It loads all tags into a Metadata structure. I wasn't able to replicate this for dir2ogg yet since I haven't completely disentangled the classes of picard yet.
Say you rather use the grouping tag which is prominent in iTunes, than genre; it will be lost now. Or the Album Artist tag, which should definitely be preserved. There are many other examples, where the current solution will lead to data loss.
[1] http://codebrowse.launchpad.net/~luks/picard/qt-port/annotate/lalinsky%40gmail.com-20070818101632-2h55qo54kdi7m5ss?file_id=mp4.py-20060924101741-35v3ig7dle5glb6k-1
Still pondering on a solution. Here’s a tag mapping table:
http://