It uses the resid library, and compresses as it transcodes, so the performance seems to be around 50% of realtime. My implementation of the Enhanced Sidplayer file format is incomplete, mostly in the areas surrounding the Modulation commands. I haven't run it in a loop across the entire CGSC database or anything, but it does seem to handle most files I throw at it by process of random selection. I suspect all of the most popular commands are now implemented. A bit lightly tested in the filter area, tho, sorry.
I'm putting the source code up (OS X only, sorry) for a command line version of the converter at http://files.me.com/henrik511/to6j9p . If you specify a music package name, it will look for any .mus, .str files, and build a mono or stereo .m4a file. So, for instance, if you have Two_Part_Invention.mus and Two_Part_Invention.str and you give the command "ConvertFile Two_Part_Invention", it should generate "Two_Part_Invention.m4a".
This is slightly better than the current SidPlay solutions for three reasons:
* It knows when to stop playing, so you don't have to babysit it.
* It is geared to conversion, so you only have to do this once
* It works with the CGSC collection rather than the HVSC collection, so it does real music rather than game music
It is slightly worse because:
* It has no GUI
* It's a bit of hack into the ConvertFile sample demo, not a proper application
If there's real interest, I'll keep working. If not, it meets my needs, and I'll just convert the CGSC for my own use.