SPC timers not being read accurately by foo_snesapu by Lunar at 10:32 AM EDT on October 14, 2020
I've used foo_snesapu before now, but reverted back to foo_gep on those occasions because it isn't good for tagging. Now that I'm using External Tags for all of my music library I thought it'd be worth trying it again, and so far it is working well in 99% of cases. However, making the switch threw up some problems with timers not being read on a small minority of sets and files that I didn't have problems with using foo_gep. Mainly, the problematic files yield timers at a length of 15:59, or 959 secs with 59999ms fade.
In most cases, I was able to fix the sets with broken timers by simply redownloading them from joshw or snesmusic, however some files (e.g. these sets for Leading Company and Special Tee Shot) have broken timers in foo_snesapu from the word go. Another fringe example is this set for Utopia, where despite track #2 clocking in at 18:02, the default of 15:59 is again returned.
I don't know enough about the intricacies of the SPC tag format to know what's amiss, and my usual tactic of deleting external tags and reloading tag information has not helped. In these minority of cases where redownloading files isn't an option, what should I do to get the timers read correctly by foo_snesapu?
After much head-scratching I solved my problem. It requires hex-editing.
foo_snesapu does not tolerate the emulator flag in the SPC Header (0xD2) being a null value, this causes it to mishandle the timers in the way that I explained above. Fix: edit 0xD2 to "0" rather than null in affected files.
I realise this isn't a very popular SPC player but maybe this information is useful to someone other than myself.