Ah-hah! I have finally found the bug that caused my mp3s to include a

Ah-hah!  I have finally found the bug that caused my mp3s to include a
bit of the next track at the end of one, but only sometimes.  The
hundredths of a second vs. sector was certainly a bug, but was not
this bug.

(get_decode_args): Use sprintf %02d for each field.  Previously i
was just stringing them together with colon and dot, so "9" becomes
"9" instead of "09", which flac sees as 90!