Often, a single APE or FLAC file contains a complete ablum. We can still
play next or previous track in the ablum with the help of
emms-cue.el package, provided there is a corresponding cue sheet
file. This package also defines emms-info-cueinfo for retreiving
the track information for APE / FLAC itself.
To load emms-cue.el:
(require 'emms-cue)
(add-to-list 'emms-info-functions 'emms-info-cueinfo)