MP3 CUE

[dosboxonline]

bin/cue with CDAudio work fine. Possible mount with MP3 files?
Example cue file:
FILE "Horde.iso" BINARY
TRACK 01 MODE1/2048
INDEX 01 00:00:00
FILE "Track02.mp3" MP3
TRACK 02 AUDIO
PREGAP 00:02:00
INDEX 01 00:00:00
FILE "Track03.mp3" MP3
TRACK 03 AUDIO
INDEX 01 00:00:00
FILE "Track04.mp3" MP3
TRACK 04 AUDIO
INDEX 01 00:00:00

[dreamlayers]

I think this would work if you built with the SDL_sound library: https://www.icculus.org/SDL_sound/

Code here should handle it:

em-dosbox/src/dos/cdrom_image.cpp

Line 100 in e09c948

#if defined(C_SDL_SOUND)

I'm not aware of any port of SDL_sound for Emscripten, but that does not mean it can't be built. It might make more sense to use the browser's MP3 decoder, though that would require new code for interfacing to it.