RetroPie BGM

import os
import time
import random
#import pygame # if you don't have pygame: sudo apt-get install python-pygame

#CONFIG SECTION
musicdir = '/home/pi/RetroPie/roms/music'
maxvolume = 0.75
volumefadespeed = 0.02
restart = True # If true, this will cause the script to fade the music out and -stop- the song rather than pause it.
#local variables
bgm = [mp3 for mp3 in os.listdir(musicdir) if mp3[-3:] == "mp3" or mp3[-3:] == "ogg"]
from pygame import mixer # import PyGame's music mixer
mixer.init() # Prep that bad boy up.

random.seed()
volume = maxvolume # Store this for later, we will make some nice fadeouts eventually.

#TODO: Fill in all of the current RetroPie Emulator process names in this list.
emulatornames = ["retroarch"]

#test: Ran into some issues, so we're camping for emulationstation.
esStarted = False
while not esStarted:
    time.sleep(1)
    pids = [pid for pid in os.listdir('/proc') if pid.isdigit()]
    for pid in pids:
        try:
            procname = open(os.path.join('/proc',pid,'comm'),'rb').read()
            if procname[:-1] == "emulationstatio":
                esStarted=True
        except IOError:
            continue

#ES Should be going.
while True:
    if not mixer.music.get_busy():
        song = os.path.join(musicdir,bgm[random.randint(0,len(bgm)-1)])
        mixer.music.load(song)
        mixer.music.set_volume(maxvolume) # Pygame sets this to 1.0 on new song; in case max volume -isnt- 1, set it to max volume.
        mixer.music.play()
        print "BGM Now Playing: " + song
    pids = [pid for pid in os.listdir('/proc') if pid.isdigit()]
    emulator = -1;
    for pid in pids:
        try:
            procname = open(os.path.join('/proc',pid,'comm'),'rb').read()
            if procname[:-1] in emulatornames:
                emulator = pid;
                #here is where we'd start muting the music.
                print "Emulator found! " + procname[:-1] + " Muting the music..."
                while volume > 0:
                    volume = volume - volumefadespeed
                    if volume < 0:
                        volume=0
                    mixer.music.set_volume(volume);
                    time.sleep(0.05)
                if restart:
                    mixer.music.stop()
                else:
                    mixer.music.pause() # TODO: Fadeout, rather than just outright stop.
                print("Muted.  Monitoring emulator.")
                while os.path.exists("/proc/" + pid):
                    time.sleep(1); # Delay 1 second and check again.
                #and here is where we'd turn it up.
                print "Emulator finished, resuming audio..."
                if not restart:
                    mixer.music.unpause() # TODO: Fadein, rather than just outright blare the audio.
                    while volume < maxvolume: # if restart is true, don't do anything - the volume resets when loading a song anyways.
                        volume = volume + volumefadespeed;
                        if volume > maxvolume:
                            volume=maxvolume
                        mixer.music.set_volume(volume);
                        time.sleep(0.05)
                #if restart is true, don't do anything - when the script restarts the main loop, it will force a re-test of the music and relaunch it.
                print "Restored."
                volume=maxvolume # if restart is true, fadeouts break after the first.  this prevents this.

        except IOError: #proc has already terminated, ignore.
            continue

    time.sleep(1);
    #end of the main while loop

print "An error has occurred that has stopped Test1.py from executing."