diff --git a/pgfw/Audio.py b/pgfw/Audio.py
index 7cb1dd0..9905ec1 100644
--- a/pgfw/Audio.py
+++ b/pgfw/Audio.py
@@ -11,16 +11,16 @@ from .extension import *
 class Audio(Animation):
 
     UP, DOWN = .1, -.1
-    BASE_VOLUME = 1.0
     CONFIG_SEPARATOR = ","
 
     def __init__(self, game):
         Animation.__init__(self, game)
         # self.original_volumes = {}
         self.current_bgm = None
-        self.volume = self.BASE_VOLUME
+        self.volume = 1.0
+        self.pre_muted_volume = None
         if self.check_command_line("-mute"):
-            self.volume = 0
+            self.get_configuration().set("audio", "volume", 0)
         self.register(self.play_sfx)
         self.audio_panel = AudioPanel(self)
         self.subscribe(self.respond)
@@ -28,19 +28,34 @@ class Audio(Animation):
         self.load_sfx()
         self.bgm = {}
         self.load_bgm()
+        self.set_volume(self.get_configuration("audio", "volume"))
 
-    def set_volume(self, volume=None, increment=None, mute=False):
+    def set_volume(self, volume=None, increment=None, mute=False, unmute=False):
         if mute:
+            self.pre_muted_volume = self.volume
             self.volume = 0
+        elif unmute and self.pre_muted_volume is not None:
+            self.volume = self.pre_muted_volume
+            self.pre_muted_volume = None
         elif increment:
             self.volume = clamp(self.volume + increment, 0, 1.0)
         else:
             self.volume = volume
+        self.get_configuration().set("audio", "volume", self.volume)
+        if pygame.mixer.music.get_busy():
+            pygame.mixer.music.set_volume(self.current_bgm.volume * self.volume)
+        for ii in range(pygame.mixer.get_num_channels()):
+            channel = pygame.mixer.Channel(ii)
+            if channel.get_busy():
+                channel.set_volume(channel.get_sound().get_volume() * self.volume)
 
     def respond(self, event):
         compare = self.get_game().delegate.compare
         if compare(event, "volume-mute"):
-            self.set_volume(mute=True)
+            if self.volume > 0:
+                self.set_volume(mute=True)
+            else:
+                self.set_volume(unmute=True)
         elif compare(event, "volume-up"):
             self.set_volume(increment=self.UP)
         elif compare(event, "volume-down"):
@@ -163,7 +178,7 @@ class Audio(Animation):
             pygame.mixer.music.play(-1, start)
         except pygame.error:
             pygame.mixer.music.play(-1)
-        pygame.mixer.music.set_volume(bgm.get_volume())
+        pygame.mixer.music.set_volume(bgm.get_volume() * self.get_configuration("audio", "volume"))
         if store_as_current:
             self.current_bgm = bgm
 
@@ -229,7 +244,7 @@ class SoundEffect(GameChild, pygame.mixer.Sound):
     def play(self, loops=None, maxtime=None, fade_ms=None, position=None,
              x=None):
         self.set_volume(
-            self.local_volume * self.get_configuration("audio", "sfx-volume"))
+            self.local_volume * self.get_configuration("audio", "volume"))
         if loops is None:
             loops = self.loops
         if maxtime is None:
diff --git a/pgfw/Configuration.py b/pgfw/Configuration.py
index 610e69c..5381280 100644
--- a/pgfw/Configuration.py
+++ b/pgfw/Configuration.py
@@ -150,6 +150,8 @@ class Configuration(RawConfigParser):
         set_option(section, "bgm-repository-path", "~/storage/audio/bgm", False)
         set_option(section, "bgm-project-path", "bgm", False)
         set_option(section, "sfx-volume", "1.0", False)
+        set_option(section, "bgm-volume", "1.0", False)
+        set_option(section, "volume", "1.0", False)
         set_option(section, "panel-font", None, False)
         section = "interpolator-gui"
         add_section(section)
@@ -450,7 +452,7 @@ class TypeDeclarations(dict):
                 "bgm-repository-path", "bgm-project-path"
             ],
 
-            "float": "sfx-volume"
+            "float": ["sfx-volume", "bgm-volume", "volume"]
         },
 
         "event": {"int": "command-id-offset"},
diff --git a/pgfw/extension.py b/pgfw/extension.py
index 370cc08..8e13027 100644
--- a/pgfw/extension.py
+++ b/pgfw/extension.py
@@ -125,9 +125,11 @@ def constrain_dimensions_2d(vector, container):
     dh = vector[1] - container[1]
     if dw > 0 or dh > 0:
         if dw > dh:
-            size = container[0], int(round(container[0] / vector[0] * vector[1]))
+            size = Vector(container[0], int(round(container[0] / vector[0] * vector[1])))
         else:
-            size = int(round(container[1] / vector[1] * vector[0])), container[1]
+            size = Vector(int(round(container[1] / vector[1] * vector[0])), container[1])
+    else:
+        size = Vector(vector[0], vector[1])
     return size
 
 # from http://www.realtimerendering.com/resources/GraphicsGems/gemsii/xlines.c