Change the default hotkeys to avoid conflicts.

1) Every Human Interface Guideline on Unix/Linux/Windows reserves alt key for menu and button accessibility... Try to NOT use those...
Moreover, you have NO idea how the translators are going to translate your accelerators...

On the other hand, with this long list of keys it was become more than difficult... I'll document on the wiki.

2) Use keys next-to-each-other like-a-cross for cropping

Those keys are making a cross in most layouts ( on the contrary to the previous ones).

3) At the same time, use easier snapshot key. (shift+s is easier than Ctrl+alt+s)

4) Comment previous changes and remove whitespace.

Nota Bene:
I have no idea on how are the default on the mac and if the are conflicts there too, so I won't make changes there.
(cherry picked from commit d6ff5d2c31d8da17c97e1af89fbabde5c80cbe88)

src/libvlc-module.c

@@ -2130,7 +2130,7 @@ vlc_module_begin();
 #   define KEY_UNCROP_RIGHT       KEY_MODIFIER_ALT|KEY_MODIFIER_SHIFT|'l'
 
 /* the macosx-interface already has bindings */
-#   define KEY_ZOOM_QUARTER       KEY_UNSET 
+#   define KEY_ZOOM_QUARTER       KEY_UNSET
 #   define KEY_ZOOM_HALF          KEY_UNSET
 #   define KEY_ZOOM_ORIGINAL      KEY_UNSET
 #   define KEY_ZOOM_DOUBLE        KEY_UNSET
@@ -2169,7 +2169,14 @@ vlc_module_begin();
 #   define KEY_MENU_DOWN          KEY_MODIFIER_ALT|KEY_MODIFIER_SHIFT|KEY_DOWN
 #   define KEY_MENU_SELECT        KEY_MODIFIER_ALT|KEY_MODIFIER_SHIFT|KEY_ENTER
 
-#else
+#else /* Non Mac OS X */
+    /*
+       You should try to avoid Ctrl + letter key, because they are usually for
+       dialogs showing and interface related stuffs.
+       It would be nice (less important than previous rule) to try to avoid
+       alt + letter key, because they are usually for menu accelerators and you
+       don't know how the translator is going to do it.
+     */
 #   define KEY_TOGGLE_FULLSCREEN  'f'
 #   define KEY_LEAVE_FULLSCREEN   KEY_ESC
 #   define KEY_PLAY_PAUSE         KEY_SPACE
@@ -2212,30 +2219,41 @@ vlc_module_begin();
 #   define KEY_DEINTERLACE        'd'
 #   define KEY_INTF_SHOW          'i'
 #   define KEY_INTF_HIDE          KEY_MODIFIER_SHIFT|'i'
-#   define KEY_DISC_MENU          KEY_MODIFIER_ALT|'r'
-#   define KEY_TITLE_PREV         KEY_MODIFIER_ALT|'o'
-#   define KEY_TITLE_NEXT         KEY_MODIFIER_ALT|'b'
-#   define KEY_CHAPTER_PREV       KEY_MODIFIER_ALT|'p'
-#   define KEY_CHAPTER_NEXT       KEY_MODIFIER_ALT|'n'
-#   define KEY_SNAPSHOT           KEY_MODIFIER_CTRL|KEY_MODIFIER_ALT|'s'
+#   define KEY_DISC_MENU          KEY_MODIFIER_SHIFT|'m'
+#   define KEY_TITLE_PREV         KEY_MODIFIER_SHIFT|'o'
+#   define KEY_TITLE_NEXT         KEY_MODIFIER_SHIFT|'b'
+#   define KEY_CHAPTER_PREV       KEY_MODIFIER_SHIFT|'p'
+#   define KEY_CHAPTER_NEXT       KEY_MODIFIER_SHIFT|'n'
+#   define KEY_SNAPSHOT           KEY_MODIFIER_SHIFT|'s'
 
 #   define KEY_ZOOM               'z'
 #   define KEY_UNZOOM             KEY_MODIFIER_SHIFT|'z'
 
-#   define KEY_CROP_TOP           KEY_MODIFIER_ALT|'i'
-#   define KEY_UNCROP_TOP         KEY_MODIFIER_ALT|KEY_MODIFIER_SHIFT|'i'
-#   define KEY_CROP_LEFT          KEY_MODIFIER_ALT|'j'
-#   define KEY_UNCROP_LEFT        KEY_MODIFIER_ALT|KEY_MODIFIER_SHIFT|'j'
-#   define KEY_CROP_BOTTOM        KEY_MODIFIER_ALT|'k'
-#   define KEY_UNCROP_BOTTOM      KEY_MODIFIER_ALT|KEY_MODIFIER_SHIFT|'k'
-#   define KEY_CROP_RIGHT         KEY_MODIFIER_ALT|'l'
-#   define KEY_UNCROP_RIGHT       KEY_MODIFIER_ALT|KEY_MODIFIER_SHIFT|'l'
+#   define KEY_AUDIODEVICE_CYCLE  KEY_MODIFIER_SHIFT|'a'
+
+#   define KEY_HISTORY_BACK       KEY_MODIFIER_SHIFT|'g'
+#   define KEY_HISTORY_FORWARD    KEY_MODIFIER_SHIFT|'h'
+#   define KEY_RECORD             KEY_MODIFIER_SHIFT|'r'
+#   define KEY_DUMP               KEY_MODIFIER_SHIFT|'d'
+#   define KEY_WALLPAPER          'w'
 
+/* Cropping */
+#   define KEY_CROP_TOP           KEY_MODIFIER_ALT|'r'
+#   define KEY_UNCROP_TOP         KEY_MODIFIER_ALT|KEY_MODIFIER_SHIFT|'r'
+#   define KEY_CROP_LEFT          KEY_MODIFIER_ALT|'d'
+#   define KEY_UNCROP_LEFT        KEY_MODIFIER_ALT|KEY_MODIFIER_SHIFT|'d'
+#   define KEY_CROP_BOTTOM        KEY_MODIFIER_ALT|'c'
+#   define KEY_UNCROP_BOTTOM      KEY_MODIFIER_ALT|KEY_MODIFIER_SHIFT|'c'
+#   define KEY_CROP_RIGHT         KEY_MODIFIER_ALT|'f'
+#   define KEY_UNCROP_RIGHT       KEY_MODIFIER_ALT|KEY_MODIFIER_SHIFT|'f'
+
+/* Zooming */
 #   define KEY_ZOOM_QUARTER       KEY_MODIFIER_CTRL|'1'
 #   define KEY_ZOOM_HALF          KEY_MODIFIER_CTRL|'2'
 #   define KEY_ZOOM_ORIGINAL      KEY_MODIFIER_CTRL|'3'
 #   define KEY_ZOOM_DOUBLE        KEY_MODIFIER_CTRL|'4'
 
+/* Bookmarks */
 #   define KEY_SET_BOOKMARK1      KEY_MODIFIER_CTRL|KEY_F1
 #   define KEY_SET_BOOKMARK2      KEY_MODIFIER_CTRL|KEY_F2
 #   define KEY_SET_BOOKMARK3      KEY_MODIFIER_CTRL|KEY_F3
@@ -2256,20 +2274,15 @@ vlc_module_begin();
 #   define KEY_PLAY_BOOKMARK8     KEY_F8
 #   define KEY_PLAY_BOOKMARK9     KEY_F9
 #   define KEY_PLAY_BOOKMARK10    KEY_F10
-#   define KEY_HISTORY_BACK       KEY_MODIFIER_ALT|'g'
-#   define KEY_HISTORY_FORWARD    KEY_MODIFIER_ALT|'h'
-#   define KEY_RECORD             KEY_MODIFIER_CTRL|KEY_MODIFIER_SHIFT|'r'
-#   define KEY_DUMP               KEY_MODIFIER_CTRL|KEY_MODIFIER_SHIFT|'d'
-#   define KEY_WALLPAPER          'w'
 
-#   define KEY_MENU_ON            KEY_MODIFIER_ALT|'m'
-#   define KEY_MENU_OFF           KEY_MODIFIER_ALT|KEY_MODIFIER_SHIFT|'m'
+/* OSD menu */
+#   define KEY_MENU_ON            KEY_MODIFIER_ALT|KEY_MODIFIER_SHIFT|'m'
+#   define KEY_MENU_OFF           KEY_MODIFIER_ALT|KEY_MODIFIER_CTRL|'m'
 #   define KEY_MENU_RIGHT         KEY_MODIFIER_ALT|KEY_MODIFIER_SHIFT|KEY_RIGHT
 #   define KEY_MENU_LEFT          KEY_MODIFIER_ALT|KEY_MODIFIER_SHIFT|KEY_LEFT
 #   define KEY_MENU_UP            KEY_MODIFIER_ALT|KEY_MODIFIER_SHIFT|KEY_UP
 #   define KEY_MENU_DOWN          KEY_MODIFIER_ALT|KEY_MODIFIER_SHIFT|KEY_DOWN
 #   define KEY_MENU_SELECT        KEY_MODIFIER_ALT|KEY_MODIFIER_SHIFT|KEY_ENTER
-#   define KEY_AUDIODEVICE_CYCLE  KEY_MODIFIER_ALT|'a'
 #endif
 
     add_key( "key-toggle-fullscreen", KEY_TOGGLE_FULLSCREEN, NULL, TOGGLE_FULLSCREEN_KEY_TEXT,
@@ -2418,15 +2431,15 @@ vlc_module_begin();
              LOOP_KEY_TEXT, LOOP_KEY_LONGTEXT, false );
 
     set_section ( N_("Zoom" ), NULL );
-    add_key( "key-zoom-quarter",  KEY_ZOOM_QUARTER, NULL, 
+    add_key( "key-zoom-quarter",  KEY_ZOOM_QUARTER, NULL,
         ZOOM_QUARTER_KEY_TEXT,  NULL, false );
-    add_key( "key-zoom-half",     KEY_ZOOM_HALF, NULL, 
+    add_key( "key-zoom-half",     KEY_ZOOM_HALF, NULL,
         ZOOM_HALF_KEY_TEXT,     NULL, false );
-    add_key( "key-zoom-original", KEY_ZOOM_ORIGINAL, NULL, 
+    add_key( "key-zoom-original", KEY_ZOOM_ORIGINAL, NULL,
         ZOOM_ORIGINAL_KEY_TEXT, NULL, false );
-    add_key( "key-zoom-double",   KEY_ZOOM_DOUBLE, NULL, 
+    add_key( "key-zoom-double",   KEY_ZOOM_DOUBLE, NULL,
         ZOOM_DOUBLE_KEY_TEXT,   NULL, false );
-    
+
     set_section ( N_("Jump sizes" ), NULL );
     add_integer( "extrashort-jump-size", 3, NULL, JIEXTRASHORT_TEXT,
                                     JIEXTRASHORT_LONGTEXT, false );
@@ -2533,7 +2546,7 @@ vlc_module_begin();
     N_("resets the current plugins cache")
 #define VERSION_TEXT \
     N_("print version information")
- 
+
     add_bool( "help", false, NULL, HELP_TEXT, "", false );
         change_short( 'h' );
         change_internal();