-#ifdef SYS_DARWIN
-# define VLC_THREAD_PRIORITY_LOW 1
-# define VLC_THREAD_PRIORITY_INPUT 1
-# define VLC_THREAD_PRIORITY_AUDIO 1
-# define VLC_THREAD_PRIORITY_VIDEO 1
-# define VLC_THREAD_PRIORITY_OUTPUT 1
+#ifdef __APPLE__
+# define VLC_THREAD_PRIORITY_LOW (-47)
+# define VLC_THREAD_PRIORITY_INPUT 37
+# define VLC_THREAD_PRIORITY_AUDIO 37
+# define VLC_THREAD_PRIORITY_VIDEO (-47)
+# define VLC_THREAD_PRIORITY_OUTPUT 37
+# define VLC_THREAD_PRIORITY_HIGHEST 37
+
+#elif defined(SYS_BEOS)
+# define VLC_THREAD_PRIORITY_LOW 5
+# define VLC_THREAD_PRIORITY_INPUT 10
+# define VLC_THREAD_PRIORITY_AUDIO 10
+# define VLC_THREAD_PRIORITY_VIDEO 5
+# define VLC_THREAD_PRIORITY_OUTPUT 15
+# define VLC_THREAD_PRIORITY_HIGHEST 15
+
+#elif defined(PTHREAD_COND_T_IN_PTHREAD_H)
+# define VLC_THREAD_PRIORITY_LOW 0
+# define VLC_THREAD_PRIORITY_INPUT 20
+# define VLC_THREAD_PRIORITY_AUDIO 10
+# define VLC_THREAD_PRIORITY_VIDEO 0
+# define VLC_THREAD_PRIORITY_OUTPUT 30
+# define VLC_THREAD_PRIORITY_HIGHEST 40