diff --git a/lib/linux-x86_64/libao-play-async.so b/lib/linux-x86_64/libao-play-async.so
index f50f3ea..126ce84 100755
Binary files a/lib/linux-x86_64/libao-play-async.so and b/lib/linux-x86_64/libao-play-async.so differ
diff --git a/libao/c/ao-play-async/ao_playasync.c b/libao/c/ao-play-async/ao_playasync.c
index 54f2815..a3c8966 100644
--- a/libao/c/ao-play-async/ao_playasync.c
+++ b/libao/c/ao-play-async/ao_playasync.c
@@ -43,6 +43,7 @@ typedef struct _queue_ {
     void *buf;
     int buflen;
     double at_second;
+    double music_duration;
     struct _queue_ *next;
     struct _queue_ *prev;
 } Queue_t;
@@ -63,6 +64,7 @@ typedef struct {
     pthread_t       thread;
 #endif
     double          at_second;
+    double          music_duration;
     ao_play_func_t  ao_play_f;
     int             buf_size;
 } AO_Handle;
@@ -106,7 +108,7 @@ static void add(AO_Handle *h, Queue_t *elem)
     h->buf_size += elem->buflen;
 }
 
-static Queue_t *new_elem(int command, double at_second, int buf_len, void *buf)
+static Queue_t *new_elem(int command, double at_second, double music_duration, int buf_len, void *buf)
 {
     Queue_t *q = (Queue_t *) malloc(sizeof(Queue_t));
     void *new_buf;
@@ -118,6 +120,7 @@ static Queue_t *new_elem(int command, double at_second, int buf_len, void *buf)
         new_buf = NULL;
     }
     q->at_second = at_second;
+    q->music_duration = music_duration;
     q->buf = new_buf;
     q->buflen = buf_len;
     q->command = command;
@@ -220,7 +223,7 @@ void ao_stop_async(void *ao_handle)
 
     MUTEX_LOCK(h->mutex);
     clear(h);
-    Queue_t *q = new_elem(STOP, 0.0, 0, NULL);
+    Queue_t *q = new_elem(STOP, 0.0, 0.0, 0, NULL);
     add(h, q);
     MUTEX_UNLOCK(h->mutex);
 
@@ -236,10 +239,10 @@ void ao_stop_async(void *ao_handle)
     free(h);
 }
 
-void ao_play_async(void *ao_handle, double at_second, int buf_size, void *mem)
+void ao_play_async(void *ao_handle, double at_second, double music_duration, int buf_size, void *mem)
 {
     AO_Handle *h = (AO_Handle *) ao_handle;
-    Queue_t *q = new_elem(PLAY, at_second, buf_size, mem);
+    Queue_t *q = new_elem(PLAY, at_second, music_duration, buf_size, mem);
     MUTEX_LOCK(h->mutex);
     add(h, q);
     MUTEX_UNLOCK(h->mutex);
@@ -262,6 +265,16 @@ double ao_is_at_second_async(void *ao_handle)
     return s;
 }
 
+
+double ao_music_duration_async(void *ao_handle)
+{
+    AO_Handle *h = (AO_Handle *) ao_handle;
+    MUTEX_LOCK(h->mutex);
+    double duration = h->at_second;
+    MUTEX_UNLOCK(h->mutex);
+    return duration;
+}
+
 int ao_bufsize_async(void *ao_handle)
 {
     AO_Handle *h = (AO_Handle *) ao_handle;
diff --git a/libao/c/ao-play-async/ao_playasync.h b/libao/c/ao-play-async/ao_playasync.h
index 696bfa1..287f7d0 100644
--- a/libao/c/ao-play-async/ao_playasync.h
+++ b/libao/c/ao-play-async/ao_playasync.h
@@ -13,9 +13,12 @@
 
 AOPLAYASYNC_EXPORT void *ao_create_async(void *ao_handle, void *ao_play_f);
 AOPLAYASYNC_EXPORT void ao_stop_async(void *handle);
-AOPLAYASYNC_EXPORT void ao_play_async(void *handle, double at_second, int buf_size, void *mem);
+AOPLAYASYNC_EXPORT void ao_play_async(void *handle, double at_second, double music_duration, int buf_size, void *mem);
 AOPLAYASYNC_EXPORT void ao_clear_async(void *handle);
+
 AOPLAYASYNC_EXPORT double ao_is_at_second_async(void *handle);
+AOPLAYASYNC_EXPORT double ao_music_duration_async(void *handle);
+
 AOPLAYASYNC_EXPORT int ao_bufsize_async(void *handle);
 
 #endif // AO_PLAYASYNC_H
diff --git a/libao/libao-async-ffi.rkt b/libao/libao-async-ffi.rkt
index 3882956..a0ca304 100644
--- a/libao/libao-async-ffi.rkt
+++ b/libao/libao-async-ffi.rkt
@@ -32,6 +32,8 @@
 ;extern double ao_is_at_second_async(void *handle);
 (define-libao-async ao_is_at_second_async(_fun _libao-async-handle-pointer -> _double))
 
+
+
 ;extern int ao_bufsize_async(void *handle);
 (define-libao-async ao_bufsize_async(_fun _libao-async-handle-pointer -> _int))