libvlc/control: make sure aout is active before attempting to use channels

src/control/audio.c

@@ -217,11 +217,15 @@ int libvlc_audio_get_channel( libvlc_instance_t *p_instance,
                                 libvlc_exception_t *p_e )
 {
     aout_instance_t *p_aout = GetAOut( p_instance, p_e );
+    if( p_aout )
+    {
         vlc_value_t val;
 
         var_Get( p_aout, "audio-channels", &val );
         vlc_object_release( p_aout );
         return val.i_int;
+    }
+    return -1;
 }
 
 /*****************************************************************************
@@ -231,6 +235,8 @@ void libvlc_audio_set_channel( libvlc_instance_t *p_instance, int i_channel,
                                libvlc_exception_t *p_e )
 {
     aout_instance_t *p_aout = GetAOut( p_instance, p_e );
+    if( p_aout )
+    {
         vlc_value_t val;
         int i_ret = -1;
 
@@ -256,4 +262,5 @@ void libvlc_audio_set_channel( libvlc_instance_t *p_instance, int i_channel,
                 break;
         }
         vlc_object_release( p_aout );
+    }
 }