input: create an aout if UI wants to configure audio (fixes #7810)

src/input/resource.c

@@ -387,6 +387,11 @@ audio_output_t *input_resource_HoldAout( input_resource_t *p_resource )
 
     vlc_mutex_lock( &p_resource->lock_hold );
     p_aout = p_resource->p_aout;
+    if( p_aout == NULL )
+    {   /* No audio outputs exist yet. Create an idle one. */
+        p_aout = aout_New( p_resource->p_parent );
+        p_resource->p_aout = p_aout;
+    }
     if( p_aout )
         vlc_object_hold( p_aout );
     vlc_mutex_unlock( &p_resource->lock_hold );

src/playlist/aout.c

@@ -33,10 +33,6 @@
 
 audio_output_t *playlist_GetAout(playlist_t *pl)
 {
-    /* NOTE: it is assumed that the input resource exists. In practice,
-     * the playlist must have been activated. This is automatic when calling
-     * pl_Get(). FIXME: input resources are deleted at deactivation, this can
-     * be too early. */
     playlist_private_t *sys = pl_priv(pl);
     return input_resource_HoldAout(sys->p_input_resource);
 }