volume: Explicitly cast integers to doubles and then back to integers after multiplic...

gcc 4.9.1 on ARM seems to have a bug that causes it to cast the float to an
integer first, resulting in a 0 scale factor for volume < 1.0.

As a side effect this change here will also improve accuracy of the result a
bit because we go via doubles instead of floats.

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65325
https://bugzilla.gnome.org/show_bug.cgi?id=745667

diff --git a/gst/volume/gstvolume.c b/gst/volume/gstvolume.c
index 0f5b362..94d03a3 100644 (file)
--- a/gst/volume/gstvolume.c
+++ b/gst/volume/gstvolume.c
@@ -250,10 +250,14 @@ volume_update_volume (GstVolume * self, const GstAudioInfo * info,
     self->current_mute = FALSE;
     self->current_volume = volume;
 
-    self->current_vol_i8 = volume * VOLUME_UNITY_INT8;
-    self->current_vol_i16 = volume * VOLUME_UNITY_INT16;
-    self->current_vol_i24 = volume * VOLUME_UNITY_INT24;
-    self->current_vol_i32 = volume * VOLUME_UNITY_INT32;
+    self->current_vol_i8 =
+        (gint) ((gdouble) volume * (gdouble) VOLUME_UNITY_INT8);
+    self->current_vol_i16 =
+        (gint) ((gdouble) volume * (gdouble) VOLUME_UNITY_INT16);
+    self->current_vol_i24 =
+        (gint) ((gdouble) volume * (gdouble) VOLUME_UNITY_INT24);
+    self->current_vol_i32 =
+        (gint) ((gdouble) volume * (gdouble) VOLUME_UNITY_INT32);
 
     passthrough = (self->current_vol_i16 == VOLUME_UNITY_INT16);
   }