Fix audio overhead

Index: libogmrip/ogmrip-container.c
===================================================================
--- libogmrip/ogmrip-container.c	(révision 843)
+++ libogmrip/ogmrip-container.c	(copie de travail)
@@ -563,12 +563,15 @@
 ogmrip_container_get_audio_overhead (OGMRipContainer *container, OGMRipContainerChild *child)
 {
   glong length;
-  gint samples_per_frame, bitrate = 0;
+  gint samples_per_frame, sample_rate;
+  guint numerator, denominator;
 
   length = ogmrip_codec_get_length (child->codec, NULL);
+  sample_rate = ogmrip_audio_get_sample_rate (OGMRIP_AUDIO (child->codec));
   samples_per_frame = ogmrip_audio_get_samples_per_frame (OGMRIP_AUDIO (child->codec));
+  ogmrip_codec_get_framerate (OGMRIP_CODEC (child->codec), &numerator, &denominator);
 
-  return (gint64) length * bitrate * container->priv->overhead / (gdouble) samples_per_frame;
+  return (gint64) length * sample_rate * denominator * container->priv->overhead / (gdouble) (samples_per_frame * numerator);
 }
 
 static gint64
