doc: make libvlc_audio_set_volume_callback() dependency explicit

diff --git a/include/vlc/libvlc_media_player.h b/include/vlc/libvlc_media_player.h
index 9ba313e5d3a62a7e3d4992900bbd233704ed18a4..1c73cf2042ee7f8f6d5c377a37fc7ffd8fe55ef0 100644 (file)
--- a/include/vlc/libvlc_media_player.h
+++ b/include/vlc/libvlc_media_player.h
@@ -572,7 +572,8 @@ void libvlc_audio_set_callbacks( libvlc_media_player_t *mp,
                                  void *opaque );
 
 /**
- * Set callbacks and private data for decoded audio.
+ * Set callbacks and private data for decoded audio. This only works in
+ * combination with libvlc_audio_set_callbacks().
  * Use libvlc_audio_set_format() or libvlc_audio_set_format_callbacks()
  * to configure the decoded audio format.
  *