diff --git a/libavdevice/dshow.c b/libavdevice/dshow.c
index 57d8e1c0af..84db151577 100644
--- a/libavdevice/dshow.c
+++ b/libavdevice/dshow.c
@@ -898,8 +898,8 @@ dshow_cycle_formats(AVFormatContext *avctx, enum dshowDeviceType devtype,
 
         if (devtype == VideoDevice) {
             VIDEO_STREAM_CONFIG_CAPS *vcaps = caps;
-            BITMAPINFOHEADER *bih;
-            int64_t *fr;
+            BITMAPINFOHEADER *bih = NULL;
+            int64_t *fr = NULL;
 #if DSHOWDEBUG
             ff_print_VIDEO_STREAM_CONFIG_CAPS(vcaps);
 #endif