diff --git a/libavcodec/avdct.c b/libavcodec/avdct.c
index 47e5f7134e..7c761cf39a 100644
--- a/libavcodec/avdct.c
+++ b/libavcodec/avdct.c
@@ -100,7 +100,7 @@ int avcodec_dct_init(AVDCT *dsp)
 
 #if CONFIG_IDCTDSP
     {
-        IDCTDSPContext idsp;
+        IDCTDSPContext idsp = {0};
         ff_idctdsp_init(&idsp, avctx);
         COPY(idsp, idct);
         COPY(idsp, idct_permutation);