diff --git a/libavcodec/avdct.c b/libavcodec/avdct.c
index 80aca8872b..7853f7a226 100644
--- a/libavcodec/avdct.c
+++ b/libavcodec/avdct.c
@@ -109,7 +109,7 @@ 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);