diff --git a/vpxdec.c b/vpxdec.c
index faee42a0ba2c8d73466188af44d4e77bb3bccf0e..1b4872da39d4bad65b6eb8137914774e06c7dcc7 100644
--- a/vpxdec.c
+++ b/vpxdec.c
@@ -538,7 +538,8 @@ int main_loop(int argc, const char **argv_) {
   struct VpxDecInputContext input = {NULL, NULL};
   struct VpxInputContext vpx_input_ctx;
 #if CONFIG_WEBM_IO
-  struct WebmInputContext webm_ctx = {0};
+  struct WebmInputContext webm_ctx;
+  memset(&(webm_ctx), 0, sizeof(webm_ctx));
   input.webm_ctx = &webm_ctx;
 #endif
   input.vpx_input_ctx = &vpx_input_ctx;