diff --git a/src/dec/idec.c b/src/dec/idec.c
index f2e64ad4..b4d705aa 100644
--- a/src/dec/idec.c
+++ b/src/dec/idec.c
@@ -619,11 +619,11 @@ void WebPIDelete(WebPIDecoder* idec) {
     if (!idec->is_lossless_) {
       if (idec->state_ == STATE_VP8_DATA) {
         // Synchronize the thread, clean-up and check for errors.
-        VP8ExitCritical(idec->dec_, &idec->io_);
+        VP8ExitCritical((VP8Decoder*)idec->dec_, &idec->io_);
       }
-      VP8Delete(idec->dec_);
+      VP8Delete((VP8Decoder*)idec->dec_);
     } else {
-      VP8LDelete(idec->dec_);
+      VP8LDelete((VP8LDecoder*)idec->dec_);
     }
   }
   ClearMemBuffer(&idec->mem_);