diff --git a/libavcodec/libx264.c b/libavcodec/libx264.c
index 8614ec5cd3..bff29d892c 100644
--- a/libavcodec/libx264.c
+++ b/libavcodec/libx264.c
@@ -476,6 +476,7 @@ static const AVClass class = {
 
 static const AVCodecDefault x264_defaults[] = {
     { "b",                "0" },
+    { "threads",          "0" },
     { NULL },
 };