diff --git a/libavcodec/flacdec.c b/libavcodec/flacdec.c
index c62661a353..09051cc663 100644
--- a/libavcodec/flacdec.c
+++ b/libavcodec/flacdec.c
@@ -678,4 +678,5 @@ const AVCodec ff_flac_decoder = {
                                                       AV_SAMPLE_FMT_S32P,
                                                       AV_SAMPLE_FMT_NONE },
     .priv_class     = &flac_decoder_class,
+    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
 };