diff --git a/libavcodec/ffwavesynth.c b/libavcodec/ffwavesynth.c
index c99bac90ea..7e7e1f6954 100644
--- a/libavcodec/ffwavesynth.c
+++ b/libavcodec/ffwavesynth.c
@@ -469,5 +469,5 @@ AVCodec ff_ffwavesynth_decoder = {
     .close          = wavesynth_close,
     .decode         = wavesynth_decode,
     .capabilities   = AV_CODEC_CAP_DR1,
-    .caps_internal  = FF_CODEC_CAP_INIT_CLEANUP,
+    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
 };