diff --git a/libavcodec/on2avc.c b/libavcodec/on2avc.c
index 2ab67350ca..fa3eb4b219 100644
--- a/libavcodec/on2avc.c
+++ b/libavcodec/on2avc.c
@@ -1012,7 +1012,7 @@ const AVCodec ff_on2avc_decoder = {
     .decode         = on2avc_decode_frame,
     .close          = on2avc_decode_close,
     .capabilities   = AV_CODEC_CAP_DR1,
-    .caps_internal  = FF_CODEC_CAP_INIT_CLEANUP,
+    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
     .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
                                                       AV_SAMPLE_FMT_NONE },
 };