diff --git a/libavcodec/wmadec.c b/libavcodec/wmadec.c
index 47abcecc9c..d627bbe50e 100644
--- a/libavcodec/wmadec.c
+++ b/libavcodec/wmadec.c
@@ -988,7 +988,7 @@ const AVCodec ff_wmav1_decoder = {
     .capabilities   = AV_CODEC_CAP_DR1,
     .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
                                                       AV_SAMPLE_FMT_NONE },
-    .caps_internal  = FF_CODEC_CAP_INIT_CLEANUP,
+    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
 };
 #endif
 #if CONFIG_WMAV2_DECODER
@@ -1005,6 +1005,6 @@ const AVCodec ff_wmav2_decoder = {
     .capabilities   = AV_CODEC_CAP_DR1,
     .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
                                                       AV_SAMPLE_FMT_NONE },
-    .caps_internal  = FF_CODEC_CAP_INIT_CLEANUP,
+    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
 };
 #endif