diff --git a/libavcodec/mpegaudioenc_fixed.c b/libavcodec/mpegaudioenc_fixed.c
index 1504834925..ce8963fd0b 100644
--- a/libavcodec/mpegaudioenc_fixed.c
+++ b/libavcodec/mpegaudioenc_fixed.c
@@ -38,4 +38,5 @@ const AVCodec ff_mp2fixed_encoder = {
                                                  AV_CH_LAYOUT_STEREO,
                                                  0 },
     .defaults              = mp2_defaults,
+    .caps_internal         = FF_CODEC_CAP_INIT_THREADSAFE,
 };
diff --git a/libavcodec/mpegaudioenc_float.c b/libavcodec/mpegaudioenc_float.c
index 22c5f916b2..ba3b096579 100644
--- a/libavcodec/mpegaudioenc_float.c
+++ b/libavcodec/mpegaudioenc_float.c
@@ -39,4 +39,5 @@ const AVCodec ff_mp2_encoder = {
                                                  AV_CH_LAYOUT_STEREO,
                                                  0 },
     .defaults              = mp2_defaults,
+    .caps_internal         = FF_CODEC_CAP_INIT_THREADSAFE,
 };