diff --git a/gst-libs/gst/audio/gstaudiodecoder.c b/gst-libs/gst/audio/gstaudiodecoder.c
index 7f086fef91..c3acb2e0bb 100644
--- a/gst-libs/gst/audio/gstaudiodecoder.c
+++ b/gst-libs/gst/audio/gstaudiodecoder.c
@@ -1842,6 +1842,7 @@ gst_audio_decoder_negotiate_default_caps (GstAudioDecoder * dec)
     goto caps_error;
 
   /* before fixating, try to use whatever upstream provided */
+  caps = gst_caps_make_writable (caps);
   caps_size = gst_caps_get_size (caps);
   if (dec->priv->ctx.input_caps) {
     GstCaps *sinkcaps = dec->priv->ctx.input_caps;