diff --git a/libavformat/rtp_asf.c b/libavformat/rtp_asf.c
index d44ff5a67f7d5467697ef11e0504ec72022f5eba..2b05b3e6d9aea08ad96151bb2d1ccf7c63fe7172 100644
--- a/libavformat/rtp_asf.c
+++ b/libavformat/rtp_asf.c
@@ -197,7 +197,7 @@ static int asfrtp_parse_packet(AVFormatContext *s, PayloadContext *asf,
             }
             if (!len_off && !asf->pktbuf &&
                 !(res = url_open_dyn_packet_buf(&asf->pktbuf, rt->asf_ctx->packet_size)))
-                return res;
+                return AVERROR(EIO);
             if (!asf->pktbuf)
                 return AVERROR(EIO);