diff --git a/libavformat/mmst.c b/libavformat/mmst.c
index 93ad073869..4b96f5d6af 100644
--- a/libavformat/mmst.c
+++ b/libavformat/mmst.c
@@ -144,7 +144,7 @@ static int send_command_packet(MMSTContext *mmst)
         av_log(NULL, AV_LOG_ERROR,
                "Failed to write data of length %d: %d (%s)\n",
                exact_length, write_result,
-               write_result < 0 ? strerror(write_result) :
+               write_result < 0 ? strerror(AVUNERROR(write_result)) :
                    "The server closed the connection");
         return AVERROR(EIO);
     }
@@ -246,7 +246,7 @@ static MMSSCPacketType get_tcp_server_response(MMSTContext *mmst)
             if(read_result < 0) {
                 av_log(NULL, AV_LOG_ERROR,
                        "Error reading packet header: %d (%s)\n",
-                       read_result, strerror(read_result));
+                       read_result, strerror(AVUNERROR(read_result)));
                 packet_type = SC_PKT_CANCEL;
             } else {
                 av_log(NULL, AV_LOG_ERROR,
@@ -266,7 +266,7 @@ static MMSSCPacketType get_tcp_server_response(MMSTContext *mmst)
                 av_log(NULL, AV_LOG_ERROR,
                        "Reading command packet length failed: %d (%s)\n",
                        read_result,
-                       read_result < 0 ? strerror(read_result) :
+                       read_result < 0 ? strerror(AVUNERROR(read_result)) :
                            "The server closed the connection");
                 return read_result < 0 ? read_result : AVERROR(EIO);
             }
@@ -287,7 +287,7 @@ static MMSSCPacketType get_tcp_server_response(MMSTContext *mmst)
                 av_log(NULL, AV_LOG_ERROR,
                        "Reading pkt data (length=%d) failed: %d (%s)\n",
                        length_remaining, read_result,
-                       read_result < 0 ? strerror(read_result) :
+                       read_result < 0 ? strerror(AVUNERROR(read_result)) :
                            "The server closed the connection");
                 return read_result < 0 ? read_result : AVERROR(EIO);
             }
@@ -324,7 +324,7 @@ static MMSSCPacketType get_tcp_server_response(MMSTContext *mmst)
                 av_log(NULL, AV_LOG_ERROR,
                        "Failed to read packet data of size %d: %d (%s)\n",
                        length_remaining, read_result,
-                       read_result < 0 ? strerror(read_result) :
+                       read_result < 0 ? strerror(AVUNERROR(read_result)) :
                            "The server closed the connection");
                 return read_result < 0 ? read_result : AVERROR(EIO);
             }