--- libavformat/matroskadec.c.orig	2010-05-23 00:20:56.000000000 +0200
+++ libavformat/matroskadec.c	2010-05-23 01:04:04.000000000 +0200
@@ -828,7 +828,7 @@
 /*
  * Autodetecting...
  */
-static int matroska_probe(AVProbeData *p)
+static int ebml_probe(AVProbeData *p, const char probe_data[], const int probe_data_size)
 {
     uint64_t total = 0;
     int len_mask = 0x80, size = 1, n = 1, i;
@@ -868,6 +868,24 @@
     return AVPROBE_SCORE_MAX/2;
 }
 
+/*
+ * Autodetecting...
+ */
+#if CONFIG_MATROSKA_DEMUXER
+static int matroska_probe(AVProbeData *p)
+{
+    static const char probe_data[] = "matroska";
+    return ebml_probe(p, probe_data, sizeof(probe_data));
+}
+#endif
+#if CONFIG_WEBM_DEMUXER
+static int webm_probe(AVProbeData *p)
+{
+    static const char probe_data[] = "webm";
+    return ebml_probe(p, probe_data, sizeof(probe_data));
+}
+#endif
+
 static MatroskaTrack *matroska_find_track_by_num(MatroskaDemuxContext *matroska,
                                                  int num)
 {