diff --git a/src/liboggz/oggz.c b/src/liboggz/oggz.c
index ad33217a5505ca07fc43059e084600a76f960351..b983391d37db018d2e583977ebace1122c46413f 100644
--- a/src/liboggz/oggz.c
+++ b/src/liboggz/oggz.c
@@ -449,6 +449,24 @@ oggz_set_metric_linear (OGGZ * oggz, long serialno,
 				   linear_data, 1);
 }
 
+/*
+ * Check if a stream in an oggz has a metric
+ */
+int
+oggz_stream_has_metric (OGGZ * oggz, long serialno)
+{
+  oggz_stream_t * stream;
+
+  if (oggz->metric != NULL) return 1;
+
+  stream = oggz_get_stream (oggz, serialno);
+  if (stream == NULL) return OGGZ_ERR_BAD_SERIALNO;
+
+  if (stream->metric != NULL) return 1;
+
+  return 0;
+}
+
 /*
  * Check if an oggz has metrics for all streams
  */
diff --git a/src/liboggz/oggz_auto.c b/src/liboggz/oggz_auto.c
index aff898e84b081fafd632046de65b2c825e4c901a..18c97251c3ec3f87be9a66245e0fa4011009a600 100644
--- a/src/liboggz/oggz_auto.c
+++ b/src/liboggz/oggz_auto.c
@@ -42,10 +42,11 @@
 #include <stdlib.h>
 #include <string.h>
 
-#include "oggz_private.h"
+#include <oggz/oggz.h>
 #include "oggz_auto.h"
 #include "oggz_byteorder.h"
 #include "oggz_macros.h"
+#include "oggz_stream.h"
 
 /* Allow use of internal metrics; ie. the user_data for these gets free'd
  * when the metric is overwritten, or on close */
@@ -299,7 +300,6 @@ auto_fisbone (OGGZ * oggz, ogg_packet * op, long serialno, void * user_data)
 {
   unsigned char * header = op->packet;
   long fisbone_serialno; /* The serialno referred to in this fisbone */
-  oggz_stream_t * fisbone_stream; /* The stream of that serialno */
   ogg_int64_t granule_rate_numerator = 0, granule_rate_denominator = 0;
 
   if (op->bytes < 48) return 0;
@@ -307,10 +307,9 @@ auto_fisbone (OGGZ * oggz, ogg_packet * op, long serialno, void * user_data)
   if (strncmp ((char *)header, "fisbone", 7)) return 0;
 
   fisbone_serialno = (long) INT32_LE_AT(&header[12]);
-  fisbone_stream = oggz_get_stream (oggz, fisbone_serialno);
 
   /* Don't override an already assigned metric */
-  if (fisbone_stream->metric) return 1;
+  if (oggz_stream_has_metric (oggz, fisbone_serialno)) return 1;
 
   granule_rate_numerator = INT64_LE_AT(&header[20]);
   granule_rate_denominator = INT64_LE_AT(&header[28]);
diff --git a/src/liboggz/oggz_private.h b/src/liboggz/oggz_private.h
index c3cf39d9adf066b9137cb0c694d55ebf00b77f79..ff4c9bbe55abcb45e7722a93936ad8a558292fe9 100644
--- a/src/liboggz/oggz_private.h
+++ b/src/liboggz/oggz_private.h
@@ -47,6 +47,9 @@ typedef struct _OggzIO OggzIO;
 typedef struct _OggzReader OggzReader;
 typedef struct _OggzWriter OggzWriter;
 
+/* oggz_stream */
+#include "oggz_stream.h"
+
 typedef int (*OggzReadPacket) (OGGZ * oggz, ogg_packet * op, long serialno,
 			       void * user_data);
 typedef int (*OggzReadPage) (OGGZ * oggz, const ogg_page * og, long serialno,
@@ -68,7 +71,7 @@ typedef int (*OggzIOSeek) (void * user_handle, long offset, int whence);
 typedef long (*OggzIOTell) (void * user_handle);
 typedef int (*OggzIOFlush) (void * user_handle);
 
-typedef struct {
+struct _oggz_stream_t {
   ogg_stream_state ogg_stream;
 
   /* non b_o_s packet has been written (not just queued) */
@@ -91,7 +94,7 @@ typedef struct {
 
   OggzReadPage read_page;
   void * read_page_user_data;
-} oggz_stream_t;
+};
 
 struct _OggzReader {
   ogg_sync_state ogg_sync;
@@ -207,9 +210,6 @@ OGGZ * oggz_write_init (OGGZ * oggz);
 int oggz_write_flush (OGGZ * oggz);
 OGGZ * oggz_write_close (OGGZ * oggz);
 
-oggz_stream_t * oggz_get_stream (OGGZ * oggz, long serialno);
-oggz_stream_t * oggz_add_stream (OGGZ * oggz, long serialno);
-
 int oggz_get_bos (OGGZ * oggz, long serialno);
 ogg_int64_t oggz_get_unit (OGGZ * oggz, long serialno, ogg_int64_t granulepos);
 
diff --git a/src/liboggz/oggz_stream.h b/src/liboggz/oggz_stream.h
new file mode 100644
index 0000000000000000000000000000000000000000..bdabaf778a33733c5b5e88cf8d49a900b0c12064
--- /dev/null
+++ b/src/liboggz/oggz_stream.h
@@ -0,0 +1,43 @@
+/*
+   Copyright (C) 2003 Commonwealth Scientific and Industrial Research
+   Organisation (CSIRO) Australia
+
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions
+   are met:
+
+   - Redistributions of source code must retain the above copyright
+   notice, this list of conditions and the following disclaimer.
+
+   - Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
+
+   - Neither the name of CSIRO Australia nor the names of its
+   contributors may be used to endorse or promote products derived from
+   this software without specific prior written permission.
+
+   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+   ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+   PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE ORGANISATION OR
+   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#ifndef __OGGZ_STREAM_H__
+#define __OGGZ_STREAM_H__
+
+typedef struct _oggz_stream_t oggz_stream_t;
+
+oggz_stream_t * oggz_get_stream (OGGZ * oggz, long serialno);
+oggz_stream_t * oggz_add_stream (OGGZ * oggz, long serialno);
+
+int oggz_stream_has_metric (OGGZ * oggz, long serialno);
+
+#endif /* __OGGZ_STREAM_H__ */