diff -u -p -r1.24 Makefile.am
--- ext/vorbis/Makefile.am	22 Nov 2005 11:33:07 -0000	1.24
+++ ext/vorbis/Makefile.am	21 May 2006 12:29:15 -0000
@@ -1,7 +1,7 @@
 plugin_LTLIBRARIES = libgstvorbis.la
 
 libgstvorbis_la_SOURCES = vorbis.c \
-	vorbisdec.c vorbisenc.c vorbisparse.c
+	vorbisdec.c vorbisenc.c vorbisparse.c vorbistag.c
 libgstvorbis_la_CFLAGS = $(GST_CFLAGS) $(VORBIS_CFLAGS) 
 
 ## AM_PATH_VORBIS also sets VORBISENC_LIBS
@@ -12,4 +12,4 @@ libgstvorbis_la_LIBADD = \
 	$(GST_LIBS) \
 	$(VORBIS_LIBS) $(VORBISENC_LIBS)
 
-noinst_HEADERS = vorbisenc.h vorbisdec.h vorbisparse.h
+noinst_HEADERS = vorbisenc.h vorbisdec.h vorbisparse.h vorbistag.h
diff -u -p -r1.32 vorbis.c
--- ext/vorbis/vorbis.c	7 Feb 2006 18:32:00 -0000	1.32
+++ ext/vorbis/vorbis.c	21 May 2006 12:29:15 -0000
@@ -26,10 +26,12 @@
 #include "vorbisenc.h"
 #include "vorbisdec.h"
 #include "vorbisparse.h"
+#include "vorbistag.h"
 
 GST_DEBUG_CATEGORY (vorbisenc_debug);
 GST_DEBUG_CATEGORY (vorbisdec_debug);
 GST_DEBUG_CATEGORY (vorbisparse_debug);
+GST_DEBUG_CATEGORY (vorbistag_debug);
 
 static gboolean
 plugin_init (GstPlugin * plugin)
@@ -46,12 +48,18 @@ plugin_init (GstPlugin * plugin)
           gst_vorbis_parse_get_type ()))
     return FALSE;
 
+  if (!gst_element_register (plugin, "vorbistag", GST_RANK_NONE,
+          gst_vorbis_tag_get_type ()))
+    return FALSE;
+
   GST_DEBUG_CATEGORY_INIT (vorbisenc_debug, "vorbisenc", 0,
       "vorbis encoding element");
   GST_DEBUG_CATEGORY_INIT (vorbisdec_debug, "vorbisdec", 0,
       "vorbis decoding element");
   GST_DEBUG_CATEGORY_INIT (vorbisparse_debug, "vorbisparse", 0,
       "vorbis parsing element");
+  GST_DEBUG_CATEGORY_INIT (vorbistag_debug, "vorbistag", 0,
+      "vorbis tagging element");
 
   gst_tag_register_musicbrainz_tags ();
 
diff -u -p -r1.34 Makefile.am
--- tests/check/Makefile.am	18 May 2006 19:21:53 -0000	1.34
+++ tests/check/Makefile.am	21 May 2006 12:29:15 -0000
@@ -28,7 +28,7 @@ check_alsa =
 endif
 
 if USE_VORBIS
-check_vorbis = elements/vorbisdec pipelines/vorbisenc
+check_vorbis = elements/vorbisdec pipelines/vorbisenc elements/vorbistag
 else
 check_vorbis =
 endif
@@ -102,6 +102,14 @@ elements_audioconvert_CFLAGS = \
 	-I$(top_srcdir)/gst-libs \
 	$(CFLAGS) $(AM_CFLAGS)
 
+elements_vorbistag_LDADD = \
+	$(VORBIS_LIBS) \
+	$(LDADD)
+
+elements_vorbistag_CFLAGS = \
+	$(VORBIS_CFLAGS) \
+	$(CFLAGS) $(AM_CFLAGS)
+
 libs_video_LDADD = \
 	$(top_builddir)/gst-libs/gst/video/libgstvideo-@GST_MAJORMINOR@.la \
 	$(LDADD)
--- /dev/null	2006-05-17 03:49:49.000000000 +1000
+++ tests/check/elements/vorbistag.c	2006-05-21 22:27:59.000000000 +1000
@@ -0,0 +1,396 @@
+/* GStreamer
+ *
+ * unit test for vorbistag
+ *
+ * Copyright (C) 2006  James Livingston  <doclivingston at gmail dot com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include <unistd.h>
+#include <glib.h>
+
+#include <vorbis/codec.h>
+
+#include <gst/gsttagsetter.h>
+#include <gst/check/gstcheck.h>
+
+/* a valid first header packet */
+guchar identification_header[] = {
+  1,                            /* packet_type */
+  'v', 'o', 'r', 'b', 'i', 's',
+  0, 0, 0, 0,                   /* vorbis_version */
+  2,                            /* audio_channels */
+  0x44, 0xac, 0, 0,             /* sample_rate */
+  0xff, 0xff, 0xff, 0xff,       /* bitrate_maximum */
+  0x00, 0xee, 0x02, 0x00,       /* bitrate_nominal */
+  0xff, 0xff, 0xff, 0xff,       /* bitrate_minimum */
+  0xb8,                         /* blocksize_0, blocksize_1 */
+  0x01,                         /* framing_flag */
+};
+
+guchar artist_comment_header[] = {
+  3,                            /* packet_type */
+  'v', 'o', 'r', 'b', 'i', 's',
+  2, 0, 0, 0,                   /* vendor_length */
+  'm', 'e',
+  1, 0, 0, 0,                   /* user_comment_list_length */
+  9, 0, 0, 0,                   /* length comment[0] */
+  'A', 'R', 'T', 'I', 'S', 'T', '=', 'm', 'e',
+  0x01,                         /* framing bit */
+};
+
+guchar title_comment_header[] = {
+  3,                            /* packet_type */
+  'v', 'o', 'r', 'b', 'i', 's',
+  2, 0, 0, 0,                   /* vendor_length */
+  'm', 'e',
+  1, 0, 0, 0,                   /* user_comment_list_length */
+  12, 0, 0, 0,                   /* length comment[0] */
+  'T', 'I', 'T', 'L', 'E', '=', 'f', 'o', 'o', 'b', 'a', 'r',
+  0x01,                         /* framing bit */
+};
+
+guchar empty_comment_header[] = {
+  3,                            /* packet_type */
+  'v', 'o', 'r', 'b', 'i', 's',
+  2, 0, 0, 0,                   /* vendor_length */
+  'm', 'e',
+  0, 0, 0, 0,                   /* user_comment_list_length */
+  0x01,                         /* framing bit */
+};
+
+
+static GstStaticPadTemplate sinktemplate = GST_STATIC_PAD_TEMPLATE ("sink",
+    GST_PAD_SINK,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS_ANY);
+static GstStaticPadTemplate srctemplate = GST_STATIC_PAD_TEMPLATE ("src",
+    GST_PAD_SRC,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS_ANY);
+
+GstPad *mysrcpad, *mysinkpad;
+GAsyncQueue *pending_buffers;
+static gulong id;
+
+
+GstElement *
+setup_vorbistag ()
+{
+  GstElement *vorbistag;
+
+  GST_DEBUG ("setup_vorbistag");
+  vorbistag = gst_check_setup_element ("vorbistag");
+  mysrcpad = gst_check_setup_src_pad (vorbistag, &srctemplate, NULL);
+  mysinkpad = gst_check_setup_sink_pad (vorbistag, &sinktemplate, NULL);
+
+  return vorbistag;
+}
+
+void
+cleanup_vorbistag (GstElement * vorbistag)
+{
+  GST_DEBUG ("cleanup_vorbistag");
+  gst_element_set_state (vorbistag, GST_STATE_NULL);
+
+  gst_check_teardown_src_pad (vorbistag);
+  gst_check_teardown_sink_pad (vorbistag);
+  gst_check_teardown_element (vorbistag);
+}
+
+
+static gboolean
+buffer_probe (GstPad * pad, GstBuffer * buffer, gpointer unused)
+{
+  g_async_queue_push (pending_buffers, gst_buffer_ref (buffer));
+  return TRUE;
+}
+
+static void
+start_pipeline (GstElement *element)
+{
+  id = gst_pad_add_buffer_probe (mysinkpad, G_CALLBACK (buffer_probe), NULL);
+
+  pending_buffers = g_async_queue_new ();
+  gst_element_set_state (element, GST_STATE_PLAYING);
+}
+
+static GstBuffer *
+get_buffer ()
+{
+  return GST_BUFFER (g_async_queue_pop (pending_buffers));
+}
+
+static void
+stop_pipeline (GstElement *element)
+{
+  GstBuffer *buf;
+
+  gst_pad_remove_buffer_probe (mysinkpad, (guint) id);
+  id = 0;
+
+  gst_element_set_state (element, GST_STATE_NULL);
+
+  while (buf = g_async_queue_try_pop (pending_buffers))
+    gst_buffer_unref (buf);
+
+  g_async_queue_unref (pending_buffers);
+  pending_buffers = NULL;
+}
+
+vorbis_comment vc;
+vorbis_dsp_state  vd;
+vorbis_info vi;
+vorbis_block vb;
+
+static GstBuffer *
+_create_codebook_header_buffer ()
+{
+  GstBuffer *buffer;
+  ogg_packet header;
+  ogg_packet header_comm;
+  ogg_packet header_code;
+
+  vorbis_info_init (&vi);
+  vorbis_encode_setup_vbr (&vi, 1, 44000, 0.5);
+  vorbis_encode_setup_init (&vi);
+  vorbis_analysis_init(&vd, &vi);
+  vorbis_block_init (&vd, &vb);
+  vorbis_comment_init (&vc);
+  vorbis_analysis_headerout (&vd, &vc, &header, &header_comm, &header_code);
+
+  buffer = gst_buffer_new_and_alloc (header_code.bytes);
+  memcpy (GST_BUFFER_DATA (buffer), header_code.packet, header_code.bytes);
+
+  return buffer;
+}
+
+static GstBuffer *
+_create_audio_buffer ()
+{
+  GstBuffer *buffer;
+  ogg_packet packet;
+  float **vorbis_buffer;
+
+  vorbis_buffer = vorbis_analysis_buffer (&vd, 0);
+  vorbis_analysis_wrote (&vd, 0);
+  vorbis_analysis_blockout (&vd, &vb);
+  vorbis_analysis (&vb, NULL);
+  vorbis_bitrate_addblock (&vb);
+  vorbis_bitrate_flushpacket (&vd, &packet);
+  buffer = gst_buffer_new_and_alloc (packet.bytes);
+  memcpy (GST_BUFFER_DATA (buffer), packet.packet, packet.bytes);
+
+  vorbis_comment_clear (&vc);
+  vorbis_info_clear (&vi);
+  vorbis_block_clear (&vb);
+
+  return buffer;
+}
+
+
+GST_START_TEST (test_empty_tags_set)
+{
+  GstTagList *tags;
+  GstElement *vorbistag;
+  GstBuffer *inbuffer, *outbuffer;
+  int i;
+
+  vorbistag = setup_vorbistag ();
+
+  tags = gst_tag_list_new ();
+  gst_tag_list_add (tags, GST_TAG_MERGE_REPLACE,
+                    GST_TAG_TITLE, "foobar", NULL);
+  gst_tag_setter_merge_tags (GST_TAG_SETTER (vorbistag), tags, GST_TAG_MERGE_REPLACE);
+  gst_tag_setter_set_tag_merge_mode (GST_TAG_SETTER (vorbistag), GST_TAG_MERGE_KEEP_ALL);
+  gst_tag_list_free (tags);
+
+  start_pipeline (vorbistag);
+
+  /* send identification header */
+  inbuffer = gst_buffer_new_and_alloc (sizeof (identification_header));
+  memcpy (GST_BUFFER_DATA (inbuffer), identification_header, sizeof (identification_header));
+  fail_unless_equals_int (gst_pad_push (mysrcpad, inbuffer), GST_FLOW_OK);
+
+  /* send empty comment buffer */
+  inbuffer = gst_buffer_new_and_alloc (sizeof (empty_comment_header));
+  memcpy (GST_BUFFER_DATA (inbuffer), empty_comment_header, sizeof (empty_comment_header));
+  fail_unless_equals_int (gst_pad_push (mysrcpad, inbuffer), GST_FLOW_OK);
+
+  /* send minimal codebook header and audio packers */
+  inbuffer = _create_codebook_header_buffer ();
+  fail_unless_equals_int (gst_pad_push (mysrcpad, inbuffer), GST_FLOW_OK);
+  inbuffer = _create_audio_buffer ();
+  fail_unless_equals_int (gst_pad_push (mysrcpad, inbuffer), GST_FLOW_OK);
+
+
+  /* check identification header is unchanged */
+  outbuffer = get_buffer ();
+  fail_unless_equals_int (GST_BUFFER_SIZE (outbuffer), sizeof (identification_header));
+  fail_unless_equals_int (memcmp (GST_BUFFER_DATA (outbuffer), identification_header, sizeof (identification_header)), 0);
+  gst_buffer_unref (outbuffer);
+
+  /* check comment header is correct */
+  outbuffer = get_buffer ();
+  fail_unless_equals_int (GST_BUFFER_SIZE (outbuffer), sizeof (title_comment_header));
+  fail_unless_equals_int (memcmp (GST_BUFFER_DATA (outbuffer), title_comment_header, sizeof (title_comment_header)), 0);
+  gst_buffer_unref (outbuffer);
+  
+  stop_pipeline (vorbistag);
+  cleanup_vorbistag (vorbistag);
+}
+
+GST_END_TEST;
+
+
+GST_START_TEST (test_filled_tags_unset)
+{
+  GstTagList *tags;
+  GstElement *vorbistag;
+  GstBuffer *inbuffer, *outbuffer;
+  int i;
+
+  vorbistag = setup_vorbistag ();
+
+  tags = gst_tag_list_new ();
+  gst_tag_setter_merge_tags (GST_TAG_SETTER (vorbistag), tags, GST_TAG_MERGE_REPLACE);
+  gst_tag_setter_set_tag_merge_mode (GST_TAG_SETTER (vorbistag), GST_TAG_MERGE_KEEP_ALL);
+  gst_tag_list_free (tags);
+
+  start_pipeline (vorbistag);
+
+  /* send identification header */
+  inbuffer = gst_buffer_new_and_alloc (sizeof (identification_header));
+  memcpy (GST_BUFFER_DATA (inbuffer), identification_header, sizeof (identification_header));
+  fail_unless_equals_int (gst_pad_push (mysrcpad, inbuffer), GST_FLOW_OK);
+
+  /* send empty comment buffer */
+  inbuffer = gst_buffer_new_and_alloc (sizeof (title_comment_header));
+  memcpy (GST_BUFFER_DATA (inbuffer), title_comment_header, sizeof (title_comment_header));
+  fail_unless_equals_int (gst_pad_push (mysrcpad, inbuffer), GST_FLOW_OK);
+
+  /* send minimal codebook header and audio packers */
+  inbuffer = _create_codebook_header_buffer ();
+  fail_unless_equals_int (gst_pad_push (mysrcpad, inbuffer), GST_FLOW_OK);
+  inbuffer = _create_audio_buffer ();
+  fail_unless_equals_int (gst_pad_push (mysrcpad, inbuffer), GST_FLOW_OK);
+
+
+  /* check identification header is unchanged */
+  outbuffer = get_buffer ();
+  fail_unless_equals_int (GST_BUFFER_SIZE (outbuffer), sizeof (identification_header));
+  fail_unless_equals_int (memcmp (GST_BUFFER_DATA (outbuffer), identification_header, sizeof (identification_header)), 0);
+  gst_buffer_unref (outbuffer);
+
+  /* check comment header is correct */
+  outbuffer = get_buffer ();
+  fail_unless_equals_int (GST_BUFFER_SIZE (outbuffer), sizeof (empty_comment_header));
+  fail_unless_equals_int (memcmp (GST_BUFFER_DATA (outbuffer), empty_comment_header, sizeof (empty_comment_header)), 0);
+  gst_buffer_unref (outbuffer);
+
+  stop_pipeline (vorbistag);
+  cleanup_vorbistag (vorbistag);
+}
+
+GST_END_TEST;
+
+
+GST_START_TEST (test_filled_tags_change)
+{
+  GstTagList *tags;
+  GstElement *vorbistag;
+  GstBuffer *inbuffer, *outbuffer;
+  int i;
+
+  vorbistag = setup_vorbistag ();
+
+  tags = gst_tag_list_new ();
+  gst_tag_list_add (tags, GST_TAG_MERGE_REPLACE,
+                    GST_TAG_TITLE, "foobar", NULL);
+  gst_tag_setter_merge_tags (GST_TAG_SETTER (vorbistag), tags, GST_TAG_MERGE_REPLACE);
+  gst_tag_setter_set_tag_merge_mode (GST_TAG_SETTER (vorbistag), GST_TAG_MERGE_KEEP_ALL);
+  gst_tag_list_free (tags);
+
+  start_pipeline (vorbistag);
+
+  /* send identification header */
+  inbuffer = gst_buffer_new_and_alloc (sizeof (identification_header));
+  memcpy (GST_BUFFER_DATA (inbuffer), identification_header, sizeof (identification_header));
+  fail_unless_equals_int (gst_pad_push (mysrcpad, inbuffer), GST_FLOW_OK);
+
+  /* send empty comment buffer */
+  inbuffer = gst_buffer_new_and_alloc (sizeof (artist_comment_header));
+  memcpy (GST_BUFFER_DATA (inbuffer), artist_comment_header, sizeof (artist_comment_header));
+  fail_unless_equals_int (gst_pad_push (mysrcpad, inbuffer), GST_FLOW_OK);
+
+  /* send minimal codebook header and audio packers */
+  inbuffer = _create_codebook_header_buffer ();
+  fail_unless_equals_int (gst_pad_push (mysrcpad, inbuffer), GST_FLOW_OK);
+  inbuffer = _create_audio_buffer ();
+  fail_unless_equals_int (gst_pad_push (mysrcpad, inbuffer), GST_FLOW_OK);
+
+
+  /* check identification header is unchanged */
+  outbuffer = get_buffer ();
+  fail_unless_equals_int (GST_BUFFER_SIZE (outbuffer), sizeof (identification_header));
+  fail_unless_equals_int (memcmp (GST_BUFFER_DATA (outbuffer), identification_header, sizeof (identification_header)), 0);
+  gst_buffer_unref (outbuffer);
+
+  /* check comment header is correct */
+  outbuffer = get_buffer ();
+  fail_unless_equals_int (GST_BUFFER_SIZE (outbuffer), sizeof (title_comment_header));
+  fail_unless_equals_int (memcmp (GST_BUFFER_DATA (outbuffer), title_comment_header, sizeof (title_comment_header)), 0);
+  gst_buffer_unref (outbuffer);
+
+  stop_pipeline (vorbistag);
+  cleanup_vorbistag (vorbistag);
+}
+
+GST_END_TEST;
+
+
+
+Suite *
+vorbistag_suite (void)
+{
+  Suite *s = suite_create ("vorbistag");
+  TCase *tc_chain = tcase_create ("general");
+
+  suite_add_tcase (s, tc_chain);
+  tcase_add_test (tc_chain, test_empty_tags_set);
+  tcase_add_test (tc_chain, test_filled_tags_unset);
+  tcase_add_test (tc_chain, test_filled_tags_change);
+
+  return s;
+}
+
+int
+main (int argc, char **argv)
+{
+  int nf;
+
+  Suite *s = vorbistag_suite ();
+  SRunner *sr = srunner_create (s);
+
+  gst_check_init (&argc, &argv);
+
+  srunner_run_all (sr, CK_NORMAL);
+  nf = srunner_ntests_failed (sr);
+  srunner_free (sr);
+
+  return nf;
+}
--- /dev/null	2006-05-17 03:49:49.000000000 +1000
+++ ext/vorbis/vorbistag.h	2006-05-19 12:58:06.000000000 +1000
@@ -0,0 +1,65 @@
+/* -*- c-basic-offset: 2 -*-
+ * GStreamer
+ * Copyright (C) <2006> James Livingston <doclivingston@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+
+#ifndef __GST_VORBIS_TAG_H__
+#define __GST_VORBIS_TAG_H__
+
+#include "vorbisparse.h"
+
+
+G_BEGIN_DECLS
+
+
+#define GST_TYPE_VORBIS_TAG \
+  (gst_vorbis_tag_get_type())
+#define GST_VORBIS_TAG(obj) \
+  (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_VORBIS_TAG,GstVorbisTag))
+#define GST_VORBIS_TAG_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_VORBIS_TAG,GstVorbisTag))
+#define GST_IS_VORBIS_TAG(obj) \
+  (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_VORBIS_TAG))
+#define GST_IS_VORBIS_TAG_CLASS(obj) \
+  (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_VORBIS_TAG))
+
+
+typedef struct _GstVorbisTag GstVorbisTag;
+typedef struct _GstVorbisTagClass GstVorbisTagClass;
+
+/**
+ * GstVorbisTag:
+ *
+ * Opaque data structure.
+ */
+struct _GstVorbisTag {
+  GstVorbisParse        parse;
+
+  GstPadChainFunction   parent_chain;
+};
+
+struct _GstVorbisTagClass {
+  GstVorbisParseClass parent_class;
+};
+
+GType gst_vorbis_tag_get_type(void);
+
+G_END_DECLS
+
+#endif /* __GST_VORBIS_TAG_H__ */
--- /dev/null	2006-05-17 03:49:49.000000000 +1000
+++ ext/vorbis/vorbistag.c	2006-05-21 22:39:54.000000000 +1000
@@ -0,0 +1,161 @@
+/*
+ * Copyright (C) 2006 James Livingston <doclivingston@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+/**
+ * SECTION:element-vorbistag
+ * @see_also: #oggdemux, #oggmux, #vorbisparse, #GstTagSetter
+ * @short_description: retags vorbis streams 
+ *
+ * <refsect2>
+ * <para>
+ * The vorbistags element can change the tag contained within a raw
+ * vorbis stream. Specifically, it modifies the comments header packet
+ * of the vorbis stream.
+ * </para>
+ * <para>
+ * The element will also process the stream as the #vorbisparse element does
+ * so it can be used when remuxing an Ogg Vorbis stream, without additional
+ * elements.
+ * </para>
+ * <para>
+ * Applications can set the tags to write using the #GstTagSetter interface.
+ * Tags contained withing the vorbis bitstream will be picked up
+ * automatically (and merged according to the merge mode set via the tag
+ * setter interface).
+ * </para>
+ * <title>Example pipelines</title>
+ * <para>
+ * This element is not useful with gst-launch, because it does not support
+ * setting the tags on a #GstTagSetter interface. Conceptually, the element
+ * will usually be used like:
+ * <programlisting>
+ * gst-launch -v filesrc location=foo.ogg ! oggdemux ! vorbistag ! oggmux ! filesink location=bar.ogg
+ * </programlisting>
+ * </para>
+ * </refsect2>
+ */
+
+#ifdef HAVE_CONFIG_H
+#  include "config.h"
+#endif
+
+#include <glib.h>
+#include <gst/tag/tag.h>
+#include <gst/gsttagsetter.h>
+
+#include <vorbis/codec.h>
+
+#include "vorbistag.h"
+
+
+GST_DEBUG_CATEGORY_EXTERN (vorbisparse_debug);
+#define GST_CAT_DEFAULT vorbisparse_debug
+
+static void gst_vorbis_tag_base_init (gpointer g_class);
+static void gst_vorbis_tag_class_init (GstVorbisTagClass *klass);
+static void gst_vorbis_tag_init (GstVorbisTag *tagger, GstVorbisTagClass *g_class);
+
+static GstFlowReturn gst_vorbis_tag_chain (GstPad *pad, GstBuffer *buffer);
+
+#define _do_init(type)                                                          \
+  G_STMT_START{                                                                 \
+    static const GInterfaceInfo tag_setter_info = {                             \
+      NULL,                                                                     \
+      NULL,                                                                     \
+      NULL                                                                      \
+    };                                                                          \
+    g_type_add_interface_static (type, GST_TYPE_TAG_SETTER,                     \
+                                 &tag_setter_info);                             \
+  }G_STMT_END
+
+GST_BOILERPLATE_FULL (GstVorbisTag, gst_vorbis_tag, GstElement,
+    GST_TYPE_VORBIS_PARSE, _do_init);
+
+static GstElementDetails vorbis_tag_details = {
+  "VorbisTag",
+  "Formatter/Metadata",
+  "Retags vorbis streams",
+  "James Livingston <doclivingston@gmail.com>"
+};
+
+
+static void
+gst_vorbis_tag_base_init (gpointer g_class)
+{
+  GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
+
+  gst_element_class_set_details (element_class, &vorbis_tag_details);
+}
+
+static void
+gst_vorbis_tag_class_init (GstVorbisTagClass * klass)
+{
+  /*GstElementClass *gstelement_class = GST_ELEMENT_CLASS (klass);*/
+}
+
+static void
+gst_vorbis_tag_init (GstVorbisTag *tagger, GstVorbisTagClass * g_class)
+{
+  /* override vorbisparse's chain function */
+  tagger->parent_chain = GST_VORBIS_PARSE(tagger)->sinkpad->chainfunc;
+  gst_pad_set_chain_function (GST_VORBIS_PARSE(tagger)->sinkpad, gst_vorbis_tag_chain);
+}
+
+
+static GstFlowReturn
+gst_vorbis_tag_chain (GstPad *pad, GstBuffer *buffer)
+{
+  GstVorbisTag *tagger;
+  ogg_packet packet;
+  const GstTagList *user_tags;
+  GstTagList *old_tags, *new_tags;
+  gchar *encoder = NULL;
+  GstBuffer *new_buf;
+
+  tagger = GST_VORBIS_TAG (GST_PAD_PARENT (pad));
+
+  packet.packet = GST_BUFFER_DATA (buffer);
+
+  /* just pass everything except the comments packet */
+  if (packet.packet[0] != 0x03) {
+    return tagger->parent_chain (pad, buffer);
+  }
+
+  old_tags = gst_tag_list_from_vorbiscomment_buffer (buffer, (guint8 *) "\003vorbis", 7, &encoder);
+  user_tags = gst_tag_setter_get_tag_list (GST_TAG_SETTER (tagger));
+ 
+  /* build new tag list */
+  new_tags = gst_tag_list_merge (user_tags, old_tags,
+                                 gst_tag_setter_get_tag_merge_mode (GST_TAG_SETTER (tagger)));
+  gst_tag_list_free (old_tags);
+
+  new_buf = gst_tag_list_to_vorbiscomment_buffer (new_tags, (guint8 *) "\003vorbis", 7, encoder);
+ 
+  GST_BUFFER_OFFSET (new_buf) = GST_BUFFER_OFFSET (buffer);
+  GST_BUFFER_OFFSET_END (new_buf) = GST_BUFFER_OFFSET_END (buffer);
+  GST_BUFFER_DURATION (new_buf) = GST_BUFFER_DURATION (buffer);
+  GST_BUFFER_TIMESTAMP (new_buf) = GST_BUFFER_TIMESTAMP (buffer);
+
+  gst_tag_list_free (new_tags);
+  g_free (encoder);
+  gst_buffer_unref (buffer);
+
+  return tagger->parent_chain (pad, new_buf);
+}
+
