configure.ac: Check for optional dependency on zlib for id3demux

Original commit message from CVS:
* configure.ac:
Check for optional dependency on zlib for id3demux

* gst/id3demux/Makefile.am:
* gst/id3demux/gstid3demux.c: (gst_gst_id3demux_get_type),
(gst_id3demux_base_init), (gst_id3demux_class_init),
(gst_id3demux_reset), (gst_id3demux_init), (gst_id3demux_dispose),
(gst_id3demux_add_srcpad), (gst_id3demux_remove_srcpad),
(gst_id3demux_trim_buffer), (gst_id3demux_chain),
(gst_id3demux_set_property), (gst_id3demux_get_property),
(id3demux_get_upstream_size), (gst_id3demux_srcpad_event),
(gst_id3demux_read_id3v1), (gst_id3demux_read_id3v2),
(gst_id3demux_sink_activate), (gst_id3demux_src_activate_pull),
(gst_id3demux_src_checkgetrange), (gst_id3demux_read_range),
(gst_id3demux_src_getrange), (gst_id3demux_change_state),
(gst_id3demux_pad_query), (gst_id3demux_get_query_types),
(simple_find_peek), (simple_find_suggest),
(gst_id3demux_do_typefind), (gst_id3demux_send_tag_event),
(plugin_init):
* gst/id3demux/gstid3demux.h:
* gst/id3demux/id3tags.c: (read_synch_uint),
(id3demux_read_id3v1_tag), (id3demux_read_id3v2_tag),
(id3demux_id3v2_frame_hdr_size), (convert_fid_to_v240),
(id3demux_id3v2_frames_to_tag_list):
* gst/id3demux/id3tags.h:
* gst/id3demux/id3v2.4.0-frames.txt:
* gst/id3demux/id3v2.4.0-structure.txt:
* gst/id3demux/id3v2frames.c: (id3demux_id3v2_parse_frame),
(parse_comment_frame), (parse_text_identification_frame),
(id3v2_tag_to_taglist), (parse_split_strings):
All new LGPL id3 demuxer. Can use zlib for compressed frames,
otherwise it discards them. Works on my test files.

* gst/wavparse/gstwavparse.c: (gst_wavparse_loop):
Don't send EOS to a non-existing srcpad
The debug category can be static

1 files changed, 1086 insertions, 0 deletions

diff --git a/gst/id3demux/gstid3demux.c b/gst/id3demux/gstid3demux.c
new file mode 100644
index 00000000..4a7a370d
--- /dev/null
+++ b/gst/id3demux/gstid3demux.c
@@ -0,0 +1,1086 @@
+/* -*- Mode: C; tab-width: 2; indent-tabs-mode: t; c-basic-offset: 2 -*- */
+/* Copyright 2005 Jan Schmidt <thaytan@mad.scientist.com>
+ * Copyright (C) 2003-2004 Benjamin Otte <otte@gnome.org>
+ *
+ * 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.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+#include <gst/gst.h>
+#include <gst/gst-i18n-plugin.h>
+
+#include "gstid3demux.h"
+#include "id3tags.h"
+
+enum
+{
+  ARG_0,
+  ARG_PREFER_V1
+};
+
+/* Require at least 4kB of data before we attempt typefind. 
+ * Seems a decent value based on test files
+ * 40kB is massive overkill for the maximum, I think, but it 
+ * doesn't do any harm */
+#define ID3_TYPE_FIND_MIN_SIZE 4096
+#define ID3_TYPE_FIND_MAX_SIZE 40960
+
+GST_DEBUG_CATEGORY (id3demux_debug);
+#define GST_CAT_DEFAULT (id3demux_debug)
+
+static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",
+    GST_PAD_SINK,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS ("application/x-id3")
+    );
+
+static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src",
+    GST_PAD_SRC,
+    GST_PAD_SOMETIMES,
+    GST_STATIC_CAPS ("ANY")
+    );
+
+static void gst_id3demux_class_init (GstID3DemuxClass * klass);
+static void gst_id3demux_base_init (GstID3DemuxClass * klass);
+static void gst_id3demux_init (GstID3Demux * id3demux);
+static void gst_id3demux_dispose (GObject * object);
+
+static void gst_id3demux_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec);
+static void gst_id3demux_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec);
+
+static GstFlowReturn gst_id3demux_chain (GstPad * pad, GstBuffer * buf);
+
+static gboolean gst_id3demux_src_activate_pull (GstPad * pad, gboolean active);
+static GstFlowReturn gst_id3demux_read_range (GstID3Demux * id3demux,
+    guint64 offset, guint length, GstBuffer ** buffer);
+
+static gboolean gst_id3demux_src_checkgetrange (GstPad * srcpad);
+static GstFlowReturn gst_id3demux_src_getrange (GstPad * srcpad,
+    guint64 offset, guint length, GstBuffer ** buffer);
+
+static gboolean gst_id3demux_add_srcpad (GstID3Demux * id3demux,
+    GstCaps * new_caps);
+static gboolean gst_id3demux_remove_srcpad (GstID3Demux * id3demux);
+
+static gboolean gst_id3demux_srcpad_event (GstPad * pad, GstEvent * event);
+static gboolean gst_id3demux_sink_activate (GstPad * sinkpad);
+static GstStateChangeReturn gst_id3demux_change_state (GstElement * element,
+    GstStateChange transition);
+static gboolean gst_id3demux_pad_query (GstPad * pad, GstQuery * query);
+static const GstQueryType *gst_id3demux_get_query_types (GstPad * pad);
+static gboolean id3demux_get_upstream_size (GstID3Demux * id3demux);
+static GstCaps *gst_id3demux_do_typefind (GstID3Demux * id3demux,
+    GstBuffer * buffer);
+static void gst_id3demux_send_tag_event (GstID3Demux * id3demux);
+
+static GstElementClass *parent_class = NULL;
+
+GType
+gst_gst_id3demux_get_type (void)
+{
+  static GType plugin_type = 0;
+
+  if (!plugin_type) {
+    static const GTypeInfo plugin_info = {
+      sizeof (GstID3DemuxClass),
+      (GBaseInitFunc) gst_id3demux_base_init,
+      NULL,
+      (GClassInitFunc) gst_id3demux_class_init,
+      NULL,
+      NULL,
+      sizeof (GstID3Demux),
+      0,
+      (GInstanceInitFunc) gst_id3demux_init,
+    };
+    plugin_type = g_type_register_static (GST_TYPE_ELEMENT,
+        "GstID3Demux", &plugin_info, 0);
+  }
+  return plugin_type;
+}
+
+static void
+gst_id3demux_base_init (GstID3DemuxClass * klass)
+{
+  static GstElementDetails plugin_details = {
+    "GStreamer ID3 Demuxer",
+    "Codec/Demuxer/Metadata",
+    "ID3 tag reader and demuxer",
+    "Jan Schmidt <thaytan@mad.scientist.com>"
+  };
+  GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
+
+  gst_element_class_add_pad_template (element_class,
+      gst_static_pad_template_get (&src_factory));
+  gst_element_class_add_pad_template (element_class,
+      gst_static_pad_template_get (&sink_factory));
+  gst_element_class_set_details (element_class, &plugin_details);
+}
+
+static void
+gst_id3demux_class_init (GstID3DemuxClass * klass)
+{
+  GObjectClass *gobject_class;
+  GstElementClass *gstelement_class;
+
+  gobject_class = (GObjectClass *) klass;
+  gstelement_class = (GstElementClass *) klass;
+
+  parent_class = g_type_class_ref (GST_TYPE_ELEMENT);
+
+  gobject_class->dispose = gst_id3demux_dispose;
+
+  gobject_class->set_property = gst_id3demux_set_property;
+  gobject_class->get_property = gst_id3demux_get_property;
+
+  gstelement_class->change_state = gst_id3demux_change_state;
+
+  g_object_class_install_property (gobject_class, ARG_PREFER_V1,
+      g_param_spec_boolean ("prefer-v1", "Prefer version 1 tag",
+          "Prefer tags from ID3v1 tag at end of file", FALSE,
+          G_PARAM_READWRITE | G_PARAM_CONSTRUCT));
+}
+
+static void
+gst_id3demux_reset (GstID3Demux * id3demux)
+{
+  id3demux->strip_start = 0;
+  id3demux->strip_end = 0;
+  id3demux->upstream_size = -1;
+  id3demux->state = GST_ID3DEMUX_READID3V2;
+  id3demux->send_tag_event = FALSE;
+
+  gst_buffer_replace (&(id3demux->collect), NULL);
+  gst_caps_replace (&(id3demux->src_caps), NULL);
+
+  gst_id3demux_remove_srcpad (id3demux);
+
+  if (id3demux->event_tags) {
+    gst_tag_list_free (id3demux->event_tags);
+    id3demux->event_tags = NULL;
+  }
+  if (id3demux->parsed_tags) {
+    gst_tag_list_free (id3demux->parsed_tags);
+    id3demux->parsed_tags = NULL;
+  }
+
+}
+
+static void
+gst_id3demux_init (GstID3Demux * id3demux)
+{
+  GstElementClass *klass = GST_ELEMENT_GET_CLASS (id3demux);
+
+  id3demux->sinkpad =
+      gst_pad_new_from_template (gst_element_class_get_pad_template (klass,
+          "sink"), "sink");
+  gst_pad_set_activate_function (id3demux->sinkpad,
+      GST_DEBUG_FUNCPTR (gst_id3demux_sink_activate));
+  gst_pad_set_chain_function (id3demux->sinkpad,
+      GST_DEBUG_FUNCPTR (gst_id3demux_chain));
+  gst_element_add_pad (GST_ELEMENT (id3demux), id3demux->sinkpad);
+
+  id3demux->prefer_v1 = FALSE;
+  gst_id3demux_reset (id3demux);
+}
+
+static void
+gst_id3demux_dispose (GObject * object)
+{
+  GstID3Demux *id3demux = GST_ID3DEMUX (object);
+
+  gst_id3demux_reset (id3demux);
+
+  G_OBJECT_CLASS (parent_class)->dispose (object);
+}
+
+static gboolean
+gst_id3demux_add_srcpad (GstID3Demux * id3demux, GstCaps * new_caps)
+{
+  GstPad *srcpad = NULL;
+
+  if (id3demux->src_caps == NULL ||
+      !gst_caps_is_equal (new_caps, id3demux->src_caps)) {
+
+    gst_caps_replace (&(id3demux->src_caps), new_caps);
+    if (id3demux->srcpad != NULL) {
+      GST_DEBUG_OBJECT (id3demux, "Changing src pad caps to %" GST_PTR_FORMAT,
+          id3demux->src_caps);
+
+      gst_pad_set_caps (id3demux->srcpad, id3demux->src_caps);
+    }
+  } else {
+    /* Caps never changed */
+    gst_caps_unref (new_caps);
+  }
+
+  if (id3demux->srcpad == NULL) {
+    srcpad = id3demux->srcpad =
+        gst_pad_new_from_template (gst_element_class_get_pad_template
+        (GST_ELEMENT_GET_CLASS (id3demux), "src"), "src");
+    g_return_val_if_fail (id3demux->srcpad != NULL, FALSE);
+
+    gst_pad_set_query_type_function (id3demux->srcpad,
+        GST_DEBUG_FUNCPTR (gst_id3demux_get_query_types));
+    gst_pad_set_query_function (id3demux->srcpad,
+        GST_DEBUG_FUNCPTR (gst_id3demux_pad_query));
+    gst_pad_set_event_function (id3demux->srcpad,
+        GST_DEBUG_FUNCPTR (gst_id3demux_srcpad_event));
+    gst_pad_set_activatepull_function (id3demux->srcpad,
+        GST_DEBUG_FUNCPTR (gst_id3demux_src_activate_pull));
+    gst_pad_set_checkgetrange_function (id3demux->srcpad,
+        GST_DEBUG_FUNCPTR (gst_id3demux_src_checkgetrange));
+    gst_pad_set_getrange_function (id3demux->srcpad,
+        GST_DEBUG_FUNCPTR (gst_id3demux_src_getrange));
+
+    gst_pad_use_fixed_caps (id3demux->srcpad);
+
+    if (id3demux->src_caps)
+      gst_pad_set_caps (id3demux->srcpad, id3demux->src_caps);
+
+    GST_DEBUG_OBJECT (id3demux, "Adding src pad with caps %" GST_PTR_FORMAT,
+        id3demux->src_caps);
+
+    gst_object_ref (id3demux->srcpad);
+    return gst_element_add_pad (GST_ELEMENT (id3demux), id3demux->srcpad);
+  }
+
+  return TRUE;
+}
+
+static gboolean
+gst_id3demux_remove_srcpad (GstID3Demux * id3demux)
+{
+  if (id3demux->srcpad != NULL) {
+    GST_DEBUG_OBJECT (id3demux, "Removing src pad");
+    g_return_val_if_fail (gst_element_remove_pad (GST_ELEMENT (id3demux),
+            id3demux->srcpad), FALSE);
+    gst_object_unref (id3demux->srcpad);
+    id3demux->srcpad = NULL;
+  }
+
+  return TRUE;
+};
+
+static gboolean
+gst_id3demux_trim_buffer (GstID3Demux * id3demux, GstBuffer ** buf_ref)
+{
+  GstBuffer *buf = *buf_ref;
+
+  guint trim_start = 0;
+  guint out_size = GST_BUFFER_SIZE (buf);
+  guint64 out_offset = GST_BUFFER_OFFSET (buf);
+  gboolean need_sub = FALSE;
+
+  /* Adjust offset and length */
+  if (!GST_BUFFER_OFFSET_IS_VALID (buf)) {
+    /* Can't change anything without an offset */
+    return TRUE;
+  }
+
+  /* If the buffer crosses the ID3v1 tag at the end of file, trim it */
+  if (id3demux->strip_end > 0) {
+    if (id3demux_get_upstream_size (id3demux)) {
+      guint64 v1tag_offset = id3demux->upstream_size - id3demux->strip_end;
+
+      if (out_offset >= v1tag_offset) {
+        GST_DEBUG_OBJECT (id3demux, "Buffer is past the end of the data");
+        goto no_out_buffer;
+      }
+
+      if (out_offset + out_size > v1tag_offset) {
+        out_size = v1tag_offset - out_offset;
+        need_sub = TRUE;
+      }
+    }
+  }
+
+  if (id3demux->strip_start > 0) {
+    /* If the buffer crosses the ID3v2 tag at the start of file, trim it */
+    if (out_offset <= id3demux->strip_start) {
+      if (out_offset + out_size <= id3demux->strip_start) {
+        GST_DEBUG_OBJECT (id3demux, "Buffer is before the start of the data");
+        goto no_out_buffer;
+      }
+
+      trim_start = id3demux->strip_start - out_offset;
+      out_size -= trim_start;
+      out_offset = 0;
+    } else {
+      out_offset -= id3demux->strip_start;
+    }
+    need_sub = TRUE;
+  }
+
+  g_assert (out_size > 0);
+
+  if (need_sub == TRUE) {
+    if (out_size != GST_BUFFER_SIZE (buf) || !gst_buffer_is_writable (buf)) {
+      GstBuffer *sub;
+
+      GST_DEBUG_OBJECT (id3demux, "Sub-buffering to trim size %d offset %"
+          G_GINT64_FORMAT " to %d offset %" G_GINT64_FORMAT,
+          GST_BUFFER_SIZE (buf), GST_BUFFER_OFFSET (buf), out_size, out_offset);
+
+      sub = gst_buffer_create_sub (buf, trim_start, out_size);
+      g_return_val_if_fail (sub != NULL, FALSE);
+      gst_buffer_unref (buf);
+      *buf_ref = buf = sub;
+    } else {
+      GST_DEBUG_OBJECT (id3demux, "Adjusting buffer from size %d offset %"
+          G_GINT64_FORMAT " to %d offset %" G_GINT64_FORMAT,
+          GST_BUFFER_SIZE (buf), GST_BUFFER_OFFSET (buf), out_size, out_offset);
+    }
+
+    GST_BUFFER_OFFSET (buf) = out_offset;
+    GST_BUFFER_OFFSET_END (buf) = out_offset + out_size;
+    gst_buffer_set_caps (buf, id3demux->src_caps);
+  }
+
+  return TRUE;
+no_out_buffer:
+  gst_buffer_unref (buf);
+  *buf_ref = NULL;
+  return TRUE;
+}
+
+static GstFlowReturn
+gst_id3demux_chain (GstPad * pad, GstBuffer * buf)
+{
+  GstID3Demux *id3demux;
+
+  id3demux = GST_ID3DEMUX (GST_PAD_PARENT (pad));
+  g_return_val_if_fail (GST_IS_ID3DEMUX (id3demux), GST_FLOW_ERROR);
+
+  if (id3demux->collect == NULL) {
+    id3demux->collect = buf;
+  } else {
+    id3demux->collect = gst_buffer_join (id3demux->collect, buf);
+  }
+  buf = NULL;
+
+  switch (id3demux->state) {
+    case GST_ID3DEMUX_READID3V2:
+      /* If we receive a buffer that's from the middle of the file, 
+       * we can't read tags so move to typefinding */
+      if (GST_BUFFER_OFFSET (id3demux->collect) != 0) {
+        GST_DEBUG_OBJECT (id3demux,
+            "Received buffer from non-zero offset. Can't read tags");
+        id3demux->state = GST_ID3DEMUX_TYPEFINDING;
+        break;
+      } else {
+        ID3TagsResult tag_result;
+
+        tag_result = id3demux_read_id3v2_tag (id3demux->collect,
+            &id3demux->strip_start, &id3demux->parsed_tags);
+        if (tag_result == ID3TAGS_MORE_DATA)
+          break;                /* Go get more data and try again */
+        else if (tag_result == ID3TAGS_BROKEN_TAG)
+          GST_WARNING_OBJECT (id3demux,
+              "Ignoring broken ID3v2 tag of size %d", id3demux->strip_start);
+        else
+          GST_DEBUG_OBJECT (id3demux, "Found an ID3v2 tag of size %d\n",
+              id3demux->strip_start);
+
+        id3demux->state = GST_ID3DEMUX_TYPEFINDING;
+        id3demux->send_tag_event = TRUE;
+      }
+
+      /* Fall-through */
+    case GST_ID3DEMUX_TYPEFINDING:{
+      GstCaps *caps;
+      GstBuffer *typefind_buf = NULL;
+
+      if (GST_BUFFER_SIZE (id3demux->collect) < ID3_TYPE_FIND_MIN_SIZE)
+        break;                  /* Go get more data first */
+
+      GST_DEBUG_OBJECT (id3demux, "Typefinding with size %d",
+          GST_BUFFER_SIZE (id3demux->collect));
+
+      /* Trim the buffer and adjust offset for typefinding */
+      typefind_buf = id3demux->collect;
+      gst_buffer_ref (typefind_buf);
+      if (!gst_id3demux_trim_buffer (id3demux, &typefind_buf))
+        return GST_FLOW_ERROR;
+
+      caps = gst_id3demux_do_typefind (id3demux, typefind_buf);
+
+      if (caps == NULL) {
+        if (GST_BUFFER_SIZE (typefind_buf) < ID3_TYPE_FIND_MAX_SIZE) {
+          /* Just break for more data */
+          gst_buffer_unref (typefind_buf);
+          return GST_FLOW_OK;
+        }
+
+        /* We failed typefind */
+        GST_ELEMENT_ERROR (id3demux, CORE, CAPS, (NULL), ("no caps found"));
+        gst_buffer_unref (typefind_buf);
+        gst_buffer_unref (id3demux->collect);
+        id3demux->collect = NULL;
+        return GST_FLOW_ERROR;
+      }
+      gst_buffer_unref (typefind_buf);
+
+      if (!gst_id3demux_add_srcpad (id3demux, caps)) {
+        GST_DEBUG_OBJECT (id3demux, "Failed to add srcpad");
+        gst_caps_unref (caps);
+        goto error;
+      }
+      gst_caps_unref (caps);
+
+      /* Move onto streaming and fall-through to push out existing
+       * data */
+      id3demux->state = GST_ID3DEMUX_STREAMING;
+      /* fall-through */
+    }
+    case GST_ID3DEMUX_STREAMING:{
+      GstBuffer *outbuf = NULL;
+
+      if (id3demux->send_tag_event) {
+        gst_id3demux_send_tag_event (id3demux);
+        id3demux->send_tag_event = FALSE;
+      }
+
+      /* Trim the buffer and adjust offset */
+      if (id3demux->collect) {
+        outbuf = id3demux->collect;
+        id3demux->collect = NULL;
+        if (!gst_id3demux_trim_buffer (id3demux, &outbuf))
+          return GST_FLOW_ERROR;
+      }
+      if (outbuf) {
+        if (G_UNLIKELY (id3demux->srcpad == NULL)) {
+          gst_buffer_unref (outbuf);
+          return GST_FLOW_ERROR;
+        }
+
+        GST_DEBUG_OBJECT (id3demux, "Pushing buffer %p", outbuf);
+        return gst_pad_push (id3demux->srcpad, outbuf);
+      }
+    }
+  }
+  return GST_FLOW_OK;
+
+error:
+  GST_DEBUG_OBJECT (id3demux, "error in chain function");
+
+  return GST_FLOW_ERROR;
+}
+
+static void
+gst_id3demux_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec)
+{
+  GstID3Demux *id3demux;
+
+  g_return_if_fail (GST_IS_ID3DEMUX (object));
+  id3demux = GST_ID3DEMUX (object);
+
+  switch (prop_id) {
+    case ARG_PREFER_V1:
+      id3demux->prefer_v1 = g_value_get_boolean (value);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+static void
+gst_id3demux_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec)
+{
+  GstID3Demux *id3demux;
+
+  g_return_if_fail (GST_IS_ID3DEMUX (object));
+  id3demux = GST_ID3DEMUX (object);
+
+  switch (prop_id) {
+    case ARG_PREFER_V1:
+      g_value_set_boolean (value, id3demux->prefer_v1);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+static gboolean
+id3demux_get_upstream_size (GstID3Demux * id3demux)
+{
+  GstQuery *query;
+  GstPad *peer = NULL;
+  GstFormat format;
+  gint64 result;
+  gboolean res = FALSE;
+
+  /* Short-cut if we already queried upstream */
+  if (id3demux->upstream_size > 0)
+    return TRUE;
+
+  if ((peer = gst_pad_get_peer (id3demux->sinkpad)) == NULL)
+    return FALSE;
+
+  query = gst_query_new_duration (GST_FORMAT_BYTES);
+  gst_query_set_duration (query, GST_FORMAT_BYTES, -1);
+
+  if (!gst_pad_query (peer, query))
+    goto out;
+
+  gst_query_parse_duration (query, &format, &result);
+
+  if (format != GST_FORMAT_BYTES || result == -1)
+    goto out;
+
+  id3demux->upstream_size = result;
+  res = TRUE;
+
+out:
+  gst_object_unref (peer);
+  return res;
+}
+
+static gboolean
+gst_id3demux_srcpad_event (GstPad * pad, GstEvent * event)
+{
+  gboolean res = FALSE;
+  GstID3Demux *id3demux = GST_ID3DEMUX (GST_PAD_PARENT (pad));
+
+  /* Handle SEEK events, with adjusted byte offsets and sizes. */
+
+  switch (GST_EVENT_TYPE (event)) {
+    case GST_EVENT_SEEK:
+    {
+      gdouble rate;
+      GstFormat format;
+      GstSeekType cur_type, stop_type;
+      GstSeekFlags flags;
+      gint64 cur, stop;
+
+      gst_event_parse_seek (event, &rate, &format, &flags,
+          &cur_type, &cur, &stop_type, &stop);
+
+      if (format == GST_FORMAT_BYTES &&
+          id3demux->state == GST_ID3DEMUX_STREAMING &&
+          gst_pad_is_linked (id3demux->sinkpad)) {
+        GstEvent *upstream;
+
+        switch (cur_type) {
+          case GST_SEEK_TYPE_SET:
+            cur += id3demux->strip_start;
+            break;
+          case GST_SEEK_TYPE_CUR:
+            break;
+          case GST_SEEK_TYPE_END:
+            cur += id3demux->strip_end;
+            break;
+          default:
+            g_assert_not_reached ();
+            break;
+        }
+        switch (stop_type) {
+          case GST_SEEK_TYPE_SET:
+            stop += id3demux->strip_start;
+            break;
+          case GST_SEEK_TYPE_CUR:
+            break;
+          case GST_SEEK_TYPE_END:
+            stop += id3demux->strip_end;
+            break;
+          default:
+            break;
+        }
+        upstream = gst_event_new_seek (rate, format, flags,
+            cur_type, cur, stop_type, stop);
+        res = gst_pad_push_event (id3demux->sinkpad, upstream);
+      }
+      break;
+    }
+    default:
+      break;
+  }
+
+  gst_event_unref (event);
+  return res;
+}
+
+/* Read and interpret any ID3v1 tag when activating in pull_range */
+static gboolean
+gst_id3demux_read_id3v1 (GstID3Demux * id3demux, GstTagList ** tags)
+{
+  GstBuffer *buffer = NULL;
+  gboolean res = FALSE;
+  ID3TagsResult tag_res;
+  GstFlowReturn flow_ret;
+  guint64 id3v1_offset;
+
+  if (id3demux->upstream_size < ID3V1_TAG_SIZE)
+    return TRUE;
+  id3v1_offset = id3demux->upstream_size - ID3V1_TAG_SIZE;
+
+  flow_ret = gst_pad_pull_range (id3demux->sinkpad, id3v1_offset,
+      ID3V1_TAG_SIZE, &buffer);
+  if (flow_ret != GST_FLOW_OK) {
+    GST_DEBUG_OBJECT (id3demux,
+        "Could not read data from start of file ret=%d", flow_ret);
+    goto beach;
+  }
+
+  if (GST_BUFFER_SIZE (buffer) != ID3V1_TAG_SIZE) {
+    GST_DEBUG_OBJECT (id3demux,
+        "Only managed to read %u bytes from file - not an ID3 file",
+        GST_BUFFER_SIZE (buffer));
+    goto beach;
+  }
+
+  tag_res = id3demux_read_id3v1_tag (buffer, &id3demux->strip_end, tags);
+  if (tag_res == ID3TAGS_READ_TAG) {
+    GST_DEBUG_OBJECT (id3demux, "Read ID3v1 tag");
+    res = TRUE;
+  } else if (tag_res == ID3TAGS_BROKEN_TAG) {
+    GST_WARNING_OBJECT (id3demux, "Ignoring broken ID3v1 tag");
+    res = TRUE;
+  }
+beach:
+  if (buffer)
+    gst_buffer_unref (buffer);
+  return res;
+}
+
+/* Read and interpret any ID3v2 tag when activating in pull_range */
+static gboolean
+gst_id3demux_read_id3v2 (GstID3Demux * id3demux, GstTagList ** tags)
+{
+  GstBuffer *buffer = NULL;
+  gboolean res = FALSE;
+  ID3TagsResult tag_res;
+  GstFlowReturn flow_ret;
+
+  /* Handle ID3V2 tag. Try with 4kB to start with */
+  flow_ret = gst_pad_pull_range (id3demux->sinkpad, 0, 4096, &buffer);
+  if (flow_ret != GST_FLOW_OK) {
+    GST_DEBUG_OBJECT (id3demux,
+        "Could not read data from start of file ret=%d", flow_ret);
+    goto beach;
+  }
+
+  if (GST_BUFFER_SIZE (buffer) < ID3V2_HDR_SIZE) {
+    GST_DEBUG_OBJECT (id3demux,
+        "Only managed to read %u bytes from file - not an ID3 file",
+        GST_BUFFER_SIZE (buffer));
+    goto beach;
+  }
+
+  tag_res = id3demux_read_id3v2_tag (buffer, &id3demux->strip_start, tags);
+  if (tag_res == ID3TAGS_MORE_DATA) {
+    /* Need more data to interpret the tag */
+    if (buffer) {
+      gst_buffer_unref (buffer);
+      buffer = NULL;
+    }
+    g_assert (id3demux->strip_start > ID3V2_HDR_SIZE);
+
+    GST_DEBUG_OBJECT (id3demux, "Reading %u bytes to decode ID3v2",
+        id3demux->strip_start);
+    flow_ret = gst_pad_pull_range (id3demux->sinkpad, 0, id3demux->strip_start,
+        &buffer);
+    if (flow_ret != GST_FLOW_OK) {
+      GST_DEBUG_OBJECT (id3demux,
+          "Could not read data from start of file ret=%d", flow_ret);
+      goto beach;
+    }
+    tag_res = id3demux_read_id3v2_tag (buffer, &id3demux->strip_start, tags);
+  }
+
+  if (tag_res == ID3TAGS_READ_TAG) {
+    res = TRUE;
+    GST_DEBUG_OBJECT (id3demux, "Read ID3v2 tag of size %d",
+        id3demux->strip_start);
+  } else if (tag_res == ID3TAGS_BROKEN_TAG) {
+    res = TRUE;
+    GST_WARNING_OBJECT (id3demux, "Ignoring broken ID3v2 tag of size %d",
+        id3demux->strip_start);
+  }
+beach:
+  if (buffer)
+    gst_buffer_unref (buffer);
+  return res;
+}
+
+/* This function operates similarly to gst_type_find_element_activate
+ * in the typefind element
+ * 1. try to activate in pull mode. if not, switch to push and succeed.
+ * 2. try to read tags in pull mode
+ * 3. typefind the contents
+ * 4. deactivate pull mode.
+ * 5. if we didn't find any caps, fail.
+ * 6. Add the srcpad
+ * 7. if the sink pad is activated, we are in pull mode. succeed.
+ *    otherwise activate both pads in push mode and succeed.
+ */
+static gboolean
+gst_id3demux_sink_activate (GstPad * sinkpad)
+{
+  GstID3Demux *id3demux = GST_ID3DEMUX (GST_PAD_PARENT (sinkpad));
+  gboolean ret = FALSE;
+  GstBuffer *buf = NULL;
+  GstCaps *caps = NULL;
+  GstFlowReturn flow_ret;
+
+  /* 1: */
+  /* If we can activate pull_range upstream, then read any ID3v1 and ID3v2
+   * tags, otherwise activate in push mode and the chain function will 
+   * collect buffers, read the ID3v2 tag and output a buffer to end
+   * preroll.
+   */
+  if (!gst_pad_check_pull_range (sinkpad) ||
+      !gst_pad_activate_pull (sinkpad, TRUE)) {
+    GST_DEBUG_OBJECT (id3demux,
+        "No pull mode. Changing to push, but won't be able to read ID3v1 tags");
+    id3demux->state = GST_ID3DEMUX_READID3V2;
+    return gst_pad_activate_push (sinkpad, TRUE);
+  }
+
+  /* Look for tags at start and end of file */
+  GST_DEBUG_OBJECT (id3demux, "Activated pull mode. Looking for tags");
+  if (!id3demux_get_upstream_size (id3demux))
+    return FALSE;
+
+  id3demux->strip_start = 0;
+  id3demux->strip_end = 0;
+
+
+  if (id3demux->prefer_v1) {
+    if (!gst_id3demux_read_id3v2 (id3demux, &(id3demux->parsed_tags)))
+      return FALSE;
+    if (!gst_id3demux_read_id3v1 (id3demux, &(id3demux->parsed_tags)))
+      return FALSE;
+  } else {
+    if (!gst_id3demux_read_id3v1 (id3demux, &(id3demux->parsed_tags)))
+      return FALSE;
+    if (!gst_id3demux_read_id3v2 (id3demux, &(id3demux->parsed_tags)))
+      return FALSE;
+  }
+  if (id3demux->parsed_tags != NULL) {
+    id3demux->send_tag_event = TRUE;
+  }
+
+  flow_ret =
+      gst_id3demux_read_range (id3demux, 0, ID3_TYPE_FIND_MAX_SIZE, &buf);
+  if (flow_ret != GST_FLOW_OK) {
+    GST_DEBUG_OBJECT (id3demux, "Could not read data from start of file ret=%d",
+        flow_ret);
+    goto done_activate;
+  }
+
+  caps = gst_id3demux_do_typefind (id3demux, buf);
+  gst_buffer_unref (buf);
+  buf = NULL;
+
+  /* 4 - Deactivate pull mode */
+  if (!gst_pad_activate_pull (sinkpad, FALSE)) {
+    if (caps)
+      gst_caps_unref (caps);
+    GST_DEBUG_OBJECT (id3demux,
+        "Could not deactivate sinkpad after reading tags");
+    return FALSE;
+  }
+
+  /* 5 - If we didn't find the caps, fail */
+  if (caps == NULL) {
+    GST_DEBUG_OBJECT (id3demux, "Could not detect type of contents");
+    goto done_activate;
+  }
+
+  /* tag reading and typefinding were already done, don't do them again in
+     the chain function if we end up in push mode */
+  id3demux->state = GST_ID3DEMUX_STREAMING;
+
+  /* 6 Add the srcpad for output now we know caps. */
+  /* add_srcpad takes ownership of the caps */
+  if (!gst_id3demux_add_srcpad (id3demux, caps)) {
+    GST_DEBUG_OBJECT (id3demux, "Could not add source pad");
+    goto done_activate;
+  }
+
+  /* 7 - if the sinkpad is active, it was done by downstream so we're 
+   * done, otherwise switch to push */
+  ret = TRUE;
+  if (!gst_pad_is_active (sinkpad)) {
+    ret = gst_pad_activate_push (id3demux->srcpad, TRUE);
+    ret &= gst_pad_activate_push (sinkpad, TRUE);
+  }
+
+done_activate:
+  if (buf)
+    gst_buffer_unref (buf);
+
+  return ret;
+}
+
+static gboolean
+gst_id3demux_src_activate_pull (GstPad * pad, gboolean active)
+{
+  GstID3Demux *id3demux = GST_ID3DEMUX (GST_PAD_PARENT (pad));
+
+  return gst_pad_activate_pull (id3demux->sinkpad, active);
+}
+
+static gboolean
+gst_id3demux_src_checkgetrange (GstPad * srcpad)
+{
+  GstID3Demux *id3demux = GST_ID3DEMUX (GST_PAD_PARENT (srcpad));
+
+  return gst_pad_check_pull_range (id3demux->sinkpad);
+}
+
+static GstFlowReturn
+gst_id3demux_read_range (GstID3Demux * id3demux,
+    guint64 offset, guint length, GstBuffer ** buffer)
+{
+  GstFlowReturn ret;
+  guint64 in_offset;
+  guint in_length;
+
+  g_return_val_if_fail (buffer != NULL, GST_FLOW_ERROR);
+
+  /* Adjust offset and length of the request to trim off ID3 information. 
+   * For the returned buffer, adjust the output offset to match what downstream
+   * should see */
+  in_offset = offset + id3demux->strip_start;
+
+  if (!id3demux_get_upstream_size (id3demux))
+    return GST_FLOW_ERROR;
+
+  if (in_offset + length >= id3demux->upstream_size - id3demux->strip_end)
+    in_length = id3demux->upstream_size - id3demux->strip_end - in_offset;
+  else
+    in_length = length;
+
+  ret = gst_pad_pull_range (id3demux->sinkpad, in_offset, in_length, buffer);
+
+  if (ret == GST_FLOW_OK && *buffer) {
+    if (!gst_id3demux_trim_buffer (id3demux, buffer))
+      goto error;
+  }
+
+  return ret;
+error:
+  if (*buffer != NULL) {
+    gst_buffer_unref (buffer);
+    *buffer = NULL;
+  }
+  return GST_FLOW_ERROR;
+}
+
+static GstFlowReturn
+gst_id3demux_src_getrange (GstPad * srcpad,
+    guint64 offset, guint length, GstBuffer ** buffer)
+{
+  GstID3Demux *id3demux = GST_ID3DEMUX (GST_PAD_PARENT (srcpad));
+
+  if (id3demux->send_tag_event) {
+    gst_id3demux_send_tag_event (id3demux);
+    id3demux->send_tag_event = FALSE;
+  }
+  return gst_id3demux_read_range (id3demux, offset, length, buffer);
+}
+
+static GstStateChangeReturn
+gst_id3demux_change_state (GstElement * element, GstStateChange transition)
+{
+  GstStateChangeReturn ret;
+  GstID3Demux *id3demux = GST_ID3DEMUX (element);
+
+  ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
+
+  switch (transition) {
+    case GST_STATE_CHANGE_PAUSED_TO_READY:
+      gst_id3demux_reset (id3demux);
+      break;
+    default:
+      break;
+  }
+  return ret;
+}
+
+static gboolean
+gst_id3demux_pad_query (GstPad * pad, GstQuery * query)
+{
+  /* For a position or duration query, adjust the returned
+   * bytes to strip off the id3v1 and id3v2 areas */
+
+  GstID3Demux *id3demux = GST_ID3DEMUX (GST_PAD_PARENT (pad));
+  GstPad *peer = NULL;
+  GstFormat format;
+  gint64 result;
+
+  if ((peer = gst_pad_get_peer (id3demux->sinkpad)) == NULL)
+    return FALSE;
+
+  if (!gst_pad_query (peer, query)) {
+    gst_object_unref (peer);
+    return FALSE;
+  }
+
+  gst_object_unref (peer);
+
+  switch (GST_QUERY_TYPE (query)) {
+    case GST_QUERY_POSITION:
+    {
+      gst_query_parse_position (query, &format, &result);
+      if (format == GST_FORMAT_BYTES) {
+        result -= id3demux->strip_start;
+        gst_query_set_position (query, format, result);
+      }
+      break;
+    }
+    case GST_QUERY_DURATION:
+    {
+      gst_query_parse_duration (query, &format, &result);
+      if (format == GST_FORMAT_BYTES) {
+        result -= id3demux->strip_start + id3demux->strip_end;
+        gst_query_set_duration (query, format, result);
+      }
+      break;
+    }
+    default:
+      break;
+  }
+
+  return TRUE;
+}
+
+static const GstQueryType *
+gst_id3demux_get_query_types (GstPad * pad)
+{
+  static const GstQueryType types[] = {
+    GST_QUERY_POSITION,
+    GST_QUERY_DURATION,
+    0
+  };
+
+  return types;
+}
+
+typedef struct
+{
+  guint best_probability;
+  GstCaps *caps;
+  GstBuffer *buffer;
+}
+
+SimpleTypeFind;
+guint8 *
+simple_find_peek (gpointer data, gint64 offset, guint size)
+{
+  SimpleTypeFind *find = (SimpleTypeFind *) data;
+
+  if (offset < 0)
+    return NULL;
+
+  if (GST_BUFFER_SIZE (find->buffer) >= offset + size) {
+    return GST_BUFFER_DATA (find->buffer) + offset;
+  }
+  return NULL;
+}
+static void
+simple_find_suggest (gpointer data, guint probability, const GstCaps * caps)
+{
+  SimpleTypeFind *find = (SimpleTypeFind *) data;
+
+  if (probability > find->best_probability) {
+    GstCaps *copy = gst_caps_copy (caps);
+
+    gst_caps_replace (&find->caps, copy);
+    gst_caps_unref (copy);
+    find->best_probability = probability;
+  }
+}
+
+static GstCaps *
+gst_id3demux_do_typefind (GstID3Demux * id3demux, GstBuffer * buffer)
+{
+  GList *walk, *type_list;
+  SimpleTypeFind find;
+  GstTypeFind gst_find;
+
+  walk = type_list = gst_type_find_factory_get_list ();
+
+  find.buffer = buffer;
+  find.best_probability = 0;
+  find.caps = NULL;
+  gst_find.data = &find;
+  gst_find.peek = simple_find_peek;
+  gst_find.get_length = NULL;
+  gst_find.suggest = simple_find_suggest;
+  while (walk) {
+    GstTypeFindFactory *factory = GST_TYPE_FIND_FACTORY (walk->data);
+
+    gst_type_find_factory_call_function (factory, &gst_find);
+    if (find.best_probability >= GST_TYPE_FIND_MAXIMUM)
+      break;
+    walk = g_list_next (walk);
+  }
+  gst_plugin_feature_list_free (type_list);
+  if (find.best_probability > 0) {
+    GST_DEBUG ("Found caps %" GST_PTR_FORMAT " with buf size %u", find.caps,
+        GST_BUFFER_SIZE (buffer));
+    return find.caps;
+  }
+
+  return NULL;
+}
+
+static void
+gst_id3demux_send_tag_event (GstID3Demux * id3demux)
+{
+  /* FIXME: what's the correct merge mode? Docs need to tell... */
+  GstTagList *merged = gst_tag_list_merge (id3demux->event_tags,
+      id3demux->parsed_tags, GST_TAG_MERGE_KEEP);
+
+  if (id3demux->parsed_tags)
+    gst_element_post_message (GST_ELEMENT (id3demux),
+        gst_message_new_tag (GST_OBJECT (id3demux),
+            gst_tag_list_copy (id3demux->parsed_tags)));
+
+  if (merged) {
+    GstEvent *event = gst_event_new_tag (merged);
+
+    GST_EVENT_TIMESTAMP (event) = 0;
+    GST_DEBUG_OBJECT (id3demux, "Sending tag event on src pad");
+    gst_pad_push_event (id3demux->srcpad, event);
+  }
+}
+
+static gboolean
+plugin_init (GstPlugin * plugin)
+{
+  GST_DEBUG_CATEGORY_INIT (id3demux_debug, "id3demux", 0,
+      "GStreamer ID3 tag demuxer");
+
+  return gst_element_register (plugin, "id3demux",
+      GST_RANK_PRIMARY, GST_TYPE_ID3DEMUX);
+}
+
+GST_PLUGIN_DEFINE (GST_VERSION_MAJOR,
+    GST_VERSION_MINOR,
+    "id3demux",
+    "Demux ID3v1 and ID3v2 tags from a file",
+    plugin_init, VERSION, GST_LICENSE, GST_PACKAGE_NAME, GST_PACKAGE_ORIGIN)