1 files changed, 1526 insertions, 0 deletions

diff --git a/src/plugins/gstreamer_extractor.c b/src/plugins/gstreamer_extractor.c
new file mode 100644
index 0000000..81f2d5b
--- /dev/null
+++ b/src/plugins/gstreamer_extractor.c
@@ -0,0 +1,1526 @@
+/*
+     This file is part of libextractor.
+     (C) 2002, 2003, 2004, 2009, 2012 Vidyut Samanta and Christian Grothoff
+
+     libextractor is free software; you can redistribute it and/or modify
+     it under the terms of the GNU General Public License as published
+     by the Free Software Foundation; either version 3, or (at your
+     option) any later version.
+
+     libextractor 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
+     General Public License for more details.
+
+     You should have received a copy of the GNU General Public License
+     along with libextractor; see the file COPYING.  If not, write to the
+     Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+     Boston, MA 02111-1307, USA.
+ */
+/**
+ * @file plugins/gstreamer_extractor.c
+ * @brief extracts metadata from files using GStreamer
+ * @author LRN
+ */
+#include "platform.h"
+#include "extractor.h"
+
+#include <glib.h>
+#include <glib-object.h>
+#include <gst/pbutils/pbutils.h>
+#include <gst/tag/tag.h>
+
+struct KnownTag
+{
+  const char *gst_tag_id;
+  enum EXTRACTOR_MetaType le_type;
+};
+
+struct KnownTag __known_tags[] =
+{
+/**
+ * GST_TAG_TITLE:
+ *
+ * commonly used title (string)
+ *
+ * The title as it should be displayed, e.g. 'The Doll House'
+ */
+  {GST_TAG_TITLE, EXTRACTOR_METATYPE_TITLE},
+/**
+ * GST_TAG_TITLE_SORTNAME:
+ *
+ * commonly used title, as used for sorting (string)
+ *
+ * The title as it should be sorted, e.g. 'Doll House, The'
+ */
+  {GST_TAG_TITLE_SORTNAME, EXTRACTOR_METATYPE_TITLE},
+/**
+ * GST_TAG_ARTIST:
+ *
+ * person(s) responsible for the recording (string)
+ *
+ * The artist name as it should be displayed, e.g. 'Jimi Hendrix' or
+ * 'The Guitar Heroes'
+ */
+  {GST_TAG_ARTIST, EXTRACTOR_METATYPE_ARTIST},
+/**
+ * GST_TAG_ARTIST_SORTNAME:
+ *
+ * person(s) responsible for the recording, as used for sorting (string)
+ *
+ * The artist name as it should be sorted, e.g. 'Hendrix, Jimi' or
+ * 'Guitar Heroes, The'
+ */
+  {GST_TAG_ARTIST_SORTNAME, EXTRACTOR_METATYPE_ARTIST},
+/**
+ * GST_TAG_ALBUM:
+ *
+ * album containing this data (string)
+ *
+ * The album name as it should be displayed, e.g. 'The Jazz Guitar'
+ */
+  {GST_TAG_ALBUM, EXTRACTOR_METATYPE_ALBUM},
+/**
+ * GST_TAG_ALBUM_SORTNAME:
+ *
+ * album containing this data, as used for sorting (string)
+ *
+ * The album name as it should be sorted, e.g. 'Jazz Guitar, The'
+ */
+  {GST_TAG_ALBUM_SORTNAME, EXTRACTOR_METATYPE_ALBUM},
+/**
+ * GST_TAG_ALBUM_ARTIST:
+ *
+ * The artist of the entire album, as it should be displayed.
+ */
+  {GST_TAG_ALBUM_ARTIST, EXTRACTOR_METATYPE_ARTIST},
+/**
+ * GST_TAG_ALBUM_ARTIST_SORTNAME:
+ *
+ * The artist of the entire album, as it should be sorted.
+ */
+  {GST_TAG_ALBUM_ARTIST_SORTNAME, EXTRACTOR_METATYPE_ARTIST},
+/**
+ * GST_TAG_COMPOSER:
+ *
+ * person(s) who composed the recording (string)
+ */
+  {GST_TAG_COMPOSER, EXTRACTOR_METATYPE_COMPOSER},
+/**
+ * GST_TAG_DATE:
+ *
+ * date the data was created (#GDate structure)
+ */
+  {GST_TAG_DATE, EXTRACTOR_METATYPE_CREATION_TIME},
+/**
+ * GST_TAG_DATE_TIME:
+ *
+ * date and time the data was created (#GstDateTime structure)
+ */
+  {GST_TAG_DATE_TIME, EXTRACTOR_METATYPE_CREATION_TIME},
+/**
+ * GST_TAG_GENRE:
+ *
+ * genre this data belongs to (string)
+ */
+  {GST_TAG_GENRE, EXTRACTOR_METATYPE_GENRE},
+/**
+ * GST_TAG_COMMENT:
+ *
+ * free text commenting the data (string)
+ */
+  {GST_TAG_COMMENT, EXTRACTOR_METATYPE_COMMENT},
+/**
+ * GST_TAG_EXTENDED_COMMENT:
+ *
+ * key/value text commenting the data (string)
+ *
+ * Must be in the form of 'key=comment' or
+ * 'key[lc]=comment' where 'lc' is an ISO-639
+ * language code.
+ *
+ * This tag is used for unknown Vorbis comment tags,
+ * unknown APE tags and certain ID3v2 comment fields.
+ */
+  {GST_TAG_EXTENDED_COMMENT, EXTRACTOR_METATYPE_UNKNOWN},
+/**
+ * GST_TAG_TRACK_NUMBER:
+ *
+ * track number inside a collection (unsigned integer)
+ */
+  {GST_TAG_TRACK_NUMBER, EXTRACTOR_METATYPE_TRACK_NUMBER},
+/**
+ * GST_TAG_TRACK_COUNT:
+ *
+ * count of tracks inside collection this track belongs to (unsigned integer)
+ */
+  {GST_TAG_TRACK_COUNT, EXTRACTOR_METATYPE_SONG_COUNT},
+/**
+ * GST_TAG_ALBUM_VOLUME_NUMBER:
+ *
+ * disc number inside a collection (unsigned integer)
+ */
+  {GST_TAG_ALBUM_VOLUME_NUMBER, EXTRACTOR_METATYPE_DISC_NUMBER},
+/**
+ * GST_TAG_ALBUM_VOLUME_COUNT:
+ *
+ * count of discs inside collection this disc belongs to (unsigned integer)
+ */
+  {GST_TAG_ALBUM_VOLUME_NUMBER, EXTRACTOR_METATYPE_DISC_COUNT}, /* New! */
+/**
+ * GST_TAG_LOCATION:
+ *
+ * Origin of media as a URI (location, where the original of the file or stream
+ * is hosted) (string)
+ */
+  {GST_TAG_LOCATION, EXTRACTOR_METATYPE_URL},
+/**
+ * GST_TAG_HOMEPAGE:
+ *
+ * Homepage for this media (i.e. artist or movie homepage) (string)
+ */
+  {GST_TAG_HOMEPAGE, EXTRACTOR_METATYPE_URL},
+/**
+ * GST_TAG_DESCRIPTION:
+ *
+ * short text describing the content of the data (string)
+ */
+  {GST_TAG_DESCRIPTION, EXTRACTOR_METATYPE_DESCRIPTION},
+/**
+ * GST_TAG_VERSION:
+ *
+ * version of this data (string)
+ */
+  {GST_TAG_VERSION, EXTRACTOR_METATYPE_PRODUCT_VERSION},
+/**
+ * GST_TAG_ISRC:
+ *
+ * International Standard Recording Code - see http://www.ifpi.org/isrc/ (string)
+ */
+  {GST_TAG_ISRC, EXTRACTOR_METATYPE_ISRC},
+/**
+ * GST_TAG_ORGANIZATION:
+ *
+ * organization (string)
+ */
+  {GST_TAG_ORGANIZATION, EXTRACTOR_METATYPE_COMPANY},
+/**
+ * GST_TAG_COPYRIGHT:
+ *
+ * copyright notice of the data (string)
+ */
+  {GST_TAG_COPYRIGHT, EXTRACTOR_METATYPE_COPYRIGHT},
+/**
+ * GST_TAG_COPYRIGHT_URI:
+ *
+ * URI to location where copyright details can be found (string)
+ */
+  {GST_TAG_COPYRIGHT_URI, EXTRACTOR_METATYPE_COPYRIGHT},
+/**
+ * GST_TAG_ENCODED_BY:
+ *
+ * name of the person or organisation that encoded the file. May contain a
+ * copyright message if the person or organisation also holds the copyright
+ * (string)
+ *
+ * Note: do not use this field to describe the encoding application. Use
+ * #GST_TAG_APPLICATION_NAME or #GST_TAG_COMMENT for that.
+ */
+  {GST_TAG_ENCODED_BY, EXTRACTOR_METATYPE_ENCODED_BY},
+/**
+ * GST_TAG_CONTACT:
+ *
+ * contact information (string)
+ */
+  {GST_TAG_CONTACT, EXTRACTOR_METATYPE_CONTACT_INFORMATION},
+/**
+ * GST_TAG_LICENSE:
+ *
+ * license of data (string)
+ */
+  {GST_TAG_LICENSE, EXTRACTOR_METATYPE_LICENSE},
+/**
+ * GST_TAG_LICENSE_URI:
+ *
+ * URI to location where license details can be found (string)
+ */
+  {GST_TAG_LICENSE_URI, EXTRACTOR_METATYPE_LICENSE},
+/**
+ * GST_TAG_PERFORMER:
+ *
+ * person(s) performing (string)
+ */
+  {GST_TAG_PERFORMER, EXTRACTOR_METATYPE_PERFORMER},
+/**
+ * GST_TAG_DURATION:
+ *
+ * length in GStreamer time units (nanoseconds) (unsigned 64-bit integer)
+ */
+  {GST_TAG_DURATION, EXTRACTOR_METATYPE_DURATION},
+/**
+ * GST_TAG_CODEC:
+ *
+ * codec the data is stored in (string)
+ */
+  {GST_TAG_CODEC, EXTRACTOR_METATYPE_CODEC}, /* New! */
+/**
+ * GST_TAG_VIDEO_CODEC:
+ *
+ * codec the video data is stored in (string)
+ */
+  {GST_TAG_VIDEO_CODEC, EXTRACTOR_METATYPE_VIDEO_CODEC}, /* New! */
+/**
+ * GST_TAG_AUDIO_CODEC:
+ *
+ * codec the audio data is stored in (string)
+ */
+  {GST_TAG_AUDIO_CODEC, EXTRACTOR_METATYPE_AUDIO_CODEC}, /* New! */
+/**
+ * GST_TAG_SUBTITLE_CODEC:
+ *
+ * codec/format the subtitle data is stored in (string)
+ */
+  {GST_TAG_SUBTITLE_CODEC, EXTRACTOR_METATYPE_SUBTITLE_CODEC}, /* New! */
+/**
+ * GST_TAG_CONTAINER_FORMAT:
+ *
+ * container format the data is stored in (string)
+ */
+  {GST_TAG_CONTAINER_FORMAT, EXTRACTOR_METATYPE_CONTAINER_FORMAT}, /* New! */
+/**
+ * GST_TAG_BITRATE:
+ *
+ * exact or average bitrate in bits/s (unsigned integer)
+ */
+  {GST_TAG_BITRATE, EXTRACTOR_METATYPE_BITRATE}, /* New! */
+/**
+ * GST_TAG_NOMINAL_BITRATE:
+ *
+ * nominal bitrate in bits/s (unsigned integer). The actual bitrate might be
+ * different from this target bitrate.
+ */
+  {GST_TAG_NOMINAL_BITRATE, EXTRACTOR_METATYPE_NOMINAL_BITRATE}, /* New! */
+/**
+ * GST_TAG_MINIMUM_BITRATE:
+ *
+ * minimum bitrate in bits/s (unsigned integer)
+ */
+  {GST_TAG_MINIMUM_BITRATE, EXTRACTOR_METATYPE_MINIMUM_BITRATE}, /* New! */
+/**
+ * GST_TAG_MAXIMUM_BITRATE:
+ *
+ * maximum bitrate in bits/s (unsigned integer)
+ */
+  {GST_TAG_MAXIMUM_BITRATE, EXTRACTOR_METATYPE_MAXIMUM_BITRATE}, /* New! */
+/**
+ * GST_TAG_SERIAL:
+ *
+ * serial number of track (unsigned integer)
+ */
+  {GST_TAG_SERIAL, EXTRACTOR_METATYPE_SERIAL}, /* New! */
+/**
+ * GST_TAG_ENCODER:
+ *
+ * encoder used to encode this stream (string)
+ */
+  {GST_TAG_ENCODER, EXTRACTOR_METATYPE_ENCODER}, /* New */
+/**
+ * GST_TAG_ENCODER_VERSION:
+ *
+ * version of the encoder used to encode this stream (unsigned integer)
+ */
+  {GST_TAG_ENCODER_VERSION, EXTRACTOR_METATYPE_ENCODER_VERSION}, /* New! */
+/**
+ * GST_TAG_TRACK_GAIN:
+ *
+ * track gain in db (double)
+ */
+  {GST_TAG_TRACK_GAIN, EXTRACTOR_METATYPE_TRACK_GAIN}, /* New! */
+/**
+ * GST_TAG_TRACK_PEAK:
+ *
+ * peak of the track (double)
+ */
+  {GST_TAG_TRACK_PEAK, EXTRACTOR_METATYPE_TRACK_PEAK}, /* New! */
+/**
+ * GST_TAG_ALBUM_GAIN:
+ *
+ * album gain in db (double)
+ */
+  {GST_TAG_ALBUM_GAIN, EXTRACTOR_METATYPE_ALBUM_GAIN}, /* New! */
+/**
+ * GST_TAG_ALBUM_PEAK:
+ *
+ * peak of the album (double)
+ */
+  {GST_TAG_ALBUM_PEAK, EXTRACTOR_METATYPE_ALBUM_PEAK}, /* New! */
+/**
+ * GST_TAG_REFERENCE_LEVEL:
+ *
+ * reference level of track and album gain values (double)
+ */
+  {GST_TAG_REFERENCE_LEVEL, EXTRACTOR_METATYPE_REFERENCE_LEVEL}, /* New! */
+/**
+ * GST_TAG_LANGUAGE_CODE:
+ *
+ * ISO-639-2 or ISO-639-1 code for the language the content is in (string)
+ *
+ * There is utility API in libgsttag in gst-plugins-base to obtain a translated
+ * language name from the language code: gst_tag_get_language_name()
+ */
+  {GST_TAG_LANGUAGE_CODE, EXTRACTOR_METATYPE_LANGUAGE},
+/**
+ * GST_TAG_LANGUAGE_NAME:
+ *
+ * Name of the language the content is in (string)
+ *
+ * Free-form name of the language the content is in, if a language code
+ * is not available. This tag should not be set in addition to a language
+ * code. It is undefined what language or locale the language name is in.
+ */
+  {GST_TAG_LANGUAGE_NAME, EXTRACTOR_METATYPE_LANGUAGE},
+/**
+ * GST_TAG_IMAGE:
+ *
+ * image (sample) (sample taglist should specify the content type and preferably
+ * also set "image-type" field as #GstTagImageType)
+ */
+  {GST_TAG_IMAGE, EXTRACTOR_METATYPE_PICTURE},
+/**
+ * GST_TAG_PREVIEW_IMAGE:
+ *
+ * image that is meant for preview purposes, e.g. small icon-sized version
+ * (sample) (sample taglist should specify the content type)
+ */
+  {GST_TAG_IMAGE, EXTRACTOR_METATYPE_THUMBNAIL},
+/**
+ * GST_TAG_ATTACHMENT:
+ *
+ * generic file attachment (sample) (sample taglist should specify the content
+ * type and if possible set "filename" to the file name of the
+ * attachment)
+ */
+  /* No equivalent, and none needed? */
+/**
+ * GST_TAG_BEATS_PER_MINUTE:
+ *
+ * number of beats per minute in audio (double)
+ */
+  {GST_TAG_BEATS_PER_MINUTE, EXTRACTOR_METATYPE_BEATS_PER_MINUTE},
+/**
+ * GST_TAG_KEYWORDS:
+ *
+ * comma separated keywords describing the content (string).
+ */
+  {GST_TAG_KEYWORDS, EXTRACTOR_METATYPE_KEYWORDS},
+/**
+ * GST_TAG_GEO_LOCATION_NAME:
+ *
+ * human readable descriptive location of where the media has been recorded or
+ * produced. (string).
+ */
+  {GST_TAG_GEO_LOCATION_NAME, EXTRACTOR_METATYPE_LOCATION_NAME}, /* New! */
+/**
+ * GST_TAG_GEO_LOCATION_LATITUDE:
+ *
+ * geo latitude location of where the media has been recorded or produced in
+ * degrees according to WGS84 (zero at the equator, negative values for southern
+ * latitudes) (double).
+ */
+  {GST_TAG_GEO_LOCATION_LATITUDE, EXTRACTOR_METATYPE_GPS_LATITUDE},
+/**
+ * GST_TAG_GEO_LOCATION_LONGITUDE:
+ *
+ * geo longitude location of where the media has been recorded or produced in
+ * degrees according to WGS84 (zero at the prime meridian in Greenwich/UK,
+ * negative values for western longitudes). (double).
+ */
+  {GST_TAG_GEO_LOCATION_LONGITUDE, EXTRACTOR_METATYPE_GPS_LONGITUDE},
+/**
+ * GST_TAG_GEO_LOCATION_ELEVATION:
+ *
+ * geo elevation of where the media has been recorded or produced in meters
+ * according to WGS84 (zero is average sea level) (double).
+ */
+  {GST_TAG_GEO_LOCATION_ELEVATION, EXTRACTOR_METATYPE_LOCATION_ELEVATION}, /* New! */
+/**
+ * GST_TAG_GEO_LOCATION_COUNTRY:
+ *
+ * The country (english name) where the media has been produced (string).
+ */
+  {GST_TAG_GEO_LOCATION_COUNTRY, EXTRACTOR_METATYPE_LOCATION_COUNTRY},
+/**
+ * GST_TAG_GEO_LOCATION_CITY:
+ *
+ * The city (english name) where the media has been produced (string).
+ */
+  {GST_TAG_GEO_LOCATION_CITY, EXTRACTOR_METATYPE_LOCATION_CITY},
+/**
+ * GST_TAG_GEO_LOCATION_SUBLOCATION:
+ *
+ * A location 'smaller' than GST_TAG_GEO_LOCATION_CITY that specifies better
+ * where the media has been produced. (e.g. the neighborhood) (string).
+ *
+ * This tag has been added as this is how it is handled/named in XMP's
+ * Iptc4xmpcore schema.
+ */
+  {GST_TAG_GEO_LOCATION_SUBLOCATION, EXTRACTOR_METATYPE_LOCATION_SUBLOCATION},
+/**
+ * GST_TAG_GEO_LOCATION_HORIZONTAL_ERROR:
+ *
+ * Represents the expected error on the horizontal positioning in
+ * meters (double).
+ */
+  {GST_TAG_GEO_LOCATION_HORIZONTAL_ERROR, EXTRACTOR_METATYPE_LOCATION_HORIZONTAL_ERROR}, /* New! */
+/**
+ * GST_TAG_GEO_LOCATION_MOVEMENT_SPEED:
+ *
+ * Speed of the capturing device when performing the capture.
+ * Represented in m/s. (double)
+ *
+ * See also #GST_TAG_GEO_LOCATION_MOVEMENT_DIRECTION
+ */
+  {GST_TAG_GEO_LOCATION_MOVEMENT_SPEED, EXTRACTOR_METATYPE_LOCATION_MOVEMENT_SPEED}, /* New! */
+/**
+ * GST_TAG_GEO_LOCATION_MOVEMENT_DIRECTION:
+ *
+ * Indicates the movement direction of the device performing the capture
+ * of a media. It is represented as degrees in floating point representation,
+ * 0 means the geographic north, and increases clockwise (double from 0 to 360)
+ *
+ * See also #GST_TAG_GEO_LOCATION_CAPTURE_DIRECTION
+ */
+  {GST_TAG_GEO_LOCATION_MOVEMENT_DIRECTION, EXTRACTOR_METATYPE_LOCATION_MOVEMENT_DIRECTION}, /* New! */
+/**
+ * GST_TAG_GEO_LOCATION_CAPTURE_DIRECTION:
+ *
+ * Indicates the direction the device is pointing to when capturing
+ * a media. It is represented as degrees in floating point representation,
+ * 0 means the geographic north, and increases clockwise (double from 0 to 360)
+ *
+ * See also #GST_TAG_GEO_LOCATION_MOVEMENT_DIRECTION
+ */
+  {GST_TAG_GEO_LOCATION_CAPTURE_DIRECTION, EXTRACTOR_METATYPE_LOCATION_CAPTURE_DIRECTION}, /* New! */
+/**
+ * GST_TAG_SHOW_NAME:
+ *
+ * Name of the show, used for displaying (string)
+ */
+  {GST_TAG_SHOW_NAME, EXTRACTOR_METATYPE_SHOW_NAME},
+/**
+ * GST_TAG_SHOW_SORTNAME:
+ *
+ * Name of the show, used for sorting (string)
+ */
+  {GST_TAG_SHOW_SORTNAME, EXTRACTOR_METATYPE_SHOW_NAME},
+/**
+ * GST_TAG_SHOW_EPISODE_NUMBER:
+ *
+ * Number of the episode within a season/show (unsigned integer)
+ */
+  {GST_TAG_SHOW_EPISODE_NUMBER, EXTRACTOR_METATYPE_SHOW_EPISODE_NUMBER}, /* New! */
+/**
+ * GST_TAG_SHOW_SEASON_NUMBER:
+ *
+ * Number of the season of a show/series (unsigned integer)
+ */
+  {GST_TAG_SHOW_SEASON_NUMBER, EXTRACTOR_METATYPE_SHOW_SEASON_NUMBER}, /* New! */
+/**
+ * GST_TAG_LYRICS:
+ *
+ * The lyrics of the media (string)
+ */
+  {GST_TAG_LYRICS, EXTRACTOR_METATYPE_LYRICS},
+/**
+ * GST_TAG_COMPOSER_SORTNAME:
+ *
+ * The composer's name, used for sorting (string)
+ */
+  {GST_TAG_COMPOSER_SORTNAME, EXTRACTOR_METATYPE_COMPOSER},
+/**
+ * GST_TAG_GROUPING:
+ *
+ * Groups together media that are related and spans multiple tracks. An
+ * example are multiple pieces of a concerto. (string)
+ */
+  {GST_TAG_GROUPING, EXTRACTOR_METATYPE_GROUPING}, /* New! */
+/**
+ * GST_TAG_USER_RATING:
+ *
+ * Rating attributed by a person (likely the application user).
+ * The higher the value, the more the user likes this media
+ * (unsigned int from 0 to 100)
+ */
+  {GST_TAG_USER_RATING, EXTRACTOR_METATYPE_POPULARITY_METER},
+/**
+ * GST_TAG_DEVICE_MANUFACTURER:
+ *
+ * Manufacturer of the device used to create the media (string)
+ */
+  {GST_TAG_DEVICE_MANUFACTURER, EXTRACTOR_METATYPE_DEVICE_MANUFACTURER}, /* New! */
+/**
+ * GST_TAG_DEVICE_MODEL:
+ *
+ * Model of the device used to create the media (string)
+ */
+  {GST_TAG_DEVICE_MODEL, EXTRACTOR_METATYPE_DEVICE_MODEL}, /* New! */
+/**
+ * GST_TAG_APPLICATION_NAME:
+ *
+ * Name of the application used to create the media (string)
+ */
+  {GST_TAG_APPLICATION_NAME, EXTRACTOR_METATYPE_CREATED_BY_SOFTWARE},
+/**
+ * GST_TAG_APPLICATION_DATA:
+ *
+ * Arbitrary application data (sample)
+ *
+ * Some formats allow applications to add their own arbitrary data
+ * into files. This data is application dependent.
+ */
+  /* No equivalent, and none needed (not really metadata)? */
+/**
+ * GST_TAG_IMAGE_ORIENTATION:
+ *
+ * Represents the 'Orientation' tag from EXIF. Defines how the image
+ * should be rotated and mirrored for display. (string)
+ *
+ * This tag has a predefined set of allowed values:
+ *   "rotate-0"
+ *   "rotate-90"
+ *   "rotate-180"
+ *   "rotate-270"
+ *   "flip-rotate-0"
+ *   "flip-rotate-90"
+ *   "flip-rotate-180"
+ *   "flip-rotate-270"
+ *
+ * The naming is adopted according to a possible transformation to perform
+ * on the image to fix its orientation, obviously equivalent operations will
+ * yield the same result.
+ *
+ * Rotations indicated by the values are in clockwise direction and
+ * 'flip' means an horizontal mirroring.
+ */
+  {GST_TAG_IMAGE_ORIENTATION, EXTRACTOR_METATYPE_ORIENTATION}
+};
+
+enum CurrentStreamType
+{
+  STREAM_TYPE_NONE = 0,
+  STREAM_TYPE_AUDIO = 1,
+  STREAM_TYPE_VIDEO = 2,
+  STREAM_TYPE_SUBTITLE = 3,
+  STREAM_TYPE_CONTAINER = 4
+};
+
+typedef struct
+{
+  GMainLoop *loop;
+  GstDiscoverer *dc;
+  GstElement *source;
+  struct EXTRACTOR_ExtractContext *ec;
+  long length;
+  long offset;
+  long toc_depth;
+  size_t toc_length;
+  size_t toc_pos;
+  gchar *toc;
+  gboolean toc_print_phase;
+  unsigned char time_to_leave;
+  enum CurrentStreamType st;
+} PrivStruct;
+
+static void send_streams (GstDiscovererStreamInfo *info, PrivStruct *ps);
+
+static void send_tag_foreach (const GstTagList * tags, const gchar * tag,
+    gpointer user_data);
+
+static void send_discovered_info (GstDiscovererInfo * info, PrivStruct * ps);
+
+static void _source_setup (GstDiscoverer * dc, GstElement * source, PrivStruct * ps);
+
+static void feed_data (GstElement * appsrc, guint size, PrivStruct * ps);
+static gboolean seek_data (GstElement * appsrc, guint64 position, PrivStruct * ps);
+
+static int initialized = FALSE;
+
+static GstDiscoverer *dc;
+static PrivStruct *ps;
+
+static void
+_new_discovered_uri (GstDiscoverer * dc, GstDiscovererInfo * info, GError * err, PrivStruct * ps)
+{
+  send_discovered_info (info, ps);
+}
+
+static void
+_discoverer_finished (GstDiscoverer * dc, PrivStruct * ps)
+{
+  g_main_loop_quit (ps->loop);
+}
+
+static int
+initialize ()
+{
+  gint timeout = 10;
+  GError *err = NULL;
+
+  gst_init (NULL, NULL);
+
+  dc = gst_discoverer_new (timeout * GST_SECOND, &err);
+  if (G_UNLIKELY (dc == NULL)) {
+    g_print ("Error initializing: %s\n", err->message);
+    return FALSE;
+  }
+
+  ps = g_new0 (PrivStruct, 1);
+
+  ps->dc = dc;
+  ps->loop = g_main_loop_new (NULL, TRUE);
+
+  /* connect signals */
+  g_signal_connect (dc, "discovered", G_CALLBACK (_new_discovered_uri), ps);
+  g_signal_connect (dc, "finished", G_CALLBACK (_discoverer_finished), ps);
+  g_signal_connect (dc, "source-setup", G_CALLBACK (_source_setup), ps);
+
+  return TRUE;
+}
+
+/* this callback is called when discoverer has constructed a source object to
+ * read from. Since we provided the appsrc:// uri to discoverer, this will be
+ * the appsrc that we must handle. We set up some signals - one to push data
+ * into appsrc and one to perform a seek. */
+static void
+_source_setup (GstDiscoverer * dc, GstElement * source, PrivStruct * ps)
+{
+  if (ps->source)
+    gst_object_unref (GST_OBJECT (ps->source));
+  ps->source = source;
+  gst_object_ref (source);
+
+  /* we can set the length in appsrc. This allows some elements to estimate the
+   * total duration of the stream. It's a good idea to set the property when you
+   * can but it's not required. */
+  if (ps->length > 0)
+  {
+    g_object_set (ps->source, "size", (gint64) ps->length, NULL);
+    gst_util_set_object_arg (G_OBJECT (ps->source), "stream-type", "random-access");
+  }
+  else
+    gst_util_set_object_arg (G_OBJECT (ps->source), "stream-type", "seekable");
+
+  /* configure the appsrc, we will push a buffer to appsrc when it needs more
+   * data */
+  g_signal_connect (ps->source, "need-data", G_CALLBACK (feed_data), ps);
+  g_signal_connect (ps->source, "seek-data", G_CALLBACK (seek_data), ps);
+}
+
+static void
+feed_data (GstElement * appsrc, guint size, PrivStruct * ps)
+{
+  GstBuffer *buffer;
+  GstFlowReturn ret;
+  GstMemory *data;
+  GstMapInfo mi;
+  long data_len;
+  int eos = FALSE;
+
+  if (ps->length > 0 && ps->offset >= ps->length) {
+    /* we are at the EOS, send end-of-stream */
+    g_signal_emit_by_name (ps->source, "end-of-stream", &ret);
+    return;
+  }
+
+  buffer = gst_buffer_new ();
+  
+  if (ps->length > 0 && ps->offset + size > ps->length)
+    size = ps->length - ps->offset;
+
+  data = gst_allocator_alloc (NULL, size, NULL);
+  eos = TRUE;
+  if (gst_memory_map (data, &mi, GST_MAP_WRITE | GST_MAP_READ))
+  {
+    uint8_t *le_data;
+    data_len = ps->ec->read (ps->ec->cls, (void **) &le_data, size);
+    if (data_len > 0)
+      memcpy (mi.data, le_data, data_len);
+    gst_memory_unmap (data, &mi);
+    if (data_len > 0)
+    {
+      gst_memory_resize (data, 0, data_len);
+      gst_buffer_append_memory (buffer, data);
+
+      /* we need to set an offset for random access */
+      GST_BUFFER_OFFSET (buffer) = ps->offset;
+      GST_BUFFER_OFFSET_END (buffer) = ps->offset + data_len;
+
+      GST_DEBUG ("feed buffer %p, offset %" G_GUINT64_FORMAT "-%u", buffer,
+          ps->offset, data_len);
+      g_signal_emit_by_name (ps->source, "push-buffer", buffer, &ret);
+      eos = FALSE;
+    }
+  }
+
+  if (eos)
+  {
+    g_signal_emit_by_name (ps->source, "end-of-stream", &ret);
+    gst_memory_unref (data);
+  }
+
+  gst_buffer_unref (buffer);
+
+  ps->offset += data_len;
+
+  return;
+}
+
+static gboolean
+seek_data (GstElement * appsrc, guint64 position, PrivStruct * ps)
+{
+  GST_DEBUG ("seek to offset %" G_GUINT64_FORMAT, position);
+  ps->offset = ps->ec->seek (ps->ec->cls, position, SEEK_SET);
+
+  return ps->offset >= 0;
+}
+
+static gboolean
+_run_async (PrivStruct * ps)
+{
+  gst_discoverer_discover_uri_async (ps->dc, "appsrc://");
+  return FALSE;
+}
+
+/**
+ * This will be the main method of your plugin.
+ * Describe a bit what it does here.
+ *
+ * @param ec extraction context, here you get the API
+ *   for accessing the file data and for returning
+ *   meta data
+ */
+void
+EXTRACTOR_gstreamer_extract_method (struct EXTRACTOR_ExtractContext *ec)
+{
+  int64_t offset;
+  void *data;
+
+  if (!initialized)
+    if (! (initialized = initialize ()))
+      return;
+
+  ps->ec = ec;
+  ps->length = ps->ec->get_size (ps->ec->cls);
+  if (ps->length == UINT_MAX)
+    ps->length = 0;
+
+  gst_discoverer_start (dc);
+
+  g_idle_add ((GSourceFunc) _run_async, ps);
+
+  g_main_loop_run (ps->loop);
+
+  gst_discoverer_stop (dc);
+
+  /* initialize state here */
+  
+  /* Call seek (plugin, POSITION, WHENCE) to seek (if you know where
+   * data starts):
+   */
+  // ec->seek (ec->cls, POSITION, SEEK_SET);
+
+  /* Call read (plugin, &data, COUNT) to read COUNT bytes 
+   */
+
+
+  /* Once you find something, call proc(). If it returns non-0 - you're done.
+   */
+  // if (0 != ec->proc (ec->cls, ...)) return;
+
+  /* Don't forget to free anything you've allocated before returning! */
+  return;
+}
+
+static gboolean

+send_structure_foreach (GQuark field_id, const GValue *value,
+    gpointer user_data)
+{
+  PrivStruct *ps = (PrivStruct *) user_data;
+  gchar *str;
+  const char *field_name = g_quark_to_string (field_id);
+
+  /* TODO: check a list of known quarks, use specific EXTRACTOR_MetaType  */
+  switch (G_VALUE_TYPE (value))
+  {
+  case G_TYPE_STRING:
+    str = g_value_dup_string (value);
+    break;
+  case G_TYPE_UINT:
+  case G_TYPE_DOUBLE:
+  default:
+    str = gst_value_serialize (value);
+  }
+  if (str != NULL)
+  {
+    gchar *senddata = g_strdup_printf ("%s=%s", field_name, str);
+    ps->time_to_leave = ps->ec->proc (ps->ec->cls, "gstreamer",
+        EXTRACTOR_METATYPE_UNKNOWN, EXTRACTOR_METAFORMAT_UTF8, "text/plain",
+        (const char *) senddata, strlen (senddata) + 1);
+    g_free (senddata);
+  }
+
+  g_free (str);
+  
+  return !ps->time_to_leave;
+}
+
+static int
+send_audio_info (GstDiscovererAudioInfo *info, PrivStruct *ps)
+{
+  gchar *tmp;
+  const gchar *ctmp;
+  guint u;
+
+  ctmp = gst_discoverer_audio_info_get_language (info);
+  if (ctmp)
+    if (ps->time_to_leave = ps->ec->proc (ps->ec->cls, "gstreamer",
+        EXTRACTOR_METATYPE_AUDIO_LANGUAGE, EXTRACTOR_METAFORMAT_UTF8, "text/plain", /* New! */
+        (const char *) ctmp, strlen (ctmp) + 1))
+      return TRUE;
+
+  u = gst_discoverer_audio_info_get_channels (info);
+  if (u > 0)
+  {
+    tmp = g_strdup_printf ("%u", u);
+    ps->time_to_leave = ps->ec->proc (ps->ec->cls, "gstreamer",
+      EXTRACTOR_METATYPE_CHANNELS, EXTRACTOR_METAFORMAT_UTF8, "text/plain", /* New! */
+      (const char *) tmp, strlen (tmp) + 1);
+    g_free (tmp);
+    if (ps->time_to_leave)
+      return TRUE;
+  }
+
+  u = gst_discoverer_audio_info_get_sample_rate (info);
+  if (u > 0)
+  {
+    tmp = g_strdup_printf ("%u", u);
+    ps->time_to_leave = ps->ec->proc (ps->ec->cls, "gstreamer",
+      EXTRACTOR_METATYPE_SAMPLE_RATE, EXTRACTOR_METAFORMAT_UTF8, "text/plain", /* New! */
+      (const char *) tmp, strlen (tmp) + 1);
+    g_free (tmp);
+    if (ps->time_to_leave)
+      return TRUE;
+  }
+
+  u = gst_discoverer_audio_info_get_depth (info);
+  if (u > 0)
+  {
+    tmp = g_strdup_printf ("%u", u);
+    ps->time_to_leave = ps->ec->proc (ps->ec->cls, "gstreamer",
+      EXTRACTOR_METATYPE_AUDIO_DEPTH, EXTRACTOR_METAFORMAT_UTF8, "text/plain", /* New! */
+      (const char *) tmp, strlen (tmp) + 1);
+    g_free (tmp);
+    if (ps->time_to_leave)
+      return TRUE;
+  }
+
+  u = gst_discoverer_audio_info_get_bitrate (info);
+  if (u > 0)
+  {
+    tmp = g_strdup_printf ("%u", u);
+    ps->time_to_leave = ps->ec->proc (ps->ec->cls, "gstreamer",
+      EXTRACTOR_METATYPE_AUDIO_BITRATE, EXTRACTOR_METAFORMAT_UTF8, "text/plain", /* New! */
+      (const char *) tmp, strlen (tmp) + 1);
+    g_free (tmp);
+    if (ps->time_to_leave)
+      return TRUE;
+  }
+
+  u = gst_discoverer_audio_info_get_max_bitrate (info);
+  if (u > 0)
+  {
+    tmp = g_strdup_printf ("%u", u);
+    ps->time_to_leave = ps->ec->proc (ps->ec->cls, "gstreamer",
+      EXTRACTOR_METATYPE_MAXIMUM_AUDIO_BITRATE, EXTRACTOR_METAFORMAT_UTF8, "text/plain", /* New! */
+      (const char *) tmp, strlen (tmp) + 1);
+    g_free (tmp);
+    if (ps->time_to_leave)
+      return TRUE;
+  }
+
+  return FALSE;
+}
+
+static int
+send_video_info (GstDiscovererVideoInfo *info, PrivStruct *ps)
+{
+  gchar *tmp;
+  guint u, u2;
+
+  u = gst_discoverer_video_info_get_width (info);
+  u2 = gst_discoverer_video_info_get_height (info);
+  if (u > 0 && u2 > 0)
+  {
+    tmp = g_strdup_printf ("%ux%u", u, u2);
+    ps->time_to_leave = ps->ec->proc (ps->ec->cls, "gstreamer",
+      EXTRACTOR_METATYPE_VIDEO_DIMENSIONS, EXTRACTOR_METAFORMAT_UTF8, "text/plain", /* New! */
+      (const char *) tmp, strlen (tmp) + 1);
+    g_free (tmp);
+    if (ps->time_to_leave)
+      return TRUE;
+  }
+
+  u = gst_discoverer_video_info_get_depth (info);
+  if (u > 0)
+  {
+    tmp = g_strdup_printf ("%u", u);
+    ps->time_to_leave = ps->ec->proc (ps->ec->cls, "gstreamer",
+      EXTRACTOR_METATYPE_VIDEO_DEPTH, EXTRACTOR_METAFORMAT_UTF8, "text/plain", /* New! */
+      (const char *) tmp, strlen (tmp) + 1);
+    g_free (tmp);
+    if (ps->time_to_leave)
+      return TRUE;
+  }
+
+  u = gst_discoverer_video_info_get_framerate_num (info);
+  u2 = gst_discoverer_video_info_get_framerate_denom (info);
+  if (u > 0 && u2 > 0)
+  {
+    tmp = g_strdup_printf ("%u/%u", u, u2);
+    ps->time_to_leave = ps->ec->proc (ps->ec->cls, "gstreamer",
+      EXTRACTOR_METATYPE_FRAME_RATE, EXTRACTOR_METAFORMAT_UTF8, "text/plain", /* New! */
+      (const char *) tmp, strlen (tmp) + 1);
+    g_free (tmp);
+    if (ps->time_to_leave)
+      return TRUE;
+  }
+
+  u = gst_discoverer_video_info_get_par_num (info);
+  u2 = gst_discoverer_video_info_get_par_denom (info);
+  if (u > 0 && u2 > 0)
+  {
+    tmp = g_strdup_printf ("%u/%u", u, u2);
+    ps->time_to_leave = ps->ec->proc (ps->ec->cls, "gstreamer",
+      EXTRACTOR_METATYPE_PIXEL_ASPECT_RATIO, EXTRACTOR_METAFORMAT_UTF8, "text/plain", /* New! */
+      (const char *) tmp, strlen (tmp) + 1);
+    g_free (tmp);
+    if (ps->time_to_leave)
+      return TRUE;
+  }
+
+  /* gst_discoverer_video_info_is_interlaced (info) I don't trust it... */
+
+  u = gst_discoverer_video_info_get_bitrate (info);
+  if (u > 0 && u2 > 0)
+  {
+    tmp = g_strdup_printf ("%u", u);
+    ps->time_to_leave = ps->ec->proc (ps->ec->cls, "gstreamer",
+      EXTRACTOR_METATYPE_VIDEO_BITRATE, EXTRACTOR_METAFORMAT_UTF8, "text/plain", /* New! */
+      (const char *) tmp, strlen (tmp) + 1);
+    g_free (tmp);
+    if (ps->time_to_leave)
+      return TRUE;
+  }
+
+  u = gst_discoverer_video_info_get_max_bitrate (info);
+  if (u > 0 && u2 > 0)
+  {
+    tmp = g_strdup_printf ("%u", u);
+    ps->time_to_leave = ps->ec->proc (ps->ec->cls, "gstreamer",
+      EXTRACTOR_METATYPE_MAXIMUM_VIDEO_BITRATE, EXTRACTOR_METAFORMAT_UTF8, "text/plain", /* New! */
+      (const char *) tmp, strlen (tmp) + 1);
+    g_free (tmp);
+    if (ps->time_to_leave)
+      return TRUE;
+  }
+
+  return FALSE;
+}
+
+static int
+send_subtitle_info (GstDiscovererSubtitleInfo *info, PrivStruct *ps)
+{
+  gchar *tmp;
+  const gchar *ctmp;
+
+  ctmp = gst_discoverer_subtitle_info_get_language (info);
+  if (ctmp)
+    if (ps->time_to_leave = ps->ec->proc (ps->ec->cls, "gstreamer",
+        EXTRACTOR_METATYPE_SUBTITLE_LANGUAGE, EXTRACTOR_METAFORMAT_UTF8, "text/plain", /* New! */
+        (const char *) ctmp, strlen (ctmp) + 1))
+      return TRUE;
+
+  return FALSE;
+}
+
+static void
+send_stream_info (GstDiscovererStreamInfo * info, PrivStruct *ps)
+{
+  gchar *desc = NULL;
+  const GstStructure *misc;
+  GstCaps *caps;
+  const GstTagList *tags;
+
+  caps = gst_discoverer_stream_info_get_caps (info);
+
+  if (caps)
+  {
+    GstStructure *structure = gst_caps_get_structure (caps, 0);
+    const gchar *structname = gst_structure_get_name (structure);
+    ps->time_to_leave = ps->ec->proc (ps->ec->cls, "gstreamer",
+      EXTRACTOR_METATYPE_MIMETYPE, EXTRACTOR_METAFORMAT_UTF8, "text/plain",
+      (const char *) structname, strlen (structname) + 1);
+    if (!ps->time_to_leave)
+    {
+      gst_structure_foreach (structure, send_structure_foreach, ps);
+    }
+    gst_caps_unref (caps);
+  }
+
+  if (ps->time_to_leave)
+    return;
+
+  misc = gst_discoverer_stream_info_get_misc (info);
+  if (misc)
+  {
+    gst_structure_foreach (misc, send_structure_foreach, ps);
+  }
+
+  if (ps->time_to_leave)
+    return;
+
+  tags = gst_discoverer_stream_info_get_tags (info);
+  if (tags)
+  {
+    if (GST_IS_DISCOVERER_AUDIO_INFO (info))
+      ps->st = STREAM_TYPE_AUDIO;
+    else if (GST_IS_DISCOVERER_VIDEO_INFO (info))
+      ps->st = STREAM_TYPE_VIDEO;
+    else if (GST_IS_DISCOVERER_SUBTITLE_INFO (info))
+      ps->st = STREAM_TYPE_SUBTITLE;
+    else if (GST_IS_DISCOVERER_CONTAINER_INFO (info))
+      ps->st = STREAM_TYPE_CONTAINER;
+    gst_tag_list_foreach (tags, send_tag_foreach, ps);
+    ps->st = STREAM_TYPE_NONE;
+  }
+
+  if (ps->time_to_leave)
+    return;
+
+  if (GST_IS_DISCOVERER_AUDIO_INFO (info))
+    send_audio_info (GST_DISCOVERER_AUDIO_INFO (info), ps);
+  else if (GST_IS_DISCOVERER_VIDEO_INFO (info))
+    send_video_info (GST_DISCOVERER_VIDEO_INFO (info), ps);
+  else if (GST_IS_DISCOVERER_SUBTITLE_INFO (info))
+    send_subtitle_info (GST_DISCOVERER_SUBTITLE_INFO (info), ps);
+  else if (GST_IS_DISCOVERER_CONTAINER_INFO (info))
+  {
+    GstDiscovererContainerInfo *c = GST_DISCOVERER_CONTAINER_INFO (info);
+    GList *children = gst_discoverer_container_info_get_streams (c);
+    if (children)
+    {
+      GstDiscovererStreamInfo *sinfo = children->data;
+      /* send_streams () will unref it */
+      gst_discoverer_stream_info_ref (sinfo);
+      send_streams (sinfo, ps);
+      gst_discoverer_stream_info_list_free (children);
+    }
+  }
+}
+
+
+static void
+send_tag_foreach (const GstTagList * tags, const gchar * tag,
+    gpointer user_data)
+{
+  PrivStruct *ps = (PrivStruct *) user_data;
+  size_t i;
+  size_t tagl = sizeof (__known_tags) / sizeof (struct KnownTag);
+  struct KnownTag *kt = NULL;
+
+  GValue val = { 0, };
+  gchar *str;
+
+  GstSample *sample;
+
+  if (ps->time_to_leave)
+    return;
+
+  for (i = 0; i < tagl; i++)
+  {
+    if (strcmp (__known_tags[i].gst_tag_id, tag) != 0)
+      continue;
+    kt = &__known_tags[i];
+    break;
+  }
+  if (kt == NULL)
+    return;
+
+  gst_tag_list_copy_value (&val, tags, tag);
+
+  switch (G_VALUE_TYPE (&val))
+  {
+  case G_TYPE_STRING:
+    str = g_value_dup_string (&val);
+    break;
+  case G_TYPE_UINT:
+  case G_TYPE_DOUBLE:
+    str = gst_value_serialize (&val);
+    break;
+  default:
+    if (G_VALUE_TYPE (&val) == GST_TYPE_SAMPLE && (sample = gst_value_get_sample (&val)))
+    {
+      GstMapInfo mi;
+      const gchar *structname;
+      GstCaps *caps;
+
+      caps = gst_sample_get_caps (sample);
+      if (caps)
+      {
+        GstTagImageType imagetype;
+        const GstStructure *info;
+        GstBuffer *buf;
+        const gchar *mime_type;
+        enum EXTRACTOR_MetaType le_type;
+
+        mime_type = gst_structure_get_name (gst_caps_get_structure (caps, 0));
+        info = gst_sample_get_info (sample);
+
+        if (!gst_structure_get (info, "image-type", GST_TYPE_TAG_IMAGE_TYPE, &imagetype, NULL))
+          le_type = EXTRACTOR_METATYPE_PICTURE;
+        else
+        {
+          switch (imagetype)
+          {
+          case GST_TAG_IMAGE_TYPE_NONE:
+          case GST_TAG_IMAGE_TYPE_UNDEFINED:

+          case GST_TAG_IMAGE_TYPE_FISH:

+          case GST_TAG_IMAGE_TYPE_ILLUSTRATION:

+          default:
+            le_type = EXTRACTOR_METATYPE_PICTURE;
+            break;
+          case GST_TAG_IMAGE_TYPE_FRONT_COVER:

+          case GST_TAG_IMAGE_TYPE_BACK_COVER:

+          case GST_TAG_IMAGE_TYPE_LEAFLET_PAGE:

+          case GST_TAG_IMAGE_TYPE_MEDIUM:

+            le_type = EXTRACTOR_METATYPE_COVER_PICTURE;
+            break;
+          case GST_TAG_IMAGE_TYPE_LEAD_ARTIST:
+          case GST_TAG_IMAGE_TYPE_ARTIST:
+          case GST_TAG_IMAGE_TYPE_CONDUCTOR:
+          case GST_TAG_IMAGE_TYPE_BAND_ORCHESTRA:
+          case GST_TAG_IMAGE_TYPE_COMPOSER:
+          case GST_TAG_IMAGE_TYPE_LYRICIST:
+            le_type = EXTRACTOR_METATYPE_CONTRIBUTOR_PICTURE;
+            break;
+          case GST_TAG_IMAGE_TYPE_RECORDING_LOCATION:
+          case GST_TAG_IMAGE_TYPE_DURING_RECORDING:
+          case GST_TAG_IMAGE_TYPE_DURING_PERFORMANCE:
+          case GST_TAG_IMAGE_TYPE_VIDEO_CAPTURE:
+            le_type = EXTRACTOR_METATYPE_EVENT_PICTURE;
+            break;
+          case GST_TAG_IMAGE_TYPE_BAND_ARTIST_LOGO:

+          case GST_TAG_IMAGE_TYPE_PUBLISHER_STUDIO_LOGO:

+            le_type = EXTRACTOR_METATYPE_LOGO;
+            break;
+          }
+        }
+
+        buf = gst_sample_get_buffer (sample);
+        gst_buffer_map (buf, &mi, GST_MAP_READ);
+        ps->time_to_leave = ps->ec->proc (ps->ec->cls, "gstreamer", le_type,
+            EXTRACTOR_METAFORMAT_BINARY, mime_type,
+            (const char *) mi.data, mi.size);
+        gst_buffer_unmap (buf, &mi);
+      }
+    }
+    else
+      str = gst_value_serialize (&val);
+    break;
+  }
+  if (str != NULL)
+  {
+    /* We have one tag-processing routine and use it for different
+     * stream types. However, tags themselves don't know the type of the
+     * stream they are attached to. We remember that before listing the
+     * tags, and adjust LE type accordingly.
+     */
+    enum EXTRACTOR_MetaType le_type = kt->le_type;
+    switch (kt->le_type)
+    {
+    case EXTRACTOR_METATYPE_LANGUAGE:
+      switch (ps->st)
+      {
+      case STREAM_TYPE_AUDIO:
+        le_type = EXTRACTOR_METATYPE_AUDIO_LANGUAGE;
+        break;
+      case STREAM_TYPE_SUBTITLE:
+        le_type = EXTRACTOR_METATYPE_SUBTITLE_LANGUAGE;
+        break;
+      case STREAM_TYPE_VIDEO:
+        le_type = EXTRACTOR_METATYPE_VIDEO_LANGUAGE; /* New! */
+        break;
+      default:
+        break;
+      }
+      break;
+    case EXTRACTOR_METATYPE_BITRATE:
+      switch (ps->st)
+      {
+      case STREAM_TYPE_AUDIO:
+        le_type = EXTRACTOR_METATYPE_AUDIO_BITRATE;
+        break;
+      case STREAM_TYPE_VIDEO:
+        le_type = EXTRACTOR_METATYPE_VIDEO_BITRATE;
+        break;
+      default:
+        break;
+      }
+      break;
+    case EXTRACTOR_METATYPE_MAXIMUM_BITRATE:
+      switch (ps->st)
+      {
+      case STREAM_TYPE_AUDIO:
+        le_type = EXTRACTOR_METATYPE_MAXIMUM_AUDIO_BITRATE;
+        break;
+      case STREAM_TYPE_VIDEO:
+        le_type = EXTRACTOR_METATYPE_MAXIMUM_VIDEO_BITRATE;
+        break;
+      default:
+        break;
+      }
+      break;
+    case EXTRACTOR_METATYPE_IMAGE_DIMENSIONS:
+      switch (ps->st)
+      {
+      case STREAM_TYPE_VIDEO:
+        le_type = EXTRACTOR_METATYPE_VIDEO_DIMENSIONS;
+        break;
+      default:
+        break;
+      }
+      break;
+    default:
+      break;
+    }
+    ps->time_to_leave = ps->ec->proc (ps->ec->cls, "gstreamer", le_type,
+        EXTRACTOR_METAFORMAT_UTF8, "text/plain",
+        (const char *) str, strlen (str) + 1);
+  }
+
+  g_free (str);
+  g_value_unset (&val);
+}
+
+static void
+send_toc_tags_foreach (const GstTagList * tags, const gchar * tag,
+    gpointer user_data)
+{
+  PrivStruct *ps = (PrivStruct *) user_data;
+  GValue val = { 0, };
+  gchar *topen, *str, *tclose;
+
+  gst_tag_list_copy_value (&val, tags, tag);
+
+  switch (G_VALUE_TYPE (&val))
+  {
+  case G_TYPE_STRING:
+    str = g_value_dup_string (&val);
+    break;
+  case G_TYPE_UINT:
+  case G_TYPE_INT:
+  case G_TYPE_DOUBLE:
+    str = gst_value_serialize (&val);
+    break;
+  default:
+    /* This is a potential source of invalid characters */
+    /* And it also might attempt to serialize binary data - such as images. */
+    str = NULL;
+    break;
+  }
+  if (str != NULL)
+  {
+    topen = g_strdup_printf ("%*.*s<%s>", ps->toc_depth * 2,
+      ps->toc_depth * 2, " ", tag);
+    tclose = g_strdup_printf ("%*.*s</%s>\n", ps->toc_depth * 2,
+      ps->toc_depth * 2, " ", tag);
+
+    if (ps->toc_print_phase)
+      ps->toc_pos += g_snprintf (&ps->toc[ps->toc_pos],
+          ps->toc_length - ps->toc_pos, "%s%s%s", topen, str, tclose);
+    else
+      ps->toc_length += strlen (topen) + strlen (str) + strlen (tclose);
+    g_free (topen);
+    g_free (tclose);
+    g_free (str);
+  }
+  g_value_unset (&val);
+}
+
+static void
+send_toc_foreach (gpointer data, gpointer user_data)
+{
+  PrivStruct *ps = (PrivStruct *) user_data;
+  GstTocEntry *entry = (GstTocEntry *) data;
+  GstTagList *tags;
+  GList *subentries;
+  gint64 start, stop;
+  GstTocEntryType entype;
+
+  entype = gst_toc_entry_get_entry_type (entry);
+  if (GST_TOC_ENTRY_TYPE_INVALID != entype)
+  {
+    char *s;
+    gst_toc_entry_get_start_stop_times (entry, &start, &stop);
+    s = g_strdup_printf ("%*.*s<%s start=\"%" GST_TIME_FORMAT "\" stop=\"%"
+      GST_TIME_FORMAT"\">\n", ps->toc_depth * 2, ps->toc_depth * 2, " ",
+      gst_toc_entry_type_get_nick (entype), GST_TIME_ARGS (start),
+      GST_TIME_ARGS (stop));
+    if (ps->toc_print_phase)
+      ps->toc_pos += g_snprintf (&ps->toc[ps->toc_pos], ps->toc_length - ps->toc_pos, "%s", s);
+    else
+      ps->toc_length += strlen (s);
+    g_free (s);
+    ps->toc_depth += 1;
+    tags = gst_toc_entry_get_tags (entry);
+    if (tags)
+    {
+      if (ps->toc_print_phase)
+        ps->toc_pos += g_snprintf (&ps->toc[ps->toc_pos], ps->toc_length - ps->toc_pos,
+        "%*.*s<tags>\n", ps->toc_depth * 2, ps->toc_depth * 2, " ");
+      else
+        ps->toc_length += strlen ("<tags>\n") + ps->toc_depth * 2;
+      ps->toc_depth += 1;
+      gst_tag_list_foreach (tags, send_toc_tags_foreach, ps);
+      ps->toc_depth -= 1;
+      if (ps->toc_print_phase)
+        ps->toc_pos += g_snprintf (&ps->toc[ps->toc_pos], ps->toc_length - ps->toc_pos,
+        "%*.*s</tags>\n", ps->toc_depth * 2, ps->toc_depth * 2, " ");
+      else
+        ps->toc_length += strlen ("</tags>\n") + ps->toc_depth * 2;
+    }
+
+    subentries = gst_toc_entry_get_sub_entries (entry);
+    g_list_foreach (subentries, send_toc_foreach, ps);
+    ps->toc_depth -= 1;
+
+    s = g_strdup_printf ("%*.*s</%s>\n", ps->toc_depth * 2, ps->toc_depth * 2, " ",
+      gst_toc_entry_type_get_nick (entype));
+    if (ps->toc_print_phase)
+      ps->toc_pos += g_snprintf (&ps->toc[ps->toc_pos], ps->toc_length - ps->toc_pos, "%s", s);
+    else
+      ps->toc_length += strlen (s);
+    g_free (s);
+  }
+}
+
+static void
+send_streams (GstDiscovererStreamInfo *info, PrivStruct *ps)
+{
+  while (NULL != info && !ps->time_to_leave)
+  {
+    GstDiscovererStreamInfo *next;
+    send_stream_info (info, ps);
+    next = gst_discoverer_stream_info_get_next (info);
+    gst_discoverer_stream_info_unref (info);
+    info = next;
+  }
+}
+
+#define TOC_XML_HEADER "<?xml version=\"1.0\" encoding=\"UTF-8\" ?>\n"
+
+static void
+send_info (GstDiscovererInfo * info, PrivStruct *ps)
+{
+  const GstTagList *tags;
+  const GstToc *toc;
+  gchar *s;
+  GstDiscovererStreamInfo *sinfo;
+  GstClockTime duration;
+
+  duration = gst_discoverer_info_get_duration (info);
+  if (duration > 0)
+  {
+    s = g_strdup_printf ("%" GST_TIME_FORMAT,
+        GST_TIME_ARGS (gst_discoverer_info_get_duration (info)));
+    if (s)
+      ps->time_to_leave = ps->ec->proc (ps->ec->cls, "gstreamer",
+          EXTRACTOR_METATYPE_DURATION, EXTRACTOR_METAFORMAT_UTF8, "text/plain",
+          (const char *) s, strlen (s) + 1);
+    g_free (s);
+  }
+
+  if (ps->time_to_leave)
+    return;
+
+  if ((tags = gst_discoverer_info_get_tags (info)))
+  {
+    gst_tag_list_foreach (tags, send_tag_foreach, ps);
+  }
+
+  if (ps->time_to_leave)
+    return;
+
+  if (toc = gst_discoverer_info_get_toc (info))
+  {
+    GList *entries;
+
+    entries = gst_toc_get_entries (toc);
+    ps->toc_print_phase = FALSE;
+    ps->toc_length = 0;
+    g_list_foreach (entries, send_toc_foreach, ps);
+
+    /* FIXME: correct limit */
+    if (ps->toc_length > 0 && ps->toc_length < 32*1024 - 1 - strlen (TOC_XML_HEADER))
+    {
+      ps->toc_print_phase = TRUE;
+      ps->toc_length += 1 + strlen (TOC_XML_HEADER);
+      ps->toc = g_malloc (ps->toc_length);
+      ps->toc_pos = 0;
+      ps->toc_pos += g_snprintf (&ps->toc[ps->toc_pos], ps->toc_length - ps->toc_pos, "%s", TOC_XML_HEADER);
+      g_list_foreach (entries, send_toc_foreach, ps);
+      ps->toc[ps->toc_length - 1] = '\0';
+      ps->time_to_leave = ps->ec->proc (ps->ec->cls, "gstreamer",
+          EXTRACTOR_METATYPE_TOC, EXTRACTOR_METAFORMAT_XML, "application/xml",
+          (const char *) ps->toc, ps->toc_length);
+
+    }
+  }
+
+  if (ps->time_to_leave)
+    return;
+
+  sinfo = gst_discoverer_info_get_stream_info (info);
+  send_streams (sinfo, ps);
+}
+
+static void
+send_discovered_info (GstDiscovererInfo * info, PrivStruct * ps)
+{
+  GstDiscovererResult result;
+
+  /* Docs don't say that info is guaranteed to be non-NULL */
+  if (NULL == info)
+    return;
+  result = gst_discoverer_info_get_result (info);
+
+  switch (result)
+  {
+  case GST_DISCOVERER_OK:
+    break;
+  case GST_DISCOVERER_URI_INVALID:
+    break;
+  case GST_DISCOVERER_ERROR:
+    break;
+  case GST_DISCOVERER_TIMEOUT:
+    break;
+  case GST_DISCOVERER_BUSY:
+    break;
+  case GST_DISCOVERER_MISSING_PLUGINS:
+    break;
+  }
+
+  send_info (info, ps);
+}
+
+/* end of gstreamer_extractor.c */