2 * Copyright (C) 2003 Benjamin Otte <in7y118@public.uni-hamburg.de>
4 * gsttag.c: tag support (aka metadata)
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Library General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Library General Public License for more details.
16 * You should have received a copy of the GNU Library General Public
17 * License along with this library; if not, write to the
18 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 * Boston, MA 02111-1307, USA.
26 #include "gst_private.h"
27 #include "gst-i18n-lib.h"
32 #include <gobject/gvaluecollector.h>
35 #define GST_TAG_IS_VALID(tag) (gst_tag_get_info (tag) != NULL)
38 GType type; /* type the data is in */
40 gchar * nick; /* translated name */
41 gchar * blurb; /* translated description of type */
43 GstTagMergeFunc merge_func; /* functions to merge the values */
44 GstTagFlag flag; /* type of tag */
47 #define TAGLIST "taglist"
48 static GQuark gst_tag_list_quark;
49 static GMutex *__tag_mutex;
50 static GHashTable *__tags;
51 #define TAG_LOCK g_mutex_lock (__tag_mutex)
52 #define TAG_UNLOCK g_mutex_unlock (__tag_mutex)
55 _gst_tag_initialize (void)
57 gst_tag_list_quark = g_quark_from_static_string (TAGLIST);
58 __tag_mutex = g_mutex_new ();
59 __tags = g_hash_table_new (g_direct_hash, g_direct_equal);
60 gst_tag_register (GST_TAG_TITLE, GST_TAG_FLAG_META,
63 _("commonly used title"),
64 gst_tag_merge_strings_with_comma);
65 gst_tag_register (GST_TAG_ARTIST, GST_TAG_FLAG_META,
68 _("person(s) responsible for the recording"),
69 gst_tag_merge_strings_with_comma);
70 gst_tag_register (GST_TAG_ALBUM, GST_TAG_FLAG_META,
73 _("album containing this data"),
74 gst_tag_merge_strings_with_comma);
75 gst_tag_register (GST_TAG_DATE, GST_TAG_FLAG_META,
76 G_TYPE_UINT, /* FIXME: own data type for dates? */
78 _("date the data was created (in Julian calendar days)"),
80 gst_tag_register (GST_TAG_GENRE, GST_TAG_FLAG_META,
83 _("genre this data belongs to"),
84 gst_tag_merge_strings_with_comma);
85 gst_tag_register (GST_TAG_COMMENT, GST_TAG_FLAG_META,
88 _("free text commenting the data"),
89 gst_tag_merge_strings_with_comma);
90 gst_tag_register (GST_TAG_TRACK_NUMBER, GST_TAG_FLAG_META,
93 _("track number inside a collection"),
94 gst_tag_merge_use_first);
95 gst_tag_register (GST_TAG_TRACK_COUNT, GST_TAG_FLAG_META,
98 _("count of tracks inside collection this track belongs to"),
99 gst_tag_merge_use_first);
100 gst_tag_register (GST_TAG_LOCATION, GST_TAG_FLAG_META,
103 _("original location of file as a URI"),
104 gst_tag_merge_strings_with_comma);
105 gst_tag_register (GST_TAG_DESCRIPTION, GST_TAG_FLAG_META,
108 _("short text describing the content of the data"),
109 gst_tag_merge_strings_with_comma);
110 gst_tag_register (GST_TAG_VERSION, GST_TAG_FLAG_META,
113 _("version of this data"),
115 gst_tag_register (GST_TAG_ISRC, GST_TAG_FLAG_META,
118 _("International Standard Recording Code - see http://www.ifpi.org/isrc/"),
120 gst_tag_register (GST_TAG_ORGANIZATION, GST_TAG_FLAG_META,
123 _("organization"), /* FIXME */
124 gst_tag_merge_strings_with_comma);
125 gst_tag_register (GST_TAG_COPYRIGHT, GST_TAG_FLAG_META,
128 _("copyright notice of the data"),
130 gst_tag_register (GST_TAG_CONTACT, GST_TAG_FLAG_META,
133 _("contact information"),
134 gst_tag_merge_strings_with_comma);
135 gst_tag_register (GST_TAG_LICENSE, GST_TAG_FLAG_META,
138 _("license of data"),
140 gst_tag_register (GST_TAG_PERFORMER, GST_TAG_FLAG_META,
143 _("person(s) performing"),
144 gst_tag_merge_strings_with_comma);
145 gst_tag_register (GST_TAG_DURATION,
146 G_TYPE_UINT64, GST_TAG_FLAG_DECODED,
148 _("length in GStreamer time units (nanoseconds)"),
150 gst_tag_register (GST_TAG_CODEC, GST_TAG_FLAG_ENCODED,
153 _("codec the data is stored in"),
154 gst_tag_merge_strings_with_comma);
155 gst_tag_register (GST_TAG_BITRATE, GST_TAG_FLAG_ENCODED,
158 _("exact or average bitrate in bits/s"),
160 gst_tag_register (GST_TAG_NOMINAL_BITRATE, GST_TAG_FLAG_ENCODED,
162 _("nominal bitrate"),
163 _("nominal bitrate in bits/s"),
165 gst_tag_register (GST_TAG_MINIMUM_BITRATE, GST_TAG_FLAG_ENCODED,
167 _("minimum bitrate"),
168 _("minimum bitrate in bits/s"),
170 gst_tag_register (GST_TAG_MAXIMUM_BITRATE, GST_TAG_FLAG_ENCODED,
172 _("maximum bitrate"),
173 _("maximum bitrate in bits/s"),
175 gst_tag_register (GST_TAG_ENCODER_VERSION, GST_TAG_FLAG_ENCODED,
177 _("encoder version"),
178 _("version of the encoder used to encode this stream"),
180 gst_tag_register (GST_TAG_SERIAL, GST_TAG_FLAG_ENCODED,
183 _("serial number of track"),
185 gst_tag_register (GST_TAG_TRACK_GAIN, GST_TAG_FLAG_META,
187 _("replaygain track gain"),
188 _("track gain in db"),
190 gst_tag_register (GST_TAG_TRACK_PEAK, GST_TAG_FLAG_META,
192 _("replaygain track peak"),
193 _("peak of the track"),
195 gst_tag_register (GST_TAG_ALBUM_GAIN, GST_TAG_FLAG_META,
197 _("replaygain album gain"),
198 _("album gain in db"),
200 gst_tag_register (GST_TAG_ALBUM_PEAK, GST_TAG_FLAG_META,
202 _("replaygain album peak"),
203 _("peak of the album"),
207 * gst_tag_merge_use_first:
208 * @dest: uninitialized GValue to store result in
209 * @src: GValue to copy from
211 * This is a convenience function for the func argument of gst_tag_register().
212 * It creates a copy of the first value from the list.
215 gst_tag_merge_use_first (GValue *dest, const GValue *src)
217 const GValue *ret = gst_value_list_get_value (src, 0);
219 g_value_init (dest, G_VALUE_TYPE (ret));
220 g_value_copy (ret, dest);
223 * gst_tag_merge_strings_with_comma:
224 * @dest: uninitialized GValue to store result in
225 * @src: GValue to copy from
227 * This is a convenience function for the func argument of gst_tag_register().
228 * It concatenates all given strings using a comma. The tag must be registered
229 * as a G_TYPE_STRING or this function will fail.
232 gst_tag_merge_strings_with_comma (GValue *dest, const GValue *src)
237 count = gst_value_list_get_size (src);
238 str = g_string_new (g_value_get_string (gst_value_list_get_value (src, 0)));
239 for (i = 1; i < count; i++) {
240 /* seperator between two string */
241 str = g_string_append (str, _(", "));
242 str = g_string_append (str, g_value_get_string (gst_value_list_get_value (src, 1)));
245 g_value_init (dest, G_TYPE_STRING);
246 g_value_set_string_take_ownership (dest, str->str);
247 g_string_free (str, FALSE);
250 gst_tag_lookup (GQuark entry)
255 ret = g_hash_table_lookup (__tags, GUINT_TO_POINTER (entry));
262 * @name: the name or identifier string
263 * @flag: a flag describing the type of tag info
264 * @type: the type this data is in
265 * @nick: human-readable name
266 * @blurb: a human-readable description about this tag
267 * @func: function for merging multiple values of this tag
269 * Registers a new tag type for the use with GStreamer's type system. If a type
270 * with that name is already registered, that one is used.
271 * The old registration may have used a different type however. So don't rely
272 * on your supplied values.
273 * If you know the type is already registered, use gst_tag_lookup instead.
274 * This function takes ownership of all supplied variables.
277 gst_tag_register (gchar *name, GstTagFlag flag, GType type,
278 gchar *nick, gchar *blurb, GstTagMergeFunc func)
283 g_return_if_fail (name != NULL);
284 g_return_if_fail (nick != NULL);
285 g_return_if_fail (blurb != NULL);
286 g_return_if_fail (type != 0 && type != GST_TYPE_LIST);
288 key = g_quark_from_string (name);
289 info = gst_tag_lookup (key);
290 g_return_if_fail (info == NULL);
292 info = g_new (GstTagInfo, 1);
297 info->merge_func = func;
300 g_hash_table_insert (__tags, GUINT_TO_POINTER (key), info);
305 * @tag: name of the tag
307 * Checks if the given type is already registered.
309 * Returns: TRUE if the type is already registered
312 gst_tag_exists (const gchar *tag)
314 g_return_val_if_fail (tag != NULL, FALSE);
316 return gst_tag_lookup (g_quark_from_string (tag)) != NULL;
322 * Gets the #GType used for this tag.
324 * Returns: the #GType of this tag
327 gst_tag_get_type (const gchar *tag)
331 g_return_val_if_fail (tag != NULL, 0);
332 info = gst_tag_lookup (g_quark_from_string (tag));
333 g_return_val_if_fail (info != NULL, 0);
341 * Returns the human-readable name of this tag, You must not change or free
344 * Returns: the human-readable name of this tag
347 gst_tag_get_nick (const gchar *tag)
351 g_return_val_if_fail (tag != NULL, NULL);
352 info = gst_tag_lookup (g_quark_from_string (tag));
353 g_return_val_if_fail (info != NULL, NULL);
358 * gst_tag_get_description:
361 * Returns the human-readable description of this tag, You must not change or
364 * Return the human-readable description of this tag
367 gst_tag_get_description (const gchar *tag)
371 g_return_val_if_fail (tag != NULL, NULL);
372 info = gst_tag_lookup (g_quark_from_string (tag));
373 g_return_val_if_fail (info != NULL, NULL);
378 * gst_tag_list_is_fixed:
381 * Checks if the given tag is fixed. A fixed tag can only contain one value.
382 * Unfixed tags can contain lists of values.
384 * Returns: TRUE, if the given tag is fixed.
387 gst_tag_is_fixed (const gchar *tag)
391 g_return_val_if_fail (tag != NULL, FALSE);
392 info = gst_tag_lookup (g_quark_from_string (tag));
393 g_return_val_if_fail (info != NULL, FALSE);
395 return info->merge_func == NULL;
400 * Creates a new empty GstTagList.
402 * Returns: An empty tag list
405 gst_tag_list_new (void)
407 return GST_TAG_LIST (gst_structure_new (TAGLIST, NULL));
411 * @p: Object that might be a taglist
413 * Checks if the given pointer is a taglist.
415 * Returns: TRUE, if the given pointer is a taglist
418 gst_is_tag_list (gconstpointer p)
420 g_return_val_if_fail (p != NULL, FALSE);
422 return ((GstStructure *) p)->name == gst_tag_list_quark;
426 GstTagMergeMode mode;
429 gst_tag_list_add_value_internal (GstStructure *list, GstTagMergeMode mode, GQuark tag, GValue *value)
431 GstTagInfo *info = gst_tag_lookup (tag);
432 const GValue *value2;
434 g_assert (info != NULL);
436 if (info->merge_func && (value2 = gst_structure_id_get_value (list, tag)) != NULL) {
437 GValue dest = { 0, };
439 case GST_TAG_MERGE_REPLACE_ALL:
440 case GST_TAG_MERGE_REPLACE:
441 gst_structure_id_set_value (list, tag, value);
443 case GST_TAG_MERGE_PREPEND:
444 gst_value_list_concat (&dest, value, value2);
445 gst_structure_id_set_value (list, tag, &dest);
446 g_value_unset (&dest);
448 case GST_TAG_MERGE_APPEND:
449 gst_value_list_concat (&dest, value2, value);
450 gst_structure_id_set_value (list, tag, &dest);
451 g_value_unset (&dest);
453 case GST_TAG_MERGE_KEEP:
454 case GST_TAG_MERGE_KEEP_ALL:
457 g_assert_not_reached ();
462 case GST_TAG_MERGE_APPEND:
463 case GST_TAG_MERGE_KEEP:
464 if (gst_structure_id_get_value (list, tag) != NULL)
467 case GST_TAG_MERGE_REPLACE_ALL:
468 case GST_TAG_MERGE_REPLACE:
469 case GST_TAG_MERGE_PREPEND:
470 gst_structure_id_set_value (list, tag, value);
472 case GST_TAG_MERGE_KEEP_ALL:
475 g_assert_not_reached ();
481 gst_tag_list_copy_foreach (GQuark tag, GValue *value, gpointer user_data)
483 GstTagCopyData *copy = (GstTagCopyData *) user_data;
485 gst_tag_list_add_value_internal (copy->list, copy->mode, tag, value);
490 * gst_tag_list_insert:
491 * @into: list to merge into
492 * @from: list to merge from
493 * @mode: the mode to use
495 * Inserts the tags of the second list into the first list using the given mode.
498 gst_tag_list_insert (GstTagList *into, const GstTagList *from, GstTagMergeMode mode)
502 g_return_if_fail (GST_IS_TAG_LIST (into));
503 g_return_if_fail (GST_IS_TAG_LIST (from));
504 g_return_if_fail (GST_TAG_MODE_IS_VALID (mode));
506 data.list = (GstStructure *) into;
508 if (mode == GST_TAG_MERGE_REPLACE_ALL) {
509 gst_structure_remove_all_fields (data.list);
511 gst_structure_foreach ((GstStructure *) from, gst_tag_list_copy_foreach, &data);
515 * @list: list to copy
517 * Copies a given #GstTagList.
519 * Returns: copy of the given list
522 gst_tag_list_copy (const GstTagList *list)
524 g_return_val_if_fail (GST_IS_TAG_LIST (list), NULL);
526 return GST_TAG_LIST (gst_structure_copy ((GstStructure *) list));
529 * gst_tag_list_merge:
530 * @list1: first list to merge
531 * @list2: second list to merge
532 * @mode: the mode to use
534 * Merges the two given lists into a new list. If one of the lists is NULL, a
535 * copy of the other is returned. If both lists are NULL, NULL is returned.
537 * Returns: the new list
540 gst_tag_list_merge (const GstTagList *list1, const GstTagList *list2, GstTagMergeMode mode)
542 g_return_val_if_fail (list1 == NULL || GST_IS_TAG_LIST (list1), NULL);
543 g_return_val_if_fail (list2 == NULL || GST_IS_TAG_LIST (list2), NULL);
544 g_return_val_if_fail (GST_TAG_MODE_IS_VALID (mode), NULL);
546 if (!list1 && !list2) {
549 return gst_tag_list_copy (list2);
551 return gst_tag_list_copy (list1);
555 ret = gst_tag_list_copy (list1);
556 gst_tag_list_insert (ret, list2, mode);
562 * @list: the list to free
564 * Frees the given list and all associated values.
567 gst_tag_list_free (GstTagList *list)
569 g_return_if_fail (GST_IS_TAG_LIST (list));
570 gst_structure_free ((GstStructure *) list);
573 * gst_tag_list_get_tag_size:
575 * @tag: the tag to query
577 * Checks how many value are stored in this tag list for the given tag.
579 * Returns: The number of tags stored
582 gst_tag_list_get_tag_size (const GstTagList *list, const gchar *tag)
586 g_return_val_if_fail (GST_IS_TAG_LIST (list), 0);
588 value = gst_structure_get_value ((GstStructure *) list, tag);
591 if (G_VALUE_TYPE (value) != GST_TYPE_LIST)
594 return gst_value_list_get_size (value);
598 * @list: list to set tags in
599 * @mode: the mode to use
601 * @...: NULL-terminated list of values to set
603 * Sets the values for the given tags using the specified mode.
606 gst_tag_list_add (GstTagList *list, GstTagMergeMode mode, const gchar *tag, ...)
610 g_return_if_fail (GST_IS_TAG_LIST (list));
611 g_return_if_fail (GST_TAG_MODE_IS_VALID (mode));
612 g_return_if_fail (tag != NULL);
614 va_start (args, tag);
615 gst_tag_list_add_valist (list, mode, tag, args);
619 * gst_tag_list_add_values:
620 * @list: list to set tags in
621 * @mode: the mode to use
623 * @...: GValues to set
625 * Sets the GValues for the given tags using the specified mode.
628 gst_tag_list_add_values (GstTagList *list, GstTagMergeMode mode, const gchar *tag, ...)
632 g_return_if_fail (GST_IS_TAG_LIST (list));
633 g_return_if_fail (GST_TAG_MODE_IS_VALID (mode));
634 g_return_if_fail (tag != NULL);
636 va_start (args, tag);
637 gst_tag_list_add_valist_values (list, mode, tag, args);
641 * gst_tag_list_add_valist:
642 * @list: list to set tags in
643 * @mode: the mode to use
645 * @var_args: tag / value pairs to set
647 * Sets the values for the given tags using the specified mode.
650 gst_tag_list_add_valist (GstTagList *list, GstTagMergeMode mode, const gchar *tag, va_list var_args)
656 g_return_if_fail (GST_IS_TAG_LIST (list));
657 g_return_if_fail (GST_TAG_MODE_IS_VALID (mode));
658 g_return_if_fail (tag != NULL);
660 while (tag != NULL) {
661 GValue value = { 0, };
662 quark = g_quark_from_string (tag);
663 info = gst_tag_lookup (quark);
665 g_warning ("no GstTag for %s", tag);
666 g_return_if_fail (info != NULL);
667 g_value_init (&value, info->type);
668 G_VALUE_COLLECT (&value, var_args, 0, &error);
670 g_warning ("%s: %s", G_STRLOC, error);
672 /* we purposely leak the value here, it might not be
673 * in a sane state if an error condition occoured
677 gst_tag_list_add_value_internal (list, mode, quark, &value);
678 g_value_unset (&value);
679 tag = va_arg (var_args, gchar *);
683 * gst_tag_list_add_valist_values:
684 * @list: list to set tags in
685 * @mode: the mode to use
687 * @var_args: tag / GValue pairs to set
689 * Sets the GValues for the given tags using the specified mode.
692 gst_tag_list_add_valist_values (GstTagList *list, GstTagMergeMode mode, const gchar *tag, va_list var_args)
697 g_return_if_fail (GST_IS_TAG_LIST (list));
698 g_return_if_fail (GST_TAG_MODE_IS_VALID (mode));
699 g_return_if_fail (tag != NULL);
701 while (tag != NULL) {
702 quark = g_quark_from_string (tag);
703 info = gst_tag_lookup (quark);
704 g_return_if_fail (info != NULL);
705 gst_tag_list_add_value_internal (list, mode, quark, va_arg (var_args, GValue *));
706 tag = va_arg (var_args, gchar *);
710 * gst_tag_list_remove_tag:
711 * @list: list to remove tag from
712 * @tag: tag to remove
714 * Removes the goven tag from the taglist.
717 gst_tag_list_remove_tag (GstTagList *list, const gchar *tag)
719 g_return_if_fail (GST_IS_TAG_LIST (list));
720 g_return_if_fail (tag != NULL);
722 gst_structure_remove_field ((GstStructure *) list, tag);
725 GstTagForeachFunc func;
726 GstTagList * tag_list;
730 structure_foreach_wrapper (GQuark field_id,
731 GValue *value, gpointer user_data)
733 TagForeachData *data = (TagForeachData *) user_data;
734 data->func (data->tag_list, g_quark_to_string (field_id), data->data);
738 * gst_tag_list_foreach:
739 * @list: list to iterate over
740 * @func: function to be called for each tag
741 * @user_data: user specified data
743 * Calls the given function for each tag inside the tag list. Note that if there
744 * is no tag, the function won't be called at all.
747 gst_tag_list_foreach (GstTagList *list, GstTagForeachFunc func, gpointer user_data)
751 g_return_if_fail (GST_IS_TAG_LIST (list));
752 g_return_if_fail (func != NULL);
755 data.tag_list = list;
756 data.data = user_data;
757 gst_structure_foreach ((GstStructure *) list, structure_foreach_wrapper, &data);
760 /***** tag events *****/
764 * @list: the tag list to put into the event or NULL for an empty list
766 * Creates a new tag event with the given list and takes ownership of it.
768 * Returns: a new tag event
771 gst_event_new_tag (GstTagList *list)
775 g_return_val_if_fail (list == NULL || GST_IS_TAG_LIST (list), NULL);
777 ret = gst_event_new (GST_EVENT_TAG);
779 list = gst_tag_list_new ();
780 ret->event_data.structure.structure = (GstStructure *) list;
785 * get_event_tag_get_list:
786 * @tag_event: a tagging #GstEvent
788 * Gets the taglist from a given tagging event.
790 * Returns: The #GstTagList of the event
793 gst_event_tag_get_list (GstEvent *tag_event)
795 g_return_val_if_fail (GST_IS_EVENT (tag_event), NULL);
796 g_return_val_if_fail (GST_EVENT_TYPE (tag_event) == GST_EVENT_TAG, NULL);
798 return GST_TAG_LIST (tag_event->event_data.structure.structure);
802 * gst_tag_list_get_value_index:
803 * @list: a #GStTagList
804 * @tag: tag to read out
805 * @index: number of entry to read out
807 * Gets the value that is at the given index for the given tag in the given
810 * Returns: The GValue for the specified entry or NULL if the tag wasn't available
811 * or the tag doesn't have as many entries
813 G_CONST_RETURN GValue *
814 gst_tag_list_get_value_index (const GstTagList *list, const gchar *tag, guint index)
818 g_return_val_if_fail (GST_IS_TAG_LIST (list), NULL);
819 g_return_val_if_fail (tag != NULL, NULL);
821 value = gst_structure_get_value ((GstStructure *) list, tag);
822 if (value == NULL) return NULL;
824 if (GST_VALUE_HOLDS_LIST (value)) {
825 if (index >= gst_value_list_get_size (value)) return NULL;
826 return gst_value_list_get_value (value, index);
828 if (index > 0) return NULL;
834 * gst_tag_list_copy_value:
835 * @dest: uninitialized #GValue to copy into
836 * @list: list to get the tag from
837 * @tag: tag to read out
839 * Copies the contents for the given tag into the value, merging multiple values
840 * into one if multiple values are associated with the tag.
841 * You must g_value_unset() the value after use.
843 * Returns: TRUE, if a value was copied, FALSE if the tag didn't exist in the
847 gst_tag_list_copy_value (GValue *dest, const GstTagList *list, const gchar *tag)
851 g_return_val_if_fail (GST_IS_TAG_LIST (list), FALSE);
852 g_return_val_if_fail (tag != NULL, FALSE);
853 g_return_val_if_fail (dest != NULL, FALSE);
854 g_return_val_if_fail (G_VALUE_TYPE (dest) == 0, FALSE);
856 src = gst_structure_get_value ((GstStructure *) list, tag);
857 if (!src) return FALSE;
859 if (G_VALUE_TYPE (src) == GST_TYPE_LIST) {
860 GstTagInfo *info = gst_tag_lookup (g_quark_from_string (tag));
861 /* must be there or lists aren't allowed */
862 g_assert (info->merge_func);
863 info->merge_func (dest, src);
865 g_value_init (dest, G_VALUE_TYPE (src));
866 g_value_copy (src, dest);
871 /***** evil macros to get all the gst_tag_list_get_*() functions right *****/
873 #define TAG_MERGE_FUNCS(name,type) \
875 gst_tag_list_get_ ## name (const GstTagList *list, const gchar *tag, \
880 g_return_val_if_fail (GST_IS_TAG_LIST (list), FALSE); \
881 g_return_val_if_fail (tag != NULL, FALSE); \
882 g_return_val_if_fail (value != NULL, FALSE); \
884 if (!gst_tag_list_copy_value (&v, list, tag)) \
886 *value = COPY_FUNC (g_value_get_ ## name (&v)); \
887 g_value_unset (&v); \
892 gst_tag_list_get_ ## name ## _index (const GstTagList *list, const gchar *tag, \
893 guint index, type *value) \
897 g_return_val_if_fail (GST_IS_TAG_LIST (list), FALSE); \
898 g_return_val_if_fail (tag != NULL, FALSE); \
899 g_return_val_if_fail (value != NULL, FALSE); \
901 if ((v = gst_tag_list_get_value_index (list, tag, index)) == NULL) \
903 *value = COPY_FUNC (g_value_get_ ## name (v)); \
907 #define COPY_FUNC /**/
908 TAG_MERGE_FUNCS (char, gchar)
909 TAG_MERGE_FUNCS (uchar, guchar)
910 TAG_MERGE_FUNCS (boolean, gboolean)
911 TAG_MERGE_FUNCS (int, gint)
912 TAG_MERGE_FUNCS (uint, guint)
913 TAG_MERGE_FUNCS (long, glong)
914 TAG_MERGE_FUNCS (ulong, gulong)
915 TAG_MERGE_FUNCS (int64, gint64)
916 TAG_MERGE_FUNCS (uint64, guint64)
917 TAG_MERGE_FUNCS (float, gfloat)
918 TAG_MERGE_FUNCS (double, gdouble)
921 #define COPY_FUNC g_strdup
922 TAG_MERGE_FUNCS (string, gchar *)