2 * Copyright (C) 2003 Benjamin Otte <in7y118@public.uni-hamburg.de>
4 * gsttaglist.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., 51 Franklin St, Fifth Floor,
19 * Boston, MA 02110-1301, USA.
25 * @short_description: List of tags and values used to describe media metadata
27 * List of tags and values used to describe media metadata.
29 * Strings in structures must be ASCII or UTF-8 encoded. Other encodings are
30 * not allowed. Strings must not be empty or %NULL.
37 #define GST_DISABLE_MINIOBJECT_INLINE_FUNCTIONS
38 #include "gst_private.h"
39 #include "math-compat.h"
40 #include <glib/gi18n-lib.h>
41 #include "gsttaglist.h"
44 #include "gstbuffer.h"
46 #include "gststructure.h"
48 #include <gobject/gvaluecollector.h>
51 /* FIXME: add category for tags */
52 #define GST_CAT_TAGS GST_CAT_DEFAULT
54 #define GST_TAG_IS_VALID(tag) (gst_tag_get_info (tag) != NULL)
56 typedef struct _GstTagListImpl
60 GstStructure *structure;
64 #define GST_TAG_LIST_STRUCTURE(taglist) ((GstTagListImpl*)(taglist))->structure
65 #define GST_TAG_LIST_SCOPE(taglist) ((GstTagListImpl*)(taglist))->scope
69 GType type; /* type the data is in */
71 const gchar *nick; /* translated short description */
72 const gchar *blurb; /* translated long description */
74 GstTagMergeFunc merge_func; /* functions to merge the values */
75 GstTagFlag flag; /* type of tag */
76 GQuark name_quark; /* quark for the name */
80 #define g_value_get_char g_value_get_schar
82 static GMutex __tag_mutex;
83 #define TAG_LOCK g_mutex_lock (&__tag_mutex)
84 #define TAG_UNLOCK g_mutex_unlock (&__tag_mutex)
86 /* tags hash table: maps tag name string => GstTagInfo */
87 static GHashTable *__tags;
89 GType _gst_tag_list_type = 0;
90 GST_DEFINE_MINI_OBJECT_TYPE (GstTagList, gst_tag_list);
92 static void __gst_tag_list_free (GstTagList * list);
93 static GstTagList *__gst_tag_list_copy (const GstTagList * list);
96 * g_value_register_transform_func (_gst_tag_list_type, G_TYPE_STRING,
97 * _gst_structure_transform_to_string);
100 _priv_gst_tag_initialize (void)
102 g_mutex_init (&__tag_mutex);
104 _gst_tag_list_type = gst_tag_list_get_type ();
106 __tags = g_hash_table_new (g_str_hash, g_str_equal);
107 gst_tag_register_static (GST_TAG_TITLE, GST_TAG_FLAG_META,
109 _("title"), _("commonly used title"), gst_tag_merge_strings_with_comma);
110 gst_tag_register_static (GST_TAG_TITLE_SORTNAME, GST_TAG_FLAG_META,
112 _("title sortname"), _("commonly used title for sorting purposes"), NULL);
113 gst_tag_register_static (GST_TAG_ARTIST, GST_TAG_FLAG_META,
116 _("person(s) responsible for the recording"),
117 gst_tag_merge_strings_with_comma);
118 gst_tag_register_static (GST_TAG_ARTIST_SORTNAME, GST_TAG_FLAG_META,
120 _("artist sortname"),
121 _("person(s) responsible for the recording for sorting purposes"), NULL);
122 gst_tag_register_static (GST_TAG_ALBUM, GST_TAG_FLAG_META,
125 _("album containing this data"), gst_tag_merge_strings_with_comma);
126 gst_tag_register_static (GST_TAG_ALBUM_SORTNAME, GST_TAG_FLAG_META,
129 _("album containing this data for sorting purposes"), NULL);
130 gst_tag_register_static (GST_TAG_ALBUM_ARTIST, GST_TAG_FLAG_META,
133 _("The artist of the entire album, as it should be displayed"),
134 gst_tag_merge_strings_with_comma);
135 gst_tag_register_static (GST_TAG_ALBUM_ARTIST_SORTNAME, GST_TAG_FLAG_META,
137 _("album artist sortname"),
138 _("The artist of the entire album, as it should be sorted"), NULL);
139 gst_tag_register_static (GST_TAG_DATE, GST_TAG_FLAG_META, G_TYPE_DATE,
140 _("date"), _("date the data was created (as a GDate structure)"), NULL);
141 gst_tag_register_static (GST_TAG_DATE_TIME, GST_TAG_FLAG_META,
142 GST_TYPE_DATE_TIME, _("datetime"),
143 _("date and time the data was created (as a GstDateTime structure)"),
145 gst_tag_register_static (GST_TAG_GENRE, GST_TAG_FLAG_META,
148 _("genre this data belongs to"), gst_tag_merge_strings_with_comma);
149 gst_tag_register_static (GST_TAG_COMMENT, GST_TAG_FLAG_META,
152 _("free text commenting the data"), gst_tag_merge_use_first);
153 gst_tag_register_static (GST_TAG_EXTENDED_COMMENT, GST_TAG_FLAG_META,
155 _("extended comment"),
156 _("free text commenting the data in key=value or key[en]=comment form"),
157 gst_tag_merge_use_first);
158 gst_tag_register_static (GST_TAG_TRACK_NUMBER, GST_TAG_FLAG_META,
161 _("track number inside a collection"), gst_tag_merge_use_first);
162 gst_tag_register_static (GST_TAG_TRACK_COUNT, GST_TAG_FLAG_META,
165 _("count of tracks inside collection this track belongs to"),
166 gst_tag_merge_use_first);
167 gst_tag_register_static (GST_TAG_ALBUM_VOLUME_NUMBER, GST_TAG_FLAG_META,
170 _("disc number inside a collection"), gst_tag_merge_use_first);
171 gst_tag_register_static (GST_TAG_ALBUM_VOLUME_COUNT, GST_TAG_FLAG_META,
174 _("count of discs inside collection this disc belongs to"),
175 gst_tag_merge_use_first);
176 gst_tag_register_static (GST_TAG_LOCATION, GST_TAG_FLAG_META,
178 _("location"), _("Origin of media as a URI (location, where the "
179 "original of the file or stream is hosted)"),
180 gst_tag_merge_strings_with_comma);
181 gst_tag_register_static (GST_TAG_HOMEPAGE, GST_TAG_FLAG_META,
184 _("Homepage for this media (i.e. artist or movie homepage)"),
185 gst_tag_merge_strings_with_comma);
186 gst_tag_register_static (GST_TAG_DESCRIPTION, GST_TAG_FLAG_META,
187 G_TYPE_STRING, _("description"),
188 _("short text describing the content of the data"),
189 gst_tag_merge_strings_with_comma);
190 gst_tag_register_static (GST_TAG_VERSION, GST_TAG_FLAG_META, G_TYPE_STRING,
191 _("version"), _("version of this data"), NULL);
192 gst_tag_register_static (GST_TAG_ISRC, GST_TAG_FLAG_META, G_TYPE_STRING,
195 ("International Standard Recording Code - see http://www.ifpi.org/isrc/"),
197 /* FIXME: organization (fix what? tpm) */
198 gst_tag_register_static (GST_TAG_ORGANIZATION, GST_TAG_FLAG_META,
199 G_TYPE_STRING, _("organization"), _("organization"),
200 gst_tag_merge_strings_with_comma);
201 gst_tag_register_static (GST_TAG_COPYRIGHT, GST_TAG_FLAG_META,
202 G_TYPE_STRING, _("copyright"), _("copyright notice of the data"), NULL);
203 gst_tag_register_static (GST_TAG_COPYRIGHT_URI, GST_TAG_FLAG_META,
204 G_TYPE_STRING, _("copyright uri"),
205 _("URI to the copyright notice of the data"), NULL);
206 gst_tag_register_static (GST_TAG_ENCODED_BY, GST_TAG_FLAG_META, G_TYPE_STRING,
207 _("encoded by"), _("name of the encoding person or organization"),
208 gst_tag_merge_strings_with_comma);
209 gst_tag_register_static (GST_TAG_CONTACT, GST_TAG_FLAG_META,
211 _("contact"), _("contact information"), gst_tag_merge_strings_with_comma);
212 gst_tag_register_static (GST_TAG_LICENSE, GST_TAG_FLAG_META,
213 G_TYPE_STRING, _("license"), _("license of data"), NULL);
214 gst_tag_register_static (GST_TAG_LICENSE_URI, GST_TAG_FLAG_META,
215 G_TYPE_STRING, _("license uri"),
216 _("URI to the license of the data"), NULL);
217 gst_tag_register_static (GST_TAG_PERFORMER, GST_TAG_FLAG_META,
220 _("person(s) performing"), gst_tag_merge_strings_with_comma);
221 gst_tag_register_static (GST_TAG_COMPOSER, GST_TAG_FLAG_META,
224 _("person(s) who composed the recording"),
225 gst_tag_merge_strings_with_comma);
226 gst_tag_register_static (GST_TAG_CONDUCTOR, GST_TAG_FLAG_META,
229 _("conductor/performer refinement"), gst_tag_merge_strings_with_comma);
230 gst_tag_register_static (GST_TAG_DURATION, GST_TAG_FLAG_DECODED,
232 _("duration"), _("length in GStreamer time units (nanoseconds)"), NULL);
233 gst_tag_register_static (GST_TAG_CODEC, GST_TAG_FLAG_ENCODED,
236 _("codec the data is stored in"), gst_tag_merge_strings_with_comma);
237 gst_tag_register_static (GST_TAG_VIDEO_CODEC, GST_TAG_FLAG_ENCODED,
239 _("video codec"), _("codec the video data is stored in"), NULL);
240 gst_tag_register_static (GST_TAG_AUDIO_CODEC, GST_TAG_FLAG_ENCODED,
242 _("audio codec"), _("codec the audio data is stored in"), NULL);
243 gst_tag_register_static (GST_TAG_SUBTITLE_CODEC, GST_TAG_FLAG_ENCODED,
245 _("subtitle codec"), _("codec the subtitle data is stored in"), NULL);
246 gst_tag_register_static (GST_TAG_CONTAINER_FORMAT, GST_TAG_FLAG_ENCODED,
247 G_TYPE_STRING, _("container format"),
248 _("container format the data is stored in"), NULL);
249 gst_tag_register_static (GST_TAG_BITRATE, GST_TAG_FLAG_ENCODED,
250 G_TYPE_UINT, _("bitrate"), _("exact or average bitrate in bits/s"), NULL);
251 gst_tag_register_static (GST_TAG_NOMINAL_BITRATE, GST_TAG_FLAG_ENCODED,
252 G_TYPE_UINT, _("nominal bitrate"), _("nominal bitrate in bits/s"), NULL);
253 gst_tag_register_static (GST_TAG_MINIMUM_BITRATE, GST_TAG_FLAG_ENCODED,
254 G_TYPE_UINT, _("minimum bitrate"), _("minimum bitrate in bits/s"), NULL);
255 gst_tag_register_static (GST_TAG_MAXIMUM_BITRATE, GST_TAG_FLAG_ENCODED,
256 G_TYPE_UINT, _("maximum bitrate"), _("maximum bitrate in bits/s"), NULL);
257 gst_tag_register_static (GST_TAG_ENCODER, GST_TAG_FLAG_ENCODED,
259 _("encoder"), _("encoder used to encode this stream"), NULL);
260 gst_tag_register_static (GST_TAG_ENCODER_VERSION, GST_TAG_FLAG_ENCODED,
262 _("encoder version"),
263 _("version of the encoder used to encode this stream"), NULL);
264 gst_tag_register_static (GST_TAG_SERIAL, GST_TAG_FLAG_ENCODED,
265 G_TYPE_UINT, _("serial"), _("serial number of track"), NULL);
266 gst_tag_register_static (GST_TAG_TRACK_GAIN, GST_TAG_FLAG_META,
267 G_TYPE_DOUBLE, _("replaygain track gain"), _("track gain in db"), NULL);
268 gst_tag_register_static (GST_TAG_TRACK_PEAK, GST_TAG_FLAG_META,
269 G_TYPE_DOUBLE, _("replaygain track peak"), _("peak of the track"), NULL);
270 gst_tag_register_static (GST_TAG_ALBUM_GAIN, GST_TAG_FLAG_META,
271 G_TYPE_DOUBLE, _("replaygain album gain"), _("album gain in db"), NULL);
272 gst_tag_register_static (GST_TAG_ALBUM_PEAK, GST_TAG_FLAG_META,
273 G_TYPE_DOUBLE, _("replaygain album peak"), _("peak of the album"), NULL);
274 gst_tag_register_static (GST_TAG_REFERENCE_LEVEL, GST_TAG_FLAG_META,
275 G_TYPE_DOUBLE, _("replaygain reference level"),
276 _("reference level of track and album gain values"), NULL);
277 gst_tag_register_static (GST_TAG_LANGUAGE_CODE, GST_TAG_FLAG_META,
278 G_TYPE_STRING, _("language code"),
279 _("language code for this stream, conforming to ISO-639-1 or ISO-639-2"),
281 gst_tag_register_static (GST_TAG_LANGUAGE_NAME, GST_TAG_FLAG_META,
282 G_TYPE_STRING, _("language name"),
283 _("freeform name of the language this stream is in"), NULL);
284 gst_tag_register_static (GST_TAG_IMAGE, GST_TAG_FLAG_META, GST_TYPE_SAMPLE,
285 _("image"), _("image related to this stream"), gst_tag_merge_use_first);
286 gst_tag_register_static (GST_TAG_PREVIEW_IMAGE, GST_TAG_FLAG_META,
288 /* TRANSLATORS: 'preview image' = image that shows a preview of the full image */
289 _("preview image"), _("preview image related to this stream"), NULL);
290 gst_tag_register_static (GST_TAG_ATTACHMENT, GST_TAG_FLAG_META,
291 GST_TYPE_SAMPLE, _("attachment"), _("file attached to this stream"),
292 gst_tag_merge_use_first);
293 gst_tag_register_static (GST_TAG_BEATS_PER_MINUTE, GST_TAG_FLAG_META,
294 G_TYPE_DOUBLE, _("beats per minute"),
295 _("number of beats per minute in audio"), NULL);
296 gst_tag_register_static (GST_TAG_KEYWORDS, GST_TAG_FLAG_META, G_TYPE_STRING,
297 _("keywords"), _("comma separated keywords describing the content"),
298 gst_tag_merge_strings_with_comma);
299 gst_tag_register_static (GST_TAG_GEO_LOCATION_NAME, GST_TAG_FLAG_META,
300 G_TYPE_STRING, _("geo location name"),
301 _("human readable descriptive location of where "
302 "the media has been recorded or produced"), NULL);
303 gst_tag_register_static (GST_TAG_GEO_LOCATION_LATITUDE, GST_TAG_FLAG_META,
304 G_TYPE_DOUBLE, _("geo location latitude"),
305 _("geo latitude location of where the media has been recorded or "
306 "produced in degrees according to WGS84 (zero at the equator, "
307 "negative values for southern latitudes)"), NULL);
308 gst_tag_register_static (GST_TAG_GEO_LOCATION_LONGITUDE, GST_TAG_FLAG_META,
309 G_TYPE_DOUBLE, _("geo location longitude"),
310 _("geo longitude location of where the media has been recorded or "
311 "produced in degrees according to WGS84 (zero at the prime meridian "
312 "in Greenwich/UK, negative values for western longitudes)"), NULL);
313 gst_tag_register_static (GST_TAG_GEO_LOCATION_ELEVATION, GST_TAG_FLAG_META,
314 G_TYPE_DOUBLE, _("geo location elevation"),
315 _("geo elevation of where the media has been recorded or produced in "
316 "meters according to WGS84 (zero is average sea level)"), NULL);
317 gst_tag_register_static (GST_TAG_GEO_LOCATION_COUNTRY, GST_TAG_FLAG_META,
318 G_TYPE_STRING, _("geo location country"),
319 _("country (english name) where the media has been recorded "
320 "or produced"), NULL);
321 gst_tag_register_static (GST_TAG_GEO_LOCATION_CITY, GST_TAG_FLAG_META,
322 G_TYPE_STRING, _("geo location city"),
323 _("city (english name) where the media has been recorded "
324 "or produced"), NULL);
325 gst_tag_register_static (GST_TAG_GEO_LOCATION_SUBLOCATION, GST_TAG_FLAG_META,
326 G_TYPE_STRING, _("geo location sublocation"),
327 _("a location within a city where the media has been produced "
328 "or created (e.g. the neighborhood)"), NULL);
329 gst_tag_register_static (GST_TAG_GEO_LOCATION_HORIZONTAL_ERROR,
330 GST_TAG_FLAG_META, G_TYPE_DOUBLE, _("geo location horizontal error"),
331 _("expected error of the horizontal positioning measures (in meters)"),
333 gst_tag_register_static (GST_TAG_GEO_LOCATION_MOVEMENT_SPEED,
334 GST_TAG_FLAG_META, G_TYPE_DOUBLE, _("geo location movement speed"),
335 _("movement speed of the capturing device while performing the capture "
337 gst_tag_register_static (GST_TAG_GEO_LOCATION_MOVEMENT_DIRECTION,
338 GST_TAG_FLAG_META, G_TYPE_DOUBLE, _("geo location movement direction"),
339 _("indicates the movement direction of the device performing the capture"
340 " of a media. It is represented as degrees in floating point "
341 "representation, 0 means the geographic north, and increases "
343 gst_tag_register_static (GST_TAG_GEO_LOCATION_CAPTURE_DIRECTION,
344 GST_TAG_FLAG_META, G_TYPE_DOUBLE, _("geo location capture direction"),
345 _("indicates the direction the device is pointing to when capturing "
346 " a media. It is represented as degrees in floating point "
347 " representation, 0 means the geographic north, and increases "
349 gst_tag_register_static (GST_TAG_SHOW_NAME, GST_TAG_FLAG_META, G_TYPE_STRING,
350 /* TRANSLATORS: 'show name' = 'TV/radio/podcast show name' here */
352 _("Name of the tv/podcast/series show the media is from"),
353 gst_tag_merge_strings_with_comma);
354 gst_tag_register_static (GST_TAG_SHOW_SORTNAME, GST_TAG_FLAG_META,
356 /* TRANSLATORS: 'show sortname' = 'TV/radio/podcast show name as used for sorting purposes' here */
358 _("Name of the tv/podcast/series show the media is from, for sorting "
360 gst_tag_register_static (GST_TAG_SHOW_EPISODE_NUMBER, GST_TAG_FLAG_META,
361 G_TYPE_UINT, _("episode number"),
362 _("The episode number in the season the media is part of"),
363 gst_tag_merge_use_first);
364 gst_tag_register_static (GST_TAG_SHOW_SEASON_NUMBER, GST_TAG_FLAG_META,
365 G_TYPE_UINT, _("season number"),
366 _("The season number of the show the media is part of"),
367 gst_tag_merge_use_first);
368 gst_tag_register_static (GST_TAG_LYRICS, GST_TAG_FLAG_META, G_TYPE_STRING,
369 _("lyrics"), _("The lyrics of the media, commonly used for songs"),
370 gst_tag_merge_strings_with_comma);
371 gst_tag_register_static (GST_TAG_COMPOSER_SORTNAME, GST_TAG_FLAG_META,
372 G_TYPE_STRING, _("composer sortname"),
373 _("person(s) who composed the recording, for sorting purposes"), NULL);
374 gst_tag_register_static (GST_TAG_GROUPING, GST_TAG_FLAG_META, G_TYPE_STRING,
376 _("Groups related media that spans multiple tracks, like the different "
377 "pieces of a concerto. It is a higher level than a track, "
378 "but lower than an album"), NULL);
379 gst_tag_register_static (GST_TAG_USER_RATING, GST_TAG_FLAG_META, G_TYPE_UINT,
381 _("Rating attributed by a user. The higher the rank, "
382 "the more the user likes this media"), NULL);
383 gst_tag_register_static (GST_TAG_DEVICE_MANUFACTURER, GST_TAG_FLAG_META,
384 G_TYPE_STRING, _("device manufacturer"),
385 _("Manufacturer of the device used to create this media"), NULL);
386 gst_tag_register_static (GST_TAG_DEVICE_MODEL, GST_TAG_FLAG_META,
387 G_TYPE_STRING, _("device model"),
388 _("Model of the device used to create this media"), NULL);
389 gst_tag_register_static (GST_TAG_APPLICATION_NAME, GST_TAG_FLAG_META,
390 G_TYPE_STRING, _("application name"),
391 _("Application used to create the media"), NULL);
392 gst_tag_register_static (GST_TAG_APPLICATION_DATA, GST_TAG_FLAG_META,
393 GST_TYPE_SAMPLE, _("application data"),
394 _("Arbitrary application data to be serialized into the media"), NULL);
395 gst_tag_register_static (GST_TAG_IMAGE_ORIENTATION, GST_TAG_FLAG_META,
396 G_TYPE_STRING, _("image orientation"),
397 _("How the image should be rotated or flipped before display"), NULL);
398 gst_tag_register_static (GST_TAG_PUBLISHER, GST_TAG_FLAG_META,
401 _("Name of the label or publisher"), gst_tag_merge_strings_with_comma);
402 gst_tag_register_static (GST_TAG_INTERPRETED_BY, GST_TAG_FLAG_META,
405 _("Information about the people behind a remix and similar "
406 "interpretations"), gst_tag_merge_strings_with_comma);
407 gst_tag_register_static (GST_TAG_MIDI_BASE_NOTE, GST_TAG_FLAG_META,
409 _("midi-base-note"), _("Midi note number of the audio track."), NULL);
410 gst_tag_register_static (GST_TAG_PRIVATE_DATA, GST_TAG_FLAG_META,
412 _("private-data"), _("Private data"), gst_tag_merge_use_first);
417 * gst_tag_merge_use_first:
418 * @dest: (out caller-allocates): uninitialized GValue to store result in
419 * @src: GValue to copy from
421 * This is a convenience function for the func argument of gst_tag_register().
422 * It creates a copy of the first value from the list.
425 gst_tag_merge_use_first (GValue * dest, const GValue * src)
427 const GValue *ret = gst_value_list_get_value (src, 0);
429 g_value_init (dest, G_VALUE_TYPE (ret));
430 g_value_copy (ret, dest);
434 * gst_tag_merge_strings_with_comma:
435 * @dest: (out caller-allocates): uninitialized GValue to store result in
436 * @src: GValue to copy from
438 * This is a convenience function for the func argument of gst_tag_register().
439 * It concatenates all given strings using a comma. The tag must be registered
440 * as a G_TYPE_STRING or this function will fail.
443 gst_tag_merge_strings_with_comma (GValue * dest, const GValue * src)
448 count = gst_value_list_get_size (src);
449 str = g_string_new (g_value_get_string (gst_value_list_get_value (src, 0)));
450 for (i = 1; i < count; i++) {
451 /* separator between two strings */
452 g_string_append (str, _(", "));
453 g_string_append (str,
454 g_value_get_string (gst_value_list_get_value (src, i)));
457 g_value_init (dest, G_TYPE_STRING);
458 g_value_take_string (dest, g_string_free (str, FALSE));
462 gst_tag_lookup (const gchar * tag_name)
467 ret = g_hash_table_lookup (__tags, (gpointer) tag_name);
474 * gst_tag_register: (skip)
475 * @name: the name or identifier string
476 * @flag: a flag describing the type of tag info
477 * @type: the type this data is in
478 * @nick: human-readable name
479 * @blurb: a human-readable description about this tag
480 * @func: (allow-none): function for merging multiple values of this tag, or %NULL
482 * Registers a new tag type for the use with GStreamer's type system. If a type
483 * with that name is already registered, that one is used.
484 * The old registration may have used a different type however. So don't rely
485 * on your supplied values.
487 * Important: if you do not supply a merge function the implication will be
488 * that there can only be one single value for this tag in a tag list and
489 * any additional values will silently be discarded when being added (unless
490 * #GST_TAG_MERGE_REPLACE, #GST_TAG_MERGE_REPLACE_ALL, or
491 * #GST_TAG_MERGE_PREPEND is used as merge mode, in which case the new
492 * value will replace the old one in the list).
494 * The merge function will be called from gst_tag_list_copy_value() when
495 * it is required that one or more values for a tag be condensed into
496 * one single value. This may happen from gst_tag_list_get_string(),
497 * gst_tag_list_get_int(), gst_tag_list_get_double() etc. What will happen
498 * exactly in that case depends on how the tag was registered and if a
499 * merge function was supplied and if so which one.
501 * Two default merge functions are provided: gst_tag_merge_use_first() and
502 * gst_tag_merge_strings_with_comma().
505 gst_tag_register (const gchar * name, GstTagFlag flag, GType type,
506 const gchar * nick, const gchar * blurb, GstTagMergeFunc func)
508 g_return_if_fail (name != NULL);
509 g_return_if_fail (nick != NULL);
510 g_return_if_fail (blurb != NULL);
511 g_return_if_fail (type != G_TYPE_INVALID && type != GST_TYPE_LIST);
513 gst_tag_register_static (g_intern_string (name), flag, type,
514 g_intern_string (nick), g_intern_string (blurb), func);
518 * gst_tag_register_static: (skip)
519 * @name: the name or identifier string (string constant)
520 * @flag: a flag describing the type of tag info
521 * @type: the type this data is in
522 * @nick: human-readable name or short description (string constant)
523 * @blurb: a human-readable description for this tag (string constant)
524 * @func: (allow-none): function for merging multiple values of this tag, or %NULL
526 * Registers a new tag type for the use with GStreamer's type system.
528 * Same as gst_tag_register(), but @name, @nick, and @blurb must be
529 * static strings or inlined strings, as they will not be copied. (GStreamer
530 * plugins will be made resident once loaded, so this function can be used
531 * even from dynamically loaded plugins.)
534 gst_tag_register_static (const gchar * name, GstTagFlag flag, GType type,
535 const gchar * nick, const gchar * blurb, GstTagMergeFunc func)
539 g_return_if_fail (name != NULL);
540 g_return_if_fail (nick != NULL);
541 g_return_if_fail (blurb != NULL);
542 g_return_if_fail (type != G_TYPE_INVALID && type != GST_TYPE_LIST);
544 info = gst_tag_lookup (name);
547 g_return_if_fail (info->type == type);
551 info = g_slice_new (GstTagInfo);
554 info->name_quark = g_quark_from_static_string (name);
557 info->merge_func = func;
560 g_hash_table_insert (__tags, (gpointer) name, info);
566 * @tag: name of the tag
568 * Checks if the given type is already registered.
570 * Returns: %TRUE if the type is already registered
573 gst_tag_exists (const gchar * tag)
575 g_return_val_if_fail (tag != NULL, FALSE);
577 return gst_tag_lookup (tag) != NULL;
584 * Gets the #GType used for this tag.
586 * Returns: the #GType of this tag
589 gst_tag_get_type (const gchar * tag)
593 g_return_val_if_fail (tag != NULL, 0);
594 info = gst_tag_lookup (tag);
595 g_return_val_if_fail (info != NULL, 0);
604 * Returns the human-readable name of this tag, You must not change or free
607 * Returns: the human-readable name of this tag
610 gst_tag_get_nick (const gchar * tag)
614 g_return_val_if_fail (tag != NULL, NULL);
615 info = gst_tag_lookup (tag);
617 GST_WARNING ("Unknown tag: %s", tag);
626 * gst_tag_get_description:
629 * Returns the human-readable description of this tag, You must not change or
632 * Returns: the human-readable description of this tag
635 gst_tag_get_description (const gchar * tag)
639 g_return_val_if_fail (tag != NULL, NULL);
640 info = gst_tag_lookup (tag);
641 g_return_val_if_fail (info != NULL, NULL);
650 * Gets the flag of @tag.
652 * Returns: the flag of this tag.
655 gst_tag_get_flag (const gchar * tag)
659 g_return_val_if_fail (tag != NULL, GST_TAG_FLAG_UNDEFINED);
660 info = gst_tag_lookup (tag);
661 g_return_val_if_fail (info != NULL, GST_TAG_FLAG_UNDEFINED);
670 * Checks if the given tag is fixed. A fixed tag can only contain one value.
671 * Unfixed tags can contain lists of values.
673 * Returns: %TRUE, if the given tag is fixed.
676 gst_tag_is_fixed (const gchar * tag)
680 g_return_val_if_fail (tag != NULL, FALSE);
681 info = gst_tag_lookup (tag);
682 g_return_val_if_fail (info != NULL, FALSE);
684 return info->merge_func == NULL;
687 /* takes ownership of the structure */
689 gst_tag_list_new_internal (GstStructure * s, GstTagScope scope)
691 GstTagList *tag_list;
693 g_assert (s != NULL);
695 tag_list = (GstTagList *) g_slice_new (GstTagListImpl);
697 gst_mini_object_init (GST_MINI_OBJECT_CAST (tag_list), 0, GST_TYPE_TAG_LIST,
698 (GstMiniObjectCopyFunction) __gst_tag_list_copy, NULL,
699 (GstMiniObjectFreeFunction) __gst_tag_list_free);
701 GST_TAG_LIST_STRUCTURE (tag_list) = s;
702 GST_TAG_LIST_SCOPE (tag_list) = scope;
704 #ifdef DEBUG_REFCOUNT
705 GST_CAT_TRACE (GST_CAT_TAGS, "created taglist %p", tag_list);
712 __gst_tag_list_free (GstTagList * list)
714 g_return_if_fail (GST_IS_TAG_LIST (list));
716 #ifdef DEBUG_REFCOUNT
717 GST_CAT_TRACE (GST_CAT_TAGS, "freeing taglist %p", list);
720 gst_structure_free (GST_TAG_LIST_STRUCTURE (list));
723 memset (list, 0xff, sizeof (GstTagListImpl));
726 g_slice_free1 (sizeof (GstTagListImpl), list);
730 __gst_tag_list_copy (const GstTagList * list)
732 const GstStructure *s;
734 g_return_val_if_fail (GST_IS_TAG_LIST (list), NULL);
736 s = GST_TAG_LIST_STRUCTURE (list);
737 return gst_tag_list_new_internal (gst_structure_copy (s),
738 GST_TAG_LIST_SCOPE (list));
742 * gst_tag_list_new_empty:
744 * Creates a new empty GstTagList.
746 * Free-function: gst_tag_list_unref
748 * Returns: (transfer full): An empty tag list
751 gst_tag_list_new_empty (void)
754 GstTagList *tag_list;
756 s = gst_structure_new_id_empty (GST_QUARK (TAGLIST));
757 tag_list = gst_tag_list_new_internal (s, GST_TAG_SCOPE_STREAM);
764 * @...: %NULL-terminated list of values to set
766 * Creates a new taglist and appends the values for the given tags. It expects
767 * tag-value pairs like gst_tag_list_add(), and a %NULL terminator after the
768 * last pair. The type of the values is implicit and is documented in the API
769 * reference, but can also be queried at runtime with gst_tag_get_type(). It
770 * is an error to pass a value of a type not matching the tag type into this
771 * function. The tag list will make copies of any arguments passed
772 * (e.g. strings, buffers).
774 * After creation you might also want to set a #GstTagScope on the returned
775 * taglist to signal if the contained tags are global or stream tags. By
776 * default stream scope is assumes. See gst_tag_list_set_scope().
778 * Free-function: gst_tag_list_unref
780 * Returns: (transfer full): a new #GstTagList. Free with gst_tag_list_unref()
781 * when no longer needed.
784 gst_tag_list_new (const gchar * tag, ...)
789 g_return_val_if_fail (tag != NULL, NULL);
791 list = gst_tag_list_new_empty ();
792 va_start (args, tag);
793 gst_tag_list_add_valist (list, GST_TAG_MERGE_APPEND, tag, args);
800 * gst_tag_list_new_valist:
801 * @var_args: tag / value pairs to set
803 * Just like gst_tag_list_new(), only that it takes a va_list argument.
804 * Useful mostly for language bindings.
806 * Free-function: gst_tag_list_unref
808 * Returns: (transfer full): a new #GstTagList. Free with gst_tag_list_unref()
809 * when no longer needed.
812 gst_tag_list_new_valist (va_list var_args)
817 list = gst_tag_list_new_empty ();
819 tag = va_arg (var_args, gchar *);
820 gst_tag_list_add_valist (list, GST_TAG_MERGE_APPEND, tag, var_args);
826 * gst_tag_list_set_scope:
827 * @list: a #GstTagList
828 * @scope: new scope for @list
830 * Sets the scope of @list to @scope. By default the scope
831 * of a taglist is stream scope.
835 gst_tag_list_set_scope (GstTagList * list, GstTagScope scope)
837 g_return_if_fail (GST_IS_TAG_LIST (list));
838 g_return_if_fail (gst_tag_list_is_writable (list));
840 GST_TAG_LIST_SCOPE (list) = scope;
844 * gst_tag_list_get_scope:
845 * @list: a #GstTagList
847 * Gets the scope of @list.
849 * Returns: The scope of @list
852 gst_tag_list_get_scope (const GstTagList * list)
854 g_return_val_if_fail (GST_IS_TAG_LIST (list), GST_TAG_SCOPE_STREAM);
856 return GST_TAG_LIST_SCOPE (list);
860 * gst_tag_list_to_string:
861 * @list: a #GstTagList
863 * Serializes a tag list to a string.
865 * Returns: (transfer full): a newly-allocated string.
866 * The string must be freed with g_free() when no longer
870 gst_tag_list_to_string (const GstTagList * list)
872 g_return_val_if_fail (GST_IS_TAG_LIST (list), NULL);
874 return gst_structure_to_string (GST_TAG_LIST_STRUCTURE (list));
878 * gst_tag_list_new_from_string:
879 * @str: a string created with gst_tag_list_to_string()
881 * Deserializes a tag list.
883 * Returns: (transfer full) (nullable): a new #GstTagList, or %NULL in case of an
887 gst_tag_list_new_from_string (const gchar * str)
889 GstTagList *tag_list;
892 g_return_val_if_fail (str != NULL, NULL);
893 g_return_val_if_fail (g_str_has_prefix (str, "taglist"), NULL);
895 s = gst_structure_from_string (str, NULL);
899 tag_list = gst_tag_list_new_internal (s, GST_TAG_SCOPE_STREAM);
905 * gst_tag_list_n_tags:
906 * @list: A #GstTagList.
908 * Get the number of tags in @list.
910 * Returns: The number of tags in @list.
913 gst_tag_list_n_tags (const GstTagList * list)
915 g_return_val_if_fail (list != NULL, 0);
916 g_return_val_if_fail (GST_IS_TAG_LIST (list), 0);
918 return gst_structure_n_fields (GST_TAG_LIST_STRUCTURE (list));
922 * gst_tag_list_nth_tag_name:
923 * @list: A #GstTagList.
926 * Get the name of the tag in @list at @index.
928 * Returns: The name of the tag at @index.
931 gst_tag_list_nth_tag_name (const GstTagList * list, guint index)
933 g_return_val_if_fail (list != NULL, 0);
934 g_return_val_if_fail (GST_IS_TAG_LIST (list), 0);
936 return gst_structure_nth_field_name (GST_TAG_LIST_STRUCTURE (list), index);
940 * gst_tag_list_is_empty:
941 * @list: A #GstTagList.
943 * Checks if the given taglist is empty.
945 * Returns: %TRUE if the taglist is empty, otherwise %FALSE.
948 gst_tag_list_is_empty (const GstTagList * list)
950 g_return_val_if_fail (list != NULL, FALSE);
951 g_return_val_if_fail (GST_IS_TAG_LIST (list), FALSE);
953 return (gst_structure_n_fields (GST_TAG_LIST_STRUCTURE (list)) == 0);
957 gst_tag_list_fields_equal (GQuark field_id, const GValue * value2,
960 const GstStructure *struct1 = (const GstStructure *) data;
961 const GValue *value1 = gst_structure_id_get_value (struct1, field_id);
964 if (value1 == NULL) {
965 /* no value with this field id, clearly not equal */
969 if (gst_value_compare (value1, value2) == GST_VALUE_EQUAL)
972 /* fields not equal: add some tolerance for doubles, otherwise bail out */
973 if ((G_VALUE_TYPE (value1) == G_VALUE_TYPE (value2)) &&
974 G_VALUE_TYPE (value1) == G_TYPE_DOUBLE) {
975 d1 = g_value_get_double (value1);
976 d2 = g_value_get_double (value2);
978 /* This will only work for 'normal' values and values around 0,
979 * which should be good enough for our purposes here
980 * FIXME: maybe add this to gst_value_compare_double() ? */
981 return (fabs (d1 - d2) < 0.0000001);
989 * gst_tag_list_is_equal:
990 * @list1: a #GstTagList.
991 * @list2: a #GstTagList.
993 * Checks if the two given taglists are equal.
995 * Returns: %TRUE if the taglists are equal, otherwise %FALSE
998 gst_tag_list_is_equal (const GstTagList * list1, const GstTagList * list2)
1000 const GstStructure *s1, *s2;
1002 g_return_val_if_fail (GST_IS_TAG_LIST (list1), FALSE);
1003 g_return_val_if_fail (GST_IS_TAG_LIST (list2), FALSE);
1005 /* we don't just use gst_structure_is_equal() here so we can add some
1006 * tolerance for doubles, though maybe we should just add that to
1007 * gst_value_compare_double() as well? */
1008 s1 = GST_TAG_LIST_STRUCTURE (list1);
1009 s2 = GST_TAG_LIST_STRUCTURE (list2);
1011 if (G_UNLIKELY (s1 == s2))
1014 if (gst_structure_n_fields (s1) != gst_structure_n_fields (s2)) {
1018 return gst_structure_foreach (s1, gst_tag_list_fields_equal, (gpointer) s2);
1024 GstTagMergeMode mode;
1029 gst_tag_list_add_value_internal (GstTagList * tag_list, GstTagMergeMode mode,
1030 const gchar * tag, const GValue * value, GstTagInfo * info)
1032 GstStructure *list = GST_TAG_LIST_STRUCTURE (tag_list);
1033 const GValue *value2;
1037 info = gst_tag_lookup (tag);
1038 if (G_UNLIKELY (info == NULL)) {
1039 g_warning ("unknown tag '%s'", tag);
1044 if (G_UNLIKELY (!G_VALUE_HOLDS (value, info->type) &&
1045 !GST_VALUE_HOLDS_LIST (value))) {
1046 g_warning ("tag '%s' should hold value of type '%s', but value of "
1047 "type '%s' passed", info->nick, g_type_name (info->type),
1048 g_type_name (G_VALUE_TYPE (value)));
1052 tag_quark = info->name_quark;
1054 if (info->merge_func
1055 && (value2 = gst_structure_id_get_value (list, tag_quark)) != NULL) {
1056 GValue dest = { 0, };
1059 case GST_TAG_MERGE_REPLACE_ALL:
1060 case GST_TAG_MERGE_REPLACE:
1061 gst_structure_id_set_value (list, tag_quark, value);
1063 case GST_TAG_MERGE_PREPEND:
1064 if (GST_VALUE_HOLDS_LIST (value2) && !GST_VALUE_HOLDS_LIST (value))
1065 gst_value_list_prepend_value ((GValue *) value2, value);
1067 gst_value_list_merge (&dest, value, value2);
1068 gst_structure_id_take_value (list, tag_quark, &dest);
1071 case GST_TAG_MERGE_APPEND:
1072 if (GST_VALUE_HOLDS_LIST (value2) && !GST_VALUE_HOLDS_LIST (value))
1073 gst_value_list_append_value ((GValue *) value2, value);
1075 gst_value_list_merge (&dest, value2, value);
1076 gst_structure_id_take_value (list, tag_quark, &dest);
1079 case GST_TAG_MERGE_KEEP:
1080 case GST_TAG_MERGE_KEEP_ALL:
1083 g_assert_not_reached ();
1088 case GST_TAG_MERGE_APPEND:
1089 case GST_TAG_MERGE_KEEP:
1090 if (gst_structure_id_get_value (list, tag_quark) != NULL)
1093 case GST_TAG_MERGE_REPLACE_ALL:
1094 case GST_TAG_MERGE_REPLACE:
1095 case GST_TAG_MERGE_PREPEND:
1096 gst_structure_id_set_value (list, tag_quark, value);
1098 case GST_TAG_MERGE_KEEP_ALL:
1101 g_assert_not_reached ();
1108 gst_tag_list_copy_foreach (GQuark tag_quark, const GValue * value,
1111 GstTagCopyData *copy = (GstTagCopyData *) user_data;
1114 tag = g_quark_to_string (tag_quark);
1115 gst_tag_list_add_value_internal (copy->list, copy->mode, tag, value, NULL);
1121 * gst_tag_list_insert:
1122 * @into: list to merge into
1123 * @from: list to merge from
1124 * @mode: the mode to use
1126 * Inserts the tags of the @from list into the first list using the given mode.
1129 gst_tag_list_insert (GstTagList * into, const GstTagList * from,
1130 GstTagMergeMode mode)
1132 GstTagCopyData data;
1134 g_return_if_fail (GST_IS_TAG_LIST (into));
1135 g_return_if_fail (gst_tag_list_is_writable (into));
1136 g_return_if_fail (GST_IS_TAG_LIST (from));
1137 g_return_if_fail (GST_TAG_MODE_IS_VALID (mode));
1141 if (mode == GST_TAG_MERGE_REPLACE_ALL) {
1142 gst_structure_remove_all_fields (GST_TAG_LIST_STRUCTURE (into));
1144 gst_structure_foreach (GST_TAG_LIST_STRUCTURE (from),
1145 gst_tag_list_copy_foreach, &data);
1149 * gst_tag_list_merge:
1150 * @list1: (nullable): first list to merge
1151 * @list2: (nullable): second list to merge
1152 * @mode: the mode to use
1154 * Merges the two given lists into a new list. If one of the lists is %NULL, a
1155 * copy of the other is returned. If both lists are %NULL, %NULL is returned.
1157 * Free-function: gst_tag_list_unref
1159 * Returns: (transfer full) (nullable): the new list
1162 gst_tag_list_merge (const GstTagList * list1, const GstTagList * list2,
1163 GstTagMergeMode mode)
1165 GstTagList *list1_cp;
1166 const GstTagList *list2_cp;
1168 g_return_val_if_fail (list1 == NULL || GST_IS_TAG_LIST (list1), NULL);
1169 g_return_val_if_fail (list2 == NULL || GST_IS_TAG_LIST (list2), NULL);
1170 g_return_val_if_fail (GST_TAG_MODE_IS_VALID (mode), NULL);
1172 /* nothing to merge */
1173 if (!list1 && !list2) {
1177 /* create empty list, we need to do this to correctly handling merge modes */
1178 list1_cp = (list1) ? gst_tag_list_copy (list1) : gst_tag_list_new_empty ();
1179 list2_cp = (list2) ? list2 : gst_tag_list_new_empty ();
1181 gst_tag_list_insert (list1_cp, list2_cp, mode);
1184 gst_tag_list_unref ((GstTagList *) list2_cp);
1190 * gst_tag_list_get_tag_size:
1192 * @tag: the tag to query
1194 * Checks how many value are stored in this tag list for the given tag.
1196 * Returns: The number of tags stored
1199 gst_tag_list_get_tag_size (const GstTagList * list, const gchar * tag)
1201 const GValue *value;
1203 g_return_val_if_fail (GST_IS_TAG_LIST (list), 0);
1205 value = gst_structure_get_value (GST_TAG_LIST_STRUCTURE (list), tag);
1208 if (G_VALUE_TYPE (value) != GST_TYPE_LIST)
1211 return gst_value_list_get_size (value);
1216 * @list: list to set tags in
1217 * @mode: the mode to use
1219 * @...: %NULL-terminated list of values to set
1221 * Sets the values for the given tags using the specified mode.
1224 gst_tag_list_add (GstTagList * list, GstTagMergeMode mode, const gchar * tag,
1229 g_return_if_fail (GST_IS_TAG_LIST (list));
1230 g_return_if_fail (gst_tag_list_is_writable (list));
1231 g_return_if_fail (GST_TAG_MODE_IS_VALID (mode));
1232 g_return_if_fail (tag != NULL);
1234 va_start (args, tag);
1235 gst_tag_list_add_valist (list, mode, tag, args);
1240 * gst_tag_list_add_values:
1241 * @list: list to set tags in
1242 * @mode: the mode to use
1244 * @...: GValues to set
1246 * Sets the GValues for the given tags using the specified mode.
1249 gst_tag_list_add_values (GstTagList * list, GstTagMergeMode mode,
1250 const gchar * tag, ...)
1254 g_return_if_fail (GST_IS_TAG_LIST (list));
1255 g_return_if_fail (gst_tag_list_is_writable (list));
1256 g_return_if_fail (GST_TAG_MODE_IS_VALID (mode));
1257 g_return_if_fail (tag != NULL);
1259 va_start (args, tag);
1260 gst_tag_list_add_valist_values (list, mode, tag, args);
1265 * gst_tag_list_add_valist:
1266 * @list: list to set tags in
1267 * @mode: the mode to use
1269 * @var_args: tag / value pairs to set
1271 * Sets the values for the given tags using the specified mode.
1274 gst_tag_list_add_valist (GstTagList * list, GstTagMergeMode mode,
1275 const gchar * tag, va_list var_args)
1278 gchar *error = NULL;
1280 g_return_if_fail (GST_IS_TAG_LIST (list));
1281 g_return_if_fail (gst_tag_list_is_writable (list));
1282 g_return_if_fail (GST_TAG_MODE_IS_VALID (mode));
1283 g_return_if_fail (tag != NULL);
1285 if (mode == GST_TAG_MERGE_REPLACE_ALL) {
1286 gst_structure_remove_all_fields (GST_TAG_LIST_STRUCTURE (list));
1289 while (tag != NULL) {
1290 GValue value = { 0, };
1292 info = gst_tag_lookup (tag);
1293 if (G_UNLIKELY (info == NULL)) {
1294 g_warning ("unknown tag '%s'", tag);
1297 G_VALUE_COLLECT_INIT (&value, info->type, var_args, 0, &error);
1299 g_warning ("%s: %s", G_STRLOC, error);
1301 /* we purposely leak the value here, it might not be
1302 * in a sane state if an error condition occurred
1306 /* Facilitate GstBuffer -> GstSample transition */
1307 if (G_UNLIKELY (info->type == GST_TYPE_SAMPLE &&
1308 !GST_IS_SAMPLE (value.data[0].v_pointer))) {
1309 g_warning ("Expected GstSample argument for tag '%s'", tag);
1311 gst_tag_list_add_value_internal (list, mode, tag, &value, info);
1313 g_value_unset (&value);
1314 tag = va_arg (var_args, gchar *);
1319 * gst_tag_list_add_valist_values:
1320 * @list: list to set tags in
1321 * @mode: the mode to use
1323 * @var_args: tag / GValue pairs to set
1325 * Sets the GValues for the given tags using the specified mode.
1328 gst_tag_list_add_valist_values (GstTagList * list, GstTagMergeMode mode,
1329 const gchar * tag, va_list var_args)
1331 g_return_if_fail (GST_IS_TAG_LIST (list));
1332 g_return_if_fail (gst_tag_list_is_writable (list));
1333 g_return_if_fail (GST_TAG_MODE_IS_VALID (mode));
1334 g_return_if_fail (tag != NULL);
1336 if (mode == GST_TAG_MERGE_REPLACE_ALL) {
1337 gst_structure_remove_all_fields (GST_TAG_LIST_STRUCTURE (list));
1340 while (tag != NULL) {
1343 info = gst_tag_lookup (tag);
1344 if (G_UNLIKELY (info == NULL)) {
1345 g_warning ("unknown tag '%s'", tag);
1348 gst_tag_list_add_value_internal (list, mode, tag, va_arg (var_args,
1350 tag = va_arg (var_args, gchar *);
1355 * gst_tag_list_add_value:
1356 * @list: list to set tags in
1357 * @mode: the mode to use
1359 * @value: GValue for this tag
1361 * Sets the GValue for a given tag using the specified mode.
1364 gst_tag_list_add_value (GstTagList * list, GstTagMergeMode mode,
1365 const gchar * tag, const GValue * value)
1367 g_return_if_fail (GST_IS_TAG_LIST (list));
1368 g_return_if_fail (gst_tag_list_is_writable (list));
1369 g_return_if_fail (GST_TAG_MODE_IS_VALID (mode));
1370 g_return_if_fail (tag != NULL);
1372 gst_tag_list_add_value_internal (list, mode, tag, value, NULL);
1376 * gst_tag_list_remove_tag:
1377 * @list: list to remove tag from
1378 * @tag: tag to remove
1380 * Removes the given tag from the taglist.
1383 gst_tag_list_remove_tag (GstTagList * list, const gchar * tag)
1385 g_return_if_fail (GST_IS_TAG_LIST (list));
1386 g_return_if_fail (gst_tag_list_is_writable (list));
1387 g_return_if_fail (tag != NULL);
1389 gst_structure_remove_field (GST_TAG_LIST_STRUCTURE (list), tag);
1394 GstTagForeachFunc func;
1395 const GstTagList *tag_list;
1401 structure_foreach_wrapper (GQuark field_id, const GValue * value,
1404 TagForeachData *data = (TagForeachData *) user_data;
1406 data->func (data->tag_list, g_quark_to_string (field_id), data->data);
1411 * gst_tag_list_foreach:
1412 * @list: list to iterate over
1413 * @func: (scope call): function to be called for each tag
1414 * @user_data: (closure): user specified data
1416 * Calls the given function for each tag inside the tag list. Note that if there
1417 * is no tag, the function won't be called at all.
1420 gst_tag_list_foreach (const GstTagList * list, GstTagForeachFunc func,
1423 TagForeachData data;
1425 g_return_if_fail (GST_IS_TAG_LIST (list));
1426 g_return_if_fail (func != NULL);
1429 data.tag_list = list;
1430 data.data = user_data;
1431 gst_structure_foreach (GST_TAG_LIST_STRUCTURE (list),
1432 structure_foreach_wrapper, &data);
1436 * gst_tag_list_get_value_index:
1437 * @list: a #GstTagList
1438 * @tag: tag to read out
1439 * @index: number of entry to read out
1441 * Gets the value that is at the given index for the given tag in the given
1444 * Returns: (transfer none) (nullable): The GValue for the specified
1445 * entry or %NULL if the tag wasn't available or the tag
1446 * doesn't have as many entries
1449 gst_tag_list_get_value_index (const GstTagList * list, const gchar * tag,
1452 const GValue *value;
1454 g_return_val_if_fail (GST_IS_TAG_LIST (list), NULL);
1455 g_return_val_if_fail (tag != NULL, NULL);
1457 value = gst_structure_get_value (GST_TAG_LIST_STRUCTURE (list), tag);
1461 if (GST_VALUE_HOLDS_LIST (value)) {
1462 if (index >= gst_value_list_get_size (value))
1464 return gst_value_list_get_value (value, index);
1473 * gst_tag_list_copy_value:
1474 * @dest: (out caller-allocates): uninitialized #GValue to copy into
1475 * @list: list to get the tag from
1476 * @tag: tag to read out
1478 * Copies the contents for the given tag into the value,
1479 * merging multiple values into one if multiple values are associated
1481 * You must g_value_unset() the value after use.
1483 * Returns: %TRUE, if a value was copied, %FALSE if the tag didn't exist in the
1487 gst_tag_list_copy_value (GValue * dest, const GstTagList * list,
1492 g_return_val_if_fail (GST_IS_TAG_LIST (list), FALSE);
1493 g_return_val_if_fail (tag != NULL, FALSE);
1494 g_return_val_if_fail (dest != NULL, FALSE);
1495 g_return_val_if_fail (G_VALUE_TYPE (dest) == 0, FALSE);
1497 src = gst_structure_get_value (GST_TAG_LIST_STRUCTURE (list), tag);
1501 if (G_VALUE_TYPE (src) == GST_TYPE_LIST) {
1502 GstTagInfo *info = gst_tag_lookup (tag);
1507 /* must be there or lists aren't allowed */
1508 g_assert (info->merge_func);
1509 info->merge_func (dest, src);
1511 g_value_init (dest, G_VALUE_TYPE (src));
1512 g_value_copy (src, dest);
1517 /* FIXME 2.0: this whole merge function business is overdesigned, and the
1518 * _get_foo() API is misleading as well - how many application developers will
1519 * expect gst_tag_list_get_string (list, GST_TAG_ARTIST, &val) might return a
1520 * string with multiple comma-separated artists? _get_foo() should just be
1521 * a convenience wrapper around _get_foo_index (list, tag, 0, &val),
1522 * supplemented by a special _tag_list_get_string_merged() function if needed
1523 * (unless someone can actually think of real use cases where the merge
1524 * function is not 'use first' for non-strings and merge for strings) */
1526 /***** evil macros to get all the gst_tag_list_get_*() functions right *****/
1528 #define TAG_MERGE_FUNCS(name,type,ret) \
1530 gst_tag_list_get_ ## name (const GstTagList *list, const gchar *tag, \
1533 GValue v = { 0, }; \
1535 g_return_val_if_fail (GST_IS_TAG_LIST (list), FALSE); \
1536 g_return_val_if_fail (tag != NULL, FALSE); \
1537 g_return_val_if_fail (value != NULL, FALSE); \
1539 if (!gst_tag_list_copy_value (&v, list, tag)) \
1541 *value = COPY_FUNC (g_value_get_ ## name (&v)); \
1542 g_value_unset (&v); \
1547 gst_tag_list_get_ ## name ## _index (const GstTagList *list, \
1549 guint index, type *value) \
1553 g_return_val_if_fail (GST_IS_TAG_LIST (list), FALSE); \
1554 g_return_val_if_fail (tag != NULL, FALSE); \
1555 g_return_val_if_fail (value != NULL, FALSE); \
1557 if ((v = gst_tag_list_get_value_index (list, tag, index)) == NULL) \
1559 *value = COPY_FUNC (g_value_get_ ## name (v)); \
1563 #define COPY_FUNC /**/
1565 * gst_tag_list_get_boolean:
1566 * @list: a #GstTagList to get the tag from
1567 * @tag: tag to read out
1568 * @value: (out): location for the result
1570 * Copies the contents for the given tag into the value, merging multiple values
1571 * into one if multiple values are associated with the tag.
1573 * Returns: %TRUE, if a value was copied, %FALSE if the tag didn't exist in the
1577 * gst_tag_list_get_boolean_index:
1578 * @list: a #GstTagList to get the tag from
1579 * @tag: tag to read out
1580 * @index: number of entry to read out
1581 * @value: (out): location for the result
1583 * Gets the value that is at the given index for the given tag in the given
1586 * Returns: %TRUE, if a value was copied, %FALSE if the tag didn't exist in the
1589 TAG_MERGE_FUNCS (boolean, gboolean, TRUE);
1591 * gst_tag_list_get_int:
1592 * @list: a #GstTagList to get the tag from
1593 * @tag: tag to read out
1594 * @value: (out): location for the result
1596 * Copies the contents for the given tag into the value, merging multiple values
1597 * into one if multiple values are associated with the tag.
1599 * Returns: %TRUE, if a value was copied, %FALSE if the tag didn't exist in the
1603 * gst_tag_list_get_int_index:
1604 * @list: a #GstTagList to get the tag from
1605 * @tag: tag to read out
1606 * @index: number of entry to read out
1607 * @value: (out): location for the result
1609 * Gets the value that is at the given index for the given tag in the given
1612 * Returns: %TRUE, if a value was copied, %FALSE if the tag didn't exist in the
1615 TAG_MERGE_FUNCS (int, gint, TRUE);
1617 * gst_tag_list_get_uint:
1618 * @list: a #GstTagList to get the tag from
1619 * @tag: tag to read out
1620 * @value: (out): location for the result
1622 * Copies the contents for the given tag into the value, merging multiple values
1623 * into one if multiple values are associated with the tag.
1625 * Returns: %TRUE, if a value was copied, %FALSE if the tag didn't exist in the
1629 * gst_tag_list_get_uint_index:
1630 * @list: a #GstTagList to get the tag from
1631 * @tag: tag to read out
1632 * @index: number of entry to read out
1633 * @value: (out): location for the result
1635 * Gets the value that is at the given index for the given tag in the given
1638 * Returns: %TRUE, if a value was copied, %FALSE if the tag didn't exist in the
1641 TAG_MERGE_FUNCS (uint, guint, TRUE);
1643 * gst_tag_list_get_int64:
1644 * @list: a #GstTagList to get the tag from
1645 * @tag: tag to read out
1646 * @value: (out): location for the result
1648 * Copies the contents for the given tag into the value, merging multiple values
1649 * into one if multiple values are associated with the tag.
1651 * Returns: %TRUE, if a value was copied, %FALSE if the tag didn't exist in the
1655 * gst_tag_list_get_int64_index:
1656 * @list: a #GstTagList to get the tag from
1657 * @tag: tag to read out
1658 * @index: number of entry to read out
1659 * @value: (out): location for the result
1661 * Gets the value that is at the given index for the given tag in the given
1664 * Returns: %TRUE, if a value was copied, %FALSE if the tag didn't exist in the
1667 TAG_MERGE_FUNCS (int64, gint64, TRUE);
1669 * gst_tag_list_get_uint64:
1670 * @list: a #GstTagList to get the tag from
1671 * @tag: tag to read out
1672 * @value: (out): location for the result
1674 * Copies the contents for the given tag into the value, merging multiple values
1675 * into one if multiple values are associated with the tag.
1677 * Returns: %TRUE, if a value was copied, %FALSE if the tag didn't exist in the
1681 * gst_tag_list_get_uint64_index:
1682 * @list: a #GstTagList to get the tag from
1683 * @tag: tag to read out
1684 * @index: number of entry to read out
1685 * @value: (out): location for the result
1687 * Gets the value that is at the given index for the given tag in the given
1690 * Returns: %TRUE, if a value was copied, %FALSE if the tag didn't exist in the
1693 TAG_MERGE_FUNCS (uint64, guint64, TRUE);
1695 * gst_tag_list_get_float:
1696 * @list: a #GstTagList to get the tag from
1697 * @tag: tag to read out
1698 * @value: (out): location for the result
1700 * Copies the contents for the given tag into the value, merging multiple values
1701 * into one if multiple values are associated with the tag.
1703 * Returns: %TRUE, if a value was copied, %FALSE if the tag didn't exist in the
1707 * gst_tag_list_get_float_index:
1708 * @list: a #GstTagList to get the tag from
1709 * @tag: tag to read out
1710 * @index: number of entry to read out
1711 * @value: (out): location for the result
1713 * Gets the value that is at the given index for the given tag in the given
1716 * Returns: %TRUE, if a value was copied, %FALSE if the tag didn't exist in the
1719 TAG_MERGE_FUNCS (float, gfloat, TRUE);
1721 * gst_tag_list_get_double:
1722 * @list: a #GstTagList to get the tag from
1723 * @tag: tag to read out
1724 * @value: (out): location for the result
1726 * Copies the contents for the given tag into the value, merging multiple values
1727 * into one if multiple values are associated with the tag.
1729 * Returns: %TRUE, if a value was copied, %FALSE if the tag didn't exist in the
1733 * gst_tag_list_get_double_index:
1734 * @list: a #GstTagList to get the tag from
1735 * @tag: tag to read out
1736 * @index: number of entry to read out
1737 * @value: (out): location for the result
1739 * Gets the value that is at the given index for the given tag in the given
1742 * Returns: %TRUE, if a value was copied, %FALSE if the tag didn't exist in the
1745 TAG_MERGE_FUNCS (double, gdouble, TRUE);
1747 * gst_tag_list_get_pointer:
1748 * @list: a #GstTagList to get the tag from
1749 * @tag: tag to read out
1750 * @value: (out) (transfer none): location for the result
1752 * Copies the contents for the given tag into the value, merging multiple values
1753 * into one if multiple values are associated with the tag.
1755 * Returns: %TRUE, if a value was copied, %FALSE if the tag didn't exist in the
1759 * gst_tag_list_get_pointer_index:
1760 * @list: a #GstTagList to get the tag from
1761 * @tag: tag to read out
1762 * @index: number of entry to read out
1763 * @value: (out) (transfer none): location for the result
1765 * Gets the value that is at the given index for the given tag in the given
1768 * Returns: %TRUE, if a value was copied, %FALSE if the tag didn't exist in the
1771 TAG_MERGE_FUNCS (pointer, gpointer, (*value != NULL));
1773 static inline gchar *
1774 _gst_strdup0 (const gchar * s)
1776 if (s == NULL || *s == '\0')
1779 return g_strdup (s);
1783 #define COPY_FUNC _gst_strdup0
1786 * gst_tag_list_get_string:
1787 * @list: a #GstTagList to get the tag from
1788 * @tag: tag to read out
1789 * @value: (out callee-allocates) (transfer full): location for the result
1791 * Copies the contents for the given tag into the value, possibly merging
1792 * multiple values into one if multiple values are associated with the tag.
1794 * Use gst_tag_list_get_string_index (list, tag, 0, value) if you want
1795 * to retrieve the first string associated with this tag unmodified.
1797 * The resulting string in @value will be in UTF-8 encoding and should be
1798 * freed by the caller using g_free when no longer needed. The
1799 * returned string is also guaranteed to be non-%NULL and non-empty.
1801 * Free-function: g_free
1803 * Returns: %TRUE, if a value was copied, %FALSE if the tag didn't exist in the
1807 * gst_tag_list_get_string_index:
1808 * @list: a #GstTagList to get the tag from
1809 * @tag: tag to read out
1810 * @index: number of entry to read out
1811 * @value: (out callee-allocates) (transfer full): location for the result
1813 * Gets the value that is at the given index for the given tag in the given
1816 * The resulting string in @value will be in UTF-8 encoding and should be
1817 * freed by the caller using g_free when no longer needed. The
1818 * returned string is also guaranteed to be non-%NULL and non-empty.
1820 * Free-function: g_free
1822 * Returns: %TRUE, if a value was copied, %FALSE if the tag didn't exist in the
1825 TAG_MERGE_FUNCS (string, gchar *, (*value != NULL));
1828 *FIXME 2.0: Instead of _peek (non-copy) and _get (copy), we could have
1829 * _get (non-copy) and _dup (copy) for strings, seems more
1833 * gst_tag_list_peek_string_index:
1834 * @list: a #GstTagList to get the tag from
1835 * @tag: tag to read out
1836 * @index: number of entry to read out
1837 * @value: (out) (transfer none): location for the result
1839 * Peeks at the value that is at the given index for the given tag in the given
1842 * The resulting string in @value will be in UTF-8 encoding and doesn't need
1843 * to be freed by the caller. The returned string is also guaranteed to
1844 * be non-%NULL and non-empty.
1846 * Returns: %TRUE, if a value was set, %FALSE if the tag didn't exist in the
1850 gst_tag_list_peek_string_index (const GstTagList * list,
1851 const gchar * tag, guint index, const gchar ** value)
1855 g_return_val_if_fail (GST_IS_TAG_LIST (list), FALSE);
1856 g_return_val_if_fail (tag != NULL, FALSE);
1857 g_return_val_if_fail (value != NULL, FALSE);
1859 if ((v = gst_tag_list_get_value_index (list, tag, index)) == NULL)
1861 *value = g_value_get_string (v);
1862 return *value != NULL && **value != '\0';
1866 * gst_tag_list_get_date:
1867 * @list: a #GstTagList to get the tag from
1868 * @tag: tag to read out
1869 * @value: (out callee-allocates) (transfer full): address of a GDate pointer
1870 * variable to store the result into
1872 * Copies the first date for the given tag in the taglist into the variable
1873 * pointed to by @value. Free the date with g_date_free() when it is no longer
1876 * Free-function: g_date_free
1878 * Returns: %TRUE, if a date was copied, %FALSE if the tag didn't exist in the
1879 * given list or if it was %NULL.
1882 gst_tag_list_get_date (const GstTagList * list, const gchar * tag,
1887 g_return_val_if_fail (GST_IS_TAG_LIST (list), FALSE);
1888 g_return_val_if_fail (tag != NULL, FALSE);
1889 g_return_val_if_fail (value != NULL, FALSE);
1891 if (!gst_tag_list_copy_value (&v, list, tag))
1893 *value = (GDate *) g_value_dup_boxed (&v);
1895 return (*value != NULL);
1899 * gst_tag_list_get_date_index:
1900 * @list: a #GstTagList to get the tag from
1901 * @tag: tag to read out
1902 * @index: number of entry to read out
1903 * @value: (out callee-allocates) (transfer full): location for the result
1905 * Gets the date that is at the given index for the given tag in the given
1906 * list and copies it into the variable pointed to by @value. Free the date
1907 * with g_date_free() when it is no longer needed.
1909 * Free-function: g_date_free
1911 * Returns: %TRUE, if a value was copied, %FALSE if the tag didn't exist in the
1912 * given list or if it was %NULL.
1915 gst_tag_list_get_date_index (const GstTagList * list,
1916 const gchar * tag, guint index, GDate ** value)
1920 g_return_val_if_fail (GST_IS_TAG_LIST (list), FALSE);
1921 g_return_val_if_fail (tag != NULL, FALSE);
1922 g_return_val_if_fail (value != NULL, FALSE);
1924 if ((v = gst_tag_list_get_value_index (list, tag, index)) == NULL)
1926 *value = (GDate *) g_value_dup_boxed (v);
1927 return (*value != NULL);
1931 * gst_tag_list_get_date_time:
1932 * @list: a #GstTagList to get the tag from
1933 * @tag: tag to read out
1934 * @value: (out callee-allocates) (transfer full): address of a #GstDateTime
1935 * pointer variable to store the result into
1937 * Copies the first datetime for the given tag in the taglist into the variable
1938 * pointed to by @value. Unref the date with gst_date_time_unref() when
1939 * it is no longer needed.
1941 * Free-function: gst_date_time_unref
1943 * Returns: %TRUE, if a datetime was copied, %FALSE if the tag didn't exist in
1944 * the given list or if it was %NULL.
1947 gst_tag_list_get_date_time (const GstTagList * list, const gchar * tag,
1948 GstDateTime ** value)
1952 g_return_val_if_fail (GST_IS_TAG_LIST (list), FALSE);
1953 g_return_val_if_fail (tag != NULL, FALSE);
1954 g_return_val_if_fail (value != NULL, FALSE);
1956 if (!gst_tag_list_copy_value (&v, list, tag))
1959 *value = (GstDateTime *) g_value_dup_boxed (&v);
1961 return (*value != NULL);
1965 * gst_tag_list_get_date_time_index:
1966 * @list: a #GstTagList to get the tag from
1967 * @tag: tag to read out
1968 * @index: number of entry to read out
1969 * @value: (out callee-allocates) (transfer full): location for the result
1971 * Gets the datetime that is at the given index for the given tag in the given
1972 * list and copies it into the variable pointed to by @value. Unref the datetime
1973 * with gst_date_time_unref() when it is no longer needed.
1975 * Free-function: gst_date_time_unref
1977 * Returns: %TRUE, if a value was copied, %FALSE if the tag didn't exist in the
1978 * given list or if it was %NULL.
1981 gst_tag_list_get_date_time_index (const GstTagList * list,
1982 const gchar * tag, guint index, GstDateTime ** value)
1986 g_return_val_if_fail (GST_IS_TAG_LIST (list), FALSE);
1987 g_return_val_if_fail (tag != NULL, FALSE);
1988 g_return_val_if_fail (value != NULL, FALSE);
1990 if ((v = gst_tag_list_get_value_index (list, tag, index)) == NULL)
1992 *value = (GstDateTime *) g_value_dup_boxed (v);
1993 return (*value != NULL);
1997 * gst_tag_list_get_sample:
1998 * @list: a #GstTagList to get the tag from
1999 * @tag: tag to read out
2000 * @sample: (out callee-allocates) (transfer full): address of a GstSample
2001 * pointer variable to store the result into
2003 * Copies the first sample for the given tag in the taglist into the variable
2004 * pointed to by @sample. Free the sample with gst_sample_unref() when it is
2005 * no longer needed. You can retrieve the buffer from the sample using
2006 * gst_sample_get_buffer() and the associated caps (if any) with
2007 * gst_sample_get_caps().
2009 * Free-function: gst_sample_unref
2011 * Returns: %TRUE, if a sample was returned, %FALSE if the tag didn't exist in
2012 * the given list or if it was %NULL.
2015 gst_tag_list_get_sample (const GstTagList * list, const gchar * tag,
2016 GstSample ** sample)
2020 g_return_val_if_fail (GST_IS_TAG_LIST (list), FALSE);
2021 g_return_val_if_fail (tag != NULL, FALSE);
2022 g_return_val_if_fail (sample != NULL, FALSE);
2024 if (!gst_tag_list_copy_value (&v, list, tag))
2026 *sample = g_value_dup_boxed (&v);
2028 return (*sample != NULL);
2032 * gst_tag_list_get_sample_index:
2033 * @list: a #GstTagList to get the tag from
2034 * @tag: tag to read out
2035 * @index: number of entry to read out
2036 * @sample: (out callee-allocates) (transfer full): address of a GstSample
2037 * pointer variable to store the result into
2039 * Gets the sample that is at the given index for the given tag in the given
2040 * list and copies it into the variable pointed to by @sample. Free the sample
2041 * with gst_sample_unref() when it is no longer needed. You can retrieve the
2042 * buffer from the sample using gst_sample_get_buffer() and the associated
2043 * caps (if any) with gst_sample_get_caps().
2045 * Free-function: gst_sample_unref
2047 * Returns: %TRUE, if a sample was copied, %FALSE if the tag didn't exist in the
2048 * given list or if it was %NULL.
2051 gst_tag_list_get_sample_index (const GstTagList * list,
2052 const gchar * tag, guint index, GstSample ** sample)
2056 g_return_val_if_fail (GST_IS_TAG_LIST (list), FALSE);
2057 g_return_val_if_fail (tag != NULL, FALSE);
2058 g_return_val_if_fail (sample != NULL, FALSE);
2060 if ((v = gst_tag_list_get_value_index (list, tag, index)) == NULL)
2062 *sample = g_value_dup_boxed (v);
2063 return (*sample != NULL);
2067 * gst_tag_list_copy:
2068 * @taglist: a #GstTagList.
2070 * Creates a new #GstTagList as a copy of the old @taglist. The new taglist
2071 * will have a refcount of 1, owned by the caller, and will be writable as
2074 * Note that this function is the semantic equivalent of a gst_tag_list_ref()
2075 * followed by a gst_tag_list_make_writable(). If you only want to hold on to a
2076 * reference to the data, you should use gst_tag_list_ref().
2078 * When you are finished with the taglist, call gst_tag_list_unref() on it.
2080 * Returns: (transfer full): the new #GstTagList
2082 GstTagList *(gst_tag_list_copy) (const GstTagList * taglist)
2084 return GST_TAG_LIST (gst_mini_object_copy (GST_MINI_OBJECT_CAST (taglist)));
2088 * gst_tag_list_ref: (skip)
2089 * @taglist: the #GstTagList to reference
2091 * Add a reference to a #GstTagList mini object.
2093 * From this point on, until the caller calls gst_tag_list_unref() or
2094 * gst_tag_list_make_writable(), it is guaranteed that the taglist object will
2095 * not change. To use a #GstTagList object, you must always have a refcount on
2096 * it -- either the one made implicitly by e.g. gst_tag_list_new(), or via
2097 * taking one explicitly with this function.
2099 * Returns: the same #GstTagList mini object.
2102 gst_tag_list_ref (GstTagList * taglist)
2104 return (GstTagList *) gst_mini_object_ref (GST_MINI_OBJECT_CAST (taglist));
2108 * gst_tag_list_unref: (skip)
2109 * @taglist: a #GstTagList.
2111 * Unref a #GstTagList, and and free all its memory when the refcount reaches 0.
2114 gst_tag_list_unref (GstTagList * taglist)
2116 gst_mini_object_unref (GST_MINI_OBJECT_CAST (taglist));
2120 * gst_clear_tag_list: (skip)
2121 * @taglist_ptr: a pointer to a #GstTagList reference
2123 * Clears a reference to a #GstTagList.
2125 * @taglist_ptr must not be %NULL.
2127 * If the reference is %NULL then this function does nothing. Otherwise, the
2128 * reference count of the taglist is decreased and the pointer is set to %NULL.
2133 gst_clear_tag_list (GstTagList ** taglist_ptr)
2135 gst_clear_mini_object ((GstMiniObject **) taglist_ptr);
2139 * gst_tag_list_replace:
2140 * @old_taglist: (inout) (transfer full) (nullable): pointer to a pointer to a
2141 * #GstTagList to be replaced.
2142 * @new_taglist: (transfer none) (allow-none): pointer to a #GstTagList that
2143 * will replace the tag list pointed to by @old_taglist.
2145 * Modifies a pointer to a #GstTagList to point to a different #GstTagList. The
2146 * modification is done atomically (so this is useful for ensuring thread
2147 * safety in some cases), and the reference counts are updated appropriately
2148 * (the old tag list is unreffed, the new is reffed).
2150 * Either @new_taglist or the #GstTagList pointed to by @old_taglist may be
2153 * Returns: %TRUE if @new_taglist was different from @old_taglist
2158 gst_tag_list_replace (GstTagList ** old_taglist, GstTagList * new_taglist)
2160 return gst_mini_object_replace ((GstMiniObject **) old_taglist,
2161 (GstMiniObject *) new_taglist);
2165 * gst_tag_list_take:
2166 * @old_taglist: (inout) (transfer full): pointer to a pointer to a #GstTagList
2168 * @new_taglist: (transfer full) (allow-none): pointer to a #GstTagList that
2169 * will replace the taglist pointed to by @old_taglist.
2171 * Modifies a pointer to a #GstTagList to point to a different #GstTagList.
2172 * This function is similar to gst_tag_list_replace() except that it takes
2173 * ownership of @new_taglist.
2175 * Returns: %TRUE if @new_taglist was different from @old_taglist
2180 gst_tag_list_take (GstTagList ** old_taglist, GstTagList * new_taglist)
2182 return gst_mini_object_take ((GstMiniObject **) old_taglist,
2183 (GstMiniObject *) new_taglist);