2 * Copyright (C) <2003> David A. Schleef <ds@schleef.org>
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Library General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Library General Public License for more details.
14 * You should have received a copy of the GNU Library General Public
15 * License along with this library; if not, write to the
16 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 * Boston, MA 02111-1307, USA.
22 * @short_description: Structure describing sets of media formats
23 * @see_also: #GstStructure
25 * Caps (capabilities) are lighweight refcounted objects describing media types.
26 * They are composed of an array of #GstStructure.
28 * Caps are exposed on #GstPadTemplate to describe all possible types a
29 * given pad can handle. They are also stored in the #GstRegistry along with
30 * a description of the #GstElement.
32 * Caps are exposed on the element pads using the gst_pad_get_caps() pad
33 * function. This function describes the possible types that the pad can
34 * handle or produce at runtime.
36 * Caps are also attached to buffers to describe to content of the data
37 * pointed to by the buffer with gst_buffer_set_caps(). Caps attached to
38 * a #GstBuffer allow for format negotiation upstream and downstream.
40 * A #GstCaps can be constructed with the following code fragment:
43 * <title>Creating caps</title>
46 * caps = gst_caps_new_simple ("video/x-raw-yuv",
47 * "format", GST_TYPE_FOURCC, GST_MAKE_FOURCC ('I', '4', '2', '0'),
48 * "framerate", GST_TYPE_FRACTION, 25, 1,
49 * "pixel-aspect-ratio", GST_TYPE_FRACTION, 1, 1,
50 * "width", G_TYPE_INT, 320,
51 * "height", G_TYPE_INT, 240,
56 * A #GstCaps is fixed when it has no properties with ranges or lists. Use
57 * gst_caps_is_fixed() to test for fixed caps. Only fixed caps can be
58 * set on a #GstPad or #GstBuffer.
60 * Various methods exist to work with the media types such as subtracting
63 * Last reviewed on 2007-02-13 (0.10.10)
72 #include "gst_private.h"
74 #include <gobject/gvaluecollector.h>
76 #ifdef GST_DISABLE_DEPRECATED
77 #if !defined(GST_DISABLE_LOADSAVE) && !defined(GST_REMOVE_DEPRECATED)
78 #include <libxml/parser.h>
79 xmlNodePtr gst_caps_save_thyself (const GstCaps * caps, xmlNodePtr parent);
80 GstCaps *gst_caps_load_thyself (xmlNodePtr parent);
84 #define DEBUG_REFCOUNT
86 #define CAPS_POISON(caps) G_STMT_START{ \
88 GstCaps *_newcaps = gst_caps_copy (caps); \
89 gst_caps_unref(caps); \
93 #define STRUCTURE_POISON(structure) G_STMT_START{ \
95 GstStructure *_newstruct = gst_structure_copy (structure); \
96 gst_structure_free(structure); \
97 structure = _newstruct; \
100 #define IS_WRITABLE(caps) \
101 (g_atomic_int_get (&(caps)->refcount) == 1)
103 /* same as gst_caps_is_any () */
104 #define CAPS_IS_ANY(caps) \
105 ((caps)->flags & GST_CAPS_FLAGS_ANY)
107 /* same as gst_caps_is_empty () */
108 #define CAPS_IS_EMPTY(caps) \
109 (!CAPS_IS_ANY(caps) && CAPS_IS_EMPTY_SIMPLE(caps))
111 #define CAPS_IS_EMPTY_SIMPLE(caps) \
112 (((caps)->structs == NULL) || ((caps)->structs->len == 0))
114 /* quick way to get a caps structure at an index without doing a type or array
116 #define gst_caps_get_structure_unchecked(caps, index) \
117 ((GstStructure *)g_ptr_array_index ((caps)->structs, (index)))
118 /* quick way to append a structure without checking the args */
119 #define gst_caps_append_structure_unchecked(caps, structure) G_STMT_START{\
120 GstStructure *__s=structure; \
121 gst_structure_set_parent_refcount (__s, &caps->refcount); \
122 g_ptr_array_add (caps->structs, __s); \
125 /* lock to protect multiple invocations of static caps to caps conversion */
126 G_LOCK_DEFINE_STATIC (static_caps_lock);
128 static void gst_caps_transform_to_string (const GValue * src_value,
129 GValue * dest_value);
130 static gboolean gst_caps_from_string_inplace (GstCaps * caps,
131 const gchar * string);
132 static GstCaps *gst_caps_copy_conditional (GstCaps * src);
135 gst_caps_get_type (void)
137 static GType gst_caps_type = 0;
139 if (G_UNLIKELY (gst_caps_type == 0)) {
140 gst_caps_type = g_boxed_type_register_static ("GstCaps",
141 (GBoxedCopyFunc) gst_caps_copy_conditional,
142 (GBoxedFreeFunc) gst_caps_unref);
144 g_value_register_transform_func (gst_caps_type,
145 G_TYPE_STRING, gst_caps_transform_to_string);
148 return gst_caps_type;
151 /* creation/deletion */
154 * gst_caps_new_empty:
156 * Creates a new #GstCaps that is empty. That is, the returned
157 * #GstCaps contains no media formats.
158 * Caller is responsible for unreffing the returned caps.
160 * Returns: (transfer full): the new #GstCaps
163 gst_caps_new_empty (void)
165 GstCaps *caps = g_slice_new (GstCaps);
167 caps->type = GST_TYPE_CAPS;
170 caps->structs = g_ptr_array_new ();
171 /* the 32 has been determined by logging caps sizes in _gst_caps_free
172 * but g_ptr_array uses 16 anyway if it expands once, so this does not help
174 * caps->structs = g_ptr_array_sized_new (32);
177 #ifdef DEBUG_REFCOUNT
178 GST_CAT_LOG (GST_CAT_CAPS, "created caps %p", caps);
187 * Creates a new #GstCaps that indicates that it is compatible with
190 * Returns: (transfer full): the new #GstCaps
193 gst_caps_new_any (void)
195 GstCaps *caps = gst_caps_new_empty ();
197 caps->flags = GST_CAPS_FLAGS_ANY;
203 * gst_caps_new_simple:
204 * @media_type: the media type of the structure
205 * @fieldname: first field to set
206 * @...: additional arguments
208 * Creates a new #GstCaps that contains one #GstStructure. The
209 * structure is defined by the arguments, which have the same format
210 * as gst_structure_new().
211 * Caller is responsible for unreffing the returned caps.
213 * Returns: (transfer full): the new #GstCaps
216 gst_caps_new_simple (const char *media_type, const char *fieldname, ...)
219 GstStructure *structure;
222 caps = gst_caps_new_empty ();
224 va_start (var_args, fieldname);
225 structure = gst_structure_new_valist (media_type, fieldname, var_args);
228 gst_caps_append_structure_unchecked (caps, structure);
235 * @struct1: the first structure to add
236 * @...: additional structures to add
238 * Creates a new #GstCaps and adds all the structures listed as
239 * arguments. The list must be NULL-terminated. The structures
240 * are not copied; the returned #GstCaps owns the structures.
242 * Returns: (transfer full): the new #GstCaps
245 gst_caps_new_full (GstStructure * struct1, ...)
250 va_start (var_args, struct1);
251 caps = gst_caps_new_full_valist (struct1, var_args);
258 * gst_caps_new_full_valist:
259 * @structure: the first structure to add
260 * @var_args: additional structures to add
262 * Creates a new #GstCaps and adds all the structures listed as
263 * arguments. The list must be NULL-terminated. The structures
264 * are not copied; the returned #GstCaps owns the structures.
266 * Returns: (transfer full): the new #GstCaps
269 gst_caps_new_full_valist (GstStructure * structure, va_list var_args)
273 caps = gst_caps_new_empty ();
276 gst_caps_append_structure_unchecked (caps, structure);
277 structure = va_arg (var_args, GstStructure *);
285 * @caps: the #GstCaps to copy
287 * Creates a new #GstCaps as a copy of the old @caps. The new caps will have a
288 * refcount of 1, owned by the caller. The structures are copied as well.
290 * Note that this function is the semantic equivalent of a gst_caps_ref()
291 * followed by a gst_caps_make_writable(). If you only want to hold on to a
292 * reference to the data, you should use gst_caps_ref().
294 * When you are finished with the caps, call gst_caps_unref() on it.
296 * Returns: (transfer full): the new #GstCaps
299 gst_caps_copy (const GstCaps * caps)
302 GstStructure *structure;
305 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
307 newcaps = gst_caps_new_empty ();
308 newcaps->flags = caps->flags;
309 n = caps->structs->len;
311 for (i = 0; i < n; i++) {
312 structure = gst_caps_get_structure_unchecked (caps, i);
313 gst_caps_append_structure_unchecked (newcaps,
314 gst_structure_copy (structure));
321 _gst_caps_free (GstCaps * caps)
323 GstStructure *structure;
326 /* The refcount must be 0, but since we're only called by gst_caps_unref,
327 * don't bother testing. */
328 len = caps->structs->len;
329 /* This can be used to get statistics about caps sizes */
330 /*GST_CAT_INFO (GST_CAT_CAPS, "caps size: %d", len); */
331 for (i = 0; i < len; i++) {
332 structure = (GstStructure *) gst_caps_get_structure_unchecked (caps, i);
333 gst_structure_set_parent_refcount (structure, NULL);
334 gst_structure_free (structure);
336 g_ptr_array_free (caps->structs, TRUE);
338 memset (caps, 0xff, sizeof (GstCaps));
341 #ifdef DEBUG_REFCOUNT
342 GST_CAT_LOG (GST_CAT_CAPS, "freeing caps %p", caps);
344 g_slice_free (GstCaps, caps);
348 * gst_caps_make_writable:
349 * @caps: (transfer full): the #GstCaps to make writable
351 * Returns a writable copy of @caps.
353 * If there is only one reference count on @caps, the caller must be the owner,
354 * and so this function will return the caps object unchanged. If on the other
355 * hand there is more than one reference on the object, a new caps object will
356 * be returned. The caller's reference on @caps will be removed, and instead the
357 * caller will own a reference to the returned object.
359 * In short, this function unrefs the caps in the argument and refs the caps
360 * that it returns. Don't access the argument after calling this function. See
361 * also: gst_caps_ref().
363 * Returns: (transfer full): the same #GstCaps object.
366 gst_caps_make_writable (GstCaps * caps)
370 g_return_val_if_fail (caps != NULL, NULL);
372 /* we are the only instance reffing this caps */
373 if (IS_WRITABLE (caps))
377 GST_CAT_DEBUG (GST_CAT_PERFORMANCE, "copy caps");
378 copy = gst_caps_copy (caps);
379 gst_caps_unref (caps);
386 * @caps: the #GstCaps to reference
388 * Add a reference to a #GstCaps object.
390 * From this point on, until the caller calls gst_caps_unref() or
391 * gst_caps_make_writable(), it is guaranteed that the caps object will not
392 * change. This means its structures won't change, etc. To use a #GstCaps
393 * object, you must always have a refcount on it -- either the one made
394 * implicitly by e.g. gst_caps_new_simple(), or via taking one explicitly with
397 * Returns: (transfer full): the same #GstCaps object.
400 gst_caps_ref (GstCaps * caps)
402 g_return_val_if_fail (caps != NULL, NULL);
404 #ifdef DEBUG_REFCOUNT
405 GST_CAT_TRACE (GST_CAT_REFCOUNTING, "%p %d->%d", caps,
406 GST_CAPS_REFCOUNT_VALUE (caps), GST_CAPS_REFCOUNT_VALUE (caps) + 1);
408 g_return_val_if_fail (GST_CAPS_REFCOUNT_VALUE (caps), NULL);
410 g_atomic_int_inc (&caps->refcount);
417 * @caps: (transfer full): the #GstCaps to unref
419 * Unref a #GstCaps and and free all its structures and the
420 * structures' values when the refcount reaches 0.
423 gst_caps_unref (GstCaps * caps)
425 g_return_if_fail (caps != NULL);
427 #ifdef DEBUG_REFCOUNT
428 GST_CAT_TRACE (GST_CAT_REFCOUNTING, "%p %d->%d", caps,
429 GST_CAPS_REFCOUNT_VALUE (caps), GST_CAPS_REFCOUNT_VALUE (caps) - 1);
432 g_return_if_fail (GST_CAPS_REFCOUNT_VALUE (caps));
434 /* if we ended up with the refcount at zero, free the caps */
435 if (G_UNLIKELY (g_atomic_int_dec_and_test (&caps->refcount)))
436 _gst_caps_free (caps);
440 gst_static_caps_get_type (void)
442 static GType staticcaps_type = 0;
444 if (G_UNLIKELY (staticcaps_type == 0)) {
445 staticcaps_type = g_pointer_type_register_static ("GstStaticCaps");
447 return staticcaps_type;
452 * gst_static_caps_get:
453 * @static_caps: the #GstStaticCaps to convert
455 * Converts a #GstStaticCaps to a #GstCaps.
457 * Returns: (transfer full): a pointer to the #GstCaps. Unref after usage.
458 * Since the core holds an additional ref to the returned caps,
459 * use gst_caps_make_writable() on the returned caps to modify it.
462 gst_static_caps_get (GstStaticCaps * static_caps)
466 g_return_val_if_fail (static_caps != NULL, NULL);
468 caps = (GstCaps *) static_caps;
470 /* refcount is 0 when we need to convert */
471 if (G_UNLIKELY (g_atomic_int_get (&caps->refcount) == 0)) {
475 G_LOCK (static_caps_lock);
476 /* check if other thread already updated */
477 if (G_UNLIKELY (g_atomic_int_get (&caps->refcount)))
480 string = static_caps->string;
482 if (G_UNLIKELY (string == NULL))
485 GST_CAT_LOG (GST_CAT_CAPS, "creating %p", static_caps);
487 /* we construct the caps on the stack, then copy over the struct into our
488 * real caps, refcount last. We do this because we must leave the refcount
489 * of the result caps to 0 so that other threads don't run away with the
490 * caps while we are constructing it. */
491 temp.type = GST_TYPE_CAPS;
493 temp.structs = g_ptr_array_new ();
495 /* initialize the caps to a refcount of 1 so the caps can be writable for
496 * the next statement */
499 /* convert to string */
500 if (G_UNLIKELY (!gst_caps_from_string_inplace (&temp, string)))
501 g_critical ("Could not convert static caps \"%s\"", string);
503 /* now copy stuff over to the real caps. */
504 caps->type = temp.type;
505 caps->flags = temp.flags;
506 caps->structs = temp.structs;
507 /* and bump the refcount so other threads can now read */
508 g_atomic_int_set (&caps->refcount, 1);
510 GST_CAT_LOG (GST_CAT_CAPS, "created %p", static_caps);
512 G_UNLOCK (static_caps_lock);
514 /* ref the caps, makes it not writable */
522 G_UNLOCK (static_caps_lock);
523 g_warning ("static caps %p string is NULL", static_caps);
530 static GstStructure *
531 gst_caps_remove_and_get_structure (GstCaps * caps, guint idx)
533 /* don't use index_fast, gst_caps_do_simplify relies on the order */
534 GstStructure *s = g_ptr_array_remove_index (caps->structs, idx);
536 gst_structure_set_parent_refcount (s, NULL);
541 * gst_caps_steal_structure:
542 * @caps: the #GstCaps to retrieve from
543 * @index: Index of the structure to retrieve
545 * Retrieves the stucture with the given index from the list of structures
546 * contained in @caps. The caller becomes the owner of the returned structure.
548 * Returns: (transfer full): a pointer to the #GstStructure corresponding
554 gst_caps_steal_structure (GstCaps * caps, guint index)
556 g_return_val_if_fail (caps != NULL, NULL);
557 g_return_val_if_fail (IS_WRITABLE (caps), NULL);
559 if (G_UNLIKELY (index >= caps->structs->len))
562 return gst_caps_remove_and_get_structure (caps, index);
566 gst_structure_is_equal_foreach (GQuark field_id, const GValue * val2,
569 GstStructure *struct1 = (GstStructure *) data;
570 const GValue *val1 = gst_structure_id_get_value (struct1, field_id);
572 if (G_UNLIKELY (val1 == NULL))
574 if (gst_value_compare (val1, val2) == GST_VALUE_EQUAL) {
582 gst_caps_structure_is_subset_field (GQuark field_id, const GValue * value,
585 GstStructure *subtract_from = user_data;
586 GValue subtraction = { 0, };
589 if (!(other = gst_structure_id_get_value (subtract_from, field_id)))
590 /* field is missing in one set */
593 /* equal values are subset */
594 if (gst_value_compare (other, value) == GST_VALUE_EQUAL)
602 * -> 1 - [1,2] = empty
606 * -> [1,2] - [1,3] = empty
610 * -> {1,3} - {1,2} = 3
613 * First caps subtraction needs to return a non-empty set, second
614 * subtractions needs to give en empty set.
616 if (gst_value_subtract (&subtraction, other, value)) {
617 g_value_unset (&subtraction);
618 /* !empty result, swapping must be empty */
619 if (!gst_value_subtract (&subtraction, value, other))
622 g_value_unset (&subtraction);
628 gst_caps_structure_is_subset (const GstStructure * minuend,
629 const GstStructure * subtrahend)
631 if ((minuend->name != subtrahend->name) ||
632 (gst_structure_n_fields (minuend) !=
633 gst_structure_n_fields (subtrahend))) {
637 return gst_structure_foreach ((GstStructure *) subtrahend,
638 gst_caps_structure_is_subset_field, (gpointer) minuend);
643 * @caps1: the #GstCaps that will be appended to
644 * @caps2: (transfer full): the #GstCaps to append
646 * Appends the structures contained in @caps2 to @caps1. The structures in
647 * @caps2 are not copied -- they are transferred to @caps1, and then @caps2 is
648 * freed. If either caps is ANY, the resulting caps will be ANY.
651 gst_caps_append (GstCaps * caps1, GstCaps * caps2)
653 GstStructure *structure;
656 g_return_if_fail (GST_IS_CAPS (caps1));
657 g_return_if_fail (GST_IS_CAPS (caps2));
658 g_return_if_fail (IS_WRITABLE (caps1));
659 g_return_if_fail (IS_WRITABLE (caps2));
664 if (G_UNLIKELY (CAPS_IS_ANY (caps1) || CAPS_IS_ANY (caps2))) {
665 /* FIXME: this leaks */
666 caps1->flags |= GST_CAPS_FLAGS_ANY;
667 for (i = caps2->structs->len - 1; i >= 0; i--) {
668 structure = gst_caps_remove_and_get_structure (caps2, i);
669 gst_structure_free (structure);
672 for (i = caps2->structs->len; i; i--) {
673 structure = gst_caps_remove_and_get_structure (caps2, 0);
674 gst_caps_append_structure_unchecked (caps1, structure);
677 gst_caps_unref (caps2); /* guaranteed to free it */
682 * @caps1: the #GstCaps that will take the new entries
683 * @caps2: (transfer full): the #GstCaps to merge in
685 * Appends the structures contained in @caps2 to @caps1 if they are not yet
686 * expressed by @caps1. The structures in @caps2 are not copied -- they are
687 * transferred to @caps1, and then @caps2 is freed.
688 * If either caps is ANY, the resulting caps will be ANY.
693 gst_caps_merge (GstCaps * caps1, GstCaps * caps2)
695 GstStructure *structure;
698 g_return_if_fail (GST_IS_CAPS (caps1));
699 g_return_if_fail (GST_IS_CAPS (caps2));
700 g_return_if_fail (IS_WRITABLE (caps1));
701 g_return_if_fail (IS_WRITABLE (caps2));
706 if (G_UNLIKELY (CAPS_IS_ANY (caps1))) {
707 for (i = caps2->structs->len - 1; i >= 0; i--) {
708 structure = gst_caps_remove_and_get_structure (caps2, i);
709 gst_structure_free (structure);
711 } else if (G_UNLIKELY (CAPS_IS_ANY (caps2))) {
712 caps1->flags |= GST_CAPS_FLAGS_ANY;
713 for (i = caps1->structs->len - 1; i >= 0; i--) {
714 structure = gst_caps_remove_and_get_structure (caps1, i);
715 gst_structure_free (structure);
718 for (i = caps2->structs->len; i; i--) {
719 structure = gst_caps_remove_and_get_structure (caps2, 0);
720 gst_caps_merge_structure (caps1, structure);
723 GstCaps *com = gst_caps_intersect (caps1, caps2);
724 GstCaps *add = gst_caps_subtract (caps2, com);
726 GST_DEBUG ("common : %d", gst_caps_get_size (com));
727 GST_DEBUG ("adding : %d", gst_caps_get_size (add));
728 gst_caps_append (caps1, add);
729 gst_caps_unref (com);
732 gst_caps_unref (caps2); /* guaranteed to free it */
736 * gst_caps_append_structure:
737 * @caps: the #GstCaps that will be appended to
738 * @structure: (transfer full): the #GstStructure to append
740 * Appends @structure to @caps. The structure is not copied; @caps
741 * becomes the owner of @structure.
744 gst_caps_append_structure (GstCaps * caps, GstStructure * structure)
746 g_return_if_fail (GST_IS_CAPS (caps));
747 g_return_if_fail (IS_WRITABLE (caps));
749 if (G_LIKELY (structure)) {
750 g_return_if_fail (structure->parent_refcount == NULL);
753 STRUCTURE_POISON (structure);
756 gst_caps_append_structure_unchecked (caps, structure);
761 * gst_caps_remove_structure:
762 * @caps: the #GstCaps to remove from
763 * @idx: Index of the structure to remove
765 * removes the stucture with the given index from the list of structures
766 * contained in @caps.
769 gst_caps_remove_structure (GstCaps * caps, guint idx)
771 GstStructure *structure;
773 g_return_if_fail (caps != NULL);
774 g_return_if_fail (idx <= gst_caps_get_size (caps));
775 g_return_if_fail (IS_WRITABLE (caps));
777 structure = gst_caps_remove_and_get_structure (caps, idx);
778 gst_structure_free (structure);
782 * gst_caps_merge_structure:
783 * @caps: the #GstCaps that will the the new structure
784 * @structure: (transfer full): the #GstStructure to merge
786 * Appends @structure to @caps if its not already expressed by @caps. The
787 * structure is not copied; @caps becomes the owner of @structure.
790 gst_caps_merge_structure (GstCaps * caps, GstStructure * structure)
792 g_return_if_fail (GST_IS_CAPS (caps));
793 g_return_if_fail (IS_WRITABLE (caps));
795 if (G_LIKELY (structure)) {
796 GstStructure *structure1;
798 gboolean unique = TRUE;
800 g_return_if_fail (structure->parent_refcount == NULL);
803 STRUCTURE_POISON (structure);
806 /* check each structure */
807 for (i = caps->structs->len - 1; i >= 0; i--) {
808 structure1 = gst_caps_get_structure_unchecked (caps, i);
809 /* if structure is a subset of structure1, then skip it */
810 if (gst_caps_structure_is_subset (structure1, structure)) {
816 gst_caps_append_structure_unchecked (caps, structure);
818 gst_structure_free (structure);
827 * Gets the number of structures contained in @caps.
829 * Returns: the number of structures that @caps contains
832 gst_caps_get_size (const GstCaps * caps)
834 g_return_val_if_fail (GST_IS_CAPS (caps), 0);
836 return caps->structs->len;
840 * gst_caps_get_structure:
842 * @index: the index of the structure
844 * Finds the structure in @caps that has the index @index, and
847 * WARNING: This function takes a const GstCaps *, but returns a
848 * non-const GstStructure *. This is for programming convenience --
849 * the caller should be aware that structures inside a constant
850 * #GstCaps should not be modified. However, if you know the caps
851 * are writable, either because you have just copied them or made
852 * them writable with gst_caps_make_writable(), you may modify the
853 * structure returned in the usual way, e.g. with functions like
854 * gst_structure_set().
856 * You do not need to free or unref the structure returned, it
857 * belongs to the #GstCaps.
859 * Returns: (transfer none): a pointer to the #GstStructure corresponding
863 gst_caps_get_structure (const GstCaps * caps, guint index)
865 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
866 g_return_val_if_fail (index < caps->structs->len, NULL);
868 return gst_caps_get_structure_unchecked (caps, index);
873 * @caps: the #GstCaps to copy
874 * @nth: the nth structure to copy
876 * Creates a new #GstCaps and appends a copy of the nth structure
877 * contained in @caps.
879 * Returns: (transfer full): the new #GstCaps
882 gst_caps_copy_nth (const GstCaps * caps, guint nth)
885 GstStructure *structure;
887 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
889 newcaps = gst_caps_new_empty ();
890 newcaps->flags = caps->flags;
892 if (G_LIKELY (caps->structs->len > nth)) {
893 structure = gst_caps_get_structure_unchecked (caps, nth);
894 gst_caps_append_structure_unchecked (newcaps,
895 gst_structure_copy (structure));
903 * @caps: the #GstCaps to truncate
905 * Destructively discard all but the first structure from @caps. Useful when
906 * fixating. @caps must be writable.
909 gst_caps_truncate (GstCaps * caps)
913 g_return_if_fail (GST_IS_CAPS (caps));
914 g_return_if_fail (IS_WRITABLE (caps));
916 i = caps->structs->len - 1;
919 gst_caps_remove_structure (caps, i--);
923 * gst_caps_set_value:
924 * @caps: a writable caps
925 * @field: name of the field to set
926 * @value: value to set the field to
928 * Sets the given @field on all structures of @caps to the given @value.
929 * This is a convenience function for calling gst_structure_set_value() on
930 * all structures of @caps.
935 gst_caps_set_value (GstCaps * caps, const char *field, const GValue * value)
939 g_return_if_fail (GST_IS_CAPS (caps));
940 g_return_if_fail (IS_WRITABLE (caps));
941 g_return_if_fail (field != NULL);
942 g_return_if_fail (G_IS_VALUE (value));
944 len = caps->structs->len;
945 for (i = 0; i < len; i++) {
946 GstStructure *structure = gst_caps_get_structure_unchecked (caps, i);
947 gst_structure_set_value (structure, field, value);
952 * gst_caps_set_simple_valist:
953 * @caps: the #GstCaps to set
954 * @field: first field to set
955 * @varargs: additional parameters
957 * Sets fields in a #GstCaps. The arguments must be passed in the same
958 * manner as gst_structure_set(), and be NULL-terminated.
959 * <note>Prior to GStreamer version 0.10.26, this function failed when
960 * @caps was not simple. If your code needs to work with those versions
961 * of GStreamer, you may only call this function when GST_CAPS_IS_SIMPLE()
962 * is %TRUE for @caps.</note>
965 gst_caps_set_simple_valist (GstCaps * caps, const char *field, va_list varargs)
967 GValue value = { 0, };
969 g_return_if_fail (GST_IS_CAPS (caps));
970 g_return_if_fail (IS_WRITABLE (caps));
976 type = va_arg (varargs, GType);
978 if (G_UNLIKELY (type == G_TYPE_DATE)) {
979 g_warning ("Don't use G_TYPE_DATE, use GST_TYPE_DATE instead\n");
980 type = GST_TYPE_DATE;
982 #if GLIB_CHECK_VERSION(2,23,3)
983 G_VALUE_COLLECT_INIT (&value, type, varargs, 0, &err);
985 g_value_init (&value, type);
986 G_VALUE_COLLECT (&value, varargs, 0, &err);
988 if (G_UNLIKELY (err)) {
989 g_critical ("%s", err);
993 gst_caps_set_value (caps, field, &value);
995 g_value_unset (&value);
997 field = va_arg (varargs, const gchar *);
1002 * gst_caps_set_simple:
1003 * @caps: the #GstCaps to set
1004 * @field: first field to set
1005 * @...: additional parameters
1007 * Sets fields in a #GstCaps. The arguments must be passed in the same
1008 * manner as gst_structure_set(), and be NULL-terminated.
1009 * <note>Prior to GStreamer version 0.10.26, this function failed when
1010 * @caps was not simple. If your code needs to work with those versions
1011 * of GStreamer, you may only call this function when GST_CAPS_IS_SIMPLE()
1012 * is %TRUE for @caps.</note>
1015 gst_caps_set_simple (GstCaps * caps, const char *field, ...)
1019 g_return_if_fail (GST_IS_CAPS (caps));
1020 g_return_if_fail (IS_WRITABLE (caps));
1022 va_start (var_args, field);
1023 gst_caps_set_simple_valist (caps, field, var_args);
1031 * @caps: the #GstCaps to test
1033 * Determines if @caps represents any media format.
1035 * Returns: TRUE if @caps represents any format.
1038 gst_caps_is_any (const GstCaps * caps)
1040 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
1042 return (CAPS_IS_ANY (caps));
1046 * gst_caps_is_empty:
1047 * @caps: the #GstCaps to test
1049 * Determines if @caps represents no media formats.
1051 * Returns: TRUE if @caps represents no formats.
1054 gst_caps_is_empty (const GstCaps * caps)
1056 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
1058 if (CAPS_IS_ANY (caps))
1061 return CAPS_IS_EMPTY_SIMPLE (caps);
1065 gst_caps_is_fixed_foreach (GQuark field_id, const GValue * value,
1068 return gst_value_is_fixed (value);
1072 * gst_caps_is_fixed:
1073 * @caps: the #GstCaps to test
1075 * Fixed #GstCaps describe exactly one format, that is, they have exactly
1076 * one structure, and each field in the structure describes a fixed type.
1077 * Examples of non-fixed types are GST_TYPE_INT_RANGE and GST_TYPE_LIST.
1079 * Returns: TRUE if @caps is fixed
1082 gst_caps_is_fixed (const GstCaps * caps)
1084 GstStructure *structure;
1086 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
1088 if (caps->structs->len != 1)
1091 structure = gst_caps_get_structure_unchecked (caps, 0);
1093 return gst_structure_foreach (structure, gst_caps_is_fixed_foreach, NULL);
1097 * gst_caps_is_equal_fixed:
1098 * @caps1: the #GstCaps to test
1099 * @caps2: the #GstCaps to test
1101 * Tests if two #GstCaps are equal. This function only works on fixed
1104 * Returns: TRUE if the arguments represent the same format
1107 gst_caps_is_equal_fixed (const GstCaps * caps1, const GstCaps * caps2)
1109 GstStructure *struct1, *struct2;
1111 g_return_val_if_fail (gst_caps_is_fixed (caps1), FALSE);
1112 g_return_val_if_fail (gst_caps_is_fixed (caps2), FALSE);
1114 struct1 = gst_caps_get_structure_unchecked (caps1, 0);
1115 struct2 = gst_caps_get_structure_unchecked (caps2, 0);
1117 if (struct1->name != struct2->name) {
1120 if (struct1->fields->len != struct2->fields->len) {
1124 return gst_structure_foreach (struct1, gst_structure_is_equal_foreach,
1129 * gst_caps_is_always_compatible:
1130 * @caps1: the #GstCaps to test
1131 * @caps2: the #GstCaps to test
1133 * A given #GstCaps structure is always compatible with another if
1134 * every media format that is in the first is also contained in the
1135 * second. That is, @caps1 is a subset of @caps2.
1137 * Returns: TRUE if @caps1 is a subset of @caps2.
1140 gst_caps_is_always_compatible (const GstCaps * caps1, const GstCaps * caps2)
1142 g_return_val_if_fail (GST_IS_CAPS (caps1), FALSE);
1143 g_return_val_if_fail (GST_IS_CAPS (caps2), FALSE);
1145 return gst_caps_is_subset (caps1, caps2);
1149 * gst_caps_is_subset:
1150 * @subset: a #GstCaps
1151 * @superset: a potentially greater #GstCaps
1153 * Checks if all caps represented by @subset are also represented by @superset.
1154 * <note>This function does not work reliably if optional properties for caps
1155 * are included on one caps and omitted on the other.</note>
1157 * Returns: %TRUE if @subset is a subset of @superset
1160 gst_caps_is_subset (const GstCaps * subset, const GstCaps * superset)
1165 g_return_val_if_fail (subset != NULL, FALSE);
1166 g_return_val_if_fail (superset != NULL, FALSE);
1168 if (CAPS_IS_EMPTY (subset) || CAPS_IS_ANY (superset))
1170 if (CAPS_IS_ANY (subset) || CAPS_IS_EMPTY (superset))
1173 caps = gst_caps_subtract (subset, superset);
1174 ret = CAPS_IS_EMPTY_SIMPLE (caps);
1175 gst_caps_unref (caps);
1180 * gst_caps_is_equal:
1181 * @caps1: a #GstCaps
1182 * @caps2: another #GstCaps
1184 * Checks if the given caps represent the same set of caps.
1185 * <note>This function does not work reliably if optional properties for caps
1186 * are included on one caps and omitted on the other.</note>
1188 * This function deals correctly with passing NULL for any of the caps.
1190 * Returns: TRUE if both caps are equal.
1193 gst_caps_is_equal (const GstCaps * caps1, const GstCaps * caps2)
1195 /* FIXME 0.11: NULL pointers are no valid Caps but indicate an error
1196 * So there should be an assertion that caps1 and caps2 != NULL */
1198 /* NULL <-> NULL is allowed here */
1199 if (G_UNLIKELY (caps1 == caps2))
1202 /* one of them NULL => they are different (can't be both NULL because
1203 * we checked that above) */
1204 if (G_UNLIKELY (caps1 == NULL || caps2 == NULL))
1207 if (G_UNLIKELY (gst_caps_is_fixed (caps1) && gst_caps_is_fixed (caps2)))
1208 return gst_caps_is_equal_fixed (caps1, caps2);
1210 return gst_caps_is_subset (caps1, caps2) && gst_caps_is_subset (caps2, caps1);
1213 /* intersect operation */
1218 const GstStructure *intersect;
1223 gst_caps_structure_intersect_field1 (GQuark id, const GValue * val1,
1226 IntersectData *idata = (IntersectData *) data;
1227 const GValue *val2 = gst_structure_id_get_value (idata->intersect, id);
1229 if (G_UNLIKELY (val2 == NULL)) {
1230 gst_structure_id_set_value (idata->dest, id, val1);
1232 GValue dest_value = { 0 };
1233 if (gst_value_intersect (&dest_value, val1, val2)) {
1234 gst_structure_id_set_value (idata->dest, id, &dest_value);
1235 g_value_unset (&dest_value);
1244 gst_caps_structure_intersect_field2 (GQuark id, const GValue * val1,
1247 IntersectData *idata = (IntersectData *) data;
1248 const GValue *val2 = gst_structure_id_get_value (idata->intersect, id);
1250 if (G_UNLIKELY (val2 == NULL)) {
1251 gst_structure_id_set_value (idata->dest, id, val1);
1256 static GstStructure *
1257 gst_caps_structure_intersect (const GstStructure * struct1,
1258 const GstStructure * struct2)
1262 g_assert (struct1 != NULL);
1263 g_assert (struct2 != NULL);
1265 if (G_UNLIKELY (struct1->name != struct2->name))
1268 /* copy fields from struct1 which we have not in struct2 to target
1269 * intersect if we have the field in both */
1270 data.dest = gst_structure_id_empty_new (struct1->name);
1271 data.intersect = struct2;
1272 if (G_UNLIKELY (!gst_structure_foreach ((GstStructure *) struct1,
1273 gst_caps_structure_intersect_field1, &data)))
1276 /* copy fields from struct2 which we have not in struct1 to target */
1277 data.intersect = struct1;
1278 if (G_UNLIKELY (!gst_structure_foreach ((GstStructure *) struct2,
1279 gst_caps_structure_intersect_field2, &data)))
1285 gst_structure_free (data.dest);
1290 gst_caps_structure_can_intersect_field (GQuark id, const GValue * val1,
1293 GstStructure *other = (GstStructure *) data;
1294 const GValue *val2 = gst_structure_id_get_value (other, id);
1296 if (G_LIKELY (val2)) {
1297 if (!gst_value_can_intersect (val1, val2)) {
1300 gint eq = gst_value_compare (val1, val2);
1302 if (eq == GST_VALUE_UNORDERED) {
1303 /* we need to try interseting */
1304 GValue dest_value = { 0 };
1305 if (gst_value_intersect (&dest_value, val1, val2)) {
1306 g_value_unset (&dest_value);
1310 } else if (eq != GST_VALUE_EQUAL) {
1319 gst_caps_structure_can_intersect (const GstStructure * struct1,
1320 const GstStructure * struct2)
1322 g_assert (struct1 != NULL);
1323 g_assert (struct2 != NULL);
1325 if (G_UNLIKELY (struct1->name != struct2->name))
1328 /* tries to intersect if we have the field in both */
1329 if (G_UNLIKELY (!gst_structure_foreach ((GstStructure *) struct1,
1330 gst_caps_structure_can_intersect_field, (gpointer) struct2)))
1337 * gst_caps_can_intersect:
1338 * @caps1: a #GstCaps to intersect
1339 * @caps2: a #GstCaps to intersect
1341 * Tries intersecting @caps1 and @caps2 and reports whether the result would not
1344 * Returns: %TRUE if intersection would be not empty
1349 gst_caps_can_intersect (const GstCaps * caps1, const GstCaps * caps2)
1351 guint64 i; /* index can be up to 2 * G_MAX_UINT */
1352 guint j, k, len1, len2;
1353 GstStructure *struct1;
1354 GstStructure *struct2;
1356 g_return_val_if_fail (GST_IS_CAPS (caps1), FALSE);
1357 g_return_val_if_fail (GST_IS_CAPS (caps2), FALSE);
1359 /* caps are exactly the same pointers */
1360 if (G_UNLIKELY (caps1 == caps2))
1363 /* empty caps on either side, return empty */
1364 if (G_UNLIKELY (CAPS_IS_EMPTY (caps1) || CAPS_IS_EMPTY (caps2)))
1367 /* one of the caps is any */
1368 if (G_UNLIKELY (CAPS_IS_ANY (caps1) || CAPS_IS_ANY (caps2)))
1371 /* run zigzag on top line then right line, this preserves the caps order
1372 * much better than a simple loop.
1374 * This algorithm zigzags over the caps structures as demonstrated in
1375 * the folowing matrix:
1378 * +------------- total distance: +-------------
1379 * | 1 2 4 7 0 | 0 1 2 3
1380 * caps2 | 3 5 8 10 1 | 1 2 3 4
1381 * | 6 9 11 12 2 | 2 3 4 5
1383 * First we iterate over the caps1 structures (top line) intersecting
1384 * the structures diagonally down, then we iterate over the caps2
1385 * structures. The result is that the intersections are ordered based on the
1386 * sum of the indexes in the list.
1388 len1 = caps1->structs->len;
1389 len2 = caps2->structs->len;
1390 for (i = 0; i < len1 + len2 - 1; i++) {
1391 /* superset index goes from 0 to sgst_caps_structure_intersectuperset->structs->len-1 */
1392 j = MIN (i, len1 - 1);
1393 /* subset index stays 0 until i reaches superset->structs->len, then it
1394 * counts up from 1 to subset->structs->len - 1 */
1397 /* now run the diagonal line, end condition is the left or bottom
1400 struct1 = gst_caps_get_structure_unchecked (caps1, j);
1401 struct2 = gst_caps_get_structure_unchecked (caps2, k);
1403 if (gst_caps_structure_can_intersect (struct1, struct2)) {
1406 /* move down left */
1408 if (G_UNLIKELY (j == 0))
1409 break; /* so we don't roll back to G_MAXUINT */
1417 * gst_caps_intersect:
1418 * @caps1: a #GstCaps to intersect
1419 * @caps2: a #GstCaps to intersect
1421 * Creates a new #GstCaps that contains all the formats that are common
1422 * to both @caps1 and @caps2.
1424 * Returns: the new #GstCaps
1427 gst_caps_intersect (const GstCaps * caps1, const GstCaps * caps2)
1429 guint64 i; /* index can be up to 2 * G_MAX_UINT */
1430 guint j, k, len1, len2;
1432 GstStructure *struct1;
1433 GstStructure *struct2;
1435 GstStructure *istruct;
1437 g_return_val_if_fail (GST_IS_CAPS (caps1), NULL);
1438 g_return_val_if_fail (GST_IS_CAPS (caps2), NULL);
1440 /* caps are exactly the same pointers, just copy one caps */
1441 if (G_UNLIKELY (caps1 == caps2))
1442 return gst_caps_copy (caps1);
1444 /* empty caps on either side, return empty */
1445 if (G_UNLIKELY (CAPS_IS_EMPTY (caps1) || CAPS_IS_EMPTY (caps2)))
1446 return gst_caps_new_empty ();
1448 /* one of the caps is any, just copy the other caps */
1449 if (G_UNLIKELY (CAPS_IS_ANY (caps1)))
1450 return gst_caps_copy (caps2);
1451 if (G_UNLIKELY (CAPS_IS_ANY (caps2)))
1452 return gst_caps_copy (caps1);
1454 dest = gst_caps_new_empty ();
1456 /* run zigzag on top line then right line, this preserves the caps order
1457 * much better than a simple loop.
1459 * This algorithm zigzags over the caps structures as demonstrated in
1460 * the folowing matrix:
1468 * First we iterate over the caps1 structures (top line) intersecting
1469 * the structures diagonally down, then we iterate over the caps2
1472 len1 = caps1->structs->len;
1473 len2 = caps2->structs->len;
1474 for (i = 0; i < len1 + len2 - 1; i++) {
1475 /* caps1 index goes from 0 to caps1->structs->len-1 */
1476 j = MIN (i, len1 - 1);
1477 /* caps2 index stays 0 until i reaches caps1->structs->len, then it counts
1478 * up from 1 to caps2->structs->len - 1 */
1481 /* now run the diagonal line, end condition is the left or bottom
1484 struct1 = gst_caps_get_structure_unchecked (caps1, j);
1485 struct2 = gst_caps_get_structure_unchecked (caps2, k);
1487 istruct = gst_caps_structure_intersect (struct1, struct2);
1489 gst_caps_append_structure (dest, istruct);
1490 /* move down left */
1492 if (G_UNLIKELY (j == 0))
1493 break; /* so we don't roll back to G_MAXUINT */
1500 /* subtract operation */
1504 const GstStructure *subtract_from;
1510 gst_caps_structure_subtract_field (GQuark field_id, const GValue * value,
1513 SubtractionEntry *e = user_data;
1514 GValue subtraction = { 0, };
1515 const GValue *other;
1516 GstStructure *structure;
1518 other = gst_structure_id_get_value (e->subtract_from, field_id);
1522 if (!gst_value_subtract (&subtraction, other, value))
1524 if (gst_value_compare (&subtraction, other) == GST_VALUE_EQUAL) {
1525 g_value_unset (&subtraction);
1528 structure = gst_structure_copy (e->subtract_from);
1529 gst_structure_id_set_value (structure, field_id, &subtraction);
1530 g_value_unset (&subtraction);
1531 e->put_into = g_slist_prepend (e->put_into, structure);
1537 gst_caps_structure_subtract (GSList ** into, const GstStructure * minuend,
1538 const GstStructure * subtrahend)
1543 e.subtract_from = minuend;
1546 ret = gst_structure_foreach ((GstStructure *) subtrahend,
1547 gst_caps_structure_subtract_field, &e);
1553 for (walk = e.put_into; walk; walk = g_slist_next (walk)) {
1554 gst_structure_free (walk->data);
1556 g_slist_free (e.put_into);
1562 * gst_caps_subtract:
1563 * @minuend: #GstCaps to substract from
1564 * @subtrahend: #GstCaps to substract
1566 * Subtracts the @subtrahend from the @minuend.
1567 * <note>This function does not work reliably if optional properties for caps
1568 * are included on one caps and omitted on the other.</note>
1570 * Returns: the resulting caps
1573 gst_caps_subtract (const GstCaps * minuend, const GstCaps * subtrahend)
1578 GstCaps *dest = NULL, *src;
1580 g_return_val_if_fail (minuend != NULL, NULL);
1581 g_return_val_if_fail (subtrahend != NULL, NULL);
1583 if (CAPS_IS_EMPTY (minuend) || CAPS_IS_ANY (subtrahend)) {
1584 return gst_caps_new_empty ();
1586 if (CAPS_IS_EMPTY_SIMPLE (subtrahend))
1587 return gst_caps_copy (minuend);
1589 /* FIXME: Do we want this here or above?
1590 The reason we need this is that there is no definition about what
1591 ANY means for specific types, so it's not possible to reduce ANY partially
1592 You can only remove everything or nothing and that is done above.
1593 Note: there's a test that checks this behaviour. */
1594 g_return_val_if_fail (!CAPS_IS_ANY (minuend), NULL);
1595 sublen = subtrahend->structs->len;
1598 src = gst_caps_copy (minuend);
1599 for (i = 0; i < sublen; i++) {
1602 sub = gst_caps_get_structure_unchecked (subtrahend, i);
1604 gst_caps_unref (src);
1607 dest = gst_caps_new_empty ();
1608 srclen = src->structs->len;
1609 for (j = 0; j < srclen; j++) {
1610 min = gst_caps_get_structure_unchecked (src, j);
1611 if (gst_structure_get_name_id (min) == gst_structure_get_name_id (sub)) {
1614 if (gst_caps_structure_subtract (&list, min, sub)) {
1617 for (walk = list; walk; walk = g_slist_next (walk)) {
1618 gst_caps_append_structure_unchecked (dest,
1619 (GstStructure *) walk->data);
1621 g_slist_free (list);
1623 gst_caps_append_structure_unchecked (dest, gst_structure_copy (min));
1626 gst_caps_append_structure_unchecked (dest, gst_structure_copy (min));
1629 if (CAPS_IS_EMPTY_SIMPLE (dest)) {
1630 gst_caps_unref (src);
1635 gst_caps_unref (src);
1636 gst_caps_do_simplify (dest);
1640 /* union operation */
1643 static GstStructure *
1644 gst_caps_structure_union (const GstStructure * struct1,
1645 const GstStructure * struct2)
1649 const GstStructureField *field1;
1650 const GstStructureField *field2;
1653 /* FIXME this doesn't actually work */
1655 if (struct1->name != struct2->name)
1658 dest = gst_structure_id_empty_new (struct1->name);
1660 for (i = 0; i < struct1->fields->len; i++) {
1661 GValue dest_value = { 0 };
1663 field1 = GST_STRUCTURE_FIELD (struct1, i);
1664 field2 = gst_structure_id_get_field (struct2, field1->name);
1666 if (field2 == NULL) {
1669 if (gst_value_union (&dest_value, &field1->value, &field2->value)) {
1670 gst_structure_set_value (dest, g_quark_to_string (field1->name),
1673 ret = gst_value_compare (&field1->value, &field2->value);
1684 * @caps1: a #GstCaps to union
1685 * @caps2: a #GstCaps to union
1687 * Creates a new #GstCaps that contains all the formats that are in
1688 * either @caps1 and @caps2.
1690 * Returns: the new #GstCaps
1693 gst_caps_union (const GstCaps * caps1, const GstCaps * caps2)
1698 /* NULL pointers are no correct GstCaps */
1699 g_return_val_if_fail (caps1 != NULL, NULL);
1700 g_return_val_if_fail (caps2 != NULL, NULL);
1702 if (CAPS_IS_EMPTY (caps1))
1703 return gst_caps_copy (caps2);
1705 if (CAPS_IS_EMPTY (caps2))
1706 return gst_caps_copy (caps1);
1708 if (CAPS_IS_ANY (caps1) || CAPS_IS_ANY (caps2))
1709 return gst_caps_new_any ();
1711 dest1 = gst_caps_copy (caps1);
1712 dest2 = gst_caps_copy (caps2);
1713 gst_caps_append (dest1, dest2);
1715 gst_caps_do_simplify (dest1);
1719 /* normalize/simplify operations */
1721 typedef struct _NormalizeForeach
1724 GstStructure *structure;
1729 gst_caps_normalize_foreach (GQuark field_id, const GValue * value, gpointer ptr)
1731 NormalizeForeach *nf = (NormalizeForeach *) ptr;
1735 if (G_VALUE_TYPE (value) == GST_TYPE_LIST) {
1736 guint len = gst_value_list_get_size (value);
1737 for (i = 1; i < len; i++) {
1738 const GValue *v = gst_value_list_get_value (value, i);
1739 GstStructure *structure = gst_structure_copy (nf->structure);
1741 gst_structure_id_set_value (structure, field_id, v);
1742 gst_caps_append_structure_unchecked (nf->caps, structure);
1745 gst_value_init_and_copy (&val, gst_value_list_get_value (value, 0));
1746 gst_structure_id_set_value (nf->structure, field_id, &val);
1747 g_value_unset (&val);
1755 * gst_caps_normalize:
1756 * @caps: a #GstCaps to normalize
1758 * Creates a new #GstCaps that represents the same set of formats as
1759 * @caps, but contains no lists. Each list is expanded into separate
1762 * Returns: the new #GstCaps
1765 gst_caps_normalize (const GstCaps * caps)
1767 NormalizeForeach nf;
1771 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
1773 newcaps = gst_caps_copy (caps);
1776 for (i = 0; i < gst_caps_get_size (newcaps); i++) {
1777 nf.structure = gst_caps_get_structure_unchecked (newcaps, i);
1779 while (!gst_structure_foreach (nf.structure,
1780 gst_caps_normalize_foreach, &nf));
1787 gst_caps_compare_structures (gconstpointer one, gconstpointer two)
1790 const GstStructure *struct1 = *((const GstStructure **) one);
1791 const GstStructure *struct2 = *((const GstStructure **) two);
1793 /* FIXME: this orders alphabetically, but ordering the quarks might be faster
1794 So what's the best way? */
1795 ret = strcmp (gst_structure_get_name (struct1),
1796 gst_structure_get_name (struct2));
1800 return gst_structure_n_fields (struct2) - gst_structure_n_fields (struct1);
1807 GstStructure *compare;
1812 gst_caps_structure_figure_out_union (GQuark field_id, const GValue * value,
1815 UnionField *u = user_data;
1816 const GValue *val = gst_structure_id_get_value (u->compare, field_id);
1820 g_value_unset (&u->value);
1823 if (gst_value_compare (val, value) == GST_VALUE_EQUAL)
1826 g_value_unset (&u->value);
1830 gst_value_union (&u->value, val, value);
1835 gst_caps_structure_simplify (GstStructure ** result,
1836 const GstStructure * simplify, GstStructure * compare)
1839 UnionField field = { 0, {0,}, NULL };
1841 /* try to subtract to get a real subset */
1842 if (gst_caps_structure_subtract (&list, simplify, compare)) {
1843 if (list == NULL) { /* no result */
1846 } else if (list->next == NULL) { /* one result */
1847 *result = list->data;
1848 g_slist_free (list);
1850 } else { /* multiple results */
1851 g_slist_foreach (list, (GFunc) gst_structure_free, NULL);
1852 g_slist_free (list);
1857 /* try to union both structs */
1858 field.compare = compare;
1859 if (gst_structure_foreach ((GstStructure *) simplify,
1860 gst_caps_structure_figure_out_union, &field)) {
1861 gboolean ret = FALSE;
1863 /* now we know all of simplify's fields are the same in compare
1864 * but at most one field: field.name */
1865 if (G_IS_VALUE (&field.value)) {
1866 if (gst_structure_n_fields (simplify) == gst_structure_n_fields (compare)) {
1867 gst_structure_id_set_value (compare, field.name, &field.value);
1871 g_value_unset (&field.value);
1872 } else if (gst_structure_n_fields (simplify) <=
1873 gst_structure_n_fields (compare)) {
1874 /* compare is just more specific, will be optimized away later */
1875 /* FIXME: do this here? */
1876 GST_LOG ("found a case that will be optimized later.");
1878 gchar *one = gst_structure_to_string (simplify);
1879 gchar *two = gst_structure_to_string (compare);
1882 ("caps mismatch: structures %s and %s claim to be possible to unify, but aren't",
1894 gst_caps_switch_structures (GstCaps * caps, GstStructure * old,
1895 GstStructure * new, gint i)
1897 gst_structure_set_parent_refcount (old, NULL);
1898 gst_structure_free (old);
1899 gst_structure_set_parent_refcount (new, &caps->refcount);
1900 g_ptr_array_index (caps->structs, i) = new;
1904 * gst_caps_do_simplify:
1905 * @caps: a #GstCaps to simplify
1907 * Modifies the given @caps inplace into a representation that represents the
1908 * same set of formats, but in a simpler form. Component structures that are
1909 * identical are merged. Component structures that have values that can be
1910 * merged are also merged.
1912 * Returns: TRUE, if the caps could be simplified
1915 gst_caps_do_simplify (GstCaps * caps)
1917 GstStructure *simplify, *compare, *result = NULL;
1919 gboolean changed = FALSE;
1921 g_return_val_if_fail (caps != NULL, FALSE);
1922 g_return_val_if_fail (IS_WRITABLE (caps), FALSE);
1924 if (gst_caps_get_size (caps) < 2)
1927 g_ptr_array_sort (caps->structs, gst_caps_compare_structures);
1929 start = caps->structs->len - 1;
1930 for (i = caps->structs->len - 1; i >= 0; i--) {
1931 simplify = gst_caps_get_structure_unchecked (caps, i);
1932 if (gst_structure_get_name_id (simplify) !=
1933 gst_structure_get_name_id (gst_caps_get_structure_unchecked (caps,
1936 for (j = start; j >= 0; j--) {
1939 compare = gst_caps_get_structure_unchecked (caps, j);
1940 if (gst_structure_get_name_id (simplify) !=
1941 gst_structure_get_name_id (compare)) {
1944 if (gst_caps_structure_simplify (&result, simplify, compare)) {
1946 gst_caps_switch_structures (caps, simplify, result, i);
1949 gst_caps_remove_structure (caps, i);
1961 /* gst_caps_do_simplify (caps); */
1967 #if !defined(GST_DISABLE_LOADSAVE) && !defined(GST_REMOVE_DEPRECATED)
1969 * gst_caps_save_thyself:
1970 * @caps: a #GstCaps structure
1971 * @parent: a XML parent node
1973 * Serializes a #GstCaps to XML and adds it as a child node of @parent.
1975 * Returns: a XML node pointer
1978 gst_caps_save_thyself (const GstCaps * caps, xmlNodePtr parent)
1980 char *s = gst_caps_to_string (caps);
1982 xmlNewChild (parent, NULL, (xmlChar *) "caps", (xmlChar *) s);
1988 * gst_caps_load_thyself:
1989 * @parent: a XML node
1991 * Creates a #GstCaps from its XML serialization.
1993 * Returns: a new #GstCaps structure
1996 gst_caps_load_thyself (xmlNodePtr parent)
1998 if (strcmp ("caps", (char *) parent->name) == 0) {
1999 return gst_caps_from_string ((gchar *) xmlNodeGetContent (parent));
2010 * @caps: (inout) (transfer full): a pointer to #GstCaps
2011 * @newcaps: a #GstCaps to replace *caps
2013 * Replaces *caps with @newcaps. Unrefs the #GstCaps in the location
2014 * pointed to by @caps, if applicable, then modifies @caps to point to
2015 * @newcaps. An additional ref on @newcaps is taken.
2017 * This function does not take any locks so you might want to lock
2018 * the object owning @caps pointer.
2021 gst_caps_replace (GstCaps ** caps, GstCaps * newcaps)
2025 g_return_if_fail (caps != NULL);
2029 GST_CAT_TRACE (GST_CAT_REFCOUNTING, "%p, %p -> %p", caps, oldcaps, newcaps);
2031 if (newcaps != oldcaps) {
2033 gst_caps_ref (newcaps);
2038 gst_caps_unref (oldcaps);
2043 * gst_caps_to_string:
2046 * Converts @caps to a string representation. This string representation
2047 * can be converted back to a #GstCaps by gst_caps_from_string().
2049 * For debugging purposes its easier to do something like this:
2051 * GST_LOG ("caps are %" GST_PTR_FORMAT, caps);
2053 * This prints the caps in human readble form.
2055 * Returns: (transfer full): a newly allocated string representing @caps.
2058 gst_caps_to_string (const GstCaps * caps)
2060 guint i, slen, clen;
2063 /* NOTE: This function is potentially called by the debug system,
2064 * so any calls to gst_log() (and GST_DEBUG(), GST_LOG(), etc.)
2065 * should be careful to avoid recursion. This includes any functions
2066 * called by gst_caps_to_string. In particular, calls should
2067 * not use the GST_PTR_FORMAT extension. */
2070 return g_strdup ("NULL");
2072 if (CAPS_IS_ANY (caps)) {
2073 return g_strdup ("ANY");
2075 if (CAPS_IS_EMPTY_SIMPLE (caps)) {
2076 return g_strdup ("EMPTY");
2079 /* estimate a rough string length to avoid unnecessary reallocs in GString */
2081 clen = caps->structs->len;
2082 for (i = 0; i < clen; i++) {
2084 STRUCTURE_ESTIMATED_STRING_LEN (gst_caps_get_structure_unchecked (caps,
2088 s = g_string_sized_new (slen);
2089 for (i = 0; i < clen; i++) {
2090 GstStructure *structure;
2093 /* ';' is now added by gst_structure_to_string */
2094 g_string_append_c (s, ' ');
2097 structure = gst_caps_get_structure_unchecked (caps, i);
2098 priv_gst_structure_append_to_gstring (structure, s);
2100 if (s->len && s->str[s->len - 1] == ';') {
2101 /* remove latest ';' */
2102 s->str[--s->len] = '\0';
2104 return g_string_free (s, FALSE);
2108 gst_caps_from_string_inplace (GstCaps * caps, const gchar * string)
2110 GstStructure *structure;
2113 if (strcmp ("ANY", string) == 0) {
2114 caps->flags = GST_CAPS_FLAGS_ANY;
2117 if (strcmp ("EMPTY", string) == 0) {
2121 structure = gst_structure_from_string (string, &s);
2122 if (structure == NULL) {
2125 gst_caps_append_structure_unchecked (caps, structure);
2129 while (g_ascii_isspace (*s))
2134 structure = gst_structure_from_string (s, &s);
2135 if (structure == NULL) {
2138 gst_caps_append_structure_unchecked (caps, structure);
2146 * gst_caps_from_string:
2147 * @string: a string to convert to #GstCaps
2149 * Converts @caps from a string representation.
2151 * Returns: (transfer full): a newly allocated #GstCaps
2154 gst_caps_from_string (const gchar * string)
2158 g_return_val_if_fail (string, FALSE);
2160 caps = gst_caps_new_empty ();
2161 if (gst_caps_from_string_inplace (caps, string)) {
2164 gst_caps_unref (caps);
2170 gst_caps_transform_to_string (const GValue * src_value, GValue * dest_value)
2172 g_return_if_fail (G_IS_VALUE (src_value));
2173 g_return_if_fail (G_IS_VALUE (dest_value));
2174 g_return_if_fail (G_VALUE_HOLDS (src_value, GST_TYPE_CAPS));
2175 g_return_if_fail (G_VALUE_HOLDS (dest_value, G_TYPE_STRING)
2176 || G_VALUE_HOLDS (dest_value, G_TYPE_POINTER));
2178 dest_value->data[0].v_pointer =
2179 gst_caps_to_string (src_value->data[0].v_pointer);
2183 gst_caps_copy_conditional (GstCaps * src)
2186 return gst_caps_ref (src);