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",
47 * "format", G_TYPE_STRING, "I420",
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 #define DEBUG_REFCOUNT
78 typedef struct _GstCapsImpl
85 #define GST_CAPS_ARRAY(c) (((GstCapsImpl *)(c))->array)
87 #define GST_CAPS_LEN(c) (GST_CAPS_ARRAY(c)->len)
89 #define IS_WRITABLE(caps) \
90 (GST_CAPS_REFCOUNT_VALUE (caps) == 1)
92 /* same as gst_caps_is_any () */
93 #define CAPS_IS_ANY(caps) \
94 (GST_CAPS_FLAGS(caps) & GST_CAPS_FLAG_ANY)
96 /* same as gst_caps_is_empty () */
97 #define CAPS_IS_EMPTY(caps) \
98 (!CAPS_IS_ANY(caps) && CAPS_IS_EMPTY_SIMPLE(caps))
100 #define CAPS_IS_EMPTY_SIMPLE(caps) \
101 ((GST_CAPS_ARRAY (caps) == NULL) || (GST_CAPS_LEN (caps) == 0))
103 /* quick way to get a caps structure at an index without doing a type or array
105 #define gst_caps_get_structure_unchecked(caps, index) \
106 ((GstStructure *)g_ptr_array_index (GST_CAPS_ARRAY (caps), (index)))
107 /* quick way to append a structure without checking the args */
108 #define gst_caps_append_structure_unchecked(caps, structure) G_STMT_START{\
109 GstStructure *__s=structure; \
110 if (gst_structure_set_parent_refcount (__s, &GST_MINI_OBJECT_REFCOUNT(caps))) \
111 g_ptr_array_add (GST_CAPS_ARRAY (caps), __s); \
114 /* lock to protect multiple invocations of static caps to caps conversion */
115 G_LOCK_DEFINE_STATIC (static_caps_lock);
117 static void gst_caps_transform_to_string (const GValue * src_value,
118 GValue * dest_value);
119 static gboolean gst_caps_from_string_inplace (GstCaps * caps,
120 const gchar * string);
122 GType _gst_caps_type = 0;
123 GstCaps *_gst_caps_any;
124 GstCaps *_gst_caps_none;
126 GST_DEFINE_MINI_OBJECT_TYPE (GstCaps, gst_caps);
129 _priv_gst_caps_initialize (void)
131 _gst_caps_type = gst_caps_get_type ();
133 _gst_caps_any = gst_caps_new_any ();
134 _gst_caps_none = gst_caps_new_empty ();
136 g_value_register_transform_func (_gst_caps_type,
137 G_TYPE_STRING, gst_caps_transform_to_string);
141 _gst_caps_copy (const GstCaps * caps)
144 GstStructure *structure;
147 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
149 newcaps = gst_caps_new_empty ();
150 GST_CAPS_FLAGS (newcaps) = GST_CAPS_FLAGS (caps);
151 n = GST_CAPS_LEN (caps);
153 for (i = 0; i < n; i++) {
154 structure = gst_caps_get_structure_unchecked (caps, i);
155 gst_caps_append_structure (newcaps, gst_structure_copy (structure));
161 /* creation/deletion */
163 _gst_caps_free (GstCaps * caps)
165 GstStructure *structure;
168 /* The refcount must be 0, but since we're only called by gst_caps_unref,
169 * don't bother testing. */
170 len = GST_CAPS_LEN (caps);
171 /* This can be used to get statistics about caps sizes */
172 /*GST_CAT_INFO (GST_CAT_CAPS, "caps size: %d", len); */
173 for (i = 0; i < len; i++) {
174 structure = (GstStructure *) gst_caps_get_structure_unchecked (caps, i);
175 gst_structure_set_parent_refcount (structure, NULL);
176 gst_structure_free (structure);
178 g_ptr_array_free (GST_CAPS_ARRAY (caps), TRUE);
180 #ifdef DEBUG_REFCOUNT
181 GST_CAT_LOG (GST_CAT_CAPS, "freeing caps %p", caps);
183 g_slice_free1 (GST_MINI_OBJECT_SIZE (caps), caps);
187 gst_caps_init (GstCaps * caps, gsize size)
189 gst_mini_object_init (GST_MINI_OBJECT_CAST (caps), _gst_caps_type, size);
191 caps->mini_object.copy = (GstMiniObjectCopyFunction) _gst_caps_copy;
192 caps->mini_object.dispose = NULL;
193 caps->mini_object.free = (GstMiniObjectFreeFunction) _gst_caps_free;
195 /* the 32 has been determined by logging caps sizes in _gst_caps_free
196 * but g_ptr_array uses 16 anyway if it expands once, so this does not help
198 * GST_CAPS_ARRAY (caps) = g_ptr_array_sized_new (32);
200 GST_CAPS_ARRAY (caps) = g_ptr_array_new ();
204 * gst_caps_new_empty:
206 * Creates a new #GstCaps that is empty. That is, the returned
207 * #GstCaps contains no media formats.
208 * Caller is responsible for unreffing the returned caps.
210 * Returns: (transfer full): the new #GstCaps
213 gst_caps_new_empty (void)
217 caps = (GstCaps *) g_slice_new (GstCapsImpl);
219 gst_caps_init (caps, sizeof (GstCapsImpl));
221 #ifdef DEBUG_REFCOUNT
222 GST_CAT_TRACE (GST_CAT_CAPS, "created caps %p", caps);
231 * Creates a new #GstCaps that indicates that it is compatible with
234 * Returns: (transfer full): the new #GstCaps
237 gst_caps_new_any (void)
239 GstCaps *caps = gst_caps_new_empty ();
241 GST_CAPS_FLAG_SET (caps, GST_CAPS_FLAG_ANY);
247 * gst_caps_new_empty_simple:
248 * @media_type: the media type of the structure
250 * Creates a new #GstCaps that contains one #GstStructure with name
252 * Caller is responsible for unreffing the returned caps.
254 * Returns: (transfer full): the new #GstCaps
257 gst_caps_new_empty_simple (const char *media_type)
260 GstStructure *structure;
262 caps = gst_caps_new_empty ();
263 structure = gst_structure_new_empty (media_type);
265 gst_caps_append_structure_unchecked (caps, structure);
271 * gst_caps_new_simple:
272 * @media_type: the media type of the structure
273 * @fieldname: first field to set
274 * @...: additional arguments
276 * Creates a new #GstCaps that contains one #GstStructure. The
277 * structure is defined by the arguments, which have the same format
278 * as gst_structure_new().
279 * Caller is responsible for unreffing the returned caps.
281 * Returns: (transfer full): the new #GstCaps
284 gst_caps_new_simple (const char *media_type, const char *fieldname, ...)
287 GstStructure *structure;
290 caps = gst_caps_new_empty ();
292 va_start (var_args, fieldname);
293 structure = gst_structure_new_valist (media_type, fieldname, var_args);
297 gst_caps_append_structure_unchecked (caps, structure);
299 gst_caps_replace (&caps, NULL);
306 * @struct1: the first structure to add
307 * @...: additional structures to add
309 * Creates a new #GstCaps and adds all the structures listed as
310 * arguments. The list must be NULL-terminated. The structures
311 * are not copied; the returned #GstCaps owns the structures.
313 * Returns: (transfer full): the new #GstCaps
316 gst_caps_new_full (GstStructure * struct1, ...)
321 va_start (var_args, struct1);
322 caps = gst_caps_new_full_valist (struct1, var_args);
329 * gst_caps_new_full_valist:
330 * @structure: the first structure to add
331 * @var_args: additional structures to add
333 * Creates a new #GstCaps and adds all the structures listed as
334 * arguments. The list must be NULL-terminated. The structures
335 * are not copied; the returned #GstCaps owns the structures.
337 * Returns: (transfer full): the new #GstCaps
340 gst_caps_new_full_valist (GstStructure * structure, va_list var_args)
344 caps = gst_caps_new_empty ();
347 gst_caps_append_structure_unchecked (caps, structure);
348 structure = va_arg (var_args, GstStructure *);
354 G_DEFINE_POINTER_TYPE (GstStaticCaps, gst_static_caps);
357 * gst_static_caps_get:
358 * @static_caps: the #GstStaticCaps to convert
360 * Converts a #GstStaticCaps to a #GstCaps.
362 * Returns: (transfer full): a pointer to the #GstCaps. Unref after usage.
363 * Since the core holds an additional ref to the returned caps,
364 * use gst_caps_make_writable() on the returned caps to modify it.
367 gst_static_caps_get (GstStaticCaps * static_caps)
371 g_return_val_if_fail (static_caps != NULL, NULL);
373 caps = &static_caps->caps;
375 /* refcount is 0 when we need to convert */
376 if (G_UNLIKELY (*caps == NULL)) {
379 G_LOCK (static_caps_lock);
380 /* check if other thread already updated */
381 if (G_UNLIKELY (*caps != NULL))
384 string = static_caps->string;
386 if (G_UNLIKELY (string == NULL))
389 *caps = gst_caps_from_string (string);
391 /* convert to string */
392 if (G_UNLIKELY (*caps == NULL))
393 g_critical ("Could not convert static caps \"%s\"", string);
395 GST_CAT_TRACE (GST_CAT_CAPS, "created %p from string %s", static_caps,
398 G_UNLOCK (static_caps_lock);
400 /* ref the caps, makes it not writable */
401 if (G_LIKELY (*caps != NULL))
402 gst_caps_ref (*caps);
409 G_UNLOCK (static_caps_lock);
410 g_warning ("static caps %p string is NULL", static_caps);
416 * gst_static_caps_cleanup:
417 * @static_caps: the #GstStaticCaps to clean
419 * Clean up the cached caps contained in @static_caps.
422 gst_static_caps_cleanup (GstStaticCaps * static_caps)
424 G_LOCK (static_caps_lock);
425 gst_caps_replace (&static_caps->caps, NULL);
426 G_UNLOCK (static_caps_lock);
431 static GstStructure *
432 gst_caps_remove_and_get_structure (GstCaps * caps, guint idx)
434 /* don't use index_fast, gst_caps_do_simplify relies on the order */
435 GstStructure *s = g_ptr_array_remove_index (GST_CAPS_ARRAY (caps), idx);
437 gst_structure_set_parent_refcount (s, NULL);
442 * gst_caps_steal_structure:
443 * @caps: the #GstCaps to retrieve from
444 * @index: Index of the structure to retrieve
446 * Retrieves the stucture with the given index from the list of structures
447 * contained in @caps. The caller becomes the owner of the returned structure.
449 * Returns: (transfer full): a pointer to the #GstStructure corresponding
455 gst_caps_steal_structure (GstCaps * caps, guint index)
457 g_return_val_if_fail (caps != NULL, NULL);
458 g_return_val_if_fail (IS_WRITABLE (caps), NULL);
460 if (G_UNLIKELY (index >= GST_CAPS_LEN (caps)))
463 return gst_caps_remove_and_get_structure (caps, index);
468 * @caps1: the #GstCaps that will be appended to
469 * @caps2: (transfer full): the #GstCaps to append
471 * Appends the structures contained in @caps2 to @caps1. The structures in
472 * @caps2 are not copied -- they are transferred to @caps1, and then @caps2 is
473 * freed. If either caps is ANY, the resulting caps will be ANY.
476 gst_caps_append (GstCaps * caps1, GstCaps * caps2)
478 GstStructure *structure;
481 g_return_if_fail (GST_IS_CAPS (caps1));
482 g_return_if_fail (GST_IS_CAPS (caps2));
483 g_return_if_fail (IS_WRITABLE (caps1));
485 caps2 = gst_caps_make_writable (caps2);
487 if (G_UNLIKELY (CAPS_IS_ANY (caps1) || CAPS_IS_ANY (caps2))) {
488 /* FIXME: this leaks */
489 GST_CAPS_FLAGS (caps1) |= GST_CAPS_FLAG_ANY;
490 for (i = GST_CAPS_LEN (caps2) - 1; i >= 0; i--) {
491 structure = gst_caps_remove_and_get_structure (caps2, i);
492 gst_structure_free (structure);
495 for (i = GST_CAPS_LEN (caps2); i; i--) {
496 structure = gst_caps_remove_and_get_structure (caps2, 0);
497 gst_caps_append_structure_unchecked (caps1, structure);
500 gst_caps_unref (caps2); /* guaranteed to free it */
505 * @caps1: the #GstCaps that will take the new entries
506 * @caps2: (transfer full): the #GstCaps to merge in
508 * Appends the structures contained in @caps2 to @caps1 if they are not yet
509 * expressed by @caps1. The structures in @caps2 are not copied -- they are
510 * transferred to @caps1, and then @caps2 is freed.
511 * If either caps is ANY, the resulting caps will be ANY.
516 gst_caps_merge (GstCaps * caps1, GstCaps * caps2)
518 GstStructure *structure;
521 g_return_if_fail (GST_IS_CAPS (caps1));
522 g_return_if_fail (GST_IS_CAPS (caps2));
523 g_return_if_fail (IS_WRITABLE (caps1));
525 caps2 = gst_caps_make_writable (caps2);
527 if (G_UNLIKELY (CAPS_IS_ANY (caps1))) {
528 for (i = GST_CAPS_LEN (caps2) - 1; i >= 0; i--) {
529 structure = gst_caps_remove_and_get_structure (caps2, i);
530 gst_structure_free (structure);
532 } else if (G_UNLIKELY (CAPS_IS_ANY (caps2))) {
533 GST_CAPS_FLAGS (caps1) |= GST_CAPS_FLAG_ANY;
534 for (i = GST_CAPS_LEN (caps1) - 1; i >= 0; i--) {
535 structure = gst_caps_remove_and_get_structure (caps1, i);
536 gst_structure_free (structure);
539 for (i = GST_CAPS_LEN (caps2); i; i--) {
540 structure = gst_caps_remove_and_get_structure (caps2, 0);
541 gst_caps_merge_structure (caps1, structure);
544 GstCaps *com = gst_caps_intersect (caps1, caps2);
545 GstCaps *add = gst_caps_subtract (caps2, com);
547 GST_DEBUG ("common : %d", gst_caps_get_size (com));
548 GST_DEBUG ("adding : %d", gst_caps_get_size (add));
549 gst_caps_append (caps1, add);
550 gst_caps_unref (com);
553 gst_caps_unref (caps2); /* guaranteed to free it */
557 * gst_caps_append_structure:
558 * @caps: the #GstCaps that will be appended to
559 * @structure: (transfer full): the #GstStructure to append
561 * Appends @structure to @caps. The structure is not copied; @caps
562 * becomes the owner of @structure.
565 gst_caps_append_structure (GstCaps * caps, GstStructure * structure)
567 g_return_if_fail (GST_IS_CAPS (caps));
568 g_return_if_fail (IS_WRITABLE (caps));
570 if (G_LIKELY (structure)) {
571 gst_caps_append_structure_unchecked (caps, structure);
576 * gst_caps_remove_structure:
577 * @caps: the #GstCaps to remove from
578 * @idx: Index of the structure to remove
580 * removes the stucture with the given index from the list of structures
581 * contained in @caps.
584 gst_caps_remove_structure (GstCaps * caps, guint idx)
586 GstStructure *structure;
588 g_return_if_fail (caps != NULL);
589 g_return_if_fail (idx <= gst_caps_get_size (caps));
590 g_return_if_fail (IS_WRITABLE (caps));
592 structure = gst_caps_remove_and_get_structure (caps, idx);
593 gst_structure_free (structure);
597 * gst_caps_merge_structure:
598 * @caps: the #GstCaps that will the new structure
599 * @structure: (transfer full): the #GstStructure to merge
601 * Appends @structure to @caps if its not already expressed by @caps. The
602 * structure is not copied; @caps becomes the owner of @structure.
605 gst_caps_merge_structure (GstCaps * caps, GstStructure * structure)
607 g_return_if_fail (GST_IS_CAPS (caps));
608 g_return_if_fail (IS_WRITABLE (caps));
610 if (G_LIKELY (structure)) {
611 GstStructure *structure1;
613 gboolean unique = TRUE;
615 /* check each structure */
616 for (i = GST_CAPS_LEN (caps) - 1; i >= 0; i--) {
617 structure1 = gst_caps_get_structure_unchecked (caps, i);
618 /* if structure is a subset of structure1, then skip it */
619 if (gst_structure_is_subset (structure, structure1)) {
625 gst_caps_append_structure_unchecked (caps, structure);
627 gst_structure_free (structure);
636 * Gets the number of structures contained in @caps.
638 * Returns: the number of structures that @caps contains
641 gst_caps_get_size (const GstCaps * caps)
643 g_return_val_if_fail (GST_IS_CAPS (caps), 0);
645 return GST_CAPS_LEN (caps);
649 * gst_caps_get_structure:
651 * @index: the index of the structure
653 * Finds the structure in @caps that has the index @index, and
656 * WARNING: This function takes a const GstCaps *, but returns a
657 * non-const GstStructure *. This is for programming convenience --
658 * the caller should be aware that structures inside a constant
659 * #GstCaps should not be modified. However, if you know the caps
660 * are writable, either because you have just copied them or made
661 * them writable with gst_caps_make_writable(), you may modify the
662 * structure returned in the usual way, e.g. with functions like
663 * gst_structure_set().
665 * You do not need to free or unref the structure returned, it
666 * belongs to the #GstCaps.
668 * Returns: (transfer none): a pointer to the #GstStructure corresponding
672 gst_caps_get_structure (const GstCaps * caps, guint index)
674 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
675 g_return_val_if_fail (index < GST_CAPS_LEN (caps), NULL);
677 return gst_caps_get_structure_unchecked (caps, index);
682 * @caps: the #GstCaps to copy
683 * @nth: the nth structure to copy
685 * Creates a new #GstCaps and appends a copy of the nth structure
686 * contained in @caps.
688 * Returns: (transfer full): the new #GstCaps
691 gst_caps_copy_nth (const GstCaps * caps, guint nth)
694 GstStructure *structure;
696 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
698 newcaps = gst_caps_new_empty ();
699 GST_CAPS_FLAGS (newcaps) = GST_CAPS_FLAGS (caps);
701 if (G_LIKELY (GST_CAPS_LEN (caps) > nth)) {
702 structure = gst_caps_get_structure_unchecked (caps, nth);
703 gst_caps_append_structure_unchecked (newcaps,
704 gst_structure_copy (structure));
712 * @caps: the #GstCaps to truncate
714 * Destructively discard all but the first structure from @caps. Useful when
715 * fixating. @caps must be writable.
718 gst_caps_truncate (GstCaps * caps)
722 g_return_if_fail (GST_IS_CAPS (caps));
723 g_return_if_fail (IS_WRITABLE (caps));
725 i = GST_CAPS_LEN (caps) - 1;
728 gst_caps_remove_structure (caps, i--);
732 * gst_caps_set_value:
733 * @caps: a writable caps
734 * @field: name of the field to set
735 * @value: value to set the field to
737 * Sets the given @field on all structures of @caps to the given @value.
738 * This is a convenience function for calling gst_structure_set_value() on
739 * all structures of @caps.
744 gst_caps_set_value (GstCaps * caps, const char *field, const GValue * value)
748 g_return_if_fail (GST_IS_CAPS (caps));
749 g_return_if_fail (IS_WRITABLE (caps));
750 g_return_if_fail (field != NULL);
751 g_return_if_fail (G_IS_VALUE (value));
753 len = GST_CAPS_LEN (caps);
754 for (i = 0; i < len; i++) {
755 GstStructure *structure = gst_caps_get_structure_unchecked (caps, i);
756 gst_structure_set_value (structure, field, value);
761 * gst_caps_set_simple_valist:
762 * @caps: the #GstCaps to set
763 * @field: first field to set
764 * @varargs: additional parameters
766 * Sets fields in a #GstCaps. The arguments must be passed in the same
767 * manner as gst_structure_set(), and be NULL-terminated.
768 * <note>Prior to GStreamer version 0.10.26, this function failed when
769 * @caps was not simple. If your code needs to work with those versions
770 * of GStreamer, you may only call this function when GST_CAPS_IS_SIMPLE()
771 * is %TRUE for @caps.</note>
774 gst_caps_set_simple_valist (GstCaps * caps, const char *field, va_list varargs)
776 GValue value = { 0, };
778 g_return_if_fail (GST_IS_CAPS (caps));
779 g_return_if_fail (IS_WRITABLE (caps));
785 type = va_arg (varargs, GType);
787 G_VALUE_COLLECT_INIT (&value, type, varargs, 0, &err);
788 if (G_UNLIKELY (err)) {
789 g_critical ("%s", err);
793 gst_caps_set_value (caps, field, &value);
795 g_value_unset (&value);
797 field = va_arg (varargs, const gchar *);
802 * gst_caps_set_simple:
803 * @caps: the #GstCaps to set
804 * @field: first field to set
805 * @...: additional parameters
807 * Sets fields in a #GstCaps. The arguments must be passed in the same
808 * manner as gst_structure_set(), and be NULL-terminated.
809 * <note>Prior to GStreamer version 0.10.26, this function failed when
810 * @caps was not simple. If your code needs to work with those versions
811 * of GStreamer, you may only call this function when GST_CAPS_IS_SIMPLE()
812 * is %TRUE for @caps.</note>
815 gst_caps_set_simple (GstCaps * caps, const char *field, ...)
819 g_return_if_fail (GST_IS_CAPS (caps));
820 g_return_if_fail (IS_WRITABLE (caps));
822 va_start (var_args, field);
823 gst_caps_set_simple_valist (caps, field, var_args);
831 * @caps: the #GstCaps to test
833 * Determines if @caps represents any media format.
835 * Returns: TRUE if @caps represents any format.
838 gst_caps_is_any (const GstCaps * caps)
840 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
842 return (CAPS_IS_ANY (caps));
847 * @caps: the #GstCaps to test
849 * Determines if @caps represents no media formats.
851 * Returns: TRUE if @caps represents no formats.
854 gst_caps_is_empty (const GstCaps * caps)
856 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
858 if (CAPS_IS_ANY (caps))
861 return CAPS_IS_EMPTY_SIMPLE (caps);
865 gst_caps_is_fixed_foreach (GQuark field_id, const GValue * value,
868 return gst_value_is_fixed (value);
873 * @caps: the #GstCaps to test
875 * Fixed #GstCaps describe exactly one format, that is, they have exactly
876 * one structure, and each field in the structure describes a fixed type.
877 * Examples of non-fixed types are GST_TYPE_INT_RANGE and GST_TYPE_LIST.
879 * Returns: TRUE if @caps is fixed
882 gst_caps_is_fixed (const GstCaps * caps)
884 GstStructure *structure;
886 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
888 if (GST_CAPS_LEN (caps) != 1)
891 structure = gst_caps_get_structure_unchecked (caps, 0);
893 return gst_structure_foreach (structure, gst_caps_is_fixed_foreach, NULL);
897 * gst_caps_is_equal_fixed:
898 * @caps1: the #GstCaps to test
899 * @caps2: the #GstCaps to test
901 * Tests if two #GstCaps are equal. This function only works on fixed
904 * Returns: TRUE if the arguments represent the same format
907 gst_caps_is_equal_fixed (const GstCaps * caps1, const GstCaps * caps2)
909 GstStructure *struct1, *struct2;
911 g_return_val_if_fail (gst_caps_is_fixed (caps1), FALSE);
912 g_return_val_if_fail (gst_caps_is_fixed (caps2), FALSE);
914 struct1 = gst_caps_get_structure_unchecked (caps1, 0);
915 struct2 = gst_caps_get_structure_unchecked (caps2, 0);
917 return gst_structure_is_equal (struct1, struct2);
921 * gst_caps_is_always_compatible:
922 * @caps1: the #GstCaps to test
923 * @caps2: the #GstCaps to test
925 * A given #GstCaps structure is always compatible with another if
926 * every media format that is in the first is also contained in the
927 * second. That is, @caps1 is a subset of @caps2.
929 * Returns: TRUE if @caps1 is a subset of @caps2.
932 gst_caps_is_always_compatible (const GstCaps * caps1, const GstCaps * caps2)
934 g_return_val_if_fail (GST_IS_CAPS (caps1), FALSE);
935 g_return_val_if_fail (GST_IS_CAPS (caps2), FALSE);
937 return gst_caps_is_subset (caps1, caps2);
941 * gst_caps_is_subset:
942 * @subset: a #GstCaps
943 * @superset: a potentially greater #GstCaps
945 * Checks if all caps represented by @subset are also represented by @superset.
946 * <note>This function does not work reliably if optional properties for caps
947 * are included on one caps and omitted on the other.</note>
949 * Returns: %TRUE if @subset is a subset of @superset
952 gst_caps_is_subset (const GstCaps * subset, const GstCaps * superset)
954 GstStructure *s1, *s2;
958 g_return_val_if_fail (subset != NULL, FALSE);
959 g_return_val_if_fail (superset != NULL, FALSE);
961 if (CAPS_IS_EMPTY (subset) || CAPS_IS_ANY (superset))
963 if (CAPS_IS_ANY (subset) || CAPS_IS_EMPTY (superset))
966 for (i = GST_CAPS_LEN (subset) - 1; i >= 0; i--) {
967 for (j = GST_CAPS_LEN (superset) - 1; j >= 0; j--) {
968 s1 = gst_caps_get_structure_unchecked (subset, i);
969 s2 = gst_caps_get_structure_unchecked (superset, j);
970 if (gst_structure_is_subset (s1, s2)) {
971 /* If we found a superset, continue with the next
972 * subset structure */
976 /* If we found no superset for this subset structure
977 * we return FALSE immediately */
988 * gst_caps_is_subset_structure:
990 * @structure: a potential #GstStructure subset of @caps
992 * Checks if @structure is a subset of @caps. See gst_caps_is_subset()
993 * for more information.
995 * Returns: %TRUE if @structure is a subset of @caps
1000 gst_caps_is_subset_structure (const GstCaps * caps,
1001 const GstStructure * structure)
1006 g_return_val_if_fail (caps != NULL, FALSE);
1007 g_return_val_if_fail (structure != NULL, FALSE);
1009 if (CAPS_IS_ANY (caps))
1011 if (CAPS_IS_EMPTY (caps))
1014 for (i = GST_CAPS_LEN (caps) - 1; i >= 0; i--) {
1015 s = gst_caps_get_structure_unchecked (caps, i);
1016 if (gst_structure_is_subset (structure, s)) {
1017 /* If we found a superset return TRUE */
1026 * gst_caps_is_equal:
1027 * @caps1: a #GstCaps
1028 * @caps2: another #GstCaps
1030 * Checks if the given caps represent the same set of caps.
1031 * <note>This function does not work reliably if optional properties for caps
1032 * are included on one caps and omitted on the other.</note>
1034 * This function deals correctly with passing NULL for any of the caps.
1036 * Returns: TRUE if both caps are equal.
1039 gst_caps_is_equal (const GstCaps * caps1, const GstCaps * caps2)
1041 /* FIXME 0.11: NULL pointers are no valid Caps but indicate an error
1042 * So there should be an assertion that caps1 and caps2 != NULL */
1044 /* NULL <-> NULL is allowed here */
1045 if (G_UNLIKELY (caps1 == caps2))
1048 /* one of them NULL => they are different (can't be both NULL because
1049 * we checked that above) */
1050 if (G_UNLIKELY (caps1 == NULL || caps2 == NULL))
1053 if (G_UNLIKELY (gst_caps_is_fixed (caps1) && gst_caps_is_fixed (caps2)))
1054 return gst_caps_is_equal_fixed (caps1, caps2);
1056 return gst_caps_is_subset (caps1, caps2) && gst_caps_is_subset (caps2, caps1);
1060 * gst_caps_is_strictly_equal:
1061 * @caps1: a #GstCaps
1062 * @caps2: another #GstCaps
1064 * Checks if the given caps are exactly the same set of caps.
1066 * This function deals correctly with passing NULL for any of the caps.
1068 * Returns: TRUE if both caps are strictly equal.
1073 gst_caps_is_strictly_equal (const GstCaps * caps1, const GstCaps * caps2)
1076 /* FIXME 0.11: NULL pointers are no valid Caps but indicate an error
1077 * So there should be an assertion that caps1 and caps2 != NULL */
1079 /* NULL <-> NULL is allowed here */
1080 if (G_UNLIKELY (caps1 == caps2))
1083 /* one of them NULL => they are different (can't be both NULL because
1084 * we checked that above) */
1085 if (G_UNLIKELY (caps1 == NULL || caps2 == NULL))
1088 if (GST_CAPS_LEN (caps1) != GST_CAPS_LEN (caps2))
1091 for (i = 0; i < GST_CAPS_LEN (caps1); i++) {
1092 if (!gst_structure_is_equal (gst_caps_get_structure_unchecked (caps1, i),
1093 gst_caps_get_structure_unchecked (caps2, i)))
1100 /* intersect operation */
1103 * gst_caps_can_intersect:
1104 * @caps1: a #GstCaps to intersect
1105 * @caps2: a #GstCaps to intersect
1107 * Tries intersecting @caps1 and @caps2 and reports whether the result would not
1110 * Returns: %TRUE if intersection would be not empty
1115 gst_caps_can_intersect (const GstCaps * caps1, const GstCaps * caps2)
1117 guint64 i; /* index can be up to 2 * G_MAX_UINT */
1118 guint j, k, len1, len2;
1119 GstStructure *struct1;
1120 GstStructure *struct2;
1122 g_return_val_if_fail (GST_IS_CAPS (caps1), FALSE);
1123 g_return_val_if_fail (GST_IS_CAPS (caps2), FALSE);
1125 /* caps are exactly the same pointers */
1126 if (G_UNLIKELY (caps1 == caps2))
1129 /* empty caps on either side, return empty */
1130 if (G_UNLIKELY (CAPS_IS_EMPTY (caps1) || CAPS_IS_EMPTY (caps2)))
1133 /* one of the caps is any */
1134 if (G_UNLIKELY (CAPS_IS_ANY (caps1) || CAPS_IS_ANY (caps2)))
1137 /* run zigzag on top line then right line, this preserves the caps order
1138 * much better than a simple loop.
1140 * This algorithm zigzags over the caps structures as demonstrated in
1141 * the folowing matrix:
1144 * +------------- total distance: +-------------
1145 * | 1 2 4 7 0 | 0 1 2 3
1146 * caps2 | 3 5 8 10 1 | 1 2 3 4
1147 * | 6 9 11 12 2 | 2 3 4 5
1149 * First we iterate over the caps1 structures (top line) intersecting
1150 * the structures diagonally down, then we iterate over the caps2
1151 * structures. The result is that the intersections are ordered based on the
1152 * sum of the indexes in the list.
1154 len1 = GST_CAPS_LEN (caps1);
1155 len2 = GST_CAPS_LEN (caps2);
1156 for (i = 0; i < len1 + len2 - 1; i++) {
1157 /* superset index goes from 0 to sgst_caps_structure_intersectuperset->structs->len-1 */
1158 j = MIN (i, len1 - 1);
1159 /* subset index stays 0 until i reaches superset->structs->len, then it
1160 * counts up from 1 to subset->structs->len - 1 */
1161 k = (i > j) ? (i - j) : 0; /* MAX (0, i - j) */
1163 /* now run the diagonal line, end condition is the left or bottom
1166 struct1 = gst_caps_get_structure_unchecked (caps1, j);
1167 struct2 = gst_caps_get_structure_unchecked (caps2, k);
1169 if (gst_structure_can_intersect (struct1, struct2)) {
1172 /* move down left */
1174 if (G_UNLIKELY (j == 0))
1175 break; /* so we don't roll back to G_MAXUINT */
1183 gst_caps_intersect_zig_zag (const GstCaps * caps1, const GstCaps * caps2)
1185 guint64 i; /* index can be up to 2 * G_MAX_UINT */
1186 guint j, k, len1, len2;
1188 GstStructure *struct1;
1189 GstStructure *struct2;
1191 GstStructure *istruct;
1193 /* caps are exactly the same pointers, just copy one caps */
1194 if (G_UNLIKELY (caps1 == caps2))
1195 return _gst_caps_copy (caps1);
1197 /* empty caps on either side, return empty */
1198 if (G_UNLIKELY (CAPS_IS_EMPTY (caps1) || CAPS_IS_EMPTY (caps2)))
1199 return gst_caps_new_empty ();
1201 /* one of the caps is any, just copy the other caps */
1202 if (G_UNLIKELY (CAPS_IS_ANY (caps1)))
1203 return _gst_caps_copy (caps2);
1204 if (G_UNLIKELY (CAPS_IS_ANY (caps2)))
1205 return _gst_caps_copy (caps1);
1207 dest = gst_caps_new_empty ();
1209 /* run zigzag on top line then right line, this preserves the caps order
1210 * much better than a simple loop.
1212 * This algorithm zigzags over the caps structures as demonstrated in
1213 * the folowing matrix:
1221 * First we iterate over the caps1 structures (top line) intersecting
1222 * the structures diagonally down, then we iterate over the caps2
1225 len1 = GST_CAPS_LEN (caps1);
1226 len2 = GST_CAPS_LEN (caps2);
1227 for (i = 0; i < len1 + len2 - 1; i++) {
1228 /* caps1 index goes from 0 to GST_CAPS_LEN (caps1)-1 */
1229 j = MIN (i, len1 - 1);
1230 /* caps2 index stays 0 until i reaches GST_CAPS_LEN (caps1), then it counts
1231 * up from 1 to GST_CAPS_LEN (caps2) - 1 */
1232 k = (i > j) ? (i - j) : 0; /* MAX (0, i - j) */
1234 /* now run the diagonal line, end condition is the left or bottom
1237 struct1 = gst_caps_get_structure_unchecked (caps1, j);
1238 struct2 = gst_caps_get_structure_unchecked (caps2, k);
1240 istruct = gst_structure_intersect (struct1, struct2);
1242 gst_caps_merge_structure (dest, istruct);
1243 /* move down left */
1245 if (G_UNLIKELY (j == 0))
1246 break; /* so we don't roll back to G_MAXUINT */
1254 * gst_caps_intersect_first:
1255 * @caps1: a #GstCaps to intersect
1256 * @caps2: a #GstCaps to intersect
1258 * Creates a new #GstCaps that contains all the formats that are common
1259 * to both @caps1 and @caps2.
1261 * Unlike @gst_caps_intersect, the returned caps will be ordered in a similar
1262 * fashion as @caps1.
1264 * Returns: the new #GstCaps
1267 gst_caps_intersect_first (const GstCaps * caps1, const GstCaps * caps2)
1270 guint j, len1, len2;
1272 GstStructure *struct1;
1273 GstStructure *struct2;
1275 GstStructure *istruct;
1277 /* caps are exactly the same pointers, just copy one caps */
1278 if (G_UNLIKELY (caps1 == caps2))
1279 return gst_caps_copy (caps1);
1281 /* empty caps on either side, return empty */
1282 if (G_UNLIKELY (CAPS_IS_EMPTY (caps1) || CAPS_IS_EMPTY (caps2)))
1283 return gst_caps_new_empty ();
1285 /* one of the caps is any, just copy the other caps */
1286 if (G_UNLIKELY (CAPS_IS_ANY (caps1)))
1287 return gst_caps_copy (caps2);
1288 if (G_UNLIKELY (CAPS_IS_ANY (caps2)))
1289 return gst_caps_copy (caps1);
1291 dest = gst_caps_new_empty ();
1293 len1 = GST_CAPS_LEN (caps1);
1294 len2 = GST_CAPS_LEN (caps2);
1295 for (i = 0; i < len1; i++) {
1296 struct1 = gst_caps_get_structure_unchecked (caps1, i);
1297 for (j = 0; j < len2; j++) {
1298 struct2 = gst_caps_get_structure_unchecked (caps2, j);
1299 istruct = gst_structure_intersect (struct1, struct2);
1301 gst_caps_merge_structure (dest, istruct);
1309 * gst_caps_intersect_full:
1310 * @caps1: a #GstCaps to intersect
1311 * @caps2: a #GstCaps to intersect
1312 * @mode: The intersection algorithm/mode to use
1314 * Creates a new #GstCaps that contains all the formats that are common
1315 * to both @caps1 and @caps2, the order is defined by the #GstCapsIntersectMode
1318 * Returns: the new #GstCaps
1322 gst_caps_intersect_full (const GstCaps * caps1, const GstCaps * caps2,
1323 GstCapsIntersectMode mode)
1325 g_return_val_if_fail (GST_IS_CAPS (caps1), NULL);
1326 g_return_val_if_fail (GST_IS_CAPS (caps2), NULL);
1329 case GST_CAPS_INTERSECT_FIRST:
1330 return gst_caps_intersect_first (caps1, caps2);
1332 g_warning ("Unknown caps intersect mode: %d", mode);
1334 case GST_CAPS_INTERSECT_ZIG_ZAG:
1335 return gst_caps_intersect_zig_zag (caps1, caps2);
1340 * gst_caps_intersect:
1341 * @caps1: a #GstCaps to intersect
1342 * @caps2: a #GstCaps to intersect
1344 * Creates a new #GstCaps that contains all the formats that are common
1345 * to both @caps1 and @caps2. Defaults to %GST_CAPS_INTERSECT_ZIG_ZAG mode.
1347 * Returns: the new #GstCaps
1350 gst_caps_intersect (const GstCaps * caps1, const GstCaps * caps2)
1352 return gst_caps_intersect_full (caps1, caps2, GST_CAPS_INTERSECT_ZIG_ZAG);
1356 /* subtract operation */
1360 const GstStructure *subtract_from;
1366 gst_caps_structure_subtract_field (GQuark field_id, const GValue * value,
1369 SubtractionEntry *e = user_data;
1370 GValue subtraction = { 0, };
1371 const GValue *other;
1372 GstStructure *structure;
1374 other = gst_structure_id_get_value (e->subtract_from, field_id);
1378 if (!gst_value_subtract (&subtraction, other, value))
1380 if (gst_value_compare (&subtraction, other) == GST_VALUE_EQUAL) {
1381 g_value_unset (&subtraction);
1384 structure = gst_structure_copy (e->subtract_from);
1385 gst_structure_id_set_value (structure, field_id, &subtraction);
1386 g_value_unset (&subtraction);
1387 e->put_into = g_slist_prepend (e->put_into, structure);
1393 gst_caps_structure_subtract (GSList ** into, const GstStructure * minuend,
1394 const GstStructure * subtrahend)
1399 e.subtract_from = minuend;
1402 ret = gst_structure_foreach ((GstStructure *) subtrahend,
1403 gst_caps_structure_subtract_field, &e);
1409 for (walk = e.put_into; walk; walk = g_slist_next (walk)) {
1410 gst_structure_free (walk->data);
1412 g_slist_free (e.put_into);
1418 * gst_caps_subtract:
1419 * @minuend: #GstCaps to subtract from
1420 * @subtrahend: #GstCaps to subtract
1422 * Subtracts the @subtrahend from the @minuend.
1423 * <note>This function does not work reliably if optional properties for caps
1424 * are included on one caps and omitted on the other.</note>
1426 * Returns: the resulting caps
1429 gst_caps_subtract (const GstCaps * minuend, const GstCaps * subtrahend)
1434 GstCaps *dest = NULL, *src;
1436 g_return_val_if_fail (minuend != NULL, NULL);
1437 g_return_val_if_fail (subtrahend != NULL, NULL);
1439 if (CAPS_IS_EMPTY (minuend) || CAPS_IS_ANY (subtrahend)) {
1440 return gst_caps_new_empty ();
1442 if (CAPS_IS_EMPTY_SIMPLE (subtrahend))
1443 return _gst_caps_copy (minuend);
1445 /* FIXME: Do we want this here or above?
1446 The reason we need this is that there is no definition about what
1447 ANY means for specific types, so it's not possible to reduce ANY partially
1448 You can only remove everything or nothing and that is done above.
1449 Note: there's a test that checks this behaviour. */
1450 g_return_val_if_fail (!CAPS_IS_ANY (minuend), NULL);
1451 sublen = GST_CAPS_LEN (subtrahend);
1452 g_assert (sublen > 0);
1454 src = _gst_caps_copy (minuend);
1455 for (i = 0; i < sublen; i++) {
1458 sub = gst_caps_get_structure_unchecked (subtrahend, i);
1460 gst_caps_unref (src);
1463 dest = gst_caps_new_empty ();
1464 srclen = GST_CAPS_LEN (src);
1465 for (j = 0; j < srclen; j++) {
1466 min = gst_caps_get_structure_unchecked (src, j);
1467 if (gst_structure_get_name_id (min) == gst_structure_get_name_id (sub)) {
1470 if (gst_caps_structure_subtract (&list, min, sub)) {
1473 for (walk = list; walk; walk = g_slist_next (walk)) {
1474 gst_caps_append_structure_unchecked (dest,
1475 (GstStructure *) walk->data);
1477 g_slist_free (list);
1479 gst_caps_append_structure_unchecked (dest, gst_structure_copy (min));
1482 gst_caps_append_structure_unchecked (dest, gst_structure_copy (min));
1485 if (CAPS_IS_EMPTY_SIMPLE (dest)) {
1486 gst_caps_unref (src);
1491 gst_caps_unref (src);
1492 gst_caps_do_simplify (dest);
1496 /* union operation */
1499 static GstStructure *
1500 gst_caps_structure_union (const GstStructure * struct1,
1501 const GstStructure * struct2)
1505 const GstStructureField *field1;
1506 const GstStructureField *field2;
1509 /* FIXME this doesn't actually work */
1511 if (struct1->name != struct2->name)
1514 dest = gst_structure_new_id_empty (struct1->name);
1516 for (i = 0; i < struct1->fields->len; i++) {
1517 GValue dest_value = { 0 };
1519 field1 = GST_STRUCTURE_FIELD (struct1, i);
1520 field2 = gst_structure_id_get_field (struct2, field1->name);
1522 if (field2 == NULL) {
1525 if (gst_value_union (&dest_value, &field1->value, &field2->value)) {
1526 gst_structure_set_value (dest, g_quark_to_string (field1->name),
1529 ret = gst_value_compare (&field1->value, &field2->value);
1540 * @caps1: a #GstCaps to union
1541 * @caps2: a #GstCaps to union
1543 * Creates a new #GstCaps that contains all the formats that are in
1544 * either @caps1 and @caps2.
1546 * Returns: the new #GstCaps
1549 gst_caps_union (const GstCaps * caps1, const GstCaps * caps2)
1554 /* NULL pointers are no correct GstCaps */
1555 g_return_val_if_fail (caps1 != NULL, NULL);
1556 g_return_val_if_fail (caps2 != NULL, NULL);
1558 if (CAPS_IS_EMPTY (caps1))
1559 return _gst_caps_copy (caps2);
1561 if (CAPS_IS_EMPTY (caps2))
1562 return _gst_caps_copy (caps1);
1564 if (CAPS_IS_ANY (caps1) || CAPS_IS_ANY (caps2))
1565 return gst_caps_new_any ();
1567 dest1 = _gst_caps_copy (caps1);
1568 dest2 = _gst_caps_copy (caps2);
1569 gst_caps_append (dest1, dest2);
1571 gst_caps_do_simplify (dest1);
1575 /* normalize/simplify operations */
1577 typedef struct _NormalizeForeach
1580 GstStructure *structure;
1585 gst_caps_normalize_foreach (GQuark field_id, const GValue * value, gpointer ptr)
1587 NormalizeForeach *nf = (NormalizeForeach *) ptr;
1591 if (G_VALUE_TYPE (value) == GST_TYPE_LIST) {
1592 guint len = gst_value_list_get_size (value);
1593 for (i = 1; i < len; i++) {
1594 const GValue *v = gst_value_list_get_value (value, i);
1595 GstStructure *structure = gst_structure_copy (nf->structure);
1597 gst_structure_id_set_value (structure, field_id, v);
1598 gst_caps_append_structure_unchecked (nf->caps, structure);
1601 gst_value_init_and_copy (&val, gst_value_list_get_value (value, 0));
1602 gst_structure_id_set_value (nf->structure, field_id, &val);
1603 g_value_unset (&val);
1611 * gst_caps_normalize:
1612 * @caps: a #GstCaps to normalize
1614 * Creates a new #GstCaps that represents the same set of formats as
1615 * @caps, but contains no lists. Each list is expanded into separate
1618 * Returns: the new #GstCaps
1621 gst_caps_normalize (const GstCaps * caps)
1623 NormalizeForeach nf;
1627 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
1629 newcaps = _gst_caps_copy (caps);
1632 for (i = 0; i < gst_caps_get_size (newcaps); i++) {
1633 nf.structure = gst_caps_get_structure_unchecked (newcaps, i);
1635 while (!gst_structure_foreach (nf.structure,
1636 gst_caps_normalize_foreach, &nf));
1643 gst_caps_compare_structures (gconstpointer one, gconstpointer two)
1646 const GstStructure *struct1 = *((const GstStructure **) one);
1647 const GstStructure *struct2 = *((const GstStructure **) two);
1649 /* FIXME: this orders alphabetically, but ordering the quarks might be faster
1650 So what's the best way? */
1651 ret = strcmp (gst_structure_get_name (struct1),
1652 gst_structure_get_name (struct2));
1656 return gst_structure_n_fields (struct2) - gst_structure_n_fields (struct1);
1663 GstStructure *compare;
1668 gst_caps_structure_figure_out_union (GQuark field_id, const GValue * value,
1671 UnionField *u = user_data;
1672 const GValue *val = gst_structure_id_get_value (u->compare, field_id);
1676 g_value_unset (&u->value);
1679 if (gst_value_compare (val, value) == GST_VALUE_EQUAL)
1682 g_value_unset (&u->value);
1686 gst_value_union (&u->value, val, value);
1691 gst_caps_structure_simplify (GstStructure ** result,
1692 const GstStructure * simplify, GstStructure * compare)
1695 UnionField field = { 0, {0,}, NULL };
1697 /* try to subtract to get a real subset */
1698 if (gst_caps_structure_subtract (&list, simplify, compare)) {
1699 if (list == NULL) { /* no result */
1702 } else if (list->next == NULL) { /* one result */
1703 *result = list->data;
1704 g_slist_free (list);
1706 } else { /* multiple results */
1707 g_slist_foreach (list, (GFunc) gst_structure_free, NULL);
1708 g_slist_free (list);
1713 /* try to union both structs */
1714 field.compare = compare;
1715 if (gst_structure_foreach ((GstStructure *) simplify,
1716 gst_caps_structure_figure_out_union, &field)) {
1717 gboolean ret = FALSE;
1719 /* now we know all of simplify's fields are the same in compare
1720 * but at most one field: field.name */
1721 if (G_IS_VALUE (&field.value)) {
1722 if (gst_structure_n_fields (simplify) == gst_structure_n_fields (compare)) {
1723 gst_structure_id_set_value (compare, field.name, &field.value);
1727 g_value_unset (&field.value);
1728 } else if (gst_structure_n_fields (simplify) <=
1729 gst_structure_n_fields (compare)) {
1730 /* compare is just more specific, will be optimized away later */
1731 /* FIXME: do this here? */
1732 GST_LOG ("found a case that will be optimized later.");
1734 gchar *one = gst_structure_to_string (simplify);
1735 gchar *two = gst_structure_to_string (compare);
1738 ("caps mismatch: structures %s and %s claim to be possible to unify, but aren't",
1750 gst_caps_switch_structures (GstCaps * caps, GstStructure * old,
1751 GstStructure * new, gint i)
1753 gst_structure_set_parent_refcount (old, NULL);
1754 gst_structure_free (old);
1755 gst_structure_set_parent_refcount (new, &GST_CAPS_REFCOUNT (caps));
1756 g_ptr_array_index (GST_CAPS_ARRAY (caps), i) = new;
1760 * gst_caps_do_simplify:
1761 * @caps: a #GstCaps to simplify
1763 * Modifies the given @caps inplace into a representation that represents the
1764 * same set of formats, but in a simpler form. Component structures that are
1765 * identical are merged. Component structures that have values that can be
1766 * merged are also merged.
1768 * Returns: TRUE, if the caps could be simplified
1771 gst_caps_do_simplify (GstCaps * caps)
1773 GstStructure *simplify, *compare, *result = NULL;
1775 gboolean changed = FALSE;
1777 g_return_val_if_fail (caps != NULL, FALSE);
1778 g_return_val_if_fail (IS_WRITABLE (caps), FALSE);
1780 if (gst_caps_get_size (caps) < 2)
1783 g_ptr_array_sort (GST_CAPS_ARRAY (caps), gst_caps_compare_structures);
1785 start = GST_CAPS_LEN (caps) - 1;
1786 for (i = GST_CAPS_LEN (caps) - 1; i >= 0; i--) {
1787 simplify = gst_caps_get_structure_unchecked (caps, i);
1788 if (gst_structure_get_name_id (simplify) !=
1789 gst_structure_get_name_id (gst_caps_get_structure_unchecked (caps,
1792 for (j = start; j >= 0; j--) {
1795 compare = gst_caps_get_structure_unchecked (caps, j);
1796 if (gst_structure_get_name_id (simplify) !=
1797 gst_structure_get_name_id (compare)) {
1800 if (gst_caps_structure_simplify (&result, simplify, compare)) {
1802 gst_caps_switch_structures (caps, simplify, result, i);
1805 gst_caps_remove_structure (caps, i);
1817 /* gst_caps_do_simplify (caps); */
1823 * @caps: a #GstCaps to fixate
1825 * Modifies the given @caps inplace into a representation with only fixed
1826 * values. First the caps will be truncated and then the first structure will be
1827 * fixated with gst_structure_fixate(). @caps should be writable.
1830 gst_caps_fixate (GstCaps * caps)
1834 g_return_if_fail (GST_IS_CAPS (caps));
1835 g_return_if_fail (IS_WRITABLE (caps));
1837 /* default fixation */
1838 gst_caps_truncate (caps);
1839 s = gst_caps_get_structure (caps, 0);
1840 gst_structure_fixate (s);
1846 * gst_caps_to_string:
1849 * Converts @caps to a string representation. This string representation
1850 * can be converted back to a #GstCaps by gst_caps_from_string().
1852 * For debugging purposes its easier to do something like this:
1854 * GST_LOG ("caps are %" GST_PTR_FORMAT, caps);
1856 * This prints the caps in human readble form.
1858 * Returns: (transfer full): a newly allocated string representing @caps.
1861 gst_caps_to_string (const GstCaps * caps)
1863 guint i, slen, clen;
1866 /* NOTE: This function is potentially called by the debug system,
1867 * so any calls to gst_log() (and GST_DEBUG(), GST_LOG(), etc.)
1868 * should be careful to avoid recursion. This includes any functions
1869 * called by gst_caps_to_string. In particular, calls should
1870 * not use the GST_PTR_FORMAT extension. */
1873 return g_strdup ("NULL");
1875 if (CAPS_IS_ANY (caps)) {
1876 return g_strdup ("ANY");
1878 if (CAPS_IS_EMPTY_SIMPLE (caps)) {
1879 return g_strdup ("EMPTY");
1882 /* estimate a rough string length to avoid unnecessary reallocs in GString */
1884 clen = GST_CAPS_LEN (caps);
1885 for (i = 0; i < clen; i++) {
1887 STRUCTURE_ESTIMATED_STRING_LEN (gst_caps_get_structure_unchecked (caps,
1891 s = g_string_sized_new (slen);
1892 for (i = 0; i < clen; i++) {
1893 GstStructure *structure;
1896 /* ';' is now added by gst_structure_to_string */
1897 g_string_append_c (s, ' ');
1900 structure = gst_caps_get_structure_unchecked (caps, i);
1901 priv_gst_structure_append_to_gstring (structure, s);
1903 if (s->len && s->str[s->len - 1] == ';') {
1904 /* remove latest ';' */
1905 s->str[--s->len] = '\0';
1907 return g_string_free (s, FALSE);
1911 gst_caps_from_string_inplace (GstCaps * caps, const gchar * string)
1913 GstStructure *structure;
1916 if (strcmp ("ANY", string) == 0) {
1917 GST_CAPS_FLAGS (caps) = GST_CAPS_FLAG_ANY;
1920 if (strcmp ("EMPTY", string) == 0) {
1924 structure = gst_structure_from_string (string, &s);
1925 if (structure == NULL) {
1928 gst_caps_append_structure_unchecked (caps, structure);
1932 while (g_ascii_isspace (*s))
1937 structure = gst_structure_from_string (s, &s);
1938 if (structure == NULL) {
1941 gst_caps_append_structure_unchecked (caps, structure);
1949 * gst_caps_from_string:
1950 * @string: a string to convert to #GstCaps
1952 * Converts @caps from a string representation.
1954 * Returns: (transfer full): a newly allocated #GstCaps
1957 gst_caps_from_string (const gchar * string)
1961 g_return_val_if_fail (string, FALSE);
1963 caps = gst_caps_new_empty ();
1964 if (gst_caps_from_string_inplace (caps, string)) {
1967 gst_caps_unref (caps);
1973 gst_caps_transform_to_string (const GValue * src_value, GValue * dest_value)
1975 g_return_if_fail (G_IS_VALUE (src_value));
1976 g_return_if_fail (G_IS_VALUE (dest_value));
1977 g_return_if_fail (G_VALUE_HOLDS (src_value, GST_TYPE_CAPS));
1978 g_return_if_fail (G_VALUE_HOLDS (dest_value, G_TYPE_STRING)
1979 || G_VALUE_HOLDS (dest_value, G_TYPE_POINTER));
1981 g_value_take_string (dest_value,
1982 gst_caps_to_string (gst_value_get_caps (src_value)));