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 #define DEBUG_REFCOUNT
78 #define IS_WRITABLE(caps) \
79 (GST_CAPS_REFCOUNT_VALUE (caps) == 1)
81 /* same as gst_caps_is_any () */
82 #define CAPS_IS_ANY(caps) \
83 (GST_CAPS_FLAGS(caps) & GST_CAPS_FLAGS_ANY)
85 /* same as gst_caps_is_empty () */
86 #define CAPS_IS_EMPTY(caps) \
87 (!CAPS_IS_ANY(caps) && CAPS_IS_EMPTY_SIMPLE(caps))
89 #define CAPS_IS_EMPTY_SIMPLE(caps) \
90 (((caps)->structs == NULL) || ((caps)->structs->len == 0))
92 /* quick way to get a caps structure at an index without doing a type or array
94 #define gst_caps_get_structure_unchecked(caps, index) \
95 ((GstStructure *)g_ptr_array_index ((caps)->structs, (index)))
96 /* quick way to append a structure without checking the args */
97 #define gst_caps_append_structure_unchecked(caps, structure) G_STMT_START{\
98 GstStructure *__s=structure; \
99 if (gst_structure_set_parent_refcount (__s, &GST_MINI_OBJECT_REFCOUNT(caps))) \
100 g_ptr_array_add (caps->structs, __s); \
103 /* lock to protect multiple invocations of static caps to caps conversion */
104 G_LOCK_DEFINE_STATIC (static_caps_lock);
106 static void gst_caps_transform_to_string (const GValue * src_value,
107 GValue * dest_value);
108 static gboolean gst_caps_from_string_inplace (GstCaps * caps,
109 const gchar * string);
111 GType _gst_caps_type = 0;
114 _gst_caps_initialize (void)
116 _gst_caps_type = gst_mini_object_register ("GstCaps");
118 g_value_register_transform_func (_gst_caps_type,
119 G_TYPE_STRING, gst_caps_transform_to_string);
123 _gst_caps_copy (const GstCaps * caps)
126 GstStructure *structure;
129 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
131 newcaps = gst_caps_new_empty ();
132 GST_CAPS_FLAGS (newcaps) = GST_CAPS_FLAGS (caps);
133 n = caps->structs->len;
135 for (i = 0; i < n; i++) {
136 structure = gst_caps_get_structure_unchecked (caps, i);
137 gst_caps_append_structure (newcaps, gst_structure_copy (structure));
143 /* creation/deletion */
145 _gst_caps_free (GstCaps * caps)
147 GstStructure *structure;
150 /* The refcount must be 0, but since we're only called by gst_caps_unref,
151 * don't bother testing. */
152 len = caps->structs->len;
153 /* This can be used to get statistics about caps sizes */
154 /*GST_CAT_INFO (GST_CAT_CAPS, "caps size: %d", len); */
155 for (i = 0; i < len; i++) {
156 structure = (GstStructure *) gst_caps_get_structure_unchecked (caps, i);
157 gst_structure_set_parent_refcount (structure, NULL);
158 gst_structure_free (structure);
160 g_ptr_array_free (caps->structs, TRUE);
162 #ifdef DEBUG_REFCOUNT
163 GST_CAT_LOG (GST_CAT_CAPS, "freeing caps %p", caps);
165 g_slice_free1 (GST_MINI_OBJECT_SIZE (caps), caps);
169 gst_caps_init (GstCaps * caps, gsize size)
171 gst_mini_object_init (GST_MINI_OBJECT_CAST (caps), _gst_caps_type, size);
173 caps->mini_object.copy = (GstMiniObjectCopyFunction) _gst_caps_copy;
174 caps->mini_object.dispose = NULL;
175 caps->mini_object.free = (GstMiniObjectFreeFunction) _gst_caps_free;
177 /* the 32 has been determined by logging caps sizes in _gst_caps_free
178 * but g_ptr_array uses 16 anyway if it expands once, so this does not help
180 * caps->structs = g_ptr_array_sized_new (32);
182 caps->structs = g_ptr_array_new ();
186 * gst_caps_new_empty:
188 * Creates a new #GstCaps that is empty. That is, the returned
189 * #GstCaps contains no media formats.
190 * Caller is responsible for unreffing the returned caps.
192 * Returns: (transfer full): the new #GstCaps
195 gst_caps_new_empty (void)
199 caps = g_slice_new (GstCaps);
201 gst_caps_init (caps, sizeof (GstCaps));
203 #ifdef DEBUG_REFCOUNT
204 GST_CAT_LOG (GST_CAT_CAPS, "created caps %p", caps);
213 * Creates a new #GstCaps that indicates that it is compatible with
216 * Returns: (transfer full): the new #GstCaps
219 gst_caps_new_any (void)
221 GstCaps *caps = gst_caps_new_empty ();
223 GST_CAPS_FLAG_SET (caps, GST_CAPS_FLAGS_ANY);
229 * gst_caps_new_simple:
230 * @media_type: the media type of the structure
231 * @fieldname: first field to set
232 * @...: additional arguments
234 * Creates a new #GstCaps that contains one #GstStructure. The
235 * structure is defined by the arguments, which have the same format
236 * as gst_structure_new().
237 * Caller is responsible for unreffing the returned caps.
239 * Returns: (transfer full): the new #GstCaps
242 gst_caps_new_simple (const char *media_type, const char *fieldname, ...)
245 GstStructure *structure;
248 caps = gst_caps_new_empty ();
250 va_start (var_args, fieldname);
251 structure = gst_structure_new_valist (media_type, fieldname, var_args);
255 gst_caps_append_structure_unchecked (caps, structure);
257 gst_caps_replace (&caps, NULL);
264 * @struct1: the first structure to add
265 * @...: additional structures to add
267 * Creates a new #GstCaps and adds all the structures listed as
268 * arguments. The list must be NULL-terminated. The structures
269 * are not copied; the returned #GstCaps owns the structures.
271 * Returns: (transfer full): the new #GstCaps
274 gst_caps_new_full (GstStructure * struct1, ...)
279 va_start (var_args, struct1);
280 caps = gst_caps_new_full_valist (struct1, var_args);
287 * gst_caps_new_full_valist:
288 * @structure: the first structure to add
289 * @var_args: additional structures to add
291 * Creates a new #GstCaps and adds all the structures listed as
292 * arguments. The list must be NULL-terminated. The structures
293 * are not copied; the returned #GstCaps owns the structures.
295 * Returns: (transfer full): the new #GstCaps
298 gst_caps_new_full_valist (GstStructure * structure, va_list var_args)
302 caps = gst_caps_new_empty ();
305 gst_caps_append_structure_unchecked (caps, structure);
306 structure = va_arg (var_args, GstStructure *);
313 gst_static_caps_get_type (void)
315 static GType staticcaps_type = 0;
317 if (G_UNLIKELY (staticcaps_type == 0)) {
318 staticcaps_type = g_pointer_type_register_static ("GstStaticCaps");
320 return staticcaps_type;
325 * gst_static_caps_get:
326 * @static_caps: the #GstStaticCaps to convert
328 * Converts a #GstStaticCaps to a #GstCaps.
330 * Returns: (transfer full): a pointer to the #GstCaps. Unref after usage.
331 * Since the core holds an additional ref to the returned caps,
332 * use gst_caps_make_writable() on the returned caps to modify it.
335 gst_static_caps_get (GstStaticCaps * static_caps)
339 g_return_val_if_fail (static_caps != NULL, NULL);
341 caps = (GstCaps *) static_caps;
343 /* refcount is 0 when we need to convert */
344 if (G_UNLIKELY (GST_CAPS_REFCOUNT_VALUE (caps) == 0)) {
348 G_LOCK (static_caps_lock);
349 /* check if other thread already updated */
350 if (G_UNLIKELY (GST_CAPS_REFCOUNT_VALUE (caps) > 0))
353 string = static_caps->string;
355 if (G_UNLIKELY (string == NULL))
358 GST_CAT_LOG (GST_CAT_CAPS, "creating %p", static_caps);
360 /* we construct the caps on the stack, then copy over the struct into our
361 * real caps, refcount last. We do this because we must leave the refcount
362 * of the result caps to 0 so that other threads don't run away with the
363 * caps while we are constructing it. */
364 gst_caps_init (&temp, sizeof (GstCaps));
366 /* convert to string */
367 if (G_UNLIKELY (!gst_caps_from_string_inplace (&temp, string)))
368 g_critical ("Could not convert static caps \"%s\"", string);
370 gst_caps_init (caps, sizeof (GstCaps));
371 /* now copy stuff over to the real caps. */
372 GST_CAPS_FLAGS (caps) = GST_CAPS_FLAGS (&temp);
373 caps->structs = temp.structs;
375 GST_CAT_LOG (GST_CAT_CAPS, "created %p", static_caps);
377 G_UNLOCK (static_caps_lock);
379 /* ref the caps, makes it not writable */
387 G_UNLOCK (static_caps_lock);
388 g_warning ("static caps %p string is NULL", static_caps);
395 static GstStructure *
396 gst_caps_remove_and_get_structure (GstCaps * caps, guint idx)
398 /* don't use index_fast, gst_caps_do_simplify relies on the order */
399 GstStructure *s = g_ptr_array_remove_index (caps->structs, idx);
401 gst_structure_set_parent_refcount (s, NULL);
406 * gst_caps_steal_structure:
407 * @caps: the #GstCaps to retrieve from
408 * @index: Index of the structure to retrieve
410 * Retrieves the stucture with the given index from the list of structures
411 * contained in @caps. The caller becomes the owner of the returned structure.
413 * Returns: (transfer full): a pointer to the #GstStructure corresponding
419 gst_caps_steal_structure (GstCaps * caps, guint index)
421 g_return_val_if_fail (caps != NULL, NULL);
422 g_return_val_if_fail (IS_WRITABLE (caps), NULL);
424 if (G_UNLIKELY (index >= caps->structs->len))
427 return gst_caps_remove_and_get_structure (caps, index);
432 * @caps1: the #GstCaps that will be appended to
433 * @caps2: (transfer full): the #GstCaps to append
435 * Appends the structures contained in @caps2 to @caps1. The structures in
436 * @caps2 are not copied -- they are transferred to @caps1, and then @caps2 is
437 * freed. If either caps is ANY, the resulting caps will be ANY.
440 gst_caps_append (GstCaps * caps1, GstCaps * caps2)
442 GstStructure *structure;
445 g_return_if_fail (GST_IS_CAPS (caps1));
446 g_return_if_fail (GST_IS_CAPS (caps2));
447 g_return_if_fail (IS_WRITABLE (caps1));
448 g_return_if_fail (IS_WRITABLE (caps2));
450 if (G_UNLIKELY (CAPS_IS_ANY (caps1) || CAPS_IS_ANY (caps2))) {
451 /* FIXME: this leaks */
452 GST_CAPS_FLAGS (caps1) |= GST_CAPS_FLAGS_ANY;
453 for (i = caps2->structs->len - 1; i >= 0; i--) {
454 structure = gst_caps_remove_and_get_structure (caps2, i);
455 gst_structure_free (structure);
458 for (i = caps2->structs->len; i; i--) {
459 structure = gst_caps_remove_and_get_structure (caps2, 0);
460 gst_caps_append_structure_unchecked (caps1, structure);
463 gst_caps_unref (caps2); /* guaranteed to free it */
468 * @caps1: the #GstCaps that will take the new entries
469 * @caps2: (transfer full): the #GstCaps to merge in
471 * Appends the structures contained in @caps2 to @caps1 if they are not yet
472 * expressed by @caps1. The structures in @caps2 are not copied -- they are
473 * transferred to @caps1, and then @caps2 is freed.
474 * If either caps is ANY, the resulting caps will be ANY.
479 gst_caps_merge (GstCaps * caps1, GstCaps * caps2)
481 GstStructure *structure;
484 g_return_if_fail (GST_IS_CAPS (caps1));
485 g_return_if_fail (GST_IS_CAPS (caps2));
486 g_return_if_fail (IS_WRITABLE (caps1));
487 g_return_if_fail (IS_WRITABLE (caps2));
489 if (G_UNLIKELY (CAPS_IS_ANY (caps1))) {
490 for (i = caps2->structs->len - 1; i >= 0; i--) {
491 structure = gst_caps_remove_and_get_structure (caps2, i);
492 gst_structure_free (structure);
494 } else if (G_UNLIKELY (CAPS_IS_ANY (caps2))) {
495 GST_CAPS_FLAGS (caps1) |= GST_CAPS_FLAGS_ANY;
496 for (i = caps1->structs->len - 1; i >= 0; i--) {
497 structure = gst_caps_remove_and_get_structure (caps1, i);
498 gst_structure_free (structure);
501 for (i = caps2->structs->len; i; i--) {
502 structure = gst_caps_remove_and_get_structure (caps2, 0);
503 gst_caps_merge_structure (caps1, structure);
506 GstCaps *com = gst_caps_intersect (caps1, caps2);
507 GstCaps *add = gst_caps_subtract (caps2, com);
509 GST_DEBUG ("common : %d", gst_caps_get_size (com));
510 GST_DEBUG ("adding : %d", gst_caps_get_size (add));
511 gst_caps_append (caps1, add);
512 gst_caps_unref (com);
515 gst_caps_unref (caps2); /* guaranteed to free it */
519 * gst_caps_append_structure:
520 * @caps: the #GstCaps that will be appended to
521 * @structure: (transfer full): the #GstStructure to append
523 * Appends @structure to @caps. The structure is not copied; @caps
524 * becomes the owner of @structure.
527 gst_caps_append_structure (GstCaps * caps, GstStructure * structure)
529 g_return_if_fail (GST_IS_CAPS (caps));
530 g_return_if_fail (IS_WRITABLE (caps));
532 if (G_LIKELY (structure)) {
533 gst_caps_append_structure_unchecked (caps, structure);
538 * gst_caps_remove_structure:
539 * @caps: the #GstCaps to remove from
540 * @idx: Index of the structure to remove
542 * removes the stucture with the given index from the list of structures
543 * contained in @caps.
546 gst_caps_remove_structure (GstCaps * caps, guint idx)
548 GstStructure *structure;
550 g_return_if_fail (caps != NULL);
551 g_return_if_fail (idx <= gst_caps_get_size (caps));
552 g_return_if_fail (IS_WRITABLE (caps));
554 structure = gst_caps_remove_and_get_structure (caps, idx);
555 gst_structure_free (structure);
559 * gst_caps_merge_structure:
560 * @caps: the #GstCaps that will the the new structure
561 * @structure: (transfer full): the #GstStructure to merge
563 * Appends @structure to @caps if its not already expressed by @caps. The
564 * structure is not copied; @caps becomes the owner of @structure.
567 gst_caps_merge_structure (GstCaps * caps, GstStructure * structure)
569 g_return_if_fail (GST_IS_CAPS (caps));
570 g_return_if_fail (IS_WRITABLE (caps));
572 if (G_LIKELY (structure)) {
573 GstStructure *structure1;
575 gboolean unique = TRUE;
577 /* check each structure */
578 for (i = caps->structs->len - 1; i >= 0; i--) {
579 structure1 = gst_caps_get_structure_unchecked (caps, i);
580 /* if structure is a subset of structure1, then skip it */
581 if (gst_structure_is_subset (structure, structure1)) {
587 gst_caps_append_structure_unchecked (caps, structure);
589 gst_structure_free (structure);
598 * Gets the number of structures contained in @caps.
600 * Returns: the number of structures that @caps contains
603 gst_caps_get_size (const GstCaps * caps)
605 g_return_val_if_fail (GST_IS_CAPS (caps), 0);
607 return caps->structs->len;
611 * gst_caps_get_structure:
613 * @index: the index of the structure
615 * Finds the structure in @caps that has the index @index, and
618 * WARNING: This function takes a const GstCaps *, but returns a
619 * non-const GstStructure *. This is for programming convenience --
620 * the caller should be aware that structures inside a constant
621 * #GstCaps should not be modified. However, if you know the caps
622 * are writable, either because you have just copied them or made
623 * them writable with gst_caps_make_writable(), you may modify the
624 * structure returned in the usual way, e.g. with functions like
625 * gst_structure_set().
627 * You do not need to free or unref the structure returned, it
628 * belongs to the #GstCaps.
630 * Returns: (transfer none): a pointer to the #GstStructure corresponding
634 gst_caps_get_structure (const GstCaps * caps, guint index)
636 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
637 g_return_val_if_fail (index < caps->structs->len, NULL);
639 return gst_caps_get_structure_unchecked (caps, index);
644 * @caps: the #GstCaps to copy
645 * @nth: the nth structure to copy
647 * Creates a new #GstCaps and appends a copy of the nth structure
648 * contained in @caps.
650 * Returns: (transfer full): the new #GstCaps
653 gst_caps_copy_nth (const GstCaps * caps, guint nth)
656 GstStructure *structure;
658 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
660 newcaps = gst_caps_new_empty ();
661 GST_CAPS_FLAGS (newcaps) = GST_CAPS_FLAGS (caps);
663 if (G_LIKELY (caps->structs->len > nth)) {
664 structure = gst_caps_get_structure_unchecked (caps, nth);
665 gst_caps_append_structure_unchecked (newcaps,
666 gst_structure_copy (structure));
674 * @caps: the #GstCaps to truncate
676 * Destructively discard all but the first structure from @caps. Useful when
677 * fixating. @caps must be writable.
680 gst_caps_truncate (GstCaps * caps)
684 g_return_if_fail (GST_IS_CAPS (caps));
685 g_return_if_fail (IS_WRITABLE (caps));
687 i = caps->structs->len - 1;
690 gst_caps_remove_structure (caps, i--);
694 * gst_caps_set_value:
695 * @caps: a writable caps
696 * @field: name of the field to set
697 * @value: value to set the field to
699 * Sets the given @field on all structures of @caps to the given @value.
700 * This is a convenience function for calling gst_structure_set_value() on
701 * all structures of @caps.
706 gst_caps_set_value (GstCaps * caps, const char *field, const GValue * value)
710 g_return_if_fail (GST_IS_CAPS (caps));
711 g_return_if_fail (IS_WRITABLE (caps));
712 g_return_if_fail (field != NULL);
713 g_return_if_fail (G_IS_VALUE (value));
715 len = caps->structs->len;
716 for (i = 0; i < len; i++) {
717 GstStructure *structure = gst_caps_get_structure_unchecked (caps, i);
718 gst_structure_set_value (structure, field, value);
723 * gst_caps_set_simple_valist:
724 * @caps: the #GstCaps to set
725 * @field: first field to set
726 * @varargs: additional parameters
728 * Sets fields in a #GstCaps. The arguments must be passed in the same
729 * manner as gst_structure_set(), and be NULL-terminated.
730 * <note>Prior to GStreamer version 0.10.26, this function failed when
731 * @caps was not simple. If your code needs to work with those versions
732 * of GStreamer, you may only call this function when GST_CAPS_IS_SIMPLE()
733 * is %TRUE for @caps.</note>
736 gst_caps_set_simple_valist (GstCaps * caps, const char *field, va_list varargs)
738 GValue value = { 0, };
740 g_return_if_fail (GST_IS_CAPS (caps));
741 g_return_if_fail (IS_WRITABLE (caps));
747 type = va_arg (varargs, GType);
749 if (G_UNLIKELY (type == G_TYPE_DATE)) {
750 g_warning ("Don't use G_TYPE_DATE, use GST_TYPE_DATE instead\n");
751 type = GST_TYPE_DATE;
753 G_VALUE_COLLECT_INIT (&value, type, varargs, 0, &err);
754 if (G_UNLIKELY (err)) {
755 g_critical ("%s", err);
759 gst_caps_set_value (caps, field, &value);
761 g_value_unset (&value);
763 field = va_arg (varargs, const gchar *);
768 * gst_caps_set_simple:
769 * @caps: the #GstCaps to set
770 * @field: first field to set
771 * @...: additional parameters
773 * Sets fields in a #GstCaps. The arguments must be passed in the same
774 * manner as gst_structure_set(), and be NULL-terminated.
775 * <note>Prior to GStreamer version 0.10.26, this function failed when
776 * @caps was not simple. If your code needs to work with those versions
777 * of GStreamer, you may only call this function when GST_CAPS_IS_SIMPLE()
778 * is %TRUE for @caps.</note>
781 gst_caps_set_simple (GstCaps * caps, const char *field, ...)
785 g_return_if_fail (GST_IS_CAPS (caps));
786 g_return_if_fail (IS_WRITABLE (caps));
788 va_start (var_args, field);
789 gst_caps_set_simple_valist (caps, field, var_args);
797 * @caps: the #GstCaps to test
799 * Determines if @caps represents any media format.
801 * Returns: TRUE if @caps represents any format.
804 gst_caps_is_any (const GstCaps * caps)
806 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
808 return (CAPS_IS_ANY (caps));
813 * @caps: the #GstCaps to test
815 * Determines if @caps represents no media formats.
817 * Returns: TRUE if @caps represents no formats.
820 gst_caps_is_empty (const GstCaps * caps)
822 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
824 if (CAPS_IS_ANY (caps))
827 return CAPS_IS_EMPTY_SIMPLE (caps);
831 gst_caps_is_fixed_foreach (GQuark field_id, const GValue * value,
834 return gst_value_is_fixed (value);
839 * @caps: the #GstCaps to test
841 * Fixed #GstCaps describe exactly one format, that is, they have exactly
842 * one structure, and each field in the structure describes a fixed type.
843 * Examples of non-fixed types are GST_TYPE_INT_RANGE and GST_TYPE_LIST.
845 * Returns: TRUE if @caps is fixed
848 gst_caps_is_fixed (const GstCaps * caps)
850 GstStructure *structure;
852 g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
854 if (caps->structs->len != 1)
857 structure = gst_caps_get_structure_unchecked (caps, 0);
859 return gst_structure_foreach (structure, gst_caps_is_fixed_foreach, NULL);
863 * gst_caps_is_equal_fixed:
864 * @caps1: the #GstCaps to test
865 * @caps2: the #GstCaps to test
867 * Tests if two #GstCaps are equal. This function only works on fixed
870 * Returns: TRUE if the arguments represent the same format
873 gst_caps_is_equal_fixed (const GstCaps * caps1, const GstCaps * caps2)
875 GstStructure *struct1, *struct2;
877 g_return_val_if_fail (gst_caps_is_fixed (caps1), FALSE);
878 g_return_val_if_fail (gst_caps_is_fixed (caps2), FALSE);
880 struct1 = gst_caps_get_structure_unchecked (caps1, 0);
881 struct2 = gst_caps_get_structure_unchecked (caps2, 0);
883 return gst_structure_is_equal (struct1, struct2);
887 * gst_caps_is_always_compatible:
888 * @caps1: the #GstCaps to test
889 * @caps2: the #GstCaps to test
891 * A given #GstCaps structure is always compatible with another if
892 * every media format that is in the first is also contained in the
893 * second. That is, @caps1 is a subset of @caps2.
895 * Returns: TRUE if @caps1 is a subset of @caps2.
898 gst_caps_is_always_compatible (const GstCaps * caps1, const GstCaps * caps2)
900 g_return_val_if_fail (GST_IS_CAPS (caps1), FALSE);
901 g_return_val_if_fail (GST_IS_CAPS (caps2), FALSE);
903 return gst_caps_is_subset (caps1, caps2);
907 * gst_caps_is_subset:
908 * @subset: a #GstCaps
909 * @superset: a potentially greater #GstCaps
911 * Checks if all caps represented by @subset are also represented by @superset.
912 * <note>This function does not work reliably if optional properties for caps
913 * are included on one caps and omitted on the other.</note>
915 * Returns: %TRUE if @subset is a subset of @superset
918 gst_caps_is_subset (const GstCaps * subset, const GstCaps * superset)
920 GstStructure *s1, *s2;
924 g_return_val_if_fail (subset != NULL, FALSE);
925 g_return_val_if_fail (superset != NULL, FALSE);
927 if (CAPS_IS_EMPTY (subset) || CAPS_IS_ANY (superset))
929 if (CAPS_IS_ANY (subset) || CAPS_IS_EMPTY (superset))
932 for (i = subset->structs->len - 1; i >= 0; i--) {
933 for (j = superset->structs->len - 1; j >= 0; j--) {
934 s1 = gst_caps_get_structure_unchecked (subset, i);
935 s2 = gst_caps_get_structure_unchecked (superset, j);
936 if (gst_structure_is_subset (s1, s2)) {
937 /* If we found a superset, continue with the next
938 * subset structure */
942 /* If we found no superset for this subset structure
943 * we return FALSE immediately */
954 * gst_caps_is_subset_structure:
956 * @structure: a potential #GstStructure subset of @caps
958 * Checks if @structure is a subset of @caps. See gst_caps_is_subset()
959 * for more information.
961 * Returns: %TRUE if @structure is a subset of @caps
966 gst_caps_is_subset_structure (const GstCaps * caps,
967 const GstStructure * structure)
972 g_return_val_if_fail (caps != NULL, FALSE);
973 g_return_val_if_fail (structure != NULL, FALSE);
975 if (CAPS_IS_ANY (caps))
977 if (CAPS_IS_EMPTY (caps))
980 for (i = caps->structs->len - 1; i >= 0; i--) {
981 s = gst_caps_get_structure_unchecked (caps, i);
982 if (gst_structure_is_subset (structure, s)) {
983 /* If we found a superset return TRUE */
994 * @caps2: another #GstCaps
996 * Checks if the given caps represent the same set of caps.
997 * <note>This function does not work reliably if optional properties for caps
998 * are included on one caps and omitted on the other.</note>
1000 * This function deals correctly with passing NULL for any of the caps.
1002 * Returns: TRUE if both caps are equal.
1005 gst_caps_is_equal (const GstCaps * caps1, const GstCaps * caps2)
1007 /* FIXME 0.11: NULL pointers are no valid Caps but indicate an error
1008 * So there should be an assertion that caps1 and caps2 != NULL */
1010 /* NULL <-> NULL is allowed here */
1011 if (G_UNLIKELY (caps1 == caps2))
1014 /* one of them NULL => they are different (can't be both NULL because
1015 * we checked that above) */
1016 if (G_UNLIKELY (caps1 == NULL || caps2 == NULL))
1019 if (G_UNLIKELY (gst_caps_is_fixed (caps1) && gst_caps_is_fixed (caps2)))
1020 return gst_caps_is_equal_fixed (caps1, caps2);
1022 return gst_caps_is_subset (caps1, caps2) && gst_caps_is_subset (caps2, caps1);
1025 /* intersect operation */
1028 * gst_caps_can_intersect:
1029 * @caps1: a #GstCaps to intersect
1030 * @caps2: a #GstCaps to intersect
1032 * Tries intersecting @caps1 and @caps2 and reports whether the result would not
1035 * Returns: %TRUE if intersection would be not empty
1040 gst_caps_can_intersect (const GstCaps * caps1, const GstCaps * caps2)
1042 guint64 i; /* index can be up to 2 * G_MAX_UINT */
1043 guint j, k, len1, len2;
1044 GstStructure *struct1;
1045 GstStructure *struct2;
1047 g_return_val_if_fail (GST_IS_CAPS (caps1), FALSE);
1048 g_return_val_if_fail (GST_IS_CAPS (caps2), FALSE);
1050 /* caps are exactly the same pointers */
1051 if (G_UNLIKELY (caps1 == caps2))
1054 /* empty caps on either side, return empty */
1055 if (G_UNLIKELY (CAPS_IS_EMPTY (caps1) || CAPS_IS_EMPTY (caps2)))
1058 /* one of the caps is any */
1059 if (G_UNLIKELY (CAPS_IS_ANY (caps1) || CAPS_IS_ANY (caps2)))
1062 /* run zigzag on top line then right line, this preserves the caps order
1063 * much better than a simple loop.
1065 * This algorithm zigzags over the caps structures as demonstrated in
1066 * the folowing matrix:
1069 * +------------- total distance: +-------------
1070 * | 1 2 4 7 0 | 0 1 2 3
1071 * caps2 | 3 5 8 10 1 | 1 2 3 4
1072 * | 6 9 11 12 2 | 2 3 4 5
1074 * First we iterate over the caps1 structures (top line) intersecting
1075 * the structures diagonally down, then we iterate over the caps2
1076 * structures. The result is that the intersections are ordered based on the
1077 * sum of the indexes in the list.
1079 len1 = caps1->structs->len;
1080 len2 = caps2->structs->len;
1081 for (i = 0; i < len1 + len2 - 1; i++) {
1082 /* superset index goes from 0 to sgst_caps_structure_intersectuperset->structs->len-1 */
1083 j = MIN (i, len1 - 1);
1084 /* subset index stays 0 until i reaches superset->structs->len, then it
1085 * counts up from 1 to subset->structs->len - 1 */
1088 /* now run the diagonal line, end condition is the left or bottom
1091 struct1 = gst_caps_get_structure_unchecked (caps1, j);
1092 struct2 = gst_caps_get_structure_unchecked (caps2, k);
1094 if (gst_structure_can_intersect (struct1, struct2)) {
1097 /* move down left */
1099 if (G_UNLIKELY (j == 0))
1100 break; /* so we don't roll back to G_MAXUINT */
1108 gst_caps_intersect_zig_zag (const GstCaps * caps1, const GstCaps * caps2)
1110 guint64 i; /* index can be up to 2 * G_MAX_UINT */
1111 guint j, k, len1, len2;
1113 GstStructure *struct1;
1114 GstStructure *struct2;
1116 GstStructure *istruct;
1118 /* caps are exactly the same pointers, just copy one caps */
1119 if (G_UNLIKELY (caps1 == caps2))
1120 return _gst_caps_copy (caps1);
1122 /* empty caps on either side, return empty */
1123 if (G_UNLIKELY (CAPS_IS_EMPTY (caps1) || CAPS_IS_EMPTY (caps2)))
1124 return gst_caps_new_empty ();
1126 /* one of the caps is any, just copy the other caps */
1127 if (G_UNLIKELY (CAPS_IS_ANY (caps1)))
1128 return _gst_caps_copy (caps2);
1129 if (G_UNLIKELY (CAPS_IS_ANY (caps2)))
1130 return _gst_caps_copy (caps1);
1132 dest = gst_caps_new_empty ();
1134 /* run zigzag on top line then right line, this preserves the caps order
1135 * much better than a simple loop.
1137 * This algorithm zigzags over the caps structures as demonstrated in
1138 * the folowing matrix:
1146 * First we iterate over the caps1 structures (top line) intersecting
1147 * the structures diagonally down, then we iterate over the caps2
1150 len1 = caps1->structs->len;
1151 len2 = caps2->structs->len;
1152 for (i = 0; i < len1 + len2 - 1; i++) {
1153 /* caps1 index goes from 0 to caps1->structs->len-1 */
1154 j = MIN (i, len1 - 1);
1155 /* caps2 index stays 0 until i reaches caps1->structs->len, then it counts
1156 * up from 1 to caps2->structs->len - 1 */
1159 /* now run the diagonal line, end condition is the left or bottom
1162 struct1 = gst_caps_get_structure_unchecked (caps1, j);
1163 struct2 = gst_caps_get_structure_unchecked (caps2, k);
1165 istruct = gst_structure_intersect (struct1, struct2);
1167 gst_caps_merge_structure (dest, istruct);
1168 /* move down left */
1170 if (G_UNLIKELY (j == 0))
1171 break; /* so we don't roll back to G_MAXUINT */
1179 * gst_caps_intersect_first:
1180 * @caps1: a #GstCaps to intersect
1181 * @caps2: a #GstCaps to intersect
1183 * Creates a new #GstCaps that contains all the formats that are common
1184 * to both @caps1 and @caps2.
1186 * Unlike @gst_caps_intersect, the returned caps will be ordered in a similar
1187 * fashion as @caps1.
1189 * Returns: the new #GstCaps
1192 gst_caps_intersect_first (const GstCaps * caps1, const GstCaps * caps2)
1194 guint64 i; /* index can be up to 2 * G_MAX_UINT */
1195 guint j, len1, len2;
1197 GstStructure *struct1;
1198 GstStructure *struct2;
1200 GstStructure *istruct;
1202 /* caps are exactly the same pointers, just copy one caps */
1203 if (G_UNLIKELY (caps1 == caps2))
1204 return gst_caps_copy (caps1);
1206 /* empty caps on either side, return empty */
1207 if (G_UNLIKELY (CAPS_IS_EMPTY (caps1) || CAPS_IS_EMPTY (caps2)))
1208 return gst_caps_new_empty ();
1210 /* one of the caps is any, just copy the other caps */
1211 if (G_UNLIKELY (CAPS_IS_ANY (caps1)))
1212 return gst_caps_copy (caps2);
1213 if (G_UNLIKELY (CAPS_IS_ANY (caps2)))
1214 return gst_caps_copy (caps1);
1216 dest = gst_caps_new_empty ();
1218 len1 = caps1->structs->len;
1219 len2 = caps2->structs->len;
1220 for (i = 0; i < len1; i++) {
1221 struct1 = gst_caps_get_structure_unchecked (caps1, i);
1222 for (j = 0; j < len2; j++) {
1223 struct2 = gst_caps_get_structure_unchecked (caps2, j);
1224 istruct = gst_structure_intersect (struct1, struct2);
1226 gst_caps_merge_structure (dest, istruct);
1234 * gst_caps_intersect_full:
1235 * @caps1: a #GstCaps to intersect
1236 * @caps2: a #GstCaps to intersect
1237 * @mode: The intersection algorithm/mode to use
1239 * Creates a new #GstCaps that contains all the formats that are common
1240 * to both @caps1 and @caps2, the order is defined by the #GstCapsIntersectMode
1243 * Returns: the new #GstCaps
1247 gst_caps_intersect_full (const GstCaps * caps1, const GstCaps * caps2,
1248 GstCapsIntersectMode mode)
1250 g_return_val_if_fail (GST_IS_CAPS (caps1), NULL);
1251 g_return_val_if_fail (GST_IS_CAPS (caps2), NULL);
1254 case GST_CAPS_INTERSECT_FIRST:
1255 return gst_caps_intersect_first (caps1, caps2);
1257 g_warning ("Unknown caps intersect mode: %d", mode);
1259 case GST_CAPS_INTERSECT_ZIG_ZAG:
1260 return gst_caps_intersect_zig_zag (caps1, caps2);
1265 * gst_caps_intersect:
1266 * @caps1: a #GstCaps to intersect
1267 * @caps2: a #GstCaps to intersect
1269 * Creates a new #GstCaps that contains all the formats that are common
1270 * to both @caps1 and @caps2. Defaults to %GST_CAPS_INTERSECT_ZIG_ZAG mode.
1272 * Returns: the new #GstCaps
1275 gst_caps_intersect (const GstCaps * caps1, const GstCaps * caps2)
1277 return gst_caps_intersect_full (caps1, caps2, GST_CAPS_INTERSECT_ZIG_ZAG);
1281 /* subtract operation */
1285 const GstStructure *subtract_from;
1291 gst_caps_structure_subtract_field (GQuark field_id, const GValue * value,
1294 SubtractionEntry *e = user_data;
1295 GValue subtraction = { 0, };
1296 const GValue *other;
1297 GstStructure *structure;
1299 other = gst_structure_id_get_value (e->subtract_from, field_id);
1303 if (!gst_value_subtract (&subtraction, other, value))
1305 if (gst_value_compare (&subtraction, other) == GST_VALUE_EQUAL) {
1306 g_value_unset (&subtraction);
1309 structure = gst_structure_copy (e->subtract_from);
1310 gst_structure_id_set_value (structure, field_id, &subtraction);
1311 g_value_unset (&subtraction);
1312 e->put_into = g_slist_prepend (e->put_into, structure);
1318 gst_caps_structure_subtract (GSList ** into, const GstStructure * minuend,
1319 const GstStructure * subtrahend)
1324 e.subtract_from = minuend;
1327 ret = gst_structure_foreach ((GstStructure *) subtrahend,
1328 gst_caps_structure_subtract_field, &e);
1334 for (walk = e.put_into; walk; walk = g_slist_next (walk)) {
1335 gst_structure_free (walk->data);
1337 g_slist_free (e.put_into);
1343 * gst_caps_subtract:
1344 * @minuend: #GstCaps to substract from
1345 * @subtrahend: #GstCaps to substract
1347 * Subtracts the @subtrahend from the @minuend.
1348 * <note>This function does not work reliably if optional properties for caps
1349 * are included on one caps and omitted on the other.</note>
1351 * Returns: the resulting caps
1354 gst_caps_subtract (const GstCaps * minuend, const GstCaps * subtrahend)
1359 GstCaps *dest = NULL, *src;
1361 g_return_val_if_fail (minuend != NULL, NULL);
1362 g_return_val_if_fail (subtrahend != NULL, NULL);
1364 if (CAPS_IS_EMPTY (minuend) || CAPS_IS_ANY (subtrahend)) {
1365 return gst_caps_new_empty ();
1367 if (CAPS_IS_EMPTY_SIMPLE (subtrahend))
1368 return _gst_caps_copy (minuend);
1370 /* FIXME: Do we want this here or above?
1371 The reason we need this is that there is no definition about what
1372 ANY means for specific types, so it's not possible to reduce ANY partially
1373 You can only remove everything or nothing and that is done above.
1374 Note: there's a test that checks this behaviour. */
1375 g_return_val_if_fail (!CAPS_IS_ANY (minuend), NULL);
1376 sublen = subtrahend->structs->len;
1377 g_assert (sublen > 0);
1379 src = _gst_caps_copy (minuend);
1380 for (i = 0; i < sublen; i++) {
1383 sub = gst_caps_get_structure_unchecked (subtrahend, i);
1385 gst_caps_unref (src);
1388 dest = gst_caps_new_empty ();
1389 srclen = src->structs->len;
1390 for (j = 0; j < srclen; j++) {
1391 min = gst_caps_get_structure_unchecked (src, j);
1392 if (gst_structure_get_name_id (min) == gst_structure_get_name_id (sub)) {
1395 if (gst_caps_structure_subtract (&list, min, sub)) {
1398 for (walk = list; walk; walk = g_slist_next (walk)) {
1399 gst_caps_append_structure_unchecked (dest,
1400 (GstStructure *) walk->data);
1402 g_slist_free (list);
1404 gst_caps_append_structure_unchecked (dest, gst_structure_copy (min));
1407 gst_caps_append_structure_unchecked (dest, gst_structure_copy (min));
1410 if (CAPS_IS_EMPTY_SIMPLE (dest)) {
1411 gst_caps_unref (src);
1416 gst_caps_unref (src);
1417 gst_caps_do_simplify (dest);
1421 /* union operation */
1424 static GstStructure *
1425 gst_caps_structure_union (const GstStructure * struct1,
1426 const GstStructure * struct2)
1430 const GstStructureField *field1;
1431 const GstStructureField *field2;
1434 /* FIXME this doesn't actually work */
1436 if (struct1->name != struct2->name)
1439 dest = gst_structure_id_empty_new (struct1->name);
1441 for (i = 0; i < struct1->fields->len; i++) {
1442 GValue dest_value = { 0 };
1444 field1 = GST_STRUCTURE_FIELD (struct1, i);
1445 field2 = gst_structure_id_get_field (struct2, field1->name);
1447 if (field2 == NULL) {
1450 if (gst_value_union (&dest_value, &field1->value, &field2->value)) {
1451 gst_structure_set_value (dest, g_quark_to_string (field1->name),
1454 ret = gst_value_compare (&field1->value, &field2->value);
1465 * @caps1: a #GstCaps to union
1466 * @caps2: a #GstCaps to union
1468 * Creates a new #GstCaps that contains all the formats that are in
1469 * either @caps1 and @caps2.
1471 * Returns: the new #GstCaps
1474 gst_caps_union (const GstCaps * caps1, const GstCaps * caps2)
1479 /* NULL pointers are no correct GstCaps */
1480 g_return_val_if_fail (caps1 != NULL, NULL);
1481 g_return_val_if_fail (caps2 != NULL, NULL);
1483 if (CAPS_IS_EMPTY (caps1))
1484 return _gst_caps_copy (caps2);
1486 if (CAPS_IS_EMPTY (caps2))
1487 return _gst_caps_copy (caps1);
1489 if (CAPS_IS_ANY (caps1) || CAPS_IS_ANY (caps2))
1490 return gst_caps_new_any ();
1492 dest1 = _gst_caps_copy (caps1);
1493 dest2 = _gst_caps_copy (caps2);
1494 gst_caps_append (dest1, dest2);
1496 gst_caps_do_simplify (dest1);
1500 /* normalize/simplify operations */
1502 typedef struct _NormalizeForeach
1505 GstStructure *structure;
1510 gst_caps_normalize_foreach (GQuark field_id, const GValue * value, gpointer ptr)
1512 NormalizeForeach *nf = (NormalizeForeach *) ptr;
1516 if (G_VALUE_TYPE (value) == GST_TYPE_LIST) {
1517 guint len = gst_value_list_get_size (value);
1518 for (i = 1; i < len; i++) {
1519 const GValue *v = gst_value_list_get_value (value, i);
1520 GstStructure *structure = gst_structure_copy (nf->structure);
1522 gst_structure_id_set_value (structure, field_id, v);
1523 gst_caps_append_structure_unchecked (nf->caps, structure);
1526 gst_value_init_and_copy (&val, gst_value_list_get_value (value, 0));
1527 gst_structure_id_set_value (nf->structure, field_id, &val);
1528 g_value_unset (&val);
1536 * gst_caps_normalize:
1537 * @caps: a #GstCaps to normalize
1539 * Creates a new #GstCaps that represents the same set of formats as
1540 * @caps, but contains no lists. Each list is expanded into separate
1543 * Returns: the new #GstCaps
1546 gst_caps_normalize (const GstCaps * caps)
1548 NormalizeForeach nf;
1552 g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
1554 newcaps = _gst_caps_copy (caps);
1557 for (i = 0; i < gst_caps_get_size (newcaps); i++) {
1558 nf.structure = gst_caps_get_structure_unchecked (newcaps, i);
1560 while (!gst_structure_foreach (nf.structure,
1561 gst_caps_normalize_foreach, &nf));
1568 gst_caps_compare_structures (gconstpointer one, gconstpointer two)
1571 const GstStructure *struct1 = *((const GstStructure **) one);
1572 const GstStructure *struct2 = *((const GstStructure **) two);
1574 /* FIXME: this orders alphabetically, but ordering the quarks might be faster
1575 So what's the best way? */
1576 ret = strcmp (gst_structure_get_name (struct1),
1577 gst_structure_get_name (struct2));
1581 return gst_structure_n_fields (struct2) - gst_structure_n_fields (struct1);
1588 GstStructure *compare;
1593 gst_caps_structure_figure_out_union (GQuark field_id, const GValue * value,
1596 UnionField *u = user_data;
1597 const GValue *val = gst_structure_id_get_value (u->compare, field_id);
1601 g_value_unset (&u->value);
1604 if (gst_value_compare (val, value) == GST_VALUE_EQUAL)
1607 g_value_unset (&u->value);
1611 gst_value_union (&u->value, val, value);
1616 gst_caps_structure_simplify (GstStructure ** result,
1617 const GstStructure * simplify, GstStructure * compare)
1620 UnionField field = { 0, {0,}, NULL };
1622 /* try to subtract to get a real subset */
1623 if (gst_caps_structure_subtract (&list, simplify, compare)) {
1624 if (list == NULL) { /* no result */
1627 } else if (list->next == NULL) { /* one result */
1628 *result = list->data;
1629 g_slist_free (list);
1631 } else { /* multiple results */
1632 g_slist_foreach (list, (GFunc) gst_structure_free, NULL);
1633 g_slist_free (list);
1638 /* try to union both structs */
1639 field.compare = compare;
1640 if (gst_structure_foreach ((GstStructure *) simplify,
1641 gst_caps_structure_figure_out_union, &field)) {
1642 gboolean ret = FALSE;
1644 /* now we know all of simplify's fields are the same in compare
1645 * but at most one field: field.name */
1646 if (G_IS_VALUE (&field.value)) {
1647 if (gst_structure_n_fields (simplify) == gst_structure_n_fields (compare)) {
1648 gst_structure_id_set_value (compare, field.name, &field.value);
1652 g_value_unset (&field.value);
1653 } else if (gst_structure_n_fields (simplify) <=
1654 gst_structure_n_fields (compare)) {
1655 /* compare is just more specific, will be optimized away later */
1656 /* FIXME: do this here? */
1657 GST_LOG ("found a case that will be optimized later.");
1659 gchar *one = gst_structure_to_string (simplify);
1660 gchar *two = gst_structure_to_string (compare);
1663 ("caps mismatch: structures %s and %s claim to be possible to unify, but aren't",
1675 gst_caps_switch_structures (GstCaps * caps, GstStructure * old,
1676 GstStructure * new, gint i)
1678 gst_structure_set_parent_refcount (old, NULL);
1679 gst_structure_free (old);
1680 gst_structure_set_parent_refcount (new, &GST_CAPS_REFCOUNT (caps));
1681 g_ptr_array_index (caps->structs, i) = new;
1685 * gst_caps_do_simplify:
1686 * @caps: a #GstCaps to simplify
1688 * Modifies the given @caps inplace into a representation that represents the
1689 * same set of formats, but in a simpler form. Component structures that are
1690 * identical are merged. Component structures that have values that can be
1691 * merged are also merged.
1693 * Returns: TRUE, if the caps could be simplified
1696 gst_caps_do_simplify (GstCaps * caps)
1698 GstStructure *simplify, *compare, *result = NULL;
1700 gboolean changed = FALSE;
1702 g_return_val_if_fail (caps != NULL, FALSE);
1703 g_return_val_if_fail (IS_WRITABLE (caps), FALSE);
1705 if (gst_caps_get_size (caps) < 2)
1708 g_ptr_array_sort (caps->structs, gst_caps_compare_structures);
1710 start = caps->structs->len - 1;
1711 for (i = caps->structs->len - 1; i >= 0; i--) {
1712 simplify = gst_caps_get_structure_unchecked (caps, i);
1713 if (gst_structure_get_name_id (simplify) !=
1714 gst_structure_get_name_id (gst_caps_get_structure_unchecked (caps,
1717 for (j = start; j >= 0; j--) {
1720 compare = gst_caps_get_structure_unchecked (caps, j);
1721 if (gst_structure_get_name_id (simplify) !=
1722 gst_structure_get_name_id (compare)) {
1725 if (gst_caps_structure_simplify (&result, simplify, compare)) {
1727 gst_caps_switch_structures (caps, simplify, result, i);
1730 gst_caps_remove_structure (caps, i);
1742 /* gst_caps_do_simplify (caps); */
1749 * gst_caps_to_string:
1752 * Converts @caps to a string representation. This string representation
1753 * can be converted back to a #GstCaps by gst_caps_from_string().
1755 * For debugging purposes its easier to do something like this:
1757 * GST_LOG ("caps are %" GST_PTR_FORMAT, caps);
1759 * This prints the caps in human readble form.
1761 * Returns: (transfer full): a newly allocated string representing @caps.
1764 gst_caps_to_string (const GstCaps * caps)
1766 guint i, slen, clen;
1769 /* NOTE: This function is potentially called by the debug system,
1770 * so any calls to gst_log() (and GST_DEBUG(), GST_LOG(), etc.)
1771 * should be careful to avoid recursion. This includes any functions
1772 * called by gst_caps_to_string. In particular, calls should
1773 * not use the GST_PTR_FORMAT extension. */
1776 return g_strdup ("NULL");
1778 if (CAPS_IS_ANY (caps)) {
1779 return g_strdup ("ANY");
1781 if (CAPS_IS_EMPTY_SIMPLE (caps)) {
1782 return g_strdup ("EMPTY");
1785 /* estimate a rough string length to avoid unnecessary reallocs in GString */
1787 clen = caps->structs->len;
1788 for (i = 0; i < clen; i++) {
1790 STRUCTURE_ESTIMATED_STRING_LEN (gst_caps_get_structure_unchecked (caps,
1794 s = g_string_sized_new (slen);
1795 for (i = 0; i < clen; i++) {
1796 GstStructure *structure;
1799 /* ';' is now added by gst_structure_to_string */
1800 g_string_append_c (s, ' ');
1803 structure = gst_caps_get_structure_unchecked (caps, i);
1804 priv_gst_structure_append_to_gstring (structure, s);
1806 if (s->len && s->str[s->len - 1] == ';') {
1807 /* remove latest ';' */
1808 s->str[--s->len] = '\0';
1810 return g_string_free (s, FALSE);
1814 gst_caps_from_string_inplace (GstCaps * caps, const gchar * string)
1816 GstStructure *structure;
1819 if (strcmp ("ANY", string) == 0) {
1820 GST_CAPS_FLAGS (caps) = GST_CAPS_FLAGS_ANY;
1823 if (strcmp ("EMPTY", string) == 0) {
1827 structure = gst_structure_from_string (string, &s);
1828 if (structure == NULL) {
1831 gst_caps_append_structure_unchecked (caps, structure);
1835 while (g_ascii_isspace (*s))
1840 structure = gst_structure_from_string (s, &s);
1841 if (structure == NULL) {
1844 gst_caps_append_structure_unchecked (caps, structure);
1852 * gst_caps_from_string:
1853 * @string: a string to convert to #GstCaps
1855 * Converts @caps from a string representation.
1857 * Returns: (transfer full): a newly allocated #GstCaps
1860 gst_caps_from_string (const gchar * string)
1864 g_return_val_if_fail (string, FALSE);
1866 caps = gst_caps_new_empty ();
1867 if (gst_caps_from_string_inplace (caps, string)) {
1870 gst_caps_unref (caps);
1876 gst_caps_transform_to_string (const GValue * src_value, GValue * dest_value)
1878 g_return_if_fail (G_IS_VALUE (src_value));
1879 g_return_if_fail (G_IS_VALUE (dest_value));
1880 g_return_if_fail (G_VALUE_HOLDS (src_value, GST_TYPE_CAPS));
1881 g_return_if_fail (G_VALUE_HOLDS (dest_value, G_TYPE_STRING)
1882 || G_VALUE_HOLDS (dest_value, G_TYPE_POINTER));
1884 dest_value->data[0].v_pointer =
1885 gst_caps_to_string (src_value->data[0].v_pointer);