2 * Copyright (C) 2010 Wim Taymans <wim.taymans@gmail.com>
4 * gstbufferpool.c: GstBufferPool baseclass
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Library General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Library General Public License for more details.
16 * You should have received a copy of the GNU Library General Public
17 * License along with this library; if not, write to the
18 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 * Boston, MA 02111-1307, USA.
23 * SECTION:gstbufferpool
24 * @short_description: Pool for buffers
25 * @see_also: #GstBuffer
29 /* FIXME 0.11: suppress warnings for deprecated API such as GStaticRecMutex
30 * with newer GLib versions (>= 2.31.0) */
31 #define GLIB_DISABLE_DEPRECATION_WARNINGS
32 #include "gst_private.h"
33 #include "glib-compat-private.h"
39 #include <sys/types.h>
44 #include "gstbufferpool.h"
46 GST_DEBUG_CATEGORY_STATIC (gst_buffer_pool_debug);
47 #define GST_CAT_DEFAULT gst_buffer_pool_debug
49 #define GST_BUFFER_POOL_GET_PRIVATE(obj) \
50 (G_TYPE_INSTANCE_GET_PRIVATE ((obj), GST_TYPE_BUFFER_POOL, GstBufferPoolPrivate))
52 #define GST_BUFFER_POOL_LOCK(pool) (g_static_rec_mutex_lock(&pool->priv->rec_lock))
53 #define GST_BUFFER_POOL_UNLOCK(pool) (g_static_rec_mutex_unlock(&pool->priv->rec_lock))
55 struct _GstBufferPoolPrivate
57 GStaticRecMutex rec_lock;
71 static void gst_buffer_pool_finalize (GObject * object);
73 G_DEFINE_TYPE (GstBufferPool, gst_buffer_pool, GST_TYPE_OBJECT);
75 static gboolean default_start (GstBufferPool * pool);
76 static gboolean default_stop (GstBufferPool * pool);
77 static gboolean default_set_config (GstBufferPool * pool,
78 GstStructure * config);
79 static GstFlowReturn default_alloc_buffer (GstBufferPool * pool,
80 GstBuffer ** buffer, GstBufferPoolParams * params);
81 static GstFlowReturn default_acquire_buffer (GstBufferPool * pool,
82 GstBuffer ** buffer, GstBufferPoolParams * params);
83 static void default_reset_buffer (GstBufferPool * pool, GstBuffer * buffer,
84 GstBufferPoolParams * params);
85 static void default_free_buffer (GstBufferPool * pool, GstBuffer * buffer);
86 static void default_release_buffer (GstBufferPool * pool, GstBuffer * buffer);
89 gst_buffer_pool_class_init (GstBufferPoolClass * klass)
91 GObjectClass *gobject_class = (GObjectClass *) klass;
93 g_type_class_add_private (klass, sizeof (GstBufferPoolPrivate));
95 gobject_class->finalize = gst_buffer_pool_finalize;
97 klass->start = default_start;
98 klass->stop = default_stop;
99 klass->set_config = default_set_config;
100 klass->acquire_buffer = default_acquire_buffer;
101 klass->reset_buffer = default_reset_buffer;
102 klass->alloc_buffer = default_alloc_buffer;
103 klass->release_buffer = default_release_buffer;
104 klass->free_buffer = default_free_buffer;
106 GST_DEBUG_CATEGORY_INIT (gst_buffer_pool_debug, "bufferpool", 0,
111 gst_buffer_pool_init (GstBufferPool * pool)
113 pool->priv = GST_BUFFER_POOL_GET_PRIVATE (pool);
115 g_static_rec_mutex_init (&pool->priv->rec_lock);
117 pool->poll = gst_poll_new_timer ();
118 pool->queue = gst_atomic_queue_new (10);
119 pool->flushing = TRUE;
120 pool->active = FALSE;
121 pool->configured = FALSE;
122 pool->started = FALSE;
123 pool->config = gst_structure_new_id_empty (GST_QUARK (BUFFER_POOL_CONFIG));
124 gst_buffer_pool_config_set (pool->config, NULL, 0, 0, 0, 0, 0);
125 gst_poll_write_control (pool->poll);
127 GST_DEBUG_OBJECT (pool, "created");
131 gst_buffer_pool_finalize (GObject * object)
135 pool = GST_BUFFER_POOL_CAST (object);
137 GST_DEBUG_OBJECT (pool, "finalize");
139 gst_buffer_pool_set_active (pool, FALSE);
140 gst_atomic_queue_unref (pool->queue);
141 gst_poll_free (pool->poll);
142 gst_structure_free (pool->config);
143 g_static_rec_mutex_free (&pool->priv->rec_lock);
145 G_OBJECT_CLASS (gst_buffer_pool_parent_class)->finalize (object);
149 * gst_buffer_pool_new:
151 * Creates a new #GstBufferPool instance.
153 * Returns: (transfer full): a new #GstBufferPool instance
156 gst_buffer_pool_new (void)
158 GstBufferPool *result;
160 result = g_object_newv (GST_TYPE_BUFFER_POOL, 0, NULL);
161 GST_DEBUG_OBJECT (result, "created new buffer pool");
167 default_alloc_buffer (GstBufferPool * pool, GstBuffer ** buffer,
168 GstBufferPoolParams * params)
170 GstBufferPoolPrivate *priv = pool->priv;
173 *buffer = gst_buffer_new ();
175 mem = gst_allocator_alloc (NULL, priv->size + priv->prefix, priv->align);
176 gst_memory_resize (mem, priv->prefix, priv->size);
177 gst_buffer_take_memory (*buffer, -1, mem);
183 mark_meta_pooled (GstBuffer * buffer, GstMeta ** meta, gpointer user_data)
185 GST_META_FLAG_SET (*meta, GST_META_FLAG_POOLED);
190 /* the default implementation for preallocating the buffers
193 default_start (GstBufferPool * pool)
196 GstBufferPoolPrivate *priv = pool->priv;
197 GstBufferPoolClass *pclass;
199 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
201 /* no alloc function, error */
202 if (G_UNLIKELY (pclass->alloc_buffer == NULL))
205 /* we need to prealloc buffers */
206 for (i = 0; i < priv->min_buffers; i++) {
209 if (pclass->alloc_buffer (pool, &buffer, NULL) != GST_FLOW_OK)
212 gst_buffer_foreach_meta (buffer, mark_meta_pooled, pool);
213 GST_LOG_OBJECT (pool, "prealloced buffer %d: %p", i, buffer);
214 /* release to the queue, we call the vmethod directly, we don't need to do
215 * the other refcount handling right now. */
216 if (G_LIKELY (pclass->release_buffer))
217 pclass->release_buffer (pool, buffer);
224 GST_WARNING_OBJECT (pool, "no alloc function");
229 GST_WARNING_OBJECT (pool, "alloc function failed");
234 /* must be called with the lock */
236 do_start (GstBufferPool * pool)
238 if (!pool->started) {
239 GstBufferPoolClass *pclass;
241 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
243 GST_LOG_OBJECT (pool, "starting");
244 /* start the pool, subclasses should allocate buffers and put them
246 if (G_LIKELY (pclass->start)) {
247 if (!pclass->start (pool))
250 pool->started = TRUE;
257 default_free_buffer (GstBufferPool * pool, GstBuffer * buffer)
259 gst_buffer_unref (buffer);
262 /* must be called with the lock */
264 default_stop (GstBufferPool * pool)
267 GstBufferPoolClass *pclass;
269 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
272 while ((buffer = gst_atomic_queue_pop (pool->queue))) {
273 GST_LOG_OBJECT (pool, "freeing %p", buffer);
274 gst_poll_read_control (pool->poll);
276 if (G_LIKELY (pclass->free_buffer))
277 pclass->free_buffer (pool, buffer);
282 /* must be called with the lock */
284 do_stop (GstBufferPool * pool)
287 GstBufferPoolClass *pclass;
289 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
291 GST_LOG_OBJECT (pool, "stopping");
292 if (G_LIKELY (pclass->stop)) {
293 if (!pclass->stop (pool))
296 pool->started = FALSE;
302 * gst_buffer_pool_set_active:
303 * @pool: a #GstBufferPool
304 * @active: the new active state
306 * Control the active state of @pool. When the pool is active, new calls to
307 * gst_buffer_pool_acquire_buffer() will return with GST_FLOW_WRONG_STATE.
309 * Activating the bufferpool will preallocate all resources in the pool based on
310 * the configuration of the pool.
312 * Deactivating will free the resources again when there are no outstanding
313 * buffers. When there are outstanding buffers, they will be freed as soon as
314 * they are all returned to the pool.
316 * Returns: %FALSE when the pool was not configured or when preallocation of the
320 gst_buffer_pool_set_active (GstBufferPool * pool, gboolean active)
324 g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), FALSE);
326 GST_LOG_OBJECT (pool, "active %d", active);
328 GST_BUFFER_POOL_LOCK (pool);
329 /* just return if we are already in the right state */
330 if (pool->active == active)
333 /* we need to be configured */
334 if (!pool->configured)
338 if (!do_start (pool))
341 /* unset the flushing state now */
342 gst_poll_read_control (pool->poll);
343 g_atomic_int_set (&pool->flushing, FALSE);
347 /* set to flushing first */
348 g_atomic_int_set (&pool->flushing, TRUE);
349 gst_poll_write_control (pool->poll);
351 /* when all buffers are in the pool, free them. Else they will be
352 * freed when they are released */
353 outstanding = g_atomic_int_get (&pool->outstanding);
354 GST_LOG_OBJECT (pool, "outstanding buffers %d", outstanding);
355 if (outstanding == 0) {
360 pool->active = active;
361 GST_BUFFER_POOL_UNLOCK (pool);
367 GST_DEBUG_OBJECT (pool, "pool was in the right state");
368 GST_BUFFER_POOL_UNLOCK (pool);
373 GST_ERROR_OBJECT (pool, "pool was not configured");
374 GST_BUFFER_POOL_UNLOCK (pool);
379 GST_ERROR_OBJECT (pool, "start failed");
380 GST_BUFFER_POOL_UNLOCK (pool);
385 GST_WARNING_OBJECT (pool, "stop failed");
386 GST_BUFFER_POOL_UNLOCK (pool);
392 * gst_buffer_pool_is_active:
393 * @pool: a #GstBufferPool
395 * Check if @pool is active. A pool can be activated with the
396 * gst_buffer_pool_set_active() call.
398 * Returns: %TRUE when the pool is active.
401 gst_buffer_pool_is_active (GstBufferPool * pool)
405 GST_BUFFER_POOL_LOCK (pool);
407 GST_BUFFER_POOL_UNLOCK (pool);
413 default_set_config (GstBufferPool * pool, GstStructure * config)
415 GstBufferPoolPrivate *priv = pool->priv;
417 guint size, min_buffers, max_buffers;
420 /* parse the config and keep around */
421 if (!gst_buffer_pool_config_get (config, &caps, &size, &min_buffers,
422 &max_buffers, &prefix, &align))
425 GST_DEBUG_OBJECT (pool, "config %" GST_PTR_FORMAT, config);
428 priv->min_buffers = min_buffers;
429 priv->max_buffers = max_buffers;
430 priv->prefix = prefix;
437 GST_WARNING_OBJECT (pool, "invalid config %" GST_PTR_FORMAT, config);
443 * gst_buffer_pool_set_config:
444 * @pool: a #GstBufferPool
445 * @config: (transfer full): a #GstStructure
447 * Set the configuration of the pool. The pool must be inactive and all buffers
448 * allocated form this pool must be returned or else this function will do
449 * nothing and return FALSE.
451 * @config is a #GstStructure that contains the configuration parameters for
452 * the pool. A default and mandatory set of parameters can be configured with
453 * gst_buffer_pool_config_set(). This function takes ownership of @config.
455 * Returns: TRUE when the configuration could be set.
458 gst_buffer_pool_set_config (GstBufferPool * pool, GstStructure * config)
461 GstBufferPoolClass *pclass;
463 g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), FALSE);
464 g_return_val_if_fail (config != NULL, FALSE);
466 GST_BUFFER_POOL_LOCK (pool);
467 /* can't change the settings when active */
471 /* we can't change when outstanding buffers */
472 if (g_atomic_int_get (&pool->outstanding) != 0)
473 goto have_outstanding;
475 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
477 /* set the new config */
478 if (G_LIKELY (pclass->set_config))
479 result = pclass->set_config (pool, config);
485 gst_structure_free (pool->config);
486 pool->config = config;
488 /* now we are configured */
489 pool->configured = TRUE;
491 GST_BUFFER_POOL_UNLOCK (pool);
498 GST_WARNING_OBJECT (pool, "can't change config, we are active");
499 GST_BUFFER_POOL_UNLOCK (pool);
504 GST_WARNING_OBJECT (pool, "can't change config, have outstanding buffers");
505 GST_BUFFER_POOL_UNLOCK (pool);
511 * gst_buffer_pool_get_config:
512 * @pool: a #GstBufferPool
514 * Get a copy of the current configuration of the pool. This configuration
515 * can either be modified and used for the gst_buffer_pool_set_config() call
516 * or it must be freed after usage.
518 * Returns: (transfer full): a copy of the current configuration of @pool. use
519 * gst_structure_free() after usage or gst_buffer_pool_set_config().
522 gst_buffer_pool_get_config (GstBufferPool * pool)
524 GstStructure *result;
526 g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), NULL);
528 GST_BUFFER_POOL_UNLOCK (pool);
529 result = gst_structure_copy (pool->config);
530 GST_BUFFER_POOL_UNLOCK (pool);
535 static const gchar *empty_option[] = { NULL };
538 * gst_buffer_pool_get_options:
539 * @pool: a #GstBufferPool
541 * Get a NULL terminated array of string with supported bufferpool options for
542 * @pool. An option would typically be enabled with
543 * gst_buffer_pool_config_add_option().
545 * Returns: (array zero-terminated=1) (transfer none): a NULL terminated array of strings.
548 gst_buffer_pool_get_options (GstBufferPool * pool)
550 GstBufferPoolClass *pclass;
551 const gchar **result;
553 g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), NULL);
555 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
557 if (G_LIKELY (pclass->get_options)) {
558 if ((result = pclass->get_options (pool)) == NULL)
561 result = empty_option;
568 g_warning ("bufferpool subclass returned NULL options");
574 * gst_buffer_pool_has_option:
575 * @pool: a #GstBufferPool
578 * Check if the bufferpool supports @option.
580 * Returns: a NULL terminated array of strings.
583 gst_buffer_pool_has_option (GstBufferPool * pool, const gchar * option)
586 const gchar **options;
588 g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), FALSE);
589 g_return_val_if_fail (option != NULL, FALSE);
591 options = gst_buffer_pool_get_options (pool);
593 for (i = 0; options[i]; i++) {
594 if (g_str_equal (options[i], option))
601 * gst_buffer_pool_config_set:
602 * @config: a #GstBufferPool configuration
603 * @caps: caps for the buffers
604 * @size: the size of each buffer, not including prefix
605 * @min_buffers: the minimum amount of buffers to allocate.
606 * @max_buffers: the maximum amount of buffers to allocate or 0 for unlimited.
607 * @prefix: prefix each buffer with this many bytes
608 * @align: alignment of the buffer data.
610 * Configure @config with the given parameters.
613 gst_buffer_pool_config_set (GstStructure * config, const GstCaps * caps,
614 guint size, guint min_buffers, guint max_buffers, guint prefix, guint align)
616 g_return_if_fail (config != NULL);
618 gst_structure_id_set (config,
619 GST_QUARK (CAPS), GST_TYPE_CAPS, caps,
620 GST_QUARK (SIZE), G_TYPE_UINT, size,
621 GST_QUARK (MIN_BUFFERS), G_TYPE_UINT, min_buffers,
622 GST_QUARK (MAX_BUFFERS), G_TYPE_UINT, max_buffers,
623 GST_QUARK (PREFIX), G_TYPE_UINT, prefix,
624 GST_QUARK (ALIGN), G_TYPE_UINT, align, NULL);
628 * gst_buffer_pool_config_add_option:
629 * @config: a #GstBufferPool configuration
630 * @option: an option to add
632 * Enabled the option in @config. This will instruct the @bufferpool to enable
633 * the specified option on the buffers that it allocates.
635 * The supported options by @pool can be retrieved with gst_buffer_pool_get_options().
638 gst_buffer_pool_config_add_option (GstStructure * config, const gchar * option)
642 GValue option_value = { 0 };
645 g_return_if_fail (config != NULL);
647 value = gst_structure_id_get_value (config, GST_QUARK (OPTIONS));
649 array = (GValueArray *) g_value_get_boxed (value);
651 GValue new_array_val = { 0, };
653 array = g_value_array_new (0);
655 g_value_init (&new_array_val, G_TYPE_VALUE_ARRAY);
656 g_value_take_boxed (&new_array_val, array);
658 gst_structure_id_take_value (config, GST_QUARK (OPTIONS), &new_array_val);
660 for (i = 0; i < array->n_values; i++) {
661 value = g_value_array_get_nth (array, i);
662 if (g_str_equal (option, g_value_get_string (value)))
665 g_value_init (&option_value, G_TYPE_STRING);
666 g_value_set_string (&option_value, option);
667 g_value_array_append (array, &option_value);
668 g_value_unset (&option_value);
672 * gst_buffer_pool_config_n_options:
673 * @config: a #GstBufferPool configuration
675 * Retrieve the number of values currently stored in the
676 * options array of the @config structure.
678 * Returns: the options array size as a #guint.
681 gst_buffer_pool_config_n_options (GstStructure * config)
687 g_return_val_if_fail (config != NULL, 0);
689 value = gst_structure_id_get_value (config, GST_QUARK (OPTIONS));
691 array = (GValueArray *) g_value_get_boxed (value);
692 size = array->n_values;
698 * gst_buffer_pool_config_get_option:
699 * @config: a #GstBufferPool configuration
700 * @index: position in the option array to read
702 * Parse an available @config and get the option
703 * at @index of the options API array.
705 * Returns: a #gchar of the option at @index.
708 gst_buffer_pool_config_get_option (GstStructure * config, guint index)
711 const gchar *ret = NULL;
713 g_return_val_if_fail (config != NULL, 0);
715 value = gst_structure_id_get_value (config, GST_QUARK (OPTIONS));
718 GValue *option_value;
720 array = (GValueArray *) g_value_get_boxed (value);
721 option_value = g_value_array_get_nth (array, index);
724 ret = g_value_get_string (option_value);
730 * gst_buffer_pool_config_has_option:
731 * @config: a #GstBufferPool configuration
734 * Check if @config contains @option
736 * Returns: TRUE if the options array contains @option.
739 gst_buffer_pool_config_has_option (GstStructure * config, const gchar * option)
743 g_return_val_if_fail (config != NULL, 0);
745 value = gst_structure_id_get_value (config, GST_QUARK (OPTIONS));
748 GValue *option_value;
751 array = (GValueArray *) g_value_get_boxed (value);
752 for (i = 0; i < array->n_values; i++) {
753 option_value = g_value_array_get_nth (array, i);
754 if (g_str_equal (option, g_value_get_string (option_value)))
762 * gst_buffer_pool_config_get:
763 * @config: (transfer none): a #GstBufferPool configuration
764 * @caps: (out): the caps of buffers
765 * @size: (out): the size of each buffer, not including prefix
766 * @min_buffers: (out): the minimum amount of buffers to allocate.
767 * @max_buffers: (out): the maximum amount of buffers to allocate or 0 for unlimited.
768 * @prefix: (out): prefix each buffer with this many bytes
769 * @align: (out): alignment of the buffer data.
771 * Get the configuration values from @config.
774 gst_buffer_pool_config_get (GstStructure * config, const GstCaps ** caps,
775 guint * size, guint * min_buffers, guint * max_buffers, guint * prefix,
778 g_return_val_if_fail (config != NULL, FALSE);
780 return gst_structure_id_get (config,
781 GST_QUARK (CAPS), GST_TYPE_CAPS, caps,
782 GST_QUARK (SIZE), G_TYPE_UINT, size,
783 GST_QUARK (MIN_BUFFERS), G_TYPE_UINT, min_buffers,
784 GST_QUARK (MAX_BUFFERS), G_TYPE_UINT, max_buffers,
785 GST_QUARK (PREFIX), G_TYPE_UINT, prefix,
786 GST_QUARK (ALIGN), G_TYPE_UINT, align, NULL);
790 default_acquire_buffer (GstBufferPool * pool, GstBuffer ** buffer,
791 GstBufferPoolParams * params)
793 GstFlowReturn result;
794 GstBufferPoolClass *pclass;
795 GstBufferPoolPrivate *priv = pool->priv;
797 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
800 if (G_UNLIKELY (g_atomic_int_get (&pool->flushing)))
803 /* try to get a buffer from the queue */
804 *buffer = gst_atomic_queue_pop (pool->queue);
805 if (G_LIKELY (*buffer)) {
806 gst_poll_read_control (pool->poll);
807 result = GST_FLOW_OK;
808 GST_LOG_OBJECT (pool, "acquired buffer %p", *buffer);
813 if (priv->max_buffers == 0) {
814 /* no max_buffers, we allocate some more */
815 if (G_LIKELY (pclass->alloc_buffer)) {
816 result = pclass->alloc_buffer (pool, buffer, params);
817 if (result == GST_FLOW_OK && *buffer)
818 gst_buffer_foreach_meta (*buffer, mark_meta_pooled, pool);
820 result = GST_FLOW_ERROR;
822 result = GST_FLOW_NOT_SUPPORTED;
823 GST_LOG_OBJECT (pool, "alloc buffer %p", *buffer);
827 /* check if we need to wait */
828 if (params && (params->flags & GST_BUFFER_POOL_FLAG_DONTWAIT)) {
829 GST_LOG_OBJECT (pool, "no more buffers");
830 result = GST_FLOW_EOS;
835 GST_LOG_OBJECT (pool, "waiting for free buffers");
836 gst_poll_wait (pool->poll, GST_CLOCK_TIME_NONE);
844 GST_DEBUG_OBJECT (pool, "we are flushing");
845 return GST_FLOW_WRONG_STATE;
850 dec_outstanding (GstBufferPool * pool)
852 if (g_atomic_int_dec_and_test (&pool->outstanding)) {
853 /* all buffers are returned to the pool, see if we need to free them */
854 if (g_atomic_int_get (&pool->flushing)) {
855 /* take the lock so that set_active is not run concurrently */
856 GST_BUFFER_POOL_LOCK (pool);
857 /* recheck the flushing state in the lock, the pool could have been
858 * set to active again */
859 if (g_atomic_int_get (&pool->flushing))
862 GST_BUFFER_POOL_UNLOCK (pool);
868 remove_meta_unpooled (GstBuffer * buffer, GstMeta ** meta, gpointer user_data)
870 if (!GST_META_FLAG_IS_SET (*meta, GST_META_FLAG_POOLED))
876 default_reset_buffer (GstBufferPool * pool, GstBuffer * buffer,
877 GstBufferPoolParams * params)
879 GST_BUFFER_FLAGS (buffer) = 0;
881 GST_BUFFER_PTS (buffer) = GST_CLOCK_TIME_NONE;
882 GST_BUFFER_DTS (buffer) = GST_CLOCK_TIME_NONE;
883 GST_BUFFER_DURATION (buffer) = GST_CLOCK_TIME_NONE;
884 GST_BUFFER_OFFSET (buffer) = GST_BUFFER_OFFSET_NONE;
885 GST_BUFFER_OFFSET_END (buffer) = GST_BUFFER_OFFSET_NONE;
887 /* remove all metadata without the POOLED flag */
888 gst_buffer_foreach_meta (buffer, remove_meta_unpooled, pool);
892 * gst_buffer_pool_acquire_buffer:
893 * @pool: a #GstBufferPool
894 * @buffer: (out): a location for a #GstBuffer
895 * @params: (transfer none) (allow-none) parameters.
897 * Acquire a buffer from @pool. @buffer should point to a memory location that
898 * can hold a pointer to the new buffer.
900 * @params can be NULL or contain optional parameters to influence the allocation.
902 * Returns: a #GstFlowReturn such as GST_FLOW_WRONG_STATE when the pool is
906 gst_buffer_pool_acquire_buffer (GstBufferPool * pool, GstBuffer ** buffer,
907 GstBufferPoolParams * params)
909 GstBufferPoolClass *pclass;
910 GstFlowReturn result;
912 g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), GST_FLOW_ERROR);
913 g_return_val_if_fail (buffer != NULL, GST_FLOW_ERROR);
915 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
917 /* assume we'll have one more outstanding buffer we need to do that so
918 * that concurrent set_active doesn't clear the buffers */
919 g_atomic_int_inc (&pool->outstanding);
921 if (G_LIKELY (pclass->acquire_buffer))
922 result = pclass->acquire_buffer (pool, buffer, params);
924 result = GST_FLOW_NOT_SUPPORTED;
926 if (G_LIKELY (result == GST_FLOW_OK)) {
927 /* all buffers from the pool point to the pool and have the refcount of the
928 * pool incremented */
929 (*buffer)->pool = gst_object_ref (pool);
930 /* now reset the buffer when needed */
931 if (G_LIKELY (pclass->reset_buffer))
932 pclass->reset_buffer (pool, *buffer, params);
934 dec_outstanding (pool);
941 default_release_buffer (GstBufferPool * pool, GstBuffer * buffer)
943 /* keep it around in our queue */
944 GST_LOG_OBJECT (pool, "released buffer %p", buffer);
945 gst_atomic_queue_push (pool->queue, buffer);
946 gst_poll_write_control (pool->poll);
950 * gst_buffer_pool_release_buffer:
951 * @pool: a #GstBufferPool
952 * @buffer: (transfer none): a #GstBuffer
954 * Release @buffer to @pool. @buffer should have previously been allocated from
955 * @pool with gst_buffer_pool_acquire_buffer().
957 * This function is usually called automatically when the last ref on @buffer
961 gst_buffer_pool_release_buffer (GstBufferPool * pool, GstBuffer * buffer)
963 GstBufferPoolClass *pclass;
965 g_return_if_fail (GST_IS_BUFFER_POOL (pool));
966 g_return_if_fail (buffer != NULL);
968 /* check that the buffer is ours, all buffers returned to the pool have the
969 * pool member set to NULL and the pool refcount decreased */
970 if (!G_ATOMIC_POINTER_COMPARE_AND_EXCHANGE (&buffer->pool, pool, NULL))
973 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
975 if (G_LIKELY (pclass->release_buffer))
976 pclass->release_buffer (pool, buffer);
978 dec_outstanding (pool);
980 /* decrease the refcount that the buffer had to us */
981 gst_object_unref (pool);