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 #include "gst_private.h"
30 #include "glib-compat-private.h"
36 #include <sys/types.h>
38 #include "gstatomicqueue.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_rec_mutex_lock(&pool->priv->rec_lock))
53 #define GST_BUFFER_POOL_UNLOCK(pool) (g_rec_mutex_unlock(&pool->priv->rec_lock))
55 struct _GstBufferPoolPrivate
57 GstAtomicQueue *queue;
82 static void gst_buffer_pool_finalize (GObject * object);
84 G_DEFINE_TYPE (GstBufferPool, gst_buffer_pool, GST_TYPE_OBJECT);
86 static gboolean default_start (GstBufferPool * pool);
87 static gboolean default_stop (GstBufferPool * pool);
88 static gboolean default_set_config (GstBufferPool * pool,
89 GstStructure * config);
90 static GstFlowReturn default_alloc_buffer (GstBufferPool * pool,
91 GstBuffer ** buffer, GstBufferPoolParams * params);
92 static GstFlowReturn default_acquire_buffer (GstBufferPool * pool,
93 GstBuffer ** buffer, GstBufferPoolParams * params);
94 static void default_reset_buffer (GstBufferPool * pool, GstBuffer * buffer,
95 GstBufferPoolParams * params);
96 static void default_free_buffer (GstBufferPool * pool, GstBuffer * buffer);
97 static void default_release_buffer (GstBufferPool * pool, GstBuffer * buffer);
100 gst_buffer_pool_class_init (GstBufferPoolClass * klass)
102 GObjectClass *gobject_class = (GObjectClass *) klass;
104 g_type_class_add_private (klass, sizeof (GstBufferPoolPrivate));
106 gobject_class->finalize = gst_buffer_pool_finalize;
108 klass->start = default_start;
109 klass->stop = default_stop;
110 klass->set_config = default_set_config;
111 klass->acquire_buffer = default_acquire_buffer;
112 klass->reset_buffer = default_reset_buffer;
113 klass->alloc_buffer = default_alloc_buffer;
114 klass->release_buffer = default_release_buffer;
115 klass->free_buffer = default_free_buffer;
117 GST_DEBUG_CATEGORY_INIT (gst_buffer_pool_debug, "bufferpool", 0,
122 gst_buffer_pool_init (GstBufferPool * pool)
124 pool->priv = GST_BUFFER_POOL_GET_PRIVATE (pool);
126 g_rec_mutex_init (&pool->priv->rec_lock);
128 pool->priv->poll = gst_poll_new_timer ();
129 pool->priv->queue = gst_atomic_queue_new (10);
131 pool->priv->active = FALSE;
132 pool->priv->configured = FALSE;
133 pool->priv->started = FALSE;
135 gst_structure_new_id_empty (GST_QUARK (BUFFER_POOL_CONFIG));
136 gst_buffer_pool_config_set (pool->priv->config, NULL, 0, 0, 0, 0, 0);
137 gst_poll_write_control (pool->priv->poll);
139 GST_DEBUG_OBJECT (pool, "created");
143 gst_buffer_pool_finalize (GObject * object)
147 pool = GST_BUFFER_POOL_CAST (object);
149 GST_DEBUG_OBJECT (pool, "finalize");
151 gst_buffer_pool_set_active (pool, FALSE);
152 gst_atomic_queue_unref (pool->priv->queue);
153 gst_poll_free (pool->priv->poll);
154 gst_structure_free (pool->priv->config);
155 g_rec_mutex_clear (&pool->priv->rec_lock);
157 G_OBJECT_CLASS (gst_buffer_pool_parent_class)->finalize (object);
161 * gst_buffer_pool_new:
163 * Creates a new #GstBufferPool instance.
165 * Returns: (transfer full): a new #GstBufferPool instance
168 gst_buffer_pool_new (void)
170 GstBufferPool *result;
172 result = g_object_newv (GST_TYPE_BUFFER_POOL, 0, NULL);
173 GST_DEBUG_OBJECT (result, "created new buffer pool");
179 default_alloc_buffer (GstBufferPool * pool, GstBuffer ** buffer,
180 GstBufferPoolParams * params)
182 GstBufferPoolPrivate *priv = pool->priv;
185 *buffer = gst_buffer_new ();
187 mem = gst_allocator_alloc (NULL, priv->size + priv->prefix, priv->align);
188 gst_memory_resize (mem, priv->prefix, priv->size);
189 gst_buffer_take_memory (*buffer, -1, mem);
195 mark_meta_pooled (GstBuffer * buffer, GstMeta ** meta, gpointer user_data)
197 GST_META_FLAG_SET (*meta, GST_META_FLAG_POOLED);
202 /* the default implementation for preallocating the buffers
205 default_start (GstBufferPool * pool)
208 GstBufferPoolPrivate *priv = pool->priv;
209 GstBufferPoolClass *pclass;
211 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
213 /* no alloc function, error */
214 if (G_UNLIKELY (pclass->alloc_buffer == NULL))
217 /* we need to prealloc buffers */
218 for (i = 0; i < priv->min_buffers; i++) {
221 if (pclass->alloc_buffer (pool, &buffer, NULL) != GST_FLOW_OK)
224 gst_buffer_foreach_meta (buffer, mark_meta_pooled, pool);
225 GST_LOG_OBJECT (pool, "prealloced buffer %d: %p", i, buffer);
226 /* release to the queue, we call the vmethod directly, we don't need to do
227 * the other refcount handling right now. */
228 if (G_LIKELY (pclass->release_buffer))
229 pclass->release_buffer (pool, buffer);
236 GST_WARNING_OBJECT (pool, "no alloc function");
241 GST_WARNING_OBJECT (pool, "alloc function failed");
246 /* must be called with the lock */
248 do_start (GstBufferPool * pool)
250 if (!pool->priv->started) {
251 GstBufferPoolClass *pclass;
253 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
255 GST_LOG_OBJECT (pool, "starting");
256 /* start the pool, subclasses should allocate buffers and put them
258 if (G_LIKELY (pclass->start)) {
259 if (!pclass->start (pool))
262 pool->priv->started = TRUE;
269 default_free_buffer (GstBufferPool * pool, GstBuffer * buffer)
271 gst_buffer_unref (buffer);
274 /* must be called with the lock */
276 default_stop (GstBufferPool * pool)
279 GstBufferPoolClass *pclass;
281 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
284 while ((buffer = gst_atomic_queue_pop (pool->priv->queue))) {
285 GST_LOG_OBJECT (pool, "freeing %p", buffer);
286 gst_poll_read_control (pool->priv->poll);
288 if (G_LIKELY (pclass->free_buffer))
289 pclass->free_buffer (pool, buffer);
294 /* must be called with the lock */
296 do_stop (GstBufferPool * pool)
298 if (pool->priv->started) {
299 GstBufferPoolClass *pclass;
301 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
303 GST_LOG_OBJECT (pool, "stopping");
304 if (G_LIKELY (pclass->stop)) {
305 if (!pclass->stop (pool))
308 pool->priv->started = FALSE;
314 * gst_buffer_pool_set_active:
315 * @pool: a #GstBufferPool
316 * @active: the new active state
318 * Control the active state of @pool. When the pool is active, new calls to
319 * gst_buffer_pool_acquire_buffer() will return with GST_FLOW_FLUSHING.
321 * Activating the bufferpool will preallocate all resources in the pool based on
322 * the configuration of the pool.
324 * Deactivating will free the resources again when there are no outstanding
325 * buffers. When there are outstanding buffers, they will be freed as soon as
326 * they are all returned to the pool.
328 * Returns: %FALSE when the pool was not configured or when preallocation of the
332 gst_buffer_pool_set_active (GstBufferPool * pool, gboolean active)
336 g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), FALSE);
338 GST_LOG_OBJECT (pool, "active %d", active);
340 GST_BUFFER_POOL_LOCK (pool);
341 /* just return if we are already in the right state */
342 if (pool->priv->active == active)
345 /* we need to be configured */
346 if (!pool->priv->configured)
350 if (!do_start (pool))
353 /* unset the flushing state now */
354 gst_poll_read_control (pool->priv->poll);
355 g_atomic_int_set (&pool->flushing, 0);
359 /* set to flushing first */
360 g_atomic_int_set (&pool->flushing, 1);
361 gst_poll_write_control (pool->priv->poll);
363 /* when all buffers are in the pool, free them. Else they will be
364 * freed when they are released */
365 outstanding = g_atomic_int_get (&pool->priv->outstanding);
366 GST_LOG_OBJECT (pool, "outstanding buffers %d", outstanding);
367 if (outstanding == 0) {
372 pool->priv->active = active;
373 GST_BUFFER_POOL_UNLOCK (pool);
379 GST_DEBUG_OBJECT (pool, "pool was in the right state");
380 GST_BUFFER_POOL_UNLOCK (pool);
385 GST_ERROR_OBJECT (pool, "pool was not configured");
386 GST_BUFFER_POOL_UNLOCK (pool);
391 GST_ERROR_OBJECT (pool, "start failed");
392 GST_BUFFER_POOL_UNLOCK (pool);
397 GST_WARNING_OBJECT (pool, "stop failed");
398 GST_BUFFER_POOL_UNLOCK (pool);
404 * gst_buffer_pool_is_active:
405 * @pool: a #GstBufferPool
407 * Check if @pool is active. A pool can be activated with the
408 * gst_buffer_pool_set_active() call.
410 * Returns: %TRUE when the pool is active.
413 gst_buffer_pool_is_active (GstBufferPool * pool)
417 GST_BUFFER_POOL_LOCK (pool);
418 res = pool->priv->active;
419 GST_BUFFER_POOL_UNLOCK (pool);
425 default_set_config (GstBufferPool * pool, GstStructure * config)
427 GstBufferPoolPrivate *priv = pool->priv;
429 guint size, min_buffers, max_buffers;
432 /* parse the config and keep around */
433 if (!gst_buffer_pool_config_get (config, &caps, &size, &min_buffers,
434 &max_buffers, &prefix, &align))
437 GST_DEBUG_OBJECT (pool, "config %" GST_PTR_FORMAT, config);
440 priv->min_buffers = min_buffers;
441 priv->max_buffers = max_buffers;
442 priv->prefix = prefix;
449 GST_WARNING_OBJECT (pool, "invalid config %" GST_PTR_FORMAT, config);
455 * gst_buffer_pool_set_config:
456 * @pool: a #GstBufferPool
457 * @config: (transfer full): a #GstStructure
459 * Set the configuration of the pool. The pool must be inactive and all buffers
460 * allocated form this pool must be returned or else this function will do
461 * nothing and return FALSE.
463 * @config is a #GstStructure that contains the configuration parameters for
464 * the pool. A default and mandatory set of parameters can be configured with
465 * gst_buffer_pool_config_set(). This function takes ownership of @config.
467 * Returns: TRUE when the configuration could be set.
470 gst_buffer_pool_set_config (GstBufferPool * pool, GstStructure * config)
473 GstBufferPoolClass *pclass;
475 g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), FALSE);
476 g_return_val_if_fail (config != NULL, FALSE);
478 GST_BUFFER_POOL_LOCK (pool);
479 /* can't change the settings when active */
480 if (pool->priv->active)
483 /* we can't change when outstanding buffers */
484 if (g_atomic_int_get (&pool->priv->outstanding) != 0)
485 goto have_outstanding;
487 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
489 /* set the new config */
490 if (G_LIKELY (pclass->set_config))
491 result = pclass->set_config (pool, config);
496 if (pool->priv->config)
497 gst_structure_free (pool->priv->config);
498 pool->priv->config = config;
500 /* now we are configured */
501 pool->priv->configured = TRUE;
503 GST_BUFFER_POOL_UNLOCK (pool);
510 GST_WARNING_OBJECT (pool, "can't change config, we are active");
511 GST_BUFFER_POOL_UNLOCK (pool);
516 GST_WARNING_OBJECT (pool, "can't change config, have outstanding buffers");
517 GST_BUFFER_POOL_UNLOCK (pool);
523 * gst_buffer_pool_get_config:
524 * @pool: a #GstBufferPool
526 * Get a copy of the current configuration of the pool. This configuration
527 * can either be modified and used for the gst_buffer_pool_set_config() call
528 * or it must be freed after usage.
530 * Returns: (transfer full): a copy of the current configuration of @pool. use
531 * gst_structure_free() after usage or gst_buffer_pool_set_config().
534 gst_buffer_pool_get_config (GstBufferPool * pool)
536 GstStructure *result;
538 g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), NULL);
540 GST_BUFFER_POOL_UNLOCK (pool);
541 result = gst_structure_copy (pool->priv->config);
542 GST_BUFFER_POOL_UNLOCK (pool);
547 static const gchar *empty_option[] = { NULL };
550 * gst_buffer_pool_get_options:
551 * @pool: a #GstBufferPool
553 * Get a NULL terminated array of string with supported bufferpool options for
554 * @pool. An option would typically be enabled with
555 * gst_buffer_pool_config_add_option().
557 * Returns: (array zero-terminated=1) (transfer none): a NULL terminated array of strings.
560 gst_buffer_pool_get_options (GstBufferPool * pool)
562 GstBufferPoolClass *pclass;
563 const gchar **result;
565 g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), NULL);
567 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
569 if (G_LIKELY (pclass->get_options)) {
570 if ((result = pclass->get_options (pool)) == NULL)
573 result = empty_option;
580 g_warning ("bufferpool subclass returned NULL options");
586 * gst_buffer_pool_has_option:
587 * @pool: a #GstBufferPool
590 * Check if the bufferpool supports @option.
592 * Returns: a NULL terminated array of strings.
595 gst_buffer_pool_has_option (GstBufferPool * pool, const gchar * option)
598 const gchar **options;
600 g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), FALSE);
601 g_return_val_if_fail (option != NULL, FALSE);
603 options = gst_buffer_pool_get_options (pool);
605 for (i = 0; options[i]; i++) {
606 if (g_str_equal (options[i], option))
613 * gst_buffer_pool_config_set:
614 * @config: a #GstBufferPool configuration
615 * @caps: caps for the buffers
616 * @size: the size of each buffer, not including prefix
617 * @min_buffers: the minimum amount of buffers to allocate.
618 * @max_buffers: the maximum amount of buffers to allocate or 0 for unlimited.
619 * @prefix: prefix each buffer with this many bytes
620 * @align: alignment of the buffer data.
622 * Configure @config with the given parameters.
625 gst_buffer_pool_config_set (GstStructure * config, const GstCaps * caps,
626 guint size, guint min_buffers, guint max_buffers, guint prefix, guint align)
628 g_return_if_fail (config != NULL);
630 gst_structure_id_set (config,
631 GST_QUARK (CAPS), GST_TYPE_CAPS, caps,
632 GST_QUARK (SIZE), G_TYPE_UINT, size,
633 GST_QUARK (MIN_BUFFERS), G_TYPE_UINT, min_buffers,
634 GST_QUARK (MAX_BUFFERS), G_TYPE_UINT, max_buffers,
635 GST_QUARK (PREFIX), G_TYPE_UINT, prefix,
636 GST_QUARK (ALIGN), G_TYPE_UINT, align, NULL);
640 * gst_buffer_pool_config_add_option:
641 * @config: a #GstBufferPool configuration
642 * @option: an option to add
644 * Enabled the option in @config. This will instruct the @bufferpool to enable
645 * the specified option on the buffers that it allocates.
647 * The supported options by @pool can be retrieved with gst_buffer_pool_get_options().
650 gst_buffer_pool_config_add_option (GstStructure * config, const gchar * option)
653 GValue option_value = { 0, };
656 g_return_if_fail (config != NULL);
658 value = gst_structure_id_get_value (config, GST_QUARK (OPTIONS));
660 len = gst_value_array_get_size (value);
661 for (i = 0; i < len; ++i) {
662 const GValue *nth_val = gst_value_array_get_value (value, i);
664 if (g_str_equal (option, g_value_get_string (nth_val)))
668 GValue new_array_val = { 0, };
670 g_value_init (&new_array_val, GST_TYPE_ARRAY);
671 gst_structure_id_take_value (config, GST_QUARK (OPTIONS), &new_array_val);
672 value = gst_structure_id_get_value (config, GST_QUARK (OPTIONS));
674 g_value_init (&option_value, G_TYPE_STRING);
675 g_value_set_string (&option_value, option);
676 gst_value_array_append_value ((GValue *) value, &option_value);
677 g_value_unset (&option_value);
681 * gst_buffer_pool_config_n_options:
682 * @config: a #GstBufferPool configuration
684 * Retrieve the number of values currently stored in the
685 * options array of the @config structure.
687 * Returns: the options array size as a #guint.
690 gst_buffer_pool_config_n_options (GstStructure * config)
695 g_return_val_if_fail (config != NULL, 0);
697 value = gst_structure_id_get_value (config, GST_QUARK (OPTIONS));
699 size = gst_value_array_get_size (value);
705 * gst_buffer_pool_config_get_option:
706 * @config: a #GstBufferPool configuration
707 * @index: position in the option array to read
709 * Parse an available @config and get the option
710 * at @index of the options API array.
712 * Returns: a #gchar of the option at @index.
715 gst_buffer_pool_config_get_option (GstStructure * config, guint index)
718 const gchar *ret = NULL;
720 g_return_val_if_fail (config != NULL, 0);
722 value = gst_structure_id_get_value (config, GST_QUARK (OPTIONS));
724 const GValue *option_value;
726 option_value = gst_value_array_get_value (value, index);
728 ret = g_value_get_string (option_value);
734 * gst_buffer_pool_config_has_option:
735 * @config: a #GstBufferPool configuration
738 * Check if @config contains @option
740 * Returns: TRUE if the options array contains @option.
743 gst_buffer_pool_config_has_option (GstStructure * config, const gchar * option)
748 g_return_val_if_fail (config != NULL, 0);
750 value = gst_structure_id_get_value (config, GST_QUARK (OPTIONS));
752 len = gst_value_array_get_size (value);
753 for (i = 0; i < len; ++i) {
754 const GValue *nth_val = gst_value_array_get_value (value, i);
756 if (g_str_equal (option, g_value_get_string (nth_val)))
764 * gst_buffer_pool_config_get:
765 * @config: (transfer none): a #GstBufferPool configuration
766 * @caps: (out): the caps of buffers
767 * @size: (out): the size of each buffer, not including prefix
768 * @min_buffers: (out): the minimum amount of buffers to allocate.
769 * @max_buffers: (out): the maximum amount of buffers to allocate or 0 for unlimited.
770 * @prefix: (out): prefix each buffer with this many bytes
771 * @align: (out): alignment of the buffer data.
773 * Get the configuration values from @config.
776 gst_buffer_pool_config_get (GstStructure * config, const GstCaps ** caps,
777 guint * size, guint * min_buffers, guint * max_buffers, guint * prefix,
780 g_return_val_if_fail (config != NULL, FALSE);
782 return gst_structure_id_get (config,
783 GST_QUARK (CAPS), GST_TYPE_CAPS, caps,
784 GST_QUARK (SIZE), G_TYPE_UINT, size,
785 GST_QUARK (MIN_BUFFERS), G_TYPE_UINT, min_buffers,
786 GST_QUARK (MAX_BUFFERS), G_TYPE_UINT, max_buffers,
787 GST_QUARK (PREFIX), G_TYPE_UINT, prefix,
788 GST_QUARK (ALIGN), G_TYPE_UINT, align, NULL);
792 default_acquire_buffer (GstBufferPool * pool, GstBuffer ** buffer,
793 GstBufferPoolParams * params)
795 GstFlowReturn result;
796 GstBufferPoolClass *pclass;
797 GstBufferPoolPrivate *priv = pool->priv;
799 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
802 if (G_UNLIKELY (GST_BUFFER_POOL_IS_FLUSHING (pool)))
805 /* try to get a buffer from the queue */
806 *buffer = gst_atomic_queue_pop (pool->priv->queue);
807 if (G_LIKELY (*buffer)) {
808 gst_poll_read_control (pool->priv->poll);
809 result = GST_FLOW_OK;
810 GST_LOG_OBJECT (pool, "acquired buffer %p", *buffer);
815 if (priv->max_buffers == 0) {
816 /* no max_buffers, we allocate some more */
817 if (G_LIKELY (pclass->alloc_buffer)) {
818 result = pclass->alloc_buffer (pool, buffer, params);
819 if (result == GST_FLOW_OK && *buffer)
820 gst_buffer_foreach_meta (*buffer, mark_meta_pooled, pool);
822 result = GST_FLOW_ERROR;
824 result = GST_FLOW_NOT_SUPPORTED;
825 GST_LOG_OBJECT (pool, "alloc buffer %p", *buffer);
829 /* check if we need to wait */
830 if (params && (params->flags & GST_BUFFER_POOL_FLAG_DONTWAIT)) {
831 GST_LOG_OBJECT (pool, "no more buffers");
832 result = GST_FLOW_EOS;
837 GST_LOG_OBJECT (pool, "waiting for free buffers");
838 gst_poll_wait (pool->priv->poll, GST_CLOCK_TIME_NONE);
846 GST_DEBUG_OBJECT (pool, "we are flushing");
847 return GST_FLOW_FLUSHING;
852 dec_outstanding (GstBufferPool * pool)
854 if (g_atomic_int_dec_and_test (&pool->priv->outstanding)) {
855 /* all buffers are returned to the pool, see if we need to free them */
856 if (GST_BUFFER_POOL_IS_FLUSHING (pool)) {
857 /* take the lock so that set_active is not run concurrently */
858 GST_BUFFER_POOL_LOCK (pool);
859 /* recheck the flushing state in the lock, the pool could have been
860 * set to active again */
861 if (GST_BUFFER_POOL_IS_FLUSHING (pool))
864 GST_BUFFER_POOL_UNLOCK (pool);
870 remove_meta_unpooled (GstBuffer * buffer, GstMeta ** meta, gpointer user_data)
872 if (!GST_META_FLAG_IS_SET (*meta, GST_META_FLAG_POOLED))
878 default_reset_buffer (GstBufferPool * pool, GstBuffer * buffer,
879 GstBufferPoolParams * params)
881 GST_BUFFER_FLAGS (buffer) = 0;
883 GST_BUFFER_PTS (buffer) = GST_CLOCK_TIME_NONE;
884 GST_BUFFER_DTS (buffer) = GST_CLOCK_TIME_NONE;
885 GST_BUFFER_DURATION (buffer) = GST_CLOCK_TIME_NONE;
886 GST_BUFFER_OFFSET (buffer) = GST_BUFFER_OFFSET_NONE;
887 GST_BUFFER_OFFSET_END (buffer) = GST_BUFFER_OFFSET_NONE;
889 /* remove all metadata without the POOLED flag */
890 gst_buffer_foreach_meta (buffer, remove_meta_unpooled, pool);
894 * gst_buffer_pool_acquire_buffer:
895 * @pool: a #GstBufferPool
896 * @buffer: (out): a location for a #GstBuffer
897 * @params: (transfer none) (allow-none) parameters.
899 * Acquire a buffer from @pool. @buffer should point to a memory location that
900 * can hold a pointer to the new buffer.
902 * @params can be NULL or contain optional parameters to influence the allocation.
904 * Returns: a #GstFlowReturn such as GST_FLOW_FLUSHING when the pool is
908 gst_buffer_pool_acquire_buffer (GstBufferPool * pool, GstBuffer ** buffer,
909 GstBufferPoolParams * params)
911 GstBufferPoolClass *pclass;
912 GstFlowReturn result;
914 g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), GST_FLOW_ERROR);
915 g_return_val_if_fail (buffer != NULL, GST_FLOW_ERROR);
917 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
919 /* assume we'll have one more outstanding buffer we need to do that so
920 * that concurrent set_active doesn't clear the buffers */
921 g_atomic_int_inc (&pool->priv->outstanding);
923 if (G_LIKELY (pclass->acquire_buffer))
924 result = pclass->acquire_buffer (pool, buffer, params);
926 result = GST_FLOW_NOT_SUPPORTED;
928 if (G_LIKELY (result == GST_FLOW_OK)) {
929 /* all buffers from the pool point to the pool and have the refcount of the
930 * pool incremented */
931 (*buffer)->pool = gst_object_ref (pool);
932 /* now reset the buffer when needed */
933 if (G_LIKELY (pclass->reset_buffer))
934 pclass->reset_buffer (pool, *buffer, params);
936 dec_outstanding (pool);
943 default_release_buffer (GstBufferPool * pool, GstBuffer * buffer)
945 /* keep it around in our queue */
946 GST_LOG_OBJECT (pool, "released buffer %p", buffer);
947 gst_atomic_queue_push (pool->priv->queue, buffer);
948 gst_poll_write_control (pool->priv->poll);
952 * gst_buffer_pool_release_buffer:
953 * @pool: a #GstBufferPool
954 * @buffer: (transfer none): a #GstBuffer
956 * Release @buffer to @pool. @buffer should have previously been allocated from
957 * @pool with gst_buffer_pool_acquire_buffer().
959 * This function is usually called automatically when the last ref on @buffer
963 gst_buffer_pool_release_buffer (GstBufferPool * pool, GstBuffer * buffer)
965 GstBufferPoolClass *pclass;
967 g_return_if_fail (GST_IS_BUFFER_POOL (pool));
968 g_return_if_fail (buffer != NULL);
970 /* check that the buffer is ours, all buffers returned to the pool have the
971 * pool member set to NULL and the pool refcount decreased */
972 if (!g_atomic_pointer_compare_and_exchange (&buffer->pool, pool, NULL))
975 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
977 if (G_LIKELY (pclass->release_buffer))
978 pclass->release_buffer (pool, buffer);
980 dec_outstanding (pool);
982 /* decrease the refcount that the buffer had to us */
983 gst_object_unref (pool);