X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=gst%2Fgstbufferpool.c;h=f984a26e4c5dbf108da116d9e082548a9cfad773;hb=15f2898e872d3b7ce74ea5fbd35fac9f1f47b4a5;hp=7020345a29cff3cca238ea93ff54ef37fda79345;hpb=393c758a1c2ddf738e4fdc31123cbd5a41fb0b43;p=platform%2Fupstream%2Fgstreamer.git

diff --git a/gst/gstbufferpool.c b/gst/gstbufferpool.c
index 7020345..f984a26 100644
--- a/gst/gstbufferpool.c
+++ b/gst/gstbufferpool.c
@@ -15,26 +15,27 @@
  *
  * You should have received a copy of the GNU Library General Public
  * License along with this library; if not, write to the
- * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- * Boston, MA 02111-1307, USA.
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
  */
 
 /**
  * SECTION:gstbufferpool
+ * @title: GstBufferPool
  * @short_description: Pool for buffers
  * @see_also: #GstBuffer
  *
- * a #GstBufferPool is an object that can be used to pre-allocate and recycle
+ * A #GstBufferPool is an object that can be used to pre-allocate and recycle
  * buffers of the same size and with the same properties.
  *
  * A #GstBufferPool is created with gst_buffer_pool_new().
  *
- * After the buffer is created, it needs to be configured.
- * gst_buffer_pool_get_config() get the current configuration structure from the
- * pool. With gst_buffer_pool_config_set_params() and
- * gst_buffer_pool_config_set_allocator() the bufferpool parameters and allocator
- * can be configured. Other properties can be configured in the pool depending
- * on the pool implementation.
+ * Once a pool is created, it needs to be configured. A call to
+ * gst_buffer_pool_get_config() returns the current configuration structure from
+ * the pool. With gst_buffer_pool_config_set_params() and
+ * gst_buffer_pool_config_set_allocator() the bufferpool parameters and
+ * allocator can be configured. Other properties can be configured in the pool
+ * depending on the pool implementation.
  *
  * A bufferpool can have extra options that can be enabled with
  * gst_buffer_pool_config_add_option(). The available options can be retrieved
@@ -52,8 +53,8 @@
  * When the pool is active, gst_buffer_pool_acquire_buffer() can be used to
  * retrieve a buffer from the pool.
  *
- * Buffer allocated from a bufferpool will automatically be returned to the pool
- * with gst_buffer_pool_release_buffer() when their refcount drops to 0.
+ * Buffers allocated from a bufferpool will automatically be returned to the
+ * pool with gst_buffer_pool_release_buffer() when their refcount drops to 0.
  *
  * The bufferpool can be deactivated again with gst_buffer_pool_set_active().
  * All further gst_buffer_pool_acquire_buffer() calls will return an error. When
@@ -61,8 +62,6 @@
  *
  * Use gst_object_unref() to release the reference to a bufferpool. If the
  * refcount of the pool reaches 0, the pool will be freed.
- *
- * Last reviewed on 2012-03-28 (0.11.3)
  */
 
 #include "gst_private.h"
@@ -82,6 +81,12 @@
 
 #include "gstbufferpool.h"
 
+#ifdef G_OS_WIN32
+#  ifndef EWOULDBLOCK
+#  define EWOULDBLOCK EAGAIN    /* This is just to placate gcc */
+#  endif
+#endif /* G_OS_WIN32 */
+
 GST_DEBUG_CATEGORY_STATIC (gst_buffer_pool_debug);
 #define GST_CAT_DEFAULT gst_buffer_pool_debug
 
@@ -100,7 +105,7 @@ struct _GstBufferPoolPrivate
 
   gboolean started;
   gboolean active;
-  gint outstanding;
+  gint outstanding;             /* number of buffers that are in use */
 
   gboolean configured;
   GstStructure *config;
@@ -108,16 +113,11 @@ struct _GstBufferPoolPrivate
   guint size;
   guint min_buffers;
   guint max_buffers;
+  guint cur_buffers;
   GstAllocator *allocator;
   GstAllocationParams params;
 };
 
-enum
-{
-  /* add more above */
-  LAST_SIGNAL
-};
-
 static void gst_buffer_pool_finalize (GObject * object);
 
 G_DEFINE_TYPE (GstBufferPool, gst_buffer_pool, GST_TYPE_OBJECT);
@@ -130,8 +130,7 @@ static GstFlowReturn default_alloc_buffer (GstBufferPool * pool,
     GstBuffer ** buffer, GstBufferPoolAcquireParams * params);
 static GstFlowReturn default_acquire_buffer (GstBufferPool * pool,
     GstBuffer ** buffer, GstBufferPoolAcquireParams * params);
-static void default_reset_buffer (GstBufferPool * pool, GstBuffer * buffer,
-    GstBufferPoolAcquireParams * params);
+static void default_reset_buffer (GstBufferPool * pool, GstBuffer * buffer);
 static void default_free_buffer (GstBufferPool * pool, GstBuffer * buffer);
 static void default_release_buffer (GstBufferPool * pool, GstBuffer * buffer);
 
@@ -167,7 +166,7 @@ gst_buffer_pool_init (GstBufferPool * pool)
   g_rec_mutex_init (&priv->rec_lock);
 
   priv->poll = gst_poll_new_timer ();
-  priv->queue = gst_atomic_queue_new (10);
+  priv->queue = gst_atomic_queue_new (16);
   pool->flushing = 1;
   priv->active = FALSE;
   priv->configured = FALSE;
@@ -178,6 +177,9 @@ gst_buffer_pool_init (GstBufferPool * pool)
   gst_allocation_params_init (&priv->params);
   gst_buffer_pool_config_set_allocator (priv->config, priv->allocator,
       &priv->params);
+  /* 1 control write for flushing - the flush token */
+  gst_poll_write_control (priv->poll);
+  /* 1 control write for marking that we are not waiting for poll - the wait token */
   gst_poll_write_control (priv->poll);
 
   GST_DEBUG_OBJECT (pool, "created");
@@ -192,7 +194,7 @@ gst_buffer_pool_finalize (GObject * object)
   pool = GST_BUFFER_POOL_CAST (object);
   priv = pool->priv;
 
-  GST_DEBUG_OBJECT (pool, "finalize");
+  GST_DEBUG_OBJECT (pool, "%p finalize", pool);
 
   gst_buffer_pool_set_active (pool, FALSE);
   gst_atomic_queue_unref (priv->queue);
@@ -200,7 +202,7 @@ gst_buffer_pool_finalize (GObject * object)
   gst_structure_free (priv->config);
   g_rec_mutex_clear (&priv->rec_lock);
   if (priv->allocator)
-    gst_allocator_unref (priv->allocator);
+    gst_object_unref (priv->allocator);
 
   G_OBJECT_CLASS (gst_buffer_pool_parent_class)->finalize (object);
 }
@@ -210,7 +212,7 @@ gst_buffer_pool_finalize (GObject * object)
  *
  * Creates a new #GstBufferPool instance.
  *
- * Returns: (transfer full): a new #GstBufferPool instance
+ * Returns: (transfer floating): a new #GstBufferPool instance
  */
 GstBufferPool *
 gst_buffer_pool_new (void)
@@ -232,23 +234,83 @@ default_alloc_buffer (GstBufferPool * pool, GstBuffer ** buffer,
   *buffer =
       gst_buffer_new_allocate (priv->allocator, priv->size, &priv->params);
 
+  if (!*buffer)
+    return GST_FLOW_ERROR;
+
   return GST_FLOW_OK;
 }
 
 static gboolean
 mark_meta_pooled (GstBuffer * buffer, GstMeta ** meta, gpointer user_data)
 {
-  GstBufferPool *pool = user_data;
-
-  GST_DEBUG_OBJECT (pool, "marking meta %p as POOLED in buffer %p", *meta,
-      buffer);
+  GST_DEBUG_OBJECT (GST_BUFFER_POOL (user_data),
+      "marking meta %p as POOLED in buffer %p", *meta, buffer);
   GST_META_FLAG_SET (*meta, GST_META_FLAG_POOLED);
+  GST_META_FLAG_SET (*meta, GST_META_FLAG_LOCKED);
 
   return TRUE;
 }
 
-/* the default implementation for preallocating the buffers
- * in the pool */
+static GstFlowReturn
+do_alloc_buffer (GstBufferPool * pool, GstBuffer ** buffer,
+    GstBufferPoolAcquireParams * params)
+{
+  GstBufferPoolPrivate *priv = pool->priv;
+  GstFlowReturn result;
+  gint cur_buffers, max_buffers;
+  GstBufferPoolClass *pclass;
+
+  pclass = GST_BUFFER_POOL_GET_CLASS (pool);
+
+  if (G_UNLIKELY (!pclass->alloc_buffer))
+    goto no_function;
+
+  max_buffers = priv->max_buffers;
+
+  /* increment the allocation counter */
+  cur_buffers = g_atomic_int_add (&priv->cur_buffers, 1);
+  if (max_buffers && cur_buffers >= max_buffers)
+    goto max_reached;
+
+  result = pclass->alloc_buffer (pool, buffer, params);
+  if (G_UNLIKELY (result != GST_FLOW_OK))
+    goto alloc_failed;
+
+  /* lock all metadata and mark as pooled, we want this to remain on
+   * the buffer and we want to remove any other metadata that gets added
+   * later */
+  gst_buffer_foreach_meta (*buffer, mark_meta_pooled, pool);
+
+  /* un-tag memory, this is how we expect the buffer when it is
+   * released again */
+  GST_BUFFER_FLAG_UNSET (*buffer, GST_BUFFER_FLAG_TAG_MEMORY);
+
+  GST_LOG_OBJECT (pool, "allocated buffer %d/%d, %p", cur_buffers,
+      max_buffers, *buffer);
+
+  return result;
+
+  /* ERRORS */
+no_function:
+  {
+    GST_ERROR_OBJECT (pool, "no alloc function");
+    return GST_FLOW_NOT_SUPPORTED;
+  }
+max_reached:
+  {
+    GST_DEBUG_OBJECT (pool, "max buffers reached");
+    g_atomic_int_add (&priv->cur_buffers, -1);
+    return GST_FLOW_EOS;
+  }
+alloc_failed:
+  {
+    GST_WARNING_OBJECT (pool, "alloc function failed");
+    g_atomic_int_add (&priv->cur_buffers, -1);
+    return result;
+  }
+}
+
+/* the default implementation for preallocating the buffers in the pool */
 static gboolean
 default_start (GstBufferPool * pool)
 {
@@ -258,19 +320,13 @@ default_start (GstBufferPool * pool)
 
   pclass = GST_BUFFER_POOL_GET_CLASS (pool);
 
-  /* no alloc function, error */
-  if (G_UNLIKELY (pclass->alloc_buffer == NULL))
-    goto no_alloc;
-
   /* we need to prealloc buffers */
   for (i = 0; i < priv->min_buffers; i++) {
     GstBuffer *buffer;
 
-    if (pclass->alloc_buffer (pool, &buffer, NULL) != GST_FLOW_OK)
+    if (do_alloc_buffer (pool, &buffer, NULL) != GST_FLOW_OK)
       goto alloc_failed;
 
-    gst_buffer_foreach_meta (buffer, mark_meta_pooled, pool);
-    GST_LOG_OBJECT (pool, "prealloced buffer %d: %p", i, buffer);
     /* release to the queue, we call the vmethod directly, we don't need to do
      * the other refcount handling right now. */
     if (G_LIKELY (pclass->release_buffer))
@@ -279,14 +335,9 @@ default_start (GstBufferPool * pool)
   return TRUE;
 
   /* ERRORS */
-no_alloc:
-  {
-    GST_WARNING_OBJECT (pool, "no alloc function");
-    return FALSE;
-  }
 alloc_failed:
   {
-    GST_WARNING_OBJECT (pool, "alloc function failed");
+    GST_WARNING_OBJECT (pool, "failed to allocate buffer");
     return FALSE;
   }
 }
@@ -295,7 +346,9 @@ alloc_failed:
 static gboolean
 do_start (GstBufferPool * pool)
 {
-  if (!pool->priv->started) {
+  GstBufferPoolPrivate *priv = pool->priv;
+
+  if (!priv->started) {
     GstBufferPoolClass *pclass;
 
     pclass = GST_BUFFER_POOL_GET_CLASS (pool);
@@ -307,43 +360,66 @@ do_start (GstBufferPool * pool)
       if (!pclass->start (pool))
         return FALSE;
     }
-    pool->priv->started = TRUE;
+    priv->started = TRUE;
   }
   return TRUE;
 }
 
-
 static void
 default_free_buffer (GstBufferPool * pool, GstBuffer * buffer)
 {
   gst_buffer_unref (buffer);
 }
 
+static void
+do_free_buffer (GstBufferPool * pool, GstBuffer * buffer)
+{
+  GstBufferPoolPrivate *priv;
+  GstBufferPoolClass *pclass;
+
+  priv = pool->priv;
+  pclass = GST_BUFFER_POOL_GET_CLASS (pool);
+
+  g_atomic_int_add (&priv->cur_buffers, -1);
+  GST_LOG_OBJECT (pool, "freeing buffer %p (%u left)", buffer,
+      priv->cur_buffers);
+
+  if (G_LIKELY (pclass->free_buffer))
+    pclass->free_buffer (pool, buffer);
+}
+
 /* must be called with the lock */
 static gboolean
 default_stop (GstBufferPool * pool)
 {
+  GstBufferPoolPrivate *priv = pool->priv;
   GstBuffer *buffer;
-  GstBufferPoolClass *pclass;
-
-  pclass = GST_BUFFER_POOL_GET_CLASS (pool);
 
   /* clear the pool */
-  while ((buffer = gst_atomic_queue_pop (pool->priv->queue))) {
-    GST_LOG_OBJECT (pool, "freeing %p", buffer);
-    gst_poll_read_control (pool->priv->poll);
-
-    if (G_LIKELY (pclass->free_buffer))
-      pclass->free_buffer (pool, buffer);
+  while ((buffer = gst_atomic_queue_pop (priv->queue))) {
+    while (!gst_poll_read_control (priv->poll)) {
+      if (errno == EWOULDBLOCK) {
+        /* We put the buffer into the queue but did not finish writing control
+         * yet, let's wait a bit and retry */
+        g_thread_yield ();
+        continue;
+      } else {
+        /* Critical error but GstPoll already complained */
+        break;
+      }
+    }
+    do_free_buffer (pool, buffer);
   }
-  return TRUE;
+  return priv->cur_buffers == 0;
 }
 
 /* must be called with the lock */
 static gboolean
 do_stop (GstBufferPool * pool)
 {
-  if (pool->priv->started) {
+  GstBufferPoolPrivate *priv = pool->priv;
+
+  if (priv->started) {
     GstBufferPoolClass *pclass;
 
     pclass = GST_BUFFER_POOL_GET_CLASS (pool);
@@ -353,18 +429,58 @@ do_stop (GstBufferPool * pool)
       if (!pclass->stop (pool))
         return FALSE;
     }
-    pool->priv->started = FALSE;
+    priv->started = FALSE;
   }
   return TRUE;
 }
 
+/* must be called with the lock */
+static void
+do_set_flushing (GstBufferPool * pool, gboolean flushing)
+{
+  GstBufferPoolPrivate *priv = pool->priv;
+  GstBufferPoolClass *pclass;
+
+  pclass = GST_BUFFER_POOL_GET_CLASS (pool);
+
+  if (GST_BUFFER_POOL_IS_FLUSHING (pool) == flushing)
+    return;
+
+  if (flushing) {
+    g_atomic_int_set (&pool->flushing, 1);
+    /* Write the flush token to wake up any waiters */
+    gst_poll_write_control (priv->poll);
+
+    if (pclass->flush_start)
+      pclass->flush_start (pool);
+  } else {
+    if (pclass->flush_stop)
+      pclass->flush_stop (pool);
+
+    while (!gst_poll_read_control (priv->poll)) {
+      if (errno == EWOULDBLOCK) {
+        /* This should not really happen unless flushing and unflushing
+         * happens on different threads. Let's wait a bit to get back flush
+         * token from the thread that was setting it to flushing */
+        g_thread_yield ();
+        continue;
+      } else {
+        /* Critical error but GstPoll already complained */
+        break;
+      }
+    }
+
+    g_atomic_int_set (&pool->flushing, 0);
+  }
+}
+
 /**
  * gst_buffer_pool_set_active:
  * @pool: a #GstBufferPool
  * @active: the new active state
  *
- * Control the active state of @pool. When the pool is active, new calls to
- * gst_buffer_pool_acquire_buffer() will return with GST_FLOW_FLUSHING.
+ * Control the active state of @pool. When the pool is inactive, new calls to
+ * gst_buffer_pool_acquire_buffer() will return with %GST_FLOW_FLUSHING.
  *
  * Activating the bufferpool will preallocate all resources in the pool based on
  * the configuration of the pool.
@@ -380,44 +496,50 @@ gboolean
 gst_buffer_pool_set_active (GstBufferPool * pool, gboolean active)
 {
   gboolean res = TRUE;
+  GstBufferPoolPrivate *priv;
 
   g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), FALSE);
 
   GST_LOG_OBJECT (pool, "active %d", active);
 
+  priv = pool->priv;
+
   GST_BUFFER_POOL_LOCK (pool);
   /* just return if we are already in the right state */
-  if (pool->priv->active == active)
+  if (priv->active == active)
     goto was_ok;
 
   /* we need to be configured */
-  if (!pool->priv->configured)
+  if (!priv->configured)
     goto not_configured;
 
   if (active) {
     if (!do_start (pool))
       goto start_failed;
 
+    /* flush_stop my release buffers, setting to active to avoid running
+     * do_stop while activating the pool */
+    priv->active = TRUE;
+
     /* unset the flushing state now */
-    gst_poll_read_control (pool->priv->poll);
-    g_atomic_int_set (&pool->flushing, 0);
+    do_set_flushing (pool, FALSE);
   } else {
     gint outstanding;
 
     /* set to flushing first */
-    g_atomic_int_set (&pool->flushing, 1);
-    gst_poll_write_control (pool->priv->poll);
+    do_set_flushing (pool, TRUE);
 
     /* when all buffers are in the pool, free them. Else they will be
      * freed when they are released */
-    outstanding = g_atomic_int_get (&pool->priv->outstanding);
+    outstanding = g_atomic_int_get (&priv->outstanding);
     GST_LOG_OBJECT (pool, "outstanding buffers %d", outstanding);
     if (outstanding == 0) {
       if (!do_stop (pool))
         goto stop_failed;
     }
+
+    priv->active = FALSE;
   }
-  pool->priv->active = active;
   GST_BUFFER_POOL_UNLOCK (pool);
 
   return res;
@@ -491,11 +613,12 @@ default_set_config (GstBufferPool * pool, GstStructure * config)
   priv->size = size;
   priv->min_buffers = min_buffers;
   priv->max_buffers = max_buffers;
+  priv->cur_buffers = 0;
 
   if (priv->allocator)
-    gst_allocator_unref (priv->allocator);
+    gst_object_unref (priv->allocator);
   if ((priv->allocator = allocator))
-    gst_allocator_ref (allocator);
+    gst_object_ref (allocator);
   priv->params = params;
 
   return TRUE;
@@ -512,32 +635,49 @@ wrong_config:
  * @pool: a #GstBufferPool
  * @config: (transfer full): a #GstStructure
  *
- * Set the configuration of the pool. The pool must be inactive and all buffers
- * allocated form this pool must be returned or else this function will do
- * nothing and return FALSE.
+ * Set the configuration of the pool. If the pool is already configured, and
+ * the configuration haven't change, this function will return %TRUE. If the
+ * pool is active, this method will return %FALSE and active configuration
+ * will remain. Buffers allocated form this pool must be returned or else this
+ * function will do nothing and return %FALSE.
  *
  * @config is a #GstStructure that contains the configuration parameters for
  * the pool. A default and mandatory set of parameters can be configured with
- * gst_buffer_pool_config_set(). This function takes ownership of @config.
+ * gst_buffer_pool_config_set_params(), gst_buffer_pool_config_set_allocator()
+ * and gst_buffer_pool_config_add_option().
+ *
+ * If the parameters in @config can not be set exactly, this function returns
+ * %FALSE and will try to update as much state as possible. The new state can
+ * then be retrieved and refined with gst_buffer_pool_get_config().
+ *
+ * This function takes ownership of @config.
  *
- * Returns: TRUE when the configuration could be set.
+ * Returns: %TRUE when the configuration could be set.
  */
 gboolean
 gst_buffer_pool_set_config (GstBufferPool * pool, GstStructure * config)
 {
   gboolean result;
   GstBufferPoolClass *pclass;
+  GstBufferPoolPrivate *priv;
 
   g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), FALSE);
   g_return_val_if_fail (config != NULL, FALSE);
 
+  priv = pool->priv;
+
   GST_BUFFER_POOL_LOCK (pool);
+
+  /* nothing to do if config is unchanged */
+  if (priv->configured && gst_structure_is_equal (config, priv->config))
+    goto config_unchanged;
+
   /* can't change the settings when active */
-  if (pool->priv->active)
+  if (priv->active)
     goto was_active;
 
   /* we can't change when outstanding buffers */
-  if (g_atomic_int_get (&pool->priv->outstanding) != 0)
+  if (g_atomic_int_get (&priv->outstanding) != 0)
     goto have_outstanding;
 
   pclass = GST_BUFFER_POOL_GET_CLASS (pool);
@@ -548,25 +688,31 @@ gst_buffer_pool_set_config (GstBufferPool * pool, GstStructure * config)
   else
     result = FALSE;
 
-  if (result) {
-    if (pool->priv->config)
-      gst_structure_free (pool->priv->config);
-    pool->priv->config = config;
+  /* save the config regardless of the result so user can read back the
+   * modified config and evaluate if the changes are acceptable */
+  if (priv->config)
+    gst_structure_free (priv->config);
+  priv->config = config;
 
+  if (result) {
     /* now we are configured */
-    pool->priv->configured = TRUE;
-  } else {
-    gst_structure_free (config);
+    priv->configured = TRUE;
   }
   GST_BUFFER_POOL_UNLOCK (pool);
 
   return result;
 
+config_unchanged:
+  {
+    gst_structure_free (config);
+    GST_BUFFER_POOL_UNLOCK (pool);
+    return TRUE;
+  }
   /* ERRORS */
 was_active:
   {
     gst_structure_free (config);
-    GST_WARNING_OBJECT (pool, "can't change config, we are active");
+    GST_INFO_OBJECT (pool, "can't change config, we are active");
     GST_BUFFER_POOL_UNLOCK (pool);
     return FALSE;
   }
@@ -597,7 +743,7 @@ gst_buffer_pool_get_config (GstBufferPool * pool)
 
   g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), NULL);
 
-  GST_BUFFER_POOL_UNLOCK (pool);
+  GST_BUFFER_POOL_LOCK (pool);
   result = gst_structure_copy (pool->priv->config);
   GST_BUFFER_POOL_UNLOCK (pool);
 
@@ -610,11 +756,12 @@ static const gchar *empty_option[] = { NULL };
  * gst_buffer_pool_get_options:
  * @pool: a #GstBufferPool
  *
- * Get a NULL terminated array of string with supported bufferpool options for
+ * Get a %NULL terminated array of string with supported bufferpool options for
  * @pool. An option would typically be enabled with
  * gst_buffer_pool_config_add_option().
  *
- * Returns: (array zero-terminated=1) (transfer none): a NULL terminated array of strings.
+ * Returns: (array zero-terminated=1) (transfer none): a %NULL terminated array
+ *          of strings.
  */
 const gchar **
 gst_buffer_pool_get_options (GstBufferPool * pool)
@@ -649,7 +796,7 @@ invalid_result:
  *
  * Check if the bufferpool supports @option.
  *
- * Returns: a NULL terminated array of strings.
+ * Returns: %TRUE if the buffer pool contains @option.
  */
 gboolean
 gst_buffer_pool_has_option (GstBufferPool * pool, const gchar * option)
@@ -685,6 +832,7 @@ gst_buffer_pool_config_set_params (GstStructure * config, GstCaps * caps,
 {
   g_return_if_fail (config != NULL);
   g_return_if_fail (max_buffers == 0 || min_buffers <= max_buffers);
+  g_return_if_fail (caps == NULL || gst_caps_is_fixed (caps));
 
   gst_structure_id_set (config,
       GST_QUARK (CAPS), GST_TYPE_CAPS, caps,
@@ -696,15 +844,15 @@ gst_buffer_pool_config_set_params (GstStructure * config, GstCaps * caps,
 /**
  * gst_buffer_pool_config_set_allocator:
  * @config: a #GstBufferPool configuration
- * @allocator: a #GstAllocator
- * @params: #GstAllocationParams
+ * @allocator: (allow-none): a #GstAllocator
+ * @params: (allow-none): #GstAllocationParams
  *
  * Set the @allocator and @params on @config.
  *
- * One of @allocator and @params can be NULL, but not both. When @allocator
- * is NULL, the default allocator of the pool will use the values in @param
- * to perform its allocation. When @param is NULL, the pool will use the
- * provided allocator with its default #GstAllocationParams.
+ * One of @allocator and @params can be %NULL, but not both. When @allocator
+ * is %NULL, the default allocator of the pool will use the values in @param
+ * to perform its allocation. When @param is %NULL, the pool will use the
+ * provided @allocator with its default #GstAllocationParams.
  *
  * A call to gst_buffer_pool_set_config() can update the allocator and params
  * with the values that it is able to do. Some pools are, for example, not able
@@ -761,16 +909,15 @@ gst_buffer_pool_config_add_option (GstStructure * config, const gchar * option)
   }
   g_value_init (&option_value, G_TYPE_STRING);
   g_value_set_string (&option_value, option);
-  gst_value_array_append_value ((GValue *) value, &option_value);
-  g_value_unset (&option_value);
+  gst_value_array_append_and_take_value ((GValue *) value, &option_value);
 }
 
 /**
  * gst_buffer_pool_config_n_options:
  * @config: a #GstBufferPool configuration
  *
- * Retrieve the number of values currently stored in the
- * options array of the @config structure.
+ * Retrieve the number of values currently stored in the options array of the
+ * @config structure.
  *
  * Returns: the options array size as a #guint.
  */
@@ -794,8 +941,8 @@ gst_buffer_pool_config_n_options (GstStructure * config)
  * @config: a #GstBufferPool configuration
  * @index: position in the option array to read
  *
- * Parse an available @config and get the option
- * at @index of the options API array.
+ * Parse an available @config and get the option at @index of the options API
+ * array.
  *
  * Returns: a #gchar of the option at @index.
  */
@@ -823,9 +970,9 @@ gst_buffer_pool_config_get_option (GstStructure * config, guint index)
  * @config: a #GstBufferPool configuration
  * @option: an option
  *
- * Check if @config contains @option
+ * Check if @config contains @option.
  *
- * Returns: TRUE if the options array contains @option.
+ * Returns: %TRUE if the options array contains @option.
  */
 gboolean
 gst_buffer_pool_config_has_option (GstStructure * config, const gchar * option)
@@ -879,10 +1026,12 @@ gst_buffer_pool_config_get_params (GstStructure * config, GstCaps ** caps,
 /**
  * gst_buffer_pool_config_get_allocator:
  * @config: (transfer none): a #GstBufferPool configuration
- * @allocator: (transfer none): a #GstAllocator
- * @params: #GstAllocationParams
+ * @allocator: (out) (allow-none) (transfer none): a #GstAllocator, or %NULL
+ * @params: (out) (allow-none): #GstAllocationParams, or %NULL
  *
- * Get the allocator and params from @config.
+ * Get the @allocator and @params from @config.
+ *
+ * Returns: %TRUE, if the values are set.
  */
 gboolean
 gst_buffer_pool_config_get_allocator (GstStructure * config,
@@ -891,7 +1040,7 @@ gst_buffer_pool_config_get_allocator (GstStructure * config,
   g_return_val_if_fail (config != NULL, FALSE);
 
   if (allocator)
-    *allocator = g_value_get_boxed (gst_structure_id_get_value (config,
+    *allocator = g_value_get_object (gst_structure_id_get_value (config,
             GST_QUARK (ALLOCATOR)));
   if (params) {
     GstAllocationParams *p;
@@ -907,54 +1056,122 @@ gst_buffer_pool_config_get_allocator (GstStructure * config,
   return TRUE;
 }
 
+/**
+ * gst_buffer_pool_config_validate_params:
+ * @config: (transfer none): a #GstBufferPool configuration
+ * @caps: (transfer none): the excepted caps of buffers
+ * @size: the expected size of each buffer, not including prefix and padding
+ * @min_buffers: the expected minimum amount of buffers to allocate.
+ * @max_buffers: the expect maximum amount of buffers to allocate or 0 for unlimited.
+ *
+ * Validate that changes made to @config are still valid in the context of the
+ * expected parameters. This function is a helper that can be used to validate
+ * changes made by a pool to a config when gst_buffer_pool_set_config()
+ * returns %FALSE. This expects that @caps haven't changed and that
+ * @min_buffers aren't lower then what we initially expected.
+ * This does not check if options or allocator parameters are still valid,
+ * won't check if size have changed, since changing the size is valid to adapt
+ * padding.
+ *
+ * Since: 1.4
+ *
+ * Returns: %TRUE, if the parameters are valid in this context.
+ */
+gboolean
+gst_buffer_pool_config_validate_params (GstStructure * config, GstCaps * caps,
+    guint size, guint min_buffers, G_GNUC_UNUSED guint max_buffers)
+{
+  GstCaps *newcaps;
+  guint newsize, newmin;
+  gboolean ret = FALSE;
+
+  g_return_val_if_fail (config != NULL, FALSE);
+
+  gst_buffer_pool_config_get_params (config, &newcaps, &newsize, &newmin, NULL);
+
+  if (gst_caps_is_equal (caps, newcaps) && (newsize >= size)
+      && (newmin >= min_buffers))
+    ret = TRUE;
+
+  return ret;
+}
+
 static GstFlowReturn
 default_acquire_buffer (GstBufferPool * pool, GstBuffer ** buffer,
     GstBufferPoolAcquireParams * params)
 {
   GstFlowReturn result;
-  GstBufferPoolClass *pclass;
   GstBufferPoolPrivate *priv = pool->priv;
 
-  pclass = GST_BUFFER_POOL_GET_CLASS (pool);
-
   while (TRUE) {
     if (G_UNLIKELY (GST_BUFFER_POOL_IS_FLUSHING (pool)))
       goto flushing;
 
     /* try to get a buffer from the queue */
-    *buffer = gst_atomic_queue_pop (pool->priv->queue);
+    *buffer = gst_atomic_queue_pop (priv->queue);
     if (G_LIKELY (*buffer)) {
-      gst_poll_read_control (pool->priv->poll);
+      while (!gst_poll_read_control (priv->poll)) {
+        if (errno == EWOULDBLOCK) {
+          /* We put the buffer into the queue but did not finish writing control
+           * yet, let's wait a bit and retry */
+          g_thread_yield ();
+          continue;
+        } else {
+          /* Critical error but GstPoll already complained */
+          break;
+        }
+      }
       result = GST_FLOW_OK;
       GST_LOG_OBJECT (pool, "acquired buffer %p", *buffer);
       break;
     }
 
-    /* no buffer */
-    if (priv->max_buffers == 0) {
-      /* no max_buffers, we allocate some more */
-      if (G_LIKELY (pclass->alloc_buffer)) {
-        result = pclass->alloc_buffer (pool, buffer, params);
-        if (result == GST_FLOW_OK && *buffer)
-          gst_buffer_foreach_meta (*buffer, mark_meta_pooled, pool);
-        else
-          result = GST_FLOW_ERROR;
-      } else
-        result = GST_FLOW_NOT_SUPPORTED;
-      GST_LOG_OBJECT (pool, "alloc buffer %p", *buffer);
+    /* no buffer, try to allocate some more */
+    GST_LOG_OBJECT (pool, "no buffer, trying to allocate");
+    result = do_alloc_buffer (pool, buffer, params);
+    if (G_LIKELY (result == GST_FLOW_OK))
+      /* we have a buffer, return it */
+      break;
+
+    if (G_UNLIKELY (result != GST_FLOW_EOS))
+      /* something went wrong, return error */
       break;
-    }
 
     /* check if we need to wait */
     if (params && (params->flags & GST_BUFFER_POOL_ACQUIRE_FLAG_DONTWAIT)) {
       GST_LOG_OBJECT (pool, "no more buffers");
-      result = GST_FLOW_EOS;
       break;
     }
 
-    /* now wait */
-    GST_LOG_OBJECT (pool, "waiting for free buffers");
-    gst_poll_wait (pool->priv->poll, GST_CLOCK_TIME_NONE);
+    /* now we release the control socket, we wait for a buffer release or
+     * flushing */
+    if (!gst_poll_read_control (pool->priv->poll)) {
+      if (errno == EWOULDBLOCK) {
+        /* This means that we have two threads trying to allocate buffers
+         * already, and the other one already got the wait token. This
+         * means that we only have to wait for the poll now and not write the
+         * token afterwards: we will be woken up once the other thread is
+         * woken up and that one will write the wait token it removed */
+        GST_LOG_OBJECT (pool, "waiting for free buffers or flushing");
+        gst_poll_wait (priv->poll, GST_CLOCK_TIME_NONE);
+      } else {
+        /* This is a critical error, GstPoll already gave a warning */
+        result = GST_FLOW_ERROR;
+        break;
+      }
+    } else {
+      /* We're the first thread waiting, we got the wait token and have to
+       * write it again later
+       * OR
+       * We're a second thread and just consumed the flush token and block all
+       * other threads, in which case we must not wait and give it back
+       * immediately */
+      if (!GST_BUFFER_POOL_IS_FLUSHING (pool)) {
+        GST_LOG_OBJECT (pool, "waiting for free buffers or flushing");
+        gst_poll_wait (priv->poll, GST_CLOCK_TIME_NONE);
+      }
+      gst_poll_write_control (pool->priv->poll);
+    }
   }
 
   return result;
@@ -975,9 +1192,9 @@ dec_outstanding (GstBufferPool * pool)
     if (GST_BUFFER_POOL_IS_FLUSHING (pool)) {
       /* take the lock so that set_active is not run concurrently */
       GST_BUFFER_POOL_LOCK (pool);
-      /* recheck the flushing state in the lock, the pool could have been
-       * set to active again */
-      if (GST_BUFFER_POOL_IS_FLUSHING (pool))
+      /* now that we have the lock, check if we have been de-activated with
+       * outstanding buffers */
+      if (!pool->priv->active)
         do_stop (pool);
 
       GST_BUFFER_POOL_UNLOCK (pool);
@@ -988,16 +1205,17 @@ dec_outstanding (GstBufferPool * pool)
 static gboolean
 remove_meta_unpooled (GstBuffer * buffer, GstMeta ** meta, gpointer user_data)
 {
-  if (!GST_META_FLAG_IS_SET (*meta, GST_META_FLAG_POOLED))
+  if (!GST_META_FLAG_IS_SET (*meta, GST_META_FLAG_POOLED)) {
+    GST_META_FLAG_UNSET (*meta, GST_META_FLAG_LOCKED);
     *meta = NULL;
+  }
   return TRUE;
 }
 
 static void
-default_reset_buffer (GstBufferPool * pool, GstBuffer * buffer,
-    GstBufferPoolAcquireParams * params)
+default_reset_buffer (GstBufferPool * pool, GstBuffer * buffer)
 {
-  GST_BUFFER_FLAGS (buffer) = 0;
+  GST_BUFFER_FLAGS (buffer) &= GST_BUFFER_FLAG_TAG_MEMORY;
 
   GST_BUFFER_PTS (buffer) = GST_CLOCK_TIME_NONE;
   GST_BUFFER_DTS (buffer) = GST_CLOCK_TIME_NONE;
@@ -1013,14 +1231,15 @@ default_reset_buffer (GstBufferPool * pool, GstBuffer * buffer,
  * gst_buffer_pool_acquire_buffer:
  * @pool: a #GstBufferPool
  * @buffer: (out): a location for a #GstBuffer
- * @params: (transfer none) (allow-none) parameters.
+ * @params: (transfer none) (allow-none): parameters.
  *
  * Acquire a buffer from @pool. @buffer should point to a memory location that
  * can hold a pointer to the new buffer.
  *
- * @params can be NULL or contain optional parameters to influence the allocation.
+ * @params can be %NULL or contain optional parameters to influence the
+ * allocation.
  *
- * Returns: a #GstFlowReturn such as GST_FLOW_FLUSHING when the pool is
+ * Returns: a #GstFlowReturn such as %GST_FLOW_FLUSHING when the pool is
  * inactive.
  */
 GstFlowReturn
@@ -1048,9 +1267,6 @@ gst_buffer_pool_acquire_buffer (GstBufferPool * pool, GstBuffer ** buffer,
     /* all buffers from the pool point to the pool and have the refcount of the
      * pool incremented */
     (*buffer)->pool = gst_object_ref (pool);
-    /* now reset the buffer when needed */
-    if (G_LIKELY (pclass->reset_buffer))
-      pclass->reset_buffer (pool, *buffer, params);
   } else {
     dec_outstanding (pool);
   }
@@ -1061,10 +1277,52 @@ gst_buffer_pool_acquire_buffer (GstBufferPool * pool, GstBuffer ** buffer,
 static void
 default_release_buffer (GstBufferPool * pool, GstBuffer * buffer)
 {
+  GST_LOG_OBJECT (pool, "released buffer %p %d", buffer,
+      GST_MINI_OBJECT_FLAGS (buffer));
+
+  /* memory should be untouched */
+  if (G_UNLIKELY (GST_BUFFER_FLAG_IS_SET (buffer, GST_BUFFER_FLAG_TAG_MEMORY)))
+    goto memory_tagged;
+
+  /* size should have been reset. This is not a catch all, pool with
+   * size requirement per memory should do their own check. */
+  if (G_UNLIKELY (gst_buffer_get_size (buffer) != pool->priv->size))
+    goto size_changed;
+
+  /* all memory should be exclusive to this buffer (and thus be writable) */
+  if (G_UNLIKELY (!gst_buffer_is_all_memory_writable (buffer)))
+    goto not_writable;
+
   /* keep it around in our queue */
-  GST_LOG_OBJECT (pool, "released buffer %p", buffer);
   gst_atomic_queue_push (pool->priv->queue, buffer);
   gst_poll_write_control (pool->priv->poll);
+
+  return;
+
+memory_tagged:
+  {
+    GST_CAT_DEBUG_OBJECT (GST_CAT_PERFORMANCE, pool,
+        "discarding buffer %p: memory tag set", buffer);
+    goto discard;
+  }
+size_changed:
+  {
+    GST_CAT_DEBUG_OBJECT (GST_CAT_PERFORMANCE, pool,
+        "discarding buffer %p: size %" G_GSIZE_FORMAT " != %u",
+        buffer, gst_buffer_get_size (buffer), pool->priv->size);
+    goto discard;
+  }
+not_writable:
+  {
+    GST_CAT_DEBUG_OBJECT (GST_CAT_PERFORMANCE, pool,
+        "discarding buffer %p: memory not writable", buffer);
+    goto discard;
+  }
+discard:
+  {
+    do_free_buffer (pool, buffer);
+    return;
+  }
 }
 
 /**
@@ -1093,6 +1351,10 @@ gst_buffer_pool_release_buffer (GstBufferPool * pool, GstBuffer * buffer)
 
   pclass = GST_BUFFER_POOL_GET_CLASS (pool);
 
+  /* reset the buffer when needed */
+  if (G_LIKELY (pclass->reset_buffer))
+    pclass->reset_buffer (pool, buffer);
+
   if (G_LIKELY (pclass->release_buffer))
     pclass->release_buffer (pool, buffer);
 
@@ -1101,3 +1363,37 @@ gst_buffer_pool_release_buffer (GstBufferPool * pool, GstBuffer * buffer)
   /* decrease the refcount that the buffer had to us */
   gst_object_unref (pool);
 }
+
+/**
+ * gst_buffer_pool_set_flushing:
+ * @pool: a #GstBufferPool
+ * @flushing: whether to start or stop flushing
+ *
+ * Enable or disable the flushing state of a @pool without freeing or
+ * allocating buffers.
+ *
+ * Since: 1.4
+ */
+void
+gst_buffer_pool_set_flushing (GstBufferPool * pool, gboolean flushing)
+{
+  GstBufferPoolPrivate *priv;
+
+  g_return_if_fail (GST_IS_BUFFER_POOL (pool));
+
+  GST_LOG_OBJECT (pool, "flushing %d", flushing);
+
+  priv = pool->priv;
+
+  GST_BUFFER_POOL_LOCK (pool);
+
+  if (!priv->active) {
+    GST_WARNING_OBJECT (pool, "can't change flushing state of inactive pool");
+    goto done;
+  }
+
+  do_set_flushing (pool, flushing);
+
+done:
+  GST_BUFFER_POOL_UNLOCK (pool);
+}