gstreamer/libs/gst/base/gstdataqueue.h
Thiago Santos 581c4297d0 dataqueue: add gst_data_queue_push_force
Adds a variant of the _push function that doesn't check the queue limits
before adding the new item. It is useful when pushing an element to the
queue shouldn't lock the thread.

One particular scenario is when the queue is used to serialize buffers
and events that are going to be pushed from another thread. The
dataqueue should have a limit on the amount of buffers to be stored to
avoid large memory consumption, but events can be considered to have
negligible impact on memory compared to buffers. So it is useful to be
used to push items into the queue that contain events, even though the
queue is already full, it shouldn't matter inserting an item that has
no significative size.

This scenario happens on adaptive elements (dashdemux / mssdemux) as
there is a single download thread fetching buffers and putting into the
dataqueues for the streams. This same download thread can als generate
events in some situations as caps changes, eos or a internal control
events. There can be a deadlock at preroll if the first buffer fetched
is large enough to fill the dataqueue and the download thread and the
next iteration of the download thread decides to push an event to this
same dataqueue before fetching buffers to other streams, if this push
locks, the pipeline will be stuck in preroll as no more buffers will be
downloaded.
There is a somewhat common practice in dash streams to have a single
very large buffer for audio and one for video, so this will always
happen as the download thread will have to push an EOS right after
fetching the first buffer for any stream.

API: gst_data_queue_push_force

https://bugzilla.gnome.org/show_bug.cgi?id=705694
2013-08-13 12:00:48 -03:00

163 lines
5.1 KiB
C

/* GStreamer
* Copyright (C) 2006 Edward Hervey <edward@fluendo.com>
*
* gstdataqueue.h:
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* 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., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#ifndef __GST_DATA_QUEUE_H__
#define __GST_DATA_QUEUE_H__
#include <gst/gst.h>
G_BEGIN_DECLS
#define GST_TYPE_DATA_QUEUE \
(gst_data_queue_get_type())
#define GST_DATA_QUEUE(obj) \
(G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_DATA_QUEUE,GstDataQueue))
#define GST_DATA_QUEUE_CLASS(klass) \
(G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_DATA_QUEUE,GstDataQueueClass))
#define GST_IS_DATA_QUEUE(obj) \
(G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_DATA_QUEUE))
#define GST_IS_DATA_QUEUE_CLASS(klass) \
(G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_DATA_QUEUE))
typedef struct _GstDataQueue GstDataQueue;
typedef struct _GstDataQueueClass GstDataQueueClass;
typedef struct _GstDataQueueSize GstDataQueueSize;
typedef struct _GstDataQueueItem GstDataQueueItem;
typedef struct _GstDataQueuePrivate GstDataQueuePrivate;
/**
* GstDataQueueItem:
* @object: the #GstMiniObject to queue.
* @size: the size in bytes of the miniobject.
* @duration: the duration in #GstClockTime of the miniobject. Can not be
* #GST_CLOCK_TIME_NONE.
* @visible: #TRUE if @object should be considered as a visible object.
* @destroy: The #GDestroyNotify function to use to free the #GstDataQueueItem.
* This function should also drop the reference to @object the owner of the
* #GstDataQueueItem is assumed to hold.
*
* Structure used by #GstDataQueue. You can supply a different structure, as
* long as the top of the structure is identical to this structure.
*/
struct _GstDataQueueItem
{
GstMiniObject *object;
guint size;
guint64 duration;
gboolean visible;
/* user supplied destroy function */
GDestroyNotify destroy;
/* < private > */
gpointer _gst_reserved[GST_PADDING];
};
/**
* GstDataQueueSize:
* @visible: number of buffers
* @bytes: number of bytes
* @time: amount of time
*
* Structure describing the size of a queue.
*/
struct _GstDataQueueSize
{
guint visible;
guint bytes;
guint64 time;
};
/**
* GstDataQueueCheckFullFunction:
* @queue: a #GstDataQueue.
* @visible: The number of visible items currently in the queue.
* @bytes: The amount of bytes currently in the queue.
* @time: The accumulated duration of the items currently in the queue.
* @checkdata: The #gpointer registered when the #GstDataQueue was created.
*
* The prototype of the function used to inform the queue that it should be
* considered as full.
*
* Returns: #TRUE if the queue should be considered full.
*/
typedef gboolean (*GstDataQueueCheckFullFunction) (GstDataQueue * queue,
guint visible, guint bytes, guint64 time, gpointer checkdata);
typedef void (*GstDataQueueFullCallback) (GstDataQueue * queue, gpointer checkdata);
typedef void (*GstDataQueueEmptyCallback) (GstDataQueue * queue, gpointer checkdata);
/**
* GstDataQueue:
* @object: the parent structure
*
* Opaque #GstDataQueue structure.
*/
struct _GstDataQueue
{
GObject object;
/*< private >*/
GstDataQueuePrivate *priv;
gpointer _gst_reserved[GST_PADDING];
};
struct _GstDataQueueClass
{
GObjectClass parent_class;
/* signals */
void (*empty) (GstDataQueue * queue);
void (*full) (GstDataQueue * queue);
gpointer _gst_reserved[GST_PADDING];
};
GType gst_data_queue_get_type (void);
GstDataQueue * gst_data_queue_new (GstDataQueueCheckFullFunction checkfull,
GstDataQueueFullCallback fullcallback,
GstDataQueueEmptyCallback emptycallback,
gpointer checkdata) G_GNUC_MALLOC;
gboolean gst_data_queue_push (GstDataQueue * queue, GstDataQueueItem * item);
gboolean gst_data_queue_push_force (GstDataQueue * queue, GstDataQueueItem * item);
gboolean gst_data_queue_pop (GstDataQueue * queue, GstDataQueueItem ** item);
gboolean gst_data_queue_peek (GstDataQueue * queue, GstDataQueueItem ** item);
void gst_data_queue_flush (GstDataQueue * queue);
void gst_data_queue_set_flushing (GstDataQueue * queue, gboolean flushing);
gboolean gst_data_queue_drop_head (GstDataQueue * queue, GType type);
gboolean gst_data_queue_is_full (GstDataQueue * queue);
gboolean gst_data_queue_is_empty (GstDataQueue * queue);
void gst_data_queue_get_level (GstDataQueue * queue, GstDataQueueSize *level);
void gst_data_queue_limits_changed (GstDataQueue * queue);
G_END_DECLS
#endif /* __GST_DATA_QUEUE_H__ */