gstreamer/gst/rist/gstroundrobin.c

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/* GStreamer Round Robin
* Copyright (C) 2019 Net Insight AB
* Author: Nicolas Dufresne <nicolas.dufresne@collabora.com>
*
* 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.
*/
/**
* SECTION:element-roundrobin
* @title: roundrobin
*
* This is a generic element that will distribute equally incoming
* buffers over multiple src pads. This is the opposite of tee
* element, which duplicates buffers over all pads. This element
* can be used to distrute load across multiple branches when the buffer
* can be processed indepently.
*/
#include "gstroundrobin.h"
GST_DEBUG_CATEGORY_STATIC (gst_round_robin_debug);
#define GST_CAT_DEFAULT gst_round_robin_debug
static GstStaticPadTemplate sink_templ = GST_STATIC_PAD_TEMPLATE ("sink",
GST_PAD_SINK,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("ANY"));
static GstStaticPadTemplate src_templ = GST_STATIC_PAD_TEMPLATE ("src_%d",
GST_PAD_SRC,
GST_PAD_REQUEST,
GST_STATIC_CAPS ("ANY"));
struct _GstRoundRobin
{
GstElement parent;
gint index;
};
G_DEFINE_TYPE_WITH_CODE (GstRoundRobin, gst_round_robin,
GST_TYPE_ELEMENT, GST_DEBUG_CATEGORY_INIT (gst_round_robin_debug,
"roundrobin", 0, "Round Robin"));
static GstFlowReturn
gst_round_robin_chain (GstPad * pad, GstObject * parent, GstBuffer * buffer)
{
GstRoundRobin *disp = (GstRoundRobin *) parent;
GstElement *elem = (GstElement *) parent;
GstPad *src_pad = NULL;
GstFlowReturn ret;
GST_OBJECT_LOCK (disp);
if (disp->index >= elem->numsrcpads)
disp->index = 0;
src_pad = g_list_nth_data (elem->srcpads, disp->index);
if (src_pad) {
gst_object_ref (src_pad);
disp->index += 1;
}
GST_OBJECT_UNLOCK (disp);
if (!src_pad)
/* no pad, that's fine */
return GST_FLOW_OK;
ret = gst_pad_push (src_pad, buffer);
gst_object_unref (src_pad);
return ret;
}
static GstPad *
gst_round_robin_request_pad (GstElement * element, GstPadTemplate * templ,
const gchar * name, const GstCaps * caps)
{
GstPad *pad;
pad = gst_element_get_static_pad (element, name);
if (pad) {
gst_object_unref (pad);
return NULL;
}
pad = gst_pad_new_from_static_template (&src_templ, name);
gst_element_add_pad (element, pad);
return pad;
}
static void
gst_round_robin_init (GstRoundRobin * disp)
{
GstPad *pad;
gst_element_create_all_pads (GST_ELEMENT (disp));
pad = GST_PAD (GST_ELEMENT (disp)->sinkpads->data);
GST_PAD_SET_PROXY_CAPS (pad);
GST_PAD_SET_PROXY_SCHEDULING (pad);
/* do not proxy allocation, it requires special handling like tee does */
gst_pad_set_chain_function (pad, GST_DEBUG_FUNCPTR (gst_round_robin_chain));
}
static void
gst_round_robin_class_init (GstRoundRobinClass * klass)
{
GstElementClass *element_class = (GstElementClass *) klass;
gst_element_class_set_metadata (element_class,
"Round Robin", "Source/Network",
"A round robin dispatcher element.",
"Nicolas Dufresne <nicolas.dufresne@collabora.com");
gst_element_class_add_static_pad_template (element_class, &sink_templ);
gst_element_class_add_static_pad_template (element_class, &src_templ);
element_class->request_new_pad =
GST_DEBUG_FUNCPTR (gst_round_robin_request_pad);
}