1 /* GStreamer plugin for forward error correction
2 * Copyright (C) 2017 Pexip
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with this library; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
18 * Author: Mikhail Fludkov <misha@pexip.com>
22 * SECTION:element-rtpstorage
23 * @short_description: RTP storage for forward error correction (FEC) in rtpbin
26 * Helper element for storing packets to aid later packet recovery from packet
27 * loss using RED/FEC (Forward Error Correction).
29 * The purpose of this element is to store a moving window of packets which
30 * downstream elements such as #GstRtpUlpFecDec can request in order to perform
31 * recovery of lost packets upon receiving custom GstRtpPacketLost events,
32 * usually from #GstRtpJitterBuffer.
34 * As such, when building a pipeline manually, it should have the form:
37 * rtpstorage ! rtpjitterbuffer ! rtpulpfecdec
40 * where rtpulpfecdec get passed a reference to the object pointed to by
41 * the #GstRtpStorage:internal-storage property.
43 * The #GstRtpStorage:size-time property should be configured with a value
44 * equal to the #GstRtpJitterBuffer latency, plus some tolerance, in the order
45 * of milliseconds, for example in the example found at
46 * <https://github.com/sdroege/gstreamer-rs/blob/master/examples/src/bin/rtpfecclient.rs>,
47 * `size-time` is configured as 200 + 50 milliseconds (latency + tolerance).
49 * When using #GstRtpBin, a storage element is created automatically, and
50 * can be configured upon receiving the #GstRtpBin::new-storage signal.
52 * See also: #GstRtpBin, #GstRtpUlpFecDec
56 #include "gstrtpstorage.h"
58 static GstStaticPadTemplate sinktemplate = GST_STATIC_PAD_TEMPLATE ("sink",
61 GST_STATIC_CAPS ("application/x-rtp")
64 static GstStaticPadTemplate srctemplate = GST_STATIC_PAD_TEMPLATE ("src",
67 GST_STATIC_CAPS ("application/x-rtp")
74 PROP_INTERNAL_STORAGE,
78 static GParamSpec *klass_properties[N_PROPERTIES] = { NULL, };
80 #define DEFAULT_SIZE_TIME (0)
82 GST_DEBUG_CATEGORY (gst_rtp_storage_debug);
83 #define GST_CAT_DEFAULT (gst_rtp_storage_debug)
85 G_DEFINE_TYPE (GstRtpStorage, gst_rtp_storage, GST_TYPE_ELEMENT);
88 gst_rtp_storage_chain (GstPad * pad, GstObject * parent, GstBuffer * buf)
90 GstRtpStorage *self = GST_RTP_STORAGE (parent);;
92 if (rtp_storage_append_buffer (self->storage, buf))
93 return gst_pad_push (self->srcpad, buf);
98 gst_rtp_storage_set_property (GObject * object, guint prop_id,
99 const GValue * value, GParamSpec * pspec)
101 GstRtpStorage *self = GST_RTP_STORAGE (object);
105 GST_DEBUG_OBJECT (self, "RTP storage size set to %" GST_TIME_FORMAT,
106 GST_TIME_ARGS (g_value_get_uint64 (value)));
107 rtp_storage_set_size (self->storage, g_value_get_uint64 (value));
110 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
116 gst_rtp_storage_get_property (GObject * object, guint prop_id,
117 GValue * value, GParamSpec * pspec)
119 GstRtpStorage *self = GST_RTP_STORAGE (object);
122 g_value_set_uint64 (value, rtp_storage_get_size (self->storage));
124 case PROP_INTERNAL_STORAGE:
126 g_value_set_object (value, self->storage);
130 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
136 gst_rtp_storage_init (GstRtpStorage * self)
138 self->srcpad = gst_pad_new_from_static_template (&srctemplate, "src");
139 self->sinkpad = gst_pad_new_from_static_template (&sinktemplate, "sink");
140 GST_PAD_SET_PROXY_CAPS (self->sinkpad);
141 GST_PAD_SET_PROXY_ALLOCATION (self->sinkpad);
142 gst_pad_set_chain_function (self->sinkpad, gst_rtp_storage_chain);
144 gst_element_add_pad (GST_ELEMENT (self), self->srcpad);
145 gst_element_add_pad (GST_ELEMENT (self), self->sinkpad);
147 self->storage = rtp_storage_new ();
151 gst_rtp_storage_dispose (GObject * obj)
153 GstRtpStorage *self = GST_RTP_STORAGE (obj);
154 g_object_unref (self->storage);
155 G_OBJECT_CLASS (gst_rtp_storage_parent_class)->dispose (obj);
159 gst_rtp_storage_class_init (GstRtpStorageClass * klass)
161 GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
162 GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
164 GST_DEBUG_CATEGORY_INIT (gst_rtp_storage_debug,
165 "rtpstorage", 0, "RTP Storage");
166 GST_DEBUG_REGISTER_FUNCPTR (gst_rtp_storage_chain);
168 gst_element_class_add_pad_template (element_class,
169 gst_static_pad_template_get (&srctemplate));
170 gst_element_class_add_pad_template (element_class,
171 gst_static_pad_template_get (&sinktemplate));
173 gst_element_class_set_static_metadata (element_class,
176 "Helper element for various purposes "
177 "(ex. recovering from packet loss using RED/FEC). "
178 "Saves given number of RTP packets. "
179 "Should be instantiated before jitterbuffer",
180 "Mikhail Fludkov <misha@pexip.com>");
182 gobject_class->set_property = gst_rtp_storage_set_property;
183 gobject_class->get_property = gst_rtp_storage_get_property;
184 gobject_class->dispose = gst_rtp_storage_dispose;
186 klass_properties[PROP_SIZE_TIME] =
187 g_param_spec_uint64 ("size-time", "Storage size (in ns)",
188 "The amount of data to keep in the storage (in ns, 0-disable)", 0,
189 G_MAXUINT64, DEFAULT_SIZE_TIME,
190 G_PARAM_READWRITE | G_PARAM_CONSTRUCT | G_PARAM_STATIC_STRINGS);
192 klass_properties[PROP_INTERNAL_STORAGE] =
193 g_param_spec_object ("internal-storage", "Internal storage",
194 "Internal RtpStorage object", G_TYPE_OBJECT,
195 G_PARAM_READABLE | G_PARAM_STATIC_STRINGS);
197 g_object_class_install_properties (gobject_class, N_PROPERTIES,