gstreamer/gst/rtp/gstrtpstorage.c
2021-03-29 12:45:22 +02:00

221 lines
7.2 KiB
C

/* GStreamer plugin for forward error correction
* Copyright (C) 2017 Pexip
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* Author: Mikhail Fludkov <misha@pexip.com>
*/
/**
* SECTION:element-rtpstorage
* @short_description: RTP storage for forward error correction (FEC) in rtpbin
* @title: rtpstorage
*
* Helper element for storing packets to aid later packet recovery from packet
* loss using RED/FEC (Forward Error Correction).
*
* The purpose of this element is to store a moving window of packets which
* downstream elements such as #GstRtpUlpFecDec can request in order to perform
* recovery of lost packets upon receiving custom GstRtpPacketLost events,
* usually from #GstRtpJitterBuffer.
*
* As such, when building a pipeline manually, it should have the form:
*
* ```
* rtpstorage ! rtpjitterbuffer ! rtpulpfecdec
* ```
*
* where rtpulpfecdec get passed a reference to the object pointed to by
* the #GstRtpStorage:internal-storage property.
*
* The #GstRtpStorage:size-time property should be configured with a value
* equal to the #GstRtpJitterBuffer latency, plus some tolerance, in the order
* of milliseconds, for example in the example found at
* <https://github.com/sdroege/gstreamer-rs/blob/master/examples/src/bin/rtpfecclient.rs>,
* `size-time` is configured as 200 + 50 milliseconds (latency + tolerance).
*
* When using #GstRtpBin, a storage element is created automatically, and
* can be configured upon receiving the #GstRtpBin::new-storage signal.
*
* See also: #GstRtpBin, #GstRtpUlpFecDec
* Since: 1.14
*/
#include "gstrtpelements.h"
#include "gstrtpstorage.h"
static GstStaticPadTemplate sinktemplate = GST_STATIC_PAD_TEMPLATE ("sink",
GST_PAD_SINK,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("application/x-rtp")
);
static GstStaticPadTemplate srctemplate = GST_STATIC_PAD_TEMPLATE ("src",
GST_PAD_SRC,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("application/x-rtp")
);
enum
{
PROP_0,
PROP_SIZE_TIME,
PROP_INTERNAL_STORAGE,
N_PROPERTIES
};
static GParamSpec *klass_properties[N_PROPERTIES] = { NULL, };
#define DEFAULT_SIZE_TIME (0)
GST_DEBUG_CATEGORY (gst_rtp_storage_debug);
#define GST_CAT_DEFAULT (gst_rtp_storage_debug)
G_DEFINE_TYPE (GstRtpStorage, gst_rtp_storage, GST_TYPE_ELEMENT);
GST_ELEMENT_REGISTER_DEFINE_WITH_CODE (rtpstorage, "rtpstorage", GST_RANK_NONE,
GST_TYPE_RTP_STORAGE, rtp_element_init (plugin));
static GstFlowReturn
gst_rtp_storage_chain (GstPad * pad, GstObject * parent, GstBuffer * buf)
{
GstRtpStorage *self = GST_RTP_STORAGE (parent);;
if (rtp_storage_append_buffer (self->storage, buf))
return gst_pad_push (self->srcpad, buf);
return GST_FLOW_OK;
}
static void
gst_rtp_storage_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec)
{
GstRtpStorage *self = GST_RTP_STORAGE (object);
switch (prop_id) {
case PROP_SIZE_TIME:
GST_DEBUG_OBJECT (self, "RTP storage size set to %" GST_TIME_FORMAT,
GST_TIME_ARGS (g_value_get_uint64 (value)));
rtp_storage_set_size (self->storage, g_value_get_uint64 (value));
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gst_rtp_storage_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec)
{
GstRtpStorage *self = GST_RTP_STORAGE (object);
switch (prop_id) {
case PROP_SIZE_TIME:
g_value_set_uint64 (value, rtp_storage_get_size (self->storage));
break;
case PROP_INTERNAL_STORAGE:
{
g_value_set_object (value, self->storage);
break;
}
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static gboolean
gst_rtp_storage_src_query (GstPad * pad, GstObject * parent, GstQuery * query)
{
GstRtpStorage *self = GST_RTP_STORAGE (parent);
if (GST_QUERY_TYPE (query) == GST_QUERY_CUSTOM) {
GstStructure *s = gst_query_writable_structure (query);
if (gst_structure_has_name (s, "GstRtpStorage")) {
gst_structure_set (s, "storage", G_TYPE_OBJECT, self->storage, NULL);
return TRUE;
}
}
return gst_pad_query_default (pad, parent, query);
}
static void
gst_rtp_storage_init (GstRtpStorage * self)
{
self->srcpad = gst_pad_new_from_static_template (&srctemplate, "src");
self->sinkpad = gst_pad_new_from_static_template (&sinktemplate, "sink");
GST_PAD_SET_PROXY_CAPS (self->sinkpad);
GST_PAD_SET_PROXY_ALLOCATION (self->sinkpad);
gst_pad_set_chain_function (self->sinkpad, gst_rtp_storage_chain);
gst_pad_set_query_function (self->srcpad, gst_rtp_storage_src_query);
gst_element_add_pad (GST_ELEMENT (self), self->srcpad);
gst_element_add_pad (GST_ELEMENT (self), self->sinkpad);
self->storage = rtp_storage_new ();
}
static void
gst_rtp_storage_dispose (GObject * obj)
{
GstRtpStorage *self = GST_RTP_STORAGE (obj);
g_object_unref (self->storage);
G_OBJECT_CLASS (gst_rtp_storage_parent_class)->dispose (obj);
}
static void
gst_rtp_storage_class_init (GstRtpStorageClass * klass)
{
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
GST_DEBUG_CATEGORY_INIT (gst_rtp_storage_debug,
"rtpstorage", 0, "RTP Storage");
GST_DEBUG_REGISTER_FUNCPTR (gst_rtp_storage_chain);
gst_element_class_add_pad_template (element_class,
gst_static_pad_template_get (&srctemplate));
gst_element_class_add_pad_template (element_class,
gst_static_pad_template_get (&sinktemplate));
gst_element_class_set_static_metadata (element_class,
"RTP storage",
"Analyzer/RTP",
"Helper element for various purposes "
"(ex. recovering from packet loss using RED/FEC). "
"Saves given number of RTP packets. "
"Should be instantiated before jitterbuffer",
"Mikhail Fludkov <misha@pexip.com>");
gobject_class->set_property = gst_rtp_storage_set_property;
gobject_class->get_property = gst_rtp_storage_get_property;
gobject_class->dispose = gst_rtp_storage_dispose;
klass_properties[PROP_SIZE_TIME] =
g_param_spec_uint64 ("size-time", "Storage size (in ns)",
"The amount of data to keep in the storage (in ns, 0-disable)", 0,
G_MAXUINT64, DEFAULT_SIZE_TIME,
G_PARAM_READWRITE | G_PARAM_CONSTRUCT | G_PARAM_STATIC_STRINGS);
klass_properties[PROP_INTERNAL_STORAGE] =
g_param_spec_object ("internal-storage", "Internal storage",
"Internal RtpStorage object", G_TYPE_OBJECT,
G_PARAM_READABLE | G_PARAM_STATIC_STRINGS);
g_object_class_install_properties (gobject_class, N_PROPERTIES,
klass_properties);
}