gstreamer/gst/rist/gstristrtxreceive.c
2021-04-11 16:16:55 +00:00

304 lines
9 KiB
C

/* RTP Retransmission receiver element for GStreamer
*
* gstrtprtxreceive.c:
*
* Copyright (C) 2013-2019 Collabora Ltd.
* @author Julien Isorce <julien.isorce@collabora.co.uk>
* 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-ristrtxreceive
* @title: ristrtxreceive
* @see_also: ristrtxsend
*
* This element translates RIST RTX packets into its original form with the
* %GST_RTP_BUFFER_FLAG_RETRANSMISSION flag set. This element is intented to
* be used by ristsrc element.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <gst/gst.h>
#include <gst/rtp/gstrtpbuffer.h>
#include "gstrist.h"
GST_DEBUG_CATEGORY_STATIC (gst_rist_rtx_receive_debug);
#define GST_CAT_DEFAULT gst_rist_rtx_receive_debug
enum
{
PROP_0,
PROP_NUM_RTX_REQUESTS,
PROP_NUM_RTX_PACKETS,
PROP_RIST
};
static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src",
GST_PAD_SRC,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("application/x-rtp")
);
static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",
GST_PAD_SINK,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("application/x-rtp")
);
struct _GstRistRtxReceive
{
GstElement element;
/* pad */
GstPad *sinkpad;
GstPad *srcpad;
/* statistics */
guint num_rtx_requests;
guint num_rtx_packets;
GstClockTime last_time;
};
static gboolean gst_rist_rtx_receive_src_event (GstPad * pad,
GstObject * parent, GstEvent * event);
static GstFlowReturn gst_rist_rtx_receive_chain (GstPad * pad,
GstObject * parent, GstBuffer * buffer);
static GstStateChangeReturn gst_rist_rtx_receive_change_state (GstElement *
element, GstStateChange transition);
static void gst_rist_rtx_receive_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec);
G_DEFINE_TYPE_WITH_CODE (GstRistRtxReceive, gst_rist_rtx_receive,
GST_TYPE_ELEMENT, GST_DEBUG_CATEGORY_INIT (gst_rist_rtx_receive_debug,
"ristrtxreceive", 0, "RIST retransmission receiver"));
GST_ELEMENT_REGISTER_DEFINE (ristrtxreceive, "ristrtxreceive",
GST_RANK_NONE, GST_TYPE_RIST_RTX_RECEIVE);
static void
gst_rist_rtx_receive_class_init (GstRistRtxReceiveClass * klass)
{
GObjectClass *gobject_class;
GstElementClass *gstelement_class;
gobject_class = (GObjectClass *) klass;
gstelement_class = (GstElementClass *) klass;
gobject_class->get_property = gst_rist_rtx_receive_get_property;
g_object_class_install_property (gobject_class, PROP_NUM_RTX_REQUESTS,
g_param_spec_uint ("num-rtx-requests", "Num RTX Requests",
"Number of retransmission events received", 0, G_MAXUINT,
0, G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class, PROP_NUM_RTX_PACKETS,
g_param_spec_uint ("num-rtx-packets", "Num RTX Packets",
" Number of retransmission packets received", 0, G_MAXUINT,
0, G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
gst_element_class_add_static_pad_template (gstelement_class, &src_factory);
gst_element_class_add_static_pad_template (gstelement_class, &sink_factory);
gst_element_class_set_static_metadata (gstelement_class,
"RIST Retransmission receiver", "Codec",
"Receive retransmitted RIST packets according to VSF TR-06-1",
"Nicolas Dufresne <nicolas.dufresne@collabora.com>");
gstelement_class->change_state =
GST_DEBUG_FUNCPTR (gst_rist_rtx_receive_change_state);
}
static void
gst_rist_rtx_receive_reset (GstRistRtxReceive * rtx)
{
GST_OBJECT_LOCK (rtx);
rtx->num_rtx_requests = 0;
rtx->num_rtx_packets = 0;
GST_OBJECT_UNLOCK (rtx);
}
static void
gst_rist_rtx_receive_init (GstRistRtxReceive * rtx)
{
GstElementClass *klass = GST_ELEMENT_GET_CLASS (rtx);
rtx->srcpad =
gst_pad_new_from_template (gst_element_class_get_pad_template (klass,
"src"), "src");
GST_PAD_SET_PROXY_CAPS (rtx->srcpad);
GST_PAD_SET_PROXY_ALLOCATION (rtx->srcpad);
gst_pad_set_event_function (rtx->srcpad,
GST_DEBUG_FUNCPTR (gst_rist_rtx_receive_src_event));
gst_element_add_pad (GST_ELEMENT (rtx), rtx->srcpad);
rtx->sinkpad =
gst_pad_new_from_template (gst_element_class_get_pad_template (klass,
"sink"), "sink");
GST_PAD_SET_PROXY_CAPS (rtx->sinkpad);
GST_PAD_SET_PROXY_ALLOCATION (rtx->sinkpad);
gst_pad_set_chain_function (rtx->sinkpad,
GST_DEBUG_FUNCPTR (gst_rist_rtx_receive_chain));
gst_element_add_pad (GST_ELEMENT (rtx), rtx->sinkpad);
}
static gboolean
gst_rist_rtx_receive_src_event (GstPad * pad, GstObject * parent,
GstEvent * event)
{
GstRistRtxReceive *rtx = GST_RIST_RTX_RECEIVE (parent);
switch (GST_EVENT_TYPE (event)) {
case GST_EVENT_CUSTOM_UPSTREAM:
{
const GstStructure *s = gst_event_get_structure (event);
/* This event usually comes from the downstream gstrtpjitterbuffer */
if (gst_structure_has_name (s, "GstRTPRetransmissionRequest")) {
#ifndef GST_DISABLE_GST_DEBUG
guint seqnum = 0;
guint ssrc = 0;
/* retrieve seqnum of the packet that need to be retransmitted */
if (!gst_structure_get_uint (s, "seqnum", &seqnum))
seqnum = -1;
/* retrieve ssrc of the packet that need to be retransmitted
* it's useful when reconstructing the original packet from the rtx packet */
if (!gst_structure_get_uint (s, "ssrc", &ssrc))
ssrc = -1;
GST_DEBUG_OBJECT (rtx, "got rtx request for seqnum: %u, ssrc: %X",
seqnum, ssrc);
#endif
GST_OBJECT_LOCK (rtx);
/* increase number of seen requests for our statistics */
++rtx->num_rtx_requests;
GST_OBJECT_UNLOCK (rtx);
}
break;
}
default:
break;
}
return gst_pad_event_default (pad, parent, event);
}
static GstFlowReturn
gst_rist_rtx_receive_chain (GstPad * pad, GstObject * parent,
GstBuffer * buffer)
{
GstRistRtxReceive *rtx = GST_RIST_RTX_RECEIVE (parent);
GstRTPBuffer rtp = GST_RTP_BUFFER_INIT;
guint32 ssrc = 0;
guint16 seqnum = 0;
gboolean is_rtx;
/* map current rtp packet to parse its header */
if (!gst_rtp_buffer_map (buffer, GST_MAP_READ, &rtp))
goto invalid_buffer;
ssrc = gst_rtp_buffer_get_ssrc (&rtp);
seqnum = gst_rtp_buffer_get_seq (&rtp);
/* check if we have a retransmission packet (this information comes from SDP) */
GST_OBJECT_LOCK (rtx);
/* RIST sets SSRC LSB to 1 to indicate an RTC packet */
is_rtx = ssrc & 0x1;
rtx->last_time = GST_BUFFER_PTS (buffer);
if (is_rtx)
/* increase our statistic */
++rtx->num_rtx_packets;
GST_OBJECT_UNLOCK (rtx);
/* create the retransmission packet */
if (is_rtx) {
GST_DEBUG_OBJECT (rtx,
"Recovered packet from RIST RTX seqnum:%u ssrc: %u",
gst_rtp_buffer_get_seq (&rtp), gst_rtp_buffer_get_ssrc (&rtp));
gst_rtp_buffer_set_ssrc (&rtp, ssrc & 0xFFFFFFFE);
GST_BUFFER_FLAG_SET (buffer, GST_RTP_BUFFER_FLAG_RETRANSMISSION);
}
gst_rtp_buffer_unmap (&rtp);
GST_TRACE_OBJECT (rtx, "pushing packet seqnum:%u from master stream "
"ssrc: %X", seqnum, ssrc);
return gst_pad_push (rtx->srcpad, buffer);
invalid_buffer:
{
GST_ELEMENT_WARNING (rtx, STREAM, DECODE, (NULL),
("Received invalid RTP payload, dropping"));
gst_buffer_unref (buffer);
return GST_FLOW_OK;
}
}
static void
gst_rist_rtx_receive_get_property (GObject * object,
guint prop_id, GValue * value, GParamSpec * pspec)
{
GstRistRtxReceive *rtx = GST_RIST_RTX_RECEIVE (object);
switch (prop_id) {
case PROP_NUM_RTX_REQUESTS:
GST_OBJECT_LOCK (rtx);
g_value_set_uint (value, rtx->num_rtx_requests);
GST_OBJECT_UNLOCK (rtx);
break;
case PROP_NUM_RTX_PACKETS:
GST_OBJECT_LOCK (rtx);
g_value_set_uint (value, rtx->num_rtx_packets);
GST_OBJECT_UNLOCK (rtx);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static GstStateChangeReturn
gst_rist_rtx_receive_change_state (GstElement * element,
GstStateChange transition)
{
GstRistRtxReceive *rtx = GST_RIST_RTX_RECEIVE (element);
GstStateChangeReturn ret;
ret =
GST_ELEMENT_CLASS (gst_rist_rtx_receive_parent_class)->change_state
(element, transition);
switch (transition) {
case GST_STATE_CHANGE_PAUSED_TO_READY:
gst_rist_rtx_receive_reset (rtx);
break;
default:
break;
}
return ret;
}