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/* GStreamer
* Copyright (C) <2020> Matthew Waters <matthew@centricular.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., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/**
* SECTION:rtphdrexttwcc
* @title: GstRtphdrext-TWCC
* @short_description: Helper methods for dealing with RTP header extensions
* in the Audio/Video RTP Profile for transport-wide-cc
* @see_also: #GstRTPHeaderExtension, #GstRTPBasePayload, #GstRTPBaseDepayload, gstrtpbuffer
*
* Since: 1.20
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <gst/rtp/gstrtpbuffer.h>
#include "gstrtphdrext-twcc.h"
GST_DEBUG_CATEGORY_STATIC (rtphdrext_twcc_debug);
#define GST_CAT_DEFAULT (rtphdrext_twcc_debug)
#define gst_gl_base_filter_parent_class parent_class
G_DEFINE_TYPE_WITH_CODE (GstRTPHeaderExtensionTWCC,
gst_rtp_header_extension_twcc, GST_TYPE_RTP_HEADER_EXTENSION,
GST_DEBUG_CATEGORY_INIT (GST_CAT_DEFAULT, "rtphdrexttwcc", 0,
"RTP TWCC Header Extensions");
);
GST_ELEMENT_REGISTER_DEFINE (rtphdrexttwcc, "rtphdrexttwcc", GST_RANK_MARGINAL,
GST_TYPE_RTP_HEADER_EXTENSION_TWCC);
#define TWCC_EXTMAP_STR "http://www.ietf.org/id/draft-holmer-rmcat-transport-wide-cc-extensions-01"
static void gst_rtp_header_extension_twcc_set_property (GObject * object,
guint prop_id, const GValue * value, GParamSpec * pspec);
static void gst_rtp_header_extension_twcc_get_property (GObject * object,
guint prop_id, GValue * value, GParamSpec * pspec);
static GstRTPHeaderExtensionFlags
gst_rtp_header_extension_twcc_get_supported_flags (GstRTPHeaderExtension * ext);
static gsize gst_rtp_header_extension_twcc_get_max_size (GstRTPHeaderExtension *
ext, const GstBuffer * buffer);
static gssize gst_rtp_header_extension_twcc_write (GstRTPHeaderExtension * ext,
const GstBuffer * input_meta, GstRTPHeaderExtensionFlags write_flags,
GstBuffer * output, guint8 * data, gsize size);
static gboolean gst_rtp_header_extension_twcc_read (GstRTPHeaderExtension * ext,
GstRTPHeaderExtensionFlags read_flags, const guint8 * data, gsize size,
GstBuffer * buffer);
enum
{
PROP_0,
PROP_N_STREAMS,
};
static void
gst_rtp_header_extension_twcc_class_init (GstRTPHeaderExtensionTWCCClass *
klass)
{
GstRTPHeaderExtensionClass *rtp_hdr_class;
GstElementClass *gstelement_class;
GObjectClass *gobject_class;
rtp_hdr_class = (GstRTPHeaderExtensionClass *) klass;
gobject_class = (GObjectClass *) klass;
gstelement_class = (GstElementClass *) klass;
gobject_class->set_property = gst_rtp_header_extension_twcc_set_property;
gobject_class->get_property = gst_rtp_header_extension_twcc_get_property;
/**
* rtphdrexttwcc:n-streams:
*
* The number of independant RTP streams that are being used for the transport
* wide counter for TWCC. If set to 1 (the default), then any existing
* transport wide counter is kept.
*
* Since: 1.20
*/
g_object_class_install_property (gobject_class, PROP_N_STREAMS,
g_param_spec_uint ("n-streams", "N Streams",
"The number of separate RTP streams this header applies to",
1, G_MAXUINT32, 1, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
rtp_hdr_class->get_supported_flags =
gst_rtp_header_extension_twcc_get_supported_flags;
rtp_hdr_class->get_max_size = gst_rtp_header_extension_twcc_get_max_size;
rtp_hdr_class->write = gst_rtp_header_extension_twcc_write;
rtp_hdr_class->read = gst_rtp_header_extension_twcc_read;
rtp_hdr_class->set_attributes_from_caps =
gst_rtp_header_extension_set_attributes_from_caps_simple_sdp;
rtp_hdr_class->set_caps_from_attributes =
gst_rtp_header_extension_set_caps_from_attributes_simple_sdp;
gst_element_class_set_static_metadata (gstelement_class,
"Transport Wide Congestion Control", GST_RTP_HDREXT_ELEMENT_CLASS,
"Extends RTP packets to add sequence number transport wide.",
"Matthew Waters <matthew@centricular.com>");
gst_rtp_header_extension_class_set_uri (rtp_hdr_class, TWCC_EXTMAP_STR);
}
static void
gst_rtp_header_extension_twcc_init (GstRTPHeaderExtensionTWCC * twcc)
{
twcc->n_streams = 1;
}
static void
gst_rtp_header_extension_twcc_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec)
{
GstRTPHeaderExtensionTWCC *twcc = GST_RTP_HEADER_EXTENSION_TWCC (object);
switch (prop_id) {
case PROP_N_STREAMS:
twcc->n_streams = g_value_get_uint (value);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gst_rtp_header_extension_twcc_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec)
{
GstRTPHeaderExtensionTWCC *twcc = GST_RTP_HEADER_EXTENSION_TWCC (object);
switch (prop_id) {
case PROP_N_STREAMS:
g_value_set_uint (value, twcc->n_streams);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static GstRTPHeaderExtensionFlags
gst_rtp_header_extension_twcc_get_supported_flags (GstRTPHeaderExtension * ext)
{
return GST_RTP_HEADER_EXTENSION_ONE_BYTE;
}
static gsize
gst_rtp_header_extension_twcc_get_max_size (GstRTPHeaderExtension * ext,
const GstBuffer * buffer)
{
return 2;
}
static gssize
gst_rtp_header_extension_twcc_write (GstRTPHeaderExtension * ext,
const GstBuffer * input_meta, GstRTPHeaderExtensionFlags write_flags,
GstBuffer * output, guint8 * data, gsize size)
{
GstRTPHeaderExtensionTWCC *twcc = GST_RTP_HEADER_EXTENSION_TWCC (ext);
GstRTPBuffer rtp = { NULL, };
gpointer ext_data;
guint ext_size;
gsize written = 0;
g_return_val_if_fail (size >= gst_rtp_header_extension_twcc_get_max_size (ext,
NULL), -1);
g_return_val_if_fail (write_flags &
gst_rtp_header_extension_twcc_get_supported_flags (ext), -1);
if (!gst_rtp_buffer_map (output, GST_MAP_READWRITE, &rtp))
goto map_failed;
/* if there already is a twcc-seqnum inside the packet */
if (gst_rtp_buffer_get_extension_onebyte_header (&rtp,
gst_rtp_header_extension_get_id (ext), 0, &ext_data, &ext_size)) {
if (ext_size < gst_rtp_header_extension_twcc_get_max_size (ext, NULL))
goto existing_too_small;
/* with only one stream, we read the twcc-seqnum */
if (twcc->n_streams == 1)
twcc->seqnum = GST_READ_UINT16_BE (ext_data);
} else {
/* with only one stream, we read the existing seqnum */
if (twcc->n_streams == 1)
twcc->seqnum = gst_rtp_buffer_get_seq (&rtp);
written = 2;
}
GST_WRITE_UINT16_BE (data, twcc->seqnum);
gst_rtp_buffer_unmap (&rtp);
twcc->seqnum++;
return written;
/* ERRORS */
map_failed:
{
GST_ERROR ("failed to map buffer %p", output);
return -1;
}
existing_too_small:
{
GST_ERROR ("Cannot rewrite twcc data of smaller size (%u)", ext_size);
return 0;
}
}
static gboolean
gst_rtp_header_extension_twcc_read (GstRTPHeaderExtension * ext,
GstRTPHeaderExtensionFlags read_flags, const guint8 * data, gsize size,
GstBuffer * buffer)
{
/* TODO: does this need an extra GstMeta? */
return TRUE;
}
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