gstreamer/gst/pcapparse/gstirtspparse.c
2021-04-11 16:16:55 +00:00

298 lines
9 KiB
C

/* GStreamer Interleaved RTSP parser
* Copyright (C) 2011 Mark Nauwelaerts <mark.nauwelaerts@collabora.co.uk>
* Copyright (C) 2011 Nokia Corporation. All rights reserved.
* Contact: Stefan Kost <stefan.kost@nokia.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-irtspparse
* @title: irtspparse
* @short_description: Interleaved RTSP parser
* @see_also: #GstPcapParse
*
* This is an interleaved RTSP parser that allows extracting specific
* so-called "channels" from received interleaved (TCP) RTSP data
* (typically extracted from some network capture).
*
* ## Example launch line
* |[
* gst-launch-1.0 filesrc location=h264crasher.pcap ! pcapparse ! irtspparse
* ! rtph264depay ! ffdec_h264 ! fakesink
* ]| Read from a pcap dump file using filesrc, extract the raw TCP packets,
* depayload and decode them.
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <string.h>
#include "gstirtspparse.h"
#include <gst/base/gstbytereader.h>
GST_DEBUG_CATEGORY_STATIC (irtsp_parse_debug);
#define GST_CAT_DEFAULT irtsp_parse_debug
enum
{
PROP_0,
PROP_CHANNEL_ID
};
static GstStaticPadTemplate src_template = GST_STATIC_PAD_TEMPLATE ("src",
GST_PAD_SRC,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("application/x-rtp ; application/x-rtcp"));
static GstStaticPadTemplate sink_template = GST_STATIC_PAD_TEMPLATE ("sink",
GST_PAD_SINK,
GST_PAD_ALWAYS,
GST_STATIC_CAPS_ANY);
static void gst_irtsp_parse_finalize (GObject * object);
static gboolean gst_irtsp_parse_start (GstBaseParse * parse);
static gboolean gst_irtsp_parse_stop (GstBaseParse * parse);
static GstFlowReturn gst_irtsp_parse_handle_frame (GstBaseParse * parse,
GstBaseParseFrame * frame, gint * skipsize);
static void gst_irtsp_parse_set_property (GObject * object,
guint prop_id, const GValue * value, GParamSpec * pspec);
static void gst_irtsp_parse_get_property (GObject * object,
guint prop_id, GValue * value, GParamSpec * pspec);
#define parent_class gst_irtsp_parse_parent_class
G_DEFINE_TYPE (GstIRTSPParse, gst_irtsp_parse, GST_TYPE_BASE_PARSE);
GST_ELEMENT_REGISTER_DEFINE (irtspparse, "irtspparse", GST_RANK_NONE,
GST_TYPE_IRTSP_PARSE);
static void
gst_irtsp_parse_class_init (GstIRTSPParseClass * klass)
{
GstBaseParseClass *parse_class = GST_BASE_PARSE_CLASS (klass);
GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
GObjectClass *object_class = G_OBJECT_CLASS (klass);
GST_DEBUG_CATEGORY_INIT (irtsp_parse_debug, "irtspparse", 0,
"Interleaved RTSP stream parser");
object_class->finalize = gst_irtsp_parse_finalize;
object_class->set_property = gst_irtsp_parse_set_property;
object_class->get_property = gst_irtsp_parse_get_property;
g_object_class_install_property (object_class, PROP_CHANNEL_ID,
g_param_spec_int ("channel-id", "channel-id",
"Channel Identifier", 0, 255,
0, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
parse_class->start = GST_DEBUG_FUNCPTR (gst_irtsp_parse_start);
parse_class->stop = GST_DEBUG_FUNCPTR (gst_irtsp_parse_stop);
parse_class->handle_frame = GST_DEBUG_FUNCPTR (gst_irtsp_parse_handle_frame);
gst_element_class_add_static_pad_template (element_class, &sink_template);
gst_element_class_add_static_pad_template (element_class, &src_template);
gst_element_class_set_static_metadata (element_class, "IRTSPParse",
"Raw/Parser",
"Parses a raw interleaved RTSP stream",
"Mark Nauwelaerts <mark.nauwelaerts@collabora.co.uk>");
}
static void
gst_irtsp_parse_reset (GstIRTSPParse * IRTSPParse)
{
IRTSPParse->state = IRTSP_SEARCH_FRAME;
IRTSPParse->current_offset = 0;
IRTSPParse->discont = FALSE;
}
static void
gst_irtsp_parse_init (GstIRTSPParse * IRTSPParse)
{
gst_base_parse_set_min_frame_size (GST_BASE_PARSE (IRTSPParse), 1);
gst_irtsp_parse_reset (IRTSPParse);
}
static void
gst_irtsp_parse_finalize (GObject * object)
{
G_OBJECT_CLASS (parent_class)->finalize (object);
}
static gboolean
gst_irtsp_parse_start (GstBaseParse * parse)
{
GstIRTSPParse *IRTSPParse = GST_IRTSP_PARSE (parse);
GST_DEBUG_OBJECT (parse, "starting");
gst_irtsp_parse_reset (IRTSPParse);
return TRUE;
}
static gboolean
gst_irtsp_parse_stop (GstBaseParse * parse)
{
GST_DEBUG_OBJECT (parse, "stopping");
return TRUE;
}
static void
gst_irtsp_set_caps_once (GstBaseParse * parse)
{
if (!gst_pad_has_current_caps (GST_BASE_PARSE_SRC_PAD (parse))) {
GstCaps *caps = gst_caps_new_empty_simple ("application/x-rtp");
gst_pad_set_caps (GST_BASE_PARSE_SRC_PAD (parse), caps);
gst_caps_unref (caps);
}
}
static GstFlowReturn
gst_irtsp_parse_handle_frame (GstBaseParse * parse,
GstBaseParseFrame * frame, gint * skipsize)
{
static const guint frame_header_size = sizeof (guint8) * 4;
static const guint8 frame_header_magic = 0x24;
GstIRTSPParse *IRTSPParse = GST_IRTSP_PARSE (parse);
GstBuffer *buf = frame->buffer;
GstMapInfo map;
const guint8 *frame_start;
guint8 current_channel_id;
const guint8 *data;
guint data_size;
guint flushed_size;
if (G_UNLIKELY (GST_BUFFER_FLAG_IS_SET (frame->buffer,
GST_BUFFER_FLAG_DISCONT))) {
IRTSPParse->discont = TRUE;
}
gst_buffer_map (buf, &map, GST_MAP_READ);
start:
g_assert (map.size >= IRTSPParse->current_offset);
data = &map.data[IRTSPParse->current_offset];
data_size = map.size - IRTSPParse->current_offset;
switch (IRTSPParse->state) {
case IRTSP_SEARCH_FRAME:
/* Use the first occurrence of 0x24 as a start of interleaved frames.
* This 'trick' allows us to parse a dump that doesn't contain RTSP
* handshake. It's up to user to provide the data where the first 0x24
* is an RTSP frame */
frame_start = memchr (data, frame_header_magic, data_size);
if (frame_start) {
IRTSPParse->state = IRTSP_PARSE_FRAME;
IRTSPParse->current_offset += frame_start - data;
goto start;
} else {
IRTSPParse->current_offset += data_size;
}
break;
case IRTSP_PARSE_FRAME:
if (data_size > 0 && data[0] != frame_header_magic) {
IRTSPParse->state = IRTSP_SEARCH_FRAME;
goto start;
}
if (data_size >= frame_header_size) {
IRTSPParse->current_offset += frame_header_size;
current_channel_id = data[1];
IRTSPParse->frame_size = GST_READ_UINT16_BE (&data[2]);
if (current_channel_id != IRTSPParse->target_channel_id) {
IRTSPParse->state = IRTSP_SKIP_FRAME;
} else {
IRTSPParse->state = IRTSP_FLUSH_FRAME;
}
goto start;
}
break;
case IRTSP_SKIP_FRAME:
if (data_size >= IRTSPParse->frame_size) {
IRTSPParse->current_offset += IRTSPParse->frame_size;
IRTSPParse->state = IRTSP_PARSE_FRAME;
goto start;
}
break;
case IRTSP_FLUSH_FRAME:
if (data_size >= IRTSPParse->frame_size) {
gst_irtsp_set_caps_once (parse);
gst_buffer_unmap (buf, &map);
frame->out_buffer = gst_buffer_copy (frame->buffer);
gst_buffer_resize (frame->out_buffer, IRTSPParse->current_offset,
IRTSPParse->frame_size);
if (G_UNLIKELY (IRTSPParse->discont)) {
GST_BUFFER_FLAG_SET (frame->out_buffer, GST_BUFFER_FLAG_DISCONT);
IRTSPParse->discont = FALSE;
}
flushed_size = IRTSPParse->current_offset + IRTSPParse->frame_size;
IRTSPParse->current_offset = 0;
IRTSPParse->state = IRTSP_PARSE_FRAME;
return gst_base_parse_finish_frame (parse, frame, flushed_size);
}
break;
default:
g_assert_not_reached ();
break;
}
gst_buffer_unmap (buf, &map);
return GST_FLOW_OK;
}
static void
gst_irtsp_parse_set_property (GObject * object,
guint prop_id, const GValue * value, GParamSpec * pspec)
{
GstIRTSPParse *IRTSPParse = GST_IRTSP_PARSE (object);
switch (prop_id) {
case PROP_CHANNEL_ID:
IRTSPParse->target_channel_id = g_value_get_int (value);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gst_irtsp_parse_get_property (GObject * object,
guint prop_id, GValue * value, GParamSpec * pspec)
{
GstIRTSPParse *IRTSPParse = GST_IRTSP_PARSE (object);
switch (prop_id) {
case PROP_CHANNEL_ID:
g_value_set_int (value, IRTSPParse->target_channel_id);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}