1 /* GStreamer Interleaved RTSP parser
2 * Copyright (C) 2011 Mark Nauwelaerts <mark.nauwelaerts@collabora.co.uk>
3 * Copyright (C) 2011 Nokia Corporation. All rights reserved.
4 * Contact: Stefan Kost <stefan.kost@nokia.com>
5 *
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Library General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
10 *
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Library General Public License for more details.
15 *
16 * You should have received a copy of the GNU Library General Public
17 * License along with this library; if not, write to the
18 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
19 * Boston, MA 02110-1301, USA.
20 */
21 /**
22 * SECTION:element-irtspparse
23 * @title: irtspparse
24 * @short_description: Interleaved RTSP parser
25 * @see_also: #GstPcapParse
26 *
27 * This is an interleaved RTSP parser that allows extracting specific
28 * so-called "channels" from received interleaved (TCP) RTSP data
29 * (typically extracted from some network capture).
30 *
31 * ## Example launch line
32 * |[
33 * gst-launch-1.0 filesrc location=h264crasher.pcap ! pcapparse ! irtspparse
34 * ! rtph264depay ! ffdec_h264 ! fakesink
35 * ]| Read from a pcap dump file using filesrc, extract the raw TCP packets,
36 * depayload and decode them.
37 *
38 */
39
40 #ifdef HAVE_CONFIG_H
41 #include "config.h"
42 #endif
43
44 #include <string.h>
45
46 #include "gstirtspparse.h"
47 #include <gst/base/gstbytereader.h>
48
49 GST_DEBUG_CATEGORY_STATIC (irtsp_parse_debug);
50 #define GST_CAT_DEFAULT irtsp_parse_debug
51
52 enum
53 {
54 PROP_0,
55 PROP_CHANNEL_ID
56 };
57
58
59 static GstStaticPadTemplate src_template = GST_STATIC_PAD_TEMPLATE ("src",
60 GST_PAD_SRC,
61 GST_PAD_ALWAYS,
62 GST_STATIC_CAPS ("application/x-rtp ; application/x-rtcp"));
63
64 static GstStaticPadTemplate sink_template = GST_STATIC_PAD_TEMPLATE ("sink",
65 GST_PAD_SINK,
66 GST_PAD_ALWAYS,
67 GST_STATIC_CAPS_ANY);
68
69 static void gst_irtsp_parse_finalize (GObject * object);
70
71 static gboolean gst_irtsp_parse_start (GstBaseParse * parse);
72 static gboolean gst_irtsp_parse_stop (GstBaseParse * parse);
73 static GstFlowReturn gst_irtsp_parse_handle_frame (GstBaseParse * parse,
74 GstBaseParseFrame * frame, gint * skipsize);
75
76 static void gst_irtsp_parse_set_property (GObject * object,
77 guint prop_id, const GValue * value, GParamSpec * pspec);
78 static void gst_irtsp_parse_get_property (GObject * object,
79 guint prop_id, GValue * value, GParamSpec * pspec);
80
81 #define parent_class gst_irtsp_parse_parent_class
82 G_DEFINE_TYPE (GstIRTSPParse, gst_irtsp_parse, GST_TYPE_BASE_PARSE);
83 GST_ELEMENT_REGISTER_DEFINE (irtspparse, "irtspparse", GST_RANK_NONE,
84 GST_TYPE_IRTSP_PARSE);
85
86 static void
gst_irtsp_parse_class_init(GstIRTSPParseClass * klass)87 gst_irtsp_parse_class_init (GstIRTSPParseClass * klass)
88 {
89 GstBaseParseClass *parse_class = GST_BASE_PARSE_CLASS (klass);
90 GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
91 GObjectClass *object_class = G_OBJECT_CLASS (klass);
92
93 GST_DEBUG_CATEGORY_INIT (irtsp_parse_debug, "irtspparse", 0,
94 "Interleaved RTSP stream parser");
95
96 object_class->finalize = gst_irtsp_parse_finalize;
97
98 object_class->set_property = gst_irtsp_parse_set_property;
99 object_class->get_property = gst_irtsp_parse_get_property;
100
101 g_object_class_install_property (object_class, PROP_CHANNEL_ID,
102 g_param_spec_int ("channel-id", "channel-id",
103 "Channel Identifier", 0, 255,
104 0, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
105
106 parse_class->start = GST_DEBUG_FUNCPTR (gst_irtsp_parse_start);
107 parse_class->stop = GST_DEBUG_FUNCPTR (gst_irtsp_parse_stop);
108 parse_class->handle_frame = GST_DEBUG_FUNCPTR (gst_irtsp_parse_handle_frame);
109
110 gst_element_class_add_static_pad_template (element_class, &sink_template);
111 gst_element_class_add_static_pad_template (element_class, &src_template);
112
113 gst_element_class_set_static_metadata (element_class, "IRTSPParse",
114 "Raw/Parser",
115 "Parses a raw interleaved RTSP stream",
116 "Mark Nauwelaerts <mark.nauwelaerts@collabora.co.uk>");
117 }
118
119 static void
gst_irtsp_parse_reset(GstIRTSPParse * IRTSPParse)120 gst_irtsp_parse_reset (GstIRTSPParse * IRTSPParse)
121 {
122 IRTSPParse->state = IRTSP_SEARCH_FRAME;
123 IRTSPParse->current_offset = 0;
124 IRTSPParse->discont = FALSE;
125 }
126
127 static void
gst_irtsp_parse_init(GstIRTSPParse * IRTSPParse)128 gst_irtsp_parse_init (GstIRTSPParse * IRTSPParse)
129 {
130 gst_base_parse_set_min_frame_size (GST_BASE_PARSE (IRTSPParse), 1);
131 gst_irtsp_parse_reset (IRTSPParse);
132 }
133
134 static void
gst_irtsp_parse_finalize(GObject * object)135 gst_irtsp_parse_finalize (GObject * object)
136 {
137 G_OBJECT_CLASS (parent_class)->finalize (object);
138 }
139
140 static gboolean
gst_irtsp_parse_start(GstBaseParse * parse)141 gst_irtsp_parse_start (GstBaseParse * parse)
142 {
143 GstIRTSPParse *IRTSPParse = GST_IRTSP_PARSE (parse);
144
145 GST_DEBUG_OBJECT (parse, "starting");
146
147 gst_irtsp_parse_reset (IRTSPParse);
148
149 return TRUE;
150 }
151
152 static gboolean
gst_irtsp_parse_stop(GstBaseParse * parse)153 gst_irtsp_parse_stop (GstBaseParse * parse)
154 {
155 GST_DEBUG_OBJECT (parse, "stopping");
156
157 return TRUE;
158 }
159
160 static void
gst_irtsp_set_caps_once(GstBaseParse * parse)161 gst_irtsp_set_caps_once (GstBaseParse * parse)
162 {
163 if (!gst_pad_has_current_caps (GST_BASE_PARSE_SRC_PAD (parse))) {
164 GstCaps *caps = gst_caps_new_empty_simple ("application/x-rtp");
165 gst_pad_set_caps (GST_BASE_PARSE_SRC_PAD (parse), caps);
166 gst_caps_unref (caps);
167 }
168 }
169
170 static GstFlowReturn
gst_irtsp_parse_handle_frame(GstBaseParse * parse,GstBaseParseFrame * frame,gint * skipsize)171 gst_irtsp_parse_handle_frame (GstBaseParse * parse,
172 GstBaseParseFrame * frame, gint * skipsize)
173 {
174 static const guint frame_header_size = sizeof (guint8) * 4;
175 static const guint8 frame_header_magic = 0x24;
176 GstIRTSPParse *IRTSPParse = GST_IRTSP_PARSE (parse);
177 GstBuffer *buf = frame->buffer;
178 GstMapInfo map;
179 const guint8 *frame_start;
180 guint8 current_channel_id;
181 const guint8 *data;
182 guint data_size;
183 guint flushed_size;
184
185 if (G_UNLIKELY (GST_BUFFER_FLAG_IS_SET (frame->buffer,
186 GST_BUFFER_FLAG_DISCONT))) {
187 IRTSPParse->discont = TRUE;
188 }
189
190 gst_buffer_map (buf, &map, GST_MAP_READ);
191
192 start:
193 g_assert (map.size >= IRTSPParse->current_offset);
194 data = &map.data[IRTSPParse->current_offset];
195 data_size = map.size - IRTSPParse->current_offset;
196
197 switch (IRTSPParse->state) {
198 case IRTSP_SEARCH_FRAME:
199 /* Use the first occurrence of 0x24 as a start of interleaved frames.
200 * This 'trick' allows us to parse a dump that doesn't contain RTSP
201 * handshake. It's up to user to provide the data where the first 0x24
202 * is an RTSP frame */
203 frame_start = memchr (data, frame_header_magic, data_size);
204 if (frame_start) {
205 IRTSPParse->state = IRTSP_PARSE_FRAME;
206 IRTSPParse->current_offset += frame_start - data;
207 goto start;
208 } else {
209 IRTSPParse->current_offset += data_size;
210 }
211 break;
212 case IRTSP_PARSE_FRAME:
213 if (data_size > 0 && data[0] != frame_header_magic) {
214 IRTSPParse->state = IRTSP_SEARCH_FRAME;
215 goto start;
216 }
217
218 if (data_size >= frame_header_size) {
219 IRTSPParse->current_offset += frame_header_size;
220 current_channel_id = data[1];
221 IRTSPParse->frame_size = GST_READ_UINT16_BE (&data[2]);
222 if (current_channel_id != IRTSPParse->target_channel_id) {
223 IRTSPParse->state = IRTSP_SKIP_FRAME;
224 } else {
225 IRTSPParse->state = IRTSP_FLUSH_FRAME;
226 }
227 goto start;
228 }
229 break;
230 case IRTSP_SKIP_FRAME:
231 if (data_size >= IRTSPParse->frame_size) {
232 IRTSPParse->current_offset += IRTSPParse->frame_size;
233 IRTSPParse->state = IRTSP_PARSE_FRAME;
234 goto start;
235 }
236 break;
237 case IRTSP_FLUSH_FRAME:
238 if (data_size >= IRTSPParse->frame_size) {
239 gst_irtsp_set_caps_once (parse);
240 gst_buffer_unmap (buf, &map);
241
242 frame->out_buffer = gst_buffer_copy (frame->buffer);
243 gst_buffer_resize (frame->out_buffer, IRTSPParse->current_offset,
244 IRTSPParse->frame_size);
245
246 if (G_UNLIKELY (IRTSPParse->discont)) {
247 GST_BUFFER_FLAG_SET (frame->out_buffer, GST_BUFFER_FLAG_DISCONT);
248 IRTSPParse->discont = FALSE;
249 }
250
251 flushed_size = IRTSPParse->current_offset + IRTSPParse->frame_size;
252 IRTSPParse->current_offset = 0;
253 IRTSPParse->state = IRTSP_PARSE_FRAME;
254
255 return gst_base_parse_finish_frame (parse, frame, flushed_size);
256 }
257
258 break;
259 default:
260 g_assert_not_reached ();
261 break;
262 }
263
264 gst_buffer_unmap (buf, &map);
265 return GST_FLOW_OK;
266 }
267
268 static void
gst_irtsp_parse_set_property(GObject * object,guint prop_id,const GValue * value,GParamSpec * pspec)269 gst_irtsp_parse_set_property (GObject * object,
270 guint prop_id, const GValue * value, GParamSpec * pspec)
271 {
272 GstIRTSPParse *IRTSPParse = GST_IRTSP_PARSE (object);
273
274 switch (prop_id) {
275 case PROP_CHANNEL_ID:
276 IRTSPParse->target_channel_id = g_value_get_int (value);
277 break;
278 default:
279 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
280 break;
281 }
282 }
283
284 static void
gst_irtsp_parse_get_property(GObject * object,guint prop_id,GValue * value,GParamSpec * pspec)285 gst_irtsp_parse_get_property (GObject * object,
286 guint prop_id, GValue * value, GParamSpec * pspec)
287 {
288 GstIRTSPParse *IRTSPParse = GST_IRTSP_PARSE (object);
289
290 switch (prop_id) {
291 case PROP_CHANNEL_ID:
292 g_value_set_int (value, IRTSPParse->target_channel_id);
293 break;
294 default:
295 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
296 break;
297 }
298 }
299