2 * Realmedia RTSP protocol (RDT) support.
3 * Copyright (c) 2007 Ronald S. Bultje
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24 * @brief Realmedia RTSP protocol (RDT) support
25 * @author Ronald S. Bultje <rbultje@ronald.bitfreak.net>
29 #include "libavutil/avstring.h"
30 #include "rtp_internal.h"
32 #include "libavutil/base64.h"
33 #include "libavutil/md5.h"
36 #include <libavcodec/bitstream.h>
38 struct RDTDemuxContext {
41 void *dynamic_protocol_context;
42 DynamicPayloadPacketHandlerProc parse_packet;
43 uint32_t prev_timestamp;
48 ff_rdt_parse_open(AVFormatContext *ic, AVStream *st,
49 void *priv_data, RTPDynamicProtocolHandler *handler)
51 RDTDemuxContext *s = av_mallocz(sizeof(RDTDemuxContext));
58 s->prev_timestamp = -1;
59 s->parse_packet = handler->parse_packet;
60 s->dynamic_protocol_context = priv_data;
66 ff_rdt_parse_close(RDTDemuxContext *s)
71 struct PayloadContext {
72 AVFormatContext *rmctx;
74 unsigned int mlti_data_size;
75 char buffer[RTP_MAX_PACKET_LENGTH + FF_INPUT_BUFFER_PADDING_SIZE];
79 ff_rdt_calc_response_and_checksum(char response[41], char chksum[9],
80 const char *challenge)
82 int ch_len = strlen (challenge), i;
83 unsigned char zres[16],
84 buf[64] = { 0xa1, 0xe9, 0x14, 0x9d, 0x0e, 0x6b, 0x3b, 0x59 };
85 #define XOR_TABLE_SIZE 37
86 const unsigned char xor_table[XOR_TABLE_SIZE] = {
87 0x05, 0x18, 0x74, 0xd0, 0x0d, 0x09, 0x02, 0x53,
88 0xc0, 0x01, 0x05, 0x05, 0x67, 0x03, 0x19, 0x70,
89 0x08, 0x27, 0x66, 0x10, 0x10, 0x72, 0x08, 0x09,
90 0x63, 0x11, 0x03, 0x71, 0x08, 0x08, 0x70, 0x02,
91 0x10, 0x57, 0x05, 0x18, 0x54 };
93 /* some (length) checks */
94 if (ch_len == 40) /* what a hack... */
98 memcpy(buf + 8, challenge, ch_len);
100 /* xor challenge bytewise with xor_table */
101 for (i = 0; i < XOR_TABLE_SIZE; i++)
102 buf[8 + i] ^= xor_table[i];
104 av_md5_sum(zres, buf, 64);
105 ff_data_to_hex(response, zres, 16);
106 for (i=0;i<32;i++) response[i] = tolower(response[i]);
109 strcpy (response + 32, "01d0a8e3");
111 /* calculate checksum */
112 for (i = 0; i < 8; i++)
113 chksum[i] = response[i * 4];
118 rdt_load_mdpr (PayloadContext *rdt, AVStream *st, int rule_nr)
125 * Layout of the MLTI chunk:
127 * 2:<number of streams>
128 * Then for each stream ([number_of_streams] times):
130 * 2:<number of mdpr chunks>
131 * Then for each mdpr chunk ([number_of_mdpr_chunks] times):
134 * we skip MDPR chunks until we reach the one of the stream
135 * we're interested in, and forward that ([size]+[data]) to
136 * the RM demuxer to parse the stream-specific header data.
140 init_put_byte(&pb, rdt->mlti_data, rdt->mlti_data_size, 0,
141 NULL, NULL, NULL, NULL);
143 if (tag == MKTAG('M', 'L', 'T', 'I')) {
146 /* read index of MDPR chunk numbers */
148 if (rule_nr < 0 || rule_nr >= num)
150 url_fskip(&pb, rule_nr * 2);
151 chunk_nr = get_be16(&pb);
152 url_fskip(&pb, (num - 1 - rule_nr) * 2);
154 /* read MDPR chunks */
159 url_fskip(&pb, get_be32(&pb));
160 size = get_be32(&pb);
162 size = rdt->mlti_data_size;
163 url_fseek(&pb, 0, SEEK_SET);
165 if (ff_rm_read_mdpr_codecdata(rdt->rmctx, &pb, st, size) < 0)
172 * Actual data handling.
176 ff_rdt_parse_header(const uint8_t *buf, int len,
177 int *pset_id, int *pseq_no, int *pstream_id,
178 int *pis_keyframe, uint32_t *ptimestamp)
181 int consumed = 0, set_id, seq_no, stream_id, is_keyframe,
182 len_included, need_reliable;
185 /* skip status packets */
186 while (len >= 5 && buf[1] == 0xFF /* status packet */) {
189 if (!(buf[0] & 0x80))
190 return -1; /* not followed by a data packet */
192 pkt_len = AV_RB16(buf+3);
200 * Layout of the header (in bits):
202 * Flag indicating whether this header includes a length field;
203 * this can be used to concatenate multiple RDT packets in a
204 * single UDP/TCP data frame and is used to precede RDT data
205 * by stream status packets
207 * Flag indicating whether this header includes a "reliable
208 * sequence number"; these are apparently sequence numbers of
209 * data packets alone. For data packets, this flag is always
210 * set, according to the Real documentation [1]
212 * ID of a set of streams of identical content, possibly with
213 * different codecs or bitrates
215 * Flag set for certain streams deemed less tolerable for packet
218 * Packet sequence number; if >=0xFF00, this is a non-data packet
219 * containing stream status info, the second byte indicates the
220 * type of status packet (see wireshark docs / source code [2])
221 * if (len_included) {
224 * packet_len = remainder of UDP/TCP frame
227 * Back-to-Back flag; used for timing, set for one in every 10
228 * packets, according to the Real documentation [1]
230 * Slow-data flag; currently unused, according to Real docs [1]
232 * ID of the stream within this particular set of streams
234 * Non-keyframe flag (unset if packet belongs to a keyframe)
235 * 32: timestamp (PTS)
236 * if (set_id == 0x1F) {
237 * 16: set_id (extended set-of-streams ID; see set_id)
239 * if (need_reliable) {
240 * 16: reliable_seq_no
241 * Reliable sequence number (see need_reliable)
243 * if (stream_id == 0x3F) {
244 * 16: stream_id (extended stream ID; see stream_id)
246 * [1] https://protocol.helixcommunity.org/files/2005/devdocs/RDT_Feature_Level_20.txt
247 * [2] http://www.wireshark.org/docs/dfref/r/rdt.html and
248 * http://anonsvn.wireshark.org/viewvc/trunk/epan/dissectors/packet-rdt.c
250 init_get_bits(&gb, buf, len << 3);
251 len_included = get_bits1(&gb);
252 need_reliable = get_bits1(&gb);
253 set_id = get_bits(&gb, 5);
255 seq_no = get_bits(&gb, 16);
259 stream_id = get_bits(&gb, 5);
260 is_keyframe = !get_bits1(&gb);
261 timestamp = get_bits_long(&gb, 32);
263 set_id = get_bits(&gb, 16);
266 if (stream_id == 0x1f)
267 stream_id = get_bits(&gb, 16);
269 if (pset_id) *pset_id = set_id;
270 if (pseq_no) *pseq_no = seq_no;
271 if (pstream_id) *pstream_id = stream_id;
272 if (pis_keyframe) *pis_keyframe = is_keyframe;
273 if (ptimestamp) *ptimestamp = timestamp;
275 return consumed + (get_bits_count(&gb) >> 3);
278 /**< return 0 on packet, no more left, 1 on packet, 1 on partial packet... */
280 rdt_parse_packet (PayloadContext *rdt, AVStream *st,
281 AVPacket *pkt, uint32_t *timestamp,
282 const uint8_t *buf, int len, int flags)
286 RMContext *rm = rdt->rmctx->priv_data;
288 if (rm->audio_pkt_cnt == 0) {
291 init_put_byte(&pb, buf, len, 0, NULL, NULL, NULL, NULL);
292 flags = (flags & PKT_FLAG_KEY) ? 2 : 0;
293 res = ff_rm_parse_packet (rdt->rmctx, &pb, st, len, pkt,
294 &seq, &flags, timestamp);
295 pos = url_ftell(&pb);
298 if (rm->audio_pkt_cnt > 0 &&
299 st->codec->codec_id == CODEC_ID_AAC) {
300 memcpy (rdt->buffer, buf + pos, len - pos);
301 rdt->rmctx->pb = av_alloc_put_byte (rdt->buffer, len - pos, 0,
302 NULL, NULL, NULL, NULL);
305 ff_rm_retrieve_cache (rdt->rmctx, rdt->rmctx->pb, st, pkt);
306 if (rm->audio_pkt_cnt == 0 &&
307 st->codec->codec_id == CODEC_ID_AAC)
308 av_freep(&rdt->rmctx->pb);
310 pkt->stream_index = st->index;
311 pkt->pts = *timestamp;
313 return rm->audio_pkt_cnt > 0;
317 ff_rdt_parse_packet(RDTDemuxContext *s, AVPacket *pkt,
318 const uint8_t *buf, int len)
320 int seq_no, flags = 0, stream_id, set_id, is_keyframe;
324 if (!s->parse_packet)
328 /* return the next packets, if any */
329 timestamp= 0; ///< Should not be used if buf is NULL, but should be set to the timestamp of the packet returned....
330 rv= s->parse_packet(s->dynamic_protocol_context,
331 s->st, pkt, ×tamp, NULL, 0, flags);
337 rv = ff_rdt_parse_header(buf, len, &set_id, &seq_no, &stream_id, &is_keyframe, ×tamp);
340 if (is_keyframe && (set_id != s->prev_set_id || timestamp != s->prev_timestamp)) {
341 flags |= PKT_FLAG_KEY;
342 s->prev_set_id = set_id;
343 s->prev_timestamp = timestamp;
348 rv = s->parse_packet(s->dynamic_protocol_context,
349 s->st, pkt, ×tamp, buf, len, flags);
355 ff_rdt_subscribe_rule (char *cmd, int size,
356 int stream_nr, int rule_nr)
358 av_strlcatf(cmd, size, "stream=%d;rule=%d,stream=%d;rule=%d",
359 stream_nr, rule_nr * 2, stream_nr, rule_nr * 2 + 1);
363 ff_rdt_subscribe_rule2 (RDTDemuxContext *s, char *cmd, int size,
364 int stream_nr, int rule_nr)
366 PayloadContext *rdt = s->dynamic_protocol_context;
368 rdt_load_mdpr(rdt, s->st, rule_nr * 2);
371 static unsigned char *
372 rdt_parse_b64buf (unsigned int *target_len, const char *p)
374 unsigned char *target;
378 len -= 2; /* skip embracing " at start/end */
380 *target_len = len * 3 / 4;
381 target = av_mallocz(*target_len + FF_INPUT_BUFFER_PADDING_SIZE);
382 av_base64_decode(target, p, *target_len);
387 rdt_parse_sdp_line (AVStream *stream, PayloadContext *rdt, const char *line)
389 const char *p = line;
391 if (av_strstart(p, "OpaqueData:buffer;", &p)) {
392 rdt->mlti_data = rdt_parse_b64buf(&rdt->mlti_data_size, p);
393 } else if (av_strstart(p, "StartTime:integer;", &p))
394 stream->first_dts = atoi(p);
399 static PayloadContext *
400 rdt_new_extradata (void)
402 PayloadContext *rdt = av_mallocz(sizeof(PayloadContext));
404 av_open_input_stream(&rdt->rmctx, NULL, "", &rdt_demuxer, NULL);
410 rdt_free_extradata (PayloadContext *rdt)
413 av_close_input_stream(rdt->rmctx);
414 av_freep(&rdt->mlti_data);
418 #define RDT_HANDLER(n, s, t) \
419 static RTPDynamicProtocolHandler ff_rdt_ ## n ## _handler = { \
423 rdt_parse_sdp_line, \
425 rdt_free_extradata, \
429 RDT_HANDLER(live_video, "x-pn-multirate-realvideo-live", CODEC_TYPE_VIDEO);
430 RDT_HANDLER(live_audio, "x-pn-multirate-realaudio-live", CODEC_TYPE_AUDIO);
431 RDT_HANDLER(video, "x-pn-realvideo", CODEC_TYPE_VIDEO);
432 RDT_HANDLER(audio, "x-pn-realaudio", CODEC_TYPE_AUDIO);
434 void av_register_rdt_dynamic_payload_handlers(void)
436 ff_register_dynamic_payload_handler(&ff_rdt_video_handler);
437 ff_register_dynamic_payload_handler(&ff_rdt_audio_handler);
438 ff_register_dynamic_payload_handler(&ff_rdt_live_video_handler);
439 ff_register_dynamic_payload_handler(&ff_rdt_live_audio_handler);