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 {
39 AVFormatContext *ic; /**< the containing (RTSP) demux context */
40 /** Each RDT stream-set (represented by one RTSPStream) can contain
41 * multiple streams (of the same content, but with possibly different
42 * codecs/bitrates). Each such stream is represented by one AVStream
43 * in the AVFormatContext, and this variable points to the offset in
44 * that array such that the first is the first stream of this set. */
46 int n_streams; /**< streams with identifical content in this set */
47 void *dynamic_protocol_context;
48 DynamicPayloadPacketHandlerProc parse_packet;
49 uint32_t prev_timestamp;
50 int prev_set_id, prev_stream_id;
54 ff_rdt_parse_open(AVFormatContext *ic, int first_stream_of_set_idx,
55 void *priv_data, RTPDynamicProtocolHandler *handler)
57 RDTDemuxContext *s = av_mallocz(sizeof(RDTDemuxContext));
62 s->streams = &ic->streams[first_stream_of_set_idx];
65 } while (first_stream_of_set_idx + s->n_streams < ic->nb_streams &&
66 s->streams[s->n_streams]->priv_data == s->streams[0]->priv_data);
68 s->prev_stream_id = -1;
69 s->prev_timestamp = -1;
70 s->parse_packet = handler->parse_packet;
71 s->dynamic_protocol_context = priv_data;
77 ff_rdt_parse_close(RDTDemuxContext *s)
82 struct PayloadContext {
83 AVFormatContext *rmctx;
85 unsigned int mlti_data_size;
86 char buffer[RTP_MAX_PACKET_LENGTH + FF_INPUT_BUFFER_PADDING_SIZE];
90 ff_rdt_calc_response_and_checksum(char response[41], char chksum[9],
91 const char *challenge)
93 int ch_len = strlen (challenge), i;
94 unsigned char zres[16],
95 buf[64] = { 0xa1, 0xe9, 0x14, 0x9d, 0x0e, 0x6b, 0x3b, 0x59 };
96 #define XOR_TABLE_SIZE 37
97 const unsigned char xor_table[XOR_TABLE_SIZE] = {
98 0x05, 0x18, 0x74, 0xd0, 0x0d, 0x09, 0x02, 0x53,
99 0xc0, 0x01, 0x05, 0x05, 0x67, 0x03, 0x19, 0x70,
100 0x08, 0x27, 0x66, 0x10, 0x10, 0x72, 0x08, 0x09,
101 0x63, 0x11, 0x03, 0x71, 0x08, 0x08, 0x70, 0x02,
102 0x10, 0x57, 0x05, 0x18, 0x54 };
104 /* some (length) checks */
105 if (ch_len == 40) /* what a hack... */
107 else if (ch_len > 56)
109 memcpy(buf + 8, challenge, ch_len);
111 /* xor challenge bytewise with xor_table */
112 for (i = 0; i < XOR_TABLE_SIZE; i++)
113 buf[8 + i] ^= xor_table[i];
115 av_md5_sum(zres, buf, 64);
116 ff_data_to_hex(response, zres, 16);
117 for (i=0;i<32;i++) response[i] = tolower(response[i]);
120 strcpy (response + 32, "01d0a8e3");
122 /* calculate checksum */
123 for (i = 0; i < 8; i++)
124 chksum[i] = response[i * 4];
129 rdt_load_mdpr (PayloadContext *rdt, AVStream *st, int rule_nr)
136 * Layout of the MLTI chunk:
138 * 2:<number of streams>
139 * Then for each stream ([number_of_streams] times):
141 * 2:<number of mdpr chunks>
142 * Then for each mdpr chunk ([number_of_mdpr_chunks] times):
145 * we skip MDPR chunks until we reach the one of the stream
146 * we're interested in, and forward that ([size]+[data]) to
147 * the RM demuxer to parse the stream-specific header data.
151 init_put_byte(&pb, rdt->mlti_data, rdt->mlti_data_size, 0,
152 NULL, NULL, NULL, NULL);
154 if (tag == MKTAG('M', 'L', 'T', 'I')) {
157 /* read index of MDPR chunk numbers */
159 if (rule_nr < 0 || rule_nr >= num)
161 url_fskip(&pb, rule_nr * 2);
162 chunk_nr = get_be16(&pb);
163 url_fskip(&pb, (num - 1 - rule_nr) * 2);
165 /* read MDPR chunks */
170 url_fskip(&pb, get_be32(&pb));
171 size = get_be32(&pb);
173 size = rdt->mlti_data_size;
174 url_fseek(&pb, 0, SEEK_SET);
176 if (ff_rm_read_mdpr_codecdata(rdt->rmctx, &pb, st, size) < 0)
183 * Actual data handling.
187 ff_rdt_parse_header(const uint8_t *buf, int len,
188 int *pset_id, int *pseq_no, int *pstream_id,
189 int *pis_keyframe, uint32_t *ptimestamp)
192 int consumed = 0, set_id, seq_no, stream_id, is_keyframe,
193 len_included, need_reliable;
196 /* skip status packets */
197 while (len >= 5 && buf[1] == 0xFF /* status packet */) {
200 if (!(buf[0] & 0x80))
201 return -1; /* not followed by a data packet */
203 pkt_len = AV_RB16(buf+3);
211 * Layout of the header (in bits):
213 * Flag indicating whether this header includes a length field;
214 * this can be used to concatenate multiple RDT packets in a
215 * single UDP/TCP data frame and is used to precede RDT data
216 * by stream status packets
218 * Flag indicating whether this header includes a "reliable
219 * sequence number"; these are apparently sequence numbers of
220 * data packets alone. For data packets, this flag is always
221 * set, according to the Real documentation [1]
223 * ID of a set of streams of identical content, possibly with
224 * different codecs or bitrates
226 * Flag set for certain streams deemed less tolerable for packet
229 * Packet sequence number; if >=0xFF00, this is a non-data packet
230 * containing stream status info, the second byte indicates the
231 * type of status packet (see wireshark docs / source code [2])
232 * if (len_included) {
235 * packet_len = remainder of UDP/TCP frame
238 * Back-to-Back flag; used for timing, set for one in every 10
239 * packets, according to the Real documentation [1]
241 * Slow-data flag; currently unused, according to Real docs [1]
243 * ID of the stream within this particular set of streams
245 * Non-keyframe flag (unset if packet belongs to a keyframe)
246 * 32: timestamp (PTS)
247 * if (set_id == 0x1F) {
248 * 16: set_id (extended set-of-streams ID; see set_id)
250 * if (need_reliable) {
251 * 16: reliable_seq_no
252 * Reliable sequence number (see need_reliable)
254 * if (stream_id == 0x3F) {
255 * 16: stream_id (extended stream ID; see stream_id)
257 * [1] https://protocol.helixcommunity.org/files/2005/devdocs/RDT_Feature_Level_20.txt
258 * [2] http://www.wireshark.org/docs/dfref/r/rdt.html and
259 * http://anonsvn.wireshark.org/viewvc/trunk/epan/dissectors/packet-rdt.c
261 init_get_bits(&gb, buf, len << 3);
262 len_included = get_bits1(&gb);
263 need_reliable = get_bits1(&gb);
264 set_id = get_bits(&gb, 5);
266 seq_no = get_bits(&gb, 16);
270 stream_id = get_bits(&gb, 5);
271 is_keyframe = !get_bits1(&gb);
272 timestamp = get_bits_long(&gb, 32);
274 set_id = get_bits(&gb, 16);
277 if (stream_id == 0x1f)
278 stream_id = get_bits(&gb, 16);
280 if (pset_id) *pset_id = set_id;
281 if (pseq_no) *pseq_no = seq_no;
282 if (pstream_id) *pstream_id = stream_id;
283 if (pis_keyframe) *pis_keyframe = is_keyframe;
284 if (ptimestamp) *ptimestamp = timestamp;
286 return consumed + (get_bits_count(&gb) >> 3);
289 /**< return 0 on packet, no more left, 1 on packet, 1 on partial packet... */
291 rdt_parse_packet (PayloadContext *rdt, AVStream *st,
292 AVPacket *pkt, uint32_t *timestamp,
293 const uint8_t *buf, int len, int flags)
297 RMContext *rm = rdt->rmctx->priv_data;
299 if (rm->audio_pkt_cnt == 0) {
302 init_put_byte(&pb, buf, len, 0, NULL, NULL, NULL, NULL);
303 flags = (flags & PKT_FLAG_KEY) ? 2 : 0;
304 res = ff_rm_parse_packet (rdt->rmctx, &pb, st, len, pkt,
305 &seq, &flags, timestamp);
306 pos = url_ftell(&pb);
309 if (rm->audio_pkt_cnt > 0 &&
310 st->codec->codec_id == CODEC_ID_AAC) {
311 memcpy (rdt->buffer, buf + pos, len - pos);
312 rdt->rmctx->pb = av_alloc_put_byte (rdt->buffer, len - pos, 0,
313 NULL, NULL, NULL, NULL);
316 ff_rm_retrieve_cache (rdt->rmctx, rdt->rmctx->pb, st, pkt);
317 if (rm->audio_pkt_cnt == 0 &&
318 st->codec->codec_id == CODEC_ID_AAC)
319 av_freep(&rdt->rmctx->pb);
321 pkt->stream_index = st->index;
322 pkt->pts = *timestamp;
324 return rm->audio_pkt_cnt > 0;
328 ff_rdt_parse_packet(RDTDemuxContext *s, AVPacket *pkt,
329 const uint8_t *buf, int len)
331 int seq_no, flags = 0, stream_id, set_id, is_keyframe;
335 if (!s->parse_packet)
338 if (!buf && s->prev_stream_id != -1) {
339 /* return the next packets, if any */
340 timestamp= 0; ///< Should not be used if buf is NULL, but should be set to the timestamp of the packet returned....
341 rv= s->parse_packet(s->dynamic_protocol_context,
342 s->streams[s->prev_stream_id],
343 pkt, ×tamp, NULL, 0, flags);
349 rv = ff_rdt_parse_header(buf, len, &set_id, &seq_no, &stream_id, &is_keyframe, ×tamp);
353 (set_id != s->prev_set_id || timestamp != s->prev_timestamp ||
354 stream_id != s->prev_stream_id)) {
355 flags |= PKT_FLAG_KEY;
356 s->prev_set_id = set_id;
357 s->prev_timestamp = timestamp;
359 s->prev_stream_id = stream_id;
363 if (s->prev_stream_id >= s->n_streams) {
364 s->prev_stream_id = -1;
368 rv = s->parse_packet(s->dynamic_protocol_context,
369 s->streams[s->prev_stream_id],
370 pkt, ×tamp, buf, len, flags);
376 ff_rdt_subscribe_rule (char *cmd, int size,
377 int stream_nr, int rule_nr)
379 av_strlcatf(cmd, size, "stream=%d;rule=%d,stream=%d;rule=%d",
380 stream_nr, rule_nr * 2, stream_nr, rule_nr * 2 + 1);
384 ff_rdt_subscribe_rule2 (RDTDemuxContext *s, char *cmd, int size,
385 int stream_nr, int rule_nr)
387 PayloadContext *rdt = s->dynamic_protocol_context;
389 rdt_load_mdpr(rdt, s->streams[0], rule_nr * 2);
392 static unsigned char *
393 rdt_parse_b64buf (unsigned int *target_len, const char *p)
395 unsigned char *target;
399 len -= 2; /* skip embracing " at start/end */
401 *target_len = len * 3 / 4;
402 target = av_mallocz(*target_len + FF_INPUT_BUFFER_PADDING_SIZE);
403 av_base64_decode(target, p, *target_len);
408 rdt_parse_sdp_line (AVFormatContext *s, int st_index,
409 PayloadContext *rdt, const char *line)
411 AVStream *stream = s->streams[st_index];
412 const char *p = line;
414 if (av_strstart(p, "OpaqueData:buffer;", &p)) {
415 rdt->mlti_data = rdt_parse_b64buf(&rdt->mlti_data_size, p);
416 } else if (av_strstart(p, "StartTime:integer;", &p))
417 stream->first_dts = atoi(p);
422 static PayloadContext *
423 rdt_new_extradata (void)
425 PayloadContext *rdt = av_mallocz(sizeof(PayloadContext));
427 av_open_input_stream(&rdt->rmctx, NULL, "", &rdt_demuxer, NULL);
433 rdt_free_extradata (PayloadContext *rdt)
436 av_close_input_stream(rdt->rmctx);
437 av_freep(&rdt->mlti_data);
441 #define RDT_HANDLER(n, s, t) \
442 static RTPDynamicProtocolHandler ff_rdt_ ## n ## _handler = { \
446 rdt_parse_sdp_line, \
448 rdt_free_extradata, \
452 RDT_HANDLER(live_video, "x-pn-multirate-realvideo-live", CODEC_TYPE_VIDEO);
453 RDT_HANDLER(live_audio, "x-pn-multirate-realaudio-live", CODEC_TYPE_AUDIO);
454 RDT_HANDLER(video, "x-pn-realvideo", CODEC_TYPE_VIDEO);
455 RDT_HANDLER(audio, "x-pn-realaudio", CODEC_TYPE_AUDIO);
457 void av_register_rdt_dynamic_payload_handlers(void)
459 ff_register_dynamic_payload_handler(&ff_rdt_video_handler);
460 ff_register_dynamic_payload_handler(&ff_rdt_audio_handler);
461 ff_register_dynamic_payload_handler(&ff_rdt_live_video_handler);
462 ff_register_dynamic_payload_handler(&ff_rdt_live_audio_handler);