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;
84 RMStream *rmst[MAX_STREAMS];
86 unsigned int mlti_data_size;
87 char buffer[RTP_MAX_PACKET_LENGTH + FF_INPUT_BUFFER_PADDING_SIZE];
88 int audio_pkt_cnt; /**< remaining audio packets in rmdec */
92 ff_rdt_calc_response_and_checksum(char response[41], char chksum[9],
93 const char *challenge)
95 int ch_len = strlen (challenge), i;
96 unsigned char zres[16],
97 buf[64] = { 0xa1, 0xe9, 0x14, 0x9d, 0x0e, 0x6b, 0x3b, 0x59 };
98 #define XOR_TABLE_SIZE 37
99 const unsigned char xor_table[XOR_TABLE_SIZE] = {
100 0x05, 0x18, 0x74, 0xd0, 0x0d, 0x09, 0x02, 0x53,
101 0xc0, 0x01, 0x05, 0x05, 0x67, 0x03, 0x19, 0x70,
102 0x08, 0x27, 0x66, 0x10, 0x10, 0x72, 0x08, 0x09,
103 0x63, 0x11, 0x03, 0x71, 0x08, 0x08, 0x70, 0x02,
104 0x10, 0x57, 0x05, 0x18, 0x54 };
106 /* some (length) checks */
107 if (ch_len == 40) /* what a hack... */
109 else if (ch_len > 56)
111 memcpy(buf + 8, challenge, ch_len);
113 /* xor challenge bytewise with xor_table */
114 for (i = 0; i < XOR_TABLE_SIZE; i++)
115 buf[8 + i] ^= xor_table[i];
117 av_md5_sum(zres, buf, 64);
118 ff_data_to_hex(response, zres, 16);
119 for (i=0;i<32;i++) response[i] = tolower(response[i]);
122 strcpy (response + 32, "01d0a8e3");
124 /* calculate checksum */
125 for (i = 0; i < 8; i++)
126 chksum[i] = response[i * 4];
131 rdt_load_mdpr (PayloadContext *rdt, AVStream *st, int rule_nr)
138 * Layout of the MLTI chunk:
140 * 2:<number of streams>
141 * Then for each stream ([number_of_streams] times):
143 * 2:<number of mdpr chunks>
144 * Then for each mdpr chunk ([number_of_mdpr_chunks] times):
147 * we skip MDPR chunks until we reach the one of the stream
148 * we're interested in, and forward that ([size]+[data]) to
149 * the RM demuxer to parse the stream-specific header data.
153 init_put_byte(&pb, rdt->mlti_data, rdt->mlti_data_size, 0,
154 NULL, NULL, NULL, NULL);
156 if (tag == MKTAG('M', 'L', 'T', 'I')) {
159 /* read index of MDPR chunk numbers */
161 if (rule_nr < 0 || rule_nr >= num)
163 url_fskip(&pb, rule_nr * 2);
164 chunk_nr = get_be16(&pb);
165 url_fskip(&pb, (num - 1 - rule_nr) * 2);
167 /* read MDPR chunks */
172 url_fskip(&pb, get_be32(&pb));
173 size = get_be32(&pb);
175 size = rdt->mlti_data_size;
176 url_fseek(&pb, 0, SEEK_SET);
178 if (ff_rm_read_mdpr_codecdata(rdt->rmctx, &pb, st, rdt->rmst[0], size) < 0)
185 * Actual data handling.
189 ff_rdt_parse_header(const uint8_t *buf, int len,
190 int *pset_id, int *pseq_no, int *pstream_id,
191 int *pis_keyframe, uint32_t *ptimestamp)
194 int consumed = 0, set_id, seq_no, stream_id, is_keyframe,
195 len_included, need_reliable;
198 /* skip status packets */
199 while (len >= 5 && buf[1] == 0xFF /* status packet */) {
202 if (!(buf[0] & 0x80))
203 return -1; /* not followed by a data packet */
205 pkt_len = AV_RB16(buf+3);
213 * Layout of the header (in bits):
215 * Flag indicating whether this header includes a length field;
216 * this can be used to concatenate multiple RDT packets in a
217 * single UDP/TCP data frame and is used to precede RDT data
218 * by stream status packets
220 * Flag indicating whether this header includes a "reliable
221 * sequence number"; these are apparently sequence numbers of
222 * data packets alone. For data packets, this flag is always
223 * set, according to the Real documentation [1]
225 * ID of a set of streams of identical content, possibly with
226 * different codecs or bitrates
228 * Flag set for certain streams deemed less tolerable for packet
231 * Packet sequence number; if >=0xFF00, this is a non-data packet
232 * containing stream status info, the second byte indicates the
233 * type of status packet (see wireshark docs / source code [2])
234 * if (len_included) {
237 * packet_len = remainder of UDP/TCP frame
240 * Back-to-Back flag; used for timing, set for one in every 10
241 * packets, according to the Real documentation [1]
243 * Slow-data flag; currently unused, according to Real docs [1]
245 * ID of the stream within this particular set of streams
247 * Non-keyframe flag (unset if packet belongs to a keyframe)
248 * 32: timestamp (PTS)
249 * if (set_id == 0x1F) {
250 * 16: set_id (extended set-of-streams ID; see set_id)
252 * if (need_reliable) {
253 * 16: reliable_seq_no
254 * Reliable sequence number (see need_reliable)
256 * if (stream_id == 0x3F) {
257 * 16: stream_id (extended stream ID; see stream_id)
259 * [1] https://protocol.helixcommunity.org/files/2005/devdocs/RDT_Feature_Level_20.txt
260 * [2] http://www.wireshark.org/docs/dfref/r/rdt.html and
261 * http://anonsvn.wireshark.org/viewvc/trunk/epan/dissectors/packet-rdt.c
263 init_get_bits(&gb, buf, len << 3);
264 len_included = get_bits1(&gb);
265 need_reliable = get_bits1(&gb);
266 set_id = get_bits(&gb, 5);
268 seq_no = get_bits(&gb, 16);
272 stream_id = get_bits(&gb, 5);
273 is_keyframe = !get_bits1(&gb);
274 timestamp = get_bits_long(&gb, 32);
276 set_id = get_bits(&gb, 16);
279 if (stream_id == 0x1f)
280 stream_id = get_bits(&gb, 16);
282 if (pset_id) *pset_id = set_id;
283 if (pseq_no) *pseq_no = seq_no;
284 if (pstream_id) *pstream_id = stream_id;
285 if (pis_keyframe) *pis_keyframe = is_keyframe;
286 if (ptimestamp) *ptimestamp = timestamp;
288 return consumed + (get_bits_count(&gb) >> 3);
291 /**< return 0 on packet, no more left, 1 on packet, 1 on partial packet... */
293 rdt_parse_packet (PayloadContext *rdt, AVStream *st,
294 AVPacket *pkt, uint32_t *timestamp,
295 const uint8_t *buf, int len, int flags)
300 if (rdt->audio_pkt_cnt == 0) {
303 init_put_byte(&pb, buf, len, 0, NULL, NULL, NULL, NULL);
304 flags = (flags & PKT_FLAG_KEY) ? 2 : 0;
305 res = ff_rm_parse_packet (rdt->rmctx, &pb, st, rdt->rmst[0], len, pkt,
306 &seq, &flags, timestamp);
307 pos = url_ftell(&pb);
310 rdt->audio_pkt_cnt = res;
311 if (rdt->audio_pkt_cnt > 0 &&
312 st->codec->codec_id == CODEC_ID_AAC) {
313 memcpy (rdt->buffer, buf + pos, len - pos);
314 rdt->rmctx->pb = av_alloc_put_byte (rdt->buffer, len - pos, 0,
315 NULL, NULL, NULL, NULL);
319 ff_rm_retrieve_cache (rdt->rmctx, rdt->rmctx->pb,
320 st, rdt->rmst[0], pkt);
321 if (rdt->audio_pkt_cnt == 0 &&
322 st->codec->codec_id == CODEC_ID_AAC)
323 av_freep(&rdt->rmctx->pb);
325 pkt->stream_index = st->index;
326 pkt->pts = *timestamp;
328 return rdt->audio_pkt_cnt > 0;
332 ff_rdt_parse_packet(RDTDemuxContext *s, AVPacket *pkt,
333 const uint8_t *buf, int len)
335 int seq_no, flags = 0, stream_id, set_id, is_keyframe;
339 if (!s->parse_packet)
342 if (!buf && s->prev_stream_id != -1) {
343 /* return the next packets, if any */
344 timestamp= 0; ///< Should not be used if buf is NULL, but should be set to the timestamp of the packet returned....
345 rv= s->parse_packet(s->dynamic_protocol_context,
346 s->streams[s->prev_stream_id],
347 pkt, ×tamp, NULL, 0, flags);
353 rv = ff_rdt_parse_header(buf, len, &set_id, &seq_no, &stream_id, &is_keyframe, ×tamp);
357 (set_id != s->prev_set_id || timestamp != s->prev_timestamp ||
358 stream_id != s->prev_stream_id)) {
359 flags |= PKT_FLAG_KEY;
360 s->prev_set_id = set_id;
361 s->prev_timestamp = timestamp;
363 s->prev_stream_id = stream_id;
367 if (s->prev_stream_id >= s->n_streams) {
368 s->prev_stream_id = -1;
372 rv = s->parse_packet(s->dynamic_protocol_context,
373 s->streams[s->prev_stream_id],
374 pkt, ×tamp, buf, len, flags);
380 ff_rdt_subscribe_rule (char *cmd, int size,
381 int stream_nr, int rule_nr)
383 av_strlcatf(cmd, size, "stream=%d;rule=%d,stream=%d;rule=%d",
384 stream_nr, rule_nr * 2, stream_nr, rule_nr * 2 + 1);
388 ff_rdt_subscribe_rule2 (RDTDemuxContext *s, char *cmd, int size,
389 int stream_nr, int rule_nr)
391 PayloadContext *rdt = s->dynamic_protocol_context;
393 rdt_load_mdpr(rdt, s->streams[0], rule_nr * 2);
396 static unsigned char *
397 rdt_parse_b64buf (unsigned int *target_len, const char *p)
399 unsigned char *target;
403 len -= 2; /* skip embracing " at start/end */
405 *target_len = len * 3 / 4;
406 target = av_mallocz(*target_len + FF_INPUT_BUFFER_PADDING_SIZE);
407 av_base64_decode(target, p, *target_len);
412 rdt_parse_sdp_line (AVFormatContext *s, int st_index,
413 PayloadContext *rdt, const char *line)
415 AVStream *stream = s->streams[st_index];
416 const char *p = line;
418 if (av_strstart(p, "OpaqueData:buffer;", &p)) {
419 rdt->mlti_data = rdt_parse_b64buf(&rdt->mlti_data_size, p);
420 } else if (av_strstart(p, "StartTime:integer;", &p))
421 stream->first_dts = atoi(p);
426 static PayloadContext *
427 rdt_new_extradata (void)
429 PayloadContext *rdt = av_mallocz(sizeof(PayloadContext));
431 av_open_input_stream(&rdt->rmctx, NULL, "", &rdt_demuxer, NULL);
432 rdt->rmst[0] = ff_rm_alloc_rmstream();
438 rdt_free_extradata (PayloadContext *rdt)
440 ff_rm_free_rmstream(rdt->rmst[0]);
442 av_close_input_stream(rdt->rmctx);
443 av_freep(&rdt->mlti_data);
447 #define RDT_HANDLER(n, s, t) \
448 static RTPDynamicProtocolHandler ff_rdt_ ## n ## _handler = { \
452 rdt_parse_sdp_line, \
454 rdt_free_extradata, \
458 RDT_HANDLER(live_video, "x-pn-multirate-realvideo-live", CODEC_TYPE_VIDEO);
459 RDT_HANDLER(live_audio, "x-pn-multirate-realaudio-live", CODEC_TYPE_AUDIO);
460 RDT_HANDLER(video, "x-pn-realvideo", CODEC_TYPE_VIDEO);
461 RDT_HANDLER(audio, "x-pn-realaudio", CODEC_TYPE_AUDIO);
463 void av_register_rdt_dynamic_payload_handlers(void)
465 ff_register_dynamic_payload_handler(&ff_rdt_video_handler);
466 ff_register_dynamic_payload_handler(&ff_rdt_audio_handler);
467 ff_register_dynamic_payload_handler(&ff_rdt_live_video_handler);
468 ff_register_dynamic_payload_handler(&ff_rdt_live_audio_handler);