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;
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_timestamp = -1;
69 s->parse_packet = handler->parse_packet;
70 s->dynamic_protocol_context = priv_data;
76 ff_rdt_parse_close(RDTDemuxContext *s)
81 struct PayloadContext {
82 AVFormatContext *rmctx;
84 unsigned int mlti_data_size;
85 char buffer[RTP_MAX_PACKET_LENGTH + FF_INPUT_BUFFER_PADDING_SIZE];
89 ff_rdt_calc_response_and_checksum(char response[41], char chksum[9],
90 const char *challenge)
92 int ch_len = strlen (challenge), i;
93 unsigned char zres[16],
94 buf[64] = { 0xa1, 0xe9, 0x14, 0x9d, 0x0e, 0x6b, 0x3b, 0x59 };
95 #define XOR_TABLE_SIZE 37
96 const unsigned char xor_table[XOR_TABLE_SIZE] = {
97 0x05, 0x18, 0x74, 0xd0, 0x0d, 0x09, 0x02, 0x53,
98 0xc0, 0x01, 0x05, 0x05, 0x67, 0x03, 0x19, 0x70,
99 0x08, 0x27, 0x66, 0x10, 0x10, 0x72, 0x08, 0x09,
100 0x63, 0x11, 0x03, 0x71, 0x08, 0x08, 0x70, 0x02,
101 0x10, 0x57, 0x05, 0x18, 0x54 };
103 /* some (length) checks */
104 if (ch_len == 40) /* what a hack... */
106 else if (ch_len > 56)
108 memcpy(buf + 8, challenge, ch_len);
110 /* xor challenge bytewise with xor_table */
111 for (i = 0; i < XOR_TABLE_SIZE; i++)
112 buf[8 + i] ^= xor_table[i];
114 av_md5_sum(zres, buf, 64);
115 ff_data_to_hex(response, zres, 16);
116 for (i=0;i<32;i++) response[i] = tolower(response[i]);
119 strcpy (response + 32, "01d0a8e3");
121 /* calculate checksum */
122 for (i = 0; i < 8; i++)
123 chksum[i] = response[i * 4];
128 rdt_load_mdpr (PayloadContext *rdt, AVStream *st, int rule_nr)
135 * Layout of the MLTI chunk:
137 * 2:<number of streams>
138 * Then for each stream ([number_of_streams] times):
140 * 2:<number of mdpr chunks>
141 * Then for each mdpr chunk ([number_of_mdpr_chunks] times):
144 * we skip MDPR chunks until we reach the one of the stream
145 * we're interested in, and forward that ([size]+[data]) to
146 * the RM demuxer to parse the stream-specific header data.
150 init_put_byte(&pb, rdt->mlti_data, rdt->mlti_data_size, 0,
151 NULL, NULL, NULL, NULL);
153 if (tag == MKTAG('M', 'L', 'T', 'I')) {
156 /* read index of MDPR chunk numbers */
158 if (rule_nr < 0 || rule_nr >= num)
160 url_fskip(&pb, rule_nr * 2);
161 chunk_nr = get_be16(&pb);
162 url_fskip(&pb, (num - 1 - rule_nr) * 2);
164 /* read MDPR chunks */
169 url_fskip(&pb, get_be32(&pb));
170 size = get_be32(&pb);
172 size = rdt->mlti_data_size;
173 url_fseek(&pb, 0, SEEK_SET);
175 if (ff_rm_read_mdpr_codecdata(rdt->rmctx, &pb, st, size) < 0)
182 * Actual data handling.
186 ff_rdt_parse_header(const uint8_t *buf, int len,
187 int *pset_id, int *pseq_no, int *pstream_id,
188 int *pis_keyframe, uint32_t *ptimestamp)
191 int consumed = 0, set_id, seq_no, stream_id, is_keyframe,
192 len_included, need_reliable;
195 /* skip status packets */
196 while (len >= 5 && buf[1] == 0xFF /* status packet */) {
199 if (!(buf[0] & 0x80))
200 return -1; /* not followed by a data packet */
202 pkt_len = AV_RB16(buf+3);
210 * Layout of the header (in bits):
212 * Flag indicating whether this header includes a length field;
213 * this can be used to concatenate multiple RDT packets in a
214 * single UDP/TCP data frame and is used to precede RDT data
215 * by stream status packets
217 * Flag indicating whether this header includes a "reliable
218 * sequence number"; these are apparently sequence numbers of
219 * data packets alone. For data packets, this flag is always
220 * set, according to the Real documentation [1]
222 * ID of a set of streams of identical content, possibly with
223 * different codecs or bitrates
225 * Flag set for certain streams deemed less tolerable for packet
228 * Packet sequence number; if >=0xFF00, this is a non-data packet
229 * containing stream status info, the second byte indicates the
230 * type of status packet (see wireshark docs / source code [2])
231 * if (len_included) {
234 * packet_len = remainder of UDP/TCP frame
237 * Back-to-Back flag; used for timing, set for one in every 10
238 * packets, according to the Real documentation [1]
240 * Slow-data flag; currently unused, according to Real docs [1]
242 * ID of the stream within this particular set of streams
244 * Non-keyframe flag (unset if packet belongs to a keyframe)
245 * 32: timestamp (PTS)
246 * if (set_id == 0x1F) {
247 * 16: set_id (extended set-of-streams ID; see set_id)
249 * if (need_reliable) {
250 * 16: reliable_seq_no
251 * Reliable sequence number (see need_reliable)
253 * if (stream_id == 0x3F) {
254 * 16: stream_id (extended stream ID; see stream_id)
256 * [1] https://protocol.helixcommunity.org/files/2005/devdocs/RDT_Feature_Level_20.txt
257 * [2] http://www.wireshark.org/docs/dfref/r/rdt.html and
258 * http://anonsvn.wireshark.org/viewvc/trunk/epan/dissectors/packet-rdt.c
260 init_get_bits(&gb, buf, len << 3);
261 len_included = get_bits1(&gb);
262 need_reliable = get_bits1(&gb);
263 set_id = get_bits(&gb, 5);
265 seq_no = get_bits(&gb, 16);
269 stream_id = get_bits(&gb, 5);
270 is_keyframe = !get_bits1(&gb);
271 timestamp = get_bits_long(&gb, 32);
273 set_id = get_bits(&gb, 16);
276 if (stream_id == 0x1f)
277 stream_id = get_bits(&gb, 16);
279 if (pset_id) *pset_id = set_id;
280 if (pseq_no) *pseq_no = seq_no;
281 if (pstream_id) *pstream_id = stream_id;
282 if (pis_keyframe) *pis_keyframe = is_keyframe;
283 if (ptimestamp) *ptimestamp = timestamp;
285 return consumed + (get_bits_count(&gb) >> 3);
288 /**< return 0 on packet, no more left, 1 on packet, 1 on partial packet... */
290 rdt_parse_packet (PayloadContext *rdt, AVStream *st,
291 AVPacket *pkt, uint32_t *timestamp,
292 const uint8_t *buf, int len, int flags)
296 RMContext *rm = rdt->rmctx->priv_data;
298 if (rm->audio_pkt_cnt == 0) {
301 init_put_byte(&pb, buf, len, 0, NULL, NULL, NULL, NULL);
302 flags = (flags & PKT_FLAG_KEY) ? 2 : 0;
303 res = ff_rm_parse_packet (rdt->rmctx, &pb, st, len, pkt,
304 &seq, &flags, timestamp);
305 pos = url_ftell(&pb);
308 if (rm->audio_pkt_cnt > 0 &&
309 st->codec->codec_id == CODEC_ID_AAC) {
310 memcpy (rdt->buffer, buf + pos, len - pos);
311 rdt->rmctx->pb = av_alloc_put_byte (rdt->buffer, len - pos, 0,
312 NULL, NULL, NULL, NULL);
315 ff_rm_retrieve_cache (rdt->rmctx, rdt->rmctx->pb, st, pkt);
316 if (rm->audio_pkt_cnt == 0 &&
317 st->codec->codec_id == CODEC_ID_AAC)
318 av_freep(&rdt->rmctx->pb);
320 pkt->stream_index = st->index;
321 pkt->pts = *timestamp;
323 return rm->audio_pkt_cnt > 0;
327 ff_rdt_parse_packet(RDTDemuxContext *s, AVPacket *pkt,
328 const uint8_t *buf, int len)
330 int seq_no, flags = 0, stream_id, set_id, is_keyframe;
334 if (!s->parse_packet)
338 /* return the next packets, if any */
339 timestamp= 0; ///< Should not be used if buf is NULL, but should be set to the timestamp of the packet returned....
340 rv= s->parse_packet(s->dynamic_protocol_context,
341 s->streams[0], pkt, ×tamp, NULL, 0, flags);
347 rv = ff_rdt_parse_header(buf, len, &set_id, &seq_no, &stream_id, &is_keyframe, ×tamp);
350 if (is_keyframe && (set_id != s->prev_set_id || timestamp != s->prev_timestamp)) {
351 flags |= PKT_FLAG_KEY;
352 s->prev_set_id = set_id;
353 s->prev_timestamp = timestamp;
358 rv = s->parse_packet(s->dynamic_protocol_context,
359 s->streams[0], pkt, ×tamp, buf, len, flags);
365 ff_rdt_subscribe_rule (char *cmd, int size,
366 int stream_nr, int rule_nr)
368 av_strlcatf(cmd, size, "stream=%d;rule=%d,stream=%d;rule=%d",
369 stream_nr, rule_nr * 2, stream_nr, rule_nr * 2 + 1);
373 ff_rdt_subscribe_rule2 (RDTDemuxContext *s, char *cmd, int size,
374 int stream_nr, int rule_nr)
376 PayloadContext *rdt = s->dynamic_protocol_context;
378 rdt_load_mdpr(rdt, s->streams[0], rule_nr * 2);
381 static unsigned char *
382 rdt_parse_b64buf (unsigned int *target_len, const char *p)
384 unsigned char *target;
388 len -= 2; /* skip embracing " at start/end */
390 *target_len = len * 3 / 4;
391 target = av_mallocz(*target_len + FF_INPUT_BUFFER_PADDING_SIZE);
392 av_base64_decode(target, p, *target_len);
397 rdt_parse_sdp_line (AVStream *stream, PayloadContext *rdt, const char *line)
399 const char *p = line;
401 if (av_strstart(p, "OpaqueData:buffer;", &p)) {
402 rdt->mlti_data = rdt_parse_b64buf(&rdt->mlti_data_size, p);
403 } else if (av_strstart(p, "StartTime:integer;", &p))
404 stream->first_dts = atoi(p);
409 static PayloadContext *
410 rdt_new_extradata (void)
412 PayloadContext *rdt = av_mallocz(sizeof(PayloadContext));
414 av_open_input_stream(&rdt->rmctx, NULL, "", &rdt_demuxer, NULL);
420 rdt_free_extradata (PayloadContext *rdt)
423 av_close_input_stream(rdt->rmctx);
424 av_freep(&rdt->mlti_data);
428 #define RDT_HANDLER(n, s, t) \
429 static RTPDynamicProtocolHandler ff_rdt_ ## n ## _handler = { \
433 rdt_parse_sdp_line, \
435 rdt_free_extradata, \
439 RDT_HANDLER(live_video, "x-pn-multirate-realvideo-live", CODEC_TYPE_VIDEO);
440 RDT_HANDLER(live_audio, "x-pn-multirate-realaudio-live", CODEC_TYPE_AUDIO);
441 RDT_HANDLER(video, "x-pn-realvideo", CODEC_TYPE_VIDEO);
442 RDT_HANDLER(audio, "x-pn-realaudio", CODEC_TYPE_AUDIO);
444 void av_register_rdt_dynamic_payload_handlers(void)
446 ff_register_dynamic_payload_handler(&ff_rdt_video_handler);
447 ff_register_dynamic_payload_handler(&ff_rdt_audio_handler);
448 ff_register_dynamic_payload_handler(&ff_rdt_live_video_handler);
449 ff_register_dynamic_payload_handler(&ff_rdt_live_audio_handler);