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];
87 int audio_pkt_cnt[MAX_STREAMS]; /**< remaining audio packets in rmdec */
91 ff_rdt_calc_response_and_checksum(char response[41], char chksum[9],
92 const char *challenge)
94 int ch_len = strlen (challenge), i;
95 unsigned char zres[16],
96 buf[64] = { 0xa1, 0xe9, 0x14, 0x9d, 0x0e, 0x6b, 0x3b, 0x59 };
97 #define XOR_TABLE_SIZE 37
98 const unsigned char xor_table[XOR_TABLE_SIZE] = {
99 0x05, 0x18, 0x74, 0xd0, 0x0d, 0x09, 0x02, 0x53,
100 0xc0, 0x01, 0x05, 0x05, 0x67, 0x03, 0x19, 0x70,
101 0x08, 0x27, 0x66, 0x10, 0x10, 0x72, 0x08, 0x09,
102 0x63, 0x11, 0x03, 0x71, 0x08, 0x08, 0x70, 0x02,
103 0x10, 0x57, 0x05, 0x18, 0x54 };
105 /* some (length) checks */
106 if (ch_len == 40) /* what a hack... */
108 else if (ch_len > 56)
110 memcpy(buf + 8, challenge, ch_len);
112 /* xor challenge bytewise with xor_table */
113 for (i = 0; i < XOR_TABLE_SIZE; i++)
114 buf[8 + i] ^= xor_table[i];
116 av_md5_sum(zres, buf, 64);
117 ff_data_to_hex(response, zres, 16);
118 for (i=0;i<32;i++) response[i] = tolower(response[i]);
121 strcpy (response + 32, "01d0a8e3");
123 /* calculate checksum */
124 for (i = 0; i < 8; i++)
125 chksum[i] = response[i * 4];
130 rdt_load_mdpr (PayloadContext *rdt, AVStream *st, int rule_nr)
137 * Layout of the MLTI chunk:
139 * 2:<number of streams>
140 * Then for each stream ([number_of_streams] times):
142 * 2:<number of mdpr chunks>
143 * Then for each mdpr chunk ([number_of_mdpr_chunks] times):
146 * we skip MDPR chunks until we reach the one of the stream
147 * we're interested in, and forward that ([size]+[data]) to
148 * the RM demuxer to parse the stream-specific header data.
152 init_put_byte(&pb, rdt->mlti_data, rdt->mlti_data_size, 0,
153 NULL, NULL, NULL, NULL);
155 if (tag == MKTAG('M', 'L', 'T', 'I')) {
158 /* read index of MDPR chunk numbers */
160 if (rule_nr < 0 || rule_nr >= num)
162 url_fskip(&pb, rule_nr * 2);
163 chunk_nr = get_be16(&pb);
164 url_fskip(&pb, (num - 1 - rule_nr) * 2);
166 /* read MDPR chunks */
171 url_fskip(&pb, get_be32(&pb));
172 size = get_be32(&pb);
174 size = rdt->mlti_data_size;
175 url_fseek(&pb, 0, SEEK_SET);
177 if (ff_rm_read_mdpr_codecdata(rdt->rmctx, &pb, st, size) < 0)
184 * Actual data handling.
188 ff_rdt_parse_header(const uint8_t *buf, int len,
189 int *pset_id, int *pseq_no, int *pstream_id,
190 int *pis_keyframe, uint32_t *ptimestamp)
193 int consumed = 0, set_id, seq_no, stream_id, is_keyframe,
194 len_included, need_reliable;
197 /* skip status packets */
198 while (len >= 5 && buf[1] == 0xFF /* status packet */) {
201 if (!(buf[0] & 0x80))
202 return -1; /* not followed by a data packet */
204 pkt_len = AV_RB16(buf+3);
212 * Layout of the header (in bits):
214 * Flag indicating whether this header includes a length field;
215 * this can be used to concatenate multiple RDT packets in a
216 * single UDP/TCP data frame and is used to precede RDT data
217 * by stream status packets
219 * Flag indicating whether this header includes a "reliable
220 * sequence number"; these are apparently sequence numbers of
221 * data packets alone. For data packets, this flag is always
222 * set, according to the Real documentation [1]
224 * ID of a set of streams of identical content, possibly with
225 * different codecs or bitrates
227 * Flag set for certain streams deemed less tolerable for packet
230 * Packet sequence number; if >=0xFF00, this is a non-data packet
231 * containing stream status info, the second byte indicates the
232 * type of status packet (see wireshark docs / source code [2])
233 * if (len_included) {
236 * packet_len = remainder of UDP/TCP frame
239 * Back-to-Back flag; used for timing, set for one in every 10
240 * packets, according to the Real documentation [1]
242 * Slow-data flag; currently unused, according to Real docs [1]
244 * ID of the stream within this particular set of streams
246 * Non-keyframe flag (unset if packet belongs to a keyframe)
247 * 32: timestamp (PTS)
248 * if (set_id == 0x1F) {
249 * 16: set_id (extended set-of-streams ID; see set_id)
251 * if (need_reliable) {
252 * 16: reliable_seq_no
253 * Reliable sequence number (see need_reliable)
255 * if (stream_id == 0x3F) {
256 * 16: stream_id (extended stream ID; see stream_id)
258 * [1] https://protocol.helixcommunity.org/files/2005/devdocs/RDT_Feature_Level_20.txt
259 * [2] http://www.wireshark.org/docs/dfref/r/rdt.html and
260 * http://anonsvn.wireshark.org/viewvc/trunk/epan/dissectors/packet-rdt.c
262 init_get_bits(&gb, buf, len << 3);
263 len_included = get_bits1(&gb);
264 need_reliable = get_bits1(&gb);
265 set_id = get_bits(&gb, 5);
267 seq_no = get_bits(&gb, 16);
271 stream_id = get_bits(&gb, 5);
272 is_keyframe = !get_bits1(&gb);
273 timestamp = get_bits_long(&gb, 32);
275 set_id = get_bits(&gb, 16);
278 if (stream_id == 0x1f)
279 stream_id = get_bits(&gb, 16);
281 if (pset_id) *pset_id = set_id;
282 if (pseq_no) *pseq_no = seq_no;
283 if (pstream_id) *pstream_id = stream_id;
284 if (pis_keyframe) *pis_keyframe = is_keyframe;
285 if (ptimestamp) *ptimestamp = timestamp;
287 return consumed + (get_bits_count(&gb) >> 3);
290 /**< return 0 on packet, no more left, 1 on packet, 1 on partial packet... */
292 rdt_parse_packet (PayloadContext *rdt, AVStream *st,
293 AVPacket *pkt, uint32_t *timestamp,
294 const uint8_t *buf, int len, int flags)
299 if (rdt->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 rdt->audio_pkt_cnt[st->id] = res;
310 if (rdt->audio_pkt_cnt[st->id] > 0 &&
311 st->codec->codec_id == CODEC_ID_AAC) {
312 memcpy (rdt->buffer, buf + pos, len - pos);
313 rdt->rmctx->pb = av_alloc_put_byte (rdt->buffer, len - pos, 0,
314 NULL, NULL, NULL, NULL);
317 ff_rm_retrieve_cache (rdt->rmctx, rdt->rmctx->pb, st, pkt);
318 if (rdt->audio_pkt_cnt[st->id] == 0 &&
319 st->codec->codec_id == CODEC_ID_AAC)
320 av_freep(&rdt->rmctx->pb);
322 pkt->stream_index = st->index;
323 pkt->pts = *timestamp;
325 return rdt->audio_pkt_cnt[st->id] > 0;
329 ff_rdt_parse_packet(RDTDemuxContext *s, AVPacket *pkt,
330 const uint8_t *buf, int len)
332 int seq_no, flags = 0, stream_id, set_id, is_keyframe;
336 if (!s->parse_packet)
339 if (!buf && s->prev_stream_id != -1) {
340 /* return the next packets, if any */
341 timestamp= 0; ///< Should not be used if buf is NULL, but should be set to the timestamp of the packet returned....
342 rv= s->parse_packet(s->dynamic_protocol_context,
343 s->streams[s->prev_stream_id],
344 pkt, ×tamp, NULL, 0, flags);
350 rv = ff_rdt_parse_header(buf, len, &set_id, &seq_no, &stream_id, &is_keyframe, ×tamp);
354 (set_id != s->prev_set_id || timestamp != s->prev_timestamp ||
355 stream_id != s->prev_stream_id)) {
356 flags |= PKT_FLAG_KEY;
357 s->prev_set_id = set_id;
358 s->prev_timestamp = timestamp;
360 s->prev_stream_id = stream_id;
364 if (s->prev_stream_id >= s->n_streams) {
365 s->prev_stream_id = -1;
369 rv = s->parse_packet(s->dynamic_protocol_context,
370 s->streams[s->prev_stream_id],
371 pkt, ×tamp, buf, len, flags);
377 ff_rdt_subscribe_rule (char *cmd, int size,
378 int stream_nr, int rule_nr)
380 av_strlcatf(cmd, size, "stream=%d;rule=%d,stream=%d;rule=%d",
381 stream_nr, rule_nr * 2, stream_nr, rule_nr * 2 + 1);
385 ff_rdt_subscribe_rule2 (RDTDemuxContext *s, char *cmd, int size,
386 int stream_nr, int rule_nr)
388 PayloadContext *rdt = s->dynamic_protocol_context;
390 rdt_load_mdpr(rdt, s->streams[0], rule_nr * 2);
393 static unsigned char *
394 rdt_parse_b64buf (unsigned int *target_len, const char *p)
396 unsigned char *target;
400 len -= 2; /* skip embracing " at start/end */
402 *target_len = len * 3 / 4;
403 target = av_mallocz(*target_len + FF_INPUT_BUFFER_PADDING_SIZE);
404 av_base64_decode(target, p, *target_len);
409 rdt_parse_sdp_line (AVFormatContext *s, int st_index,
410 PayloadContext *rdt, const char *line)
412 AVStream *stream = s->streams[st_index];
413 const char *p = line;
415 if (av_strstart(p, "OpaqueData:buffer;", &p)) {
416 rdt->mlti_data = rdt_parse_b64buf(&rdt->mlti_data_size, p);
417 } else if (av_strstart(p, "StartTime:integer;", &p))
418 stream->first_dts = atoi(p);
423 static PayloadContext *
424 rdt_new_extradata (void)
426 PayloadContext *rdt = av_mallocz(sizeof(PayloadContext));
428 av_open_input_stream(&rdt->rmctx, NULL, "", &rdt_demuxer, NULL);
434 rdt_free_extradata (PayloadContext *rdt)
437 av_close_input_stream(rdt->rmctx);
438 av_freep(&rdt->mlti_data);
442 #define RDT_HANDLER(n, s, t) \
443 static RTPDynamicProtocolHandler ff_rdt_ ## n ## _handler = { \
447 rdt_parse_sdp_line, \
449 rdt_free_extradata, \
453 RDT_HANDLER(live_video, "x-pn-multirate-realvideo-live", CODEC_TYPE_VIDEO);
454 RDT_HANDLER(live_audio, "x-pn-multirate-realaudio-live", CODEC_TYPE_AUDIO);
455 RDT_HANDLER(video, "x-pn-realvideo", CODEC_TYPE_VIDEO);
456 RDT_HANDLER(audio, "x-pn-realaudio", CODEC_TYPE_AUDIO);
458 void av_register_rdt_dynamic_payload_handlers(void)
460 ff_register_dynamic_payload_handler(&ff_rdt_video_handler);
461 ff_register_dynamic_payload_handler(&ff_rdt_audio_handler);
462 ff_register_dynamic_payload_handler(&ff_rdt_live_video_handler);
463 ff_register_dynamic_payload_handler(&ff_rdt_live_audio_handler);