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sdp.c
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1 /*
2  * copyright (c) 2007 Luca Abeni
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #include <string.h>
22 #include "libavutil/avstring.h"
23 #include "libavutil/base64.h"
24 #include "libavutil/dict.h"
25 #include "libavutil/parseutils.h"
26 #include "libavutil/opt.h"
27 #include "libavcodec/xiph.h"
28 #include "libavcodec/mpeg4audio.h"
29 #include "avformat.h"
30 #include "internal.h"
31 #include "avc.h"
32 #include "rtp.h"
33 #if CONFIG_NETWORK
34 #include "network.h"
35 #endif
36 
37 #if CONFIG_RTP_MUXER
38 #define MAX_EXTRADATA_SIZE ((INT_MAX - 10) / 2)
39 
40 struct sdp_session_level {
41  int sdp_version; /**< protocol version (currently 0) */
42  int id; /**< session ID */
43  int version; /**< session version */
44  int start_time; /**< session start time (NTP time, in seconds),
45  or 0 in case of permanent session */
46  int end_time; /**< session end time (NTP time, in seconds),
47  or 0 if the session is not bounded */
48  int ttl; /**< TTL, in case of multicast stream */
49  const char *user; /**< username of the session's creator */
50  const char *src_addr; /**< IP address of the machine from which the session was created */
51  const char *src_type; /**< address type of src_addr */
52  const char *dst_addr; /**< destination IP address (can be multicast) */
53  const char *dst_type; /**< destination IP address type */
54  const char *name; /**< session name (can be an empty string) */
55 };
56 
57 static void sdp_write_address(char *buff, int size, const char *dest_addr,
58  const char *dest_type, int ttl)
59 {
60  if (dest_addr) {
61  if (!dest_type)
62  dest_type = "IP4";
63  if (ttl > 0 && !strcmp(dest_type, "IP4")) {
64  /* The TTL should only be specified for IPv4 multicast addresses,
65  * not for IPv6. */
66  av_strlcatf(buff, size, "c=IN %s %s/%d\r\n", dest_type, dest_addr, ttl);
67  } else {
68  av_strlcatf(buff, size, "c=IN %s %s\r\n", dest_type, dest_addr);
69  }
70  }
71 }
72 
73 static void sdp_write_header(char *buff, int size, struct sdp_session_level *s)
74 {
75  av_strlcatf(buff, size, "v=%d\r\n"
76  "o=- %d %d IN %s %s\r\n"
77  "s=%s\r\n",
78  s->sdp_version,
79  s->id, s->version, s->src_type, s->src_addr,
80  s->name);
81  sdp_write_address(buff, size, s->dst_addr, s->dst_type, s->ttl);
82  av_strlcatf(buff, size, "t=%d %d\r\n"
83  "a=tool:libavformat " AV_STRINGIFY(LIBAVFORMAT_VERSION) "\r\n",
84  s->start_time, s->end_time);
85 }
86 
87 #if CONFIG_NETWORK
88 static int resolve_destination(char *dest_addr, int size, char *type,
89  int type_size)
90 {
91  struct addrinfo hints = { 0 }, *ai;
92  int is_multicast;
93 
94  av_strlcpy(type, "IP4", type_size);
95  if (!dest_addr[0])
96  return 0;
97 
98  /* Resolve the destination, since it must be written
99  * as a numeric IP address in the SDP. */
100 
101  if (getaddrinfo(dest_addr, NULL, &hints, &ai))
102  return 0;
103  getnameinfo(ai->ai_addr, ai->ai_addrlen, dest_addr, size,
104  NULL, 0, NI_NUMERICHOST);
105 #ifdef AF_INET6
106  if (ai->ai_family == AF_INET6)
107  av_strlcpy(type, "IP6", type_size);
108 #endif
109  is_multicast = ff_is_multicast_address(ai->ai_addr);
110  freeaddrinfo(ai);
111  return is_multicast;
112 }
113 #else
114 static int resolve_destination(char *dest_addr, int size, char *type,
115  int type_size)
116 {
117  return 0;
118 }
119 #endif
120 
121 static int sdp_get_address(char *dest_addr, int size, int *ttl, const char *url)
122 {
123  int port;
124  const char *p;
125  char proto[32];
126 
127  av_url_split(proto, sizeof(proto), NULL, 0, dest_addr, size, &port, NULL, 0, url);
128 
129  *ttl = 0;
130 
131  if (strcmp(proto, "rtp") && strcmp(proto, "srtp")) {
132  /* The url isn't for the actual rtp sessions,
133  * don't parse out anything else than the destination.
134  */
135  return 0;
136  }
137 
138  p = strchr(url, '?');
139  if (p) {
140  char buff[64];
141 
142  if (av_find_info_tag(buff, sizeof(buff), "ttl", p)) {
143  *ttl = strtol(buff, NULL, 10);
144  } else {
145  *ttl = 5;
146  }
147  }
148 
149  return port;
150 }
151 
152 #define MAX_PSET_SIZE 1024
153 static char *extradata2psets(AVCodecContext *c)
154 {
155  char *psets, *p;
156  const uint8_t *r;
157  static const char pset_string[] = "; sprop-parameter-sets=";
158  static const char profile_string[] = "; profile-level-id=";
159  uint8_t *orig_extradata = NULL;
160  int orig_extradata_size = 0;
161  const uint8_t *sps = NULL, *sps_end;
162 
163  if (c->extradata_size > MAX_EXTRADATA_SIZE) {
164  av_log(c, AV_LOG_ERROR, "Too much extradata!\n");
165 
166  return NULL;
167  }
168  if (c->extradata[0] == 1) {
169  uint8_t *dummy_p;
170  int dummy_int;
171  AVBitStreamFilterContext *bsfc= av_bitstream_filter_init("h264_mp4toannexb");
172 
173  if (!bsfc) {
174  av_log(c, AV_LOG_ERROR, "Cannot open the h264_mp4toannexb BSF!\n");
175 
176  return NULL;
177  }
178 
179  orig_extradata_size = c->extradata_size;
180  orig_extradata = av_mallocz(orig_extradata_size +
181  FF_INPUT_BUFFER_PADDING_SIZE);
182  if (!orig_extradata) {
183  av_bitstream_filter_close(bsfc);
184  return NULL;
185  }
186  memcpy(orig_extradata, c->extradata, orig_extradata_size);
187  av_bitstream_filter_filter(bsfc, c, NULL, &dummy_p, &dummy_int, NULL, 0, 0);
188  av_bitstream_filter_close(bsfc);
189  }
190 
191  psets = av_mallocz(MAX_PSET_SIZE);
192  if (psets == NULL) {
193  av_log(c, AV_LOG_ERROR, "Cannot allocate memory for the parameter sets.\n");
194  av_free(orig_extradata);
195  return NULL;
196  }
197  memcpy(psets, pset_string, strlen(pset_string));
198  p = psets + strlen(pset_string);
199  r = ff_avc_find_startcode(c->extradata, c->extradata + c->extradata_size);
200  while (r < c->extradata + c->extradata_size) {
201  const uint8_t *r1;
202  uint8_t nal_type;
203 
204  while (!*(r++));
205  nal_type = *r & 0x1f;
206  r1 = ff_avc_find_startcode(r, c->extradata + c->extradata_size);
207  if (nal_type != 7 && nal_type != 8) { /* Only output SPS and PPS */
208  r = r1;
209  continue;
210  }
211  if (p != (psets + strlen(pset_string))) {
212  *p = ',';
213  p++;
214  }
215  if (!sps) {
216  sps = r;
217  sps_end = r1;
218  }
219  if (av_base64_encode(p, MAX_PSET_SIZE - (p - psets), r, r1 - r) == NULL) {
220  av_log(c, AV_LOG_ERROR, "Cannot Base64-encode %td %td!\n", MAX_PSET_SIZE - (p - psets), r1 - r);
221  av_free(psets);
222 
223  return NULL;
224  }
225  p += strlen(p);
226  r = r1;
227  }
228  if (sps && sps_end - sps >= 4) {
229  memcpy(p, profile_string, strlen(profile_string));
230  p += strlen(p);
231  ff_data_to_hex(p, sps + 1, 3, 0);
232  p[6] = '\0';
233  }
234  if (orig_extradata) {
235  av_free(c->extradata);
236  c->extradata = orig_extradata;
237  c->extradata_size = orig_extradata_size;
238  }
239 
240  return psets;
241 }
242 
243 static char *extradata2config(AVCodecContext *c)
244 {
245  char *config;
246 
247  if (c->extradata_size > MAX_EXTRADATA_SIZE) {
248  av_log(c, AV_LOG_ERROR, "Too much extradata!\n");
249 
250  return NULL;
251  }
252  config = av_malloc(10 + c->extradata_size * 2);
253  if (config == NULL) {
254  av_log(c, AV_LOG_ERROR, "Cannot allocate memory for the config info.\n");
255  return NULL;
256  }
257  memcpy(config, "; config=", 9);
258  ff_data_to_hex(config + 9, c->extradata, c->extradata_size, 0);
259  config[9 + c->extradata_size * 2] = 0;
260 
261  return config;
262 }
263 
264 static char *xiph_extradata2config(AVCodecContext *c)
265 {
266  char *config, *encoded_config;
267  uint8_t *header_start[3];
268  int headers_len, header_len[3], config_len;
269  int first_header_size;
270 
271  switch (c->codec_id) {
272  case AV_CODEC_ID_THEORA:
273  first_header_size = 42;
274  break;
275  case AV_CODEC_ID_VORBIS:
276  first_header_size = 30;
277  break;
278  default:
279  av_log(c, AV_LOG_ERROR, "Unsupported Xiph codec ID\n");
280  return NULL;
281  }
282 
283  if (avpriv_split_xiph_headers(c->extradata, c->extradata_size,
284  first_header_size, header_start,
285  header_len) < 0) {
286  av_log(c, AV_LOG_ERROR, "Extradata corrupt.\n");
287  return NULL;
288  }
289 
290  headers_len = header_len[0] + header_len[2];
291  config_len = 4 + // count
292  3 + // ident
293  2 + // packet size
294  1 + // header count
295  2 + // header size
296  headers_len; // and the rest
297 
298  config = av_malloc(config_len);
299  if (!config)
300  goto xiph_fail;
301 
302  encoded_config = av_malloc(AV_BASE64_SIZE(config_len));
303  if (!encoded_config) {
304  av_free(config);
305  goto xiph_fail;
306  }
307 
308  config[0] = config[1] = config[2] = 0;
309  config[3] = 1;
310  config[4] = (RTP_XIPH_IDENT >> 16) & 0xff;
311  config[5] = (RTP_XIPH_IDENT >> 8) & 0xff;
312  config[6] = (RTP_XIPH_IDENT ) & 0xff;
313  config[7] = (headers_len >> 8) & 0xff;
314  config[8] = headers_len & 0xff;
315  config[9] = 2;
316  config[10] = header_len[0];
317  config[11] = 0; // size of comment header; nonexistent
318  memcpy(config + 12, header_start[0], header_len[0]);
319  memcpy(config + 12 + header_len[0], header_start[2], header_len[2]);
320 
321  av_base64_encode(encoded_config, AV_BASE64_SIZE(config_len),
322  config, config_len);
323  av_free(config);
324 
325  return encoded_config;
326 
327 xiph_fail:
328  av_log(c, AV_LOG_ERROR,
329  "Not enough memory for configuration string\n");
330  return NULL;
331 }
332 
333 static int latm_context2profilelevel(AVCodecContext *c)
334 {
335  /* MP4A-LATM
336  * The RTP payload format specification is described in RFC 3016
337  * The encoding specifications are provided in ISO/IEC 14496-3 */
338 
339  int profile_level = 0x2B;
340 
341  /* TODO: AAC Profile only supports AAC LC Object Type.
342  * Different Object Types should implement different Profile Levels */
343 
344  if (c->sample_rate <= 24000) {
345  if (c->channels <= 2)
346  profile_level = 0x28; // AAC Profile, Level 1
347  } else if (c->sample_rate <= 48000) {
348  if (c->channels <= 2) {
349  profile_level = 0x29; // AAC Profile, Level 2
350  } else if (c->channels <= 5) {
351  profile_level = 0x2A; // AAC Profile, Level 4
352  }
353  } else if (c->sample_rate <= 96000) {
354  if (c->channels <= 5) {
355  profile_level = 0x2B; // AAC Profile, Level 5
356  }
357  }
358 
359  return profile_level;
360 }
361 
362 static char *latm_context2config(AVCodecContext *c)
363 {
364  /* MP4A-LATM
365  * The RTP payload format specification is described in RFC 3016
366  * The encoding specifications are provided in ISO/IEC 14496-3 */
367 
368  uint8_t config_byte[6];
369  int rate_index;
370  char *config;
371 
372  for (rate_index = 0; rate_index < 16; rate_index++)
373  if (avpriv_mpeg4audio_sample_rates[rate_index] == c->sample_rate)
374  break;
375  if (rate_index == 16) {
376  av_log(c, AV_LOG_ERROR, "Unsupported sample rate\n");
377  return NULL;
378  }
379 
380  config_byte[0] = 0x40;
381  config_byte[1] = 0;
382  config_byte[2] = 0x20 | rate_index;
383  config_byte[3] = c->channels << 4;
384  config_byte[4] = 0x3f;
385  config_byte[5] = 0xc0;
386 
387  config = av_malloc(6*2+1);
388  if (!config) {
389  av_log(c, AV_LOG_ERROR, "Cannot allocate memory for the config info.\n");
390  return NULL;
391  }
392  ff_data_to_hex(config, config_byte, 6, 1);
393  config[12] = 0;
394 
395  return config;
396 }
397 
398 static char *sdp_write_media_attributes(char *buff, int size, AVCodecContext *c, int payload_type, AVFormatContext *fmt)
399 {
400  char *config = NULL;
401 
402  switch (c->codec_id) {
403  case AV_CODEC_ID_H264: {
404  int mode = 1;
405  if (fmt && fmt->oformat && fmt->oformat->priv_class &&
406  av_opt_flag_is_set(fmt->priv_data, "rtpflags", "h264_mode0"))
407  mode = 0;
408  if (c->extradata_size) {
409  config = extradata2psets(c);
410  }
411  av_strlcatf(buff, size, "a=rtpmap:%d H264/90000\r\n"
412  "a=fmtp:%d packetization-mode=%d%s\r\n",
413  payload_type,
414  payload_type, mode, config ? config : "");
415  break;
416  }
417  case AV_CODEC_ID_H263:
418  case AV_CODEC_ID_H263P:
419  /* a=framesize is required by 3GPP TS 26.234 (PSS). It
420  * actually specifies the maximum video size, but we only know
421  * the current size. This is required for playback on Android
422  * stagefright and on Samsung bada. */
423  if (!fmt || !fmt->oformat->priv_class ||
424  !av_opt_flag_is_set(fmt->priv_data, "rtpflags", "rfc2190") ||
425  c->codec_id == AV_CODEC_ID_H263P)
426  av_strlcatf(buff, size, "a=rtpmap:%d H263-2000/90000\r\n"
427  "a=framesize:%d %d-%d\r\n",
428  payload_type,
429  payload_type, c->width, c->height);
430  break;
431  case AV_CODEC_ID_MPEG4:
432  if (c->extradata_size) {
433  config = extradata2config(c);
434  }
435  av_strlcatf(buff, size, "a=rtpmap:%d MP4V-ES/90000\r\n"
436  "a=fmtp:%d profile-level-id=1%s\r\n",
437  payload_type,
438  payload_type, config ? config : "");
439  break;
440  case AV_CODEC_ID_AAC:
441  if (fmt && fmt->oformat && fmt->oformat->priv_class &&
442  av_opt_flag_is_set(fmt->priv_data, "rtpflags", "latm")) {
443  config = latm_context2config(c);
444  if (!config)
445  return NULL;
446  av_strlcatf(buff, size, "a=rtpmap:%d MP4A-LATM/%d/%d\r\n"
447  "a=fmtp:%d profile-level-id=%d;cpresent=0;config=%s\r\n",
448  payload_type, c->sample_rate, c->channels,
449  payload_type, latm_context2profilelevel(c), config);
450  } else {
451  if (c->extradata_size) {
452  config = extradata2config(c);
453  } else {
454  /* FIXME: maybe we can forge config information based on the
455  * codec parameters...
456  */
457  av_log(c, AV_LOG_ERROR, "AAC with no global headers is currently not supported.\n");
458  return NULL;
459  }
460  if (config == NULL) {
461  return NULL;
462  }
463  av_strlcatf(buff, size, "a=rtpmap:%d MPEG4-GENERIC/%d/%d\r\n"
464  "a=fmtp:%d profile-level-id=1;"
465  "mode=AAC-hbr;sizelength=13;indexlength=3;"
466  "indexdeltalength=3%s\r\n",
467  payload_type, c->sample_rate, c->channels,
468  payload_type, config);
469  }
470  break;
471  case AV_CODEC_ID_PCM_S16BE:
472  if (payload_type >= RTP_PT_PRIVATE)
473  av_strlcatf(buff, size, "a=rtpmap:%d L16/%d/%d\r\n",
474  payload_type,
475  c->sample_rate, c->channels);
476  break;
477  case AV_CODEC_ID_PCM_MULAW:
478  if (payload_type >= RTP_PT_PRIVATE)
479  av_strlcatf(buff, size, "a=rtpmap:%d PCMU/%d/%d\r\n",
480  payload_type,
481  c->sample_rate, c->channels);
482  break;
483  case AV_CODEC_ID_PCM_ALAW:
484  if (payload_type >= RTP_PT_PRIVATE)
485  av_strlcatf(buff, size, "a=rtpmap:%d PCMA/%d/%d\r\n",
486  payload_type,
487  c->sample_rate, c->channels);
488  break;
489  case AV_CODEC_ID_AMR_NB:
490  av_strlcatf(buff, size, "a=rtpmap:%d AMR/%d/%d\r\n"
491  "a=fmtp:%d octet-align=1\r\n",
492  payload_type, c->sample_rate, c->channels,
493  payload_type);
494  break;
495  case AV_CODEC_ID_AMR_WB:
496  av_strlcatf(buff, size, "a=rtpmap:%d AMR-WB/%d/%d\r\n"
497  "a=fmtp:%d octet-align=1\r\n",
498  payload_type, c->sample_rate, c->channels,
499  payload_type);
500  break;
501  case AV_CODEC_ID_VORBIS:
502  if (c->extradata_size)
503  config = xiph_extradata2config(c);
504  else
505  av_log(c, AV_LOG_ERROR, "Vorbis configuration info missing\n");
506  if (!config)
507  return NULL;
508 
509  av_strlcatf(buff, size, "a=rtpmap:%d vorbis/%d/%d\r\n"
510  "a=fmtp:%d configuration=%s\r\n",
511  payload_type, c->sample_rate, c->channels,
512  payload_type, config);
513  break;
514  case AV_CODEC_ID_THEORA: {
515  const char *pix_fmt;
516  switch (c->pix_fmt) {
517  case AV_PIX_FMT_YUV420P:
518  pix_fmt = "YCbCr-4:2:0";
519  break;
520  case AV_PIX_FMT_YUV422P:
521  pix_fmt = "YCbCr-4:2:2";
522  break;
523  case AV_PIX_FMT_YUV444P:
524  pix_fmt = "YCbCr-4:4:4";
525  break;
526  default:
527  av_log(c, AV_LOG_ERROR, "Unsupported pixel format.\n");
528  return NULL;
529  }
530 
531  if (c->extradata_size)
532  config = xiph_extradata2config(c);
533  else
534  av_log(c, AV_LOG_ERROR, "Theora configuation info missing\n");
535  if (!config)
536  return NULL;
537 
538  av_strlcatf(buff, size, "a=rtpmap:%d theora/90000\r\n"
539  "a=fmtp:%d delivery-method=inline; "
540  "width=%d; height=%d; sampling=%s; "
541  "configuration=%s\r\n",
542  payload_type, payload_type,
543  c->width, c->height, pix_fmt, config);
544  break;
545  }
546  case AV_CODEC_ID_VP8:
547  av_strlcatf(buff, size, "a=rtpmap:%d VP8/90000\r\n",
548  payload_type);
549  break;
550  case AV_CODEC_ID_MJPEG:
551  if (payload_type >= RTP_PT_PRIVATE)
552  av_strlcatf(buff, size, "a=rtpmap:%d JPEG/90000\r\n",
553  payload_type);
554  break;
555  case AV_CODEC_ID_ADPCM_G722:
556  if (payload_type >= RTP_PT_PRIVATE)
557  av_strlcatf(buff, size, "a=rtpmap:%d G722/%d/%d\r\n",
558  payload_type,
559  8000, c->channels);
560  break;
561  case AV_CODEC_ID_ADPCM_G726: {
562  if (payload_type >= RTP_PT_PRIVATE)
563  av_strlcatf(buff, size, "a=rtpmap:%d G726-%d/%d\r\n",
564  payload_type,
565  c->bits_per_coded_sample*8,
566  c->sample_rate);
567  break;
568  }
569  case AV_CODEC_ID_ILBC:
570  av_strlcatf(buff, size, "a=rtpmap:%d iLBC/%d\r\n"
571  "a=fmtp:%d mode=%d\r\n",
572  payload_type, c->sample_rate,
573  payload_type, c->block_align == 38 ? 20 : 30);
574  break;
575  case AV_CODEC_ID_SPEEX:
576  av_strlcatf(buff, size, "a=rtpmap:%d speex/%d\r\n",
577  payload_type, c->sample_rate);
578  if (c->codec) {
579  const char *mode;
580  uint64_t vad_option;
581 
582  if (c->flags & CODEC_FLAG_QSCALE)
583  mode = "on";
584  else if (!av_opt_get_int(c, "vad", AV_OPT_FLAG_ENCODING_PARAM, &vad_option) && vad_option)
585  mode = "vad";
586  else
587  mode = "off";
588 
589  av_strlcatf(buff, size, "a=fmtp:%d vbr=%s\r\n",
590  payload_type, mode);
591  }
592  break;
593  case AV_CODEC_ID_OPUS:
594  av_strlcatf(buff, size, "a=rtpmap:%d opus/48000\r\n",
595  payload_type);
596  break;
597  default:
598  /* Nothing special to do here... */
599  break;
600  }
601 
602  av_free(config);
603 
604  return buff;
605 }
606 
607 void ff_sdp_write_media(char *buff, int size, AVStream *st, int idx,
608  const char *dest_addr, const char *dest_type,
609  int port, int ttl, AVFormatContext *fmt)
610 {
611  AVCodecContext *c = st->codec;
612  const char *type;
613  int payload_type;
614 
615  payload_type = ff_rtp_get_payload_type(fmt, c, idx);
616 
617  switch (c->codec_type) {
618  case AVMEDIA_TYPE_VIDEO : type = "video" ; break;
619  case AVMEDIA_TYPE_AUDIO : type = "audio" ; break;
620  case AVMEDIA_TYPE_SUBTITLE: type = "text" ; break;
621  default : type = "application"; break;
622  }
623 
624  av_strlcatf(buff, size, "m=%s %d RTP/AVP %d\r\n", type, port, payload_type);
625  sdp_write_address(buff, size, dest_addr, dest_type, ttl);
626  if (c->bit_rate) {
627  av_strlcatf(buff, size, "b=AS:%d\r\n", c->bit_rate / 1000);
628  }
629 
630  sdp_write_media_attributes(buff, size, c, payload_type, fmt);
631 }
632 
633 int av_sdp_create(AVFormatContext *ac[], int n_files, char *buf, int size)
634 {
635  AVDictionaryEntry *title = av_dict_get(ac[0]->metadata, "title", NULL, 0);
636  struct sdp_session_level s = { 0 };
637  int i, j, port, ttl, is_multicast, index = 0;
638  char dst[32], dst_type[5];
639 
640  memset(buf, 0, size);
641  s.user = "-";
642  s.src_addr = "127.0.0.1"; /* FIXME: Properly set this */
643  s.src_type = "IP4";
644  s.name = title ? title->value : "No Name";
645 
646  port = 0;
647  ttl = 0;
648  if (n_files == 1) {
649  port = sdp_get_address(dst, sizeof(dst), &ttl, ac[0]->filename);
650  is_multicast = resolve_destination(dst, sizeof(dst), dst_type,
651  sizeof(dst_type));
652  if (!is_multicast)
653  ttl = 0;
654  if (dst[0]) {
655  s.dst_addr = dst;
656  s.dst_type = dst_type;
657  s.ttl = ttl;
658  if (!strcmp(dst_type, "IP6")) {
659  s.src_addr = "::1";
660  s.src_type = "IP6";
661  }
662  }
663  }
664  sdp_write_header(buf, size, &s);
665 
666  dst[0] = 0;
667  for (i = 0; i < n_files; i++) {
668  if (n_files != 1) {
669  port = sdp_get_address(dst, sizeof(dst), &ttl, ac[i]->filename);
670  is_multicast = resolve_destination(dst, sizeof(dst), dst_type,
671  sizeof(dst_type));
672  if (!is_multicast)
673  ttl = 0;
674  }
675  for (j = 0; j < ac[i]->nb_streams; j++) {
676  ff_sdp_write_media(buf, size, ac[i]->streams[j], index++,
677  dst[0] ? dst : NULL, dst_type,
678  (port > 0) ? port + j * 2 : 0,
679  ttl, ac[i]);
680  if (port <= 0) {
681  av_strlcatf(buf, size,
682  "a=control:streamid=%d\r\n", i + j);
683  }
684  if (ac[i]->pb && ac[i]->pb->av_class) {
685  uint8_t *crypto_suite = NULL, *crypto_params = NULL;
686  av_opt_get(ac[i]->pb, "srtp_out_suite", AV_OPT_SEARCH_CHILDREN,
687  &crypto_suite);
688  av_opt_get(ac[i]->pb, "srtp_out_params", AV_OPT_SEARCH_CHILDREN,
689  &crypto_params);
690  if (crypto_suite && crypto_suite[0])
691  av_strlcatf(buf, size,
692  "a=crypto:1 %s inline:%s\r\n",
693  crypto_suite, crypto_params);
694  av_free(crypto_suite);
695  av_free(crypto_params);
696  }
697  }
698  }
699 
700  return 0;
701 }
702 #else
703 int av_sdp_create(AVFormatContext *ac[], int n_files, char *buf, int size)
704 {
705  return AVERROR(ENOSYS);
706 }
707 
708 void ff_sdp_write_media(char *buff, int size, AVStream *st, int idx,
709  const char *dest_addr, const char *dest_type,
710  int port, int ttl, AVFormatContext *fmt)
711 {
712 }
713 #endif
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