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webmdashenc.c
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1 /*
2  * WebM DASH Manifest XML muxer
3  * Copyright (c) 2014 Vignesh Venkatasubramanian
4  *
5  * This file is part of FFmpeg.
6  *
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.
11  *
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.
16  *
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
20  */
21 
22 /*
23  * WebM DASH Specification:
24  * https://sites.google.com/a/webmproject.org/wiki/adaptive-streaming/webm-dash-specification
25  */
26 
27 #include <stdint.h>
28 #include <string.h>
29 
30 #include "avformat.h"
31 #include "avio_internal.h"
32 #include "matroska.h"
33 
34 #include "libavutil/avstring.h"
35 #include "libavutil/dict.h"
36 #include "libavutil/opt.h"
37 
38 typedef struct AdaptationSet {
39  char id[10];
40  int *streams;
41  int nb_streams;
42 } AdaptationSet;
43 
44 typedef struct WebMDashMuxContext {
45  const AVClass *class;
46  char *adaptation_sets;
47  AdaptationSet *as;
48  int nb_as;
49  int representation_id;
50 } WebMDashMuxContext;
51 
52 static const char *get_codec_name(int codec_id)
53 {
54  switch (codec_id) {
55  case AV_CODEC_ID_VP8:
56  return "vp8";
57  case AV_CODEC_ID_VP9:
58  return "vp9";
59  case AV_CODEC_ID_VORBIS:
60  return "vorbis";
61  case AV_CODEC_ID_OPUS:
62  return "opus";
63  }
64  return NULL;
65 }
66 
67 static double get_duration(AVFormatContext *s)
68 {
69  int i = 0;
70  double max = 0.0;
71  for (i = 0; i < s->nb_streams; i++) {
72  AVDictionaryEntry *duration = av_dict_get(s->streams[i]->metadata,
73  DURATION, NULL, 0);
74  if (!duration || atof(duration->value) < 0) continue;
75  if (atof(duration->value) > max) max = atof(duration->value);
76  }
77  return max / 1000;
78 }
79 
80 static void write_header(AVFormatContext *s)
81 {
82  double min_buffer_time = 1.0;
83  avio_printf(s->pb, "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n");
84  avio_printf(s->pb, "<MPD\n");
85  avio_printf(s->pb, " xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"\n");
86  avio_printf(s->pb, " xmlns=\"urn:mpeg:DASH:schema:MPD:2011\"\n");
87  avio_printf(s->pb, " xsi:schemaLocation=\"urn:mpeg:DASH:schema:MPD:2011\"\n");
88  avio_printf(s->pb, " type=\"static\"\n");
89  avio_printf(s->pb, " mediaPresentationDuration=\"PT%gS\"\n",
90  get_duration(s));
91  avio_printf(s->pb, " minBufferTime=\"PT%gS\"\n",
92  min_buffer_time);
93  avio_printf(s->pb, " profiles=\"urn:webm:dash:profile:webm-on-demand:2012\"");
94  avio_printf(s->pb, ">\n");
95 }
96 
97 static void write_footer(AVFormatContext *s)
98 {
99  avio_printf(s->pb, "</MPD>\n");
100 }
101 
102 static int subsegment_alignment(AVFormatContext *s, AdaptationSet *as) {
103  int i;
104  AVDictionaryEntry *gold = av_dict_get(s->streams[as->streams[0]]->metadata,
105  CUE_TIMESTAMPS, NULL, 0);
106  if (!gold) return 0;
107  for (i = 1; i < as->nb_streams; i++) {
108  AVDictionaryEntry *ts = av_dict_get(s->streams[as->streams[i]]->metadata,
109  CUE_TIMESTAMPS, NULL, 0);
110  if (!ts || strncmp(gold->value, ts->value, strlen(gold->value))) return 0;
111  }
112  return 1;
113 }
114 
115 static int bitstream_switching(AVFormatContext *s, AdaptationSet *as) {
116  int i;
117  AVDictionaryEntry *gold_track_num = av_dict_get(s->streams[as->streams[0]]->metadata,
118  TRACK_NUMBER, NULL, 0);
119  AVCodecContext *gold_codec = s->streams[as->streams[0]]->codec;
120  if (!gold_track_num) return 0;
121  for (i = 1; i < as->nb_streams; i++) {
122  AVDictionaryEntry *track_num = av_dict_get(s->streams[as->streams[i]]->metadata,
123  TRACK_NUMBER, NULL, 0);
124  AVCodecContext *codec = s->streams[as->streams[i]]->codec;
125  if (!track_num ||
126  strncmp(gold_track_num->value, track_num->value, strlen(gold_track_num->value)) ||
127  gold_codec->codec_id != codec->codec_id ||
128  gold_codec->extradata_size != codec->extradata_size ||
129  memcmp(gold_codec->extradata, codec->extradata, codec->extradata_size)) {
130  return 0;
131  }
132  }
133  return 1;
134 }
135 
136 /*
137  * Writes a Representation within an Adaptation Set. Returns 0 on success and
138  * < 0 on failure.
139  */
140 static int write_representation(AVFormatContext *s, AVStream *stream, int id,
141  int output_width, int output_height,
142  int output_sample_rate) {
143  AVDictionaryEntry *irange = av_dict_get(stream->metadata, INITIALIZATION_RANGE, NULL, 0);
144  AVDictionaryEntry *cues_start = av_dict_get(stream->metadata, CUES_START, NULL, 0);
145  AVDictionaryEntry *cues_end = av_dict_get(stream->metadata, CUES_END, NULL, 0);
146  AVDictionaryEntry *filename = av_dict_get(stream->metadata, FILENAME, NULL, 0);
147  AVDictionaryEntry *bandwidth = av_dict_get(stream->metadata, BANDWIDTH, NULL, 0);
148  if (!irange || cues_start == NULL || cues_end == NULL || filename == NULL ||
149  !bandwidth) {
150  return -1;
151  }
152  avio_printf(s->pb, "<Representation id=\"%d\"", id);
153  avio_printf(s->pb, " bandwidth=\"%s\"", bandwidth->value);
154  if (stream->codec->codec_type == AVMEDIA_TYPE_VIDEO && output_width)
155  avio_printf(s->pb, " width=\"%d\"", stream->codec->width);
156  if (stream->codec->codec_type == AVMEDIA_TYPE_VIDEO && output_height)
157  avio_printf(s->pb, " height=\"%d\"", stream->codec->height);
158  if (stream->codec->codec_type = AVMEDIA_TYPE_AUDIO && output_sample_rate)
159  avio_printf(s->pb, " audioSamplingRate=\"%d\"", stream->codec->sample_rate);
160  avio_printf(s->pb, ">\n");
161  avio_printf(s->pb, "<BaseURL>%s</BaseURL>\n", filename->value);
162  avio_printf(s->pb, "<SegmentBase\n");
163  avio_printf(s->pb, " indexRange=\"%s-%s\">\n", cues_start->value, cues_end->value);
164  avio_printf(s->pb, "<Initialization\n");
165  avio_printf(s->pb, " range=\"0-%s\" />\n", irange->value);
166  avio_printf(s->pb, "</SegmentBase>\n");
167  avio_printf(s->pb, "</Representation>\n");
168  return 0;
169 }
170 
171 /*
172  * Checks if width of all streams are the same. Returns 1 if true, 0 otherwise.
173  */
174 static int check_matching_width(AVFormatContext *s, AdaptationSet *as) {
175  int first_width, i;
176  if (as->nb_streams < 2) return 1;
177  first_width = s->streams[as->streams[0]]->codec->width;
178  for (i = 1; i < as->nb_streams; i++)
179  if (first_width != s->streams[as->streams[i]]->codec->width)
180  return 0;
181  return 1;
182 }
183 
184 /*
185  * Checks if height of all streams are the same. Returns 1 if true, 0 otherwise.
186  */
187 static int check_matching_height(AVFormatContext *s, AdaptationSet *as) {
188  int first_height, i;
189  if (as->nb_streams < 2) return 1;
190  first_height = s->streams[as->streams[0]]->codec->height;
191  for (i = 1; i < as->nb_streams; i++)
192  if (first_height != s->streams[as->streams[i]]->codec->height)
193  return 0;
194  return 1;
195 }
196 
197 /*
198  * Checks if sample rate of all streams are the same. Returns 1 if true, 0 otherwise.
199  */
200 static int check_matching_sample_rate(AVFormatContext *s, AdaptationSet *as) {
201  int first_sample_rate, i;
202  if (as->nb_streams < 2) return 1;
203  first_sample_rate = s->streams[as->streams[0]]->codec->sample_rate;
204  for (i = 1; i < as->nb_streams; i++)
205  if (first_sample_rate != s->streams[as->streams[i]]->codec->sample_rate)
206  return 0;
207  return 1;
208 }
209 
210 /*
211  * Writes an Adaptation Set. Returns 0 on success and < 0 on failure.
212  */
213 static int write_adaptation_set(AVFormatContext *s, int as_index)
214 {
215  WebMDashMuxContext *w = s->priv_data;
216  AdaptationSet *as = &w->as[as_index];
217  AVCodecContext *codec = s->streams[as->streams[0]]->codec;
218  AVDictionaryEntry *lang;
219  int i;
220  static const char boolean[2][6] = { "false", "true" };
221  int subsegmentStartsWithSAP = 1;
222 
223  // Width, Height and Sample Rate will go in the AdaptationSet tag if they
224  // are the same for all contained Representations. otherwise, they will go
225  // on their respective Representation tag.
226  int width_in_as = 1, height_in_as = 1, sample_rate_in_as = 1;
227  if (codec->codec_type == AVMEDIA_TYPE_VIDEO) {
228  width_in_as = check_matching_width(s, as);
229  height_in_as = check_matching_height(s, as);
230  } else {
231  sample_rate_in_as = check_matching_sample_rate(s, as);
232  }
233 
234  avio_printf(s->pb, "<AdaptationSet id=\"%s\"", as->id);
235  avio_printf(s->pb, " mimeType=\"%s/webm\"",
236  codec->codec_type == AVMEDIA_TYPE_VIDEO ? "video" : "audio");
237  avio_printf(s->pb, " codecs=\"%s\"", get_codec_name(codec->codec_id));
238 
239  lang = av_dict_get(s->streams[as->streams[0]]->metadata, "language", NULL, 0);
240  if (lang) avio_printf(s->pb, " lang=\"%s\"", lang->value);
241 
242  if (codec->codec_type == AVMEDIA_TYPE_VIDEO && width_in_as)
243  avio_printf(s->pb, " width=\"%d\"", codec->width);
244  if (codec->codec_type == AVMEDIA_TYPE_VIDEO && height_in_as)
245  avio_printf(s->pb, " height=\"%d\"", codec->height);
246  if (codec->codec_type == AVMEDIA_TYPE_AUDIO && sample_rate_in_as)
247  avio_printf(s->pb, " audioSamplingRate=\"%d\"", codec->sample_rate);
248 
249  avio_printf(s->pb, " bitstreamSwitching=\"%s\"",
250  boolean[bitstream_switching(s, as)]);
251  avio_printf(s->pb, " subsegmentAlignment=\"%s\"",
252  boolean[subsegment_alignment(s, as)]);
253 
254  for (i = 0; i < as->nb_streams; i++) {
255  AVDictionaryEntry *kf = av_dict_get(s->streams[as->streams[i]]->metadata,
256  CLUSTER_KEYFRAME, NULL, 0);
257  if (!kf || !strncmp(kf->value, "0", 1)) subsegmentStartsWithSAP = 0;
258  }
259  avio_printf(s->pb, " subsegmentStartsWithSAP=\"%d\"", subsegmentStartsWithSAP);
260  avio_printf(s->pb, ">\n");
261 
262  for (i = 0; i < as->nb_streams; i++) {
263  write_representation(s, s->streams[as->streams[i]], w->representation_id++,
264  !width_in_as, !height_in_as, !sample_rate_in_as);
265  }
266  avio_printf(s->pb, "</AdaptationSet>\n");
267  return 0;
268 }
269 
270 static int to_integer(char *p, int len)
271 {
272  int ret;
273  char *q = av_malloc(sizeof(char) * len);
274  if (!q) return -1;
275  av_strlcpy(q, p, len);
276  ret = atoi(q);
277  av_free(q);
278  return ret;
279 }
280 
281 static int parse_adaptation_sets(AVFormatContext *s)
282 {
283  WebMDashMuxContext *w = s->priv_data;
284  char *p = w->adaptation_sets;
285  char *q;
286  enum { new_set, parsed_id, parsing_streams } state;
287  // syntax id=0,streams=0,1,2 id=1,streams=3,4 and so on
288  state = new_set;
289  while (p < w->adaptation_sets + strlen(w->adaptation_sets)) {
290  if (*p == ' ')
291  continue;
292  else if (state == new_set && !strncmp(p, "id=", 3)) {
293  w->as = av_realloc(w->as, sizeof(*w->as) * ++w->nb_as);
294  if (w->as == NULL) return -1;
295  w->as[w->nb_as - 1].nb_streams = 0;
296  w->as[w->nb_as - 1].streams = NULL;
297  p += 3; // consume "id="
298  q = w->as[w->nb_as - 1].id;
299  while (*p != ',') *q++ = *p++;
300  *q = 0;
301  p++;
302  state = parsed_id;
303  } else if (state == parsed_id && !strncmp(p, "streams=", 8)) {
304  p += 8; // consume "streams="
305  state = parsing_streams;
306  } else if (state == parsing_streams) {
307  struct AdaptationSet *as = &w->as[w->nb_as - 1];
308  q = p;
309  while (*q != '\0' && *q != ',' && *q != ' ') q++;
310  as->streams = av_realloc(as->streams, sizeof(*as->streams) * ++as->nb_streams);
311  if (as->streams == NULL) return -1;
312  as->streams[as->nb_streams - 1] = to_integer(p, q - p + 1);
313  if (as->streams[as->nb_streams - 1] < 0) return -1;
314  if (*q == '\0') break;
315  if (*q == ' ') state = new_set;
316  p = ++q;
317  } else {
318  return -1;
319  }
320  }
321  return 0;
322 }
323 
324 static int webm_dash_manifest_write_header(AVFormatContext *s)
325 {
326  int i;
327  double start = 0.0;
328  WebMDashMuxContext *w = s->priv_data;
329  parse_adaptation_sets(s);
330  write_header(s);
331  avio_printf(s->pb, "<Period id=\"0\"");
332  avio_printf(s->pb, " start=\"PT%gS\"", start);
333  avio_printf(s->pb, " duration=\"PT%gS\"", get_duration(s));
334  avio_printf(s->pb, " >\n");
335 
336  for (i = 0; i < w->nb_as; i++) {
337  if (write_adaptation_set(s, i) < 0) return -1;
338  }
339 
340  avio_printf(s->pb, "</Period>\n");
341  write_footer(s);
342  return 0;
343 }
344 
345 static int webm_dash_manifest_write_packet(AVFormatContext *s, AVPacket *pkt)
346 {
347  return AVERROR_EOF;
348 }
349 
350 static int webm_dash_manifest_write_trailer(AVFormatContext *s)
351 {
352  WebMDashMuxContext *w = s->priv_data;
353  int i;
354  for (i = 0; i < w->nb_as; i++) {
355  av_freep(&w->as[i].streams);
356  }
357  av_freep(&w->as);
358  return 0;
359 }
360 
361 #define OFFSET(x) offsetof(WebMDashMuxContext, x)
362 static const AVOption options[] = {
363  { "adaptation_sets", "Adaptation sets. Syntax: id=0,streams=0,1,2 id=1,streams=3,4 and so on", OFFSET(adaptation_sets), AV_OPT_TYPE_STRING, { 0 }, 0, 0, AV_OPT_FLAG_ENCODING_PARAM },
364  { NULL },
365 };
366 
367 #if CONFIG_WEBM_DASH_MANIFEST_MUXER
368 static const AVClass webm_dash_class = {
369  .class_name = "WebM DASH Manifest muxer",
370  .item_name = av_default_item_name,
371  .option = options,
372  .version = LIBAVUTIL_VERSION_INT,
373 };
374 
375 AVOutputFormat ff_webm_dash_manifest_muxer = {
376  .name = "webm_dash_manifest",
377  .long_name = NULL_IF_CONFIG_SMALL("WebM DASH Manifest"),
378  .mime_type = "application/xml",
379  .extensions = "xml",
380  .priv_data_size = sizeof(WebMDashMuxContext),
381  .write_header = webm_dash_manifest_write_header,
382  .write_packet = webm_dash_manifest_write_packet,
383  .write_trailer = webm_dash_manifest_write_trailer,
384  .priv_class = &webm_dash_class,
385 };
386 #endif
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