FFmpeg: libavformat/hlsproto.c Source File

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libavformat

hlsproto.c

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1 /*

2 * Apple HTTP Live Streaming Protocol Handler

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 */

22 /**

23 * @file

24 * Apple HTTP Live Streaming Protocol Handler

25 * http://tools.ietf.org/html/draft-pantos-http-live-streaming

26 */

28 #include "libavutil/avstring.h"

29 #include "libavutil/time.h"

30 #include "avformat.h"

31 #include "internal.h"

32 #include "url.h"

33 #include "version.h"

35 /*

36 * An apple http stream consists of a playlist with media segment files,

37 * played sequentially. There may be several playlists with the same

38 * video content, in different bandwidth variants, that are played in

39 * parallel (preferably only one bandwidth variant at a time). In this case,

40 * the user supplied the url to a main playlist that only lists the variant

41 * playlists.

42 *

43 * If the main playlist doesn't point at any variants, we still create

44 * one anonymous toplevel variant for this, to maintain the structure.

45 */

47 struct segment {

48 int duration;

49 char url[MAX_URL_SIZE];

50 };

52 struct variant {

53 int bandwidth;

54 char url[MAX_URL_SIZE];

55 };

57 typedef struct HLSContext {

58 char playlisturl[MAX_URL_SIZE];

59 int target_duration;

60 int start_seq_no;

61 int finished;

62 int n_segments;

63 struct segment **segments;

64 int n_variants;

65 struct variant **variants;

66 int cur_seq_no;

67 URLContext *seg_hd;

68 int64_t last_load_time;

69 } HLSContext;

71 static int read_chomp_line(AVIOContext *s, char *buf, int maxlen)

72 {

73 int len = ff_get_line(s, buf, maxlen);

74 while (len > 0 && av_isspace(buf[len - 1]))

75 buf[--len] = '0円';

76 return len;

77 }

79 static void free_segment_list(HLSContext *s)

80 {

81 int i;

82 for (i = 0; i < s->n_segments; i++)

83 av_free(s->segments[i]);

84 av_freep(&s->segments);

85 s->n_segments = 0;

86 }

88 static void free_variant_list(HLSContext *s)

89 {

90 int i;

91 for (i = 0; i < s->n_variants; i++)

92 av_free(s->variants[i]);

93 av_freep(&s->variants);

94 s->n_variants = 0;

95 }

97 struct variant_info {

98 char bandwidth[20];

99 };

100

101 static void handle_variant_args(struct variant_info *info, const char *key,

102 int key_len, char **dest, int *dest_len)

103 {

104 if (!strncmp(key, "BANDWIDTH=", key_len)) {

105 *dest = info->bandwidth;

106 *dest_len = sizeof(info->bandwidth);

107 }

108 }

109

110 static int parse_playlist(URLContext *h, const char *url)

111 {

112 HLSContext *s = h->priv_data;

113 AVIOContext *in;

114 int ret = 0, duration = 0, is_segment = 0, is_variant = 0, bandwidth = 0;

115 char line[1024];

116 const char *ptr;

117

118 if ((ret = avio_open2(&in, url, AVIO_FLAG_READ,

119 &h->interrupt_callback, NULL)) < 0)

120 return ret;

121

122 read_chomp_line(in, line, sizeof(line));

123 if (strcmp(line, "#EXTM3U"))

124 return AVERROR_INVALIDDATA;

125

126 free_segment_list(s);

127 s->finished = 0;

128 while (!url_feof(in)) {

129 read_chomp_line(in, line, sizeof(line));

130 if (av_strstart(line, "#EXT-X-STREAM-INF:", &ptr)) {

131 struct variant_info info = {{0}};

132 is_variant = 1;

133 ff_parse_key_value(ptr, (ff_parse_key_val_cb) handle_variant_args,

134 &info);

135 bandwidth = atoi(info.bandwidth);

136 } else if (av_strstart(line, "#EXT-X-TARGETDURATION:", &ptr)) {

137 s->target_duration = atoi(ptr);

138 } else if (av_strstart(line, "#EXT-X-MEDIA-SEQUENCE:", &ptr)) {

139 s->start_seq_no = atoi(ptr);

140 } else if (av_strstart(line, "#EXT-X-ENDLIST", &ptr)) {

141 s->finished = 1;

142 } else if (av_strstart(line, "#EXTINF:", &ptr)) {

143 is_segment = 1;

144 duration = atoi(ptr);

145 } else if (av_strstart(line, "#", NULL)) {

146 continue;

147 } else if (line[0]) {

148 if (is_segment) {

149 struct segment *seg = av_malloc(sizeof(struct segment));

150 if (!seg) {

151 ret = AVERROR(ENOMEM);

152 goto fail;

153 }

154 seg->duration = duration;

155 ff_make_absolute_url(seg->url, sizeof(seg->url), url, line);

156 dynarray_add(&s->segments, &s->n_segments, seg);

157 is_segment = 0;

158 } else if (is_variant) {

159 struct variant *var = av_malloc(sizeof(struct variant));

160 if (!var) {

161 ret = AVERROR(ENOMEM);

162 goto fail;

163 }

164 var->bandwidth = bandwidth;

165 ff_make_absolute_url(var->url, sizeof(var->url), url, line);

166 dynarray_add(&s->variants, &s->n_variants, var);

167 is_variant = 0;

168 }

169 }

170 }

171 s->last_load_time = av_gettime();

172

173 fail:

174 avio_close(in);

175 return ret;

176 }

177

178 static int hls_close(URLContext *h)

179 {

180 HLSContext *s = h->priv_data;

181

182 free_segment_list(s);

183 free_variant_list(s);

184 ffurl_close(s->seg_hd);

185 return 0;

186 }

187

188 static int hls_open(URLContext *h, const char *uri, int flags)

189 {

190 HLSContext *s = h->priv_data;

191 int ret, i;

192 const char *nested_url;

193

194 if (flags & AVIO_FLAG_WRITE)

195 return AVERROR(ENOSYS);

196

197 h->is_streamed = 1;

198

199 if (av_strstart(uri, "hls+", &nested_url)) {

200 av_strlcpy(s->playlisturl, nested_url, sizeof(s->playlisturl));

201 } else if (av_strstart(uri, "hls://", &nested_url)) {

202 av_log(h, AV_LOG_ERROR,

203 "No nested protocol specified. Specify e.g. hls+http://%s\n",

204 nested_url);

205 ret = AVERROR(EINVAL);

206 goto fail;

207 } else {

208 av_log(h, AV_LOG_ERROR, "Unsupported url %s\n", uri);

209 ret = AVERROR(EINVAL);

210 goto fail;

211 }

212 av_log(h, AV_LOG_WARNING,

213 "Using the hls protocol is discouraged, please try using the "

214 "hls demuxer instead. The hls demuxer should be more complete "

215 "and work as well as the protocol implementation. (If not, "

216 "please report it.) To use the demuxer, simply use %s as url.\n",

217 s->playlisturl);

218

219 if ((ret = parse_playlist(h, s->playlisturl)) < 0)

220 goto fail;

221

222 if (s->n_segments == 0 && s->n_variants > 0) {

223 int max_bandwidth = 0, maxvar = -1;

224 for (i = 0; i < s->n_variants; i++) {

225 if (s->variants[i]->bandwidth > max_bandwidth || i == 0) {

226 max_bandwidth = s->variants[i]->bandwidth;

227 maxvar = i;

228 }

229 }

230 av_strlcpy(s->playlisturl, s->variants[maxvar]->url,

231 sizeof(s->playlisturl));

232 if ((ret = parse_playlist(h, s->playlisturl)) < 0)

233 goto fail;

234 }

235

236 if (s->n_segments == 0) {

237 av_log(h, AV_LOG_WARNING, "Empty playlist\n");

238 ret = AVERROR(EIO);

239 goto fail;

240 }

241 s->cur_seq_no = s->start_seq_no;

242 if (!s->finished && s->n_segments >= 3)

243 s->cur_seq_no = s->start_seq_no + s->n_segments - 3;

244

245 return 0;

246

247 fail:

248 hls_close(h);

249 return ret;

250 }

251

252 static int hls_read(URLContext *h, uint8_t *buf, int size)

253 {

254 HLSContext *s = h->priv_data;

255 const char *url;

256 int ret;

257 int64_t reload_interval;

258

259 start:

260 if (s->seg_hd) {

261 ret = ffurl_read(s->seg_hd, buf, size);

262 if (ret > 0)

263 return ret;

264 }

265 if (s->seg_hd) {

266 ffurl_close(s->seg_hd);

267 s->seg_hd = NULL;

268 s->cur_seq_no++;

269 }

270 reload_interval = s->n_segments > 0 ?

271 s->segments[s->n_segments - 1]->duration :

272 s->target_duration;

273 reload_interval *= 1000000;

274 retry:

275 if (!s->finished) {

276 int64_t now = av_gettime();

277 if (now - s->last_load_time >= reload_interval) {

278 if ((ret = parse_playlist(h, s->playlisturl)) < 0)

279 return ret;

280 /* If we need to reload the playlist again below (if

281 * there's still no more segments), switch to a reload

282 * interval of half the target duration. */

283 reload_interval = s->target_duration * 500000LL;

284 }

285 }

286 if (s->cur_seq_no < s->start_seq_no) {

287 av_log(h, AV_LOG_WARNING,

288 "skipping %d segments ahead, expired from playlist\n",

289 s->start_seq_no - s->cur_seq_no);

290 s->cur_seq_no = s->start_seq_no;

291 }

292 if (s->cur_seq_no - s->start_seq_no >= s->n_segments) {

293 if (s->finished)

294 return AVERROR_EOF;

295 while (av_gettime() - s->last_load_time < reload_interval) {

296 if (ff_check_interrupt(&h->interrupt_callback))

297 return AVERROR_EXIT;

298 av_usleep(100*1000);

299 }

300 goto retry;

301 }

302 url = s->segments[s->cur_seq_no - s->start_seq_no]->url,

303 av_log(h, AV_LOG_DEBUG, "opening %s\n", url);

304 ret = ffurl_open(&s->seg_hd, url, AVIO_FLAG_READ,

305 &h->interrupt_callback, NULL);

306 if (ret < 0) {

307 if (ff_check_interrupt(&h->interrupt_callback))

308 return AVERROR_EXIT;

309 av_log(h, AV_LOG_WARNING, "Unable to open %s\n", url);

310 s->cur_seq_no++;

311 goto retry;

312 }

313 goto start;

314 }

315

316 URLProtocol ff_hls_protocol = {

317 .name = "hls",

318 .url_open = hls_open,

319 .url_read = hls_read,

320 .url_close = hls_close,

321 .flags = URL_PROTOCOL_FLAG_NESTED_SCHEME,

322 .priv_data_size = sizeof(HLSContext),

323 };

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