FFmpeg: libavformat/format.c Source File

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libavformat

format.c

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1 /*

2 * Format register and lookup

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 #include "libavutil/atomic.h"

23 #include "libavutil/avstring.h"

24 #include "libavutil/bprint.h"

25 #include "libavutil/opt.h"

27 #include "avio_internal.h"

28 #include "avformat.h"

29 #include "id3v2.h"

30 #include "internal.h"

33 /**

34 * @file

35 * Format register and lookup

36 */

37 /** head of registered input format linked list */

38 static AVInputFormat *first_iformat = NULL;

39 /** head of registered output format linked list */

40 static AVOutputFormat *first_oformat = NULL;

42 static AVInputFormat **last_iformat = &first_iformat;

43 static AVOutputFormat **last_oformat = &first_oformat;

45 AVInputFormat *av_iformat_next(const AVInputFormat *f)

46 {

47 if (f)

48 return f->next;

49 else

50 return first_iformat;

51 }

53 AVOutputFormat *av_oformat_next(const AVOutputFormat *f)

54 {

55 if (f)

56 return f->next;

57 else

58 return first_oformat;

59 }

61 void av_register_input_format(AVInputFormat *format)

62 {

63 AVInputFormat **p = last_iformat;

65 format->next = NULL;

66 while(*p || avpriv_atomic_ptr_cas((void * volatile *)p, NULL, format))

67 p = &(*p)->next;

68 last_iformat = &format->next;

69 }

71 void av_register_output_format(AVOutputFormat *format)

72 {

73 AVOutputFormat **p = last_oformat;

75 format->next = NULL;

76 while(*p || avpriv_atomic_ptr_cas((void * volatile *)p, NULL, format))

77 p = &(*p)->next;

78 last_oformat = &format->next;

79 }

81 int av_match_ext(const char *filename, const char *extensions)

82 {

83 const char *ext;

85 if (!filename)

86 return 0;

88 ext = strrchr(filename, '.');

89 if (ext)

90 return av_match_name(ext + 1, extensions);

91 return 0;

92 }

94 AVOutputFormat *av_guess_format(const char *short_name, const char *filename,

95 const char *mime_type)

96 {

97 AVOutputFormat *fmt = NULL, *fmt_found;

98 int score_max, score;

100 /* specific test for image sequences */

101 #if CONFIG_IMAGE2_MUXER

102 if (!short_name && filename &&

103 av_filename_number_test(filename) &&

104 ff_guess_image2_codec(filename) != AV_CODEC_ID_NONE) {

105 return av_guess_format("image2", NULL, NULL);

106 }

107 #endif

108 /* Find the proper file type. */

109 fmt_found = NULL;

110 score_max = 0;

111 while ((fmt = av_oformat_next(fmt))) {

112 score = 0;

113 if (fmt->name && short_name && av_match_name(short_name, fmt->name))

114 score += 100;

115 if (fmt->mime_type && mime_type && !strcmp(fmt->mime_type, mime_type))

116 score += 10;

117 if (filename && fmt->extensions &&

118 av_match_ext(filename, fmt->extensions)) {

119 score += 5;

120 }

121 if (score > score_max) {

122 score_max = score;

123 fmt_found = fmt;

124 }

125 }

126 return fmt_found;

127 }

128

129 enum AVCodecID av_guess_codec(AVOutputFormat *fmt, const char *short_name,

130 const char *filename, const char *mime_type,

131 enum AVMediaType type)

132 {

133 if (av_match_name("segment", fmt->name) || av_match_name("ssegment", fmt->name)) {

134 AVOutputFormat *fmt2 = av_guess_format(NULL, filename, NULL);

135 if (fmt2)

136 fmt = fmt2;

137 }

138

139 if (type == AVMEDIA_TYPE_VIDEO) {

140 enum AVCodecID codec_id = AV_CODEC_ID_NONE;

141

142 #if CONFIG_IMAGE2_MUXER

143 if (!strcmp(fmt->name, "image2") || !strcmp(fmt->name, "image2pipe")) {

144 codec_id = ff_guess_image2_codec(filename);

145 }

146 #endif

147 if (codec_id == AV_CODEC_ID_NONE)

148 codec_id = fmt->video_codec;

149 return codec_id;

150 } else if (type == AVMEDIA_TYPE_AUDIO)

151 return fmt->audio_codec;

152 else if (type == AVMEDIA_TYPE_SUBTITLE)

153 return fmt->subtitle_codec;

154 else if (type == AVMEDIA_TYPE_DATA)

155 return fmt->data_codec;

156 else

157 return AV_CODEC_ID_NONE;

158 }

159

160 AVInputFormat *av_find_input_format(const char *short_name)

161 {

162 AVInputFormat *fmt = NULL;

163 while ((fmt = av_iformat_next(fmt)))

164 if (av_match_name(short_name, fmt->name))

165 return fmt;

166 return NULL;

167 }

168

169 AVInputFormat *av_probe_input_format3(AVProbeData *pd, int is_opened,

170 int *score_ret)

171 {

172 AVProbeData lpd = *pd;

173 AVInputFormat *fmt1 = NULL, *fmt;

174 int score, nodat = 0, score_max = 0;

175 const static uint8_t zerobuffer[AVPROBE_PADDING_SIZE];

176

177 if (!lpd.buf)

178 lpd.buf = zerobuffer;

179

180 if (lpd.buf_size > 10 && ff_id3v2_match(lpd.buf, ID3v2_DEFAULT_MAGIC)) {

181 int id3len = ff_id3v2_tag_len(lpd.buf);

182 if (lpd.buf_size > id3len + 16) {

183 lpd.buf += id3len;

184 lpd.buf_size -= id3len;

185 } else if (id3len >= PROBE_BUF_MAX) {

186 nodat = 2;

187 } else

188 nodat = 1;

189 }

190

191 fmt = NULL;

192 while ((fmt1 = av_iformat_next(fmt1))) {

193 if (!is_opened == !(fmt1->flags & AVFMT_NOFILE) && strcmp(fmt1->name, "image2"))

194 continue;

195 score = 0;

196 if (fmt1->read_probe) {

197 score = fmt1->read_probe(&lpd);

198 if (fmt1->extensions && av_match_ext(lpd.filename, fmt1->extensions)) {

199 if (nodat == 0) score = FFMAX(score, 1);

200 else if (nodat == 1) score = FFMAX(score, AVPROBE_SCORE_EXTENSION / 2 - 1);

201 else score = FFMAX(score, AVPROBE_SCORE_EXTENSION);

202 }

203 } else if (fmt1->extensions) {

204 if (av_match_ext(lpd.filename, fmt1->extensions))

205 score = AVPROBE_SCORE_EXTENSION;

206 }

207 if (av_match_name(lpd.mime_type, fmt1->mime_type))

208 score = FFMAX(score, AVPROBE_SCORE_MIME);

209 if (score > score_max) {

210 score_max = score;

211 fmt = fmt1;

212 } else if (score == score_max)

213 fmt = NULL;

214 }

215 if (nodat == 1)

216 score_max = FFMIN(AVPROBE_SCORE_EXTENSION / 2 - 1, score_max);

217 *score_ret = score_max;

218

219 return fmt;

220 }

221

222 AVInputFormat *av_probe_input_format2(AVProbeData *pd, int is_opened, int *score_max)

223 {

224 int score_ret;

225 AVInputFormat *fmt = av_probe_input_format3(pd, is_opened, &score_ret);

226 if (score_ret > *score_max) {

227 *score_max = score_ret;

228 return fmt;

229 } else

230 return NULL;

231 }

232

233 AVInputFormat *av_probe_input_format(AVProbeData *pd, int is_opened)

234 {

235 int score = 0;

236 return av_probe_input_format2(pd, is_opened, &score);

237 }

238

239 int av_probe_input_buffer2(AVIOContext *pb, AVInputFormat **fmt,

240 const char *filename, void *logctx,

241 unsigned int offset, unsigned int max_probe_size)

242 {

243 AVProbeData pd = { filename ? filename : "" };

244 uint8_t *buf = NULL;

245 int ret = 0, probe_size, buf_offset = 0;

246 int score = 0;

247 int ret2;

248

249 if (!max_probe_size)

250 max_probe_size = PROBE_BUF_MAX;

251 else if (max_probe_size < PROBE_BUF_MIN) {

252 av_log(logctx, AV_LOG_ERROR,

253 "Specified probe size value %u cannot be < %u\n", max_probe_size, PROBE_BUF_MIN);

254 return AVERROR(EINVAL);

255 }

256

257 if (offset >= max_probe_size)

258 return AVERROR(EINVAL);

259

260 if (pb->av_class) {

261 uint8_t *mime_type_opt = NULL;

262 av_opt_get(pb, "mime_type", AV_OPT_SEARCH_CHILDREN, &mime_type_opt);

263 pd.mime_type = (const char *)mime_type_opt;

264 }

265 #if 0

266 if (!*fmt && pb->av_class && av_opt_get(pb, "mime_type", AV_OPT_SEARCH_CHILDREN, &mime_type) >= 0 && mime_type) {

267 if (!av_strcasecmp(mime_type, "audio/aacp")) {

268 *fmt = av_find_input_format("aac");

269 }

270 av_freep(&mime_type);

271 }

272 #endif

273

274 for (probe_size = PROBE_BUF_MIN; probe_size <= max_probe_size && !*fmt;

275 probe_size = FFMIN(probe_size << 1,

276 FFMAX(max_probe_size, probe_size + 1))) {

277 score = probe_size < max_probe_size ? AVPROBE_SCORE_RETRY : 0;

278

279 /* Read probe data. */

280 if ((ret = av_reallocp(&buf, probe_size + AVPROBE_PADDING_SIZE)) < 0)

281 goto fail;

282 if ((ret = avio_read(pb, buf + buf_offset,

283 probe_size - buf_offset)) < 0) {

284 /* Fail if error was not end of file, otherwise, lower score. */

285 if (ret != AVERROR_EOF)

286 goto fail;

287

288 score = 0;

289 ret = 0; /* error was end of file, nothing read */

290 }

291 buf_offset += ret;

292 if (buf_offset < offset)

293 continue;

294 pd.buf_size = buf_offset - offset;

295 pd.buf = &buf[offset];

296

297 memset(pd.buf + pd.buf_size, 0, AVPROBE_PADDING_SIZE);

298

299 /* Guess file format. */

300 *fmt = av_probe_input_format2(&pd, 1, &score);

301 if (*fmt) {

302 /* This can only be true in the last iteration. */

303 if (score <= AVPROBE_SCORE_RETRY) {

304 av_log(logctx, AV_LOG_WARNING,

305 "Format %s detected only with low score of %d, "

306 "misdetection possible!\n", (*fmt)->name, score);

307 } else

308 av_log(logctx, AV_LOG_DEBUG,

309 "Format %s probed with size=%d and score=%d\n",

310 (*fmt)->name, probe_size, score);

311 #if 0

312 FILE *f = fopen("probestat.tmp", "ab");

313 fprintf(f, "probe_size:%d format:%s score:%d filename:%s\n", probe_size, (*fmt)->name, score, filename);

314 fclose(f);

315 #endif

316 }

317 }

318

319 if (!*fmt)

320 ret = AVERROR_INVALIDDATA;

321

322 fail:

323 /* Rewind. Reuse probe buffer to avoid seeking. */

324 ret2 = ffio_rewind_with_probe_data(pb, &buf, buf_offset);

325 if (ret >= 0)

326 ret = ret2;

327

328 av_freep(&pd.mime_type);

329 return ret < 0 ? ret : score;

330 }

331

332 int av_probe_input_buffer(AVIOContext *pb, AVInputFormat **fmt,

333 const char *filename, void *logctx,

334 unsigned int offset, unsigned int max_probe_size)

335 {

336 int ret = av_probe_input_buffer2(pb, fmt, filename, logctx, offset, max_probe_size);

337 return ret < 0 ? ret : 0;

338 }

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