FFmpeg: libavformat/aiffdec.c Source File

FFmpeg

[フレーム]

libavformat

aiffdec.c

Go to the documentation of this file.

1 /*

2 * AIFF/AIFF-C demuxer

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/intreadwrite.h"

23 #include "libavutil/mathematics.h"

24 #include "libavutil/dict.h"

25 #include "avformat.h"

26 #include "internal.h"

27 #include "pcm.h"

28 #include "aiff.h"

29 #include "isom.h"

30 #include "id3v2.h"

31 #include "mov_chan.h"

33 #define AIFF 0

34 #define AIFF_C_VERSION1 0xA2805140

36 typedef struct {

37 int64_t data_end;

38 int block_duration;

39 } AIFFInputContext;

41 static enum AVCodecID aiff_codec_get_id(int bps)

42 {

43 if (bps <= 8)

44 return AV_CODEC_ID_PCM_S8;

45 if (bps <= 16)

46 return AV_CODEC_ID_PCM_S16BE;

47 if (bps <= 24)

48 return AV_CODEC_ID_PCM_S24BE;

49 if (bps <= 32)

50 return AV_CODEC_ID_PCM_S32BE;

52 /* bigger than 32 isn't allowed */

53 return AV_CODEC_ID_NONE;

54 }

56 /* returns the size of the found tag */

57 static int get_tag(AVIOContext *pb, uint32_t * tag)

58 {

59 int size;

61 if (url_feof(pb))

62 return AVERROR(EIO);

64 *tag = avio_rl32(pb);

65 size = avio_rb32(pb);

67 if (size < 0)

68 size = 0x7fffffff;

70 return size;

71 }

73 /* Metadata string read */

74 static void get_meta(AVFormatContext *s, const char *key, int size)

75 {

76 uint8_t *str = av_malloc(size+1);

78 if (str) {

79 int res = avio_read(s->pb, str, size);

80 if (res < 0){

81 av_free(str);

82 return;

83 }

84 size += (size&1)-res;

85 str[res] = 0;

86 av_dict_set(&s->metadata, key, str, AV_DICT_DONT_STRDUP_VAL);

87 }else

88 size+= size&1;

90 avio_skip(s->pb, size);

91 }

93 /* Returns the number of sound data frames or negative on error */

94 static unsigned int get_aiff_header(AVFormatContext *s, int size,

95 unsigned version)

96 {

97 AVIOContext *pb = s->pb;

98 AVCodecContext *codec = s->streams[0]->codec;

99 AIFFInputContext *aiff = s->priv_data;

100 int exp;

101 uint64_t val;

102 double sample_rate;

103 unsigned int num_frames;

104

105 if (size & 1)

106 size++;

107 codec->codec_type = AVMEDIA_TYPE_AUDIO;

108 codec->channels = avio_rb16(pb);

109 num_frames = avio_rb32(pb);

110 codec->bits_per_coded_sample = avio_rb16(pb);

111

112 exp = avio_rb16(pb);

113 val = avio_rb64(pb);

114 sample_rate = ldexp(val, exp - 16383 - 63);

115 codec->sample_rate = sample_rate;

116 size -= 18;

117

118 /* get codec id for AIFF-C */

119 if (version == AIFF_C_VERSION1) {

120 codec->codec_tag = avio_rl32(pb);

121 codec->codec_id = ff_codec_get_id(ff_codec_aiff_tags, codec->codec_tag);

122 size -= 4;

123 }

124

125 if (version != AIFF_C_VERSION1 || codec->codec_id == AV_CODEC_ID_PCM_S16BE) {

126 codec->codec_id = aiff_codec_get_id(codec->bits_per_coded_sample);

127 codec->bits_per_coded_sample = av_get_bits_per_sample(codec->codec_id);

128 aiff->block_duration = 1;

129 } else {

130 switch (codec->codec_id) {

131 case AV_CODEC_ID_PCM_F32BE:

132 case AV_CODEC_ID_PCM_F64BE:

133 case AV_CODEC_ID_PCM_S16LE:

134 case AV_CODEC_ID_PCM_ALAW:

135 case AV_CODEC_ID_PCM_MULAW:

136 aiff->block_duration = 1;

137 break;

138 case AV_CODEC_ID_ADPCM_IMA_QT:

139 codec->block_align = 34*codec->channels;

140 break;

141 case AV_CODEC_ID_MACE3:

142 codec->block_align = 2*codec->channels;

143 break;

144 case AV_CODEC_ID_MACE6:

145 codec->block_align = 1*codec->channels;

146 break;

147 case AV_CODEC_ID_GSM:

148 codec->block_align = 33;

149 break;

150 case AV_CODEC_ID_QCELP:

151 codec->block_align = 35;

152 break;

153 default:

154 aiff->block_duration = 1;

155 break;

156 }

157 if (codec->block_align > 0)

158 aiff->block_duration = av_get_audio_frame_duration(codec,

159 codec->block_align);

160 }

161

162 /* Block align needs to be computed in all cases, as the definition

163 * is specific to applications -> here we use the WAVE format definition */

164 if (!codec->block_align)

165 codec->block_align = (av_get_bits_per_sample(codec->codec_id) * codec->channels) >> 3;

166

167 if (aiff->block_duration) {

168 codec->bit_rate = codec->sample_rate * (codec->block_align << 3) /

169 aiff->block_duration;

170 }

171

172 /* Chunk is over */

173 if (size)

174 avio_skip(pb, size);

175

176 return num_frames;

177 }

178

179 static int aiff_probe(AVProbeData *p)

180 {

181 /* check file header */

182 if (p->buf[0] == 'F' && p->buf[1] == 'O' &&

183 p->buf[2] == 'R' && p->buf[3] == 'M' &&

184 p->buf[8] == 'A' && p->buf[9] == 'I' &&

185 p->buf[10] == 'F' && (p->buf[11] == 'F' || p->buf[11] == 'C'))

186 return AVPROBE_SCORE_MAX;

187 else

188 return 0;

189 }

190

191 /* aiff input */

192 static int aiff_read_header(AVFormatContext *s)

193 {

194 int ret, size, filesize;

195 int64_t offset = 0, position;

196 uint32_t tag;

197 unsigned version = AIFF_C_VERSION1;

198 AVIOContext *pb = s->pb;

199 AVStream * st;

200 AIFFInputContext *aiff = s->priv_data;

201 ID3v2ExtraMeta *id3v2_extra_meta = NULL;

202

203 /* check FORM header */

204 filesize = get_tag(pb, &tag);

205 if (filesize < 0 || tag != MKTAG('F', 'O', 'R', 'M'))

206 return AVERROR_INVALIDDATA;

207

208 /* AIFF data type */

209 tag = avio_rl32(pb);

210 if (tag == MKTAG('A', 'I', 'F', 'F')) /* Got an AIFF file */

211 version = AIFF;

212 else if (tag != MKTAG('A', 'I', 'F', 'C')) /* An AIFF-C file then */

213 return AVERROR_INVALIDDATA;

214

215 filesize -= 4;

216

217 st = avformat_new_stream(s, NULL);

218 if (!st)

219 return AVERROR(ENOMEM);

220

221 while (filesize > 0) {

222 /* parse different chunks */

223 size = get_tag(pb, &tag);

224 if (size < 0)

225 return size;

226

227 filesize -= size + 8;

228

229 switch (tag) {

230 case MKTAG('C', 'O', 'M', 'M'): /* Common chunk */

231 /* Then for the complete header info */

232 st->nb_frames = get_aiff_header(s, size, version);

233 if (st->nb_frames < 0)

234 return st->nb_frames;

235 if (offset > 0) // COMM is after SSND

236 goto got_sound;

237 break;

238 case MKTAG('I', 'D', '3', ' '):

239 position = avio_tell(pb);

240 ff_id3v2_read(s, ID3v2_DEFAULT_MAGIC, &id3v2_extra_meta);

241 if (id3v2_extra_meta)

242 if ((ret = ff_id3v2_parse_apic(s, &id3v2_extra_meta)) < 0) {

243 ff_id3v2_free_extra_meta(&id3v2_extra_meta);

244 return ret;

245 }

246 ff_id3v2_free_extra_meta(&id3v2_extra_meta);

247 if (position + size > avio_tell(pb))

248 avio_skip(pb, position + size - avio_tell(pb));

249 break;

250 case MKTAG('F', 'V', 'E', 'R'): /* Version chunk */

251 version = avio_rb32(pb);

252 break;

253 case MKTAG('N', 'A', 'M', 'E'): /* Sample name chunk */

254 get_meta(s, "title" , size);

255 break;

256 case MKTAG('A', 'U', 'T', 'H'): /* Author chunk */

257 get_meta(s, "author" , size);

258 break;

259 case MKTAG('(', 'c', ')', ' '): /* Copyright chunk */

260 get_meta(s, "copyright", size);

261 break;

262 case MKTAG('A', 'N', 'N', 'O'): /* Annotation chunk */

263 get_meta(s, "comment" , size);

264 break;

265 case MKTAG('S', 'S', 'N', 'D'): /* Sampled sound chunk */

266 aiff->data_end = avio_tell(pb) + size;

267 offset = avio_rb32(pb); /* Offset of sound data */

268 avio_rb32(pb); /* BlockSize... don't care */

269 offset += avio_tell(pb); /* Compute absolute data offset */

270 if (st->codec->block_align && !pb->seekable) /* Assume COMM already parsed */

271 goto got_sound;

272 if (!pb->seekable) {

273 av_log(s, AV_LOG_ERROR, "file is not seekable\n");

274 return -1;

275 }

276 avio_skip(pb, size - 8);

277 break;

278 case MKTAG('w', 'a', 'v', 'e'):

279 if ((uint64_t)size > (1<<30))

280 return -1;

281 st->codec->extradata = av_mallocz(size + FF_INPUT_BUFFER_PADDING_SIZE);

282 if (!st->codec->extradata)

283 return AVERROR(ENOMEM);

284 st->codec->extradata_size = size;

285 avio_read(pb, st->codec->extradata, size);

286 if (st->codec->codec_id == AV_CODEC_ID_QDM2 && size>=12*4 && !st->codec->block_align) {

287 st->codec->block_align = AV_RB32(st->codec->extradata+11*4);

288 aiff->block_duration = AV_RB32(st->codec->extradata+9*4);

289 }

290 break;

291 case MKTAG('C','H','A','N'):

292 if(ff_mov_read_chan(s, pb, st, size) < 0)

293 return AVERROR_INVALIDDATA;

294 break;

295 default: /* Jump */

296 if (size & 1) /* Always even aligned */

297 size++;

298 avio_skip(pb, size);

299 }

300 }

301

302 got_sound:

303 if (!st->codec->block_align) {

304 av_log(s, AV_LOG_ERROR, "could not find COMM tag or invalid block_align value\n");

305 return -1;

306 }

307

308 /* Now positioned, get the sound data start and end */

309 avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);

310 st->start_time = 0;

311 st->duration = st->nb_frames * aiff->block_duration;

312

313 /* Position the stream at the first block */

314 avio_seek(pb, offset, SEEK_SET);

315

316 return 0;

317 }

318

319 #define MAX_SIZE 4096

320

321 static int aiff_read_packet(AVFormatContext *s,

322 AVPacket *pkt)

323 {

324 AVStream *st = s->streams[0];

325 AIFFInputContext *aiff = s->priv_data;

326 int64_t max_size;

327 int res, size;

328

329 /* calculate size of remaining data */

330 max_size = aiff->data_end - avio_tell(s->pb);

331 if (max_size <= 0)

332 return AVERROR_EOF;

333

334 /* Now for that packet */

335 if (st->codec->block_align >= 33) // GSM, QCLP, IMA4

336 size = st->codec->block_align;

337 else

338 size = (MAX_SIZE / st->codec->block_align) * st->codec->block_align;

339 size = FFMIN(max_size, size);

340 res = av_get_packet(s->pb, pkt, size);

341 if (res < 0)

342 return res;

343

344 if (size >= st->codec->block_align)

345 pkt->flags &= ~AV_PKT_FLAG_CORRUPT;

346 /* Only one stream in an AIFF file */

347 pkt->stream_index = 0;

348 pkt->duration = (res / st->codec->block_align) * aiff->block_duration;

349 return 0;

350 }

351

352 AVInputFormat ff_aiff_demuxer = {

353 .name = "aiff",

354 .long_name = NULL_IF_CONFIG_SMALL("Audio IFF"),

355 .priv_data_size = sizeof(AIFFInputContext),

356 .read_probe = aiff_probe,

357 .read_header = aiff_read_header,

358 .read_packet = aiff_read_packet,

359 .read_seek = ff_pcm_read_seek,

360 .codec_tag = (const AVCodecTag* const []){ ff_codec_aiff_tags, 0 },

361 };

Generated on Sat May 25 2013 04:01:16 for FFmpeg by doxygen 1.8.2