FFmpeg: libavformat/cafdec.c Source File

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libavformat

cafdec.c

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1 /*

2 * Core Audio Format demuxer

5 *

6 * This file is part of FFmpeg.

7 *

8 * FFmpeg is free software; you can redistribute it and/or

9 * modify it under the terms of the GNU Lesser General Public

10 * License as published by the Free Software Foundation; either

11 * version 2.1 of the License, or (at your option) any later version.

12 *

13 * FFmpeg is distributed in the hope that it will be useful,

14 * but WITHOUT ANY WARRANTY; without even the implied warranty of

15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

16 * Lesser General Public License for more details.

17 *

18 * You should have received a copy of the GNU Lesser General Public

19 * License along with FFmpeg; if not, write to the Free Software

20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

21 */

23 /**

24 * @file

25 * Core Audio Format demuxer

26 */

28 #include "avformat.h"

29 #include "internal.h"

30 #include "isom.h"

31 #include "mov_chan.h"

32 #include "libavutil/intreadwrite.h"

33 #include "libavutil/intfloat.h"

34 #include "libavutil/dict.h"

35 #include "caf.h"

37 typedef struct {

38 int bytes_per_packet; ///< bytes in a packet, or 0 if variable

39 int frames_per_packet; ///< frames in a packet, or 0 if variable

40 int64_t num_bytes; ///< total number of bytes in stream

42 int64_t packet_cnt; ///< packet counter

43 int64_t frame_cnt; ///< frame counter

45 int64_t data_start; ///< data start position, in bytes

46 int64_t data_size; ///< raw data size, in bytes

47 } CaffContext;

49 static int probe(AVProbeData *p)

50 {

51 if (AV_RB32(p->buf) == MKBETAG('c','a','f','f') && AV_RB16(&p->buf[4]) == 1)

52 return AVPROBE_SCORE_MAX;

53 return 0;

54 }

56 /** Read audio description chunk */

57 static int read_desc_chunk(AVFormatContext *s)

58 {

59 AVIOContext *pb = s->pb;

60 CaffContext *caf = s->priv_data;

61 AVStream *st;

62 int flags;

64 /* new audio stream */

65 st = avformat_new_stream(s, NULL);

66 if (!st)

67 return AVERROR(ENOMEM);

69 /* parse format description */

70 st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

71 st->codec->sample_rate = av_int2double(avio_rb64(pb));

72 st->codec->codec_tag = avio_rl32(pb);

73 flags = avio_rb32(pb);

74 caf->bytes_per_packet = avio_rb32(pb);

75 st->codec->block_align = caf->bytes_per_packet;

76 caf->frames_per_packet = avio_rb32(pb);

77 st->codec->channels = avio_rb32(pb);

78 st->codec->bits_per_coded_sample = avio_rb32(pb);

80 /* calculate bit rate for constant size packets */

81 if (caf->frames_per_packet > 0 && caf->bytes_per_packet > 0) {

82 st->codec->bit_rate = (uint64_t)st->codec->sample_rate * (uint64_t)caf->bytes_per_packet * 8

83 / (uint64_t)caf->frames_per_packet;

84 } else {

85 st->codec->bit_rate = 0;

86 }

88 /* determine codec */

89 if (st->codec->codec_tag == MKTAG('l','p','c','m'))

90 st->codec->codec_id = ff_mov_get_lpcm_codec_id(st->codec->bits_per_coded_sample, (flags ^ 0x2) | 0x4);

91 else

92 st->codec->codec_id = ff_codec_get_id(ff_codec_caf_tags, st->codec->codec_tag);

93 return 0;

94 }

96 /** Read magic cookie chunk */

97 static int read_kuki_chunk(AVFormatContext *s, int64_t size)

98 {

99 AVIOContext *pb = s->pb;

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

101

102 if (size < 0 || size > INT_MAX - FF_INPUT_BUFFER_PADDING_SIZE)

103 return -1;

104

105 if (st->codec->codec_id == AV_CODEC_ID_AAC) {

106 /* The magic cookie format for AAC is an mp4 esds atom.

107 The lavc AAC decoder requires the data from the codec specific

108 description as extradata input. */

109 int strt, skip;

110 MOVAtom atom;

111

112 strt = avio_tell(pb);

113 ff_mov_read_esds(s, pb, atom);

114 skip = size - (avio_tell(pb) - strt);

115 if (skip < 0 || !st->codec->extradata ||

116 st->codec->codec_id != AV_CODEC_ID_AAC) {

117 av_log(s, AV_LOG_ERROR, "invalid AAC magic cookie\n");

118 return AVERROR_INVALIDDATA;

119 }

120 avio_skip(pb, skip);

121 } else if (st->codec->codec_id == AV_CODEC_ID_ALAC) {

122 #define ALAC_PREAMBLE 12

123 #define ALAC_HEADER 36

124 #define ALAC_NEW_KUKI 24

125 uint8_t preamble[12];

126 if (size < ALAC_NEW_KUKI) {

127 av_log(s, AV_LOG_ERROR, "invalid ALAC magic cookie\n");

128 avio_skip(pb, size);

129 return AVERROR_INVALIDDATA;

130 }

131 avio_read(pb, preamble, ALAC_PREAMBLE);

132

133 st->codec->extradata = av_mallocz(ALAC_HEADER + FF_INPUT_BUFFER_PADDING_SIZE);

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

135 return AVERROR(ENOMEM);

136

137 /* For the old style cookie, we skip 12 bytes, then read 36 bytes.

138 * The new style cookie only contains the last 24 bytes of what was

139 * 36 bytes in the old style cookie, so we fabricate the first 12 bytes

140 * in that case to maintain compatibility. */

141 if (!memcmp(&preamble[4], "frmaalac", 8)) {

142 if (size < ALAC_PREAMBLE + ALAC_HEADER) {

143 av_log(s, AV_LOG_ERROR, "invalid ALAC magic cookie\n");

144 av_freep(&st->codec->extradata);

145 return AVERROR_INVALIDDATA;

146 }

147 avio_read(pb, st->codec->extradata, ALAC_HEADER);

148 avio_skip(pb, size - ALAC_PREAMBLE - ALAC_HEADER);

149 } else {

150 AV_WB32(st->codec->extradata, 36);

151 memcpy(&st->codec->extradata[4], "alac", 4);

152 AV_WB32(&st->codec->extradata[8], 0);

153 memcpy(&st->codec->extradata[12], preamble, 12);

154 avio_read(pb, &st->codec->extradata[24], ALAC_NEW_KUKI - 12);

155 avio_skip(pb, size - ALAC_NEW_KUKI);

156 }

157 st->codec->extradata_size = ALAC_HEADER;

158 } else {

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

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

161 return AVERROR(ENOMEM);

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

163 st->codec->extradata_size = size;

164 }

165

166 return 0;

167 }

168

169 /** Read packet table chunk */

170 static int read_pakt_chunk(AVFormatContext *s, int64_t size)

171 {

172 AVIOContext *pb = s->pb;

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

174 CaffContext *caf = s->priv_data;

175 int64_t pos = 0, ccount, num_packets;

176 int i;

177

178 ccount = avio_tell(pb);

179

180 num_packets = avio_rb64(pb);

181 if (num_packets < 0 || INT32_MAX / sizeof(AVIndexEntry) < num_packets)

182 return AVERROR_INVALIDDATA;

183

184 st->nb_frames = avio_rb64(pb); /* valid frames */

185 st->nb_frames += avio_rb32(pb); /* priming frames */

186 st->nb_frames += avio_rb32(pb); /* remainder frames */

187

188 st->duration = 0;

189 for (i = 0; i < num_packets; i++) {

190 av_add_index_entry(s->streams[0], pos, st->duration, 0, 0, AVINDEX_KEYFRAME);

191 pos += caf->bytes_per_packet ? caf->bytes_per_packet : ff_mp4_read_descr_len(pb);

192 st->duration += caf->frames_per_packet ? caf->frames_per_packet : ff_mp4_read_descr_len(pb);

193 }

194

195 if (avio_tell(pb) - ccount > size) {

196 av_log(s, AV_LOG_ERROR, "error reading packet table\n");

197 return AVERROR_INVALIDDATA;

198 }

199 avio_skip(pb, ccount + size - avio_tell(pb));

200

201 caf->num_bytes = pos;

202 return 0;

203 }

204

205 /** Read information chunk */

206 static void read_info_chunk(AVFormatContext *s, int64_t size)

207 {

208 AVIOContext *pb = s->pb;

209 unsigned int i;

210 unsigned int nb_entries = avio_rb32(pb);

211 for (i = 0; i < nb_entries; i++) {

212 char key[32];

213 char value[1024];

214 avio_get_str(pb, INT_MAX, key, sizeof(key));

215 avio_get_str(pb, INT_MAX, value, sizeof(value));

216 av_dict_set(&s->metadata, key, value, 0);

217 }

218 }

219

220 static int read_header(AVFormatContext *s)

221 {

222 AVIOContext *pb = s->pb;

223 CaffContext *caf = s->priv_data;

224 AVStream *st;

225 uint32_t tag = 0;

226 int found_data, ret;

227 int64_t size, pos;

228

229 avio_skip(pb, 8); /* magic, version, file flags */

230

231 /* audio description chunk */

232 if (avio_rb32(pb) != MKBETAG('d','e','s','c')) {

233 av_log(s, AV_LOG_ERROR, "desc chunk not present\n");

234 return AVERROR_INVALIDDATA;

235 }

236 size = avio_rb64(pb);

237 if (size != 32)

238 return AVERROR_INVALIDDATA;

239

240 ret = read_desc_chunk(s);

241 if (ret)

242 return ret;

243 st = s->streams[0];

244

245 /* parse each chunk */

246 found_data = 0;

247 while (!url_feof(pb)) {

248

249 /* stop at data chunk if seeking is not supported or

250 data chunk size is unknown */

251 if (found_data && (caf->data_size < 0 || !pb->seekable))

252 break;

253

254 tag = avio_rb32(pb);

255 size = avio_rb64(pb);

256 pos = avio_tell(pb);

257 if (url_feof(pb))

258 break;

259

260 switch (tag) {

261 case MKBETAG('d','a','t','a'):

262 avio_skip(pb, 4); /* edit count */

263 caf->data_start = avio_tell(pb);

264 caf->data_size = size < 0 ? -1 : size - 4;

265 if (caf->data_size > 0 && pb->seekable)

266 avio_skip(pb, caf->data_size);

267 found_data = 1;

268 break;

269

270 case MKBETAG('c','h','a','n'):

271 if ((ret = ff_mov_read_chan(s, s->pb, st, size)) < 0)

272 return ret;

273 break;

274

275 /* magic cookie chunk */

276 case MKBETAG('k','u','k','i'):

277 if (read_kuki_chunk(s, size))

278 return AVERROR_INVALIDDATA;

279 break;

280

281 /* packet table chunk */

282 case MKBETAG('p','a','k','t'):

283 if (read_pakt_chunk(s, size))

284 return AVERROR_INVALIDDATA;

285 break;

286

287 case MKBETAG('i','n','f','o'):

288 read_info_chunk(s, size);

289 break;

290

291 default:

292 #define _(x) ((x) >= ' ' ? (x) : ' ')

293 av_log(s, AV_LOG_WARNING, "skipping CAF chunk: %08X (%c%c%c%c), size %"PRId64"\n",

294 tag, _(tag>>24), _((tag>>16)&0xFF), _((tag>>8)&0xFF), _(tag&0xFF), size);

295 #undef _

296 case MKBETAG('f','r','e','e'):

297 if (size < 0)

298 return AVERROR_INVALIDDATA;

299 break;

300 }

301

302 if (size > 0) {

303 if (pos > INT64_MAX - size)

304 return AVERROR_INVALIDDATA;

305 avio_skip(pb, FFMAX(0, pos + size - avio_tell(pb)));

306 }

307 }

308

309 if (!found_data)

310 return AVERROR_INVALIDDATA;

311

312 if (caf->bytes_per_packet > 0 && caf->frames_per_packet > 0) {

313 if (caf->data_size > 0)

314 st->nb_frames = (caf->data_size / caf->bytes_per_packet) * caf->frames_per_packet;

315 } else if (st->nb_index_entries && st->duration > 0) {

316 st->codec->bit_rate = st->codec->sample_rate * caf->data_size * 8 /

317 st->duration;

318 } else {

319 av_log(s, AV_LOG_ERROR, "Missing packet table. It is required when "

320 "block size or frame size are variable.\n");

321 return AVERROR_INVALIDDATA;

322 }

323

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

325 st->start_time = 0;

326

327 /* position the stream at the start of data */

328 if (caf->data_size >= 0)

329 avio_seek(pb, caf->data_start, SEEK_SET);

330

331 return 0;

332 }

333

334 #define CAF_MAX_PKT_SIZE 4096

335

336 static int read_packet(AVFormatContext *s, AVPacket *pkt)

337 {

338 AVIOContext *pb = s->pb;

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

340 CaffContext *caf = s->priv_data;

341 int res, pkt_size = 0, pkt_frames = 0;

342 int64_t left = CAF_MAX_PKT_SIZE;

343

344 if (url_feof(pb))

345 return AVERROR_EOF;

346

347 /* don't read past end of data chunk */

348 if (caf->data_size > 0) {

349 left = (caf->data_start + caf->data_size) - avio_tell(pb);

350 if (!left)

351 return AVERROR_EOF;

352 if (left < 0)

353 return AVERROR(EIO);

354 }

355

356 pkt_frames = caf->frames_per_packet;

357 pkt_size = caf->bytes_per_packet;

358

359 if (pkt_size > 0 && pkt_frames == 1) {

360 pkt_size = (CAF_MAX_PKT_SIZE / pkt_size) * pkt_size;

361 pkt_size = FFMIN(pkt_size, left);

362 pkt_frames = pkt_size / caf->bytes_per_packet;

363 } else if (st->nb_index_entries) {

364 if (caf->packet_cnt < st->nb_index_entries - 1) {

365 pkt_size = st->index_entries[caf->packet_cnt + 1].pos - st->index_entries[caf->packet_cnt].pos;

366 pkt_frames = st->index_entries[caf->packet_cnt + 1].timestamp - st->index_entries[caf->packet_cnt].timestamp;

367 } else if (caf->packet_cnt == st->nb_index_entries - 1) {

368 pkt_size = caf->num_bytes - st->index_entries[caf->packet_cnt].pos;

369 pkt_frames = st->duration - st->index_entries[caf->packet_cnt].timestamp;

370 } else {

371 return AVERROR(EIO);

372 }

373 }

374

375 if (pkt_size == 0 || pkt_frames == 0 || pkt_size > left)

376 return AVERROR(EIO);

377

378 res = av_get_packet(pb, pkt, pkt_size);

379 if (res < 0)

380 return res;

381

382 pkt->size = res;

383 pkt->stream_index = 0;

384 pkt->dts = pkt->pts = caf->frame_cnt;

385

386 caf->packet_cnt++;

387 caf->frame_cnt += pkt_frames;

388

389 return 0;

390 }

391

392 static int read_seek(AVFormatContext *s, int stream_index,

393 int64_t timestamp, int flags)

394 {

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

396 CaffContext *caf = s->priv_data;

397 int64_t pos, packet_cnt, frame_cnt;

398

399 timestamp = FFMAX(timestamp, 0);

400

401 if (caf->frames_per_packet > 0 && caf->bytes_per_packet > 0) {

402 /* calculate new byte position based on target frame position */

403 pos = caf->bytes_per_packet * (timestamp / caf->frames_per_packet);

404 if (caf->data_size > 0)

405 pos = FFMIN(pos, caf->data_size);

406 packet_cnt = pos / caf->bytes_per_packet;

407 frame_cnt = caf->frames_per_packet * packet_cnt;

408 } else if (st->nb_index_entries) {

409 packet_cnt = av_index_search_timestamp(st, timestamp, flags);

410 frame_cnt = st->index_entries[packet_cnt].timestamp;

411 pos = st->index_entries[packet_cnt].pos;

412 } else {

413 return -1;

414 }

415

416 if (avio_seek(s->pb, pos + caf->data_start, SEEK_SET) < 0)

417 return -1;

418

419 caf->packet_cnt = packet_cnt;

420 caf->frame_cnt = frame_cnt;

421

422 return 0;

423 }

424

425 AVInputFormat ff_caf_demuxer = {

426 .name = "caf",

427 .long_name = NULL_IF_CONFIG_SMALL("Apple CAF (Core Audio Format)"),

428 .priv_data_size = sizeof(CaffContext),

429 .read_probe = probe,

430 .read_header = read_header,

431 .read_packet = read_packet,

432 .read_seek = read_seek,

433 .codec_tag = (const AVCodecTag* const []){ ff_codec_caf_tags, 0 },

434 };

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