FFmpeg: libavcodec/mlp_parser.c Source File

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libavcodec

mlp_parser.c

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1 /*

2 * MLP parser

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 * MLP parser

25 */

27 #include <stdint.h>

29 #include "libavutil/channel_layout.h"

30 #include "libavutil/crc.h"

31 #include "libavutil/internal.h"

32 #include "get_bits.h"

33 #include "parser.h"

34 #include "mlp_parser.h"

35 #include "mlp.h"

37 static const uint8_t mlp_quants[16] = {

38 16, 20, 24, 0, 0, 0, 0, 0,

39 0, 0, 0, 0, 0, 0, 0, 0,

40 };

42 static const uint8_t mlp_channels[32] = {

43 1, 2, 3, 4, 3, 4, 5, 3, 4, 5, 4, 5, 6, 4, 5, 4,

44 5, 6, 5, 5, 6, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

45 };

47 const uint64_t ff_mlp_layout[32] = {

48 AV_CH_LAYOUT_MONO,

49 AV_CH_LAYOUT_STEREO,

50 AV_CH_LAYOUT_2_1,

51 AV_CH_LAYOUT_QUAD,

52 AV_CH_LAYOUT_STEREO|AV_CH_LOW_FREQUENCY,

53 AV_CH_LAYOUT_2_1|AV_CH_LOW_FREQUENCY,

54 AV_CH_LAYOUT_QUAD|AV_CH_LOW_FREQUENCY,

55 AV_CH_LAYOUT_SURROUND,

56 AV_CH_LAYOUT_4POINT0,

57 AV_CH_LAYOUT_5POINT0_BACK,

58 AV_CH_LAYOUT_SURROUND|AV_CH_LOW_FREQUENCY,

59 AV_CH_LAYOUT_4POINT0|AV_CH_LOW_FREQUENCY,

60 AV_CH_LAYOUT_5POINT1_BACK,

61 AV_CH_LAYOUT_4POINT0,

62 AV_CH_LAYOUT_5POINT0_BACK,

63 AV_CH_LAYOUT_SURROUND|AV_CH_LOW_FREQUENCY,

64 AV_CH_LAYOUT_4POINT0|AV_CH_LOW_FREQUENCY,

65 AV_CH_LAYOUT_5POINT1_BACK,

66 AV_CH_LAYOUT_QUAD|AV_CH_LOW_FREQUENCY,

67 AV_CH_LAYOUT_5POINT0_BACK,

68 AV_CH_LAYOUT_5POINT1_BACK,

69 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

70 };

72 static const uint8_t thd_chancount[13] = {

73 // LR C LFE LRs LRvh LRc LRrs Cs Ts LRsd LRw Cvh LFE2

74 2, 1, 1, 2, 2, 2, 2, 1, 1, 2, 2, 1, 1

75 };

77 static const uint64_t thd_layout[13] = {

78 AV_CH_FRONT_LEFT|AV_CH_FRONT_RIGHT, // LR

79 AV_CH_FRONT_CENTER, // C

80 AV_CH_LOW_FREQUENCY, // LFE

81 AV_CH_SIDE_LEFT|AV_CH_SIDE_RIGHT, // LRs

82 AV_CH_TOP_FRONT_LEFT|AV_CH_TOP_FRONT_RIGHT, // LRvh

83 AV_CH_FRONT_LEFT_OF_CENTER|AV_CH_FRONT_RIGHT_OF_CENTER, // LRc

84 AV_CH_BACK_LEFT|AV_CH_BACK_RIGHT, // LRrs

85 AV_CH_BACK_CENTER, // Cs

86 AV_CH_TOP_CENTER, // Ts

87 AV_CH_SURROUND_DIRECT_LEFT|AV_CH_SURROUND_DIRECT_RIGHT, // LRsd

88 AV_CH_WIDE_LEFT|AV_CH_WIDE_RIGHT, // LRw

89 AV_CH_TOP_FRONT_CENTER, // Cvh

90 AV_CH_LOW_FREQUENCY_2, // LFE2

91 };

93 static int mlp_samplerate(int in)

94 {

95 if (in == 0xF)

96 return 0;

98 return (in & 8 ? 44100 : 48000) << (in & 7) ;

99 }

100

101 static int truehd_channels(int chanmap)

102 {

103 int channels = 0, i;

104

105 for (i = 0; i < 13; i++)

106 channels += thd_chancount[i] * ((chanmap >> i) & 1);

107

108 return channels;

109 }

110

111 uint64_t ff_truehd_layout(int chanmap)

112 {

113 int i;

114 uint64_t layout = 0;

115

116 for (i = 0; i < 13; i++)

117 layout |= thd_layout[i] * ((chanmap >> i) & 1);

118

119 return layout;

120 }

121

122 static int ff_mlp_get_major_sync_size(const uint8_t * buf, int bufsize)

123 {

124 int has_extension, extensions = 0;

125 int size = 28;

126 if (bufsize < 28)

127 return -1;

128

129 if (AV_RB32(buf) == 0xf8726fba) {

130 has_extension = buf[25] & 1;

131 if (has_extension) {

132 extensions = buf[26] >> 4;

133 size += 2 + extensions * 2;

134 }

135 }

136 return size;

137 }

138

139 /** Read a major sync info header - contains high level information about

140 * the stream - sample rate, channel arrangement etc. Most of this

141 * information is not actually necessary for decoding, only for playback.

142 * gb must be a freshly initialized GetBitContext with no bits read.

143 */

144

145 int ff_mlp_read_major_sync(void *log, MLPHeaderInfo *mh, GetBitContext *gb)

146 {

147 int ratebits, channel_arrangement, header_size;

148 uint16_t checksum;

149

150 av_assert1(get_bits_count(gb) == 0);

151

152 header_size = ff_mlp_get_major_sync_size(gb->buffer, gb->size_in_bits >> 3);

153 if (header_size < 0 || gb->size_in_bits < header_size << 3) {

154 av_log(log, AV_LOG_ERROR, "packet too short, unable to read major sync\n");

155 return -1;

156 }

157

158 checksum = ff_mlp_checksum16(gb->buffer, header_size - 2);

159 if (checksum != AV_RL16(gb->buffer+header_size-2)) {

160 av_log(log, AV_LOG_ERROR, "major sync info header checksum error\n");

161 return AVERROR_INVALIDDATA;

162 }

163

164 if (get_bits_long(gb, 24) != 0xf8726f) /* Sync words */

165 return AVERROR_INVALIDDATA;

166

167 mh->stream_type = get_bits(gb, 8);

168 mh->header_size = header_size;

169

170 if (mh->stream_type == 0xbb) {

171 mh->group1_bits = mlp_quants[get_bits(gb, 4)];

172 mh->group2_bits = mlp_quants[get_bits(gb, 4)];

173

174 ratebits = get_bits(gb, 4);

175 mh->group1_samplerate = mlp_samplerate(ratebits);

176 mh->group2_samplerate = mlp_samplerate(get_bits(gb, 4));

177

178 skip_bits(gb, 11);

179

180 mh->channel_arrangement=

181 channel_arrangement = get_bits(gb, 5);

182 mh->channels_mlp = mlp_channels[channel_arrangement];

183 mh->channel_layout_mlp = ff_mlp_layout[channel_arrangement];

184 } else if (mh->stream_type == 0xba) {

185 mh->group1_bits = 24; // TODO: Is this information actually conveyed anywhere?

186 mh->group2_bits = 0;

187

188 ratebits = get_bits(gb, 4);

189 mh->group1_samplerate = mlp_samplerate(ratebits);

190 mh->group2_samplerate = 0;

191

192 skip_bits(gb, 4);

193

194 mh->channel_modifier_thd_stream0 = get_bits(gb, 2);

195 mh->channel_modifier_thd_stream1 = get_bits(gb, 2);

196

197 mh->channel_arrangement=

198 channel_arrangement = get_bits(gb, 5);

199 mh->channels_thd_stream1 = truehd_channels(channel_arrangement);

200 mh->channel_layout_thd_stream1 = ff_truehd_layout(channel_arrangement);

201

202 mh->channel_modifier_thd_stream2 = get_bits(gb, 2);

203

204 channel_arrangement = get_bits(gb, 13);

205 mh->channels_thd_stream2 = truehd_channels(channel_arrangement);

206 mh->channel_layout_thd_stream2 = ff_truehd_layout(channel_arrangement);

207 } else

208 return AVERROR_INVALIDDATA;

209

210 mh->access_unit_size = 40 << (ratebits & 7);

211 mh->access_unit_size_pow2 = 64 << (ratebits & 7);

212

213 skip_bits_long(gb, 48);

214

215 mh->is_vbr = get_bits1(gb);

216

217 mh->peak_bitrate = (get_bits(gb, 15) * mh->group1_samplerate + 8) >> 4;

218

219 mh->num_substreams = get_bits(gb, 4);

220

221 skip_bits_long(gb, 4 + (header_size - 17) * 8);

222

223 return 0;

224 }

225

226 typedef struct MLPParseContext

227 {

228 ParseContext pc;

229

230 int bytes_left;

231

232 int in_sync;

233

234 int num_substreams;

235 } MLPParseContext;

236

237 static av_cold int mlp_init(AVCodecParserContext *s)

238 {

239 ff_mlp_init_crc();

240 return 0;

241 }

242

243 static int mlp_parse(AVCodecParserContext *s,

244 AVCodecContext *avctx,

245 const uint8_t **poutbuf, int *poutbuf_size,

246 const uint8_t *buf, int buf_size)

247 {

248 MLPParseContext *mp = s->priv_data;

249 int sync_present;

250 uint8_t parity_bits;

251 int next;

252 int ret;

253 int i, p = 0;

254

255 *poutbuf_size = 0;

256 if (buf_size == 0)

257 return 0;

258

259 if (!mp->in_sync) {

260 // Not in sync - find a major sync header

261

262 for (i = 0; i < buf_size; i++) {

263 mp->pc.state = (mp->pc.state << 8) | buf[i];

264 if ((mp->pc.state & 0xfffffffe) == 0xf8726fba &&

265 // ignore if we do not have the data for the start of header

266 mp->pc.index + i >= 7) {

267 mp->in_sync = 1;

268 mp->bytes_left = 0;

269 break;

270 }

271 }

272

273 if (!mp->in_sync) {

274 if (ff_combine_frame(&mp->pc, END_NOT_FOUND, &buf, &buf_size) != -1)

275 av_log(avctx, AV_LOG_WARNING, "ff_combine_frame failed\n");

276 return buf_size;

277 }

278

279 if ((ret = ff_combine_frame(&mp->pc, i - 7, &buf, &buf_size)) < 0) {

280 av_log(avctx, AV_LOG_WARNING, "ff_combine_frame failed\n");

281 return ret;

282 }

283

284 return i - 7;

285 }

286

287 if (mp->bytes_left == 0) {

288 // Find length of this packet

289

290 /* Copy overread bytes from last frame into buffer. */

291 for(; mp->pc.overread>0; mp->pc.overread--) {

292 mp->pc.buffer[mp->pc.index++]= mp->pc.buffer[mp->pc.overread_index++];

293 }

294

295 if (mp->pc.index + buf_size < 2) {

296 if (ff_combine_frame(&mp->pc, END_NOT_FOUND, &buf, &buf_size) != -1)

297 av_log(avctx, AV_LOG_WARNING, "ff_combine_frame failed\n");

298 return buf_size;

299 }

300

301 mp->bytes_left = ((mp->pc.index > 0 ? mp->pc.buffer[0] : buf[0]) << 8)

302 | (mp->pc.index > 1 ? mp->pc.buffer[1] : buf[1-mp->pc.index]);

303 mp->bytes_left = (mp->bytes_left & 0xfff) * 2;

304 if (mp->bytes_left <= 0) { // prevent infinite loop

305 goto lost_sync;

306 }

307 mp->bytes_left -= mp->pc.index;

308 }

309

310 next = (mp->bytes_left > buf_size) ? END_NOT_FOUND : mp->bytes_left;

311

312 if (ff_combine_frame(&mp->pc, next, &buf, &buf_size) < 0) {

313 mp->bytes_left -= buf_size;

314 return buf_size;

315 }

316

317 mp->bytes_left = 0;

318

319 sync_present = (AV_RB32(buf + 4) & 0xfffffffe) == 0xf8726fba;

320

321 if (!sync_present) {

322 /* The first nibble of a frame is a parity check of the 4-byte

323 * access unit header and all the 2- or 4-byte substream headers. */

324 // Only check when this isn't a sync frame - syncs have a checksum.

325

326 parity_bits = 0;

327 for (i = -1; i < mp->num_substreams; i++) {

328 parity_bits ^= buf[p++];

329 parity_bits ^= buf[p++];

330

331 if (i < 0 || buf[p-2] & 0x80) {

332 parity_bits ^= buf[p++];

333 parity_bits ^= buf[p++];

334 }

335 }

336

337 if ((((parity_bits >> 4) ^ parity_bits) & 0xF) != 0xF) {

338 av_log(avctx, AV_LOG_INFO, "mlpparse: Parity check failed.\n");

339 goto lost_sync;

340 }

341 } else {

342 GetBitContext gb;

343 MLPHeaderInfo mh;

344

345 init_get_bits(&gb, buf + 4, (buf_size - 4) << 3);

346 if (ff_mlp_read_major_sync(avctx, &mh, &gb) < 0)

347 goto lost_sync;

348

349 avctx->bits_per_raw_sample = mh.group1_bits;

350 if (avctx->bits_per_raw_sample > 16)

351 avctx->sample_fmt = AV_SAMPLE_FMT_S32;

352 else

353 avctx->sample_fmt = AV_SAMPLE_FMT_S16;

354 avctx->sample_rate = mh.group1_samplerate;

355 s->duration = mh.access_unit_size;

356

357 if(!avctx->channels || !avctx->channel_layout) {

358 if (mh.stream_type == 0xbb) {

359 /* MLP stream */

360 #if FF_API_REQUEST_CHANNELS

361 FF_DISABLE_DEPRECATION_WARNINGS

362 if (avctx->request_channels > 0 && avctx->request_channels <= 2 &&

363 mh.num_substreams > 1) {

364 avctx->channels = 2;

365 avctx->channel_layout = AV_CH_LAYOUT_STEREO;

366 FF_ENABLE_DEPRECATION_WARNINGS

367 } else

368 #endif

369 if (avctx->request_channel_layout &&

370 (avctx->request_channel_layout & AV_CH_LAYOUT_STEREO) ==

371 avctx->request_channel_layout &&

372 mh.num_substreams > 1) {

373 avctx->channels = 2;

374 avctx->channel_layout = AV_CH_LAYOUT_STEREO;

375 } else {

376 avctx->channels = mh.channels_mlp;

377 avctx->channel_layout = mh.channel_layout_mlp;

378 }

379 } else { /* mh.stream_type == 0xba */

380 /* TrueHD stream */

381 #if FF_API_REQUEST_CHANNELS

382 FF_DISABLE_DEPRECATION_WARNINGS

383 if (avctx->request_channels > 0 && avctx->request_channels <= 2 &&

384 mh.num_substreams > 1) {

385 avctx->channels = 2;

386 avctx->channel_layout = AV_CH_LAYOUT_STEREO;

387 } else if (avctx->request_channels > 0 &&

388 avctx->request_channels <= mh.channels_thd_stream1) {

389 avctx->channels = mh.channels_thd_stream1;

390 avctx->channel_layout = mh.channel_layout_thd_stream1;

391 FF_ENABLE_DEPRECATION_WARNINGS

392 } else

393 #endif

394 if (avctx->request_channel_layout &&

395 (avctx->request_channel_layout & AV_CH_LAYOUT_STEREO) ==

396 avctx->request_channel_layout &&

397 mh.num_substreams > 1) {

398 avctx->channels = 2;

399 avctx->channel_layout = AV_CH_LAYOUT_STEREO;

400 } else if (!mh.channels_thd_stream2 ||

401 (avctx->request_channel_layout &&

402 (avctx->request_channel_layout & mh.channel_layout_thd_stream1) ==

403 avctx->request_channel_layout)) {

404 avctx->channels = mh.channels_thd_stream1;

405 avctx->channel_layout = mh.channel_layout_thd_stream1;

406 } else {

407 avctx->channels = mh.channels_thd_stream2;

408 avctx->channel_layout = mh.channel_layout_thd_stream2;

409 }

410 }

411 }

412

413 if (!mh.is_vbr) /* Stream is CBR */

414 avctx->bit_rate = mh.peak_bitrate;

415

416 mp->num_substreams = mh.num_substreams;

417 }

418

419 *poutbuf = buf;

420 *poutbuf_size = buf_size;

421

422 return next;

423

424 lost_sync:

425 mp->in_sync = 0;

426 return 1;

427 }

428

429 AVCodecParser ff_mlp_parser = {

430 .codec_ids = { AV_CODEC_ID_MLP, AV_CODEC_ID_TRUEHD },

431 .priv_data_size = sizeof(MLPParseContext),

432 .parser_init = mlp_init,

433 .parser_parse = mlp_parse,

434 .parser_close = ff_parse_close,

435 };

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