FFmpeg: libavformat/spdifenc.c Source File

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libavformat

spdifenc.c

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1 /*

2 * IEC 61937 muxer

6 *

7 * This file is part of FFmpeg.

8 *

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

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

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

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

13 *

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

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

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

17 * Lesser General Public License for more details.

18 *

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

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

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

22 */

24 /**

25 * @file

26 * IEC-61937 encapsulation of various formats, used by S/PDIF

27 * @author Bartlomiej Wolowiec

28 * @author Anssi Hannula

29 * @author Carl Eugen Hoyos

30 */

32 /*

33 * Terminology used in specification:

34 * data-burst - IEC61937 frame, contains header and encapsuled frame

35 * burst-preambule - IEC61937 frame header, contains 16-bits words named Pa, Pb, Pc and Pd

36 * burst-payload - encapsuled frame

37 * Pa, Pb - syncword - 0xF872, 0x4E1F

38 * Pc - burst-info, contains data-type (bits 0-6), error flag (bit 7), data-type-dependent info (bits 8-12)

39 * and bitstream number (bits 13-15)

40 * data-type - determines type of encapsuled frames

41 * Pd - length code (number of bits or bytes of encapsuled frame - according to data_type)

42 *

43 * IEC 61937 frames at normal usage start every specific count of bytes,

44 * dependent from data-type (spaces between packets are filled by zeros)

45 */

47 #include "avformat.h"

48 #include "avio_internal.h"

49 #include "spdif.h"

50 #include "libavcodec/ac3.h"

51 #include "libavcodec/dca.h"

52 #include "libavcodec/aacadtsdec.h"

53 #include "libavutil/opt.h"

55 typedef struct IEC61937Context {

56 const AVClass *av_class;

57 enum IEC61937DataType data_type;///< burst info - reference to type of payload of the data-burst

58 int length_code; ///< length code in bits or bytes, depending on data type

59 int pkt_offset; ///< data burst repetition period in bytes

60 uint8_t *buffer; ///< allocated buffer, used for swap bytes

61 int buffer_size; ///< size of allocated buffer

63 uint8_t *out_buf; ///< pointer to the outgoing data before byte-swapping

64 int out_bytes; ///< amount of outgoing bytes

66 int use_preamble; ///< preamble enabled (disabled for exactly pre-padded DTS)

67 int extra_bswap; ///< extra bswap for payload (for LE DTS => standard BE DTS)

69 uint8_t *hd_buf; ///< allocated buffer to concatenate hd audio frames

70 int hd_buf_size; ///< size of the hd audio buffer

71 int hd_buf_count; ///< number of frames in the hd audio buffer

72 int hd_buf_filled; ///< amount of bytes in the hd audio buffer

74 int dtshd_skip; ///< counter used for skipping DTS-HD frames

76 /* AVOptions: */

77 int dtshd_rate;

78 int dtshd_fallback;

79 #define SPDIF_FLAG_BIGENDIAN 0x01

80 int spdif_flags;

82 /// function, which generates codec dependent header information.

83 /// Sets data_type and pkt_offset, and length_code, out_bytes, out_buf if necessary

84 int (*header_info) (AVFormatContext *s, AVPacket *pkt);

85 } IEC61937Context;

87 static const AVOption options[] = {

88 { "spdif_flags", "IEC 61937 encapsulation flags", offsetof(IEC61937Context, spdif_flags), AV_OPT_TYPE_FLAGS, {.i64 = 0}, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "spdif_flags" },

89 { "be", "output in big-endian format (for use as s16be)", 0, AV_OPT_TYPE_CONST, {.i64 = SPDIF_FLAG_BIGENDIAN}, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "spdif_flags" },

90 { "dtshd_rate", "mux complete DTS frames in HD mode at the specified IEC958 rate (in Hz, default 0=disabled)", offsetof(IEC61937Context, dtshd_rate), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 768000, AV_OPT_FLAG_ENCODING_PARAM },

91 { "dtshd_fallback_time", "min secs to strip HD for after an overflow (-1: till the end, default 60)", offsetof(IEC61937Context, dtshd_fallback), AV_OPT_TYPE_INT, {.i64 = 60}, -1, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },

92 { NULL },

93 };

95 static const AVClass spdif_class = {

96 .class_name = "spdif",

97 .item_name = av_default_item_name,

98 .option = options,

99 .version = LIBAVUTIL_VERSION_INT,

100 };

101

102 static int spdif_header_ac3(AVFormatContext *s, AVPacket *pkt)

103 {

104 IEC61937Context *ctx = s->priv_data;

105 int bitstream_mode = pkt->data[5] & 0x7;

106

107 ctx->data_type = IEC61937_AC3 | (bitstream_mode << 8);

108 ctx->pkt_offset = AC3_FRAME_SIZE << 2;

109 return 0;

110 }

111

112 static int spdif_header_eac3(AVFormatContext *s, AVPacket *pkt)

113 {

114 IEC61937Context *ctx = s->priv_data;

115 static const uint8_t eac3_repeat[4] = {6, 3, 2, 1};

116 int repeat = 1;

117

118 if ((pkt->data[4] & 0xc0) != 0xc0) /* fscod */

119 repeat = eac3_repeat[(pkt->data[4] & 0x30) >> 4]; /* numblkscod */

120

121 ctx->hd_buf = av_fast_realloc(ctx->hd_buf, &ctx->hd_buf_size, ctx->hd_buf_filled + pkt->size);

122 if (!ctx->hd_buf)

123 return AVERROR(ENOMEM);

124

125 memcpy(&ctx->hd_buf[ctx->hd_buf_filled], pkt->data, pkt->size);

126

127 ctx->hd_buf_filled += pkt->size;

128 if (++ctx->hd_buf_count < repeat){

129 ctx->pkt_offset = 0;

130 return 0;

131 }

132 ctx->data_type = IEC61937_EAC3;

133 ctx->pkt_offset = 24576;

134 ctx->out_buf = ctx->hd_buf;

135 ctx->out_bytes = ctx->hd_buf_filled;

136 ctx->length_code = ctx->hd_buf_filled;

137

138 ctx->hd_buf_count = 0;

139 ctx->hd_buf_filled = 0;

140 return 0;

141 }

142

143 /*

144 * DTS type IV (DTS-HD) can be transmitted with various frame repetition

145 * periods; longer repetition periods allow for longer packets and therefore

146 * higher bitrate. Longer repetition periods mean that the constant bitrate of

147 * the outputted IEC 61937 stream is higher.

148 * The repetition period is measured in IEC 60958 frames (4 bytes).

149 */

150 static int spdif_dts4_subtype(int period)

151 {

152 switch (period) {

153 case 512: return 0x0;

154 case 1024: return 0x1;

155 case 2048: return 0x2;

156 case 4096: return 0x3;

157 case 8192: return 0x4;

158 case 16384: return 0x5;

159 }

160 return -1;

161 }

162

163 static int spdif_header_dts4(AVFormatContext *s, AVPacket *pkt, int core_size,

164 int sample_rate, int blocks)

165 {

166 IEC61937Context *ctx = s->priv_data;

167 static const char dtshd_start_code[10] = { 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xfe, 0xfe };

168 int pkt_size = pkt->size;

169 int period;

170 int subtype;

171

172 if (!core_size) {

173 av_log(s, AV_LOG_ERROR, "HD mode not supported for this format\n");

174 return AVERROR(EINVAL);

175 }

176

177 if (!sample_rate) {

178 av_log(s, AV_LOG_ERROR, "Unknown DTS sample rate for HD\n");

179 return AVERROR_INVALIDDATA;

180 }

181

182 period = ctx->dtshd_rate * (blocks << 5) / sample_rate;

183 subtype = spdif_dts4_subtype(period);

184

185 if (subtype < 0) {

186 av_log(s, AV_LOG_ERROR, "Specified HD rate of %d Hz would require an "

187 "impossible repetition period of %d for the current DTS stream"

188 " (blocks = %d, sample rate = %d)\n", ctx->dtshd_rate, period,

189 blocks << 5, sample_rate);

190 return AVERROR(EINVAL);

191 }

192

193 /* set pkt_offset and DTS IV subtype according to the requested output

194 * rate */

195 ctx->pkt_offset = period * 4;

196 ctx->data_type = IEC61937_DTSHD | subtype << 8;

197

198 /* If the bitrate is too high for transmitting at the selected

199 * repetition period setting, strip DTS-HD until a good amount

200 * of consecutive non-overflowing HD frames have been observed.

201 * This generally only happens if the caller is cramming a Master

202 * Audio stream into 192kHz IEC 60958 (which may or may not fit). */

203 if (sizeof(dtshd_start_code) + 2 + pkt_size

204 > ctx->pkt_offset - BURST_HEADER_SIZE && core_size) {

205 if (!ctx->dtshd_skip)

206 av_log(s, AV_LOG_WARNING, "DTS-HD bitrate too high, "

207 "temporarily sending core only\n");

208 if (ctx->dtshd_fallback > 0)

209 ctx->dtshd_skip = sample_rate * ctx->dtshd_fallback / (blocks << 5);

210 else

211 /* skip permanently (dtshd_fallback == -1) or just once

212 * (dtshd_fallback == 0) */

213 ctx->dtshd_skip = 1;

214 }

215 if (ctx->dtshd_skip && core_size) {

216 pkt_size = core_size;

217 if (ctx->dtshd_fallback >= 0)

218 --ctx->dtshd_skip;

219 }

220

221 ctx->out_bytes = sizeof(dtshd_start_code) + 2 + pkt_size;

222

223 /* Align so that (length_code & 0xf) == 0x8. This is reportedly needed

224 * with some receivers, but the exact requirement is unconfirmed. */

225 ctx->length_code = FFALIGN(ctx->out_bytes + 0x8, 0x10) - 0x8;

226

227 av_fast_malloc(&ctx->hd_buf, &ctx->hd_buf_size, ctx->out_bytes);

228 if (!ctx->hd_buf)

229 return AVERROR(ENOMEM);

230

231 ctx->out_buf = ctx->hd_buf;

232

233 memcpy(ctx->hd_buf, dtshd_start_code, sizeof(dtshd_start_code));

234 AV_WB16(ctx->hd_buf + sizeof(dtshd_start_code), pkt_size);

235 memcpy(ctx->hd_buf + sizeof(dtshd_start_code) + 2, pkt->data, pkt_size);

236

237 return 0;

238 }

239

240 static int spdif_header_dts(AVFormatContext *s, AVPacket *pkt)

241 {

242 IEC61937Context *ctx = s->priv_data;

243 uint32_t syncword_dts = AV_RB32(pkt->data);

244 int blocks;

245 int sample_rate = 0;

246 int core_size = 0;

247

248 if (pkt->size < 9)

249 return AVERROR_INVALIDDATA;

250

251 switch (syncword_dts) {

252 case DCA_MARKER_RAW_BE:

253 blocks = (AV_RB16(pkt->data + 4) >> 2) & 0x7f;

254 core_size = ((AV_RB24(pkt->data + 5) >> 4) & 0x3fff) + 1;

255 sample_rate = avpriv_dca_sample_rates[(pkt->data[8] >> 2) & 0x0f];

256 break;

257 case DCA_MARKER_RAW_LE:

258 blocks = (AV_RL16(pkt->data + 4) >> 2) & 0x7f;

259 ctx->extra_bswap = 1;

260 break;

261 case DCA_MARKER_14B_BE:

262 blocks =

263 (((pkt->data[5] & 0x07) << 4) | ((pkt->data[6] & 0x3f) >> 2));

264 break;

265 case DCA_MARKER_14B_LE:

266 blocks =

267 (((pkt->data[4] & 0x07) << 4) | ((pkt->data[7] & 0x3f) >> 2));

268 ctx->extra_bswap = 1;

269 break;

270 case DCA_HD_MARKER:

271 /* We only handle HD frames that are paired with core. However,

272 sometimes DTS-HD streams with core have a stray HD frame without

273 core in the beginning of the stream. */

274 av_log(s, AV_LOG_ERROR, "stray DTS-HD frame\n");

275 return AVERROR_INVALIDDATA;

276 default:

277 av_log(s, AV_LOG_ERROR, "bad DTS syncword 0x%x\n", syncword_dts);

278 return AVERROR_INVALIDDATA;

279 }

280 blocks++;

281

282 if (ctx->dtshd_rate)

283 /* DTS type IV output requested */

284 return spdif_header_dts4(s, pkt, core_size, sample_rate, blocks);

285

286 switch (blocks) {

287 case 512 >> 5: ctx->data_type = IEC61937_DTS1; break;

288 case 1024 >> 5: ctx->data_type = IEC61937_DTS2; break;

289 case 2048 >> 5: ctx->data_type = IEC61937_DTS3; break;

290 default:

291 av_log(s, AV_LOG_ERROR, "%i samples in DTS frame not supported\n",

292 blocks << 5);

293 return AVERROR(ENOSYS);

294 }

295

296 /* discard extraneous data by default */

297 if (core_size && core_size < pkt->size) {

298 ctx->out_bytes = core_size;

299 ctx->length_code = core_size << 3;

300 }

301

302 ctx->pkt_offset = blocks << 7;

303

304 if (ctx->out_bytes == ctx->pkt_offset) {

305 /* The DTS stream fits exactly into the output stream, so skip the

306 * preamble as it would not fit in there. This is the case for dts

307 * discs and dts-in-wav. */

308 ctx->use_preamble = 0;

309 } else if (ctx->out_bytes > ctx->pkt_offset - BURST_HEADER_SIZE) {

310 avpriv_request_sample(s, "Unrecognized large DTS frame");

311 /* This will fail with a "bitrate too high" in the caller */

312 }

313

314 return 0;

315 }

316

317 static const enum IEC61937DataType mpeg_data_type[2][3] = {

318 // LAYER1 LAYER2 LAYER3

319 { IEC61937_MPEG2_LAYER1_LSF, IEC61937_MPEG2_LAYER2_LSF, IEC61937_MPEG2_LAYER3_LSF },//MPEG2 LSF

320 { IEC61937_MPEG1_LAYER1, IEC61937_MPEG1_LAYER23, IEC61937_MPEG1_LAYER23 }, //MPEG1

321 };

322

323 static int spdif_header_mpeg(AVFormatContext *s, AVPacket *pkt)

324 {

325 IEC61937Context *ctx = s->priv_data;

326 int version = (pkt->data[1] >> 3) & 3;

327 int layer = 3 - ((pkt->data[1] >> 1) & 3);

328 int extension = pkt->data[2] & 1;

329

330 if (layer == 3 || version == 1) {

331 av_log(s, AV_LOG_ERROR, "Wrong MPEG file format\n");

332 return AVERROR_INVALIDDATA;

333 }

334 av_log(s, AV_LOG_DEBUG, "version: %i layer: %i extension: %i\n", version, layer, extension);

335 if (version == 2 && extension) {

336 ctx->data_type = IEC61937_MPEG2_EXT;

337 ctx->pkt_offset = 4608;

338 } else {

339 ctx->data_type = mpeg_data_type [version & 1][layer];

340 ctx->pkt_offset = spdif_mpeg_pkt_offset[version & 1][layer];

341 }

342 // TODO Data type dependent info (normal/karaoke, dynamic range control)

343 return 0;

344 }

345

346 static int spdif_header_aac(AVFormatContext *s, AVPacket *pkt)

347 {

348 IEC61937Context *ctx = s->priv_data;

349 AACADTSHeaderInfo hdr;

350 GetBitContext gbc;

351 int ret;

352

353 init_get_bits(&gbc, pkt->data, AAC_ADTS_HEADER_SIZE * 8);

354 ret = avpriv_aac_parse_header(&gbc, &hdr);

355 if (ret < 0) {

356 av_log(s, AV_LOG_ERROR, "Wrong AAC file format\n");

357 return AVERROR_INVALIDDATA;

358 }

359

360 ctx->pkt_offset = hdr.samples << 2;

361 switch (hdr.num_aac_frames) {

362 case 1:

363 ctx->data_type = IEC61937_MPEG2_AAC;

364 break;

365 case 2:

366 ctx->data_type = IEC61937_MPEG2_AAC_LSF_2048;

367 break;

368 case 4:

369 ctx->data_type = IEC61937_MPEG2_AAC_LSF_4096;

370 break;

371 default:

372 av_log(s, AV_LOG_ERROR, "%i samples in AAC frame not supported\n",

373 hdr.samples);

374 return AVERROR(EINVAL);

375 }

376 //TODO Data type dependent info (LC profile/SBR)

377 return 0;

378 }

379

380

381 /*

382 * It seems Dolby TrueHD frames have to be encapsulated in MAT frames before

383 * they can be encapsulated in IEC 61937.

384 * Here we encapsulate 24 TrueHD frames in a single MAT frame, padding them

385 * to achieve constant rate.

386 * The actual format of a MAT frame is unknown, but the below seems to work.

387 * However, it seems it is not actually necessary for the 24 TrueHD frames to

388 * be in an exact alignment with the MAT frame.

389 */

390 #define MAT_FRAME_SIZE 61424

391 #define TRUEHD_FRAME_OFFSET 2560

392 #define MAT_MIDDLE_CODE_OFFSET -4

393

394 static int spdif_header_truehd(AVFormatContext *s, AVPacket *pkt)

395 {

396 IEC61937Context *ctx = s->priv_data;

397 int mat_code_length = 0;

398 const char mat_end_code[16] = { 0xC3, 0xC2, 0xC0, 0xC4, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x97, 0x11 };

399

400 if (!ctx->hd_buf_count) {

401 const char mat_start_code[20] = { 0x07, 0x9E, 0x00, 0x03, 0x84, 0x01, 0x01, 0x01, 0x80, 0x00, 0x56, 0xA5, 0x3B, 0xF4, 0x81, 0x83, 0x49, 0x80, 0x77, 0xE0 };

402 mat_code_length = sizeof(mat_start_code) + BURST_HEADER_SIZE;

403 memcpy(ctx->hd_buf, mat_start_code, sizeof(mat_start_code));

404

405 } else if (ctx->hd_buf_count == 12) {

406 const char mat_middle_code[12] = { 0xC3, 0xC1, 0x42, 0x49, 0x3B, 0xFA, 0x82, 0x83, 0x49, 0x80, 0x77, 0xE0 };

407 mat_code_length = sizeof(mat_middle_code) + MAT_MIDDLE_CODE_OFFSET;

408 memcpy(&ctx->hd_buf[12 * TRUEHD_FRAME_OFFSET - BURST_HEADER_SIZE + MAT_MIDDLE_CODE_OFFSET],

409 mat_middle_code, sizeof(mat_middle_code));

410 }

411

412 if (pkt->size > TRUEHD_FRAME_OFFSET - mat_code_length) {

413 /* if such frames exist, we'd need some more complex logic to