FFmpeg: libavcodec/wmaprodec.c Source File

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wmaprodec.c

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1 /*

2 * Wmapro compatible decoder

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 * @brief wmapro decoder implementation

26 * Wmapro is an MDCT based codec comparable to wma standard or AAC.

27 * The decoding therefore consists of the following steps:

28 * - bitstream decoding

29 * - reconstruction of per-channel data

30 * - rescaling and inverse quantization

31 * - IMDCT

32 * - windowing and overlapp-add

33 *

34 * The compressed wmapro bitstream is split into individual packets.

35 * Every such packet contains one or more wma frames.

36 * The compressed frames may have a variable length and frames may

37 * cross packet boundaries.

38 * Common to all wmapro frames is the number of samples that are stored in

39 * a frame.

40 * The number of samples and a few other decode flags are stored

41 * as extradata that has to be passed to the decoder.

42 *

43 * The wmapro frames themselves are again split into a variable number of

44 * subframes. Every subframe contains the data for 2^N time domain samples

45 * where N varies between 7 and 12.

46 *

47 * Example wmapro bitstream (in samples):

48 *

49 * || packet 0 || packet 1 || packet 2 packets

50 * ---------------------------------------------------

51 * || frame 0 || frame 1 || frame 2 || frames

52 * ---------------------------------------------------

53 * || | | || | | | || || subframes of channel 0

54 * ---------------------------------------------------

55 * || | | || | | | || || subframes of channel 1

56 * ---------------------------------------------------

57 *

58 * The frame layouts for the individual channels of a wma frame does not need

59 * to be the same.

60 *

61 * However, if the offsets and lengths of several subframes of a frame are the

62 * same, the subframes of the channels can be grouped.

63 * Every group may then use special coding techniques like M/S stereo coding

64 * to improve the compression ratio. These channel transformations do not

65 * need to be applied to a whole subframe. Instead, they can also work on

66 * individual scale factor bands (see below).

67 * The coefficients that carry the audio signal in the frequency domain

68 * are transmitted as huffman-coded vectors with 4, 2 and 1 elements.

69 * In addition to that, the encoder can switch to a runlevel coding scheme

70 * by transmitting subframe_length / 128 zero coefficients.

71 *

72 * Before the audio signal can be converted to the time domain, the

73 * coefficients have to be rescaled and inverse quantized.

74 * A subframe is therefore split into several scale factor bands that get

75 * scaled individually.

76 * Scale factors are submitted for every frame but they might be shared

77 * between the subframes of a channel. Scale factors are initially DPCM-coded.

78 * Once scale factors are shared, the differences are transmitted as runlevel

79 * codes.

80 * Every subframe length and offset combination in the frame layout shares a

81 * common quantization factor that can be adjusted for every channel by a

82 * modifier.

83 * After the inverse quantization, the coefficients get processed by an IMDCT.

84 * The resulting values are then windowed with a sine window and the first half

85 * of the values are added to the second half of the output from the previous

86 * subframe in order to reconstruct the output samples.

87 */

89 #include "libavutil/float_dsp.h"

90 #include "libavutil/intfloat.h"

91 #include "libavutil/intreadwrite.h"

92 #include "avcodec.h"

93 #include "internal.h"

94 #include "get_bits.h"

95 #include "put_bits.h"

96 #include "wmaprodata.h"

97 #include "sinewin.h"

98 #include "wma.h"

99 #include "wma_common.h"

100

101 /** current decoder limitations */

102 #define WMAPRO_MAX_CHANNELS 8 ///< max number of handled channels

103 #define MAX_SUBFRAMES 32 ///< max number of subframes per channel

104 #define MAX_BANDS 29 ///< max number of scale factor bands

105 #define MAX_FRAMESIZE 32768 ///< maximum compressed frame size

106

107 #define WMAPRO_BLOCK_MIN_BITS 6 ///< log2 of min block size

108 #define WMAPRO_BLOCK_MAX_BITS 13 ///< log2 of max block size

109 #define WMAPRO_BLOCK_MIN_SIZE (1 << WMAPRO_BLOCK_MIN_BITS) ///< minimum block size

110 #define WMAPRO_BLOCK_MAX_SIZE (1 << WMAPRO_BLOCK_MAX_BITS) ///< maximum block size

111 #define WMAPRO_BLOCK_SIZES (WMAPRO_BLOCK_MAX_BITS - WMAPRO_BLOCK_MIN_BITS + 1) ///< possible block sizes

112

113

114 #define VLCBITS 9

115 #define SCALEVLCBITS 8

116 #define VEC4MAXDEPTH ((HUFF_VEC4_MAXBITS+VLCBITS-1)/VLCBITS)

117 #define VEC2MAXDEPTH ((HUFF_VEC2_MAXBITS+VLCBITS-1)/VLCBITS)

118 #define VEC1MAXDEPTH ((HUFF_VEC1_MAXBITS+VLCBITS-1)/VLCBITS)

119 #define SCALEMAXDEPTH ((HUFF_SCALE_MAXBITS+SCALEVLCBITS-1)/SCALEVLCBITS)

120 #define SCALERLMAXDEPTH ((HUFF_SCALE_RL_MAXBITS+VLCBITS-1)/VLCBITS)

121

122 static VLC sf_vlc; ///< scale factor DPCM vlc

123 static VLC sf_rl_vlc; ///< scale factor run length vlc

124 static VLC vec4_vlc; ///< 4 coefficients per symbol

125 static VLC vec2_vlc; ///< 2 coefficients per symbol

126 static VLC vec1_vlc; ///< 1 coefficient per symbol

127 static VLC coef_vlc[2]; ///< coefficient run length vlc codes

128 static float sin64[33]; ///< sine table for decorrelation

129

130 /**

131 * @brief frame specific decoder context for a single channel

132 */

133 typedef struct {

134 int16_t prev_block_len; ///< length of the previous block

135 uint8_t transmit_coefs;

136 uint8_t num_subframes;

137 uint16_t subframe_len[MAX_SUBFRAMES]; ///< subframe length in samples

138 uint16_t subframe_offset[MAX_SUBFRAMES]; ///< subframe positions in the current frame

139 uint8_t cur_subframe; ///< current subframe number

140 uint16_t decoded_samples; ///< number of already processed samples

141 uint8_t grouped; ///< channel is part of a group

142 int quant_step; ///< quantization step for the current subframe

143 int8_t reuse_sf; ///< share scale factors between subframes

144 int8_t scale_factor_step; ///< scaling step for the current subframe

145 int max_scale_factor; ///< maximum scale factor for the current subframe

146 int saved_scale_factors[2][MAX_BANDS]; ///< resampled and (previously) transmitted scale factor values

147 int8_t scale_factor_idx; ///< index for the transmitted scale factor values (used for resampling)

148 int* scale_factors; ///< pointer to the scale factor values used for decoding

149 uint8_t table_idx; ///< index in sf_offsets for the scale factor reference block

150 float* coeffs; ///< pointer to the subframe decode buffer

151 uint16_t num_vec_coeffs; ///< number of vector coded coefficients

152 DECLARE_ALIGNED(32, float, out)[WMAPRO_BLOCK_MAX_SIZE + WMAPRO_BLOCK_MAX_SIZE / 2]; ///< output buffer

153 } WMAProChannelCtx;

154

155 /**

156 * @brief channel group for channel transformations

157 */

158 typedef struct {

159 uint8_t num_channels; ///< number of channels in the group

160 int8_t transform; ///< transform on / off

161 int8_t transform_band[MAX_BANDS]; ///< controls if the transform is enabled for a certain band

162 float decorrelation_matrix[WMAPRO_MAX_CHANNELS*WMAPRO_MAX_CHANNELS];

163 float* channel_data[WMAPRO_MAX_CHANNELS]; ///< transformation coefficients

164 } WMAProChannelGrp;

165

166 /**

167 * @brief main decoder context

168 */

169 typedef struct WMAProDecodeCtx {

170 /* generic decoder variables */

171 AVCodecContext* avctx; ///< codec context for av_log

172 AVFloatDSPContext fdsp;

173 uint8_t frame_data[MAX_FRAMESIZE +

174 FF_INPUT_BUFFER_PADDING_SIZE];///< compressed frame data

175 PutBitContext pb; ///< context for filling the frame_data buffer

176 FFTContext mdct_ctx[WMAPRO_BLOCK_SIZES]; ///< MDCT context per block size

177 DECLARE_ALIGNED(32, float, tmp)[WMAPRO_BLOCK_MAX_SIZE]; ///< IMDCT output buffer

178 float* windows[WMAPRO_BLOCK_SIZES]; ///< windows for the different block sizes

179

180 /* frame size dependent frame information (set during initialization) */

181 uint32_t decode_flags; ///< used compression features

182 uint8_t len_prefix; ///< frame is prefixed with its length

183 uint8_t dynamic_range_compression; ///< frame contains DRC data

184 uint8_t bits_per_sample; ///< integer audio sample size for the unscaled IMDCT output (used to scale to [-1.0, 1.0])

185 uint16_t samples_per_frame; ///< number of samples to output

186 uint16_t log2_frame_size;

187 int8_t lfe_channel; ///< lfe channel index

188 uint8_t max_num_subframes;

189 uint8_t subframe_len_bits; ///< number of bits used for the subframe length

190 uint8_t max_subframe_len_bit; ///< flag indicating that the subframe is of maximum size when the first subframe length bit is 1

191 uint16_t min_samples_per_subframe;

192 int8_t num_sfb[WMAPRO_BLOCK_SIZES]; ///< scale factor bands per block size

193 int16_t sfb_offsets[WMAPRO_BLOCK_SIZES][MAX_BANDS]; ///< scale factor band offsets (multiples of 4)

194 int8_t sf_offsets[WMAPRO_BLOCK_SIZES][WMAPRO_BLOCK_SIZES][MAX_BANDS]; ///< scale factor resample matrix

195 int16_t subwoofer_cutoffs[WMAPRO_BLOCK_SIZES]; ///< subwoofer cutoff values

196

197 /* packet decode state */

198 GetBitContext pgb; ///< bitstream reader context for the packet

199 int next_packet_start; ///< start offset of the next wma packet in the demuxer packet

200 uint8_t packet_offset; ///< frame offset in the packet

201 uint8_t packet_sequence_number; ///< current packet number

202 int num_saved_bits; ///< saved number of bits

203 int frame_offset; ///< frame offset in the bit reservoir

204 int subframe_offset; ///< subframe offset in the bit reservoir

205 uint8_t packet_loss; ///< set in case of bitstream error

206 uint8_t packet_done; ///< set when a packet is fully decoded

207

208 /* frame decode state */

209 uint32_t frame_num; ///< current frame number (not used for decoding)

210 GetBitContext gb; ///< bitstream reader context

211 int buf_bit_size; ///< buffer size in bits

212 uint8_t drc_gain; ///< gain for the DRC tool

213 int8_t skip_frame; ///< skip output step

214 int8_t parsed_all_subframes; ///< all subframes decoded?

215

216 /* subframe/block decode state */

217 int16_t subframe_len; ///< current subframe length

218 int8_t channels_for_cur_subframe; ///< number of channels that contain the subframe

219 int8_t channel_indexes_for_cur_subframe[WMAPRO_MAX_CHANNELS];

220 int8_t num_bands; ///< number of scale factor bands

221 int8_t transmit_num_vec_coeffs; ///< number of vector coded coefficients is part of the bitstream

222 int16_t* cur_sfb_offsets; ///< sfb offsets for the current block

223 uint8_t table_idx; ///< index for the num_sfb, sfb_offsets, sf_offsets and subwoofer_cutoffs tables

224 int8_t esc_len; ///< length of escaped coefficients

225

226 uint8_t num_chgroups; ///< number of channel groups

227 WMAProChannelGrp chgroup[WMAPRO_MAX_CHANNELS]; ///< channel group information

228

229 WMAProChannelCtx channel[WMAPRO_MAX_CHANNELS]; ///< per channel data

230 } WMAProDecodeCtx;

231

232

233 /**

234 *@brief helper function to print the most important members of the context

235 *@param s context

236 */

237 static av_cold void dump_context(WMAProDecodeCtx *s)

238 {

239 #define PRINT(a, b) av_log(s->avctx, AV_LOG_DEBUG, " %s = %d\n", a, b);

240 #define PRINT_HEX(a, b) av_log(s->avctx, AV_LOG_DEBUG, " %s = %x\n", a, b);

241

242 PRINT("ed sample bit depth", s->bits_per_sample);

243 PRINT_HEX("ed decode flags", s->decode_flags);

244 PRINT("samples per frame", s->samples_per_frame);

245 PRINT("log2 frame size", s->log2_frame_size);

246 PRINT("max num subframes", s->max_num_subframes);

247 PRINT("len prefix", s->len_prefix);

248 PRINT("num channels", s->avctx->channels);

249 }

250

251 /**

252 *@brief Uninitialize the decoder and free all resources.

253 *@param avctx codec context

254 *@return 0 on success, < 0 otherwise

255 */

256 static av_cold int decode_end(AVCodecContext *avctx)

257 {

258 WMAProDecodeCtx *s = avctx->priv_data;

259 int i;

260

261 for (i = 0; i < WMAPRO_BLOCK_SIZES; i++)

262 ff_mdct_end(&s->mdct_ctx[i]);

263

264 return 0;

265 }

266

267 /**

268 *@brief Initialize the decoder.

269 *@param avctx codec context

270 *@return 0 on success, -1 otherwise

271 */

272 static av_cold int decode_init(AVCodecContext *avctx)

273 {

274 WMAProDecodeCtx *s = avctx->priv_data;

275 uint8_t *edata_ptr = avctx->extradata;

276 unsigned int channel_mask;

277 int i, bits;

278 int log2_max_num_subframes;

279 int num_possible_block_sizes;

280

281 if (!avctx->block_align) {

282 av_log(avctx, AV_LOG_ERROR, "block_align is not set\n");

283 return AVERROR(EINVAL);

284 }

285

286 s->avctx = avctx;

287 avpriv_float_dsp_init(&s->fdsp, avctx->flags & CODEC_FLAG_BITEXACT);

288

289 init_put_bits(&s->pb, s->frame_data, MAX_FRAMESIZE);

290

291 avctx->sample_fmt = AV_SAMPLE_FMT_FLTP;

292

293 if (avctx->extradata_size >= 18) {

294 s->decode_flags = AV_RL16(edata_ptr+14);

295 channel_mask = AV_RL32(edata_ptr+2);

296 s->bits_per_sample = AV_RL16(edata_ptr);

297 /** dump the extradata */

298 for (i = 0; i < avctx->extradata_size; i++)

299 av_dlog(avctx, "[%x] ", avctx->extradata[i]);

300 av_dlog(avctx, "\n");

301

302 } else {

303 avpriv_request_sample(avctx, "Unknown extradata size");

304 return AVERROR_PATCHWELCOME;

305 }

306

307 /** generic init */

308 s->log2_frame_size = av_log2(avctx->block_align) + 4;

309 if (s->log2_frame_size > 25) {

310 avpriv_request_sample(avctx, "Large block align");

311 return AVERROR_PATCHWELCOME;

312 }

313

314 /** frame info */

315 s->skip_frame = 1; /* skip first frame */

316 s->packet_loss = 1;

317 s->len_prefix = (s->decode_flags & 0x40);

318

319 /** get frame len */

320 bits = ff_wma_get_frame_len_bits(avctx->sample_rate, 3, s->decode_flags);

321 if (bits > WMAPRO_BLOCK_MAX_BITS) {

322 avpriv_request_sample(avctx, "14-bit block sizes");

323 return AVERROR_PATCHWELCOME;

324 }

325 s->samples_per_frame = 1 << bits;

326

327 /** subframe info */

328 log2_max_num_subframes = ((s->decode_flags & 0x38) >> 3);

329 s->max_num_subframes = 1 << log2_max_num_subframes;

330 if (s->max_num_subframes == 16 || s->max_num_subframes == 4)

331 s->max_subframe_len_bit = 1;

332 s->subframe_len_bits = av_log2(log2_max_num_subframes) + 1;

333

334 num_possible_block_sizes = log2_max_num_subframes + 1;

335 s->min_samples_per_subframe = s->samples_per_frame / s->max_num_subframes;

336 s->dynamic_range_compression = (s->decode_flags & 0x80);

337

338 if (s->max_num_subframes > MAX_SUBFRAMES) {

339 av_log(avctx, AV_LOG_ERROR, "invalid number of subframes %i\n",

340 s->max_num_subframes);

341 return AVERROR_INVALIDDATA;

342 }

343

344 if (s->min_samples_per_subframe < WMAPRO_BLOCK_MIN_SIZE) {

345 av_log(avctx, AV_LOG_ERROR, "min_samples_per_subframe of %d too small\n",

346 s->min_samples_per_subframe);

347 return AVERROR_INVALIDDATA;

348 }

349

350 if (s->avctx->sample_rate <= 0) {

351 av_log(avctx, AV_LOG_ERROR, "invalid sample rate\n");

352 return AVERROR_INVALIDDATA;

353 }

354

355 if (avctx->channels < 0) {

356 av_log(avctx, AV_LOG_ERROR, "invalid number of channels %d\n",

357 avctx->channels);

358 return AVERROR_INVALIDDATA;

359 } else if (avctx->channels > WMAPRO_MAX_CHANNELS) {

360 avpriv_request_sample(avctx,

361 "More than %d channels", WMAPRO_MAX_CHANNELS);

362 return AVERROR_PATCHWELCOME;

363 }

364

365 /** init previous block len */

366 for (i = 0; i < avctx->channels; i++)

367 s->channel[i].prev_block_len = s->samples_per_frame;

368

369 /** extract lfe channel position */

370 s->lfe_channel = -1;

371

372 if (channel_mask & 8) {

373 unsigned int mask;

374 for (mask = 1; mask < 16; mask <<= 1) {

375 if (channel_mask & mask)

376 ++s->lfe_channel;

377 }

378 }

379

380 INIT_VLC_STATIC(&sf_vlc, SCALEVLCBITS, HUFF_SCALE_SIZE,

381 scale_huffbits, 1, 1,

382 scale_huffcodes, 2, 2, 616);

383

384 INIT_VLC_STATIC(&sf_rl_vlc, VLCBITS, HUFF_SCALE_RL_SIZE,

385 scale_rl_huffbits, 1, 1,

386 scale_rl_huffcodes, 4, 4, 1406);

387

388 INIT_VLC_STATIC(&coef_vlc[0], VLCBITS, HUFF_COEF0_SIZE,

389 coef0_huffbits, 1, 1,

390 coef0_huffcodes, 4, 4, 2108);

391

392 INIT_VLC_STATIC(&coef_vlc[1], VLCBITS, HUFF_COEF1_SIZE,

393 coef1_huffbits, 1, 1,

394 coef1_huffcodes, 4, 4, 3912);

395

396 INIT_VLC_STATIC(&vec4_vlc, VLCBITS, HUFF_VEC4_SIZE,

397 vec4_huffbits, 1, 1,

398 vec4_huffcodes, 2, 2, 604);

399

400 INIT_VLC_STATIC(&vec2_vlc, VLCBITS, HUFF_VEC2_SIZE,

401 vec2_huffbits, 1, 1,

402 vec2_huffcodes, 2, 2, 562);

403

404 INIT_VLC_STATIC(&vec1_vlc, VLCBITS, HUFF_VEC1_SIZE,

405 vec1_huffbits, 1, 1,

406 vec1_huffcodes, 2, 2, 562);

407

408 /** calculate number of scale factor bands and their offsets

409 for every possible block size */

410 for (i = 0; i < num_possible_block_sizes; i++) {

411 int subframe_len = s->samples_per_frame >> i;

412 int x;

413 int band = 1;

414

415 s->sfb_offsets[i][0] = 0;

416

417 for (x = 0; x < MAX_BANDS-1 && s->sfb_offsets[i][band - 1] < subframe_len; x++) {

418 int offset = (subframe_len * 2 * critical_freq[x])

419 / s->avctx->sample_rate + 2;

420 offset &= ~3;

421 if (offset > s->sfb_offsets[i][band - 1])

422 s->sfb_offsets[i][band++] = offset;

423 }

424 s->sfb_offsets[i][band - 1] = subframe_len;

425 s->num_sfb[i] = band - 1;

426 if (s->num_sfb[i] <= 0) {

427 av_log(avctx, AV_LOG_ERROR, "num_sfb invalid\n");

428 return AVERROR_INVALIDDATA;

429 }

430 }

431

432

433 /** Scale factors can be shared between blocks of different size

434 as every block has a different scale factor band layout.

435 The matrix sf_offsets is needed to find the correct scale factor.

436 */

437

438 for (i = 0; i < num_possible_block_sizes; i++) {

439 int b;

440 for (b = 0; b < s->num_sfb[i]; b++) {

441 int x;

442 int offset = ((s->sfb_offsets[i][b]

443 + s->sfb_offsets[i][b + 1] - 1) << i) >> 1;

444 for (x = 0; x < num_possible_block_sizes; x++) {

445 int v = 0;

446 while (s->sfb_offsets[x][v + 1] << x < offset) {

447 v++;

448 av_assert0(v < MAX_BANDS);

449 }

450 s->sf_offsets[i][x][b] = v;

451 }

452 }

453 }

454

455 /** init MDCT, FIXME: only init needed sizes */

456 for (i = 0; i < WMAPRO_BLOCK_SIZES; i++)

457 ff_mdct_init(&s->mdct_ctx[i], WMAPRO_BLOCK_MIN_BITS+1+i, 1,

458 1.0 / (1 << (WMAPRO_BLOCK_MIN_BITS + i - 1))

459 / (1 << (s->bits_per_sample - 1)));

460

461 /** init MDCT windows: simple sine window */

462 for (i = 0; i < WMAPRO_BLOCK_SIZES; i++) {

463 const int win_idx = WMAPRO_BLOCK_MAX_BITS - i;

464 ff_init_ff_sine_windows(win_idx);

465 s->windows[WMAPRO_BLOCK_SIZES - i - 1] = ff_sine_windows[win_idx];

466 }

467

468 /** calculate subwoofer cutoff values */

469 for (i = 0; i < num_possible_block_sizes; i++) {

470 int block_size = s->samples_per_frame >> i;

471 int cutoff = (440*block_size + 3 * (s->avctx->sample_rate >> 1) - 1)

472 / s->avctx->sample_rate;

473 s->subwoofer_cutoffs[i] = av_clip(cutoff, 4, block_size);

474 }

475

476 /** calculate sine values for the decorrelation matrix */

477 for (i = 0; i < 33; i++)

478 sin64[i] = sin(i*M_PI / 64.0);

479

480 if (avctx->debug & FF_DEBUG_BITSTREAM)

481 dump_context(s);

482

483 avctx->channel_layout = channel_mask;

484

485 return 0;

486 }

487

488 /**

489 *@brief Decode the subframe length.

490 *@param s context

491 *@param offset sample offset in the frame

492 *@return decoded subframe length on success, < 0 in case of an error

493 */

494 static int decode_subframe_length(WMAProDecodeCtx *s, int offset)

495 {

496 int frame_len_shift = 0;

497 int subframe_len;

498

499 /** no need to read from the bitstream when only one length is possible */

500 if (offset == s->samples_per_frame - s->min_samples_per_subframe)

501 return s->min_samples_per_subframe;

502

503 if (get_bits_left(&s->gb) < 1)

504 return AVERROR_INVALIDDATA;

505

506 /** 1 bit indicates if the subframe is of maximum length */

507 if (s->max_subframe_len_bit) {

508 if (get_bits1(&s->gb))

509 frame_len_shift = 1 + get_bits(&s->gb, s->subframe_len_bits-1);

510 } else

511 frame_len_shift = get_bits(&s->gb, s->subframe_len_bits);

512

513 subframe_len = s->samples_per_frame >> frame_len_shift;

514

515 /** sanity check the length */

516 if (subframe_len < s->min_samples_per_subframe ||

517 subframe_len > s->samples_per_frame) {

518 av_log(s->avctx, AV_LOG_ERROR, "broken frame: subframe_len %i\n",

519 subframe_len);

520 return AVERROR_INVALIDDATA;

521 }

522 return subframe_len;

523 }

524

525 /**

526 *@brief Decode how the data in the frame is split into subframes.

527 * Every WMA frame contains the encoded data for a fixed number of

528 * samples per channel. The data for every channel might be split

529 * into several subframes. This function will reconstruct the list of

530 * subframes for every channel.

531 *

532 * If the subframes are not evenly split, the algorithm estimates the

533 * channels with the lowest number of total samples.

534 * Afterwards, for each of these channels a bit is read from the

535 * bitstream that indicates if the channel contains a subframe with the

536 * next subframe size that is going to be read from the bitstream or not.

537 * If a channel contains such a subframe, the subframe size gets added to

538 * the channel's subframe list.

539 * The algorithm repeats these steps until the frame is properly divided

540 * between the individual channels.

541 *

542 *@param s context

543 *@return 0 on success, < 0 in case of an error

544 */

545 static int decode_tilehdr(WMAProDecodeCtx *s)

546 {

547 uint16_t num_samples[WMAPRO_MAX_CHANNELS] = { 0 };/**< sum of samples for all currently known subframes of a channel */

548 uint8_t contains_subframe[WMAPRO_MAX_CHANNELS]; /**< flag indicating if a channel contains the current subframe */

549 int channels_for_cur_subframe = s->avctx->channels; /**< number of channels that contain the current subframe */

550 int fixed_channel_layout = 0; /**< flag indicating that all channels use the same subframe offsets and sizes */

551 int min_channel_len = 0; /**< smallest sum of samples (channels with this length will be processed first) */

552 int c;

553

554 /* Should never consume more than 3073 bits (256 iterations for the

555 * while loop when always the minimum amount of 128 samples is subtracted

556 * from missing samples in the 8 channel case).

557 * 1 + BLOCK_MAX_SIZE * MAX_CHANNELS / BLOCK_MIN_SIZE * (MAX_CHANNELS + 4)

558 */

559

560 /** reset tiling information */

561 for (c = 0; c < s->avctx->channels; c++)

562 s->channel[c].num_subframes = 0;

563

564 if (s->max_num_subframes == 1 || get_bits1(&s->gb))

565 fixed_channel_layout = 1;

566

567 /** loop until the frame data is split between the subframes */

568 do {

569 int subframe_len;

570

571 /** check which channels contain the subframe */

572 for (c = 0; c < s->avctx->channels; c++) {

573 if (num_samples[c] == min_channel_len) {

574 if (fixed_channel_layout || channels_for_cur_subframe == 1 ||

575 (min_channel_len == s->samples_per_frame - s->min_samples_per_subframe))

576 contains_subframe[c] = 1;

577 else

578 contains_subframe[c] = get_bits1(&s->gb);

579 } else

580 contains_subframe[c] = 0;

581 }

582

583 /** get subframe length, subframe_len == 0 is not allowed */

584 if ((subframe_len = decode_subframe_length(s, min_channel_len)) <= 0)

585 return AVERROR_INVALIDDATA;

586

587 /** add subframes to the individual channels and find new min_channel_len */

588 min_channel_len += subframe_len;

589 for (c = 0; c < s->avctx->channels; c++) {

590 WMAProChannelCtx* chan = &s->channel[c];

591

592 if (contains_subframe[c]) {

593 if (chan->num_subframes >= MAX_SUBFRAMES) {

594 av_log(s->avctx, AV_LOG_ERROR,

595 "broken frame: num subframes > 31\n");

596 return AVERROR_INVALIDDATA;

597 }

598 chan->subframe_len[chan->num_subframes] = subframe_len;

599 num_samples[c] += subframe_len;

600 ++chan->num_subframes;

601 if (num_samples[c] > s->samples_per_frame) {

602 av_log(s->avctx, AV_LOG_ERROR, "broken frame: "

603 "channel len > samples_per_frame\n");

604 return AVERROR_INVALIDDATA;

605 }

606 } else if (num_samples[c] <= min_channel_len) {

607 if (num_samples[c] < min_channel_len) {

608 channels_for_cur_subframe = 0;

609 min_channel_len = num_samples[c];

610 }

611 ++channels_for_cur_subframe;

612 }

613 }

614 } while (min_channel_len < s->samples_per_frame);

615

616 for (c = 0; c < s->avctx->channels; c++) {

617 int i;

618 int offset = 0;

619 for (i = 0; i < s->channel[c].num_subframes; i++) {

620 av_dlog(s->avctx, "frame[%i] channel[%i] subframe[%i]"

621 " len %i\n", s->frame_num, c, i,

622 s->channel[c].subframe_len[i]);

623 s->channel[c].subframe_offset[i] = offset;

624 offset += s->channel[c].subframe_len[i];

625 }

626 }

627

628 return 0;

629 }

630

631 /**

632 *@brief Calculate a decorrelation matrix from the bitstream parameters.

633 *@param s codec context

634 *@param chgroup channel group for which the matrix needs to be calculated

635 */

636 static void decode_decorrelation_matrix(WMAProDecodeCtx *s,

637 WMAProChannelGrp *chgroup)

638 {

639 int i;

640 int offset = 0;

641 int8_t rotation_offset[WMAPRO_MAX_CHANNELS * WMAPRO_MAX_CHANNELS];

642 memset(chgroup->decorrelation_matrix, 0, s->avctx->channels *

643 s->avctx->channels * sizeof(*chgroup->decorrelation_matrix));

644

645 for (i = 0; i < chgroup->num_channels * (chgroup->num_channels - 1) >> 1; i++)

646 rotation_offset[i] = get_bits(&s->gb, 6);

647

648 for (i = 0; i < chgroup->num_channels; i++)

649 chgroup->decorrelation_matrix[chgroup->num_channels * i + i] =

650 get_bits1(&s->gb) ? 1.0 : -1.0;

651

652 for (i = 1; i < chgroup->num_channels; i++) {

653 int x;

654 for (x = 0; x < i; x++) {

655 int y;

656 for (y = 0; y < i + 1; y++) {

657 float v1 = chgroup->decorrelation_matrix[x * chgroup->num_channels + y];

658 float v2 = chgroup->decorrelation_matrix[i * chgroup->num_channels + y];

659 int n = rotation_offset[offset + x];

660 float sinv;

661 float cosv;

662

663 if (n < 32) {

664 sinv = sin64[n];

665 cosv = sin64[32 - n];

666 } else {

667 sinv = sin64[64 - n];

668 cosv = -sin64[n - 32];

669 }

670

671 chgroup->decorrelation_matrix[y + x * chgroup->num_channels] =

672 (v1 * sinv) - (v2 * cosv);

673 chgroup->decorrelation_matrix[y + i * chgroup->num_channels] =

674 (v1 * cosv) + (v2 * sinv);

675 }

676 }

677 offset += i;

678 }

679 }

680

681 /**

682 *@brief Decode channel transformation parameters

683 *@param s codec context

684 *@return >= 0 in case of success, < 0 in case of bitstream errors

685 */

686 static int decode_channel_transform(WMAProDecodeCtx* s)

687 {

688 int i;

689 /* should never consume more than 1921 bits for the 8 channel case

690 * 1 + MAX_CHANNELS * (MAX_CHANNELS + 2 + 3 * MAX_CHANNELS * MAX_CHANNELS

691 * + MAX_CHANNELS + MAX_BANDS + 1)

692 */

693

694 /** in the one channel case channel transforms are pointless */

695 s->num_chgroups = 0;

696 if (s->avctx->channels > 1) {

697 int remaining_channels = s->channels_for_cur_subframe;

698

699 if (get_bits1(&s->gb)) {

700 avpriv_request_sample(s->avctx,

701 "Channel transform bit");

702 return AVERROR_PATCHWELCOME;

703 }

704

705 for (s->num_chgroups = 0; remaining_channels &&

706 s->num_chgroups < s->channels_for_cur_subframe; s->num_chgroups++) {

707 WMAProChannelGrp* chgroup = &s->chgroup[s->num_chgroups];

708 float** channel_data = chgroup->channel_data;

709 chgroup->num_channels = 0;

710 chgroup->transform = 0;

711

712 /** decode channel mask */

713 if (remaining_channels > 2) {

714 for (i = 0; i < s->channels_for_cur_subframe; i++) {

715 int channel_idx = s->channel_indexes_for_cur_subframe[i];

716 if (!s->channel[channel_idx].grouped

717 && get_bits1(&s->gb)) {

718 ++chgroup->num_channels;

719 s->channel[channel_idx].grouped = 1;

720 *channel_data++ = s->channel[channel_idx].coeffs;

721 }

722 }

723 } else {

724 chgroup->num_channels = remaining_channels;

725 for (i = 0; i < s->channels_for_cur_subframe; i++) {

726 int channel_idx = s->channel_indexes_for_cur_subframe[i];

727 if (!s->channel[channel_idx].grouped)

728 *channel_data++ = s->channel[channel_idx].coeffs;

729 s->channel[channel_idx].grouped = 1;

730 }

731 }

732

733 /** decode transform type */

734 if (chgroup->num_channels == 2) {

735 if (get_bits1(&s->gb)) {

736 if (get_bits1(&s->gb)) {

737 avpriv_request_sample(s->avctx,

738 "Unknown channel transform type");

739 return AVERROR_PATCHWELCOME;

740 }

741 } else {

742 chgroup->transform = 1;

743 if (s->avctx->channels == 2) {

744 chgroup->decorrelation_matrix[0] = 1.0;

745 chgroup->decorrelation_matrix[1] = -1.0;

746 chgroup->decorrelation_matrix[2] = 1.0;

747 chgroup->decorrelation_matrix[3] = 1.0;

748 } else {

749 /** cos(pi/4) */

750 chgroup->decorrelation_matrix[0] = 0.70703125;

751 chgroup->decorrelation_matrix[1] = -0.70703125;

752 chgroup->decorrelation_matrix[2] = 0.70703125;

753 chgroup->decorrelation_matrix[3] = 0.70703125;

754 }

755 }

756 } else if (chgroup->num_channels > 2) {

757 if (get_bits1(&s->gb)) {

758 chgroup->transform = 1;

759 if (get_bits1(&s->gb)) {

760 decode_decorrelation_matrix(s, chgroup);

761 } else {

762 /** FIXME: more than 6 coupled channels not supported */

763 if (chgroup->num_channels > 6) {

764 avpriv_request_sample(s->avctx,

765 "Coupled channels > 6");

766 } else {

767 memcpy(chgroup->decorrelation_matrix,

768 default_decorrelation[chgroup->num_channels],

769 chgroup->num_channels * chgroup->num_channels *

770 sizeof(*chgroup->decorrelation_matrix));

771 }

772 }

773 }

774 }

775

776 /** decode transform on / off */

777 if (chgroup->transform) {

778 if (!get_bits1(&s->gb)) {

779 int i;

780 /** transform can be enabled for individual bands */

781 for (i = 0; i < s->num_bands; i++) {

782 chgroup->transform_band[i] = get_bits1(&s->gb);

783 }

784 } else {

785 memset(chgroup->transform_band, 1, s->num_bands);

786 }

787 }

788 remaining_channels -= chgroup->num_channels;

789 }

790 }

791 return 0;

792 }

793

794 /**

795 *@brief Extract the coefficients from the bitstream.

796 *@param s codec context

797 *@param c current channel number

798 *@return 0 on success, < 0 in case of bitstream errors

799 */

800 static int decode_coeffs(WMAProDecodeCtx *s, int c)

801 {

802 /* Integers 0..15 as single-precision floats. The table saves a

803 costly int to float conversion, and storing the values as

804 integers allows fast sign-flipping. */

805 static const uint32_t fval_tab[16] = {

806 0x00000000, 0x3f800000, 0x40000000, 0x40400000,

807 0x40800000, 0x40a00000, 0x40c00000, 0x40e00000,

808 0x41000000, 0x41100000, 0x41200000, 0x41300000,

809 0x41400000, 0x41500000, 0x41600000, 0x41700000,

810 };

811 int vlctable;

812 VLC* vlc;

813 WMAProChannelCtx* ci = &s->channel[c];

814 int rl_mode = 0;

815 int cur_coeff = 0;

816 int num_zeros = 0;

817 const uint16_t* run;

818 const float* level;

819

820 av_dlog(s->avctx, "decode coefficients for channel %i\n", c);

821

822 vlctable = get_bits1(&s->gb);

823 vlc = &coef_vlc[vlctable];

824

825 if (vlctable) {

826 run = coef1_run;

827 level = coef1_level;

828 } else {

829 run = coef0_run;

830 level = coef0_level;

831 }

832

833 /** decode vector coefficients (consumes up to 167 bits per iteration for

834 4 vector coded large values) */

835 while ((s->transmit_num_vec_coeffs || !rl_mode) &&

836 (cur_coeff + 3 < ci->num_vec_coeffs)) {

837 uint32_t vals[4];

838 int i;

839 unsigned int idx;

840

841 idx = get_vlc2(&s->gb, vec4_vlc.table, VLCBITS, VEC4MAXDEPTH);

842

843 if (idx == HUFF_VEC4_SIZE - 1) {

844 for (i = 0; i < 4; i += 2) {

845 idx = get_vlc2(&s->gb, vec2_vlc.table, VLCBITS, VEC2MAXDEPTH);

846 if (idx == HUFF_VEC2_SIZE - 1) {

847 uint32_t v0, v1;

848 v0 = get_vlc2(&s->gb, vec1_vlc.table, VLCBITS, VEC1MAXDEPTH);

849 if (v0 == HUFF_VEC1_SIZE - 1)

850 v0 += ff_wma_get_large_val(&s->gb);

851 v1 = get_vlc2(&s->gb, vec1_vlc.table, VLCBITS, VEC1MAXDEPTH);

852 if (v1 == HUFF_VEC1_SIZE - 1)

853 v1 += ff_wma_get_large_val(&s->gb);

854 vals[i ] = av_float2int(v0);

855 vals[i+1] = av_float2int(v1);

856 } else {

857 vals[i] = fval_tab[symbol_to_vec2[idx] >> 4 ];

858 vals[i+1] = fval_tab[symbol_to_vec2[idx] & 0xF];

859 }

860 }

861 } else {

862 vals[0] = fval_tab[ symbol_to_vec4[idx] >> 12 ];

863 vals[1] = fval_tab[(symbol_to_vec4[idx] >> 8) & 0xF];

864 vals[2] = fval_tab[(symbol_to_vec4[idx] >> 4) & 0xF];

865 vals[3] = fval_tab[ symbol_to_vec4[idx] & 0xF];

866 }

867

868 /** decode sign */

869 for (i = 0; i < 4; i++) {

870 if (vals[i]) {

871 uint32_t sign = get_bits1(&s->gb) - 1;

872 AV_WN32A(&ci->coeffs[cur_coeff], vals[i] ^ sign << 31);

873 num_zeros = 0;

874 } else {

875 ci->coeffs[cur_coeff] = 0;

876 /** switch to run level mode when subframe_len / 128 zeros

877 were found in a row */

878 rl_mode |= (++num_zeros > s->subframe_len >> 8);

879 }

880 ++cur_coeff;

881 }

882 }

883

884 /** decode run level coded coefficients */

885 if (cur_coeff < s->subframe_len) {

886 memset(&ci->coeffs[cur_coeff], 0,

887 sizeof(*ci->coeffs) * (s->subframe_len - cur_coeff));

888 if (ff_wma_run_level_decode(s->avctx, &s->gb, vlc,

889 level, run, 1, ci->coeffs,

890 cur_coeff, s->subframe_len,

891 s->subframe_len, s->esc_len, 0))

892 return AVERROR_INVALIDDATA;

893 }

894

895 return 0;

896 }

897

898 /**

899 *@brief Extract scale factors from the bitstream.

900 *@param s codec context

901 *@return 0 on success, < 0 in case of bitstream errors

902 */

903 static int decode_scale_factors(WMAProDecodeCtx* s)

904 {

905 int i;

906

907 /** should never consume more than 5344 bits

908 * MAX_CHANNELS * (1 + MAX_BANDS * 23)

909 */

910

911 for (i = 0; i < s->channels_for_cur_subframe; i++) {

912 int c = s->channel_indexes_for_cur_subframe[i];

913 int* sf;

914 int* sf_end;

915 s->channel[c].scale_factors = s->channel[c].saved_scale_factors[!s->channel[c].scale_factor_idx];

916 sf_end = s->channel[c].scale_factors + s->num_bands;

917

918 /** resample scale factors for the new block size

919 * as the scale factors might need to be resampled several times

920 * before some new values are transmitted, a backup of the last

921 * transmitted scale factors is kept in saved_scale_factors

922 */

923 if (s->channel[c].reuse_sf) {

924 const int8_t* sf_offsets = s->sf_offsets[s->table_idx][s->channel[c].table_idx];

925 int b;

926 for (b = 0; b < s->num_bands; b++)

927 s->channel[c].scale_factors[b] =

928 s->channel[c].saved_scale_factors[s->channel[c].scale_factor_idx][*sf_offsets++];

929 }

930

931 if (!s->channel[c].cur_subframe || get_bits1(&s->gb)) {

932

933 if (!s->channel[c].reuse_sf) {

934 int val;

935 /** decode DPCM coded scale factors */

936 s->channel[c].scale_factor_step = get_bits(&s->gb, 2) + 1;

937 val = 45 / s->channel[c].scale_factor_step;

938 for (sf = s->channel[c].scale_factors; sf < sf_end; sf++) {

939 val += get_vlc2(&s->gb, sf_vlc.table, SCALEVLCBITS, SCALEMAXDEPTH) - 60;

940 *sf = val;

941 }

942 } else {

943 int i;

944 /** run level decode differences to the resampled factors */

945 for (i = 0; i < s->num_bands; i++) {

946 int idx;

947 int skip;

948 int val;

949 int sign;

950

951 idx = get_vlc2(&s->gb, sf_rl_vlc.table, VLCBITS, SCALERLMAXDEPTH);

952

953 if (!idx) {

954 uint32_t code = get_bits(&s->gb, 14);

955 val = code >> 6;

956 sign = (code & 1) - 1;

957 skip = (code & 0x3f) >> 1;

958 } else if (idx == 1) {

959 break;

960 } else {

961 skip = scale_rl_run[idx];

962 val = scale_rl_level[idx];

963 sign = get_bits1(&s->gb)-1;

964 }

965

966 i += skip;

967 if (i >= s->num_bands) {

968 av_log(s->avctx, AV_LOG_ERROR,

969 "invalid scale factor coding\n");

970 return AVERROR_INVALIDDATA;

971 }

972 s->channel[c].scale_factors[i] += (val ^ sign) - sign;

973 }

974 }

975 /** swap buffers */

976 s->channel[c].scale_factor_idx = !s->channel[c].scale_factor_idx;

977 s->channel[c].table_idx = s->table_idx;

978 s->channel[c].reuse_sf = 1;

979 }

980

981 /** calculate new scale factor maximum */

982 s->channel[c].max_scale_factor = s->channel[c].scale_factors[0];

983 for (sf = s->channel[c].scale_factors + 1; sf < sf_end; sf++) {

984 s->channel[c].max_scale_factor =

985 FFMAX(s->channel[c].max_scale_factor, *sf);

986 }

987

988 }

989 return 0;

990 }

991

992 /**

993 *@brief Reconstruct the individual channel data.

994 *@param s codec context

995 */

996 static void inverse_channel_transform(WMAProDecodeCtx *s)

997 {

998 int i;

999

1000 for (i = 0; i < s->num_chgroups; i++) {

1001 if (s->chgroup[i].transform) {

1002 float data[WMAPRO_MAX_CHANNELS];

1003 const int num_channels = s->chgroup[i].num_channels;

1004 float** ch_data = s->chgroup[i].channel_data;

1005 float** ch_end = ch_data + num_channels;

1006 const int8_t* tb = s->chgroup[i].transform_band;

1007 int16_t* sfb;

1008

1009 /** multichannel decorrelation */

1010 for (sfb = s->cur_sfb_offsets;

1011 sfb < s->cur_sfb_offsets + s->num_bands; sfb++) {

1012 int y;

1013 if (*tb++ == 1) {

1014 /** multiply values with the decorrelation_matrix */

1015 for (y = sfb[0]; y < FFMIN(sfb[1], s->subframe_len); y++) {

1016 const float* mat = s->chgroup[i].decorrelation_matrix;

1017 const float* data_end = data + num_channels;

1018 float* data_ptr = data;

1019 float** ch;

1020

1021 for (ch = ch_data; ch < ch_end; ch++)

1022 *data_ptr++ = (*ch)[y];

1023

1024 for (ch = ch_data; ch < ch_end; ch++) {

1025 float sum = 0;

1026 data_ptr = data;

1027 while (data_ptr < data_end)

1028 sum += *data_ptr++ * *mat++;

1029

1030 (*ch)[y] = sum;

1031 }

1032 }

1033 } else if (s->avctx->channels == 2) {

1034 int len = FFMIN(sfb[1], s->subframe_len) - sfb[0];

1035 s->fdsp.vector_fmul_scalar(ch_data[0] + sfb[0],

1036 ch_data[0] + sfb[0],

1037 181.0 / 128, len);

1038 s->fdsp.vector_fmul_scalar(ch_data[1] + sfb[0],

1039 ch_data[1] + sfb[0],

1040 181.0 / 128, len);

1041 }

1042 }

1043 }

1044 }

1045 }

1046

1047 /**

1048 *@brief Apply sine window and reconstruct the output buffer.

1049 *@param s codec context

1050 */

1051 static void wmapro_window(WMAProDecodeCtx *s)

1052 {

1053 int i;

1054 for (i = 0; i < s->channels_for_cur_subframe; i++) {

1055 int c = s->channel_indexes_for_cur_subframe[i];

1056 float* window;

1057 int winlen = s->channel[c].prev_block_len;

1058 float* start = s->channel[c].coeffs - (winlen >> 1);

1059

1060 if (s->subframe_len < winlen) {

1061 start += (winlen - s->subframe_len) >> 1;

1062 winlen = s->subframe_len;

1063 }

1064

1065 window = s->windows[av_log2(winlen) - WMAPRO_BLOCK_MIN_BITS];

1066

1067 winlen >>= 1;

1068

1069 s->fdsp.vector_fmul_window(start, start, start + winlen,

1070 window, winlen);

1071

1072 s->channel[c].prev_block_len = s->subframe_len;

1073 }

1074 }

1075

1076 /**

1077 *@brief Decode a single subframe (block).

1078 *@param s codec context

1079 *@return 0 on success, < 0 when decoding failed

1080 */

1081 static int decode_subframe(WMAProDecodeCtx *s)

1082 {

1083 int offset = s->samples_per_frame;

1084 int subframe_len = s->samples_per_frame;

1085 int i;

1086 int total_samples = s->samples_per_frame * s->avctx->channels;

1087 int transmit_coeffs = 0;

1088 int cur_subwoofer_cutoff;

1089

1090 s->subframe_offset = get_bits_count(&s->gb);

1091

1092 /** reset channel context and find the next block offset and size

1093 == the next block of the channel with the smallest number of

1094 decoded samples

1095 */

1096 for (i = 0; i < s->avctx->channels; i++) {

1097 s->channel[i].grouped = 0;

1098 if (offset > s->channel[i].decoded_samples) {

1099 offset = s->channel[i].decoded_samples;

1100 subframe_len =

1101 s->channel[i].subframe_len[s->channel[i].cur_subframe];

1102 }

1103 }

1104

1105 av_dlog(s->avctx,

1106 "processing subframe with offset %i len %i\n", offset, subframe_len);

1107

1108 /** get a list of all channels that contain the estimated block */

1109 s->channels_for_cur_subframe = 0;

1110 for (i = 0; i < s->avctx->channels; i++) {

1111 const int cur_subframe = s->channel[i].cur_subframe;

1112 /** subtract already processed samples */

1113 total_samples -= s->channel[i].decoded_samples;

1114

1115 /** and count if there are multiple subframes that match our profile */

1116 if (offset == s->channel[i].decoded_samples &&

1117 subframe_len == s->channel[i].subframe_len[cur_subframe]) {

1118 total_samples -= s->channel[i].subframe_len[cur_subframe];

1119 s->channel[i].decoded_samples +=

1120 s->channel[i].subframe_len[cur_subframe];

1121 s->channel_indexes_for_cur_subframe[s->channels_for_cur_subframe] = i;

1122 ++s->channels_for_cur_subframe;

1123 }

1124 }

1125

1126 /** check if the frame will be complete after processing the

1127 estimated block */

1128 if (!total_samples)

1129 s->parsed_all_subframes = 1;

1130

1131

1132 av_dlog(s->avctx, "subframe is part of %i channels\n",

1133 s->channels_for_cur_subframe);

1134

1135 /** calculate number of scale factor bands and their offsets */

1136 s->table_idx = av_log2(s->samples_per_frame/subframe_len);

1137 s->num_bands = s->num_sfb[s->table_idx];

1138 s->cur_sfb_offsets = s->sfb_offsets[s->table_idx];

1139 cur_subwoofer_cutoff = s->subwoofer_cutoffs[s->table_idx];

1140

1141 /** configure the decoder for the current subframe */

1142 offset += s->samples_per_frame >> 1;

1143

1144 for (i = 0; i < s->channels_for_cur_subframe; i++) {

1145 int c = s->channel_indexes_for_cur_subframe[i];

1146

1147 s->channel[c].coeffs = &s->channel[c].out[offset];

1148 }

1149

1150 s->subframe_len = subframe_len;

1151 s->esc_len = av_log2(s->subframe_len - 1) + 1;

1152

1153 /** skip extended header if any */

1154 if (get_bits1(&s->gb)) {

1155 int num_fill_bits;

1156 if (!(num_fill_bits = get_bits(&s->gb, 2))) {

1157 int len = get_bits(&s->gb, 4);

1158 num_fill_bits = (len ? get_bits(&s->gb, len) : 0) + 1;

1159 }

1160

1161 if (num_fill_bits >= 0) {

1162 if (get_bits_count(&s->gb) + num_fill_bits > s->num_saved_bits) {

1163 av_log(s->avctx, AV_LOG_ERROR, "invalid number of fill bits\n");

1164 return AVERROR_INVALIDDATA;

1165 }

1166

1167 skip_bits_long(&s->gb, num_fill_bits);

1168 }

1169 }

1170

1171 /** no idea for what the following bit is used */

1172 if (get_bits1(&s->gb)) {

1173 avpriv_request_sample(s->avctx, "Reserved bit");

1174 return AVERROR_PATCHWELCOME;

1175 }

1176

1177

1178 if (decode_channel_transform(s) < 0)

1179 return AVERROR_INVALIDDATA;

1180

1181

1182 for (i = 0; i < s->channels_for_cur_subframe; i++) {

1183 int c = s->channel_indexes_for_cur_subframe[i];

1184 if ((s->channel[c].transmit_coefs = get_bits1(&s->gb)))

1185 transmit_coeffs = 1;

1186 }

1187

1188 av_assert0(s->subframe_len <= WMAPRO_BLOCK_MAX_SIZE);

1189 if (transmit_coeffs) {

1190 int step;

1191 int quant_step = 90 * s->bits_per_sample >> 4;

1192

1193 /** decode number of vector coded coefficients */

1194 if ((s->transmit_num_vec_coeffs = get_bits1(&s->gb))) {

1195 int num_bits = av_log2((s->subframe_len + 3)/4) + 1;

1196 for (i = 0; i < s->channels_for_cur_subframe; i++) {

1197 int c = s->channel_indexes_for_cur_subframe[i];

1198 int num_vec_coeffs = get_bits(&s->gb, num_bits) << 2;

1199 if (num_vec_coeffs > s->subframe_len) {

1200 av_log(s->avctx, AV_LOG_ERROR, "num_vec_coeffs %d is too large\n", num_vec_coeffs);

1201 return AVERROR_INVALIDDATA;

1202 }

1203 av_assert0(num_vec_coeffs + offset <= FF_ARRAY_ELEMS(s->channel[c].out));

1204 s->channel[c].num_vec_coeffs = num_vec_coeffs;

1205 }

1206 } else {

1207 for (i = 0; i < s->channels_for_cur_subframe; i++) {

1208 int c = s->channel_indexes_for_cur_subframe[i];

1209 s->channel[c].num_vec_coeffs = s->subframe_len;

1210 }

1211 }

1212 /** decode quantization step */

1213 step = get_sbits(&s->gb, 6);

1214 quant_step += step;

1215 if (step == -32 || step == 31) {

1216 const int sign = (step == 31) - 1;

1217 int quant = 0;

1218 while (get_bits_count(&s->gb) + 5 < s->num_saved_bits &&

1219 (step = get_bits(&s->gb, 5)) == 31) {

1220 quant += 31;

1221 }

1222 quant_step += ((quant + step) ^ sign) - sign;

1223 }

1224 if (quant_step < 0) {

1225 av_log(s->avctx, AV_LOG_DEBUG, "negative quant step\n");

1226 }

1227

1228 /** decode quantization step modifiers for every channel */

1229

1230 if (s->channels_for_cur_subframe == 1) {

1231 s->channel[s->channel_indexes_for_cur_subframe[0]].quant_step = quant_step;

1232 } else {

1233 int modifier_len = get_bits(&s->gb, 3);

1234 for (i = 0; i < s->channels_for_cur_subframe; i++) {

1235 int c = s->channel_indexes_for_cur_subframe[i];

1236 s->channel[c].quant_step = quant_step;

1237 if (get_bits1(&s->gb)) {

1238 if (modifier_len) {

1239 s->channel[c].quant_step += get_bits(&s->gb, modifier_len) + 1;

1240 } else

1241 ++s->channel[c].quant_step;

1242 }

1243 }

1244 }

1245

1246 /** decode scale factors */

1247 if (decode_scale_factors(s) < 0)

1248 return AVERROR_INVALIDDATA;

1249 }

1250

1251 av_dlog(s->avctx, "BITSTREAM: subframe header length was %i\n",

1252 get_bits_count(&s->gb) - s->subframe_offset);

1253

1254 /** parse coefficients */

1255 for (i = 0; i < s->channels_for_cur_subframe; i++) {

1256 int c = s->channel_indexes_for_cur_subframe[i];

1257 if (s->channel[c].transmit_coefs &&

1258 get_bits_count(&s->gb) < s->num_saved_bits) {

1259 decode_coeffs(s, c);

1260 } else

1261 memset(s->channel[c].coeffs, 0,

1262 sizeof(*s->channel[c].coeffs) * subframe_len);

1263 }

1264

1265 av_dlog(s->avctx, "BITSTREAM: subframe length was %i\n",

1266 get_bits_count(&s->gb) - s->subframe_offset);

1267

1268 if (transmit_coeffs) {

1269 FFTContext *mdct = &s->mdct_ctx[av_log2(subframe_len) - WMAPRO_BLOCK_MIN_BITS];

1270 /** reconstruct the per channel data */

1271 inverse_channel_transform(s);

1272 for (i = 0; i < s->channels_for_cur_subframe; i++) {

1273 int c = s->channel_indexes_for_cur_subframe[i];

1274 const int* sf = s->channel[c].scale_factors;

1275 int b;

1276

1277 if (c == s->lfe_channel)

1278 memset(&s->tmp[cur_subwoofer_cutoff], 0, sizeof(*s->tmp) *

1279 (subframe_len - cur_subwoofer_cutoff));

1280

1281 /** inverse quantization and rescaling */

1282 for (b = 0; b < s->num_bands; b++) {

1283 const int end = FFMIN(s->cur_sfb_offsets[b+1], s->subframe_len);

1284 const int exp = s->channel[c].quant_step -

1285 (s->channel[c].max_scale_factor - *sf++) *

1286 s->channel[c].scale_factor_step;

1287 const float quant = pow(10.0, exp / 20.0);

1288 int start = s->cur_sfb_offsets[b];

1289 s->fdsp.vector_fmul_scalar(s->tmp + start,

1290 s->channel[c].coeffs + start,

1291 quant, end - start);

1292 }

1293

1294 /** apply imdct (imdct_half == DCTIV with reverse) */

1295 mdct->imdct_half(mdct, s->channel[c].coeffs, s->tmp);

1296 }

1297 }

1298

1299 /** window and overlapp-add */

1300 wmapro_window(s);

1301

1302 /** handled one subframe */

1303 for (i = 0; i < s->channels_for_cur_subframe; i++) {

1304 int c = s->channel_indexes_for_cur_subframe[i];

1305 if (s->channel[c].cur_subframe >= s->channel[c].num_subframes) {

1306 av_log(s->avctx, AV_LOG_ERROR, "broken subframe\n");

1307 return AVERROR_INVALIDDATA;

1308 }

1309 ++s->channel[c].cur_subframe;

1310 }

1311

1312 return 0;

1313 }

1314

1315 /**

1316 *@brief Decode one WMA frame.

1317 *@param s codec context

1318 *@return 0 if the trailer bit indicates that this is the last frame,

1319 * 1 if there are additional frames

1320 */

1321 static int decode_frame(WMAProDecodeCtx *s, AVFrame *frame, int *got_frame_ptr)

1322 {

1323 AVCodecContext *avctx = s->avctx;

1324 GetBitContext* gb = &s->gb;

1325 int more_frames = 0;

1326 int len = 0;

1327 int i, ret;

1328

1329 /** get frame length */

1330 if (s->len_prefix)

1331 len = get_bits(gb, s->log2_frame_size);

1332

1333 av_dlog(s->avctx, "decoding frame with length %x\n", len);

1334

1335 /** decode tile information */

1336 if (decode_tilehdr(s)) {

1337 s->packet_loss = 1;

1338 return 0;

1339 }

1340

1341 /** read postproc transform */

1342 if (s->avctx->channels > 1 && get_bits1(gb)) {

1343 if (get_bits1(gb)) {

1344 for (i = 0; i < avctx->channels * avctx->channels; i++)

1345 skip_bits(gb, 4);

1346 }

1347 }

1348

1349 /** read drc info */

1350 if (s->dynamic_range_compression) {

1351 s->drc_gain = get_bits(gb, 8);

1352 av_dlog(s->avctx, "drc_gain %i\n", s->drc_gain);

1353 }

1354

1355 /** no idea what these are for, might be the number of samples

1356 that need to be skipped at the beginning or end of a stream */

1357 if (get_bits1(gb)) {

1358 int av_unused skip;

1359

1360 /** usually true for the first frame */

1361 if (get_bits1(gb)) {

1362 skip = get_bits(gb, av_log2(s->samples_per_frame * 2));

1363 av_dlog(s->avctx, "start skip: %i\n", skip);

1364 }

1365

1366 /** sometimes true for the last frame */

1367 if (get_bits1(gb)) {

1368 skip = get_bits(gb, av_log2(s->samples_per_frame * 2));

1369 av_dlog(s->avctx, "end skip: %i\n", skip);

1370 }

1371

1372 }

1373

1374 av_dlog(s->avctx, "BITSTREAM: frame header length was %i\n",

1375 get_bits_count(gb) - s->frame_offset);

1376

1377 /** reset subframe states */

1378 s->parsed_all_subframes = 0;

1379 for (i = 0; i < avctx->channels; i++) {

1380 s->channel[i].decoded_samples = 0;

1381 s->channel[i].cur_subframe = 0;

1382 s->channel[i].reuse_sf = 0;

1383 }

1384

1385 /** decode all subframes */

1386 while (!s->parsed_all_subframes) {

1387 if (decode_subframe(s) < 0) {

1388 s->packet_loss = 1;

1389 return 0;

1390 }

1391 }

1392

1393 /* get output buffer */

1394 frame->nb_samples = s->samples_per_frame;

1395 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) {

1396 s->packet_loss = 1;

1397 return 0;

1398 }

1399

1400 /** copy samples to the output buffer */

1401 for (i = 0; i < avctx->channels; i++)

1402 memcpy(frame->extended_data[i], s->channel[i].out,

1403 s->samples_per_frame * sizeof(*s->channel[i].out));

1404

1405 for (i = 0; i < avctx->channels; i++) {

1406 /** reuse second half of the IMDCT output for the next frame */

1407 memcpy(&s->channel[i].out[0],

1408 &s->channel[i].out[s->samples_per_frame],

1409 s->samples_per_frame * sizeof(*s->channel[i].out) >> 1);

1410 }

1411

1412 if (s->skip_frame) {

1413 s->skip_frame = 0;

1414 *got_frame_ptr = 0;

1415 av_frame_unref(frame);

1416 } else {

1417 *got_frame_ptr = 1;

1418 }

1419

1420 if (s->len_prefix) {

1421 if (len != (get_bits_count(gb) - s->frame_offset) + 2) {

1422 /** FIXME: not sure if this is always an error */

1423 av_log(s->avctx, AV_LOG_ERROR,

1424 "frame[%i] would have to skip %i bits\n", s->frame_num,

1425 len - (get_bits_count(gb) - s->frame_offset) - 1);

1426 s->packet_loss = 1;

1427 return 0;

1428 }

1429

1430 /** skip the rest of the frame data */

1431 skip_bits_long(gb, len - (get_bits_count(gb) - s->frame_offset) - 1);

1432 } else {

1433 while (get_bits_count(gb) < s->num_saved_bits && get_bits1(gb) == 0) {

1434 }

1435 }

1436

1437 /** decode trailer bit */

1438 more_frames = get_bits1(gb);

1439

1440 ++s->frame_num;

1441 return more_frames;

1442 }

1443

1444 /**

1445 *@brief Calculate remaining input buffer length.

1446 *@param s codec context

1447 *@param gb bitstream reader context

1448 *@return remaining size in bits

1449 */

1450 static int remaining_bits(WMAProDecodeCtx *s, GetBitContext *gb)

1451 {

1452 return s->buf_bit_size - get_bits_count(gb);

1453 }

1454

1455 /**

1456 *@brief Fill the bit reservoir with a (partial) frame.

1457 *@param s codec context

1458 *@param gb bitstream reader context

1459 *@param len length of the partial frame

1460 *@param append decides whether to reset the buffer or not

1461 */

1462 static void save_bits(WMAProDecodeCtx *s, GetBitContext* gb, int len,

1463 int append)

1464 {

1465 int buflen;

1466

1467 /** when the frame data does not need to be concatenated, the input buffer

1468 is reset and additional bits from the previous frame are copied

1469 and skipped later so that a fast byte copy is possible */

1470

1471 if (!append) {

1472 s->frame_offset = get_bits_count(gb) & 7;

1473 s->num_saved_bits = s->frame_offset;

1474 init_put_bits(&s->pb, s->frame_data, MAX_FRAMESIZE);

1475 }

1476

1477 buflen = (put_bits_count(&s->pb) + len + 8) >> 3;

1478

1479 if (len <= 0 || buflen > MAX_FRAMESIZE) {

1480 avpriv_request_sample(s->avctx, "Too small input buffer");

1481 s->packet_loss = 1;

1482 return;

1483 }

1484

1485 av_assert0(len <= put_bits_left(&s->pb));

1486

1487 s->num_saved_bits += len;

1488 if (!append) {

1489 avpriv_copy_bits(&s->pb, gb->buffer + (get_bits_count(gb) >> 3),

1490 s->num_saved_bits);

1491 } else {

1492 int align = 8 - (get_bits_count(gb) & 7);

1493 align = FFMIN(align, len);

1494 put_bits(&s->pb, align, get_bits(gb, align));

1495 len -= align;

1496 avpriv_copy_bits(&s->pb, gb->buffer + (get_bits_count(gb) >> 3), len);

1497 }

1498 skip_bits_long(gb, len);

1499

1500 {

1501 PutBitContext tmp = s->pb;

1502 flush_put_bits(&tmp);

1503 }

1504

1505 init_get_bits(&s->gb, s->frame_data, s->num_saved_bits);

1506 skip_bits(&s->gb, s->frame_offset);

1507 }

1508

1509 /**

1510 *@brief Decode a single WMA packet.

1511 *@param avctx codec context

1512 *@param data the output buffer

1513 *@param avpkt input packet

1514 *@return number of bytes that were read from the input buffer

1515 */

1516 static int decode_packet(AVCodecContext *avctx, void *data,

1517 int *got_frame_ptr, AVPacket* avpkt)

1518 {

1519 WMAProDecodeCtx *s = avctx->priv_data;

1520 GetBitContext* gb = &s->pgb;

1521 const uint8_t* buf = avpkt->data;

1522 int buf_size = avpkt->size;

1523 int num_bits_prev_frame;

1524 int packet_sequence_number;

1525

1526 *got_frame_ptr = 0;

1527

1528 if (s->packet_done || s->packet_loss) {

1529 s->packet_done = 0;

1530

1531 /** sanity check for the buffer length */

1532 if (buf_size < avctx->block_align) {

1533 av_log(avctx, AV_LOG_ERROR, "Input packet too small (%d < %d)\n",

1534 buf_size, avctx->block_align);

1535 return AVERROR_INVALIDDATA;

1536 }

1537

1538 s->next_packet_start = buf_size - avctx->block_align;

1539 buf_size = avctx->block_align;

1540 s->buf_bit_size = buf_size << 3;

1541

1542 /** parse packet header */

1543 init_get_bits(gb, buf, s->buf_bit_size);

1544 packet_sequence_number = get_bits(gb, 4);

1545 skip_bits(gb, 2);

1546

1547 /** get number of bits that need to be added to the previous frame */

1548 num_bits_prev_frame = get_bits(gb, s->log2_frame_size);

1549 av_dlog(avctx, "packet[%d]: nbpf %x\n", avctx->frame_number,

1550 num_bits_prev_frame);

1551

1552 /** check for packet loss */

1553 if (!s->packet_loss &&

1554 ((s->packet_sequence_number + 1) & 0xF) != packet_sequence_number) {

1555 s->packet_loss = 1;

1556 av_log(avctx, AV_LOG_ERROR, "Packet loss detected! seq %x vs %x\n",

1557 s->packet_sequence_number, packet_sequence_number);

1558 }

1559 s->packet_sequence_number = packet_sequence_number;

1560

1561 if (num_bits_prev_frame > 0) {

1562 int remaining_packet_bits = s->buf_bit_size - get_bits_count(gb);

1563 if (num_bits_prev_frame >= remaining_packet_bits) {

1564 num_bits_prev_frame = remaining_packet_bits;

1565 s->packet_done = 1;

1566 }

1567

1568 /** append the previous frame data to the remaining data from the

1569 previous packet to create a full frame */

1570 save_bits(s, gb, num_bits_prev_frame, 1);

1571 av_dlog(avctx, "accumulated %x bits of frame data\n",

1572 s->num_saved_bits - s->frame_offset);

1573

1574 /** decode the cross packet frame if it is valid */

1575 if (!s->packet_loss)

1576 decode_frame(s, data, got_frame_ptr);

1577 } else if (s->num_saved_bits - s->frame_offset) {

1578 av_dlog(avctx, "ignoring %x previously saved bits\n",

1579 s->num_saved_bits - s->frame_offset);

1580 }

1581

1582 if (s->packet_loss) {

1583 /** reset number of saved bits so that the decoder

1584 does not start to decode incomplete frames in the

1585 s->len_prefix == 0 case */

1586 s->num_saved_bits = 0;

1587 s->packet_loss = 0;

1588 }

1589

1590 } else {

1591 int frame_size;

1592 s->buf_bit_size = (avpkt->size - s->next_packet_start) << 3;

1593 init_get_bits(gb, avpkt->data, s->buf_bit_size);

1594 skip_bits(gb, s->packet_offset);

1595 if (s->len_prefix && remaining_bits(s, gb) > s->log2_frame_size &&

1596 (frame_size = show_bits(gb, s->log2_frame_size)) &&

1597 frame_size <= remaining_bits(s, gb)) {

1598 save_bits(s, gb, frame_size, 0);

1599 if (!s->packet_loss)

1600 s->packet_done = !decode_frame(s, data, got_frame_ptr);

1601 } else if (!s->len_prefix

1602 && s->num_saved_bits > get_bits_count(&s->gb)) {

1603 /** when the frames do not have a length prefix, we don't know

1604 the compressed length of the individual frames

1605 however, we know what part of a new packet belongs to the

1606 previous frame

1607 therefore we save the incoming packet first, then we append

1608 the "previous frame" data from the next packet so that

1609 we get a buffer that only contains full frames */

1610 s->packet_done = !decode_frame(s, data, got_frame_ptr);

1611 } else

1612 s->packet_done = 1;

1613 }

1614

1615 if (s->packet_done && !s->packet_loss &&

1616 remaining_bits(s, gb) > 0) {

1617 /** save the rest of the data so that it can be decoded

1618 with the next packet */

1619 save_bits(s, gb, remaining_bits(s, gb), 0);

1620 }

1621

1622 s->packet_offset = get_bits_count(gb) & 7;

1623 if (s->packet_loss)

1624 return AVERROR_INVALIDDATA;

1625

1626 return get_bits_count(gb) >> 3;

1627 }

1628

1629 /**

1630 *@brief Clear decoder buffers (for seeking).

1631 *@param avctx codec context

1632 */

1633 static void flush(AVCodecContext *avctx)

1634 {

1635 WMAProDecodeCtx *s = avctx->priv_data;

1636 int i;

1637 /** reset output buffer as a part of it is used during the windowing of a

1638 new frame */

1639 for (i = 0; i < avctx->channels; i++)

1640 memset(s->channel[i].out, 0, s->samples_per_frame *

1641 sizeof(*s->channel[i].out));

1642 s->packet_loss = 1;

1643 }

1644

1645

1646 /**

1647 *@brief wmapro decoder

1648 */

1649 AVCodec ff_wmapro_decoder = {

1650 .name = "wmapro",

1651 .long_name = NULL_IF_CONFIG_SMALL("Windows Media Audio 9 Professional"),

1652 .type = AVMEDIA_TYPE_AUDIO,

1653 .id = AV_CODEC_ID_WMAPRO,

1654 .priv_data_size = sizeof(WMAProDecodeCtx),

1655 .init = decode_init,

1656 .close = decode_end,

1657 .decode = decode_packet,

1658 .capabilities = CODEC_CAP_SUBFRAMES | CODEC_CAP_DR1,

1659 .flush = flush,

1660 .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,

1661 AV_SAMPLE_FMT_NONE },

1662 };

Generated on Sat Jan 25 2014 19:51:57 for FFmpeg by doxygen 1.8.2