| 1 | /* |
| 2 | * Opus decoder/demuxer common functions |
| 3 | * Copyright (c) 2012 Andrew D'Addesio |
| 4 | * Copyright (c) 2013-2014 Mozilla Corporation |
| 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 | */ |
| 22 | |
| 23 | #ifndef AVCODEC_OPUS_H |
| 24 | #define AVCODEC_OPUS_H |
| 25 | |
| 26 | #include <stdint.h> |
| 27 | |
| 28 | #include "libavutil/audio_fifo.h" |
| 29 | #include "libavutil/float_dsp.h" |
| 30 | #include "libavutil/frame.h" |
| 31 | |
| 32 | #include "libswresample/swresample.h" |
| 33 | |
| 34 | #include "avcodec.h" |
| 35 | #include "get_bits.h" |
| 36 | |
| 37 | #define MAX_FRAME_SIZE 1275 |
| 38 | #define MAX_FRAMES 48 |
| 39 | #define MAX_PACKET_DUR 5760 |
| 40 | |
| 41 | #define CELT_SHORT_BLOCKSIZE 120 |
| 42 | #define CELT_OVERLAP CELT_SHORT_BLOCKSIZE |
| 43 | #define CELT_MAX_LOG_BLOCKS 3 |
| 44 | #define CELT_MAX_FRAME_SIZE (CELT_SHORT_BLOCKSIZE * (1 << CELT_MAX_LOG_BLOCKS)) |
| 45 | #define CELT_MAX_BANDS 21 |
| 46 | #define CELT_VECTORS 11 |
| 47 | #define CELT_ALLOC_STEPS 6 |
| 48 | #define CELT_FINE_OFFSET 21 |
| 49 | #define CELT_MAX_FINE_BITS 8 |
| 50 | #define CELT_NORM_SCALE 16384 |
| 51 | #define CELT_QTHETA_OFFSET 4 |
| 52 | #define CELT_QTHETA_OFFSET_TWOPHASE 16 |
| 53 | #define CELT_DEEMPH_COEFF 0.85000610f |
| 54 | #define CELT_POSTFILTER_MINPERIOD 15 |
| 55 | #define CELT_ENERGY_SILENCE (-28.0f) |
| 56 | |
| 57 | #define SILK_HISTORY 322 |
| 58 | #define SILK_MAX_LPC 16 |
| 59 | |
| 60 | #define ROUND_MULL(a,b,s) (((MUL64(a, b) >> ((s) - 1)) + 1) >> 1) |
| 61 | #define ROUND_MUL16(a,b) ((MUL16(a, b) + 16384) >> 15) |
| 62 | #define opus_ilog(i) (av_log2(i) + !!(i)) |
| 63 | |
| 64 | #define OPUS_TS_HEADER 0x7FE0 // 0x3ff (11 bits) |
| 65 | #define OPUS_TS_MASK 0xFFE0 // top 11 bits |
| 66 | |
| 67 | static const uint8_t opus_default_extradata[30] = { |
| 68 | 'O', 'p', 'u', 's', 'H', 'e', 'a', 'd', |
| 69 | 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
| 70 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
| 71 | }; |
| 72 | |
| 73 | enum OpusMode { |
| 74 | OPUS_MODE_SILK, |
| 75 | OPUS_MODE_HYBRID, |
| 76 | OPUS_MODE_CELT |
| 77 | }; |
| 78 | |
| 79 | enum OpusBandwidth { |
| 80 | OPUS_BANDWIDTH_NARROWBAND, |
| 81 | OPUS_BANDWIDTH_MEDIUMBAND, |
| 82 | OPUS_BANDWIDTH_WIDEBAND, |
| 83 | OPUS_BANDWIDTH_SUPERWIDEBAND, |
| 84 | OPUS_BANDWIDTH_FULLBAND |
| 85 | }; |
| 86 | |
| 87 | typedef struct RawBitsContext { |
| 88 | const uint8_t *position; |
| 89 | unsigned int bytes; |
| 90 | unsigned int cachelen; |
| 91 | unsigned int cacheval; |
| 92 | } RawBitsContext; |
| 93 | |
| 94 | typedef struct OpusRangeCoder { |
| 95 | GetBitContext gb; |
| 96 | RawBitsContext rb; |
| 97 | unsigned int range; |
| 98 | unsigned int value; |
| 99 | unsigned int total_read_bits; |
| 100 | } OpusRangeCoder; |
| 101 | |
| 102 | typedef struct SilkContext SilkContext; |
| 103 | |
| 104 | typedef struct CeltContext CeltContext; |
| 105 | |
| 106 | typedef struct OpusPacket { |
| 107 | int packet_size; /**< packet size */ |
| 108 | int data_size; /**< size of the useful data -- packet size - padding */ |
| 109 | int code; /**< packet code: specifies the frame layout */ |
| 110 | int stereo; /**< whether this packet is mono or stereo */ |
| 111 | int vbr; /**< vbr flag */ |
| 112 | int config; /**< configuration: tells the audio mode, |
| 113 | ** bandwidth, and frame duration */ |
| 114 | int frame_count; /**< frame count */ |
| 115 | int frame_offset[MAX_FRAMES]; /**< frame offsets */ |
| 116 | int frame_size[MAX_FRAMES]; /**< frame sizes */ |
| 117 | int frame_duration; /**< frame duration, in samples @ 48kHz */ |
| 118 | enum OpusMode mode; /**< mode */ |
| 119 | enum OpusBandwidth bandwidth; /**< bandwidth */ |
| 120 | } OpusPacket; |
| 121 | |
| 122 | typedef struct OpusStreamContext { |
| 123 | AVCodecContext *avctx; |
| 124 | int output_channels; |
| 125 | |
| 126 | OpusRangeCoder rc; |
| 127 | OpusRangeCoder redundancy_rc; |
| 128 | SilkContext *silk; |
| 129 | CeltContext *celt; |
| 130 | AVFloatDSPContext *fdsp; |
| 131 | |
| 132 | float silk_buf[2][960]; |
| 133 | float *silk_output[2]; |
| 134 | DECLARE_ALIGNED(32, float, celt_buf)[2][960]; |
| 135 | float *celt_output[2]; |
| 136 | |
| 137 | float redundancy_buf[2][960]; |
| 138 | float *redundancy_output[2]; |
| 139 | |
| 140 | /* data buffers for the final output data */ |
| 141 | float *out[2]; |
| 142 | int out_size; |
| 143 | |
| 144 | float *out_dummy; |
| 145 | int out_dummy_allocated_size; |
| 146 | |
| 147 | SwrContext *swr; |
| 148 | AVAudioFifo *celt_delay; |
| 149 | int silk_samplerate; |
| 150 | /* number of samples we still want to get from the resampler */ |
| 151 | int delayed_samples; |
| 152 | |
| 153 | OpusPacket packet; |
| 154 | |
| 155 | int redundancy_idx; |
| 156 | } OpusStreamContext; |
| 157 | |
| 158 | // a mapping between an opus stream and an output channel |
| 159 | typedef struct ChannelMap { |
| 160 | int stream_idx; |
| 161 | int channel_idx; |
| 162 | |
| 163 | // when a single decoded channel is mapped to multiple output channels, we |
| 164 | // write to the first output directly and copy from it to the others |
| 165 | // this field is set to 1 for those copied output channels |
| 166 | int copy; |
| 167 | // this is the index of the output channel to copy from |
| 168 | int copy_idx; |
| 169 | |
| 170 | // this channel is silent |
| 171 | int silence; |
| 172 | } ChannelMap; |
| 173 | |
| 174 | typedef struct OpusContext { |
| 175 | OpusStreamContext *streams; |
| 176 | int nb_streams; |
| 177 | int nb_stereo_streams; |
| 178 | |
| 179 | AVFloatDSPContext *fdsp; |
| 180 | int16_t gain_i; |
| 181 | float gain; |
| 182 | |
| 183 | ChannelMap *channel_maps; |
| 184 | } OpusContext; |
| 185 | |
| 186 | static av_always_inline void opus_rc_normalize(OpusRangeCoder *rc) |
| 187 | { |
| 188 | while (rc->range <= 1<<23) { |
| 189 | rc->value = ((rc->value << 8) | (get_bits(&rc->gb, 8) ^ 0xFF)) & ((1u << 31) - 1); |
| 190 | rc->range <<= 8; |
| 191 | rc->total_read_bits += 8; |
| 192 | } |
| 193 | } |
| 194 | |
| 195 | static av_always_inline void opus_rc_update(OpusRangeCoder *rc, unsigned int scale, |
| 196 | unsigned int low, unsigned int high, |
| 197 | unsigned int total) |
| 198 | { |
| 199 | rc->value -= scale * (total - high); |
| 200 | rc->range = low ? scale * (high - low) |
| 201 | : rc->range - scale * (total - high); |
| 202 | opus_rc_normalize(rc); |
| 203 | } |
| 204 | |
| 205 | static av_always_inline unsigned int opus_rc_getsymbol(OpusRangeCoder *rc, const uint16_t *cdf) |
| 206 | { |
| 207 | unsigned int k, scale, total, symbol, low, high; |
| 208 | |
| 209 | total = *cdf++; |
| 210 | |
| 211 | scale = rc->range / total; |
| 212 | symbol = rc->value / scale + 1; |
| 213 | symbol = total - FFMIN(symbol, total); |
| 214 | |
| 215 | for (k = 0; cdf[k] <= symbol; k++); |
| 216 | high = cdf[k]; |
| 217 | low = k ? cdf[k-1] : 0; |
| 218 | |
| 219 | opus_rc_update(rc, scale, low, high, total); |
| 220 | |
| 221 | return k; |
| 222 | } |
| 223 | |
| 224 | static av_always_inline unsigned int opus_rc_p2model(OpusRangeCoder *rc, unsigned int bits) |
| 225 | { |
| 226 | unsigned int k, scale; |
| 227 | scale = rc->range >> bits; // in this case, scale = symbol |
| 228 | |
| 229 | if (rc->value >= scale) { |
| 230 | rc->value -= scale; |
| 231 | rc->range -= scale; |
| 232 | k = 0; |
| 233 | } else { |
| 234 | rc->range = scale; |
| 235 | k = 1; |
| 236 | } |
| 237 | opus_rc_normalize(rc); |
| 238 | return k; |
| 239 | } |
| 240 | |
| 241 | /** |
| 242 | * CELT: estimate bits of entropy that have thus far been consumed for the |
| 243 | * current CELT frame, to integer and fractional (1/8th bit) precision |
| 244 | */ |
| 245 | static av_always_inline unsigned int opus_rc_tell(const OpusRangeCoder *rc) |
| 246 | { |
| 247 | return rc->total_read_bits - av_log2(rc->range) - 1; |
| 248 | } |
| 249 | |
| 250 | static av_always_inline unsigned int opus_rc_tell_frac(const OpusRangeCoder *rc) |
| 251 | { |
| 252 | unsigned int i, total_bits, rcbuffer, range; |
| 253 | |
| 254 | total_bits = rc->total_read_bits << 3; |
| 255 | rcbuffer = av_log2(rc->range) + 1; |
| 256 | range = rc->range >> (rcbuffer-16); |
| 257 | |
| 258 | for (i = 0; i < 3; i++) { |
| 259 | int bit; |
| 260 | range = range * range >> 15; |
| 261 | bit = range >> 16; |
| 262 | rcbuffer = rcbuffer << 1 | bit; |
| 263 | range >>= bit; |
| 264 | } |
| 265 | |
| 266 | return total_bits - rcbuffer; |
| 267 | } |
| 268 | |
| 269 | /** |
| 270 | * CELT: read 1-25 raw bits at the end of the frame, backwards byte-wise |
| 271 | */ |
| 272 | static av_always_inline unsigned int opus_getrawbits(OpusRangeCoder *rc, unsigned int count) |
| 273 | { |
| 274 | unsigned int value = 0; |
| 275 | |
| 276 | while (rc->rb.bytes && rc->rb.cachelen < count) { |
| 277 | rc->rb.cacheval |= *--rc->rb.position << rc->rb.cachelen; |
| 278 | rc->rb.cachelen += 8; |
| 279 | rc->rb.bytes--; |
| 280 | } |
| 281 | |
| 282 | value = rc->rb.cacheval & ((1<<count)-1); |
| 283 | rc->rb.cacheval >>= count; |
| 284 | rc->rb.cachelen -= count; |
| 285 | rc->total_read_bits += count; |
| 286 | |
| 287 | return value; |
| 288 | } |
| 289 | |
| 290 | /** |
| 291 | * CELT: read a uniform distribution |
| 292 | */ |
| 293 | static av_always_inline unsigned int opus_rc_unimodel(OpusRangeCoder *rc, unsigned int size) |
| 294 | { |
| 295 | unsigned int bits, k, scale, total; |
| 296 | |
| 297 | bits = opus_ilog(size - 1); |
| 298 | total = (bits > 8) ? ((size - 1) >> (bits - 8)) + 1 : size; |
| 299 | |
| 300 | scale = rc->range / total; |
| 301 | k = rc->value / scale + 1; |
| 302 | k = total - FFMIN(k, total); |
| 303 | opus_rc_update(rc, scale, k, k + 1, total); |
| 304 | |
| 305 | if (bits > 8) { |
| 306 | k = k << (bits - 8) | opus_getrawbits(rc, bits - 8); |
| 307 | return FFMIN(k, size - 1); |
| 308 | } else |
| 309 | return k; |
| 310 | } |
| 311 | |
| 312 | static av_always_inline int opus_rc_laplace(OpusRangeCoder *rc, unsigned int symbol, int decay) |
| 313 | { |
| 314 | /* extends the range coder to model a Laplace distribution */ |
| 315 | int value = 0; |
| 316 | unsigned int scale, low = 0, center; |
| 317 | |
| 318 | scale = rc->range >> 15; |
| 319 | center = rc->value / scale + 1; |
| 320 | center = (1 << 15) - FFMIN(center, 1 << 15); |
| 321 | |
| 322 | if (center >= symbol) { |
| 323 | value++; |
| 324 | low = symbol; |
| 325 | symbol = 1 + ((32768 - 32 - symbol) * (16384-decay) >> 15); |
| 326 | |
| 327 | while (symbol > 1 && center >= low + 2 * symbol) { |
| 328 | value++; |
| 329 | symbol *= 2; |
| 330 | low += symbol; |
| 331 | symbol = (((symbol - 2) * decay) >> 15) + 1; |
| 332 | } |
| 333 | |
| 334 | if (symbol <= 1) { |
| 335 | int distance = (center - low) >> 1; |
| 336 | value += distance; |
| 337 | low += 2 * distance; |
| 338 | } |
| 339 | |
| 340 | if (center < low + symbol) |
| 341 | value *= -1; |
| 342 | else |
| 343 | low += symbol; |
| 344 | } |
| 345 | |
| 346 | opus_rc_update(rc, scale, low, FFMIN(low + symbol, 32768), 32768); |
| 347 | |
| 348 | return value; |
| 349 | } |
| 350 | |
| 351 | static av_always_inline unsigned int opus_rc_stepmodel(OpusRangeCoder *rc, int k0) |
| 352 | { |
| 353 | /* Use a probability of 3 up to itheta=8192 and then use 1 after */ |
| 354 | unsigned int k, scale, symbol, total = (k0+1)*3 + k0; |
| 355 | scale = rc->range / total; |
| 356 | symbol = rc->value / scale + 1; |
| 357 | symbol = total - FFMIN(symbol, total); |
| 358 | |
| 359 | k = (symbol < (k0+1)*3) ? symbol/3 : symbol - (k0+1)*2; |
| 360 | |
| 361 | opus_rc_update(rc, scale, (k <= k0) ? 3*(k+0) : (k-1-k0) + 3*(k0+1), |
| 362 | (k <= k0) ? 3*(k+1) : (k-0-k0) + 3*(k0+1), total); |
| 363 | return k; |
| 364 | } |
| 365 | |
| 366 | static av_always_inline unsigned int opus_rc_trimodel(OpusRangeCoder *rc, int qn) |
| 367 | { |
| 368 | unsigned int k, scale, symbol, total, low, center; |
| 369 | |
| 370 | total = ((qn>>1) + 1) * ((qn>>1) + 1); |
| 371 | scale = rc->range / total; |
| 372 | center = rc->value / scale + 1; |
| 373 | center = total - FFMIN(center, total); |
| 374 | |
| 375 | if (center < total >> 1) { |
| 376 | k = (ff_sqrt(8 * center + 1) - 1) >> 1; |
| 377 | low = k * (k + 1) >> 1; |
| 378 | symbol = k + 1; |
| 379 | } else { |
| 380 | k = (2*(qn + 1) - ff_sqrt(8*(total - center - 1) + 1)) >> 1; |
| 381 | low = total - ((qn + 1 - k) * (qn + 2 - k) >> 1); |
| 382 | symbol = qn + 1 - k; |
| 383 | } |
| 384 | |
| 385 | opus_rc_update(rc, scale, low, low + symbol, total); |
| 386 | |
| 387 | return k; |
| 388 | } |
| 389 | |
| 390 | int ff_opus_parse_packet(OpusPacket *pkt, const uint8_t *buf, int buf_size, |
| 391 | int self_delimited); |
| 392 | |
| 393 | int ff_opus_parse_extradata(AVCodecContext *avctx, OpusContext *s); |
| 394 | |
| 395 | int ff_silk_init(AVCodecContext *avctx, SilkContext **ps, int output_channels); |
| 396 | void ff_silk_free(SilkContext **ps); |
| 397 | void ff_silk_flush(SilkContext *s); |
| 398 | |
| 399 | /** |
| 400 | * Decode the LP layer of one Opus frame (which may correspond to several SILK |
| 401 | * frames). |
| 402 | */ |
| 403 | int ff_silk_decode_superframe(SilkContext *s, OpusRangeCoder *rc, |
| 404 | float *output[2], |
| 405 | enum OpusBandwidth bandwidth, int coded_channels, |
| 406 | int duration_ms); |
| 407 | |
| 408 | int ff_celt_init(AVCodecContext *avctx, CeltContext **s, int output_channels); |
| 409 | |
| 410 | void ff_celt_free(CeltContext **s); |
| 411 | |
| 412 | void ff_celt_flush(CeltContext *s); |
| 413 | |
| 414 | int ff_celt_decode_frame(CeltContext *s, OpusRangeCoder *rc, |
| 415 | float **output, int coded_channels, int frame_size, |
| 416 | int startband, int endband); |
| 417 | |
| 418 | extern const float ff_celt_window2[120]; |
| 419 | |
| 420 | #endif /* AVCODEC_OPUS_H */ |