1/* 2 * MLP parser 3 * Copyright (c) 2007 Ian Caulfield 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 */ 21 22/** 23 * @file 24 * MLP parser 25 */ 26 27#include <stdint.h> 28 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" 36 37static 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}; 41 42static 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}; 46 47const 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}; 71 72static 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}; 76 77static 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}; 92 93static int mlp_samplerate(int in) 94{ 95 if (in == 0xF) 96 return 0; 97 98 return (in & 8 ? 44100 : 48000) << (in & 7) ; 99} 100 101static 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 111uint64_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/** Read a major sync info header - contains high level information about 123 * the stream - sample rate, channel arrangement etc. Most of this 124 * information is not actually necessary for decoding, only for playback. 125 * gb must be a freshly initialized GetBitContext with no bits read. 126 */ 127 128int ff_mlp_read_major_sync(void *log, MLPHeaderInfo *mh, GetBitContext *gb) 129{ 130 int ratebits, channel_arrangement; 131 uint16_t checksum; 132 133 av_assert1(get_bits_count(gb) == 0); 134 135 if (gb->size_in_bits < 28 << 3) { 136 av_log(log, AV_LOG_ERROR, "packet too short, unable to read major sync\n"); 137 return -1; 138 } 139 140 checksum = ff_mlp_checksum16(gb->buffer, 26); 141 if (checksum != AV_RL16(gb->buffer+26)) { 142 av_log(log, AV_LOG_ERROR, "major sync info header checksum error\n"); 143 return AVERROR_INVALIDDATA; 144 } 145 146 if (get_bits_long(gb, 24) != 0xf8726f) /* Sync words */ 147 return AVERROR_INVALIDDATA; 148 149 mh->stream_type = get_bits(gb, 8); 150 151 if (mh->stream_type == 0xbb) { 152 mh->group1_bits = mlp_quants[get_bits(gb, 4)]; 153 mh->group2_bits = mlp_quants[get_bits(gb, 4)]; 154 155 ratebits = get_bits(gb, 4); 156 mh->group1_samplerate = mlp_samplerate(ratebits); 157 mh->group2_samplerate = mlp_samplerate(get_bits(gb, 4)); 158 159 skip_bits(gb, 11); 160 161 mh->channel_arrangement= 162 channel_arrangement = get_bits(gb, 5); 163 mh->channels_mlp = mlp_channels[channel_arrangement]; 164 mh->channel_layout_mlp = ff_mlp_layout[channel_arrangement]; 165 } else if (mh->stream_type == 0xba) { 166 mh->group1_bits = 24; // TODO: Is this information actually conveyed anywhere? 167 mh->group2_bits = 0; 168 169 ratebits = get_bits(gb, 4); 170 mh->group1_samplerate = mlp_samplerate(ratebits); 171 mh->group2_samplerate = 0; 172 173 skip_bits(gb, 4); 174 175 mh->channel_modifier_thd_stream0 = get_bits(gb, 2); 176 mh->channel_modifier_thd_stream1 = get_bits(gb, 2); 177 178 mh->channel_arrangement= 179 channel_arrangement = get_bits(gb, 5); 180 mh->channels_thd_stream1 = truehd_channels(channel_arrangement); 181 mh->channel_layout_thd_stream1 = ff_truehd_layout(channel_arrangement); 182 183 mh->channel_modifier_thd_stream2 = get_bits(gb, 2); 184 185 channel_arrangement = get_bits(gb, 13); 186 mh->channels_thd_stream2 = truehd_channels(channel_arrangement); 187 mh->channel_layout_thd_stream2 = ff_truehd_layout(channel_arrangement); 188 } else 189 return AVERROR_INVALIDDATA; 190 191 mh->access_unit_size = 40 << (ratebits & 7); 192 mh->access_unit_size_pow2 = 64 << (ratebits & 7); 193 194 skip_bits_long(gb, 48); 195 196 mh->is_vbr = get_bits1(gb); 197 198 mh->peak_bitrate = (get_bits(gb, 15) * mh->group1_samplerate + 8) >> 4; 199 200 mh->num_substreams = get_bits(gb, 4); 201 202 skip_bits_long(gb, 4 + 11 * 8); 203 204 return 0; 205} 206 207typedef struct MLPParseContext 208{ 209 ParseContext pc; 210 211 int bytes_left; 212 213 int in_sync; 214 215 int num_substreams; 216} MLPParseContext; 217 218static av_cold int mlp_init(AVCodecParserContext *s) 219{ 220 ff_mlp_init_crc(); 221 return 0; 222} 223 224static int mlp_parse(AVCodecParserContext *s, 225 AVCodecContext *avctx, 226 const uint8_t **poutbuf, int *poutbuf_size, 227 const uint8_t *buf, int buf_size) 228{ 229 MLPParseContext *mp = s->priv_data; 230 int sync_present; 231 uint8_t parity_bits; 232 int next; 233 int ret; 234 int i, p = 0; 235 236 *poutbuf_size = 0; 237 if (buf_size == 0) 238 return 0; 239 240 if (!mp->in_sync) { 241 // Not in sync - find a major sync header 242 243 for (i = 0; i < buf_size; i++) { 244 mp->pc.state = (mp->pc.state << 8) | buf[i]; 245 if ((mp->pc.state & 0xfffffffe) == 0xf8726fba && 246 // ignore if we do not have the data for the start of header 247 mp->pc.index + i >= 7) { 248 mp->in_sync = 1; 249 mp->bytes_left = 0; 250 break; 251 } 252 } 253 254 if (!mp->in_sync) { 255 if (ff_combine_frame(&mp->pc, END_NOT_FOUND, &buf, &buf_size) != -1) 256 av_log(avctx, AV_LOG_WARNING, "ff_combine_frame failed\n"); 257 return buf_size; 258 } 259 260 if ((ret = ff_combine_frame(&mp->pc, i - 7, &buf, &buf_size)) < 0) { 261 av_log(avctx, AV_LOG_WARNING, "ff_combine_frame failed\n"); 262 return ret; 263 } 264 265 return i - 7; 266 } 267 268 if (mp->bytes_left == 0) { 269 // Find length of this packet 270 271 /* Copy overread bytes from last frame into buffer. */ 272 for(; mp->pc.overread>0; mp->pc.overread--) { 273 mp->pc.buffer[mp->pc.index++]= mp->pc.buffer[mp->pc.overread_index++]; 274 } 275 276 if (mp->pc.index + buf_size < 2) { 277 if (ff_combine_frame(&mp->pc, END_NOT_FOUND, &buf, &buf_size) != -1) 278 av_log(avctx, AV_LOG_WARNING, "ff_combine_frame failed\n"); 279 return buf_size; 280 } 281 282 mp->bytes_left = ((mp->pc.index > 0 ? mp->pc.buffer[0] : buf[0]) << 8) 283 | (mp->pc.index > 1 ? mp->pc.buffer[1] : buf[1-mp->pc.index]); 284 mp->bytes_left = (mp->bytes_left & 0xfff) * 2; 285 if (mp->bytes_left <= 0) { // prevent infinite loop 286 goto lost_sync; 287 } 288 mp->bytes_left -= mp->pc.index; 289 } 290 291 next = (mp->bytes_left > buf_size) ? END_NOT_FOUND : mp->bytes_left; 292 293 if (ff_combine_frame(&mp->pc, next, &buf, &buf_size) < 0) { 294 mp->bytes_left -= buf_size; 295 return buf_size; 296 } 297 298 mp->bytes_left = 0; 299 300 sync_present = (AV_RB32(buf + 4) & 0xfffffffe) == 0xf8726fba; 301 302 if (!sync_present) { 303 /* The first nibble of a frame is a parity check of the 4-byte 304 * access unit header and all the 2- or 4-byte substream headers. */ 305 // Only check when this isn't a sync frame - syncs have a checksum. 306 307 parity_bits = 0; 308 for (i = -1; i < mp->num_substreams; i++) { 309 parity_bits ^= buf[p++]; 310 parity_bits ^= buf[p++]; 311 312 if (i < 0 || buf[p-2] & 0x80) { 313 parity_bits ^= buf[p++]; 314 parity_bits ^= buf[p++]; 315 } 316 } 317 318 if ((((parity_bits >> 4) ^ parity_bits) & 0xF) != 0xF) { 319 av_log(avctx, AV_LOG_INFO, "mlpparse: Parity check failed.\n"); 320 goto lost_sync; 321 } 322 } else { 323 GetBitContext gb; 324 MLPHeaderInfo mh; 325 326 init_get_bits(&gb, buf + 4, (buf_size - 4) << 3); 327 if (ff_mlp_read_major_sync(avctx, &mh, &gb) < 0) 328 goto lost_sync; 329 330 avctx->bits_per_raw_sample = mh.group1_bits; 331 if (avctx->bits_per_raw_sample > 16) 332 avctx->sample_fmt = AV_SAMPLE_FMT_S32; 333 else 334 avctx->sample_fmt = AV_SAMPLE_FMT_S16; 335 avctx->sample_rate = mh.group1_samplerate; 336 s->duration = mh.access_unit_size; 337 338 if(!avctx->channels || !avctx->channel_layout) { 339 if (mh.stream_type == 0xbb) { 340 /* MLP stream */ 341#if FF_API_REQUEST_CHANNELS 342FF_DISABLE_DEPRECATION_WARNINGS 343 if (avctx->request_channels > 0 && avctx->request_channels <= 2 && 344 mh.num_substreams > 1) { 345 avctx->channels = 2; 346 avctx->channel_layout = AV_CH_LAYOUT_STEREO; 347FF_ENABLE_DEPRECATION_WARNINGS 348 } else 349#endif 350 if (avctx->request_channel_layout && 351 (avctx->request_channel_layout & AV_CH_LAYOUT_STEREO) == 352 avctx->request_channel_layout && 353 mh.num_substreams > 1) { 354 avctx->channels = 2; 355 avctx->channel_layout = AV_CH_LAYOUT_STEREO; 356 } else { 357 avctx->channels = mh.channels_mlp; 358 avctx->channel_layout = mh.channel_layout_mlp; 359 } 360 } else { /* mh.stream_type == 0xba */ 361 /* TrueHD stream */ 362#if FF_API_REQUEST_CHANNELS 363FF_DISABLE_DEPRECATION_WARNINGS 364 if (avctx->request_channels > 0 && avctx->request_channels <= 2 && 365 mh.num_substreams > 1) { 366 avctx->channels = 2; 367 avctx->channel_layout = AV_CH_LAYOUT_STEREO; 368 } else if (avctx->request_channels > 0 && 369 avctx->request_channels <= mh.channels_thd_stream1) { 370 avctx->channels = mh.channels_thd_stream1; 371 avctx->channel_layout = mh.channel_layout_thd_stream1; 372FF_ENABLE_DEPRECATION_WARNINGS 373 } else 374#endif 375 if (avctx->request_channel_layout && 376 (avctx->request_channel_layout & AV_CH_LAYOUT_STEREO) == 377 avctx->request_channel_layout && 378 mh.num_substreams > 1) { 379 avctx->channels = 2; 380 avctx->channel_layout = AV_CH_LAYOUT_STEREO; 381 } else if (!mh.channels_thd_stream2 || 382 (avctx->request_channel_layout && 383 (avctx->request_channel_layout & mh.channel_layout_thd_stream1) == 384 avctx->request_channel_layout)) { 385 avctx->channels = mh.channels_thd_stream1; 386 avctx->channel_layout = mh.channel_layout_thd_stream1; 387 } else { 388 avctx->channels = mh.channels_thd_stream2; 389 avctx->channel_layout = mh.channel_layout_thd_stream2; 390 } 391 } 392 } 393 394 if (!mh.is_vbr) /* Stream is CBR */ 395 avctx->bit_rate = mh.peak_bitrate; 396 397 mp->num_substreams = mh.num_substreams; 398 } 399 400 *poutbuf = buf; 401 *poutbuf_size = buf_size; 402 403 return next; 404 405lost_sync: 406 mp->in_sync = 0; 407 return 1; 408} 409 410AVCodecParser ff_mlp_parser = { 411 .codec_ids = { AV_CODEC_ID_MLP, AV_CODEC_ID_TRUEHD }, 412 .priv_data_size = sizeof(MLPParseContext), 413 .parser_init = mlp_init, 414 .parser_parse = mlp_parse, 415 .parser_close = ff_parse_close, 416}; 417