/* * MPEG-4 ALS decoder * Copyright (c) 2009 Thilo Borgmann * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * MPEG-4 ALS decoder * @author Thilo Borgmann */ #include #include "avcodec.h" #include "get_bits.h" #include "unary.h" #include "mpeg4audio.h" #include "bgmc.h" #include "bswapdsp.h" #include "internal.h" #include "mlz.h" #include "libavutil/samplefmt.h" #include "libavutil/crc.h" #include "libavutil/softfloat_ieee754.h" #include "libavutil/intfloat.h" #include "libavutil/intreadwrite.h" #include /** Rice parameters and corresponding index offsets for decoding the * indices of scaled PARCOR values. The table chosen is set globally * by the encoder and stored in ALSSpecificConfig. */ static const int8_t parcor_rice_table[3][20][2] = { { {-52, 4}, {-29, 5}, {-31, 4}, { 19, 4}, {-16, 4}, { 12, 3}, { -7, 3}, { 9, 3}, { -5, 3}, { 6, 3}, { -4, 3}, { 3, 3}, { -3, 2}, { 3, 2}, { -2, 2}, { 3, 2}, { -1, 2}, { 2, 2}, { -1, 2}, { 2, 2} }, { {-58, 3}, {-42, 4}, {-46, 4}, { 37, 5}, {-36, 4}, { 29, 4}, {-29, 4}, { 25, 4}, {-23, 4}, { 20, 4}, {-17, 4}, { 16, 4}, {-12, 4}, { 12, 3}, {-10, 4}, { 7, 3}, { -4, 4}, { 3, 3}, { -1, 3}, { 1, 3} }, { {-59, 3}, {-45, 5}, {-50, 4}, { 38, 4}, {-39, 4}, { 32, 4}, {-30, 4}, { 25, 3}, {-23, 3}, { 20, 3}, {-20, 3}, { 16, 3}, {-13, 3}, { 10, 3}, { -7, 3}, { 3, 3}, { 0, 3}, { -1, 3}, { 2, 3}, { -1, 2} } }; /** Scaled PARCOR values used for the first two PARCOR coefficients. * To be indexed by the Rice coded indices. * Generated by: parcor_scaled_values[i] = 32 + ((i * (i+1)) << 7) - (1 << 20) * Actual values are divided by 32 in order to be stored in 16 bits. */ static const int16_t parcor_scaled_values[] = { -1048544 / 32, -1048288 / 32, -1047776 / 32, -1047008 / 32, -1045984 / 32, -1044704 / 32, -1043168 / 32, -1041376 / 32, -1039328 / 32, -1037024 / 32, -1034464 / 32, -1031648 / 32, -1028576 / 32, -1025248 / 32, -1021664 / 32, -1017824 / 32, -1013728 / 32, -1009376 / 32, -1004768 / 32, -999904 / 32, -994784 / 32, -989408 / 32, -983776 / 32, -977888 / 32, -971744 / 32, -965344 / 32, -958688 / 32, -951776 / 32, -944608 / 32, -937184 / 32, -929504 / 32, -921568 / 32, -913376 / 32, -904928 / 32, -896224 / 32, -887264 / 32, -878048 / 32, -868576 / 32, -858848 / 32, -848864 / 32, -838624 / 32, -828128 / 32, -817376 / 32, -806368 / 32, -795104 / 32, -783584 / 32, -771808 / 32, -759776 / 32, -747488 / 32, -734944 / 32, -722144 / 32, -709088 / 32, -695776 / 32, -682208 / 32, -668384 / 32, -654304 / 32, -639968 / 32, -625376 / 32, -610528 / 32, -595424 / 32, -580064 / 32, -564448 / 32, -548576 / 32, -532448 / 32, -516064 / 32, -499424 / 32, -482528 / 32, -465376 / 32, -447968 / 32, -430304 / 32, -412384 / 32, -394208 / 32, -375776 / 32, -357088 / 32, -338144 / 32, -318944 / 32, -299488 / 32, -279776 / 32, -259808 / 32, -239584 / 32, -219104 / 32, -198368 / 32, -177376 / 32, -156128 / 32, -134624 / 32, -112864 / 32, -90848 / 32, -68576 / 32, -46048 / 32, -23264 / 32, -224 / 32, 23072 / 32, 46624 / 32, 70432 / 32, 94496 / 32, 118816 / 32, 143392 / 32, 168224 / 32, 193312 / 32, 218656 / 32, 244256 / 32, 270112 / 32, 296224 / 32, 322592 / 32, 349216 / 32, 376096 / 32, 403232 / 32, 430624 / 32, 458272 / 32, 486176 / 32, 514336 / 32, 542752 / 32, 571424 / 32, 600352 / 32, 629536 / 32, 658976 / 32, 688672 / 32, 718624 / 32, 748832 / 32, 779296 / 32, 810016 / 32, 840992 / 32, 872224 / 32, 903712 / 32, 935456 / 32, 967456 / 32, 999712 / 32, 1032224 / 32 }; /** Gain values of p(0) for long-term prediction. * To be indexed by the Rice coded indices. */ static const uint8_t ltp_gain_values [4][4] = { { 0, 8, 16, 24}, {32, 40, 48, 56}, {64, 70, 76, 82}, {88, 92, 96, 100} }; /** Inter-channel weighting factors for multi-channel correlation. * To be indexed by the Rice coded indices. */ static const int16_t mcc_weightings[] = { 204, 192, 179, 166, 153, 140, 128, 115, 102, 89, 76, 64, 51, 38, 25, 12, 0, -12, -25, -38, -51, -64, -76, -89, -102, -115, -128, -140, -153, -166, -179, -192 }; /** Tail codes used in arithmetic coding using block Gilbert-Moore codes. */ static const uint8_t tail_code[16][6] = { { 74, 44, 25, 13, 7, 3}, { 68, 42, 24, 13, 7, 3}, { 58, 39, 23, 13, 7, 3}, {126, 70, 37, 19, 10, 5}, {132, 70, 37, 20, 10, 5}, {124, 70, 38, 20, 10, 5}, {120, 69, 37, 20, 11, 5}, {116, 67, 37, 20, 11, 5}, {108, 66, 36, 20, 10, 5}, {102, 62, 36, 20, 10, 5}, { 88, 58, 34, 19, 10, 5}, {162, 89, 49, 25, 13, 7}, {156, 87, 49, 26, 14, 7}, {150, 86, 47, 26, 14, 7}, {142, 84, 47, 26, 14, 7}, {131, 79, 46, 26, 14, 7} }; enum RA_Flag { RA_FLAG_NONE, RA_FLAG_FRAMES, RA_FLAG_HEADER }; typedef struct ALSSpecificConfig { uint32_t samples; ///< number of samples, 0xFFFFFFFF if unknown int resolution; ///< 000 = 8-bit; 001 = 16-bit; 010 = 24-bit; 011 = 32-bit int floating; ///< 1 = IEEE 32-bit floating-point, 0 = integer int msb_first; ///< 1 = original CRC calculated on big-endian system, 0 = little-endian int frame_length; ///< frame length for each frame (last frame may differ) int ra_distance; ///< distance between RA frames (in frames, 0...255) enum RA_Flag ra_flag; ///< indicates where the size of ra units is stored int adapt_order; ///< adaptive order: 1 = on, 0 = off int coef_table; ///< table index of Rice code parameters int long_term_prediction; ///< long term prediction (LTP): 1 = on, 0 = off int max_order; ///< maximum prediction order (0..1023) int block_switching; ///< number of block switching levels int bgmc; ///< "Block Gilbert-Moore Code": 1 = on, 0 = off (Rice coding only) int sb_part; ///< sub-block partition int joint_stereo; ///< joint stereo: 1 = on, 0 = off int mc_coding; ///< extended inter-channel coding (multi channel coding): 1 = on, 0 = off int chan_config; ///< indicates that a chan_config_info field is present int chan_sort; ///< channel rearrangement: 1 = on, 0 = off int rlslms; ///< use "Recursive Least Square-Least Mean Square" predictor: 1 = on, 0 = off int chan_config_info; ///< mapping of channels to loudspeaker locations. Unused until setting channel configuration is implemented. int *chan_pos; ///< original channel positions int crc_enabled; ///< enable Cyclic Redundancy Checksum } ALSSpecificConfig; typedef struct ALSChannelData { int stop_flag; int master_channel; int time_diff_flag; int time_diff_sign; int time_diff_index; int weighting[6]; } ALSChannelData; typedef struct ALSDecContext { AVCodecContext *avctx; ALSSpecificConfig sconf; GetBitContext gb; BswapDSPContext bdsp; const AVCRC *crc_table; uint32_t crc_org; ///< CRC value of the original input data uint32_t crc; ///< CRC value calculated from decoded data unsigned int cur_frame_length; ///< length of the current frame to decode unsigned int frame_id; ///< the frame ID / number of the current frame unsigned int js_switch; ///< if true, joint-stereo decoding is enforced unsigned int cs_switch; ///< if true, channel rearrangement is done unsigned int num_blocks; ///< number of blocks used in the current frame unsigned int s_max; ///< maximum Rice parameter allowed in entropy coding uint8_t *bgmc_lut; ///< pointer at lookup tables used for BGMC int *bgmc_lut_status; ///< pointer at lookup table status flags used for BGMC int ltp_lag_length; ///< number of bits used for ltp lag value int *const_block; ///< contains const_block flags for all channels unsigned int *shift_lsbs; ///< contains shift_lsbs flags for all channels unsigned int *opt_order; ///< contains opt_order flags for all channels int *store_prev_samples; ///< contains store_prev_samples flags for all channels int *use_ltp; ///< contains use_ltp flags for all channels int *ltp_lag; ///< contains ltp lag values for all channels int **ltp_gain; ///< gain values for ltp 5-tap filter for a channel int *ltp_gain_buffer; ///< contains all gain values for ltp 5-tap filter int32_t **quant_cof; ///< quantized parcor coefficients for a channel int32_t *quant_cof_buffer; ///< contains all quantized parcor coefficients int32_t **lpc_cof; ///< coefficients of the direct form prediction filter for a channel int32_t *lpc_cof_buffer; ///< contains all coefficients of the direct form prediction filter int32_t *lpc_cof_reversed_buffer; ///< temporary buffer to set up a reversed versio of lpc_cof_buffer ALSChannelData **chan_data; ///< channel data for multi-channel correlation ALSChannelData *chan_data_buffer; ///< contains channel data for all channels int *reverted_channels; ///< stores a flag for each reverted channel int32_t *prev_raw_samples; ///< contains unshifted raw samples from the previous block int32_t **raw_samples; ///< decoded raw samples for each channel int32_t *raw_buffer; ///< contains all decoded raw samples including carryover samples uint8_t *crc_buffer; ///< buffer of byte order corrected samples used for CRC check MLZ* mlz; ///< masked lz decompression structure SoftFloat_IEEE754 *acf; ///< contains common multiplier for all channels int *last_acf_mantissa; ///< contains the last acf mantissa data of common multiplier for all channels int *shift_value; ///< value by which the binary point is to be shifted for all channels int *last_shift_value; ///< contains last shift value for all channels int **raw_mantissa; ///< decoded mantissa bits of the difference signal unsigned char *larray; ///< buffer to store the output of masked lz decompression int *nbits; ///< contains the number of bits to read for masked lz decompression for all samples } ALSDecContext; typedef struct ALSBlockData { unsigned int block_length; ///< number of samples within the block unsigned int ra_block; ///< if true, this is a random access block int *const_block; ///< if true, this is a constant value block int js_blocks; ///< true if this block contains a difference signal unsigned int *shift_lsbs; ///< shift of values for this block unsigned int *opt_order; ///< prediction order of this block int *store_prev_samples;///< if true, carryover samples have to be stored int *use_ltp; ///< if true, long-term prediction is used int *ltp_lag; ///< lag value for long-term prediction int *ltp_gain; ///< gain values for ltp 5-tap filter int32_t *quant_cof; ///< quantized parcor coefficients int32_t *lpc_cof; ///< coefficients of the direct form prediction int32_t *raw_samples; ///< decoded raw samples / residuals for this block int32_t *prev_raw_samples; ///< contains unshifted raw samples from the previous block int32_t *raw_other; ///< decoded raw samples of the other channel of a channel pair } ALSBlockData; static av_cold void dprint_specific_config(ALSDecContext *ctx) { #ifdef DEBUG AVCodecContext *avctx = ctx->avctx; ALSSpecificConfig *sconf = &ctx->sconf; ff_dlog(avctx, "resolution = %i\n", sconf->resolution); ff_dlog(avctx, "floating = %i\n", sconf->floating); ff_dlog(avctx, "frame_length = %i\n", sconf->frame_length); ff_dlog(avctx, "ra_distance = %i\n", sconf->ra_distance); ff_dlog(avctx, "ra_flag = %i\n", sconf->ra_flag); ff_dlog(avctx, "adapt_order = %i\n", sconf->adapt_order); ff_dlog(avctx, "coef_table = %i\n", sconf->coef_table); ff_dlog(avctx, "long_term_prediction = %i\n", sconf->long_term_prediction); ff_dlog(avctx, "max_order = %i\n", sconf->max_order); ff_dlog(avctx, "block_switching = %i\n", sconf->block_switching); ff_dlog(avctx, "bgmc = %i\n", sconf->bgmc); ff_dlog(avctx, "sb_part = %i\n", sconf->sb_part); ff_dlog(avctx, "joint_stereo = %i\n", sconf->joint_stereo); ff_dlog(avctx, "mc_coding = %i\n", sconf->mc_coding); ff_dlog(avctx, "chan_config = %i\n", sconf->chan_config); ff_dlog(avctx, "chan_sort = %i\n", sconf->chan_sort); ff_dlog(avctx, "RLSLMS = %i\n", sconf->rlslms); ff_dlog(avctx, "chan_config_info = %i\n", sconf->chan_config_info); #endif } /** Read an ALSSpecificConfig from a buffer into the output struct. */ static av_cold int read_specific_config(ALSDecContext *ctx) { GetBitContext gb; uint64_t ht_size; int i, config_offset; MPEG4AudioConfig m4ac = {0}; ALSSpecificConfig *sconf = &ctx->sconf; AVCodecContext *avctx = ctx->avctx; uint32_t als_id, header_size, trailer_size; int ret; if ((ret = init_get_bits8(&gb, avctx->extradata, avctx->extradata_size)) < 0) return ret; config_offset = avpriv_mpeg4audio_get_config(&m4ac, avctx->extradata, avctx->extradata_size * 8, 1); if (config_offset < 0) return AVERROR_INVALIDDATA; skip_bits_long(&gb, config_offset); if (get_bits_left(&gb) < (30 << 3)) return AVERROR_INVALIDDATA; // read the fixed items als_id = get_bits_long(&gb, 32); avctx->sample_rate = m4ac.sample_rate; skip_bits_long(&gb, 32); // sample rate already known sconf->samples = get_bits_long(&gb, 32); avctx->channels = m4ac.channels; skip_bits(&gb, 16); // number of channels already known skip_bits(&gb, 3); // skip file_type sconf->resolution = get_bits(&gb, 3); sconf->floating = get_bits1(&gb); sconf->msb_first = get_bits1(&gb); sconf->frame_length = get_bits(&gb, 16) + 1; sconf->ra_distance = get_bits(&gb, 8); sconf->ra_flag = get_bits(&gb, 2); sconf->adapt_order = get_bits1(&gb); sconf->coef_table = get_bits(&gb, 2); sconf->long_term_prediction = get_bits1(&gb); sconf->max_order = get_bits(&gb, 10); sconf->block_switching = get_bits(&gb, 2); sconf->bgmc = get_bits1(&gb); sconf->sb_part = get_bits1(&gb); sconf->joint_stereo = get_bits1(&gb); sconf->mc_coding = get_bits1(&gb); sconf->chan_config = get_bits1(&gb); sconf->chan_sort = get_bits1(&gb); sconf->crc_enabled = get_bits1(&gb); sconf->rlslms = get_bits1(&gb); skip_bits(&gb, 5); // skip 5 reserved bits skip_bits1(&gb); // skip aux_data_enabled // check for ALSSpecificConfig struct if (als_id != MKBETAG('A','L','S','\0')) return AVERROR_INVALIDDATA; if (avctx->channels > FF_SANE_NB_CHANNELS) { avpriv_request_sample(avctx, "Huge number of channels\n"); return AVERROR_PATCHWELCOME; } ctx->cur_frame_length = sconf->frame_length; // read channel config if (sconf->chan_config) sconf->chan_config_info = get_bits(&gb, 16); // TODO: use this to set avctx->channel_layout // read channel sorting if (sconf->chan_sort && avctx->channels > 1) { int chan_pos_bits = av_ceil_log2(avctx->channels); int bits_needed = avctx->channels * chan_pos_bits + 7; if (get_bits_left(&gb) < bits_needed) return AVERROR_INVALIDDATA; if (!(sconf->chan_pos = av_malloc_array(avctx->channels, sizeof(*sconf->chan_pos)))) return AVERROR(ENOMEM); ctx->cs_switch = 1; for (i = 0; i < avctx->channels; i++) { sconf->chan_pos[i] = -1; } for (i = 0; i < avctx->channels; i++) { int idx; idx = get_bits(&gb, chan_pos_bits); if (idx >= avctx->channels || sconf->chan_pos[idx] != -1) { av_log(avctx, AV_LOG_WARNING, "Invalid channel reordering.\n"); ctx->cs_switch = 0; break; } sconf->chan_pos[idx] = i; } align_get_bits(&gb); } // read fixed header and trailer sizes, // if size = 0xFFFFFFFF then there is no data field! if (get_bits_left(&gb) < 64) return AVERROR_INVALIDDATA; header_size = get_bits_long(&gb, 32); trailer_size = get_bits_long(&gb, 32); if (header_size == 0xFFFFFFFF) header_size = 0; if (trailer_size == 0xFFFFFFFF) trailer_size = 0; ht_size = ((int64_t)(header_size) + (int64_t)(trailer_size)) << 3; // skip the header and trailer data if (get_bits_left(&gb) < ht_size) return AVERROR_INVALIDDATA; if (ht_size > INT32_MAX) return AVERROR_PATCHWELCOME; skip_bits_long(&gb, ht_size); // initialize CRC calculation if (sconf->crc_enabled) { if (get_bits_left(&gb) < 32) return AVERROR_INVALIDDATA; if (avctx->err_recognition & (AV_EF_CRCCHECK|AV_EF_CAREFUL)) { ctx->crc_table = av_crc_get_table(AV_CRC_32_IEEE_LE); ctx->crc = 0xFFFFFFFF; ctx->crc_org = ~get_bits_long(&gb, 32); } else skip_bits_long(&gb, 32); } // no need to read the rest of ALSSpecificConfig (ra_unit_size & aux data) dprint_specific_config(ctx); return 0; } /** Check the ALSSpecificConfig for unsupported features. */ static int check_specific_config(ALSDecContext *ctx) { ALSSpecificConfig *sconf = &ctx->sconf; int error = 0; // report unsupported feature and set error value #define MISSING_ERR(cond, str, errval) \ { \ if (cond) { \ avpriv_report_missing_feature(ctx->avctx, \ str); \ error = errval; \ } \ } MISSING_ERR(sconf->rlslms, "Adaptive RLS-LMS prediction", AVERROR_PATCHWELCOME); return error; } /** Parse the bs_info field to extract the block partitioning used in * block switching mode, refer to ISO/IEC 14496-3, section 11.6.2. */ static void parse_bs_info(const uint32_t bs_info, unsigned int n, unsigned int div, unsigned int **div_blocks, unsigned int *num_blocks) { if (n < 31 && ((bs_info << n) & 0x40000000)) { // if the level is valid and the investigated bit n is set // then recursively check both children at bits (2n+1) and (2n+2) n *= 2; div += 1; parse_bs_info(bs_info, n + 1, div, div_blocks, num_blocks); parse_bs_info(bs_info, n + 2, div, div_blocks, num_blocks); } else { // else the bit is not set or the last level has been reached // (bit implicitly not set) **div_blocks = div; (*div_blocks)++; (*num_blocks)++; } } /** Read and decode a Rice codeword. */ static int32_t decode_rice(GetBitContext *gb, unsigned int k) { int max = get_bits_left(gb) - k; unsigned q = get_unary(gb, 0, max); int r = k ? get_bits1(gb) : !(q & 1); if (k > 1) { q <<= (k - 1); q += get_bits_long(gb, k - 1); } else if (!k) { q >>= 1; } return r ? q : ~q; } /** Convert PARCOR coefficient k to direct filter coefficient. */ static void parcor_to_lpc(unsigned int k, const int32_t *par, int32_t *cof) { int i, j; for (i = 0, j = k - 1; i < j; i++, j--) { unsigned tmp1 = ((MUL64(par[k], cof[j]) + (1 << 19)) >> 20); cof[j] += ((MUL64(par[k], cof[i]) + (1 << 19)) >> 20); cof[i] += tmp1; } if (i == j) cof[i] += ((MUL64(par[k], cof[j]) + (1 << 19)) >> 20); cof[k] = par[k]; } /** Read block switching field if necessary and set actual block sizes. * Also assure that the block sizes of the last frame correspond to the * actual number of samples. */ static void get_block_sizes(ALSDecContext *ctx, unsigned int *div_blocks, uint32_t *bs_info) { ALSSpecificConfig *sconf = &ctx->sconf; GetBitContext *gb = &ctx->gb; unsigned int *ptr_div_blocks = div_blocks; unsigned int b; if (sconf->block_switching) { unsigned int bs_info_len = 1 << (sconf->block_switching + 2); *bs_info = get_bits_long(gb, bs_info_len); *bs_info <<= (32 - bs_info_len); } ctx->num_blocks = 0; parse_bs_info(*bs_info, 0, 0, &ptr_div_blocks, &ctx->num_blocks); // The last frame may have an overdetermined block structure given in // the bitstream. In that case the defined block structure would need // more samples than available to be consistent. // The block structure is actually used but the block sizes are adapted // to fit the actual number of available samples. // Example: 5 samples, 2nd level block sizes: 2 2 2 2. // This results in the actual block sizes: 2 2 1 0. // This is not specified in 14496-3 but actually done by the reference // codec RM22 revision 2. // This appears to happen in case of an odd number of samples in the last // frame which is actually not allowed by the block length switching part // of 14496-3. // The ALS conformance files feature an odd number of samples in the last // frame. for (b = 0; b < ctx->num_blocks; b++) div_blocks[b] = ctx->sconf.frame_length >> div_blocks[b]; if (ctx->cur_frame_length != ctx->sconf.frame_length) { unsigned int remaining = ctx->cur_frame_length; for (b = 0; b < ctx->num_blocks; b++) { if (remaining <= div_blocks[b]) { div_blocks[b] = remaining; ctx->num_blocks = b + 1; break; } remaining -= div_blocks[b]; } } } /** Read the block data for a constant block */ static int read_const_block_data(ALSDecContext *ctx, ALSBlockData *bd) { ALSSpecificConfig *sconf = &ctx->sconf; AVCodecContext *avctx = ctx->avctx; GetBitContext *gb = &ctx->gb; if (bd->block_length <= 0) return AVERROR_INVALIDDATA; *bd->raw_samples = 0; *bd->const_block = get_bits1(gb); // 1 = constant value, 0 = zero block (silence) bd->js_blocks = get_bits1(gb); // skip 5 reserved bits skip_bits(gb, 5); if (*bd->const_block) { unsigned int const_val_bits = sconf->floating ? 24 : avctx->bits_per_raw_sample; *bd->raw_samples = get_sbits_long(gb, const_val_bits); } // ensure constant block decoding by reusing this field *bd->const_block = 1; return 0; } /** Decode the block data for a constant block */ static void decode_const_block_data(ALSDecContext *ctx, ALSBlockData *bd) { int smp = bd->block_length - 1; int32_t val = *bd->raw_samples; int32_t *dst = bd->raw_samples + 1; // write raw samples into buffer for (; smp; smp--) *dst++ = val; } /** Read the block data for a non-constant block */ static int read_var_block_data(ALSDecContext *ctx, ALSBlockData *bd) { ALSSpecificConfig *sconf = &ctx->sconf; AVCodecContext *avctx = ctx->avctx; GetBitContext *gb = &ctx->gb; unsigned int k; unsigned int s[8]; unsigned int sx[8]; unsigned int sub_blocks, log2_sub_blocks, sb_length; unsigned int start = 0; unsigned int opt_order; int sb; int32_t *quant_cof = bd->quant_cof; int32_t *current_res; // ensure variable block decoding by reusing this field *bd->const_block = 0; *bd->opt_order = 1; bd->js_blocks = get_bits1(gb); opt_order = *bd->opt_order; // determine the number of subblocks for entropy decoding if (!sconf->bgmc && !sconf->sb_part) { log2_sub_blocks = 0; } else { if (sconf->bgmc && sconf->sb_part) log2_sub_blocks = get_bits(gb, 2); else log2_sub_blocks = 2 * get_bits1(gb); } sub_blocks = 1 << log2_sub_blocks; // do not continue in case of a damaged stream since // block_length must be evenly divisible by sub_blocks if (bd->block_length & (sub_blocks - 1) || bd->block_length <= 0) { av_log(avctx, AV_LOG_WARNING, "Block length is not evenly divisible by the number of subblocks.\n"); return AVERROR_INVALIDDATA; } sb_length = bd->block_length >> log2_sub_blocks; if (sconf->bgmc) { s[0] = get_bits(gb, 8 + (sconf->resolution > 1)); for (k = 1; k < sub_blocks; k++) s[k] = s[k - 1] + decode_rice(gb, 2); for (k = 0; k < sub_blocks; k++) { sx[k] = s[k] & 0x0F; s [k] >>= 4; } } else { s[0] = get_bits(gb, 4 + (sconf->resolution > 1)); for (k = 1; k < sub_blocks; k++) s[k] = s[k - 1] + decode_rice(gb, 0); } for (k = 1; k < sub_blocks; k++) if (s[k] > 32) { av_log(avctx, AV_LOG_ERROR, "k invalid for rice code.\n"); return AVERROR_INVALIDDATA; } if (get_bits1(gb)) *bd->shift_lsbs = get_bits(gb, 4) + 1; *bd->store_prev_samples = (bd->js_blocks && bd->raw_other) || *bd->shift_lsbs; if (!sconf->rlslms) { if (sconf->adapt_order && sconf->max_order) { int opt_order_length = av_ceil_log2(av_clip((bd->block_length >> 3) - 1, 2, sconf->max_order + 1)); *bd->opt_order = get_bits(gb, opt_order_length); if (*bd->opt_order > sconf->max_order) { *bd->opt_order = sconf->max_order; av_log(avctx, AV_LOG_ERROR, "Predictor order too large.\n"); return AVERROR_INVALIDDATA; } } else { *bd->opt_order = sconf->max_order; } opt_order = *bd->opt_order; if (opt_order) { int add_base; if (sconf->coef_table == 3) { add_base = 0x7F; // read coefficient 0 quant_cof[0] = 32 * parcor_scaled_values[get_bits(gb, 7)]; // read coefficient 1 if (opt_order > 1) quant_cof[1] = -32 * parcor_scaled_values[get_bits(gb, 7)]; // read coefficients 2 to opt_order for (k = 2; k < opt_order; k++) quant_cof[k] = get_bits(gb, 7); } else { int k_max; add_base = 1; // read coefficient 0 to 19 k_max = FFMIN(opt_order, 20); for (k = 0; k < k_max; k++) { int rice_param = parcor_rice_table[sconf->coef_table][k][1]; int offset = parcor_rice_table[sconf->coef_table][k][0]; quant_cof[k] = decode_rice(gb, rice_param) + offset; if (quant_cof[k] < -64 || quant_cof[k] > 63) { av_log(avctx, AV_LOG_ERROR, "quant_cof %"PRId32" is out of range.\n", quant_cof[k]); return AVERROR_INVALIDDATA; } } // read coefficients 20 to 126 k_max = FFMIN(opt_order, 127); for (; k < k_max; k++) quant_cof[k] = decode_rice(gb, 2) + (k & 1); // read coefficients 127 to opt_order for (; k < opt_order; k++) quant_cof[k] = decode_rice(gb, 1); quant_cof[0] = 32 * parcor_scaled_values[quant_cof[0] + 64]; if (opt_order > 1) quant_cof[1] = -32 * parcor_scaled_values[quant_cof[1] + 64]; } for (k = 2; k < opt_order; k++) quant_cof[k] = (quant_cof[k] * (1 << 14)) + (add_base << 13); } } // read LTP gain and lag values if (sconf->long_term_prediction) { *bd->use_ltp = get_bits1(gb); if (*bd->use_ltp) { int r, c; bd->ltp_gain[0] = decode_rice(gb, 1) * 8; bd->ltp_gain[1] = decode_rice(gb, 2) * 8; r = get_unary(gb, 0, 4); c = get_bits(gb, 2); if (r >= 4) { av_log(avctx, AV_LOG_ERROR, "r overflow\n"); return AVERROR_INVALIDDATA; } bd->ltp_gain[2] = ltp_gain_values[r][c]; bd->ltp_gain[3] = decode_rice(gb, 2) * 8; bd->ltp_gain[4] = decode_rice(gb, 1) * 8; *bd->ltp_lag = get_bits(gb, ctx->ltp_lag_length); *bd->ltp_lag += FFMAX(4, opt_order + 1); } } // read first value and residuals in case of a random access block if (bd->ra_block) { start = FFMIN(opt_order, 3); av_assert0(sb_length <= sconf->frame_length); if (sb_length <= start) { // opt_order or sb_length may be corrupted, either way this is unsupported and not well defined in the specification av_log(avctx, AV_LOG_ERROR, "Sub block length smaller or equal start\n"); return AVERROR_PATCHWELCOME; } if (opt_order) bd->raw_samples[0] = decode_rice(gb, avctx->bits_per_raw_sample - 4); if (opt_order > 1) bd->raw_samples[1] = decode_rice(gb, FFMIN(s[0] + 3, ctx->s_max)); if (opt_order > 2) bd->raw_samples[2] = decode_rice(gb, FFMIN(s[0] + 1, ctx->s_max)); } // read all residuals if (sconf->bgmc) { int delta[8]; unsigned int k [8]; unsigned int b = av_clip((av_ceil_log2(bd->block_length) - 3) >> 1, 0, 5); // read most significant bits unsigned int high; unsigned int low; unsigned int value; int ret = ff_bgmc_decode_init(gb, &high, &low, &value); if (ret < 0) return ret; current_res = bd->raw_samples + start; for (sb = 0; sb < sub_blocks; sb++) { unsigned int sb_len = sb_length - (sb ? 0 : start); k [sb] = s[sb] > b ? s[sb] - b : 0; delta[sb] = 5 - s[sb] + k[sb]; ff_bgmc_decode(gb, sb_len, current_res, delta[sb], sx[sb], &high, &low, &value, ctx->bgmc_lut, ctx->bgmc_lut_status); current_res += sb_len; } ff_bgmc_decode_end(gb); // read least significant bits and tails current_res = bd->raw_samples + start; for (sb = 0; sb < sub_blocks; sb++, start = 0) { unsigned int cur_tail_code = tail_code[sx[sb]][delta[sb]]; unsigned int cur_k = k[sb]; unsigned int cur_s = s[sb]; for (; start < sb_length; start++) { int32_t res = *current_res; if (res == cur_tail_code) { unsigned int max_msb = (2 + (sx[sb] > 2) + (sx[sb] > 10)) << (5 - delta[sb]); res = decode_rice(gb, cur_s); if (res >= 0) { res += (max_msb ) << cur_k; } else { res -= (max_msb - 1) << cur_k; } } else { if (res > cur_tail_code) res--; if (res & 1) res = -res; res >>= 1; if (cur_k) { res *= 1U << cur_k; res |= get_bits_long(gb, cur_k); } } *current_res++ = res; } } } else { current_res = bd->raw_samples + start; for (sb = 0; sb < sub_blocks; sb++, start = 0) for (; start < sb_length; start++) *current_res++ = decode_rice(gb, s[sb]); } return 0; } /** Decode the block data for a non-constant block */ static int decode_var_block_data(ALSDecContext *ctx, ALSBlockData *bd) { ALSSpecificConfig *sconf = &ctx->sconf; unsigned int block_length = bd->block_length; unsigned int smp = 0; unsigned int k; int opt_order = *bd->opt_order; int sb; int64_t y; int32_t *quant_cof = bd->quant_cof; int32_t *lpc_cof = bd->lpc_cof; int32_t *raw_samples = bd->raw_samples; int32_t *raw_samples_end = bd->raw_samples + bd->block_length; int32_t *lpc_cof_reversed = ctx->lpc_cof_reversed_buffer; // reverse long-term prediction if (*bd->use_ltp) { int ltp_smp; for (ltp_smp = FFMAX(*bd->ltp_lag - 2, 0); ltp_smp < block_length; ltp_smp++) { int center = ltp_smp - *bd->ltp_lag; int begin = FFMAX(0, center - 2); int end = center + 3; int tab = 5 - (end - begin); int base; y = 1 << 6; for (base = begin; base < end; base++, tab++) y += (uint64_t)MUL64(bd->ltp_gain[tab], raw_samples[base]); raw_samples[ltp_smp] += y >> 7; } } // reconstruct all samples from residuals if (bd->ra_block) { for (smp = 0; smp < FFMIN(opt_order, block_length); smp++) { y = 1 << 19; for (sb = 0; sb < smp; sb++) y += (uint64_t)MUL64(lpc_cof[sb], raw_samples[-(sb + 1)]); *raw_samples++ -= y >> 20; parcor_to_lpc(smp, quant_cof, lpc_cof); } } else { for (k = 0; k < opt_order; k++) parcor_to_lpc(k, quant_cof, lpc_cof); // store previous samples in case that they have to be altered if (*bd->store_prev_samples) memcpy(bd->prev_raw_samples, raw_samples - sconf->max_order, sizeof(*bd->prev_raw_samples) * sconf->max_order); // reconstruct difference signal for prediction (joint-stereo) if (bd->js_blocks && bd->raw_other) { uint32_t *left, *right; if (bd->raw_other > raw_samples) { // D = R - L left = raw_samples; right = bd->raw_other; } else { // D = R - L left = bd->raw_other; right = raw_samples; } for (sb = -1; sb >= -sconf->max_order; sb--) raw_samples[sb] = right[sb] - left[sb]; } // reconstruct shifted signal if (*bd->shift_lsbs) for (sb = -1; sb >= -sconf->max_order; sb--) raw_samples[sb] >>= *bd->shift_lsbs; } // reverse linear prediction coefficients for efficiency lpc_cof = lpc_cof + opt_order; for (sb = 0; sb < opt_order; sb++) lpc_cof_reversed[sb] = lpc_cof[-(sb + 1)]; // reconstruct raw samples raw_samples = bd->raw_samples + smp; lpc_cof = lpc_cof_reversed + opt_order; for (; raw_samples < raw_samples_end; raw_samples++) { y = 1 << 19; for (sb = -opt_order; sb < 0; sb++) y += (uint64_t)MUL64(lpc_cof[sb], raw_samples[sb]); *raw_samples -= y >> 20; } raw_samples = bd->raw_samples; // restore previous samples in case that they have been altered if (*bd->store_prev_samples) memcpy(raw_samples - sconf->max_order, bd->prev_raw_samples, sizeof(*raw_samples) * sconf->max_order); return 0; } /** Read the block data. */ static int read_block(ALSDecContext *ctx, ALSBlockData *bd) { int ret; GetBitContext *gb = &ctx->gb; ALSSpecificConfig *sconf = &ctx->sconf; *bd->shift_lsbs = 0; // read block type flag and read the samples accordingly if (get_bits1(gb)) { ret = read_var_block_data(ctx, bd); } else { ret = read_const_block_data(ctx, bd); } if (!sconf->mc_coding || ctx->js_switch) align_get_bits(gb); return ret; } /** Decode the block data. */ static int decode_block(ALSDecContext *ctx, ALSBlockData *bd) { unsigned int smp; int ret = 0; // read block type flag and read the samples accordingly if (*bd->const_block) decode_const_block_data(ctx, bd); else ret = decode_var_block_data(ctx, bd); // always return 0 if (ret < 0) return ret; // TODO: read RLSLMS extension data if (*bd->shift_lsbs) for (smp = 0; smp < bd->block_length; smp++) bd->raw_samples[smp] = (unsigned)bd->raw_samples[smp] << *bd->shift_lsbs; return 0; } /** Read and decode block data successively. */ static int read_decode_block(ALSDecContext *ctx, ALSBlockData *bd) { int ret; if ((ret = read_block(ctx, bd)) < 0) return ret; return decode_block(ctx, bd); } /** Compute the number of samples left to decode for the current frame and * sets these samples to zero. */ static void zero_remaining(unsigned int b, unsigned int b_max, const unsigned int *div_blocks, int32_t *buf) { unsigned int count = 0; while (b < b_max) count += div_blocks[b++]; if (count) memset(buf, 0, sizeof(*buf) * count); } /** Decode blocks independently. */ static int decode_blocks_ind(ALSDecContext *ctx, unsigned int ra_frame, unsigned int c, const unsigned int *div_blocks, unsigned int *js_blocks) { int ret; unsigned int b; ALSBlockData bd = { 0 }; bd.ra_block = ra_frame; bd.const_block = ctx->const_block; bd.shift_lsbs = ctx->shift_lsbs; bd.opt_order = ctx->opt_order; bd.store_prev_samples = ctx->store_prev_samples; bd.use_ltp = ctx->use_ltp; bd.ltp_lag = ctx->ltp_lag; bd.ltp_gain = ctx->ltp_gain[0]; bd.quant_cof = ctx->quant_cof[0]; bd.lpc_cof = ctx->lpc_cof[0]; bd.prev_raw_samples = ctx->prev_raw_samples; bd.raw_samples = ctx->raw_samples[c]; for (b = 0; b < ctx->num_blocks; b++) { bd.block_length = div_blocks[b]; if ((ret = read_decode_block(ctx, &bd)) < 0) { // damaged block, write zero for the rest of the frame zero_remaining(b, ctx->num_blocks, div_blocks, bd.raw_samples); return ret; } bd.raw_samples += div_blocks[b]; bd.ra_block = 0; } return 0; } /** Decode blocks dependently. */ static int decode_blocks(ALSDecContext *ctx, unsigned int ra_frame, unsigned int c, const unsigned int *div_blocks, unsigned int *js_blocks) { ALSSpecificConfig *sconf = &ctx->sconf; unsigned int offset = 0; unsigned int b; int ret; ALSBlockData bd[2] = { { 0 } }; bd[0].ra_block = ra_frame; bd[0].const_block = ctx->const_block; bd[0].shift_lsbs = ctx->shift_lsbs; bd[0].opt_order = ctx->opt_order; bd[0].store_prev_samples = ctx->store_prev_samples; bd[0].use_ltp = ctx->use_ltp; bd[0].ltp_lag = ctx->ltp_lag; bd[0].ltp_gain = ctx->ltp_gain[0]; bd[0].quant_cof = ctx->quant_cof[0]; bd[0].lpc_cof = ctx->lpc_cof[0]; bd[0].prev_raw_samples = ctx->prev_raw_samples; bd[0].js_blocks = *js_blocks; bd[1].ra_block = ra_frame; bd[1].const_block = ctx->const_block; bd[1].shift_lsbs = ctx->shift_lsbs; bd[1].opt_order = ctx->opt_order; bd[1].store_prev_samples = ctx->store_prev_samples; bd[1].use_ltp = ctx->use_ltp; bd[1].ltp_lag = ctx->ltp_lag; bd[1].ltp_gain = ctx->ltp_gain[0]; bd[1].quant_cof = ctx->quant_cof[0]; bd[1].lpc_cof = ctx->lpc_cof[0]; bd[1].prev_raw_samples = ctx->prev_raw_samples; bd[1].js_blocks = *(js_blocks + 1); // decode all blocks for (b = 0; b < ctx->num_blocks; b++) { unsigned int s; bd[0].block_length = div_blocks[b]; bd[1].block_length = div_blocks[b]; bd[0].raw_samples = ctx->raw_samples[c ] + offset; bd[1].raw_samples = ctx->raw_samples[c + 1] + offset; bd[0].raw_other = bd[1].raw_samples; bd[1].raw_other = bd[0].raw_samples; if ((ret = read_decode_block(ctx, &bd[0])) < 0 || (ret = read_decode_block(ctx, &bd[1])) < 0) goto fail; // reconstruct joint-stereo blocks if (bd[0].js_blocks) { if (bd[1].js_blocks) av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel pair.\n"); for (s = 0; s < div_blocks[b]; s++) bd[0].raw_samples[s] = bd[1].raw_samples[s] - (unsigned)bd[0].raw_samples[s]; } else if (bd[1].js_blocks) { for (s = 0; s < div_blocks[b]; s++) bd[1].raw_samples[s] = bd[1].raw_samples[s] + (unsigned)bd[0].raw_samples[s]; } offset += div_blocks[b]; bd[0].ra_block = 0; bd[1].ra_block = 0; } // store carryover raw samples, // the others channel raw samples are stored by the calling function. memmove(ctx->raw_samples[c] - sconf->max_order, ctx->raw_samples[c] - sconf->max_order + sconf->frame_length, sizeof(*ctx->raw_samples[c]) * sconf->max_order); return 0; fail: // damaged block, write zero for the rest of the frame zero_remaining(b, ctx->num_blocks, div_blocks, bd[0].raw_samples); zero_remaining(b, ctx->num_blocks, div_blocks, bd[1].raw_samples); return ret; } static inline int als_weighting(GetBitContext *gb, int k, int off) { int idx = av_clip(decode_rice(gb, k) + off, 0, FF_ARRAY_ELEMS(mcc_weightings) - 1); return mcc_weightings[idx]; } /** Read the channel data. */ static int read_channel_data(ALSDecContext *ctx, ALSChannelData *cd, int c) { GetBitContext *gb = &ctx->gb; ALSChannelData *current = cd; unsigned int channels = ctx->avctx->channels; int entries = 0; while (entries < channels && !(current->stop_flag = get_bits1(gb))) { current->master_channel = get_bits_long(gb, av_ceil_log2(channels)); if (current->master_channel >= channels) { av_log(ctx->avctx, AV_LOG_ERROR, "Invalid master channel.\n"); return AVERROR_INVALIDDATA; } if (current->master_channel != c) { current->time_diff_flag = get_bits1(gb); current->weighting[0] = als_weighting(gb, 1, 16); current->weighting[1] = als_weighting(gb, 2, 14); current->weighting[2] = als_weighting(gb, 1, 16); if (current->time_diff_flag) { current->weighting[3] = als_weighting(gb, 1, 16); current->weighting[4] = als_weighting(gb, 1, 16); current->weighting[5] = als_weighting(gb, 1, 16); current->time_diff_sign = get_bits1(gb); current->time_diff_index = get_bits(gb, ctx->ltp_lag_length - 3) + 3; } } current++; entries++; } if (entries == channels) { av_log(ctx->avctx, AV_LOG_ERROR, "Damaged channel data.\n"); return AVERROR_INVALIDDATA; } align_get_bits(gb); return 0; } /** Recursively reverts the inter-channel correlation for a block. */ static int revert_channel_correlation(ALSDecContext *ctx, ALSBlockData *bd, ALSChannelData **cd, int *reverted, unsigned int offset, int c) { ALSChannelData *ch = cd[c]; unsigned int dep = 0; unsigned int channels = ctx->avctx->channels; unsigned int channel_size = ctx->sconf.frame_length + ctx->sconf.max_order; if (reverted[c]) return 0; reverted[c] = 1; while (dep < channels && !ch[dep].stop_flag) { revert_channel_correlation(ctx, bd, cd, reverted, offset, ch[dep].master_channel); dep++; } if (dep == channels) { av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel correlation.\n"); return AVERROR_INVALIDDATA; } bd->const_block = ctx->const_block + c; bd->shift_lsbs = ctx->shift_lsbs + c; bd->opt_order = ctx->opt_order + c; bd->store_prev_samples = ctx->store_prev_samples + c; bd->use_ltp = ctx->use_ltp + c; bd->ltp_lag = ctx->ltp_lag + c; bd->ltp_gain = ctx->ltp_gain[c]; bd->lpc_cof = ctx->lpc_cof[c]; bd->quant_cof = ctx->quant_cof[c]; bd->raw_samples = ctx->raw_samples[c] + offset; for (dep = 0; !ch[dep].stop_flag; dep++) { ptrdiff_t smp; ptrdiff_t begin = 1; ptrdiff_t end = bd->block_length - 1; int64_t y; int32_t *master = ctx->raw_samples[ch[dep].master_channel] + offset; if (ch[dep].master_channel == c) continue; if (ch[dep].time_diff_flag) { int t = ch[dep].time_diff_index; if (ch[dep].time_diff_sign) { t = -t; if (begin < t) { av_log(ctx->avctx, AV_LOG_ERROR, "begin %"PTRDIFF_SPECIFIER" smaller than time diff index %d.\n", begin, t); return AVERROR_INVALIDDATA; } begin -= t; } else { if (end < t) { av_log(ctx->avctx, AV_LOG_ERROR, "end %"PTRDIFF_SPECIFIER" smaller than time diff index %d.\n", end, t); return AVERROR_INVALIDDATA; } end -= t; } if (FFMIN(begin - 1, begin - 1 + t) < ctx->raw_buffer - master || FFMAX(end + 1, end + 1 + t) > ctx->raw_buffer + channels * channel_size - master) { av_log(ctx->avctx, AV_LOG_ERROR, "sample pointer range [%p, %p] not contained in raw_buffer [%p, %p].\n", master + FFMIN(begin - 1, begin - 1 + t), master + FFMAX(end + 1, end + 1 + t), ctx->raw_buffer, ctx->raw_buffer + channels * channel_size); return AVERROR_INVALIDDATA; } for (smp = begin; smp < end; smp++) { y = (1 << 6) + MUL64(ch[dep].weighting[0], master[smp - 1 ]) + MUL64(ch[dep].weighting[1], master[smp ]) + MUL64(ch[dep].weighting[2], master[smp + 1 ]) + MUL64(ch[dep].weighting[3], master[smp - 1 + t]) + MUL64(ch[dep].weighting[4], master[smp + t]) + MUL64(ch[dep].weighting[5], master[smp + 1 + t]); bd->raw_samples[smp] += y >> 7; } } else { if (begin - 1 < ctx->raw_buffer - master || end + 1 > ctx->raw_buffer + channels * channel_size - master) { av_log(ctx->avctx, AV_LOG_ERROR, "sample pointer range [%p, %p] not contained in raw_buffer [%p, %p].\n", master + begin - 1, master + end + 1, ctx->raw_buffer, ctx->raw_buffer + channels * channel_size); return AVERROR_INVALIDDATA; } for (smp = begin; smp < end; smp++) { y = (1 << 6) + MUL64(ch[dep].weighting[0], master[smp - 1]) + MUL64(ch[dep].weighting[1], master[smp ]) + MUL64(ch[dep].weighting[2], master[smp + 1]); bd->raw_samples[smp] += y >> 7; } } } return 0; } /** multiply two softfloats and handle the rounding off */ static SoftFloat_IEEE754 multiply(SoftFloat_IEEE754 a, SoftFloat_IEEE754 b) { uint64_t mantissa_temp; uint64_t mask_64; int cutoff_bit_count; unsigned char last_2_bits; unsigned int mantissa; int32_t sign; uint32_t return_val = 0; int bit_count = 48; sign = a.sign ^ b.sign; // Multiply mantissa bits in a 64-bit register mantissa_temp = (uint64_t)a.mant * (uint64_t)b.mant; mask_64 = (uint64_t)0x1 << 47; if (!mantissa_temp) return FLOAT_0; // Count the valid bit count while (!(mantissa_temp & mask_64) && mask_64) { bit_count--; mask_64 >>= 1; } // Round off cutoff_bit_count = bit_count - 24; if (cutoff_bit_count > 0) { last_2_bits = (unsigned char)(((unsigned int)mantissa_temp >> (cutoff_bit_count - 1)) & 0x3 ); if ((last_2_bits == 0x3) || ((last_2_bits == 0x1) && ((unsigned int)mantissa_temp & ((0x1UL << (cutoff_bit_count - 1)) - 1)))) { // Need to round up mantissa_temp += (uint64_t)0x1 << cutoff_bit_count; } } if (cutoff_bit_count >= 0) { mantissa = (unsigned int)(mantissa_temp >> cutoff_bit_count); } else { mantissa = (unsigned int)(mantissa_temp <<-cutoff_bit_count); } // Need one more shift? if (mantissa & 0x01000000ul) { bit_count++; mantissa >>= 1; } if (!sign) { return_val = 0x80000000U; } return_val |= ((unsigned)av_clip(a.exp + b.exp + bit_count - 47, -126, 127) << 23) & 0x7F800000; return_val |= mantissa; return av_bits2sf_ieee754(return_val); } /** Read and decode the floating point sample data */ static int read_diff_float_data(ALSDecContext *ctx, unsigned int ra_frame) { AVCodecContext *avctx = ctx->avctx; GetBitContext *gb = &ctx->gb; SoftFloat_IEEE754 *acf = ctx->acf; int *shift_value = ctx->shift_value; int *last_shift_value = ctx->last_shift_value; int *last_acf_mantissa = ctx->last_acf_mantissa; int **raw_mantissa = ctx->raw_mantissa; int *nbits = ctx->nbits; unsigned char *larray = ctx->larray; int frame_length = ctx->cur_frame_length; SoftFloat_IEEE754 scale = av_int2sf_ieee754(0x1u, 23); unsigned int partA_flag; unsigned int highest_byte; unsigned int shift_amp; uint32_t tmp_32; int use_acf; int nchars; int i; int c; long k; long nbits_aligned; unsigned long acc; unsigned long j; uint32_t sign; uint32_t e; uint32_t mantissa; skip_bits_long(gb, 32); //num_bytes_diff_float use_acf = get_bits1(gb); if (ra_frame) { memset(last_acf_mantissa, 0, avctx->channels * sizeof(*last_acf_mantissa)); memset(last_shift_value, 0, avctx->channels * sizeof(*last_shift_value) ); ff_mlz_flush_dict(ctx->mlz); } for (c = 0; c < avctx->channels; ++c) { if (use_acf) { //acf_flag if (get_bits1(gb)) { tmp_32 = get_bits(gb, 23); last_acf_mantissa[c] = tmp_32; } else { tmp_32 = last_acf_mantissa[c]; } acf[c] = av_bits2sf_ieee754(tmp_32); } else { acf[c] = FLOAT_1; } highest_byte = get_bits(gb, 2); partA_flag = get_bits1(gb); shift_amp = get_bits1(gb); if (shift_amp) { shift_value[c] = get_bits(gb, 8); last_shift_value[c] = shift_value[c]; } else { shift_value[c] = last_shift_value[c]; } if (partA_flag) { if (!get_bits1(gb)) { //uncompressed for (i = 0; i < frame_length; ++i) { if (ctx->raw_samples[c][i] == 0) { ctx->raw_mantissa[c][i] = get_bits_long(gb, 32); } } } else { //compressed nchars = 0; for (i = 0; i < frame_length; ++i) { if (ctx->raw_samples[c][i] == 0) { nchars += 4; } } tmp_32 = ff_mlz_decompression(ctx->mlz, gb, nchars, larray); if(tmp_32 != nchars) { av_log(ctx->avctx, AV_LOG_ERROR, "Error in MLZ decompression (%"PRId32", %d).\n", tmp_32, nchars); return AVERROR_INVALIDDATA; } for (i = 0; i < frame_length; ++i) { ctx->raw_mantissa[c][i] = AV_RB32(larray); } } } //decode part B if (highest_byte) { for (i = 0; i < frame_length; ++i) { if (ctx->raw_samples[c][i] != 0) { //The following logic is taken from Tabel 14.45 and 14.46 from the ISO spec if (av_cmp_sf_ieee754(acf[c], FLOAT_1)) { nbits[i] = 23 - av_log2(abs(ctx->raw_samples[c][i])); } else { nbits[i] = 23; } nbits[i] = FFMIN(nbits[i], highest_byte*8); } } if (!get_bits1(gb)) { //uncompressed for (i = 0; i < frame_length; ++i) { if (ctx->raw_samples[c][i] != 0) { raw_mantissa[c][i] = get_bitsz(gb, nbits[i]); } } } else { //compressed nchars = 0; for (i = 0; i < frame_length; ++i) { if (ctx->raw_samples[c][i]) { nchars += (int) nbits[i] / 8; if (nbits[i] & 7) { ++nchars; } } } tmp_32 = ff_mlz_decompression(ctx->mlz, gb, nchars, larray); if(tmp_32 != nchars) { av_log(ctx->avctx, AV_LOG_ERROR, "Error in MLZ decompression (%"PRId32", %d).\n", tmp_32, nchars); return AVERROR_INVALIDDATA; } j = 0; for (i = 0; i < frame_length; ++i) { if (ctx->raw_samples[c][i]) { if (nbits[i] & 7) { nbits_aligned = 8 * ((unsigned int)(nbits[i] / 8) + 1); } else { nbits_aligned = nbits[i]; } acc = 0; for (k = 0; k < nbits_aligned/8; ++k) { acc = (acc << 8) + larray[j++]; } acc >>= (nbits_aligned - nbits[i]); raw_mantissa[c][i] = acc; } } } } for (i = 0; i < frame_length; ++i) { SoftFloat_IEEE754 pcm_sf = av_int2sf_ieee754(ctx->raw_samples[c][i], 0); pcm_sf = av_div_sf_ieee754(pcm_sf, scale); if (ctx->raw_samples[c][i] != 0) { if (!av_cmp_sf_ieee754(acf[c], FLOAT_1)) { pcm_sf = multiply(acf[c], pcm_sf); } sign = pcm_sf.sign; e = pcm_sf.exp; mantissa = (pcm_sf.mant | 0x800000) + raw_mantissa[c][i]; while(mantissa >= 0x1000000) { e++; mantissa >>= 1; } if (mantissa) e += (shift_value[c] - 127); mantissa &= 0x007fffffUL; tmp_32 = (sign << 31) | ((e + EXP_BIAS) << 23) | (mantissa); ctx->raw_samples[c][i] = tmp_32; } else { ctx->raw_samples[c][i] = raw_mantissa[c][i] & 0x007fffffUL; } } align_get_bits(gb); } return 0; } /** Read the frame data. */ static int read_frame_data(ALSDecContext *ctx, unsigned int ra_frame) { ALSSpecificConfig *sconf = &ctx->sconf; AVCodecContext *avctx = ctx->avctx; GetBitContext *gb = &ctx->gb; unsigned int div_blocks[32]; ///< block sizes. unsigned int c; unsigned int js_blocks[2]; uint32_t bs_info = 0; int ret; // skip the size of the ra unit if present in the frame if (sconf->ra_flag == RA_FLAG_FRAMES && ra_frame) skip_bits_long(gb, 32); if (sconf->mc_coding && sconf->joint_stereo) { ctx->js_switch = get_bits1(gb); align_get_bits(gb); } if (!sconf->mc_coding || ctx->js_switch) { int independent_bs = !sconf->joint_stereo; for (c = 0; c < avctx->channels; c++) { js_blocks[0] = 0; js_blocks[1] = 0; get_block_sizes(ctx, div_blocks, &bs_info); // if joint_stereo and block_switching is set, independent decoding // is signaled via the first bit of bs_info if (sconf->joint_stereo && sconf->block_switching) if (bs_info >> 31) independent_bs = 2; // if this is the last channel, it has to be decoded independently if (c == avctx->channels - 1 || (c & 1)) independent_bs = 1; if (independent_bs) { ret = decode_blocks_ind(ctx, ra_frame, c, div_blocks, js_blocks); if (ret < 0) return ret; independent_bs--; } else { ret = decode_blocks(ctx, ra_frame, c, div_blocks, js_blocks); if (ret < 0) return ret; c++; } // store carryover raw samples memmove(ctx->raw_samples[c] - sconf->max_order, ctx->raw_samples[c] - sconf->max_order + sconf->frame_length, sizeof(*ctx->raw_samples[c]) * sconf->max_order); } } else { // multi-channel coding ALSBlockData bd = { 0 }; int b, ret; int *reverted_channels = ctx->reverted_channels; unsigned int offset = 0; for (c = 0; c < avctx->channels; c++) if (ctx->chan_data[c] < ctx->chan_data_buffer) { av_log(ctx->avctx, AV_LOG_ERROR, "Invalid channel data.\n"); return AVERROR_INVALIDDATA; } memset(reverted_channels, 0, sizeof(*reverted_channels) * avctx->channels); bd.ra_block = ra_frame; bd.prev_raw_samples = ctx->prev_raw_samples; get_block_sizes(ctx, div_blocks, &bs_info); for (b = 0; b < ctx->num_blocks; b++) { bd.block_length = div_blocks[b]; if (bd.block_length <= 0) { av_log(ctx->avctx, AV_LOG_WARNING, "Invalid block length %u in channel data!\n", bd.block_length); continue; } for (c = 0; c < avctx->channels; c++) { bd.const_block = ctx->const_block + c; bd.shift_lsbs = ctx->shift_lsbs + c; bd.opt_order = ctx->opt_order + c; bd.store_prev_samples = ctx->store_prev_samples + c; bd.use_ltp = ctx->use_ltp + c; bd.ltp_lag = ctx->ltp_lag + c; bd.ltp_gain = ctx->ltp_gain[c]; bd.lpc_cof = ctx->lpc_cof[c]; bd.quant_cof = ctx->quant_cof[c]; bd.raw_samples = ctx->raw_samples[c] + offset; bd.raw_other = NULL; if ((ret = read_block(ctx, &bd)) < 0) return ret; if ((ret = read_channel_data(ctx, ctx->chan_data[c], c)) < 0) return ret; } for (c = 0; c < avctx->channels; c++) { ret = revert_channel_correlation(ctx, &bd, ctx->chan_data, reverted_channels, offset, c); if (ret < 0) return ret; } for (c = 0; c < avctx->channels; c++) { bd.const_block = ctx->const_block + c; bd.shift_lsbs = ctx->shift_lsbs + c; bd.opt_order = ctx->opt_order + c; bd.store_prev_samples = ctx->store_prev_samples + c; bd.use_ltp = ctx->use_ltp + c; bd.ltp_lag = ctx->ltp_lag + c; bd.ltp_gain = ctx->ltp_gain[c]; bd.lpc_cof = ctx->lpc_cof[c]; bd.quant_cof = ctx->quant_cof[c]; bd.raw_samples = ctx->raw_samples[c] + offset; if ((ret = decode_block(ctx, &bd)) < 0) return ret; } memset(reverted_channels, 0, avctx->channels * sizeof(*reverted_channels)); offset += div_blocks[b]; bd.ra_block = 0; } // store carryover raw samples for (c = 0; c < avctx->channels; c++) memmove(ctx->raw_samples[c] - sconf->max_order, ctx->raw_samples[c] - sconf->max_order + sconf->frame_length, sizeof(*ctx->raw_samples[c]) * sconf->max_order); } if (sconf->floating) { read_diff_float_data(ctx, ra_frame); } if (get_bits_left(gb) < 0) { av_log(ctx->avctx, AV_LOG_ERROR, "Overread %d\n", -get_bits_left(gb)); return AVERROR_INVALIDDATA; } return 0; } /** Decode an ALS frame. */ static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr, AVPacket *avpkt) { ALSDecContext *ctx = avctx->priv_data; AVFrame *frame = data; ALSSpecificConfig *sconf = &ctx->sconf; const uint8_t *buffer = avpkt->data; int buffer_size = avpkt->size; int invalid_frame, ret; unsigned int c, sample, ra_frame, bytes_read, shift; if ((ret = init_get_bits8(&ctx->gb, buffer, buffer_size)) < 0) return ret; // In the case that the distance between random access frames is set to zero // (sconf->ra_distance == 0) no frame is treated as a random access frame. // For the first frame, if prediction is used, all samples used from the // previous frame are assumed to be zero. ra_frame = sconf->ra_distance && !(ctx->frame_id % sconf->ra_distance); // the last frame to decode might have a different length if (sconf->samples != 0xFFFFFFFF) ctx->cur_frame_length = FFMIN(sconf->samples - ctx->frame_id * (uint64_t) sconf->frame_length, sconf->frame_length); else ctx->cur_frame_length = sconf->frame_length; // decode the frame data if ((invalid_frame = read_frame_data(ctx, ra_frame)) < 0) av_log(ctx->avctx, AV_LOG_WARNING, "Reading frame data failed. Skipping RA unit.\n"); ctx->frame_id++; /* get output buffer */ frame->nb_samples = ctx->cur_frame_length; if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) return ret; // transform decoded frame into output format #define INTERLEAVE_OUTPUT(bps) \ { \ int##bps##_t *dest = (int##bps##_t*)frame->data[0]; \ shift = bps - ctx->avctx->bits_per_raw_sample; \ if (!ctx->cs_switch) { \ for (sample = 0; sample < ctx->cur_frame_length; sample++) \ for (c = 0; c < avctx->channels; c++) \ *dest++ = ctx->raw_samples[c][sample] * (1U << shift); \ } else { \ for (sample = 0; sample < ctx->cur_frame_length; sample++) \ for (c = 0; c < avctx->channels; c++) \ *dest++ = ctx->raw_samples[sconf->chan_pos[c]][sample] * (1U << shift); \ } \ } if (ctx->avctx->bits_per_raw_sample <= 16) { INTERLEAVE_OUTPUT(16) } else { INTERLEAVE_OUTPUT(32) } // update CRC if (sconf->crc_enabled && (avctx->err_recognition & (AV_EF_CRCCHECK|AV_EF_CAREFUL))) { int swap = HAVE_BIGENDIAN != sconf->msb_first; if (ctx->avctx->bits_per_raw_sample == 24) { int32_t *src = (int32_t *)frame->data[0]; for (sample = 0; sample < ctx->cur_frame_length * avctx->channels; sample++) { int32_t v; if (swap) v = av_bswap32(src[sample]); else v = src[sample]; if (!HAVE_BIGENDIAN) v >>= 8; ctx->crc = av_crc(ctx->crc_table, ctx->crc, (uint8_t*)(&v), 3); } } else { uint8_t *crc_source; if (swap) { if (ctx->avctx->bits_per_raw_sample <= 16) { int16_t *src = (int16_t*) frame->data[0]; int16_t *dest = (int16_t*) ctx->crc_buffer; for (sample = 0; sample < ctx->cur_frame_length * avctx->channels; sample++) *dest++ = av_bswap16(src[sample]); } else { ctx->bdsp.bswap_buf((uint32_t *) ctx->crc_buffer, (uint32_t *) frame->data[0], ctx->cur_frame_length * avctx->channels); } crc_source = ctx->crc_buffer; } else { crc_source = frame->data[0]; } ctx->crc = av_crc(ctx->crc_table, ctx->crc, crc_source, ctx->cur_frame_length * avctx->channels * av_get_bytes_per_sample(avctx->sample_fmt)); } // check CRC sums if this is the last frame if (ctx->cur_frame_length != sconf->frame_length && ctx->crc_org != ctx->crc) { av_log(avctx, AV_LOG_ERROR, "CRC error.\n"); if (avctx->err_recognition & AV_EF_EXPLODE) return AVERROR_INVALIDDATA; } } *got_frame_ptr = 1; bytes_read = invalid_frame ? buffer_size : (get_bits_count(&ctx->gb) + 7) >> 3; return bytes_read; } /** Uninitialize the ALS decoder. */ static av_cold int decode_end(AVCodecContext *avctx) { ALSDecContext *ctx = avctx->priv_data; int i; av_freep(&ctx->sconf.chan_pos); ff_bgmc_end(&ctx->bgmc_lut, &ctx->bgmc_lut_status); av_freep(&ctx->const_block); av_freep(&ctx->shift_lsbs); av_freep(&ctx->opt_order); av_freep(&ctx->store_prev_samples); av_freep(&ctx->use_ltp); av_freep(&ctx->ltp_lag); av_freep(&ctx->ltp_gain); av_freep(&ctx->ltp_gain_buffer); av_freep(&ctx->quant_cof); av_freep(&ctx->lpc_cof); av_freep(&ctx->quant_cof_buffer); av_freep(&ctx->lpc_cof_buffer); av_freep(&ctx->lpc_cof_reversed_buffer); av_freep(&ctx->prev_raw_samples); av_freep(&ctx->raw_samples); av_freep(&ctx->raw_buffer); av_freep(&ctx->chan_data); av_freep(&ctx->chan_data_buffer); av_freep(&ctx->reverted_channels); av_freep(&ctx->crc_buffer); if (ctx->mlz) { av_freep(&ctx->mlz->dict); av_freep(&ctx->mlz); } av_freep(&ctx->acf); av_freep(&ctx->last_acf_mantissa); av_freep(&ctx->shift_value); av_freep(&ctx->last_shift_value); if (ctx->raw_mantissa) { for (i = 0; i < avctx->channels; i++) { av_freep(&ctx->raw_mantissa[i]); } av_freep(&ctx->raw_mantissa); } av_freep(&ctx->larray); av_freep(&ctx->nbits); return 0; } /** Initialize the ALS decoder. */ static av_cold int decode_init(AVCodecContext *avctx) { unsigned int c; unsigned int channel_size; int num_buffers, ret; ALSDecContext *ctx = avctx->priv_data; ALSSpecificConfig *sconf = &ctx->sconf; ctx->avctx = avctx; if (!avctx->extradata) { av_log(avctx, AV_LOG_ERROR, "Missing required ALS extradata.\n"); return AVERROR_INVALIDDATA; } if ((ret = read_specific_config(ctx)) < 0) { av_log(avctx, AV_LOG_ERROR, "Reading ALSSpecificConfig failed.\n"); goto fail; } if ((ret = check_specific_config(ctx)) < 0) { goto fail; } if (sconf->bgmc) { ret = ff_bgmc_init(avctx, &ctx->bgmc_lut, &ctx->bgmc_lut_status); if (ret < 0) goto fail; } if (sconf->floating) { avctx->sample_fmt = AV_SAMPLE_FMT_FLT; avctx->bits_per_raw_sample = 32; } else { avctx->sample_fmt = sconf->resolution > 1 ? AV_SAMPLE_FMT_S32 : AV_SAMPLE_FMT_S16; avctx->bits_per_raw_sample = (sconf->resolution + 1) * 8; if (avctx->bits_per_raw_sample > 32) { av_log(avctx, AV_LOG_ERROR, "Bits per raw sample %d larger than 32.\n", avctx->bits_per_raw_sample); ret = AVERROR_INVALIDDATA; goto fail; } } // set maximum Rice parameter for progressive decoding based on resolution // This is not specified in 14496-3 but actually done by the reference // codec RM22 revision 2. ctx->s_max = sconf->resolution > 1 ? 31 : 15; // set lag value for long-term prediction ctx->ltp_lag_length = 8 + (avctx->sample_rate >= 96000) + (avctx->sample_rate >= 192000); // allocate quantized parcor coefficient buffer num_buffers = sconf->mc_coding ? avctx->channels : 1; if (num_buffers * (uint64_t)num_buffers > INT_MAX) // protect chan_data_buffer allocation return AVERROR_INVALIDDATA; ctx->quant_cof = av_malloc_array(num_buffers, sizeof(*ctx->quant_cof)); ctx->lpc_cof = av_malloc_array(num_buffers, sizeof(*ctx->lpc_cof)); ctx->quant_cof_buffer = av_malloc_array(num_buffers * sconf->max_order, sizeof(*ctx->quant_cof_buffer)); ctx->lpc_cof_buffer = av_malloc_array(num_buffers * sconf->max_order, sizeof(*ctx->lpc_cof_buffer)); ctx->lpc_cof_reversed_buffer = av_malloc_array(sconf->max_order, sizeof(*ctx->lpc_cof_buffer)); if (!ctx->quant_cof || !ctx->lpc_cof || !ctx->quant_cof_buffer || !ctx->lpc_cof_buffer || !ctx->lpc_cof_reversed_buffer) { av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n"); ret = AVERROR(ENOMEM); goto fail; } // assign quantized parcor coefficient buffers for (c = 0; c < num_buffers; c++) { ctx->quant_cof[c] = ctx->quant_cof_buffer + c * sconf->max_order; ctx->lpc_cof[c] = ctx->lpc_cof_buffer + c * sconf->max_order; } // allocate and assign lag and gain data buffer for ltp mode ctx->const_block = av_malloc_array(num_buffers, sizeof(*ctx->const_block)); ctx->shift_lsbs = av_malloc_array(num_buffers, sizeof(*ctx->shift_lsbs)); ctx->opt_order = av_malloc_array(num_buffers, sizeof(*ctx->opt_order)); ctx->store_prev_samples = av_malloc_array(num_buffers, sizeof(*ctx->store_prev_samples)); ctx->use_ltp = av_mallocz_array(num_buffers, sizeof(*ctx->use_ltp)); ctx->ltp_lag = av_malloc_array(num_buffers, sizeof(*ctx->ltp_lag)); ctx->ltp_gain = av_malloc_array(num_buffers, sizeof(*ctx->ltp_gain)); ctx->ltp_gain_buffer = av_malloc_array(num_buffers * 5, sizeof(*ctx->ltp_gain_buffer)); if (!ctx->const_block || !ctx->shift_lsbs || !ctx->opt_order || !ctx->store_prev_samples || !ctx->use_ltp || !ctx->ltp_lag || !ctx->ltp_gain || !ctx->ltp_gain_buffer) { av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n"); ret = AVERROR(ENOMEM); goto fail; } for (c = 0; c < num_buffers; c++) ctx->ltp_gain[c] = ctx->ltp_gain_buffer + c * 5; // allocate and assign channel data buffer for mcc mode if (sconf->mc_coding) { ctx->chan_data_buffer = av_mallocz_array(num_buffers * num_buffers, sizeof(*ctx->chan_data_buffer)); ctx->chan_data = av_mallocz_array(num_buffers, sizeof(*ctx->chan_data)); ctx->reverted_channels = av_malloc_array(num_buffers, sizeof(*ctx->reverted_channels)); if (!ctx->chan_data_buffer || !ctx->chan_data || !ctx->reverted_channels) { av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n"); ret = AVERROR(ENOMEM); goto fail; } for (c = 0; c < num_buffers; c++) ctx->chan_data[c] = ctx->chan_data_buffer + c * num_buffers; } else { ctx->chan_data = NULL; ctx->chan_data_buffer = NULL; ctx->reverted_channels = NULL; } channel_size = sconf->frame_length + sconf->max_order; ctx->prev_raw_samples = av_malloc_array(sconf->max_order, sizeof(*ctx->prev_raw_samples)); ctx->raw_buffer = av_mallocz_array(avctx->channels * channel_size, sizeof(*ctx->raw_buffer)); ctx->raw_samples = av_malloc_array(avctx->channels, sizeof(*ctx->raw_samples)); if (sconf->floating) { ctx->acf = av_malloc_array(avctx->channels, sizeof(*ctx->acf)); ctx->shift_value = av_malloc_array(avctx->channels, sizeof(*ctx->shift_value)); ctx->last_shift_value = av_malloc_array(avctx->channels, sizeof(*ctx->last_shift_value)); ctx->last_acf_mantissa = av_malloc_array(avctx->channels, sizeof(*ctx->last_acf_mantissa)); ctx->raw_mantissa = av_mallocz_array(avctx->channels, sizeof(*ctx->raw_mantissa)); ctx->larray = av_malloc_array(ctx->cur_frame_length * 4, sizeof(*ctx->larray)); ctx->nbits = av_malloc_array(ctx->cur_frame_length, sizeof(*ctx->nbits)); ctx->mlz = av_mallocz(sizeof(*ctx->mlz)); if (!ctx->mlz || !ctx->acf || !ctx->shift_value || !ctx->last_shift_value || !ctx->last_acf_mantissa || !ctx->raw_mantissa) { av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n"); ret = AVERROR(ENOMEM); goto fail; } ff_mlz_init_dict(avctx, ctx->mlz); ff_mlz_flush_dict(ctx->mlz); for (c = 0; c < avctx->channels; ++c) { ctx->raw_mantissa[c] = av_mallocz_array(ctx->cur_frame_length, sizeof(**ctx->raw_mantissa)); } } // allocate previous raw sample buffer if (!ctx->prev_raw_samples || !ctx->raw_buffer|| !ctx->raw_samples) { av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n"); ret = AVERROR(ENOMEM); goto fail; } // assign raw samples buffers ctx->raw_samples[0] = ctx->raw_buffer + sconf->max_order; for (c = 1; c < avctx->channels; c++) ctx->raw_samples[c] = ctx->raw_samples[c - 1] + channel_size; // allocate crc buffer if (HAVE_BIGENDIAN != sconf->msb_first && sconf->crc_enabled && (avctx->err_recognition & (AV_EF_CRCCHECK|AV_EF_CAREFUL))) { ctx->crc_buffer = av_malloc_array(ctx->cur_frame_length * avctx->channels * av_get_bytes_per_sample(avctx->sample_fmt), sizeof(*ctx->crc_buffer)); if (!ctx->crc_buffer) { av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n"); ret = AVERROR(ENOMEM); goto fail; } } ff_bswapdsp_init(&ctx->bdsp); return 0; fail: return ret; } /** Flush (reset) the frame ID after seeking. */ static av_cold void flush(AVCodecContext *avctx) { ALSDecContext *ctx = avctx->priv_data; ctx->frame_id = 0; } AVCodec ff_als_decoder = { .name = "als", .long_name = NULL_IF_CONFIG_SMALL("MPEG-4 Audio Lossless Coding (ALS)"), .type = AVMEDIA_TYPE_AUDIO, .id = AV_CODEC_ID_MP4ALS, .priv_data_size = sizeof(ALSDecContext), .init = decode_init, .close = decode_end, .decode = decode_frame, .flush = flush, .capabilities = AV_CODEC_CAP_SUBFRAMES | AV_CODEC_CAP_DR1, .caps_internal = FF_CODEC_CAP_INIT_CLEANUP, };