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FFmpeg/libavcodec/alsdec.c

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  1. /*

  2.  * MPEG-4 ALS decoder

  3.  * Copyright (c) 2009 Thilo Borgmann <thilo.borgmann _at_ googlemail.com>

  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.  * MPEG-4 ALS decoder

  25.  * @author Thilo Borgmann <thilo.borgmann _at_ googlemail.com>

  26.  */

  27. 

  28. 

  29. //#define DEBUG

  30. 

  31. 

  32. #include "avcodec.h"

  33. #include "get_bits.h"

  34. #include "unary.h"

  35. #include "mpeg4audio.h"

  36. #include "bytestream.h"

  37. #include "bgmc.h"

  38. #include "dsputil.h"

  39. #include "libavcore/samplefmt.h"

  40. #include "libavutil/crc.h"

  41. 

  42. #include <stdint.h>

  43. 

  44. /** Rice parameters and corresponding index offsets for decoding the

  45.  *  indices of scaled PARCOR values. The table chosen is set globally

  46.  *  by the encoder and stored in ALSSpecificConfig.

  47.  */

  48. static const int8_t parcor_rice_table[3][20][2] = {

  49.     { {-52, 4}, {-29, 5}, {-31, 4}, { 19, 4}, {-16, 4},

  50.       { 12, 3}, { -7, 3}, {  9, 3}, { -5, 3}, {  6, 3},

  51.       { -4, 3}, {  3, 3}, { -3, 2}, {  3, 2}, { -2, 2},

  52.       {  3, 2}, { -1, 2}, {  2, 2}, { -1, 2}, {  2, 2} },

  53.     { {-58, 3}, {-42, 4}, {-46, 4}, { 37, 5}, {-36, 4},

  54.       { 29, 4}, {-29, 4}, { 25, 4}, {-23, 4}, { 20, 4},

  55.       {-17, 4}, { 16, 4}, {-12, 4}, { 12, 3}, {-10, 4},

  56.       {  7, 3}, { -4, 4}, {  3, 3}, { -1, 3}, {  1, 3} },

  57.     { {-59, 3}, {-45, 5}, {-50, 4}, { 38, 4}, {-39, 4},

  58.       { 32, 4}, {-30, 4}, { 25, 3}, {-23, 3}, { 20, 3},

  59.       {-20, 3}, { 16, 3}, {-13, 3}, { 10, 3}, { -7, 3},

  60.       {  3, 3}, {  0, 3}, { -1, 3}, {  2, 3}, { -1, 2} }

  61. };

  62. 

  63. 

  64. /** Scaled PARCOR values used for the first two PARCOR coefficients.

  65.  *  To be indexed by the Rice coded indices.

  66.  *  Generated by: parcor_scaled_values[i] = 32 + ((i * (i+1)) << 7) - (1 << 20)

  67.  *  Actual values are divided by 32 in order to be stored in 16 bits.

  68.  */

  69. static const int16_t parcor_scaled_values[] = {

  70.     -1048544 / 32, -1048288 / 32, -1047776 / 32, -1047008 / 32,

  71.     -1045984 / 32, -1044704 / 32, -1043168 / 32, -1041376 / 32,

  72.     -1039328 / 32, -1037024 / 32, -1034464 / 32, -1031648 / 32,

  73.     -1028576 / 32, -1025248 / 32, -1021664 / 32, -1017824 / 32,

  74.     -1013728 / 32, -1009376 / 32, -1004768 / 32,  -999904 / 32,

  75.      -994784 / 32,  -989408 / 32,  -983776 / 32,  -977888 / 32,

  76.      -971744 / 32,  -965344 / 32,  -958688 / 32,  -951776 / 32,

  77.      -944608 / 32,  -937184 / 32,  -929504 / 32,  -921568 / 32,

  78.      -913376 / 32,  -904928 / 32,  -896224 / 32,  -887264 / 32,

  79.      -878048 / 32,  -868576 / 32,  -858848 / 32,  -848864 / 32,

  80.      -838624 / 32,  -828128 / 32,  -817376 / 32,  -806368 / 32,

  81.      -795104 / 32,  -783584 / 32,  -771808 / 32,  -759776 / 32,

  82.      -747488 / 32,  -734944 / 32,  -722144 / 32,  -709088 / 32,

  83.      -695776 / 32,  -682208 / 32,  -668384 / 32,  -654304 / 32,

  84.      -639968 / 32,  -625376 / 32,  -610528 / 32,  -595424 / 32,

  85.      -580064 / 32,  -564448 / 32,  -548576 / 32,  -532448 / 32,

  86.      -516064 / 32,  -499424 / 32,  -482528 / 32,  -465376 / 32,

  87.      -447968 / 32,  -430304 / 32,  -412384 / 32,  -394208 / 32,

  88.      -375776 / 32,  -357088 / 32,  -338144 / 32,  -318944 / 32,

  89.      -299488 / 32,  -279776 / 32,  -259808 / 32,  -239584 / 32,

  90.      -219104 / 32,  -198368 / 32,  -177376 / 32,  -156128 / 32,

  91.      -134624 / 32,  -112864 / 32,   -90848 / 32,   -68576 / 32,

  92.       -46048 / 32,   -23264 / 32,     -224 / 32,    23072 / 32,

  93.        46624 / 32,    70432 / 32,    94496 / 32,   118816 / 32,

  94.       143392 / 32,   168224 / 32,   193312 / 32,   218656 / 32,

  95.       244256 / 32,   270112 / 32,   296224 / 32,   322592 / 32,

  96.       349216 / 32,   376096 / 32,   403232 / 32,   430624 / 32,

  97.       458272 / 32,   486176 / 32,   514336 / 32,   542752 / 32,

  98.       571424 / 32,   600352 / 32,   629536 / 32,   658976 / 32,

  99.       688672 / 32,   718624 / 32,   748832 / 32,   779296 / 32,

  100.       810016 / 32,   840992 / 32,   872224 / 32,   903712 / 32,

  101.       935456 / 32,   967456 / 32,   999712 / 32,  1032224 / 32

  102. };

  103. 

  104. 

  105. /** Gain values of p(0) for long-term prediction.

  106.  *  To be indexed by the Rice coded indices.

  107.  */

  108. static const uint8_t ltp_gain_values [4][4] = {

  109.     { 0,  8, 16,  24},

  110.     {32, 40, 48,  56},

  111.     {64, 70, 76,  82},

  112.     {88, 92, 96, 100}

  113. };

  114. 

  115. 

  116. /** Inter-channel weighting factors for multi-channel correlation.

  117.  *  To be indexed by the Rice coded indices.

  118.  */

  119. static const int16_t mcc_weightings[] = {

  120.     204,  192,  179,  166,  153,  140,  128,  115,

  121.     102,   89,   76,   64,   51,   38,   25,   12,

  122.       0,  -12,  -25,  -38,  -51,  -64,  -76,  -89,

  123.    -102, -115, -128, -140, -153, -166, -179, -192

  124. };

  125. 

  126. 

  127. /** Tail codes used in arithmetic coding using block Gilbert-Moore codes.

  128.  */

  129. static const uint8_t tail_code[16][6] = {

  130.     { 74, 44, 25, 13,  7, 3},

  131.     { 68, 42, 24, 13,  7, 3},

  132.     { 58, 39, 23, 13,  7, 3},

  133.     {126, 70, 37, 19, 10, 5},

  134.     {132, 70, 37, 20, 10, 5},

  135.     {124, 70, 38, 20, 10, 5},

  136.     {120, 69, 37, 20, 11, 5},

  137.     {116, 67, 37, 20, 11, 5},

  138.     {108, 66, 36, 20, 10, 5},

  139.     {102, 62, 36, 20, 10, 5},

  140.     { 88, 58, 34, 19, 10, 5},

  141.     {162, 89, 49, 25, 13, 7},

  142.     {156, 87, 49, 26, 14, 7},

  143.     {150, 86, 47, 26, 14, 7},

  144.     {142, 84, 47, 26, 14, 7},

  145.     {131, 79, 46, 26, 14, 7}

  146. };

  147. 

  148. 

  149. enum RA_Flag {

  150.     RA_FLAG_NONE,

  151.     RA_FLAG_FRAMES,

  152.     RA_FLAG_HEADER

  153. };

  154. 

  155. 

  156. typedef struct {

  157.     uint32_t samples;         ///< number of samples, 0xFFFFFFFF if unknown

  158.     int resolution;           ///< 000 = 8-bit; 001 = 16-bit; 010 = 24-bit; 011 = 32-bit

  159.     int floating;             ///< 1 = IEEE 32-bit floating-point, 0 = integer

  160.     int msb_first;            ///< 1 = original CRC calculated on big-endian system, 0 = little-endian

  161.     int frame_length;         ///< frame length for each frame (last frame may differ)

  162.     int ra_distance;          ///< distance between RA frames (in frames, 0...255)

  163.     enum RA_Flag ra_flag;     ///< indicates where the size of ra units is stored

  164.     int adapt_order;          ///< adaptive order: 1 = on, 0 = off

  165.     int coef_table;           ///< table index of Rice code parameters

  166.     int long_term_prediction; ///< long term prediction (LTP): 1 = on, 0 = off

  167.     int max_order;            ///< maximum prediction order (0..1023)

  168.     int block_switching;      ///< number of block switching levels

  169.     int bgmc;                 ///< "Block Gilbert-Moore Code": 1 = on, 0 = off (Rice coding only)

  170.     int sb_part;              ///< sub-block partition

  171.     int joint_stereo;         ///< joint stereo: 1 = on, 0 = off

  172.     int mc_coding;            ///< extended inter-channel coding (multi channel coding): 1 = on, 0 = off

  173.     int chan_config;          ///< indicates that a chan_config_info field is present

  174.     int chan_sort;            ///< channel rearrangement: 1 = on, 0 = off

  175.     int rlslms;               ///< use "Recursive Least Square-Least Mean Square" predictor: 1 = on, 0 = off

  176.     int chan_config_info;     ///< mapping of channels to loudspeaker locations. Unused until setting channel configuration is implemented.

  177.     int *chan_pos;            ///< original channel positions

  178.     int crc_enabled;          ///< enable Cyclic Redundancy Checksum

  179. } ALSSpecificConfig;

  180. 

  181. 

  182. typedef struct {

  183.     int stop_flag;

  184.     int master_channel;

  185.     int time_diff_flag;

  186.     int time_diff_sign;

  187.     int time_diff_index;

  188.     int weighting[6];

  189. } ALSChannelData;

  190. 

  191. 

  192. typedef struct {

  193.     AVCodecContext *avctx;

  194.     ALSSpecificConfig sconf;

  195.     GetBitContext gb;

  196.     DSPContext dsp;

  197.     const AVCRC *crc_table;

  198.     uint32_t crc_org;               ///< CRC value of the original input data

  199.     uint32_t crc;                   ///< CRC value calculated from decoded data

  200.     unsigned int cur_frame_length;  ///< length of the current frame to decode

  201.     unsigned int frame_id;          ///< the frame ID / number of the current frame

  202.     unsigned int js_switch;         ///< if true, joint-stereo decoding is enforced

  203.     unsigned int num_blocks;        ///< number of blocks used in the current frame

  204.     unsigned int s_max;             ///< maximum Rice parameter allowed in entropy coding

  205.     uint8_t *bgmc_lut;              ///< pointer at lookup tables used for BGMC

  206.     int *bgmc_lut_status;           ///< pointer at lookup table status flags used for BGMC

  207.     int ltp_lag_length;             ///< number of bits used for ltp lag value

  208.     int *use_ltp;                   ///< contains use_ltp flags for all channels

  209.     int *ltp_lag;                   ///< contains ltp lag values for all channels

  210.     int **ltp_gain;                 ///< gain values for ltp 5-tap filter for a channel

  211.     int *ltp_gain_buffer;           ///< contains all gain values for ltp 5-tap filter

  212.     int32_t **quant_cof;            ///< quantized parcor coefficients for a channel

  213.     int32_t *quant_cof_buffer;      ///< contains all quantized parcor coefficients

  214.     int32_t **lpc_cof;              ///< coefficients of the direct form prediction filter for a channel

  215.     int32_t *lpc_cof_buffer;        ///< contains all coefficients of the direct form prediction filter

  216.     int32_t *lpc_cof_reversed_buffer; ///< temporary buffer to set up a reversed versio of lpc_cof_buffer

  217.     ALSChannelData **chan_data;     ///< channel data for multi-channel correlation

  218.     ALSChannelData *chan_data_buffer; ///< contains channel data for all channels

  219.     int *reverted_channels;         ///< stores a flag for each reverted channel

  220.     int32_t *prev_raw_samples;      ///< contains unshifted raw samples from the previous block

  221.     int32_t **raw_samples;          ///< decoded raw samples for each channel

  222.     int32_t *raw_buffer;            ///< contains all decoded raw samples including carryover samples

  223.     uint8_t *crc_buffer;            ///< buffer of byte order corrected samples used for CRC check

  224. } ALSDecContext;

  225. 

  226. 

  227. typedef struct {

  228.     unsigned int block_length;      ///< number of samples within the block

  229.     unsigned int ra_block;          ///< if true, this is a random access block

  230.     int          const_block;       ///< if true, this is a constant value block

  231.     int32_t      const_val;         ///< the sample value of a constant block

  232.     int          js_blocks;         ///< true if this block contains a difference signal

  233.     unsigned int shift_lsbs;        ///< shift of values for this block

  234.     unsigned int opt_order;         ///< prediction order of this block

  235.     int          store_prev_samples;///< if true, carryover samples have to be stored

  236.     int          *use_ltp;          ///< if true, long-term prediction is used

  237.     int          *ltp_lag;          ///< lag value for long-term prediction

  238.     int          *ltp_gain;         ///< gain values for ltp 5-tap filter

  239.     int32_t      *quant_cof;        ///< quantized parcor coefficients

  240.     int32_t      *lpc_cof;          ///< coefficients of the direct form prediction

  241.     int32_t      *raw_samples;      ///< decoded raw samples / residuals for this block

  242.     int32_t      *prev_raw_samples; ///< contains unshifted raw samples from the previous block

  243.     int32_t      *raw_other;        ///< decoded raw samples of the other channel of a channel pair

  244. } ALSBlockData;

  245. 

  246. 

  247. static av_cold void dprint_specific_config(ALSDecContext *ctx)

  248. {

  249. #ifdef DEBUG

  250.     AVCodecContext *avctx    = ctx->avctx;

  251.     ALSSpecificConfig *sconf = &ctx->sconf;

  252. 

  253.     dprintf(avctx, "resolution = %i\n",           sconf->resolution);

  254.     dprintf(avctx, "floating = %i\n",             sconf->floating);

  255.     dprintf(avctx, "frame_length = %i\n",         sconf->frame_length);

  256.     dprintf(avctx, "ra_distance = %i\n",          sconf->ra_distance);

  257.     dprintf(avctx, "ra_flag = %i\n",              sconf->ra_flag);

  258.     dprintf(avctx, "adapt_order = %i\n",          sconf->adapt_order);

  259.     dprintf(avctx, "coef_table = %i\n",           sconf->coef_table);

  260.     dprintf(avctx, "long_term_prediction = %i\n", sconf->long_term_prediction);

  261.     dprintf(avctx, "max_order = %i\n",            sconf->max_order);

  262.     dprintf(avctx, "block_switching = %i\n",      sconf->block_switching);

  263.     dprintf(avctx, "bgmc = %i\n",                 sconf->bgmc);

  264.     dprintf(avctx, "sb_part = %i\n",              sconf->sb_part);

  265.     dprintf(avctx, "joint_stereo = %i\n",         sconf->joint_stereo);

  266.     dprintf(avctx, "mc_coding = %i\n",            sconf->mc_coding);

  267.     dprintf(avctx, "chan_config = %i\n",          sconf->chan_config);

  268.     dprintf(avctx, "chan_sort = %i\n",            sconf->chan_sort);

  269.     dprintf(avctx, "RLSLMS = %i\n",               sconf->rlslms);

  270.     dprintf(avctx, "chan_config_info = %i\n",     sconf->chan_config_info);

  271. #endif

  272. }

  273. 

  274. 

  275. /** Read an ALSSpecificConfig from a buffer into the output struct.

  276.  */

  277. static av_cold int read_specific_config(ALSDecContext *ctx)

  278. {

  279.     GetBitContext gb;

  280.     uint64_t ht_size;

  281.     int i, config_offset;

  282.     MPEG4AudioConfig m4ac;

  283.     ALSSpecificConfig *sconf = &ctx->sconf;

  284.     AVCodecContext *avctx    = ctx->avctx;

  285.     uint32_t als_id, header_size, trailer_size;

  286. 

  287.     init_get_bits(&gb, avctx->extradata, avctx->extradata_size * 8);

  288. 

  289.     config_offset = ff_mpeg4audio_get_config(&m4ac, avctx->extradata,

  290.                                              avctx->extradata_size);

  291. 

  292.     if (config_offset < 0)

  293.         return -1;

  294. 

  295.     skip_bits_long(&gb, config_offset);

  296. 

  297.     if (get_bits_left(&gb) < (30 << 3))

  298.         return -1;

  299. 

  300.     // read the fixed items

  301.     als_id                      = get_bits_long(&gb, 32);

  302.     avctx->sample_rate          = m4ac.sample_rate;

  303.     skip_bits_long(&gb, 32); // sample rate already known

  304.     sconf->samples              = get_bits_long(&gb, 32);

  305.     avctx->channels             = m4ac.channels;

  306.     skip_bits(&gb, 16);      // number of channels already knwon

  307.     skip_bits(&gb, 3);       // skip file_type

  308.     sconf->resolution           = get_bits(&gb, 3);

  309.     sconf->floating             = get_bits1(&gb);

  310.     sconf->msb_first            = get_bits1(&gb);

  311.     sconf->frame_length         = get_bits(&gb, 16) + 1;

  312.     sconf->ra_distance          = get_bits(&gb, 8);

  313.     sconf->ra_flag              = get_bits(&gb, 2);

  314.     sconf->adapt_order          = get_bits1(&gb);

  315.     sconf->coef_table           = get_bits(&gb, 2);

  316.     sconf->long_term_prediction = get_bits1(&gb);

  317.     sconf->max_order            = get_bits(&gb, 10);

  318.     sconf->block_switching      = get_bits(&gb, 2);

  319.     sconf->bgmc                 = get_bits1(&gb);

  320.     sconf->sb_part              = get_bits1(&gb);

  321.     sconf->joint_stereo         = get_bits1(&gb);

  322.     sconf->mc_coding            = get_bits1(&gb);

  323.     sconf->chan_config          = get_bits1(&gb);

  324.     sconf->chan_sort            = get_bits1(&gb);

  325.     sconf->crc_enabled          = get_bits1(&gb);

  326.     sconf->rlslms               = get_bits1(&gb);

  327.     skip_bits(&gb, 5);       // skip 5 reserved bits

  328.     skip_bits1(&gb);         // skip aux_data_enabled

  329. 

  330. 

  331.     // check for ALSSpecificConfig struct

  332.     if (als_id != MKBETAG('A','L','S','\0'))

  333.         return -1;

  334. 

  335.     ctx->cur_frame_length = sconf->frame_length;

  336. 

  337.     // read channel config

  338.     if (sconf->chan_config)

  339.         sconf->chan_config_info = get_bits(&gb, 16);

  340.     // TODO: use this to set avctx->channel_layout

  341. 

  342. 

  343.     // read channel sorting

  344.     if (sconf->chan_sort && avctx->channels > 1) {

  345.         int chan_pos_bits = av_ceil_log2(avctx->channels);

  346.         int bits_needed  = avctx->channels * chan_pos_bits + 7;

  347.         if (get_bits_left(&gb) < bits_needed)

  348.             return -1;

  349. 

  350.         if (!(sconf->chan_pos = av_malloc(avctx->channels * sizeof(*sconf->chan_pos))))

  351.             return AVERROR(ENOMEM);

  352. 

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

  354.             sconf->chan_pos[i] = get_bits(&gb, chan_pos_bits);

  355. 

  356.         align_get_bits(&gb);

  357.         // TODO: use this to actually do channel sorting

  358.     } else {

  359.         sconf->chan_sort = 0;

  360.     }

  361. 

  362. 

  363.     // read fixed header and trailer sizes,

  364.     // if size = 0xFFFFFFFF then there is no data field!

  365.     if (get_bits_left(&gb) < 64)

  366.         return -1;

  367. 

  368.     header_size  = get_bits_long(&gb, 32);

  369.     trailer_size = get_bits_long(&gb, 32);

  370.     if (header_size  == 0xFFFFFFFF)

  371.         header_size  = 0;

  372.     if (trailer_size == 0xFFFFFFFF)

  373.         trailer_size = 0;

  374. 

  375.     ht_size = ((int64_t)(header_size) + (int64_t)(trailer_size)) << 3;

  376. 

  377. 

  378.     // skip the header and trailer data

  379.     if (get_bits_left(&gb) < ht_size)

  380.         return -1;

  381. 

  382.     if (ht_size > INT32_MAX)

  383.         return -1;

  384. 

  385.     skip_bits_long(&gb, ht_size);

  386. 

  387. 

  388.     // initialize CRC calculation

  389.     if (sconf->crc_enabled) {

  390.         if (get_bits_left(&gb) < 32)

  391.             return -1;

  392. 

  393.         if (avctx->error_recognition >= FF_ER_CAREFUL) {

  394.             ctx->crc_table = av_crc_get_table(AV_CRC_32_IEEE_LE);

  395.             ctx->crc       = 0xFFFFFFFF;

  396.             ctx->crc_org   = ~get_bits_long(&gb, 32);

  397.         } else

  398.             skip_bits_long(&gb, 32);

  399.     }

  400. 

  401. 

  402.     // no need to read the rest of ALSSpecificConfig (ra_unit_size & aux data)

  403. 

  404.     dprint_specific_config(ctx);

  405. 

  406.     return 0;

  407. }

  408. 

  409. 

  410. /** Check the ALSSpecificConfig for unsupported features.

  411.  */

  412. static int check_specific_config(ALSDecContext *ctx)

  413. {

  414.     ALSSpecificConfig *sconf = &ctx->sconf;

  415.     int error = 0;

  416. 

  417.     // report unsupported feature and set error value

  418.     #define MISSING_ERR(cond, str, errval)              \

  419.     {                                                   \

  420.         if (cond) {                                     \

  421.             av_log_missing_feature(ctx->avctx, str, 0); \

  422.             error = errval;                             \

  423.         }                                               \

  424.     }

  425. 

  426.     MISSING_ERR(sconf->floating,             "Floating point decoding",     -1);

  427.     MISSING_ERR(sconf->rlslms,               "Adaptive RLS-LMS prediction", -1);

  428.     MISSING_ERR(sconf->chan_sort,            "Channel sorting",              0);

  429. 

  430.     return error;

  431. }

  432. 

  433. 

  434. /** Parse the bs_info field to extract the block partitioning used in

  435.  *  block switching mode, refer to ISO/IEC 14496-3, section 11.6.2.

  436.  */

  437. static void parse_bs_info(const uint32_t bs_info, unsigned int n,

  438.                           unsigned int div, unsigned int **div_blocks,

  439.                           unsigned int *num_blocks)

  440. {

  441.     if (n < 31 && ((bs_info << n) & 0x40000000)) {

  442.         // if the level is valid and the investigated bit n is set

  443.         // then recursively check both children at bits (2n+1) and (2n+2)

  444.         n   *= 2;

  445.         div += 1;

  446.         parse_bs_info(bs_info, n + 1, div, div_blocks, num_blocks);

  447.         parse_bs_info(bs_info, n + 2, div, div_blocks, num_blocks);

  448.     } else {

  449.         // else the bit is not set or the last level has been reached

  450.         // (bit implicitly not set)

  451.         **div_blocks = div;

  452.         (*div_blocks)++;

  453.         (*num_blocks)++;

  454.     }

  455. }

  456. 

  457. 

  458. /** Read and decode a Rice codeword.

  459.  */

  460. static int32_t decode_rice(GetBitContext *gb, unsigned int k)

  461. {

  462.     int max = get_bits_left(gb) - k;

  463.     int q   = get_unary(gb, 0, max);

  464.     int r   = k ? get_bits1(gb) : !(q & 1);

  465. 

  466.     if (k > 1) {

  467.         q <<= (k - 1);

  468.         q  += get_bits_long(gb, k - 1);

  469.     } else if (!k) {

  470.         q >>= 1;

  471.     }

  472.     return r ? q : ~q;

  473. }

  474. 

  475. 

  476. /** Convert PARCOR coefficient k to direct filter coefficient.

  477.  */

  478. static void parcor_to_lpc(unsigned int k, const int32_t *par, int32_t *cof)

  479. {

  480.     int i, j;

  481. 

  482.     for (i = 0, j = k - 1; i < j; i++, j--) {

  483.         int tmp1 = ((MUL64(par[k], cof[j]) + (1 << 19)) >> 20);

  484.         cof[j]  += ((MUL64(par[k], cof[i]) + (1 << 19)) >> 20);

  485.         cof[i]  += tmp1;

  486.     }

  487.     if (i == j)

  488.         cof[i] += ((MUL64(par[k], cof[j]) + (1 << 19)) >> 20);

  489. 

  490.     cof[k] = par[k];

  491. }

  492. 

  493. 

  494. /** Read block switching field if necessary and set actual block sizes.

  495.  *  Also assure that the block sizes of the last frame correspond to the

  496.  *  actual number of samples.

  497.  */

  498. static void get_block_sizes(ALSDecContext *ctx, unsigned int *div_blocks,

  499.                             uint32_t *bs_info)

  500. {

  501.     ALSSpecificConfig *sconf     = &ctx->sconf;

  502.     GetBitContext *gb            = &ctx->gb;

  503.     unsigned int *ptr_div_blocks = div_blocks;

  504.     unsigned int b;

  505. 

  506.     if (sconf->block_switching) {

  507.         unsigned int bs_info_len = 1 << (sconf->block_switching + 2);

  508.         *bs_info = get_bits_long(gb, bs_info_len);

  509.         *bs_info <<= (32 - bs_info_len);

  510.     }

  511. 

  512.     ctx->num_blocks = 0;

  513.     parse_bs_info(*bs_info, 0, 0, &ptr_div_blocks, &ctx->num_blocks);

  514. 

  515.     // The last frame may have an overdetermined block structure given in

  516.     // the bitstream. In that case the defined block structure would need

  517.     // more samples than available to be consistent.

  518.     // The block structure is actually used but the block sizes are adapted

  519.     // to fit the actual number of available samples.

  520.     // Example: 5 samples, 2nd level block sizes: 2 2 2 2.

  521.     // This results in the actual block sizes:    2 2 1 0.

  522.     // This is not specified in 14496-3 but actually done by the reference

  523.     // codec RM22 revision 2.

  524.     // This appears to happen in case of an odd number of samples in the last

  525.     // frame which is actually not allowed by the block length switching part

  526.     // of 14496-3.

  527.     // The ALS conformance files feature an odd number of samples in the last

  528.     // frame.

  529. 

  530.     for (b = 0; b < ctx->num_blocks; b++)

  531.         div_blocks[b] = ctx->sconf.frame_length >> div_blocks[b];

  532. 

  533.     if (ctx->cur_frame_length != ctx->sconf.frame_length) {

  534.         unsigned int remaining = ctx->cur_frame_length;

  535. 

  536.         for (b = 0; b < ctx->num_blocks; b++) {

  537.             if (remaining <= div_blocks[b]) {

  538.                 div_blocks[b] = remaining;

  539.                 ctx->num_blocks = b + 1;

  540.                 break;

  541.             }

  542. 

  543.             remaining -= div_blocks[b];

  544.         }

  545.     }

  546. }

  547. 

  548. 

  549. /** Read the block data for a constant block

  550.  */

  551. static void read_const_block_data(ALSDecContext *ctx, ALSBlockData *bd)

  552. {

  553.     ALSSpecificConfig *sconf = &ctx->sconf;

  554.     AVCodecContext *avctx    = ctx->avctx;

  555.     GetBitContext *gb        = &ctx->gb;

  556. 

  557.     bd->const_val    = 0;

  558.     bd->const_block  = get_bits1(gb);    // 1 = constant value, 0 = zero block (silence)

  559.     bd->js_blocks    = get_bits1(gb);

  560. 

  561.     // skip 5 reserved bits

  562.     skip_bits(gb, 5);

  563. 

  564.     if (bd->const_block) {

  565.         unsigned int const_val_bits = sconf->floating ? 24 : avctx->bits_per_raw_sample;

  566.         bd->const_val = get_sbits_long(gb, const_val_bits);

  567.     }

  568. 

  569.     // ensure constant block decoding by reusing this field

  570.     bd->const_block = 1;

  571. }

  572. 

  573. 

  574. /** Decode the block data for a constant block

  575.  */

  576. static void decode_const_block_data(ALSDecContext *ctx, ALSBlockData *bd)

  577. {

  578.     int      smp = bd->block_length;

  579.     int32_t  val = bd->const_val;

  580.     int32_t *dst = bd->raw_samples;

  581. 

  582.     // write raw samples into buffer

  583.     for (; smp; smp--)

  584.         *dst++ = val;

  585. }

  586. 

  587. 

  588. /** Read the block data for a non-constant block

  589.  */

  590. static int read_var_block_data(ALSDecContext *ctx, ALSBlockData *bd)

  591. {

  592.     ALSSpecificConfig *sconf = &ctx->sconf;

  593.     AVCodecContext *avctx    = ctx->avctx;

  594.     GetBitContext *gb        = &ctx->gb;

  595.     unsigned int k;

  596.     unsigned int s[8];

  597.     unsigned int sx[8];

  598.     unsigned int sub_blocks, log2_sub_blocks, sb_length;

  599.     unsigned int start      = 0;

  600.     unsigned int opt_order;

  601.     int          sb;

  602.     int32_t      *quant_cof = bd->quant_cof;

  603.     int32_t      *current_res;

  604. 

  605. 

  606.     // ensure variable block decoding by reusing this field

  607.     bd->const_block = 0;

  608. 

  609.     bd->opt_order   = 1;

  610.     bd->js_blocks   = get_bits1(gb);

  611. 

  612.     opt_order       = bd->opt_order;

  613. 

  614.     // determine the number of subblocks for entropy decoding

  615.     if (!sconf->bgmc && !sconf->sb_part) {

  616.         log2_sub_blocks = 0;

  617.     } else {

  618.         if (sconf->bgmc && sconf->sb_part)

  619.             log2_sub_blocks = get_bits(gb, 2);

  620.         else

  621.             log2_sub_blocks = 2 * get_bits1(gb);

  622.     }

  623. 

  624.     sub_blocks = 1 << log2_sub_blocks;

  625. 

  626.     // do not continue in case of a damaged stream since

  627.     // block_length must be evenly divisible by sub_blocks

  628.     if (bd->block_length & (sub_blocks - 1)) {

  629.         av_log(avctx, AV_LOG_WARNING,

  630.                "Block length is not evenly divisible by the number of subblocks.\n");

  631.         return -1;

  632.     }

  633. 

  634.     sb_length = bd->block_length >> log2_sub_blocks;

  635. 

  636.     if (sconf->bgmc) {

  637.         s[0] = get_bits(gb, 8 + (sconf->resolution > 1));

  638.         for (k = 1; k < sub_blocks; k++)

  639.             s[k] = s[k - 1] + decode_rice(gb, 2);

  640. 

  641.         for (k = 0; k < sub_blocks; k++) {

  642.             sx[k]   = s[k] & 0x0F;

  643.             s [k] >>= 4;

  644.         }

  645.     } else {

  646.         s[0] = get_bits(gb, 4 + (sconf->resolution > 1));

  647.         for (k = 1; k < sub_blocks; k++)

  648.             s[k] = s[k - 1] + decode_rice(gb, 0);

  649.     }

  650. 

  651.     if (get_bits1(gb))

  652.         bd->shift_lsbs = get_bits(gb, 4) + 1;

  653. 

  654.     bd->store_prev_samples = (bd->js_blocks && bd->raw_other) || bd->shift_lsbs;

  655. 

  656. 

  657.     if (!sconf->rlslms) {

  658.         if (sconf->adapt_order) {

  659.             int opt_order_length = av_ceil_log2(av_clip((bd->block_length >> 3) - 1,

  660.                                                 2, sconf->max_order + 1));

  661.             bd->opt_order        = get_bits(gb, opt_order_length);

  662.         } else {

  663.             bd->opt_order = sconf->max_order;

  664.         }

  665. 

  666.         opt_order = bd->opt_order;

  667. 

  668.         if (opt_order) {

  669.             int add_base;

  670. 

  671.             if (sconf->coef_table == 3) {

  672.                 add_base = 0x7F;

  673. 

  674.                 // read coefficient 0

  675.                 quant_cof[0] = 32 * parcor_scaled_values[get_bits(gb, 7)];

  676. 

  677.                 // read coefficient 1

  678.                 if (opt_order > 1)

  679.                     quant_cof[1] = -32 * parcor_scaled_values[get_bits(gb, 7)];

  680. 

  681.                 // read coefficients 2 to opt_order

  682.                 for (k = 2; k < opt_order; k++)

  683.                     quant_cof[k] = get_bits(gb, 7);

  684.             } else {

  685.                 int k_max;

  686.                 add_base = 1;

  687. 

  688.                 // read coefficient 0 to 19

  689.                 k_max = FFMIN(opt_order, 20);

  690.                 for (k = 0; k < k_max; k++) {

  691.                     int rice_param = parcor_rice_table[sconf->coef_table][k][1];

  692.                     int offset     = parcor_rice_table[sconf->coef_table][k][0];

  693.                     quant_cof[k] = decode_rice(gb, rice_param) + offset;

  694.                 }

  695. 

  696.                 // read coefficients 20 to 126

  697.                 k_max = FFMIN(opt_order, 127);

  698.                 for (; k < k_max; k++)

  699.                     quant_cof[k] = decode_rice(gb, 2) + (k & 1);

  700. 

  701.                 // read coefficients 127 to opt_order

  702.                 for (; k < opt_order; k++)

  703.                     quant_cof[k] = decode_rice(gb, 1);

  704. 

  705.                 quant_cof[0] = 32 * parcor_scaled_values[quant_cof[0] + 64];

  706. 

  707.                 if (opt_order > 1)

  708.                     quant_cof[1] = -32 * parcor_scaled_values[quant_cof[1] + 64];

  709.             }

  710. 

  711.             for (k = 2; k < opt_order; k++)

  712.                 quant_cof[k] = (quant_cof[k] << 14) + (add_base << 13);

  713.         }

  714.     }

  715. 

  716.     // read LTP gain and lag values

  717.     if (sconf->long_term_prediction) {

  718.         *bd->use_ltp = get_bits1(gb);

  719. 

  720.         if (*bd->use_ltp) {

  721.             int r, c;

  722. 

  723.             bd->ltp_gain[0]   = decode_rice(gb, 1) << 3;

  724.             bd->ltp_gain[1]   = decode_rice(gb, 2) << 3;

  725. 

  726.             r                 = get_unary(gb, 0, 4);

  727.             c                 = get_bits(gb, 2);

  728.             bd->ltp_gain[2]   = ltp_gain_values[r][c];

  729. 

  730.             bd->ltp_gain[3]   = decode_rice(gb, 2) << 3;

  731.             bd->ltp_gain[4]   = decode_rice(gb, 1) << 3;

  732. 

  733.             *bd->ltp_lag      = get_bits(gb, ctx->ltp_lag_length);

  734.             *bd->ltp_lag     += FFMAX(4, opt_order + 1);

  735.         }

  736.     }

  737. 

  738.     // read first value and residuals in case of a random access block

  739.     if (bd->ra_block) {

  740.         if (opt_order)

  741.             bd->raw_samples[0] = decode_rice(gb, avctx->bits_per_raw_sample - 4);

  742.         if (opt_order > 1)

  743.             bd->raw_samples[1] = decode_rice(gb, FFMIN(s[0] + 3, ctx->s_max));

  744.         if (opt_order > 2)

  745.             bd->raw_samples[2] = decode_rice(gb, FFMIN(s[0] + 1, ctx->s_max));

  746. 

  747.         start = FFMIN(opt_order, 3);

  748.     }

  749. 

  750.     // read all residuals

  751.     if (sconf->bgmc) {

  752.         int          delta[8];

  753.         unsigned int k    [8];

  754.         unsigned int b = av_clip((av_ceil_log2(bd->block_length) - 3) >> 1, 0, 5);

  755.         unsigned int i = start;

  756. 

  757.         // read most significant bits

  758.         unsigned int high;

  759.         unsigned int low;

  760.         unsigned int value;

  761. 

  762.         ff_bgmc_decode_init(gb, &high, &low, &value);

  763. 

  764.         current_res = bd->raw_samples + start;

  765. 

  766.         for (sb = 0; sb < sub_blocks; sb++, i = 0) {

  767.             k    [sb] = s[sb] > b ? s[sb] - b : 0;

  768.             delta[sb] = 5 - s[sb] + k[sb];

  769. 

  770.             ff_bgmc_decode(gb, sb_length, current_res,

  771.                         delta[sb], sx[sb], &high, &low, &value, ctx->bgmc_lut, ctx->bgmc_lut_status);

  772. 

  773.             current_res += sb_length;

  774.         }

  775. 

  776.         ff_bgmc_decode_end(gb);

  777. 

  778. 

  779.         // read least significant bits and tails

  780.         i = start;

  781.         current_res = bd->raw_samples + start;

  782. 

  783.         for (sb = 0; sb < sub_blocks; sb++, i = 0) {

  784.             unsigned int cur_tail_code = tail_code[sx[sb]][delta[sb]];

  785.             unsigned int cur_k         = k[sb];

  786.             unsigned int cur_s         = s[sb];

  787. 

  788.             for (; i < sb_length; i++) {

  789.                 int32_t res = *current_res;

  790. 

  791.                 if (res == cur_tail_code) {

  792.                     unsigned int max_msb =   (2 + (sx[sb] > 2) + (sx[sb] > 10))

  793.                                           << (5 - delta[sb]);

  794. 

  795.                     res = decode_rice(gb, cur_s);

  796. 

  797.                     if (res >= 0) {

  798.                         res += (max_msb    ) << cur_k;

  799.                     } else {

  800.                         res -= (max_msb - 1) << cur_k;

  801.                     }

  802.                 } else {

  803.                     if (res > cur_tail_code)

  804.                         res--;

  805. 

  806.                     if (res & 1)

  807.                         res = -res;

  808. 

  809.                     res >>= 1;

  810. 

  811.                     if (cur_k) {

  812.                         res <<= cur_k;

  813.                         res  |= get_bits_long(gb, cur_k);

  814.                     }

  815.                 }

  816. 

  817.                 *current_res++ = res;

  818.             }

  819.         }

  820.     } else {

  821.         current_res = bd->raw_samples + start;

  822. 

  823.         for (sb = 0; sb < sub_blocks; sb++, start = 0)

  824.             for (; start < sb_length; start++)

  825.                 *current_res++ = decode_rice(gb, s[sb]);

  826.      }

  827. 

  828.     if (!sconf->mc_coding || ctx->js_switch)

  829.         align_get_bits(gb);

  830. 

  831.     return 0;

  832. }

  833. 

  834. 

  835. /** Decode the block data for a non-constant block

  836.  */

  837. static int decode_var_block_data(ALSDecContext *ctx, ALSBlockData *bd)

  838. {

  839.     ALSSpecificConfig *sconf = &ctx->sconf;

  840.     unsigned int block_length = bd->block_length;

  841.     unsigned int smp = 0;

  842.     unsigned int k;

  843.     int opt_order             = bd->opt_order;

  844.     int sb;

  845.     int64_t y;

  846.     int32_t *quant_cof        = bd->quant_cof;

  847.     int32_t *lpc_cof          = bd->lpc_cof;

  848.     int32_t *raw_samples      = bd->raw_samples;

  849.     int32_t *raw_samples_end  = bd->raw_samples + bd->block_length;

  850.     int32_t *lpc_cof_reversed = ctx->lpc_cof_reversed_buffer;

  851. 

  852.     // reverse long-term prediction

  853.     if (*bd->use_ltp) {

  854.         int ltp_smp;

  855. 

  856.         for (ltp_smp = FFMAX(*bd->ltp_lag - 2, 0); ltp_smp < block_length; ltp_smp++) {

  857.             int center = ltp_smp - *bd->ltp_lag;

  858.             int begin  = FFMAX(0, center - 2);

  859.             int end    = center + 3;

  860.             int tab    = 5 - (end - begin);

  861.             int base;

  862. 

  863.             y = 1 << 6;

  864. 

  865.             for (base = begin; base < end; base++, tab++)

  866.                 y += MUL64(bd->ltp_gain[tab], raw_samples[base]);

  867. 

  868.             raw_samples[ltp_smp] += y >> 7;

  869.         }

  870.     }

  871. 

  872.     // reconstruct all samples from residuals

  873.     if (bd->ra_block) {

  874.         for (smp = 0; smp < opt_order; smp++) {

  875.             y = 1 << 19;

  876. 

  877.             for (sb = 0; sb < smp; sb++)

  878.                 y += MUL64(lpc_cof[sb], raw_samples[-(sb + 1)]);

  879. 

  880.             *raw_samples++ -= y >> 20;

  881.             parcor_to_lpc(smp, quant_cof, lpc_cof);

  882.         }

  883.     } else {

  884.         for (k = 0; k < opt_order; k++)

  885.             parcor_to_lpc(k, quant_cof, lpc_cof);

  886. 

  887.         // store previous samples in case that they have to be altered

  888.         if (bd->store_prev_samples)

  889.             memcpy(bd->prev_raw_samples, raw_samples - sconf->max_order,

  890.                    sizeof(*bd->prev_raw_samples) * sconf->max_order);

  891. 

  892.         // reconstruct difference signal for prediction (joint-stereo)

  893.         if (bd->js_blocks && bd->raw_other) {

  894.             int32_t *left, *right;

  895. 

  896.             if (bd->raw_other > raw_samples) {  // D = R - L

  897.                 left  = raw_samples;

  898.                 right = bd->raw_other;

  899.             } else {                                // D = R - L

  900.                 left  = bd->raw_other;

  901.                 right = raw_samples;

  902.             }

  903. 

  904.             for (sb = -1; sb >= -sconf->max_order; sb--)

  905.                 raw_samples[sb] = right[sb] - left[sb];

  906.         }

  907. 

  908.         // reconstruct shifted signal

  909.         if (bd->shift_lsbs)

  910.             for (sb = -1; sb >= -sconf->max_order; sb--)

  911.                 raw_samples[sb] >>= bd->shift_lsbs;

  912.     }

  913. 

  914.     // reverse linear prediction coefficients for efficiency

  915.     lpc_cof = lpc_cof + opt_order;

  916. 

  917.     for (sb = 0; sb < opt_order; sb++)

  918.         lpc_cof_reversed[sb] = lpc_cof[-(sb + 1)];

  919. 

  920.     // reconstruct raw samples

  921.     raw_samples = bd->raw_samples + smp;

  922.     lpc_cof     = lpc_cof_reversed + opt_order;

  923. 

  924.     for (; raw_samples < raw_samples_end; raw_samples++) {

  925.         y = 1 << 19;

  926. 

  927.         for (sb = -opt_order; sb < 0; sb++)

  928.             y += MUL64(lpc_cof[sb], raw_samples[sb]);

  929. 

  930.         *raw_samples -= y >> 20;

  931.     }

  932. 

  933.     raw_samples = bd->raw_samples;

  934. 

  935.     // restore previous samples in case that they have been altered

  936.     if (bd->store_prev_samples)

  937.         memcpy(raw_samples - sconf->max_order, bd->prev_raw_samples,

  938.                sizeof(*raw_samples) * sconf->max_order);

  939. 

  940.     return 0;

  941. }

  942. 

  943. 

  944. /** Read the block data.

  945.  */

  946. static int read_block(ALSDecContext *ctx, ALSBlockData *bd)

  947. {

  948.     GetBitContext *gb        = &ctx->gb;

  949. 

  950.     // read block type flag and read the samples accordingly

  951.     if (get_bits1(gb)) {

  952.         if (read_var_block_data(ctx, bd))

  953.             return -1;

  954.     } else {

  955.         read_const_block_data(ctx, bd);

  956.     }

  957. 

  958.     return 0;

  959. }

  960. 

  961. 

  962. /** Decode the block data.

  963.  */

  964. static int decode_block(ALSDecContext *ctx, ALSBlockData *bd)

  965. {

  966.     unsigned int smp;

  967. 

  968.     // read block type flag and read the samples accordingly

  969.     if (bd->const_block)

  970.         decode_const_block_data(ctx, bd);

  971.     else if (decode_var_block_data(ctx, bd))

  972.         return -1;

  973. 

  974.     // TODO: read RLSLMS extension data

  975. 

  976.     if (bd->shift_lsbs)

  977.         for (smp = 0; smp < bd->block_length; smp++)

  978.             bd->raw_samples[smp] <<= bd->shift_lsbs;

  979. 

  980.     return 0;

  981. }

  982. 

  983. 

  984. /** Read and decode block data successively.

  985.  */

  986. static int read_decode_block(ALSDecContext *ctx, ALSBlockData *bd)

  987. {

  988.     int ret;

  989. 

  990.     ret = read_block(ctx, bd);

  991. 

  992.     if (ret)

  993.         return ret;

  994. 

  995.     ret = decode_block(ctx, bd);

  996. 

  997.     return ret;

  998. }

  999. 

  1000. 

  1001. /** Compute the number of samples left to decode for the current frame and

  1002.  *  sets these samples to zero.

  1003.  */

  1004. static void zero_remaining(unsigned int b, unsigned int b_max,

  1005.                            const unsigned int *div_blocks, int32_t *buf)

  1006. {

  1007.     unsigned int count = 0;

  1008. 

  1009.     while (b < b_max)

  1010.         count += div_blocks[b];

  1011. 

  1012.     if (count)

  1013.         memset(buf, 0, sizeof(*buf) * count);

  1014. }

  1015. 

  1016. 

  1017. /** Decode blocks independently.

  1018.  */

  1019. static int decode_blocks_ind(ALSDecContext *ctx, unsigned int ra_frame,

  1020.                              unsigned int c, const unsigned int *div_blocks,

  1021.                              unsigned int *js_blocks)

  1022. {

  1023.     unsigned int b;

  1024.     ALSBlockData bd;

  1025. 

  1026.     memset(&bd, 0, sizeof(ALSBlockData));

  1027. 

  1028.     bd.ra_block         = ra_frame;

  1029.     bd.use_ltp          = ctx->use_ltp;

  1030.     bd.ltp_lag          = ctx->ltp_lag;

  1031.     bd.ltp_gain         = ctx->ltp_gain[0];

  1032.     bd.quant_cof        = ctx->quant_cof[0];

  1033.     bd.lpc_cof          = ctx->lpc_cof[0];

  1034.     bd.prev_raw_samples = ctx->prev_raw_samples;

  1035.     bd.raw_samples      = ctx->raw_samples[c];

  1036. 

  1037. 

  1038.     for (b = 0; b < ctx->num_blocks; b++) {

  1039.         bd.shift_lsbs       = 0;

  1040.         bd.block_length     = div_blocks[b];

  1041. 

  1042.         if (read_decode_block(ctx, &bd)) {

  1043.             // damaged block, write zero for the rest of the frame

  1044.             zero_remaining(b, ctx->num_blocks, div_blocks, bd.raw_samples);

  1045.             return -1;

  1046.         }

  1047.         bd.raw_samples += div_blocks[b];

  1048.         bd.ra_block     = 0;

  1049.     }

  1050. 

  1051.     return 0;

  1052. }

  1053. 

  1054. 

  1055. /** Decode blocks dependently.

  1056.  */

  1057. static int decode_blocks(ALSDecContext *ctx, unsigned int ra_frame,

  1058.                          unsigned int c, const unsigned int *div_blocks,

  1059.                          unsigned int *js_blocks)

  1060. {

  1061.     ALSSpecificConfig *sconf = &ctx->sconf;

  1062.     unsigned int offset = 0;

  1063.     unsigned int b;

  1064.     ALSBlockData bd[2];

  1065. 

  1066.     memset(bd, 0, 2 * sizeof(ALSBlockData));

  1067. 

  1068.     bd[0].ra_block         = ra_frame;

  1069.     bd[0].use_ltp          = ctx->use_ltp;

  1070.     bd[0].ltp_lag          = ctx->ltp_lag;

  1071.     bd[0].ltp_gain         = ctx->ltp_gain[0];

  1072.     bd[0].quant_cof        = ctx->quant_cof[0];

  1073.     bd[0].lpc_cof          = ctx->lpc_cof[0];

  1074.     bd[0].prev_raw_samples = ctx->prev_raw_samples;

  1075.     bd[0].js_blocks        = *js_blocks;

  1076. 

  1077.     bd[1].ra_block         = ra_frame;

  1078.     bd[1].use_ltp          = ctx->use_ltp;

  1079.     bd[1].ltp_lag          = ctx->ltp_lag;

  1080.     bd[1].ltp_gain         = ctx->ltp_gain[0];

  1081.     bd[1].quant_cof        = ctx->quant_cof[0];

  1082.     bd[1].lpc_cof          = ctx->lpc_cof[0];

  1083.     bd[1].prev_raw_samples = ctx->prev_raw_samples;

  1084.     bd[1].js_blocks        = *(js_blocks + 1);

  1085. 

  1086.     // decode all blocks

  1087.     for (b = 0; b < ctx->num_blocks; b++) {

  1088.         unsigned int s;

  1089. 

  1090.         bd[0].shift_lsbs   = 0;

  1091.         bd[1].shift_lsbs   = 0;

  1092. 

  1093.         bd[0].block_length = div_blocks[b];

  1094.         bd[1].block_length = div_blocks[b];

  1095. 

  1096.         bd[0].raw_samples  = ctx->raw_samples[c    ] + offset;

  1097.         bd[1].raw_samples  = ctx->raw_samples[c + 1] + offset;

  1098. 

  1099.         bd[0].raw_other    = bd[1].raw_samples;

  1100.         bd[1].raw_other    = bd[0].raw_samples;

  1101. 

  1102.         if(read_decode_block(ctx, &bd[0]) || read_decode_block(ctx, &bd[1])) {

  1103.             // damaged block, write zero for the rest of the frame

  1104.             zero_remaining(b, ctx->num_blocks, div_blocks, bd[0].raw_samples);

  1105.             zero_remaining(b, ctx->num_blocks, div_blocks, bd[1].raw_samples);

  1106.             return -1;

  1107.         }

  1108. 

  1109.         // reconstruct joint-stereo blocks

  1110.         if (bd[0].js_blocks) {

  1111.             if (bd[1].js_blocks)

  1112.                 av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel pair!\n");

  1113. 

  1114.             for (s = 0; s < div_blocks[b]; s++)

  1115.                 bd[0].raw_samples[s] = bd[1].raw_samples[s] - bd[0].raw_samples[s];

  1116.         } else if (bd[1].js_blocks) {

  1117.             for (s = 0; s < div_blocks[b]; s++)

  1118.                 bd[1].raw_samples[s] = bd[1].raw_samples[s] + bd[0].raw_samples[s];

  1119.         }

  1120. 

  1121.         offset  += div_blocks[b];

  1122.         bd[0].ra_block = 0;

  1123.         bd[1].ra_block = 0;

  1124.     }

  1125. 

  1126.     // store carryover raw samples,

  1127.     // the others channel raw samples are stored by the calling function.

  1128.     memmove(ctx->raw_samples[c] - sconf->max_order,

  1129.             ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1130.             sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1131. 

  1132.     return 0;

  1133. }

  1134. 

  1135. 

  1136. /** Read the channel data.

  1137.   */

  1138. static int read_channel_data(ALSDecContext *ctx, ALSChannelData *cd, int c)

  1139. {

  1140.     GetBitContext *gb       = &ctx->gb;

  1141.     ALSChannelData *current = cd;

  1142.     unsigned int channels   = ctx->avctx->channels;

  1143.     int entries             = 0;

  1144. 

  1145.     while (entries < channels && !(current->stop_flag = get_bits1(gb))) {

  1146.         current->master_channel = get_bits_long(gb, av_ceil_log2(channels));

  1147. 

  1148.         if (current->master_channel >= channels) {

  1149.             av_log(ctx->avctx, AV_LOG_ERROR, "Invalid master channel!\n");

  1150.             return -1;

  1151.         }

  1152. 

  1153.         if (current->master_channel != c) {

  1154.             current->time_diff_flag = get_bits1(gb);

  1155.             current->weighting[0]   = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 32)];

  1156.             current->weighting[1]   = mcc_weightings[av_clip(decode_rice(gb, 2) + 14, 0, 32)];

  1157.             current->weighting[2]   = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 32)];

  1158. 

  1159.             if (current->time_diff_flag) {

  1160.                 current->weighting[3] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 32)];

  1161.                 current->weighting[4] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 32)];

  1162.                 current->weighting[5] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 32)];

  1163. 

  1164.                 current->time_diff_sign  = get_bits1(gb);

  1165.                 current->time_diff_index = get_bits(gb, ctx->ltp_lag_length - 3) + 3;

  1166.             }

  1167.         }

  1168. 

  1169.         current++;

  1170.         entries++;

  1171.     }

  1172. 

  1173.     if (entries == channels) {

  1174.         av_log(ctx->avctx, AV_LOG_ERROR, "Damaged channel data!\n");

  1175.         return -1;

  1176.     }

  1177. 

  1178.     align_get_bits(gb);

  1179.     return 0;

  1180. }

  1181. 

  1182. 

  1183. /** Recursively reverts the inter-channel correlation for a block.

  1184.  */

  1185. static int revert_channel_correlation(ALSDecContext *ctx, ALSBlockData *bd,

  1186.                                        ALSChannelData **cd, int *reverted,

  1187.                                        unsigned int offset, int c)

  1188. {

  1189.     ALSChannelData *ch = cd[c];

  1190.     unsigned int   dep = 0;

  1191.     unsigned int channels = ctx->avctx->channels;

  1192. 

  1193.     if (reverted[c])

  1194.         return 0;

  1195. 

  1196.     reverted[c] = 1;

  1197. 

  1198.     while (dep < channels && !ch[dep].stop_flag) {

  1199.         revert_channel_correlation(ctx, bd, cd, reverted, offset,

  1200.                                    ch[dep].master_channel);

  1201. 

  1202.         dep++;

  1203.     }

  1204. 

  1205.     if (dep == channels) {

  1206.         av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel correlation!\n");

  1207.         return -1;

  1208.     }

  1209. 

  1210.     bd->use_ltp     = ctx->use_ltp + c;

  1211.     bd->ltp_lag     = ctx->ltp_lag + c;

  1212.     bd->ltp_gain    = ctx->ltp_gain[c];

  1213.     bd->lpc_cof     = ctx->lpc_cof[c];

  1214.     bd->quant_cof   = ctx->quant_cof[c];

  1215.     bd->raw_samples = ctx->raw_samples[c] + offset;

  1216. 

  1217.     dep = 0;

  1218.     while (!ch[dep].stop_flag) {

  1219.         unsigned int smp;

  1220.         unsigned int begin = 1;

  1221.         unsigned int end   = bd->block_length - 1;

  1222.         int64_t y;

  1223.         int32_t *master = ctx->raw_samples[ch[dep].master_channel] + offset;

  1224. 

  1225.         if (ch[dep].time_diff_flag) {

  1226.             int t = ch[dep].time_diff_index;

  1227. 

  1228.             if (ch[dep].time_diff_sign) {

  1229.                 t      = -t;

  1230.                 begin -= t;

  1231.             } else {

  1232.                 end   -= t;

  1233.             }

  1234. 

  1235.             for (smp = begin; smp < end; smp++) {

  1236.                 y  = (1 << 6) +

  1237.                      MUL64(ch[dep].weighting[0], master[smp - 1    ]) +

  1238.                      MUL64(ch[dep].weighting[1], master[smp        ]) +

  1239.                      MUL64(ch[dep].weighting[2], master[smp + 1    ]) +

  1240.                      MUL64(ch[dep].weighting[3], master[smp - 1 + t]) +

  1241.                      MUL64(ch[dep].weighting[4], master[smp     + t]) +

  1242.                      MUL64(ch[dep].weighting[5], master[smp + 1 + t]);

  1243. 

  1244.                 bd->raw_samples[smp] += y >> 7;

  1245.             }

  1246.         } else {

  1247.             for (smp = begin; smp < end; smp++) {

  1248.                 y  = (1 << 6) +

  1249.                      MUL64(ch[dep].weighting[0], master[smp - 1]) +

  1250.                      MUL64(ch[dep].weighting[1], master[smp    ]) +

  1251.                      MUL64(ch[dep].weighting[2], master[smp + 1]);

  1252. 

  1253.                 bd->raw_samples[smp] += y >> 7;

  1254.             }

  1255.         }

  1256. 

  1257.         dep++;

  1258.     }

  1259. 

  1260.     return 0;

  1261. }

  1262. 

  1263. 

  1264. /** Read the frame data.

  1265.  */

  1266. static int read_frame_data(ALSDecContext *ctx, unsigned int ra_frame)

  1267. {

  1268.     ALSSpecificConfig *sconf = &ctx->sconf;

  1269.     AVCodecContext *avctx    = ctx->avctx;

  1270.     GetBitContext *gb = &ctx->gb;

  1271.     unsigned int div_blocks[32];                ///< block sizes.

  1272.     unsigned int c;

  1273.     unsigned int js_blocks[2];

  1274. 

  1275.     uint32_t bs_info = 0;

  1276. 

  1277.     // skip the size of the ra unit if present in the frame

  1278.     if (sconf->ra_flag == RA_FLAG_FRAMES && ra_frame)

  1279.         skip_bits_long(gb, 32);

  1280. 

  1281.     if (sconf->mc_coding && sconf->joint_stereo) {

  1282.         ctx->js_switch = get_bits1(gb);

  1283.         align_get_bits(gb);

  1284.     }

  1285. 

  1286.     if (!sconf->mc_coding || ctx->js_switch) {

  1287.         int independent_bs = !sconf->joint_stereo;

  1288. 

  1289.         for (c = 0; c < avctx->channels; c++) {

  1290.             js_blocks[0] = 0;

  1291.             js_blocks[1] = 0;

  1292. 

  1293.             get_block_sizes(ctx, div_blocks, &bs_info);

  1294. 

  1295.             // if joint_stereo and block_switching is set, independent decoding

  1296.             // is signaled via the first bit of bs_info

  1297.             if (sconf->joint_stereo && sconf->block_switching)

  1298.                 if (bs_info >> 31)

  1299.                     independent_bs = 2;

  1300. 

  1301.             // if this is the last channel, it has to be decoded independently

  1302.             if (c == avctx->channels - 1)

  1303.                 independent_bs = 1;

  1304. 

  1305.             if (independent_bs) {

  1306.                 if (decode_blocks_ind(ctx, ra_frame, c, div_blocks, js_blocks))

  1307.                     return -1;

  1308. 

  1309.                 independent_bs--;

  1310.             } else {

  1311.                 if (decode_blocks(ctx, ra_frame, c, div_blocks, js_blocks))

  1312.                     return -1;

  1313. 

  1314.                 c++;

  1315.             }

  1316. 

  1317.             // store carryover raw samples

  1318.             memmove(ctx->raw_samples[c] - sconf->max_order,

  1319.                     ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1320.                     sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1321.         }

  1322.     } else { // multi-channel coding

  1323.         ALSBlockData   bd;

  1324.         int            b;

  1325.         int            *reverted_channels = ctx->reverted_channels;

  1326.         unsigned int   offset             = 0;

  1327. 

  1328.         for (c = 0; c < avctx->channels; c++)

  1329.             if (ctx->chan_data[c] < ctx->chan_data_buffer) {

  1330.                 av_log(ctx->avctx, AV_LOG_ERROR, "Invalid channel data!\n");

  1331.                 return -1;

  1332.             }

  1333. 

  1334.         memset(&bd,               0, sizeof(ALSBlockData));

  1335.         memset(reverted_channels, 0, sizeof(*reverted_channels) * avctx->channels);

  1336. 

  1337.         bd.ra_block         = ra_frame;

  1338.         bd.prev_raw_samples = ctx->prev_raw_samples;

  1339. 

  1340.         get_block_sizes(ctx, div_blocks, &bs_info);

  1341. 

  1342.         for (b = 0; b < ctx->num_blocks; b++) {

  1343.             bd.shift_lsbs   = 0;

  1344.             bd.block_length = div_blocks[b];

  1345. 

  1346.             for (c = 0; c < avctx->channels; c++) {

  1347.                 bd.use_ltp     = ctx->use_ltp + c;

  1348.                 bd.ltp_lag     = ctx->ltp_lag + c;

  1349.                 bd.ltp_gain    = ctx->ltp_gain[c];

  1350.                 bd.lpc_cof     = ctx->lpc_cof[c];

  1351.                 bd.quant_cof   = ctx->quant_cof[c];

  1352.                 bd.raw_samples = ctx->raw_samples[c] + offset;

  1353.                 bd.raw_other   = NULL;

  1354. 

  1355.                 read_block(ctx, &bd);

  1356.                 if (read_channel_data(ctx, ctx->chan_data[c], c))

  1357.                     return -1;

  1358.             }

  1359. 

  1360.             for (c = 0; c < avctx->channels; c++)

  1361.                 if (revert_channel_correlation(ctx, &bd, ctx->chan_data,

  1362.                                                reverted_channels, offset, c))

  1363.                     return -1;

  1364. 

  1365.             for (c = 0; c < avctx->channels; c++) {

  1366.                 bd.use_ltp     = ctx->use_ltp + c;

  1367.                 bd.ltp_lag     = ctx->ltp_lag + c;

  1368.                 bd.ltp_gain    = ctx->ltp_gain[c];

  1369.                 bd.lpc_cof     = ctx->lpc_cof[c];

  1370.                 bd.quant_cof   = ctx->quant_cof[c];

  1371.                 bd.raw_samples = ctx->raw_samples[c] + offset;

  1372.                 decode_block(ctx, &bd);

  1373.             }

  1374. 

  1375.             memset(reverted_channels, 0, avctx->channels * sizeof(*reverted_channels));

  1376.             offset      += div_blocks[b];

  1377.             bd.ra_block  = 0;

  1378.         }

  1379. 

  1380.         // store carryover raw samples

  1381.         for (c = 0; c < avctx->channels; c++)

  1382.             memmove(ctx->raw_samples[c] - sconf->max_order,

  1383.                     ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1384.                     sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1385.     }

  1386. 

  1387.     // TODO: read_diff_float_data

  1388. 

  1389.     return 0;

  1390. }

  1391. 

  1392. 

  1393. /** Decode an ALS frame.

  1394.  */

  1395. static int decode_frame(AVCodecContext *avctx,

  1396.                         void *data, int *data_size,

  1397.                         AVPacket *avpkt)

  1398. {

  1399.     ALSDecContext *ctx       = avctx->priv_data;

  1400.     ALSSpecificConfig *sconf = &ctx->sconf;

  1401.     const uint8_t *buffer    = avpkt->data;

  1402.     int buffer_size          = avpkt->size;

  1403.     int invalid_frame, size;

  1404.     unsigned int c, sample, ra_frame, bytes_read, shift;

  1405. 

  1406.     init_get_bits(&ctx->gb, buffer, buffer_size * 8);

  1407. 

  1408.     // In the case that the distance between random access frames is set to zero

  1409.     // (sconf->ra_distance == 0) no frame is treated as a random access frame.

  1410.     // For the first frame, if prediction is used, all samples used from the

  1411.     // previous frame are assumed to be zero.

  1412.     ra_frame = sconf->ra_distance && !(ctx->frame_id % sconf->ra_distance);

  1413. 

  1414.     // the last frame to decode might have a different length

  1415.     if (sconf->samples != 0xFFFFFFFF)

  1416.         ctx->cur_frame_length = FFMIN(sconf->samples - ctx->frame_id * (uint64_t) sconf->frame_length,

  1417.                                       sconf->frame_length);

  1418.     else

  1419.         ctx->cur_frame_length = sconf->frame_length;

  1420. 

  1421.     // decode the frame data

  1422.     if ((invalid_frame = read_frame_data(ctx, ra_frame) < 0))

  1423.         av_log(ctx->avctx, AV_LOG_WARNING,

  1424.                "Reading frame data failed. Skipping RA unit.\n");

  1425. 

  1426.     ctx->frame_id++;

  1427. 

  1428.     // check for size of decoded data

  1429.     size = ctx->cur_frame_length * avctx->channels *

  1430.            (av_get_bits_per_sample_fmt(avctx->sample_fmt) >> 3);

  1431. 

  1432.     if (size > *data_size) {

  1433.         av_log(avctx, AV_LOG_ERROR, "Decoded data exceeds buffer size.\n");

  1434.         return -1;

  1435.     }

  1436. 

  1437.     *data_size = size;

  1438. 

  1439.     // transform decoded frame into output format

  1440.     #define INTERLEAVE_OUTPUT(bps)                                 \

  1441.     {                                                              \

  1442.         int##bps##_t *dest = (int##bps##_t*) data;                 \

  1443.         shift = bps - ctx->avctx->bits_per_raw_sample;             \

  1444.         for (sample = 0; sample < ctx->cur_frame_length; sample++) \

  1445.             for (c = 0; c < avctx->channels; c++)                  \

  1446.                 *dest++ = ctx->raw_samples[c][sample] << shift;    \

  1447.     }

  1448. 

  1449.     if (ctx->avctx->bits_per_raw_sample <= 16) {

  1450.         INTERLEAVE_OUTPUT(16)

  1451.     } else {

  1452.         INTERLEAVE_OUTPUT(32)

  1453.     }

  1454. 

  1455.     // update CRC

  1456.     if (sconf->crc_enabled && avctx->error_recognition >= FF_ER_CAREFUL) {

  1457.         int swap = HAVE_BIGENDIAN != sconf->msb_first;

  1458. 

  1459.         if (ctx->avctx->bits_per_raw_sample == 24) {

  1460.             int32_t *src = data;

  1461. 

  1462.             for (sample = 0;

  1463.                  sample < ctx->cur_frame_length * avctx->channels;

  1464.                  sample++) {

  1465.                 int32_t v;

  1466. 

  1467.                 if (swap)

  1468.                     v = av_bswap32(src[sample]);

  1469.                 else

  1470.                     v = src[sample];

  1471.                 if (!HAVE_BIGENDIAN)

  1472.                     v >>= 8;

  1473. 

  1474.                 ctx->crc = av_crc(ctx->crc_table, ctx->crc, (uint8_t*)(&v), 3);

  1475.             }

  1476.         } else {

  1477.             uint8_t *crc_source;

  1478. 

  1479.             if (swap) {

  1480.                 if (ctx->avctx->bits_per_raw_sample <= 16) {

  1481.                     int16_t *src  = (int16_t*) data;

  1482.                     int16_t *dest = (int16_t*) ctx->crc_buffer;

  1483.                     for (sample = 0;

  1484.                          sample < ctx->cur_frame_length * avctx->channels;

  1485.                          sample++)

  1486.                         *dest++ = av_bswap16(src[sample]);

  1487.                 } else {

  1488.                     ctx->dsp.bswap_buf((uint32_t*)ctx->crc_buffer, data,

  1489.                                        ctx->cur_frame_length * avctx->channels);

  1490.                 }

  1491.                 crc_source = ctx->crc_buffer;

  1492.             } else {

  1493.                 crc_source = data;

  1494.             }

  1495. 

  1496.             ctx->crc = av_crc(ctx->crc_table, ctx->crc, crc_source, size);

  1497.         }

  1498. 

  1499. 

  1500.         // check CRC sums if this is the last frame

  1501.         if (ctx->cur_frame_length != sconf->frame_length &&

  1502.             ctx->crc_org != ctx->crc) {

  1503.             av_log(avctx, AV_LOG_ERROR, "CRC error.\n");

  1504.         }

  1505.     }

  1506. 

  1507. 

  1508.     bytes_read = invalid_frame ? buffer_size :

  1509.                                  (get_bits_count(&ctx->gb) + 7) >> 3;

  1510. 

  1511.     return bytes_read;

  1512. }

  1513. 

  1514. 

  1515. /** Uninitialize the ALS decoder.

  1516.  */

  1517. static av_cold int decode_end(AVCodecContext *avctx)

  1518. {

  1519.     ALSDecContext *ctx = avctx->priv_data;

  1520. 

  1521.     av_freep(&ctx->sconf.chan_pos);

  1522. 

  1523.     ff_bgmc_end(&ctx->bgmc_lut, &ctx->bgmc_lut_status);

  1524. 

  1525.     av_freep(&ctx->use_ltp);

  1526.     av_freep(&ctx->ltp_lag);

  1527.     av_freep(&ctx->ltp_gain);

  1528.     av_freep(&ctx->ltp_gain_buffer);

  1529.     av_freep(&ctx->quant_cof);

  1530.     av_freep(&ctx->lpc_cof);

  1531.     av_freep(&ctx->quant_cof_buffer);

  1532.     av_freep(&ctx->lpc_cof_buffer);

  1533.     av_freep(&ctx->lpc_cof_reversed_buffer);

  1534.     av_freep(&ctx->prev_raw_samples);

  1535.     av_freep(&ctx->raw_samples);

  1536.     av_freep(&ctx->raw_buffer);

  1537.     av_freep(&ctx->chan_data);

  1538.     av_freep(&ctx->chan_data_buffer);

  1539.     av_freep(&ctx->reverted_channels);

  1540. 

  1541.     return 0;

  1542. }

  1543. 

  1544. 

  1545. /** Initialize the ALS decoder.

  1546.  */

  1547. static av_cold int decode_init(AVCodecContext *avctx)

  1548. {

  1549.     unsigned int c;

  1550.     unsigned int channel_size;

  1551.     int num_buffers;

  1552.     ALSDecContext *ctx = avctx->priv_data;

  1553.     ALSSpecificConfig *sconf = &ctx->sconf;

  1554.     ctx->avctx = avctx;

  1555. 

  1556.     if (!avctx->extradata) {

  1557.         av_log(avctx, AV_LOG_ERROR, "Missing required ALS extradata.\n");

  1558.         return -1;

  1559.     }

  1560. 

  1561.     if (read_specific_config(ctx)) {

  1562.         av_log(avctx, AV_LOG_ERROR, "Reading ALSSpecificConfig failed.\n");

  1563.         decode_end(avctx);

  1564.         return -1;

  1565.     }

  1566. 

  1567.     if (check_specific_config(ctx)) {

  1568.         decode_end(avctx);

  1569.         return -1;

  1570.     }

  1571. 

  1572.     if (sconf->bgmc)

  1573.         ff_bgmc_init(avctx, &ctx->bgmc_lut, &ctx->bgmc_lut_status);

  1574. 

  1575.     if (sconf->floating) {

  1576.         avctx->sample_fmt          = AV_SAMPLE_FMT_FLT;

  1577.         avctx->bits_per_raw_sample = 32;

  1578.     } else {

  1579.         avctx->sample_fmt          = sconf->resolution > 1

  1580.                                      ? AV_SAMPLE_FMT_S32 : AV_SAMPLE_FMT_S16;

  1581.         avctx->bits_per_raw_sample = (sconf->resolution + 1) * 8;

  1582.     }

  1583. 

  1584.     // set maximum Rice parameter for progressive decoding based on resolution

  1585.     // This is not specified in 14496-3 but actually done by the reference

  1586.     // codec RM22 revision 2.

  1587.     ctx->s_max = sconf->resolution > 1 ? 31 : 15;

  1588. 

  1589.     // set lag value for long-term prediction

  1590.     ctx->ltp_lag_length = 8 + (avctx->sample_rate >=  96000) +

  1591.                               (avctx->sample_rate >= 192000);

  1592. 

  1593.     // allocate quantized parcor coefficient buffer

  1594.     num_buffers = sconf->mc_coding ? avctx->channels : 1;

  1595. 

  1596.     ctx->quant_cof        = av_malloc(sizeof(*ctx->quant_cof) * num_buffers);

  1597.     ctx->lpc_cof          = av_malloc(sizeof(*ctx->lpc_cof)   * num_buffers);

  1598.     ctx->quant_cof_buffer = av_malloc(sizeof(*ctx->quant_cof_buffer) *

  1599.                                       num_buffers * sconf->max_order);

  1600.     ctx->lpc_cof_buffer   = av_malloc(sizeof(*ctx->lpc_cof_buffer) *

  1601.                                       num_buffers * sconf->max_order);

  1602.     ctx->lpc_cof_reversed_buffer = av_malloc(sizeof(*ctx->lpc_cof_buffer) *

  1603.                                              sconf->max_order);

  1604. 

  1605.     if (!ctx->quant_cof              || !ctx->lpc_cof        ||

  1606.         !ctx->quant_cof_buffer       || !ctx->lpc_cof_buffer ||

  1607.         !ctx->lpc_cof_reversed_buffer) {

  1608.         av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1609.         return AVERROR(ENOMEM);

  1610.     }

  1611. 

  1612.     // assign quantized parcor coefficient buffers

  1613.     for (c = 0; c < num_buffers; c++) {

  1614.         ctx->quant_cof[c] = ctx->quant_cof_buffer + c * sconf->max_order;

  1615.         ctx->lpc_cof[c]   = ctx->lpc_cof_buffer   + c * sconf->max_order;

  1616.     }

  1617. 

  1618.     // allocate and assign lag and gain data buffer for ltp mode

  1619.     ctx->use_ltp         = av_mallocz(sizeof(*ctx->use_ltp)  * num_buffers);

  1620.     ctx->ltp_lag         = av_malloc (sizeof(*ctx->ltp_lag)  * num_buffers);

  1621.     ctx->ltp_gain        = av_malloc (sizeof(*ctx->ltp_gain) * num_buffers);

  1622.     ctx->ltp_gain_buffer = av_malloc (sizeof(*ctx->ltp_gain_buffer) *

  1623.                                       num_buffers * 5);

  1624. 

  1625.     if (!ctx->use_ltp  || !ctx->ltp_lag ||

  1626.         !ctx->ltp_gain || !ctx->ltp_gain_buffer) {

  1627.         av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1628.         decode_end(avctx);

  1629.         return AVERROR(ENOMEM);

  1630.     }

  1631. 

  1632.     for (c = 0; c < num_buffers; c++)

  1633.         ctx->ltp_gain[c] = ctx->ltp_gain_buffer + c * 5;

  1634. 

  1635.     // allocate and assign channel data buffer for mcc mode

  1636.     if (sconf->mc_coding) {

  1637.         ctx->chan_data_buffer  = av_malloc(sizeof(*ctx->chan_data_buffer) *

  1638.                                            num_buffers * num_buffers);

  1639.         ctx->chan_data         = av_malloc(sizeof(*ctx->chan_data) *

  1640.                                            num_buffers);

  1641.         ctx->reverted_channels = av_malloc(sizeof(*ctx->reverted_channels) *

  1642.                                            num_buffers);

  1643. 

  1644.         if (!ctx->chan_data_buffer || !ctx->chan_data || !ctx->reverted_channels) {

  1645.             av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1646.             decode_end(avctx);

  1647.             return AVERROR(ENOMEM);

  1648.         }

  1649. 

  1650.         for (c = 0; c < num_buffers; c++)

  1651.             ctx->chan_data[c] = ctx->chan_data_buffer + c * num_buffers;

  1652.     } else {

  1653.         ctx->chan_data         = NULL;

  1654.         ctx->chan_data_buffer  = NULL;

  1655.         ctx->reverted_channels = NULL;

  1656.     }

  1657. 

  1658.     avctx->frame_size = sconf->frame_length;

  1659.     channel_size      = sconf->frame_length + sconf->max_order;

  1660. 

  1661.     ctx->prev_raw_samples = av_malloc (sizeof(*ctx->prev_raw_samples) * sconf->max_order);

  1662.     ctx->raw_buffer       = av_mallocz(sizeof(*ctx->     raw_buffer)  * avctx->channels * channel_size);

  1663.     ctx->raw_samples      = av_malloc (sizeof(*ctx->     raw_samples) * avctx->channels);

  1664. 

  1665.     // allocate previous raw sample buffer

  1666.     if (!ctx->prev_raw_samples || !ctx->raw_buffer|| !ctx->raw_samples) {

  1667.         av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1668.         decode_end(avctx);

  1669.         return AVERROR(ENOMEM);

  1670.     }

  1671. 

  1672.     // assign raw samples buffers

  1673.     ctx->raw_samples[0] = ctx->raw_buffer + sconf->max_order;

  1674.     for (c = 1; c < avctx->channels; c++)

  1675.         ctx->raw_samples[c] = ctx->raw_samples[c - 1] + channel_size;

  1676. 

  1677.     // allocate crc buffer

  1678.     if (HAVE_BIGENDIAN != sconf->msb_first && sconf->crc_enabled &&

  1679.         avctx->error_recognition >= FF_ER_CAREFUL) {

  1680.         ctx->crc_buffer = av_malloc(sizeof(*ctx->crc_buffer) *

  1681.                                     ctx->cur_frame_length *

  1682.                                     avctx->channels *

  1683.                                     (av_get_bits_per_sample_fmt(avctx->sample_fmt) >> 3));

  1684.         if (!ctx->crc_buffer) {

  1685.             av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1686.             decode_end(avctx);

  1687.             return AVERROR(ENOMEM);

  1688.         }

  1689.     }

  1690. 

  1691.     dsputil_init(&ctx->dsp, avctx);

  1692. 

  1693.     return 0;

  1694. }

  1695. 

  1696. 

  1697. /** Flush (reset) the frame ID after seeking.

  1698.  */

  1699. static av_cold void flush(AVCodecContext *avctx)

  1700. {

  1701.     ALSDecContext *ctx = avctx->priv_data;

  1702. 

  1703.     ctx->frame_id = 0;

  1704. }

  1705. 

  1706. 

  1707. AVCodec als_decoder = {

  1708.     "als",

  1709.     AVMEDIA_TYPE_AUDIO,

  1710.     CODEC_ID_MP4ALS,

  1711.     sizeof(ALSDecContext),

  1712.     decode_init,

  1713.     NULL,

  1714.     decode_end,

  1715.     decode_frame,

  1716.     .flush = flush,

  1717.     .capabilities = CODEC_CAP_SUBFRAMES,

  1718.     .long_name = NULL_IF_CONFIG_SMALL("MPEG-4 Audio Lossless Coding (ALS)"),

  1719. };