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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 Libav.

  6.  *

  7.  * Libav 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.  * Libav 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 Libav; 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 "internal.h"

  40. #include "libavutil/samplefmt.h"

  41. #include "libavutil/crc.h"

  42. 

  43. #include <stdint.h>

  44. 

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

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

  47.  *  by the encoder and stored in ALSSpecificConfig.

  48.  */

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

  50.     { {-52, 4}, {-29, 5}, {-31, 4}, { 19, 4}, {-16, 4},

  51.       { 12, 3}, { -7, 3}, {  9, 3}, { -5, 3}, {  6, 3},

  52.       { -4, 3}, {  3, 3}, { -3, 2}, {  3, 2}, { -2, 2},

  53.       {  3, 2}, { -1, 2}, {  2, 2}, { -1, 2}, {  2, 2} },

  54.     { {-58, 3}, {-42, 4}, {-46, 4}, { 37, 5}, {-36, 4},

  55.       { 29, 4}, {-29, 4}, { 25, 4}, {-23, 4}, { 20, 4},

  56.       {-17, 4}, { 16, 4}, {-12, 4}, { 12, 3}, {-10, 4},

  57.       {  7, 3}, { -4, 4}, {  3, 3}, { -1, 3}, {  1, 3} },

  58.     { {-59, 3}, {-45, 5}, {-50, 4}, { 38, 4}, {-39, 4},

  59.       { 32, 4}, {-30, 4}, { 25, 3}, {-23, 3}, { 20, 3},

  60.       {-20, 3}, { 16, 3}, {-13, 3}, { 10, 3}, { -7, 3},

  61.       {  3, 3}, {  0, 3}, { -1, 3}, {  2, 3}, { -1, 2} }

  62. };

  63. 

  64. 

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

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

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

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

  69.  */

  70. static const int16_t parcor_scaled_values[] = {

  71.     -1048544 / 32, -1048288 / 32, -1047776 / 32, -1047008 / 32,

  72.     -1045984 / 32, -1044704 / 32, -1043168 / 32, -1041376 / 32,

  73.     -1039328 / 32, -1037024 / 32, -1034464 / 32, -1031648 / 32,

  74.     -1028576 / 32, -1025248 / 32, -1021664 / 32, -1017824 / 32,

  75.     -1013728 / 32, -1009376 / 32, -1004768 / 32,  -999904 / 32,

  76.      -994784 / 32,  -989408 / 32,  -983776 / 32,  -977888 / 32,

  77.      -971744 / 32,  -965344 / 32,  -958688 / 32,  -951776 / 32,

  78.      -944608 / 32,  -937184 / 32,  -929504 / 32,  -921568 / 32,

  79.      -913376 / 32,  -904928 / 32,  -896224 / 32,  -887264 / 32,

  80.      -878048 / 32,  -868576 / 32,  -858848 / 32,  -848864 / 32,

  81.      -838624 / 32,  -828128 / 32,  -817376 / 32,  -806368 / 32,

  82.      -795104 / 32,  -783584 / 32,  -771808 / 32,  -759776 / 32,

  83.      -747488 / 32,  -734944 / 32,  -722144 / 32,  -709088 / 32,

  84.      -695776 / 32,  -682208 / 32,  -668384 / 32,  -654304 / 32,

  85.      -639968 / 32,  -625376 / 32,  -610528 / 32,  -595424 / 32,

  86.      -580064 / 32,  -564448 / 32,  -548576 / 32,  -532448 / 32,

  87.      -516064 / 32,  -499424 / 32,  -482528 / 32,  -465376 / 32,

  88.      -447968 / 32,  -430304 / 32,  -412384 / 32,  -394208 / 32,

  89.      -375776 / 32,  -357088 / 32,  -338144 / 32,  -318944 / 32,

  90.      -299488 / 32,  -279776 / 32,  -259808 / 32,  -239584 / 32,

  91.      -219104 / 32,  -198368 / 32,  -177376 / 32,  -156128 / 32,

  92.      -134624 / 32,  -112864 / 32,   -90848 / 32,   -68576 / 32,

  93.       -46048 / 32,   -23264 / 32,     -224 / 32,    23072 / 32,

  94.        46624 / 32,    70432 / 32,    94496 / 32,   118816 / 32,

  95.       143392 / 32,   168224 / 32,   193312 / 32,   218656 / 32,

  96.       244256 / 32,   270112 / 32,   296224 / 32,   322592 / 32,

  97.       349216 / 32,   376096 / 32,   403232 / 32,   430624 / 32,

  98.       458272 / 32,   486176 / 32,   514336 / 32,   542752 / 32,

  99.       571424 / 32,   600352 / 32,   629536 / 32,   658976 / 32,

  100.       688672 / 32,   718624 / 32,   748832 / 32,   779296 / 32,

  101.       810016 / 32,   840992 / 32,   872224 / 32,   903712 / 32,

  102.       935456 / 32,   967456 / 32,   999712 / 32,  1032224 / 32

  103. };

  104. 

  105. 

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

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

  108.  */

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

  110.     { 0,  8, 16,  24},

  111.     {32, 40, 48,  56},

  112.     {64, 70, 76,  82},

  113.     {88, 92, 96, 100}

  114. };

  115. 

  116. 

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

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

  119.  */

  120. static const int16_t mcc_weightings[] = {

  121.     204,  192,  179,  166,  153,  140,  128,  115,

  122.     102,   89,   76,   64,   51,   38,   25,   12,

  123.       0,  -12,  -25,  -38,  -51,  -64,  -76,  -89,

  124.    -102, -115, -128, -140, -153, -166, -179, -192

  125. };

  126. 

  127. 

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

  129.  */

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

  131.     { 74, 44, 25, 13,  7, 3},

  132.     { 68, 42, 24, 13,  7, 3},

  133.     { 58, 39, 23, 13,  7, 3},

  134.     {126, 70, 37, 19, 10, 5},

  135.     {132, 70, 37, 20, 10, 5},

  136.     {124, 70, 38, 20, 10, 5},

  137.     {120, 69, 37, 20, 11, 5},

  138.     {116, 67, 37, 20, 11, 5},

  139.     {108, 66, 36, 20, 10, 5},

  140.     {102, 62, 36, 20, 10, 5},

  141.     { 88, 58, 34, 19, 10, 5},

  142.     {162, 89, 49, 25, 13, 7},

  143.     {156, 87, 49, 26, 14, 7},

  144.     {150, 86, 47, 26, 14, 7},

  145.     {142, 84, 47, 26, 14, 7},

  146.     {131, 79, 46, 26, 14, 7}

  147. };

  148. 

  149. 

  150. enum RA_Flag {

  151.     RA_FLAG_NONE,

  152.     RA_FLAG_FRAMES,

  153.     RA_FLAG_HEADER

  154. };

  155. 

  156. 

  157. typedef struct {

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  180. } ALSSpecificConfig;

  181. 

  182. 

  183. typedef struct {

  184.     int stop_flag;

  185.     int master_channel;

  186.     int time_diff_flag;

  187.     int time_diff_sign;

  188.     int time_diff_index;

  189.     int weighting[6];

  190. } ALSChannelData;

  191. 

  192. 

  193. typedef struct {

  194.     AVCodecContext *avctx;

  195.     AVFrame frame;

  196.     ALSSpecificConfig sconf;

  197.     GetBitContext gb;

  198.     DSPContext dsp;

  199.     const AVCRC *crc_table;

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

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

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

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

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

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

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

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

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

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

  210.     int *const_block;               ///< contains const_block flags for all channels

  211.     unsigned int *shift_lsbs;       ///< contains shift_lsbs flags for all channels

  212.     unsigned int *opt_order;        ///< contains opt_order flags for all channels

  213.     int *store_prev_samples;        ///< contains store_prev_samples flags for all channels

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  230. } ALSDecContext;

  231. 

  232. 

  233. typedef struct {

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  249. } ALSBlockData;

  250. 

  251. 

  252. static av_cold void dprint_specific_config(ALSDecContext *ctx)

  253. {

  254. #ifdef DEBUG

  255.     AVCodecContext *avctx    = ctx->avctx;

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

  257. 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  276. #endif

  277. }

  278. 

  279. 

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

  281.  */

  282. static av_cold int read_specific_config(ALSDecContext *ctx)

  283. {

  284.     GetBitContext gb;

  285.     uint64_t ht_size;

  286.     int i, config_offset;

  287.     MPEG4AudioConfig m4ac;

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

  289.     AVCodecContext *avctx    = ctx->avctx;

  290.     uint32_t als_id, header_size, trailer_size;

  291. 

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

  293. 

  294.     config_offset = avpriv_mpeg4audio_get_config(&m4ac, avctx->extradata,

  295.                                                  avctx->extradata_size * 8, 1);

  296. 

  297.     if (config_offset < 0)

  298.         return -1;

  299. 

  300.     skip_bits_long(&gb, config_offset);

  301. 

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

  303.         return -1;

  304. 

  305.     // read the fixed items

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

  307.     avctx->sample_rate          = m4ac.sample_rate;

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

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

  310.     avctx->channels             = m4ac.channels;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  334. 

  335. 

  336.     // check for ALSSpecificConfig struct

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

  338.         return -1;

  339. 

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

  341. 

  342.     // read channel config

  343.     if (sconf->chan_config)

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

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

  346. 

  347. 

  348.     // read channel sorting

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

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

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

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

  353.             return -1;

  354. 

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

  356.             return AVERROR(ENOMEM);

  357. 

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

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

  360. 

  361.         align_get_bits(&gb);

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

  363.     } else {

  364.         sconf->chan_sort = 0;

  365.     }

  366. 

  367. 

  368.     // read fixed header and trailer sizes,

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

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

  371.         return -1;

  372. 

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

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

  375.     if (header_size  == 0xFFFFFFFF)

  376.         header_size  = 0;

  377.     if (trailer_size == 0xFFFFFFFF)

  378.         trailer_size = 0;

  379. 

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

  381. 

  382. 

  383.     // skip the header and trailer data

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

  385.         return -1;

  386. 

  387.     if (ht_size > INT32_MAX)

  388.         return -1;

  389. 

  390.     skip_bits_long(&gb, ht_size);

  391. 

  392. 

  393.     // initialize CRC calculation

  394.     if (sconf->crc_enabled) {

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

  396.             return -1;

  397. 

  398.         if (avctx->err_recognition & AV_EF_CRCCHECK) {

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

  400.             ctx->crc       = 0xFFFFFFFF;

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

  402.         } else

  403.             skip_bits_long(&gb, 32);

  404.     }

  405. 

  406. 

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

  408. 

  409.     dprint_specific_config(ctx);

  410. 

  411.     return 0;

  412. }

  413. 

  414. 

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

  416.  */

  417. static int check_specific_config(ALSDecContext *ctx)

  418. {

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

  420.     int error = 0;

  421. 

  422.     // report unsupported feature and set error value

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

  424.     {                                                   \

  425.         if (cond) {                                     \

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

  427.             error = errval;                             \

  428.         }                                               \

  429.     }

  430. 

  431.     MISSING_ERR(sconf->floating,  "Floating point decoding",     AVERROR_PATCHWELCOME);

  432.     MISSING_ERR(sconf->rlslms,    "Adaptive RLS-LMS prediction", AVERROR_PATCHWELCOME);

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

  434. 

  435.     return error;

  436. }

  437. 

  438. 

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

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

  441.  */

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

  443.                           unsigned int div, unsigned int **div_blocks,

  444.                           unsigned int *num_blocks)

  445. {

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

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

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

  449.         n   *= 2;

  450.         div += 1;

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

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

  453.     } else {

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

  455.         // (bit implicitly not set)

  456.         **div_blocks = div;

  457.         (*div_blocks)++;

  458.         (*num_blocks)++;

  459.     }

  460. }

  461. 

  462. 

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

  464.  */

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

  466. {

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

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

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

  470. 

  471.     if (k > 1) {

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

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

  474.     } else if (!k) {

  475.         q >>= 1;

  476.     }

  477.     return r ? q : ~q;

  478. }

  479. 

  480. 

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

  482.  */

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

  484. {

  485.     int i, j;

  486. 

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

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

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

  490.         cof[i]  += tmp1;

  491.     }

  492.     if (i == j)

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

  494. 

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

  496. }

  497. 

  498. 

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

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

  501.  *  actual number of samples.

  502.  */

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

  504.                             uint32_t *bs_info)

  505. {

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

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

  508.     unsigned int *ptr_div_blocks = div_blocks;

  509.     unsigned int b;

  510. 

  511.     if (sconf->block_switching) {

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

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

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

  515.     }

  516. 

  517.     ctx->num_blocks = 0;

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

  519. 

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

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

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

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

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

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

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

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

  528.     // codec RM22 revision 2.

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

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

  531.     // of 14496-3.

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

  533.     // frame.

  534. 

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

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

  537. 

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

  539.         unsigned int remaining = ctx->cur_frame_length;

  540. 

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

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

  543.                 div_blocks[b] = remaining;

  544.                 ctx->num_blocks = b + 1;

  545.                 break;

  546.             }

  547. 

  548.             remaining -= div_blocks[b];

  549.         }

  550.     }

  551. }

  552. 

  553. 

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

  555.  */

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

  557. {

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

  559.     AVCodecContext *avctx    = ctx->avctx;

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

  561. 

  562.     *bd->raw_samples = 0;

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

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

  565. 

  566.     // skip 5 reserved bits

  567.     skip_bits(gb, 5);

  568. 

  569.     if (*bd->const_block) {

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

  571.         *bd->raw_samples = get_sbits_long(gb, const_val_bits);

  572.     }

  573. 

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

  575.     *bd->const_block = 1;

  576. }

  577. 

  578. 

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

  580.  */

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

  582. {

  583.     int      smp = bd->block_length - 1;

  584.     int32_t  val = *bd->raw_samples;

  585.     int32_t *dst = bd->raw_samples + 1;

  586. 

  587.     // write raw samples into buffer

  588.     for (; smp; smp--)

  589.         *dst++ = val;

  590. }

  591. 

  592. 

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

  594.  */

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

  596. {

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

  598.     AVCodecContext *avctx    = ctx->avctx;

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

  600.     unsigned int k;

  601.     unsigned int s[8];

  602.     unsigned int sx[8];

  603.     unsigned int sub_blocks, log2_sub_blocks, sb_length;

  604.     unsigned int start      = 0;

  605.     unsigned int opt_order;

  606.     int          sb;

  607.     int32_t      *quant_cof = bd->quant_cof;

  608.     int32_t      *current_res;

  609. 

  610. 

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

  612.     *bd->const_block = 0;

  613. 

  614.     *bd->opt_order  = 1;

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

  616. 

  617.     opt_order       = *bd->opt_order;

  618. 

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

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

  621.         log2_sub_blocks = 0;

  622.     } else {

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

  624.             log2_sub_blocks = get_bits(gb, 2);

  625.         else

  626.             log2_sub_blocks = 2 * get_bits1(gb);

  627.     }

  628. 

  629.     sub_blocks = 1 << log2_sub_blocks;

  630. 

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

  632.     // block_length must be evenly divisible by sub_blocks

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

  634.         av_log(avctx, AV_LOG_WARNING,

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

  636.         return -1;

  637.     }

  638. 

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

  640. 

  641.     if (sconf->bgmc) {

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

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

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

  645. 

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

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

  648.             s [k] >>= 4;

  649.         }

  650.     } else {

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

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

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

  654.     }

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

  656.         if (s[k] > 32) {

  657.             av_log(avctx, AV_LOG_ERROR, "k invalid for rice code.\n");

  658.             return AVERROR_INVALIDDATA;

  659.         }

  660. 

  661.     if (get_bits1(gb))

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

  663. 

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

  665. 

  666. 

  667.     if (!sconf->rlslms) {

  668.         if (sconf->adapt_order) {

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

  670.                                                 2, sconf->max_order + 1));

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

  672.             if (*bd->opt_order > sconf->max_order) {

  673.                 *bd->opt_order = sconf->max_order;

  674.                 av_log(avctx, AV_LOG_ERROR, "Predictor order too large!\n");

  675.                 return AVERROR_INVALIDDATA;

  676.             }

  677.         } else {

  678.             *bd->opt_order = sconf->max_order;

  679.         }

  680. 

  681.         opt_order = *bd->opt_order;

  682. 

  683.         if (opt_order) {

  684.             int add_base;

  685. 

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

  687.                 add_base = 0x7F;

  688. 

  689.                 // read coefficient 0

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

  691. 

  692.                 // read coefficient 1

  693.                 if (opt_order > 1)

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

  695. 

  696.                 // read coefficients 2 to opt_order

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

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

  699.             } else {

  700.                 int k_max;

  701.                 add_base = 1;

  702. 

  703.                 // read coefficient 0 to 19

  704.                 k_max = FFMIN(opt_order, 20);

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

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

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

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

  709.                     if (quant_cof[k] < -64 || quant_cof[k] > 63) {

  710.                         av_log(avctx, AV_LOG_ERROR, "quant_cof %d is out of range\n", quant_cof[k]);

  711.                         return AVERROR_INVALIDDATA;

  712.                     }

  713.                 }

  714. 

  715.                 // read coefficients 20 to 126

  716.                 k_max = FFMIN(opt_order, 127);

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

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

  719. 

  720.                 // read coefficients 127 to opt_order

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

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

  723. 

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

  725. 

  726.                 if (opt_order > 1)

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

  728.             }

  729. 

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

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

  732.         }

  733.     }

  734. 

  735.     // read LTP gain and lag values

  736.     if (sconf->long_term_prediction) {

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

  738. 

  739.         if (*bd->use_ltp) {

  740.             int r, c;

  741. 

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

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

  744. 

  745.             r                 = get_unary(gb, 0, 3);

  746.             c                 = get_bits(gb, 2);

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

  748. 

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

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

  751. 

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

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

  754.         }

  755.     }

  756. 

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

  758.     if (bd->ra_block) {

  759.         if (opt_order)

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

  761.         if (opt_order > 1)

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

  763.         if (opt_order > 2)

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

  765. 

  766.         start = FFMIN(opt_order, 3);

  767.     }

  768. 

  769.     // read all residuals

  770.     if (sconf->bgmc) {

  771.         int          delta[8];

  772.         unsigned int k    [8];

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

  774. 

  775.         // read most significant bits

  776.         unsigned int high;

  777.         unsigned int low;

  778.         unsigned int value;

  779. 

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

  781. 

  782.         current_res = bd->raw_samples + start;

  783. 

  784.         for (sb = 0; sb < sub_blocks; sb++) {

  785.             unsigned int sb_len  = sb_length - (sb ? 0 : start);

  786. 

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

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

  789. 

  790.             ff_bgmc_decode(gb, sb_len, current_res,

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

  792. 

  793.             current_res += sb_len;

  794.         }

  795. 

  796.         ff_bgmc_decode_end(gb);

  797. 

  798. 

  799.         // read least significant bits and tails

  800.         current_res = bd->raw_samples + start;

  801. 

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

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

  804.             unsigned int cur_k         = k[sb];

  805.             unsigned int cur_s         = s[sb];

  806. 

  807.             for (; start < sb_length; start++) {

  808.                 int32_t res = *current_res;

  809. 

  810.                 if (res == cur_tail_code) {

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

  812.                                           << (5 - delta[sb]);

  813. 

  814.                     res = decode_rice(gb, cur_s);

  815. 

  816.                     if (res >= 0) {

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

  818.                     } else {

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

  820.                     }

  821.                 } else {

  822.                     if (res > cur_tail_code)

  823.                         res--;

  824. 

  825.                     if (res & 1)

  826.                         res = -res;

  827. 

  828.                     res >>= 1;

  829. 

  830.                     if (cur_k) {

  831.                         res <<= cur_k;

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

  833.                     }

  834.                 }

  835. 

  836.                 *current_res++ = res;

  837.             }

  838.         }

  839.     } else {

  840.         current_res = bd->raw_samples + start;

  841. 

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

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

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

  845.      }

  846. 

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

  848.         align_get_bits(gb);

  849. 

  850.     return 0;

  851. }

  852. 

  853. 

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

  855.  */

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

  857. {

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

  859.     unsigned int block_length = bd->block_length;

  860.     unsigned int smp = 0;

  861.     unsigned int k;

  862.     int opt_order             = *bd->opt_order;

  863.     int sb;

  864.     int64_t y;

  865.     int32_t *quant_cof        = bd->quant_cof;

  866.     int32_t *lpc_cof          = bd->lpc_cof;

  867.     int32_t *raw_samples      = bd->raw_samples;

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

  869.     int32_t *lpc_cof_reversed = ctx->lpc_cof_reversed_buffer;

  870. 

  871.     // reverse long-term prediction

  872.     if (*bd->use_ltp) {

  873.         int ltp_smp;

  874. 

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

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

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

  878.             int end    = center + 3;

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

  880.             int base;

  881. 

  882.             y = 1 << 6;

  883. 

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

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

  886. 

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

  888.         }

  889.     }

  890. 

  891.     // reconstruct all samples from residuals

  892.     if (bd->ra_block) {

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

  894.             y = 1 << 19;

  895. 

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

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

  898. 

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

  900.             parcor_to_lpc(smp, quant_cof, lpc_cof);

  901.         }

  902.     } else {

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

  904.             parcor_to_lpc(k, quant_cof, lpc_cof);

  905. 

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

  907.         if (*bd->store_prev_samples)

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

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

  910. 

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

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

  913.             int32_t *left, *right;

  914. 

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

  916.                 left  = raw_samples;

  917.                 right = bd->raw_other;

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

  919.                 left  = bd->raw_other;

  920.                 right = raw_samples;

  921.             }

  922. 

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

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

  925.         }

  926. 

  927.         // reconstruct shifted signal

  928.         if (*bd->shift_lsbs)

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

  930.                 raw_samples[sb] >>= *bd->shift_lsbs;

  931.     }

  932. 

  933.     // reverse linear prediction coefficients for efficiency

  934.     lpc_cof = lpc_cof + opt_order;

  935. 

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

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

  938. 

  939.     // reconstruct raw samples

  940.     raw_samples = bd->raw_samples + smp;

  941.     lpc_cof     = lpc_cof_reversed + opt_order;

  942. 

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

  944.         y = 1 << 19;

  945. 

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

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

  948. 

  949.         *raw_samples -= y >> 20;

  950.     }

  951. 

  952.     raw_samples = bd->raw_samples;

  953. 

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

  955.     if (*bd->store_prev_samples)

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

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

  958. 

  959.     return 0;

  960. }

  961. 

  962. 

  963. /** Read the block data.

  964.  */

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

  966. {

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

  968. 

  969.     *bd->shift_lsbs = 0;

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

  971.     if (get_bits1(gb)) {

  972.         if (read_var_block_data(ctx, bd))

  973.             return -1;

  974.     } else {

  975.         read_const_block_data(ctx, bd);

  976.     }

  977. 

  978.     return 0;

  979. }

  980. 

  981. 

  982. /** Decode the block data.

  983.  */

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

  985. {

  986.     unsigned int smp;

  987. 

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

  989.     if (*bd->const_block)

  990.         decode_const_block_data(ctx, bd);

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

  992.         return -1;

  993. 

  994.     // TODO: read RLSLMS extension data

  995. 

  996.     if (*bd->shift_lsbs)

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

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

  999. 

  1000.     return 0;

  1001. }

  1002. 

  1003. 

  1004. /** Read and decode block data successively.

  1005.  */

  1006. static int read_decode_block(ALSDecContext *ctx, ALSBlockData *bd)

  1007. {

  1008.     int ret;

  1009. 

  1010.     ret = read_block(ctx, bd);

  1011. 

  1012.     if (ret)

  1013.         return ret;

  1014. 

  1015.     ret = decode_block(ctx, bd);

  1016. 

  1017.     return ret;

  1018. }

  1019. 

  1020. 

  1021. /** Compute the number of samples left to decode for the current frame and

  1022.  *  sets these samples to zero.

  1023.  */

  1024. static void zero_remaining(unsigned int b, unsigned int b_max,

  1025.                            const unsigned int *div_blocks, int32_t *buf)

  1026. {

  1027.     unsigned int count = 0;

  1028. 

  1029.     for (; b < b_max; b++)

  1030.         count += div_blocks[b];

  1031. 

  1032.     if (count)

  1033.         memset(buf, 0, sizeof(*buf) * count);

  1034. }

  1035. 

  1036. 

  1037. /** Decode blocks independently.

  1038.  */

  1039. static int decode_blocks_ind(ALSDecContext *ctx, unsigned int ra_frame,

  1040.                              unsigned int c, const unsigned int *div_blocks,

  1041.                              unsigned int *js_blocks)

  1042. {

  1043.     unsigned int b;

  1044.     ALSBlockData bd = { 0 };

  1045. 

  1046.     bd.ra_block         = ra_frame;

  1047.     bd.const_block      = ctx->const_block;

  1048.     bd.shift_lsbs       = ctx->shift_lsbs;

  1049.     bd.opt_order        = ctx->opt_order;

  1050.     bd.store_prev_samples = ctx->store_prev_samples;

  1051.     bd.use_ltp          = ctx->use_ltp;

  1052.     bd.ltp_lag          = ctx->ltp_lag;

  1053.     bd.ltp_gain         = ctx->ltp_gain[0];

  1054.     bd.quant_cof        = ctx->quant_cof[0];

  1055.     bd.lpc_cof          = ctx->lpc_cof[0];

  1056.     bd.prev_raw_samples = ctx->prev_raw_samples;

  1057.     bd.raw_samples      = ctx->raw_samples[c];

  1058. 

  1059. 

  1060.     for (b = 0; b < ctx->num_blocks; b++) {

  1061.         bd.block_length     = div_blocks[b];

  1062. 

  1063.         if (read_decode_block(ctx, &bd)) {

  1064.             // damaged block, write zero for the rest of the frame

  1065.             zero_remaining(b, ctx->num_blocks, div_blocks, bd.raw_samples);

  1066.             return -1;

  1067.         }

  1068.         bd.raw_samples += div_blocks[b];

  1069.         bd.ra_block     = 0;

  1070.     }

  1071. 

  1072.     return 0;

  1073. }

  1074. 

  1075. 

  1076. /** Decode blocks dependently.

  1077.  */

  1078. static int decode_blocks(ALSDecContext *ctx, unsigned int ra_frame,

  1079.                          unsigned int c, const unsigned int *div_blocks,

  1080.                          unsigned int *js_blocks)

  1081. {

  1082.     ALSSpecificConfig *sconf = &ctx->sconf;

  1083.     unsigned int offset = 0;

  1084.     unsigned int b;

  1085.     ALSBlockData bd[2] = { { 0 } };

  1086. 

  1087.     bd[0].ra_block         = ra_frame;

  1088.     bd[0].const_block      = ctx->const_block;

  1089.     bd[0].shift_lsbs       = ctx->shift_lsbs;

  1090.     bd[0].opt_order        = ctx->opt_order;

  1091.     bd[0].store_prev_samples = ctx->store_prev_samples;

  1092.     bd[0].use_ltp          = ctx->use_ltp;

  1093.     bd[0].ltp_lag          = ctx->ltp_lag;

  1094.     bd[0].ltp_gain         = ctx->ltp_gain[0];

  1095.     bd[0].quant_cof        = ctx->quant_cof[0];

  1096.     bd[0].lpc_cof          = ctx->lpc_cof[0];

  1097.     bd[0].prev_raw_samples = ctx->prev_raw_samples;

  1098.     bd[0].js_blocks        = *js_blocks;

  1099. 

  1100.     bd[1].ra_block         = ra_frame;

  1101.     bd[1].const_block      = ctx->const_block;

  1102.     bd[1].shift_lsbs       = ctx->shift_lsbs;

  1103.     bd[1].opt_order        = ctx->opt_order;

  1104.     bd[1].store_prev_samples = ctx->store_prev_samples;

  1105.     bd[1].use_ltp          = ctx->use_ltp;

  1106.     bd[1].ltp_lag          = ctx->ltp_lag;

  1107.     bd[1].ltp_gain         = ctx->ltp_gain[0];

  1108.     bd[1].quant_cof        = ctx->quant_cof[0];

  1109.     bd[1].lpc_cof          = ctx->lpc_cof[0];

  1110.     bd[1].prev_raw_samples = ctx->prev_raw_samples;

  1111.     bd[1].js_blocks        = *(js_blocks + 1);

  1112. 

  1113.     // decode all blocks

  1114.     for (b = 0; b < ctx->num_blocks; b++) {

  1115.         unsigned int s;

  1116. 

  1117.         bd[0].block_length = div_blocks[b];

  1118.         bd[1].block_length = div_blocks[b];

  1119. 

  1120.         bd[0].raw_samples  = ctx->raw_samples[c    ] + offset;

  1121.         bd[1].raw_samples  = ctx->raw_samples[c + 1] + offset;

  1122. 

  1123.         bd[0].raw_other    = bd[1].raw_samples;

  1124.         bd[1].raw_other    = bd[0].raw_samples;

  1125. 

  1126.         if(read_decode_block(ctx, &bd[0]) || read_decode_block(ctx, &bd[1])) {

  1127.             // damaged block, write zero for the rest of the frame

  1128.             zero_remaining(b, ctx->num_blocks, div_blocks, bd[0].raw_samples);

  1129.             zero_remaining(b, ctx->num_blocks, div_blocks, bd[1].raw_samples);

  1130.             return -1;

  1131.         }

  1132. 

  1133.         // reconstruct joint-stereo blocks

  1134.         if (bd[0].js_blocks) {

  1135.             if (bd[1].js_blocks)

  1136.                 av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel pair!\n");

  1137. 

  1138.             for (s = 0; s < div_blocks[b]; s++)

  1139.                 bd[0].raw_samples[s] = bd[1].raw_samples[s] - bd[0].raw_samples[s];

  1140.         } else if (bd[1].js_blocks) {

  1141.             for (s = 0; s < div_blocks[b]; s++)

  1142.                 bd[1].raw_samples[s] = bd[1].raw_samples[s] + bd[0].raw_samples[s];

  1143.         }

  1144. 

  1145.         offset  += div_blocks[b];

  1146.         bd[0].ra_block = 0;

  1147.         bd[1].ra_block = 0;

  1148.     }

  1149. 

  1150.     // store carryover raw samples,

  1151.     // the others channel raw samples are stored by the calling function.

  1152.     memmove(ctx->raw_samples[c] - sconf->max_order,

  1153.             ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1154.             sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1155. 

  1156.     return 0;

  1157. }

  1158. 

  1159. 

  1160. /** Read the channel data.

  1161.   */

  1162. static int read_channel_data(ALSDecContext *ctx, ALSChannelData *cd, int c)

  1163. {

  1164.     GetBitContext *gb       = &ctx->gb;

  1165.     ALSChannelData *current = cd;

  1166.     unsigned int channels   = ctx->avctx->channels;

  1167.     int entries             = 0;

  1168. 

  1169.     while (entries < channels && !(current->stop_flag = get_bits1(gb))) {

  1170.         current->master_channel = get_bits_long(gb, av_ceil_log2(channels));

  1171. 

  1172.         if (current->master_channel >= channels) {

  1173.             av_log(ctx->avctx, AV_LOG_ERROR, "Invalid master channel!\n");

  1174.             return -1;

  1175.         }

  1176. 

  1177.         if (current->master_channel != c) {

  1178.             current->time_diff_flag = get_bits1(gb);

  1179.             current->weighting[0]   = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 32)];

  1180.             current->weighting[1]   = mcc_weightings[av_clip(decode_rice(gb, 2) + 14, 0, 32)];

  1181.             current->weighting[2]   = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 32)];

  1182. 

  1183.             if (current->time_diff_flag) {

  1184.                 current->weighting[3] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 32)];

  1185.                 current->weighting[4] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 32)];

  1186.                 current->weighting[5] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 32)];

  1187. 

  1188.                 current->time_diff_sign  = get_bits1(gb);

  1189.                 current->time_diff_index = get_bits(gb, ctx->ltp_lag_length - 3) + 3;

  1190.             }

  1191.         }

  1192. 

  1193.         current++;

  1194.         entries++;

  1195.     }

  1196. 

  1197.     if (entries == channels) {

  1198.         av_log(ctx->avctx, AV_LOG_ERROR, "Damaged channel data!\n");

  1199.         return -1;

  1200.     }

  1201. 

  1202.     align_get_bits(gb);

  1203.     return 0;

  1204. }

  1205. 

  1206. 

  1207. /** Recursively reverts the inter-channel correlation for a block.

  1208.  */

  1209. static int revert_channel_correlation(ALSDecContext *ctx, ALSBlockData *bd,

  1210.                                        ALSChannelData **cd, int *reverted,

  1211.                                        unsigned int offset, int c)

  1212. {

  1213.     ALSChannelData *ch = cd[c];

  1214.     unsigned int   dep = 0;

  1215.     unsigned int channels = ctx->avctx->channels;

  1216. 

  1217.     if (reverted[c])

  1218.         return 0;

  1219. 

  1220.     reverted[c] = 1;

  1221. 

  1222.     while (dep < channels && !ch[dep].stop_flag) {

  1223.         revert_channel_correlation(ctx, bd, cd, reverted, offset,

  1224.                                    ch[dep].master_channel);

  1225. 

  1226.         dep++;

  1227.     }

  1228. 

  1229.     if (dep == channels) {

  1230.         av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel correlation!\n");

  1231.         return -1;

  1232.     }

  1233. 

  1234.     bd->const_block = ctx->const_block + c;

  1235.     bd->shift_lsbs  = ctx->shift_lsbs + c;

  1236.     bd->opt_order   = ctx->opt_order + c;

  1237.     bd->store_prev_samples = ctx->store_prev_samples + c;

  1238.     bd->use_ltp     = ctx->use_ltp + c;

  1239.     bd->ltp_lag     = ctx->ltp_lag + c;

  1240.     bd->ltp_gain    = ctx->ltp_gain[c];

  1241.     bd->lpc_cof     = ctx->lpc_cof[c];

  1242.     bd->quant_cof   = ctx->quant_cof[c];

  1243.     bd->raw_samples = ctx->raw_samples[c] + offset;

  1244. 

  1245.     dep = 0;

  1246.     while (!ch[dep].stop_flag) {

  1247.         unsigned int smp;

  1248.         unsigned int begin = 1;

  1249.         unsigned int end   = bd->block_length - 1;

  1250.         int64_t y;

  1251.         int32_t *master = ctx->raw_samples[ch[dep].master_channel] + offset;

  1252. 

  1253.         if (ch[dep].time_diff_flag) {

  1254.             int t = ch[dep].time_diff_index;

  1255. 

  1256.             if (ch[dep].time_diff_sign) {

  1257.                 t      = -t;

  1258.                 begin -= t;

  1259.             } else {

  1260.                 end   -= t;

  1261.             }

  1262. 

  1263.             for (smp = begin; smp < end; smp++) {

  1264.                 y  = (1 << 6) +

  1265.                      MUL64(ch[dep].weighting[0], master[smp - 1    ]) +

  1266.                      MUL64(ch[dep].weighting[1], master[smp        ]) +

  1267.                      MUL64(ch[dep].weighting[2], master[smp + 1    ]) +

  1268.                      MUL64(ch[dep].weighting[3], master[smp - 1 + t]) +

  1269.                      MUL64(ch[dep].weighting[4], master[smp     + t]) +

  1270.                      MUL64(ch[dep].weighting[5], master[smp + 1 + t]);

  1271. 

  1272.                 bd->raw_samples[smp] += y >> 7;

  1273.             }

  1274.         } else {

  1275.             for (smp = begin; smp < end; smp++) {

  1276.                 y  = (1 << 6) +

  1277.                      MUL64(ch[dep].weighting[0], master[smp - 1]) +

  1278.                      MUL64(ch[dep].weighting[1], master[smp    ]) +

  1279.                      MUL64(ch[dep].weighting[2], master[smp + 1]);

  1280. 

  1281.                 bd->raw_samples[smp] += y >> 7;

  1282.             }

  1283.         }

  1284. 

  1285.         dep++;

  1286.     }

  1287. 

  1288.     return 0;

  1289. }

  1290. 

  1291. 

  1292. /** Read the frame data.

  1293.  */

  1294. static int read_frame_data(ALSDecContext *ctx, unsigned int ra_frame)

  1295. {

  1296.     ALSSpecificConfig *sconf = &ctx->sconf;

  1297.     AVCodecContext *avctx    = ctx->avctx;

  1298.     GetBitContext *gb = &ctx->gb;

  1299.     unsigned int div_blocks[32];                ///< block sizes.

  1300.     unsigned int c;

  1301.     unsigned int js_blocks[2];

  1302. 

  1303.     uint32_t bs_info = 0;

  1304. 

  1305.     // skip the size of the ra unit if present in the frame

  1306.     if (sconf->ra_flag == RA_FLAG_FRAMES && ra_frame)

  1307.         skip_bits_long(gb, 32);

  1308. 

  1309.     if (sconf->mc_coding && sconf->joint_stereo) {

  1310.         ctx->js_switch = get_bits1(gb);

  1311.         align_get_bits(gb);

  1312.     }

  1313. 

  1314.     if (!sconf->mc_coding || ctx->js_switch) {

  1315.         int independent_bs = !sconf->joint_stereo;

  1316. 

  1317.         for (c = 0; c < avctx->channels; c++) {

  1318.             js_blocks[0] = 0;

  1319.             js_blocks[1] = 0;

  1320. 

  1321.             get_block_sizes(ctx, div_blocks, &bs_info);

  1322. 

  1323.             // if joint_stereo and block_switching is set, independent decoding

  1324.             // is signaled via the first bit of bs_info

  1325.             if (sconf->joint_stereo && sconf->block_switching)

  1326.                 if (bs_info >> 31)

  1327.                     independent_bs = 2;

  1328. 

  1329.             // if this is the last channel, it has to be decoded independently

  1330.             if (c == avctx->channels - 1)

  1331.                 independent_bs = 1;

  1332. 

  1333.             if (independent_bs) {

  1334.                 if (decode_blocks_ind(ctx, ra_frame, c, div_blocks, js_blocks))

  1335.                     return -1;

  1336. 

  1337.                 independent_bs--;

  1338.             } else {

  1339.                 if (decode_blocks(ctx, ra_frame, c, div_blocks, js_blocks))

  1340.                     return -1;

  1341. 

  1342.                 c++;

  1343.             }

  1344. 

  1345.             // store carryover raw samples

  1346.             memmove(ctx->raw_samples[c] - sconf->max_order,

  1347.                     ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1348.                     sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1349.         }

  1350.     } else { // multi-channel coding

  1351.         ALSBlockData   bd = { 0 };

  1352.         int            b, ret;

  1353.         int            *reverted_channels = ctx->reverted_channels;

  1354.         unsigned int   offset             = 0;

  1355. 

  1356.         for (c = 0; c < avctx->channels; c++)

  1357.             if (ctx->chan_data[c] < ctx->chan_data_buffer) {

  1358.                 av_log(ctx->avctx, AV_LOG_ERROR, "Invalid channel data!\n");

  1359.                 return -1;

  1360.             }

  1361. 

  1362.         memset(reverted_channels, 0, sizeof(*reverted_channels) * avctx->channels);

  1363. 

  1364.         bd.ra_block         = ra_frame;

  1365.         bd.prev_raw_samples = ctx->prev_raw_samples;

  1366. 

  1367.         get_block_sizes(ctx, div_blocks, &bs_info);

  1368. 

  1369.         for (b = 0; b < ctx->num_blocks; b++) {

  1370.             bd.block_length = div_blocks[b];

  1371. 

  1372.             for (c = 0; c < avctx->channels; c++) {

  1373.                 bd.const_block = ctx->const_block + c;

  1374.                 bd.shift_lsbs  = ctx->shift_lsbs + c;

  1375.                 bd.opt_order   = ctx->opt_order + c;

  1376.                 bd.store_prev_samples = ctx->store_prev_samples + c;

  1377.                 bd.use_ltp     = ctx->use_ltp + c;

  1378.                 bd.ltp_lag     = ctx->ltp_lag + c;

  1379.                 bd.ltp_gain    = ctx->ltp_gain[c];

  1380.                 bd.lpc_cof     = ctx->lpc_cof[c];

  1381.                 bd.quant_cof   = ctx->quant_cof[c];

  1382.                 bd.raw_samples = ctx->raw_samples[c] + offset;

  1383.                 bd.raw_other   = NULL;

  1384. 

  1385.                 if ((ret = read_block(ctx, &bd)) < 0)

  1386.                     return ret;

  1387.                 if ((ret = read_channel_data(ctx, ctx->chan_data[c], c)) < 0)

  1388.                     return ret;

  1389.             }

  1390. 

  1391.             for (c = 0; c < avctx->channels; c++)

  1392.                 if (revert_channel_correlation(ctx, &bd, ctx->chan_data,

  1393.                                                reverted_channels, offset, c))

  1394.                     return -1;

  1395. 

  1396.             for (c = 0; c < avctx->channels; c++) {

  1397.                 bd.const_block = ctx->const_block + c;

  1398.                 bd.shift_lsbs  = ctx->shift_lsbs + c;

  1399.                 bd.opt_order   = ctx->opt_order + c;

  1400.                 bd.store_prev_samples = ctx->store_prev_samples + c;

  1401.                 bd.use_ltp     = ctx->use_ltp + c;

  1402.                 bd.ltp_lag     = ctx->ltp_lag + c;

  1403.                 bd.ltp_gain    = ctx->ltp_gain[c];

  1404.                 bd.lpc_cof     = ctx->lpc_cof[c];

  1405.                 bd.quant_cof   = ctx->quant_cof[c];

  1406.                 bd.raw_samples = ctx->raw_samples[c] + offset;

  1407.                 if ((ret = decode_block(ctx, &bd)) < 0)

  1408.                     return ret;

  1409.             }

  1410. 

  1411.             memset(reverted_channels, 0, avctx->channels * sizeof(*reverted_channels));

  1412.             offset      += div_blocks[b];

  1413.             bd.ra_block  = 0;

  1414.         }

  1415. 

  1416.         // store carryover raw samples

  1417.         for (c = 0; c < avctx->channels; c++)

  1418.             memmove(ctx->raw_samples[c] - sconf->max_order,

  1419.                     ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1420.                     sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1421.     }

  1422. 

  1423.     // TODO: read_diff_float_data

  1424. 

  1425.     return 0;

  1426. }

  1427. 

  1428. 

  1429. /** Decode an ALS frame.

  1430.  */

  1431. static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr,

  1432.                         AVPacket *avpkt)

  1433. {

  1434.     ALSDecContext *ctx       = avctx->priv_data;

  1435.     ALSSpecificConfig *sconf = &ctx->sconf;

  1436.     const uint8_t *buffer    = avpkt->data;

  1437.     int buffer_size          = avpkt->size;

  1438.     int invalid_frame, ret;

  1439.     unsigned int c, sample, ra_frame, bytes_read, shift;

  1440. 

  1441.     init_get_bits(&ctx->gb, buffer, buffer_size * 8);

  1442. 

  1443.     // In the case that the distance between random access frames is set to zero

  1444.     // (sconf->ra_distance == 0) no frame is treated as a random access frame.

  1445.     // For the first frame, if prediction is used, all samples used from the

  1446.     // previous frame are assumed to be zero.

  1447.     ra_frame = sconf->ra_distance && !(ctx->frame_id % sconf->ra_distance);

  1448. 

  1449.     // the last frame to decode might have a different length

  1450.     if (sconf->samples != 0xFFFFFFFF)

  1451.         ctx->cur_frame_length = FFMIN(sconf->samples - ctx->frame_id * (uint64_t) sconf->frame_length,

  1452.                                       sconf->frame_length);

  1453.     else

  1454.         ctx->cur_frame_length = sconf->frame_length;

  1455. 

  1456.     // decode the frame data

  1457.     if ((invalid_frame = read_frame_data(ctx, ra_frame)) < 0)

  1458.         av_log(ctx->avctx, AV_LOG_WARNING,

  1459.                "Reading frame data failed. Skipping RA unit.\n");

  1460. 

  1461.     ctx->frame_id++;

  1462. 

  1463.     /* get output buffer */

  1464.     ctx->frame.nb_samples = ctx->cur_frame_length;

  1465.     if ((ret = ff_get_buffer(avctx, &ctx->frame)) < 0) {

  1466.         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");

  1467.         return ret;

  1468.     }

  1469. 

  1470.     // transform decoded frame into output format

  1471.     #define INTERLEAVE_OUTPUT(bps)                                 \

  1472.     {                                                              \

  1473.         int##bps##_t *dest = (int##bps##_t*)ctx->frame.data[0];    \

  1474.         shift = bps - ctx->avctx->bits_per_raw_sample;             \

  1475.         for (sample = 0; sample < ctx->cur_frame_length; sample++) \

  1476.             for (c = 0; c < avctx->channels; c++)                  \

  1477.                 *dest++ = ctx->raw_samples[c][sample] << shift;    \

  1478.     }

  1479. 

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

  1481.         INTERLEAVE_OUTPUT(16)

  1482.     } else {

  1483.         INTERLEAVE_OUTPUT(32)

  1484.     }

  1485. 

  1486.     // update CRC

  1487.     if (sconf->crc_enabled && (avctx->err_recognition & AV_EF_CRCCHECK)) {

  1488.         int swap = HAVE_BIGENDIAN != sconf->msb_first;

  1489. 

  1490.         if (ctx->avctx->bits_per_raw_sample == 24) {

  1491.             int32_t *src = (int32_t *)ctx->frame.data[0];

  1492. 

  1493.             for (sample = 0;

  1494.                  sample < ctx->cur_frame_length * avctx->channels;

  1495.                  sample++) {

  1496.                 int32_t v;

  1497. 

  1498.                 if (swap)

  1499.                     v = av_bswap32(src[sample]);

  1500.                 else

  1501.                     v = src[sample];

  1502.                 if (!HAVE_BIGENDIAN)

  1503.                     v >>= 8;

  1504. 

  1505.                 ctx->crc = av_crc(ctx->crc_table, ctx->crc, (uint8_t*)(&v), 3);

  1506.             }

  1507.         } else {

  1508.             uint8_t *crc_source;

  1509. 

  1510.             if (swap) {

  1511.                 if (ctx->avctx->bits_per_raw_sample <= 16) {

  1512.                     int16_t *src  = (int16_t*) ctx->frame.data[0];

  1513.                     int16_t *dest = (int16_t*) ctx->crc_buffer;

  1514.                     for (sample = 0;

  1515.                          sample < ctx->cur_frame_length * avctx->channels;

  1516.                          sample++)

  1517.                         *dest++ = av_bswap16(src[sample]);

  1518.                 } else {

  1519.                     ctx->dsp.bswap_buf((uint32_t*)ctx->crc_buffer,

  1520.                                        (uint32_t *)ctx->frame.data[0],

  1521.                                        ctx->cur_frame_length * avctx->channels);

  1522.                 }

  1523.                 crc_source = ctx->crc_buffer;

  1524.             } else {

  1525.                 crc_source = ctx->frame.data[0];

  1526.             }

  1527. 

  1528.             ctx->crc = av_crc(ctx->crc_table, ctx->crc, crc_source,

  1529.                               ctx->cur_frame_length * avctx->channels *

  1530.                               av_get_bytes_per_sample(avctx->sample_fmt));

  1531.         }

  1532. 

  1533. 

  1534.         // check CRC sums if this is the last frame

  1535.         if (ctx->cur_frame_length != sconf->frame_length &&

  1536.             ctx->crc_org != ctx->crc) {

  1537.             av_log(avctx, AV_LOG_ERROR, "CRC error.\n");

  1538.         }

  1539.     }

  1540. 

  1541.     *got_frame_ptr   = 1;

  1542.     *(AVFrame *)data = ctx->frame;

  1543. 

  1544. 

  1545.     bytes_read = invalid_frame ? buffer_size :

  1546.                                  (get_bits_count(&ctx->gb) + 7) >> 3;

  1547. 

  1548.     return bytes_read;

  1549. }

  1550. 

  1551. 

  1552. /** Uninitialize the ALS decoder.

  1553.  */

  1554. static av_cold int decode_end(AVCodecContext *avctx)

  1555. {

  1556.     ALSDecContext *ctx = avctx->priv_data;

  1557. 

  1558.     av_freep(&ctx->sconf.chan_pos);

  1559. 

  1560.     ff_bgmc_end(&ctx->bgmc_lut, &ctx->bgmc_lut_status);

  1561. 

  1562.     av_freep(&ctx->const_block);

  1563.     av_freep(&ctx->shift_lsbs);

  1564.     av_freep(&ctx->opt_order);

  1565.     av_freep(&ctx->store_prev_samples);

  1566.     av_freep(&ctx->use_ltp);

  1567.     av_freep(&ctx->ltp_lag);

  1568.     av_freep(&ctx->ltp_gain);

  1569.     av_freep(&ctx->ltp_gain_buffer);

  1570.     av_freep(&ctx->quant_cof);

  1571.     av_freep(&ctx->lpc_cof);

  1572.     av_freep(&ctx->quant_cof_buffer);

  1573.     av_freep(&ctx->lpc_cof_buffer);

  1574.     av_freep(&ctx->lpc_cof_reversed_buffer);

  1575.     av_freep(&ctx->prev_raw_samples);

  1576.     av_freep(&ctx->raw_samples);

  1577.     av_freep(&ctx->raw_buffer);

  1578.     av_freep(&ctx->chan_data);

  1579.     av_freep(&ctx->chan_data_buffer);

  1580.     av_freep(&ctx->reverted_channels);

  1581.     av_freep(&ctx->crc_buffer);

  1582. 

  1583.     return 0;

  1584. }

  1585. 

  1586. 

  1587. /** Initialize the ALS decoder.

  1588.  */

  1589. static av_cold int decode_init(AVCodecContext *avctx)

  1590. {

  1591.     unsigned int c;

  1592.     unsigned int channel_size;

  1593.     int num_buffers;

  1594.     ALSDecContext *ctx = avctx->priv_data;

  1595.     ALSSpecificConfig *sconf = &ctx->sconf;

  1596.     ctx->avctx = avctx;

  1597. 

  1598.     if (!avctx->extradata) {

  1599.         av_log(avctx, AV_LOG_ERROR, "Missing required ALS extradata.\n");

  1600.         return -1;

  1601.     }

  1602. 

  1603.     if (read_specific_config(ctx)) {

  1604.         av_log(avctx, AV_LOG_ERROR, "Reading ALSSpecificConfig failed.\n");

  1605.         decode_end(avctx);

  1606.         return -1;

  1607.     }

  1608. 

  1609.     if (check_specific_config(ctx)) {

  1610.         decode_end(avctx);

  1611.         return -1;

  1612.     }

  1613. 

  1614.     if (sconf->bgmc)

  1615.         ff_bgmc_init(avctx, &ctx->bgmc_lut, &ctx->bgmc_lut_status);

  1616. 

  1617.     if (sconf->floating) {

  1618.         avctx->sample_fmt          = AV_SAMPLE_FMT_FLT;

  1619.         avctx->bits_per_raw_sample = 32;

  1620.     } else {

  1621.         avctx->sample_fmt          = sconf->resolution > 1

  1622.                                      ? AV_SAMPLE_FMT_S32 : AV_SAMPLE_FMT_S16;

  1623.         avctx->bits_per_raw_sample = (sconf->resolution + 1) * 8;

  1624.     }

  1625. 

  1626.     // set maximum Rice parameter for progressive decoding based on resolution

  1627.     // This is not specified in 14496-3 but actually done by the reference

  1628.     // codec RM22 revision 2.

  1629.     ctx->s_max = sconf->resolution > 1 ? 31 : 15;

  1630. 

  1631.     // set lag value for long-term prediction

  1632.     ctx->ltp_lag_length = 8 + (avctx->sample_rate >=  96000) +

  1633.                               (avctx->sample_rate >= 192000);

  1634. 

  1635.     // allocate quantized parcor coefficient buffer

  1636.     num_buffers = sconf->mc_coding ? avctx->channels : 1;

  1637. 

  1638.     ctx->quant_cof        = av_malloc(sizeof(*ctx->quant_cof) * num_buffers);

  1639.     ctx->lpc_cof          = av_malloc(sizeof(*ctx->lpc_cof)   * num_buffers);

  1640.     ctx->quant_cof_buffer = av_malloc(sizeof(*ctx->quant_cof_buffer) *

  1641.                                       num_buffers * sconf->max_order);

  1642.     ctx->lpc_cof_buffer   = av_malloc(sizeof(*ctx->lpc_cof_buffer) *

  1643.                                       num_buffers * sconf->max_order);

  1644.     ctx->lpc_cof_reversed_buffer = av_malloc(sizeof(*ctx->lpc_cof_buffer) *

  1645.                                              sconf->max_order);

  1646. 

  1647.     if (!ctx->quant_cof              || !ctx->lpc_cof        ||

  1648.         !ctx->quant_cof_buffer       || !ctx->lpc_cof_buffer ||

  1649.         !ctx->lpc_cof_reversed_buffer) {

  1650.         av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1651.         return AVERROR(ENOMEM);

  1652.     }

  1653. 

  1654.     // assign quantized parcor coefficient buffers

  1655.     for (c = 0; c < num_buffers; c++) {

  1656.         ctx->quant_cof[c] = ctx->quant_cof_buffer + c * sconf->max_order;

  1657.         ctx->lpc_cof[c]   = ctx->lpc_cof_buffer   + c * sconf->max_order;

  1658.     }

  1659. 

  1660.     // allocate and assign lag and gain data buffer for ltp mode

  1661.     ctx->const_block     = av_malloc (sizeof(*ctx->const_block) * num_buffers);

  1662.     ctx->shift_lsbs      = av_malloc (sizeof(*ctx->shift_lsbs)  * num_buffers);

  1663.     ctx->opt_order       = av_malloc (sizeof(*ctx->opt_order)   * num_buffers);

  1664.     ctx->store_prev_samples = av_malloc(sizeof(*ctx->store_prev_samples) * num_buffers);

  1665.     ctx->use_ltp         = av_mallocz(sizeof(*ctx->use_ltp)  * num_buffers);

  1666.     ctx->ltp_lag         = av_malloc (sizeof(*ctx->ltp_lag)  * num_buffers);

  1667.     ctx->ltp_gain        = av_malloc (sizeof(*ctx->ltp_gain) * num_buffers);

  1668.     ctx->ltp_gain_buffer = av_malloc (sizeof(*ctx->ltp_gain_buffer) *

  1669.                                       num_buffers * 5);

  1670. 

  1671.     if (!ctx->const_block || !ctx->shift_lsbs ||

  1672.         !ctx->opt_order || !ctx->store_prev_samples ||

  1673.         !ctx->use_ltp  || !ctx->ltp_lag ||

  1674.         !ctx->ltp_gain || !ctx->ltp_gain_buffer) {

  1675.         av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1676.         decode_end(avctx);

  1677.         return AVERROR(ENOMEM);

  1678.     }

  1679. 

  1680.     for (c = 0; c < num_buffers; c++)

  1681.         ctx->ltp_gain[c] = ctx->ltp_gain_buffer + c * 5;

  1682. 

  1683.     // allocate and assign channel data buffer for mcc mode

  1684.     if (sconf->mc_coding) {

  1685.         ctx->chan_data_buffer  = av_malloc(sizeof(*ctx->chan_data_buffer) *

  1686.                                            num_buffers * num_buffers);

  1687.         ctx->chan_data         = av_malloc(sizeof(*ctx->chan_data) *

  1688.                                            num_buffers);

  1689.         ctx->reverted_channels = av_malloc(sizeof(*ctx->reverted_channels) *

  1690.                                            num_buffers);

  1691. 

  1692.         if (!ctx->chan_data_buffer || !ctx->chan_data || !ctx->reverted_channels) {

  1693.             av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1694.             decode_end(avctx);

  1695.             return AVERROR(ENOMEM);

  1696.         }

  1697. 

  1698.         for (c = 0; c < num_buffers; c++)

  1699.             ctx->chan_data[c] = ctx->chan_data_buffer + c * num_buffers;

  1700.     } else {

  1701.         ctx->chan_data         = NULL;

  1702.         ctx->chan_data_buffer  = NULL;

  1703.         ctx->reverted_channels = NULL;

  1704.     }

  1705. 

  1706.     channel_size      = sconf->frame_length + sconf->max_order;

  1707. 

  1708.     ctx->prev_raw_samples = av_malloc (sizeof(*ctx->prev_raw_samples) * sconf->max_order);

  1709.     ctx->raw_buffer       = av_mallocz(sizeof(*ctx->     raw_buffer)  * avctx->channels * channel_size);

  1710.     ctx->raw_samples      = av_malloc (sizeof(*ctx->     raw_samples) * avctx->channels);

  1711. 

  1712.     // allocate previous raw sample buffer

  1713.     if (!ctx->prev_raw_samples || !ctx->raw_buffer|| !ctx->raw_samples) {

  1714.         av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1715.         decode_end(avctx);

  1716.         return AVERROR(ENOMEM);

  1717.     }

  1718. 

  1719.     // assign raw samples buffers

  1720.     ctx->raw_samples[0] = ctx->raw_buffer + sconf->max_order;

  1721.     for (c = 1; c < avctx->channels; c++)

  1722.         ctx->raw_samples[c] = ctx->raw_samples[c - 1] + channel_size;

  1723. 

  1724.     // allocate crc buffer

  1725.     if (HAVE_BIGENDIAN != sconf->msb_first && sconf->crc_enabled &&

  1726.         (avctx->err_recognition & AV_EF_CRCCHECK)) {

  1727.         ctx->crc_buffer = av_malloc(sizeof(*ctx->crc_buffer) *

  1728.                                     ctx->cur_frame_length *

  1729.                                     avctx->channels *

  1730.                                     av_get_bytes_per_sample(avctx->sample_fmt));

  1731.         if (!ctx->crc_buffer) {

  1732.             av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1733.             decode_end(avctx);

  1734.             return AVERROR(ENOMEM);

  1735.         }

  1736.     }

  1737. 

  1738.     ff_dsputil_init(&ctx->dsp, avctx);

  1739. 

  1740.     avcodec_get_frame_defaults(&ctx->frame);

  1741.     avctx->coded_frame = &ctx->frame;

  1742. 

  1743.     return 0;

  1744. }

  1745. 

  1746. 

  1747. /** Flush (reset) the frame ID after seeking.

  1748.  */

  1749. static av_cold void flush(AVCodecContext *avctx)

  1750. {

  1751.     ALSDecContext *ctx = avctx->priv_data;

  1752. 

  1753.     ctx->frame_id = 0;

  1754. }

  1755. 

  1756. 

  1757. AVCodec ff_als_decoder = {

  1758.     .name           = "als",

  1759.     .type           = AVMEDIA_TYPE_AUDIO,

  1760.     .id             = AV_CODEC_ID_MP4ALS,

  1761.     .priv_data_size = sizeof(ALSDecContext),

  1762.     .init           = decode_init,

  1763.     .close          = decode_end,

  1764.     .decode         = decode_frame,

  1765.     .flush          = flush,

  1766.     .capabilities   = CODEC_CAP_SUBFRAMES | CODEC_CAP_DR1,

  1767.     .long_name      = NULL_IF_CONFIG_SMALL("MPEG-4 Audio Lossless Coding (ALS)"),

  1768. };