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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. #include "avcodec.h"

  29. #include "get_bits.h"

  30. #include "unary.h"

  31. #include "mpeg4audio.h"

  32. #include "bytestream.h"

  33. #include "bgmc.h"

  34. #include "dsputil.h"

  35. #include "internal.h"

  36. #include "libavutil/samplefmt.h"

  37. #include "libavutil/crc.h"

  38. 

  39. #include <stdint.h>

  40. 

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

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

  43.  *  by the encoder and stored in ALSSpecificConfig.

  44.  */

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

  46.     { {-52, 4}, {-29, 5}, {-31, 4}, { 19, 4}, {-16, 4},

  47.       { 12, 3}, { -7, 3}, {  9, 3}, { -5, 3}, {  6, 3},

  48.       { -4, 3}, {  3, 3}, { -3, 2}, {  3, 2}, { -2, 2},

  49.       {  3, 2}, { -1, 2}, {  2, 2}, { -1, 2}, {  2, 2} },

  50.     { {-58, 3}, {-42, 4}, {-46, 4}, { 37, 5}, {-36, 4},

  51.       { 29, 4}, {-29, 4}, { 25, 4}, {-23, 4}, { 20, 4},

  52.       {-17, 4}, { 16, 4}, {-12, 4}, { 12, 3}, {-10, 4},

  53.       {  7, 3}, { -4, 4}, {  3, 3}, { -1, 3}, {  1, 3} },

  54.     { {-59, 3}, {-45, 5}, {-50, 4}, { 38, 4}, {-39, 4},

  55.       { 32, 4}, {-30, 4}, { 25, 3}, {-23, 3}, { 20, 3},

  56.       {-20, 3}, { 16, 3}, {-13, 3}, { 10, 3}, { -7, 3},

  57.       {  3, 3}, {  0, 3}, { -1, 3}, {  2, 3}, { -1, 2} }

  58. };

  59. 

  60. 

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

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

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

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

  65.  */

  66. static const int16_t parcor_scaled_values[] = {

  67.     -1048544 / 32, -1048288 / 32, -1047776 / 32, -1047008 / 32,

  68.     -1045984 / 32, -1044704 / 32, -1043168 / 32, -1041376 / 32,

  69.     -1039328 / 32, -1037024 / 32, -1034464 / 32, -1031648 / 32,

  70.     -1028576 / 32, -1025248 / 32, -1021664 / 32, -1017824 / 32,

  71.     -1013728 / 32, -1009376 / 32, -1004768 / 32,  -999904 / 32,

  72.      -994784 / 32,  -989408 / 32,  -983776 / 32,  -977888 / 32,

  73.      -971744 / 32,  -965344 / 32,  -958688 / 32,  -951776 / 32,

  74.      -944608 / 32,  -937184 / 32,  -929504 / 32,  -921568 / 32,

  75.      -913376 / 32,  -904928 / 32,  -896224 / 32,  -887264 / 32,

  76.      -878048 / 32,  -868576 / 32,  -858848 / 32,  -848864 / 32,

  77.      -838624 / 32,  -828128 / 32,  -817376 / 32,  -806368 / 32,

  78.      -795104 / 32,  -783584 / 32,  -771808 / 32,  -759776 / 32,

  79.      -747488 / 32,  -734944 / 32,  -722144 / 32,  -709088 / 32,

  80.      -695776 / 32,  -682208 / 32,  -668384 / 32,  -654304 / 32,

  81.      -639968 / 32,  -625376 / 32,  -610528 / 32,  -595424 / 32,

  82.      -580064 / 32,  -564448 / 32,  -548576 / 32,  -532448 / 32,

  83.      -516064 / 32,  -499424 / 32,  -482528 / 32,  -465376 / 32,

  84.      -447968 / 32,  -430304 / 32,  -412384 / 32,  -394208 / 32,

  85.      -375776 / 32,  -357088 / 32,  -338144 / 32,  -318944 / 32,

  86.      -299488 / 32,  -279776 / 32,  -259808 / 32,  -239584 / 32,

  87.      -219104 / 32,  -198368 / 32,  -177376 / 32,  -156128 / 32,

  88.      -134624 / 32,  -112864 / 32,   -90848 / 32,   -68576 / 32,

  89.       -46048 / 32,   -23264 / 32,     -224 / 32,    23072 / 32,

  90.        46624 / 32,    70432 / 32,    94496 / 32,   118816 / 32,

  91.       143392 / 32,   168224 / 32,   193312 / 32,   218656 / 32,

  92.       244256 / 32,   270112 / 32,   296224 / 32,   322592 / 32,

  93.       349216 / 32,   376096 / 32,   403232 / 32,   430624 / 32,

  94.       458272 / 32,   486176 / 32,   514336 / 32,   542752 / 32,

  95.       571424 / 32,   600352 / 32,   629536 / 32,   658976 / 32,

  96.       688672 / 32,   718624 / 32,   748832 / 32,   779296 / 32,

  97.       810016 / 32,   840992 / 32,   872224 / 32,   903712 / 32,

  98.       935456 / 32,   967456 / 32,   999712 / 32,  1032224 / 32

  99. };

  100. 

  101. 

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

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

  104.  */

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

  106.     { 0,  8, 16,  24},

  107.     {32, 40, 48,  56},

  108.     {64, 70, 76,  82},

  109.     {88, 92, 96, 100}

  110. };

  111. 

  112. 

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

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

  115.  */

  116. static const int16_t mcc_weightings[] = {

  117.     204,  192,  179,  166,  153,  140,  128,  115,

  118.     102,   89,   76,   64,   51,   38,   25,   12,

  119.       0,  -12,  -25,  -38,  -51,  -64,  -76,  -89,

  120.    -102, -115, -128, -140, -153, -166, -179, -192

  121. };

  122. 

  123. 

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

  125.  */

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

  127.     { 74, 44, 25, 13,  7, 3},

  128.     { 68, 42, 24, 13,  7, 3},

  129.     { 58, 39, 23, 13,  7, 3},

  130.     {126, 70, 37, 19, 10, 5},

  131.     {132, 70, 37, 20, 10, 5},

  132.     {124, 70, 38, 20, 10, 5},

  133.     {120, 69, 37, 20, 11, 5},

  134.     {116, 67, 37, 20, 11, 5},

  135.     {108, 66, 36, 20, 10, 5},

  136.     {102, 62, 36, 20, 10, 5},

  137.     { 88, 58, 34, 19, 10, 5},

  138.     {162, 89, 49, 25, 13, 7},

  139.     {156, 87, 49, 26, 14, 7},

  140.     {150, 86, 47, 26, 14, 7},

  141.     {142, 84, 47, 26, 14, 7},

  142.     {131, 79, 46, 26, 14, 7}

  143. };

  144. 

  145. 

  146. enum RA_Flag {

  147.     RA_FLAG_NONE,

  148.     RA_FLAG_FRAMES,

  149.     RA_FLAG_HEADER

  150. };

  151. 

  152. 

  153. typedef struct {

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  176. } ALSSpecificConfig;

  177. 

  178. 

  179. typedef struct {

  180.     int stop_flag;

  181.     int master_channel;

  182.     int time_diff_flag;

  183.     int time_diff_sign;

  184.     int time_diff_index;

  185.     int weighting[6];

  186. } ALSChannelData;

  187. 

  188. 

  189. typedef struct {

  190.     AVCodecContext *avctx;

  191.     ALSSpecificConfig sconf;

  192.     GetBitContext gb;

  193.     DSPContext dsp;

  194.     const AVCRC *crc_table;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  225. } ALSDecContext;

  226. 

  227. 

  228. typedef struct {

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

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

  231.     int          *const_block;      ///< if true, this is a constant value 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.     av_dlog(avctx, "resolution = %i\n",           sconf->resolution);

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  270.     av_dlog(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 = avpriv_mpeg4audio_get_config(&m4ac, avctx->extradata,

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

  291. 

  292.     if (config_offset < 0)

  293.         return AVERROR_INVALIDDATA;

  294. 

  295.     skip_bits_long(&gb, config_offset);

  296. 

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

  298.         return AVERROR_INVALIDDATA;

  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 AVERROR_INVALIDDATA;

  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 AVERROR_INVALIDDATA;

  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 AVERROR_INVALIDDATA;

  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 AVERROR_INVALIDDATA;

  381. 

  382.     if (ht_size > INT32_MAX)

  383.         return AVERROR_PATCHWELCOME;

  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 AVERROR_INVALIDDATA;

  392. 

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

  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.             avpriv_report_missing_feature(ctx->avctx,   \

  422.                                           str);         \

  423.             error = errval;                             \

  424.         }                                               \

  425.     }

  426. 

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

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

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

  430. 

  431.     return error;

  432. }

  433. 

  434. 

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

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

  437.  */

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

  439.                           unsigned int div, unsigned int **div_blocks,

  440.                           unsigned int *num_blocks)

  441. {

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

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

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

  445.         n   *= 2;

  446.         div += 1;

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

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

  449.     } else {

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

  451.         // (bit implicitly not set)

  452.         **div_blocks = div;

  453.         (*div_blocks)++;

  454.         (*num_blocks)++;

  455.     }

  456. }

  457. 

  458. 

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

  460.  */

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

  462. {

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

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

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

  466. 

  467.     if (k > 1) {

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

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

  470.     } else if (!k) {

  471.         q >>= 1;

  472.     }

  473.     return r ? q : ~q;

  474. }

  475. 

  476. 

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

  478.  */

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

  480. {

  481.     int i, j;

  482. 

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

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

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

  486.         cof[i]  += tmp1;

  487.     }

  488.     if (i == j)

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

  490. 

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

  492. }

  493. 

  494. 

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

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

  497.  *  actual number of samples.

  498.  */

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

  500.                             uint32_t *bs_info)

  501. {

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

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

  504.     unsigned int *ptr_div_blocks = div_blocks;

  505.     unsigned int b;

  506. 

  507.     if (sconf->block_switching) {

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

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

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

  511.     }

  512. 

  513.     ctx->num_blocks = 0;

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

  515. 

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

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

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

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

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

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

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

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

  524.     // codec RM22 revision 2.

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

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

  527.     // of 14496-3.

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

  529.     // frame.

  530. 

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

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

  533. 

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

  535.         unsigned int remaining = ctx->cur_frame_length;

  536. 

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

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

  539.                 div_blocks[b] = remaining;

  540.                 ctx->num_blocks = b + 1;

  541.                 break;

  542.             }

  543. 

  544.             remaining -= div_blocks[b];

  545.         }

  546.     }

  547. }

  548. 

  549. 

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

  551.  */

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

  553. {

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

  555.     AVCodecContext *avctx    = ctx->avctx;

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

  557. 

  558.     *bd->raw_samples = 0;

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

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

  561. 

  562.     // skip 5 reserved bits

  563.     skip_bits(gb, 5);

  564. 

  565.     if (*bd->const_block) {

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

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

  568.     }

  569. 

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

  571.     *bd->const_block = 1;

  572. }

  573. 

  574. 

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

  576.  */

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

  578. {

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

  580.     int32_t  val = *bd->raw_samples;

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

  582. 

  583.     // write raw samples into buffer

  584.     for (; smp; smp--)

  585.         *dst++ = val;

  586. }

  587. 

  588. 

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

  590.  */

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

  592. {

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

  594.     AVCodecContext *avctx    = ctx->avctx;

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

  596.     unsigned int k;

  597.     unsigned int s[8];

  598.     unsigned int sx[8];

  599.     unsigned int sub_blocks, log2_sub_blocks, sb_length;

  600.     unsigned int start      = 0;

  601.     unsigned int opt_order;

  602.     int          sb;

  603.     int32_t      *quant_cof = bd->quant_cof;

  604.     int32_t      *current_res;

  605. 

  606. 

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

  608.     *bd->const_block = 0;

  609. 

  610.     *bd->opt_order  = 1;

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

  612. 

  613.     opt_order       = *bd->opt_order;

  614. 

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

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

  617.         log2_sub_blocks = 0;

  618.     } else {

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

  620.             log2_sub_blocks = get_bits(gb, 2);

  621.         else

  622.             log2_sub_blocks = 2 * get_bits1(gb);

  623.     }

  624. 

  625.     sub_blocks = 1 << log2_sub_blocks;

  626. 

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

  628.     // block_length must be evenly divisible by sub_blocks

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

  630.         av_log(avctx, AV_LOG_WARNING,

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

  632.         return AVERROR_INVALIDDATA;

  633.     }

  634. 

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

  636. 

  637.     if (sconf->bgmc) {

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

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

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

  641. 

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

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

  644.             s [k] >>= 4;

  645.         }

  646.     } else {

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

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

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

  650.     }

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

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

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

  654.             return AVERROR_INVALIDDATA;

  655.         }

  656. 

  657.     if (get_bits1(gb))

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

  659. 

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

  661. 

  662. 

  663.     if (!sconf->rlslms) {

  664.         if (sconf->adapt_order) {

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

  666.                                                 2, sconf->max_order + 1));

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

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

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

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

  671.                 return AVERROR_INVALIDDATA;

  672.             }

  673.         } else {

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

  675.         }

  676. 

  677.         opt_order = *bd->opt_order;

  678. 

  679.         if (opt_order) {

  680.             int add_base;

  681. 

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

  683.                 add_base = 0x7F;

  684. 

  685.                 // read coefficient 0

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

  687. 

  688.                 // read coefficient 1

  689.                 if (opt_order > 1)

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

  691. 

  692.                 // read coefficients 2 to opt_order

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

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

  695.             } else {

  696.                 int k_max;

  697.                 add_base = 1;

  698. 

  699.                 // read coefficient 0 to 19

  700.                 k_max = FFMIN(opt_order, 20);

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

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

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

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

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

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

  707.                         return AVERROR_INVALIDDATA;

  708.                     }

  709.                 }

  710. 

  711.                 // read coefficients 20 to 126

  712.                 k_max = FFMIN(opt_order, 127);

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

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

  715. 

  716.                 // read coefficients 127 to opt_order

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

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

  719. 

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

  721. 

  722.                 if (opt_order > 1)

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

  724.             }

  725. 

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

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

  728.         }

  729.     }

  730. 

  731.     // read LTP gain and lag values

  732.     if (sconf->long_term_prediction) {

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

  734. 

  735.         if (*bd->use_ltp) {

  736.             int r, c;

  737. 

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

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

  740. 

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

  742.             c                 = get_bits(gb, 2);

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

  744. 

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

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

  747. 

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

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

  750.         }

  751.     }

  752. 

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

  754.     if (bd->ra_block) {

  755.         if (opt_order)

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

  757.         if (opt_order > 1)

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

  759.         if (opt_order > 2)

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

  761. 

  762.         start = FFMIN(opt_order, 3);

  763.     }

  764. 

  765.     // read all residuals

  766.     if (sconf->bgmc) {

  767.         int          delta[8];

  768.         unsigned int k    [8];

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

  770. 

  771.         // read most significant bits

  772.         unsigned int high;

  773.         unsigned int low;

  774.         unsigned int value;

  775. 

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

  777. 

  778.         current_res = bd->raw_samples + start;

  779. 

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

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

  782. 

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

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

  785. 

  786.             ff_bgmc_decode(gb, sb_len, current_res,

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

  788. 

  789.             current_res += sb_len;

  790.         }

  791. 

  792.         ff_bgmc_decode_end(gb);

  793. 

  794. 

  795.         // read least significant bits and tails

  796.         current_res = bd->raw_samples + start;

  797. 

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

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

  800.             unsigned int cur_k         = k[sb];

  801.             unsigned int cur_s         = s[sb];

  802. 

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

  804.                 int32_t res = *current_res;

  805. 

  806.                 if (res == cur_tail_code) {

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

  808.                                           << (5 - delta[sb]);

  809. 

  810.                     res = decode_rice(gb, cur_s);

  811. 

  812.                     if (res >= 0) {

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

  814.                     } else {

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

  816.                     }

  817.                 } else {

  818.                     if (res > cur_tail_code)

  819.                         res--;

  820. 

  821.                     if (res & 1)

  822.                         res = -res;

  823. 

  824.                     res >>= 1;

  825. 

  826.                     if (cur_k) {

  827.                         res <<= cur_k;

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

  829.                     }

  830.                 }

  831. 

  832.                 *current_res++ = res;

  833.             }

  834.         }

  835.     } else {

  836.         current_res = bd->raw_samples + start;

  837. 

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

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

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

  841.      }

  842. 

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

  844.         align_get_bits(gb);

  845. 

  846.     return 0;

  847. }

  848. 

  849. 

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

  851.  */

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

  853. {

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

  855.     unsigned int block_length = bd->block_length;

  856.     unsigned int smp = 0;

  857.     unsigned int k;

  858.     int opt_order             = *bd->opt_order;

  859.     int sb;

  860.     int64_t y;

  861.     int32_t *quant_cof        = bd->quant_cof;

  862.     int32_t *lpc_cof          = bd->lpc_cof;

  863.     int32_t *raw_samples      = bd->raw_samples;

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

  865.     int32_t *lpc_cof_reversed = ctx->lpc_cof_reversed_buffer;

  866. 

  867.     // reverse long-term prediction

  868.     if (*bd->use_ltp) {

  869.         int ltp_smp;

  870. 

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

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

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

  874.             int end    = center + 3;

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

  876.             int base;

  877. 

  878.             y = 1 << 6;

  879. 

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

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

  882. 

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

  884.         }

  885.     }

  886. 

  887.     // reconstruct all samples from residuals

  888.     if (bd->ra_block) {

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

  890.             y = 1 << 19;

  891. 

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

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

  894. 

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

  896.             parcor_to_lpc(smp, quant_cof, lpc_cof);

  897.         }

  898.     } else {

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

  900.             parcor_to_lpc(k, quant_cof, lpc_cof);

  901. 

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

  903.         if (*bd->store_prev_samples)

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

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

  906. 

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

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

  909.             int32_t *left, *right;

  910. 

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

  912.                 left  = raw_samples;

  913.                 right = bd->raw_other;

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

  915.                 left  = bd->raw_other;

  916.                 right = raw_samples;

  917.             }

  918. 

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

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

  921.         }

  922. 

  923.         // reconstruct shifted signal

  924.         if (*bd->shift_lsbs)

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

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

  927.     }

  928. 

  929.     // reverse linear prediction coefficients for efficiency

  930.     lpc_cof = lpc_cof + opt_order;

  931. 

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

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

  934. 

  935.     // reconstruct raw samples

  936.     raw_samples = bd->raw_samples + smp;

  937.     lpc_cof     = lpc_cof_reversed + opt_order;

  938. 

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

  940.         y = 1 << 19;

  941. 

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

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

  944. 

  945.         *raw_samples -= y >> 20;

  946.     }

  947. 

  948.     raw_samples = bd->raw_samples;

  949. 

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

  951.     if (*bd->store_prev_samples)

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

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

  954. 

  955.     return 0;

  956. }

  957. 

  958. 

  959. /** Read the block data.

  960.  */

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

  962. {

  963.     int ret = 0;

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

  965. 

  966.     *bd->shift_lsbs = 0;

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

  968.     if (get_bits1(gb)) {

  969.         ret = read_var_block_data(ctx, bd);

  970.     } else {

  971.         read_const_block_data(ctx, bd);

  972.     }

  973. 

  974.     return ret;

  975. }

  976. 

  977. 

  978. /** Decode the block data.

  979.  */

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

  981. {

  982.     unsigned int smp;

  983.     int ret = 0;

  984. 

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

  986.     if (*bd->const_block)

  987.         decode_const_block_data(ctx, bd);

  988.     else

  989.         ret = decode_var_block_data(ctx, bd); // always return 0

  990. 

  991.     if (ret < 0)

  992.         return ret;

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

  1011.         return ret;

  1012. 

  1013.     return decode_block(ctx, bd);

  1014. }

  1015. 

  1016. 

  1017. /** Compute the number of samples left to decode for the current frame and

  1018.  *  sets these samples to zero.

  1019.  */

  1020. static void zero_remaining(unsigned int b, unsigned int b_max,

  1021.                            const unsigned int *div_blocks, int32_t *buf)

  1022. {

  1023.     unsigned int count = 0;

  1024. 

  1025.     for (; b < b_max; b++)

  1026.         count += div_blocks[b];

  1027. 

  1028.     if (count)

  1029.         memset(buf, 0, sizeof(*buf) * count);

  1030. }

  1031. 

  1032. 

  1033. /** Decode blocks independently.

  1034.  */

  1035. static int decode_blocks_ind(ALSDecContext *ctx, unsigned int ra_frame,

  1036.                              unsigned int c, const unsigned int *div_blocks,

  1037.                              unsigned int *js_blocks)

  1038. {

  1039.     int ret;

  1040.     unsigned int b;

  1041.     ALSBlockData bd = { 0 };

  1042. 

  1043.     bd.ra_block         = ra_frame;

  1044.     bd.const_block      = ctx->const_block;

  1045.     bd.shift_lsbs       = ctx->shift_lsbs;

  1046.     bd.opt_order        = ctx->opt_order;

  1047.     bd.store_prev_samples = ctx->store_prev_samples;

  1048.     bd.use_ltp          = ctx->use_ltp;

  1049.     bd.ltp_lag          = ctx->ltp_lag;

  1050.     bd.ltp_gain         = ctx->ltp_gain[0];

  1051.     bd.quant_cof        = ctx->quant_cof[0];

  1052.     bd.lpc_cof          = ctx->lpc_cof[0];

  1053.     bd.prev_raw_samples = ctx->prev_raw_samples;

  1054.     bd.raw_samples      = ctx->raw_samples[c];

  1055. 

  1056. 

  1057.     for (b = 0; b < ctx->num_blocks; b++) {

  1058.         bd.block_length     = div_blocks[b];

  1059. 

  1060.         if ((ret = read_decode_block(ctx, &bd)) < 0) {

  1061.             // damaged block, write zero for the rest of the frame

  1062.             zero_remaining(b, ctx->num_blocks, div_blocks, bd.raw_samples);

  1063.             return ret;

  1064.         }

  1065.         bd.raw_samples += div_blocks[b];

  1066.         bd.ra_block     = 0;

  1067.     }

  1068. 

  1069.     return 0;

  1070. }

  1071. 

  1072. 

  1073. /** Decode blocks dependently.

  1074.  */

  1075. static int decode_blocks(ALSDecContext *ctx, unsigned int ra_frame,

  1076.                          unsigned int c, const unsigned int *div_blocks,

  1077.                          unsigned int *js_blocks)

  1078. {

  1079.     ALSSpecificConfig *sconf = &ctx->sconf;

  1080.     unsigned int offset = 0;

  1081.     unsigned int b;

  1082.     int ret;

  1083.     ALSBlockData bd[2] = { { 0 } };

  1084. 

  1085.     bd[0].ra_block         = ra_frame;

  1086.     bd[0].const_block      = ctx->const_block;

  1087.     bd[0].shift_lsbs       = ctx->shift_lsbs;

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

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

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

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

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

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

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

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

  1096.     bd[0].js_blocks        = *js_blocks;

  1097. 

  1098.     bd[1].ra_block         = ra_frame;

  1099.     bd[1].const_block      = ctx->const_block;

  1100.     bd[1].shift_lsbs       = ctx->shift_lsbs;

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

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

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

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

  1105.     bd[1].ltp_gain         = ctx->ltp_gain[0];

  1106.     bd[1].quant_cof        = ctx->quant_cof[0];

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

  1108.     bd[1].prev_raw_samples = ctx->prev_raw_samples;

  1109.     bd[1].js_blocks        = *(js_blocks + 1);

  1110. 

  1111.     // decode all blocks

  1112.     for (b = 0; b < ctx->num_blocks; b++) {

  1113.         unsigned int s;

  1114. 

  1115.         bd[0].block_length = div_blocks[b];

  1116.         bd[1].block_length = div_blocks[b];

  1117. 

  1118.         bd[0].raw_samples  = ctx->raw_samples[c    ] + offset;

  1119.         bd[1].raw_samples  = ctx->raw_samples[c + 1] + offset;

  1120. 

  1121.         bd[0].raw_other    = bd[1].raw_samples;

  1122.         bd[1].raw_other    = bd[0].raw_samples;

  1123. 

  1124.         if ((ret = read_decode_block(ctx, &bd[0])) < 0 ||

  1125.             (ret = read_decode_block(ctx, &bd[1])) < 0)

  1126.             goto fail;

  1127. 

  1128.         // reconstruct joint-stereo blocks

  1129.         if (bd[0].js_blocks) {

  1130.             if (bd[1].js_blocks)

  1131.                 av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel pair!\n");

  1132. 

  1133.             for (s = 0; s < div_blocks[b]; s++)

  1134.                 bd[0].raw_samples[s] = bd[1].raw_samples[s] - bd[0].raw_samples[s];

  1135.         } else if (bd[1].js_blocks) {

  1136.             for (s = 0; s < div_blocks[b]; s++)

  1137.                 bd[1].raw_samples[s] = bd[1].raw_samples[s] + bd[0].raw_samples[s];

  1138.         }

  1139. 

  1140.         offset  += div_blocks[b];

  1141.         bd[0].ra_block = 0;

  1142.         bd[1].ra_block = 0;

  1143.     }

  1144. 

  1145.     // store carryover raw samples,

  1146.     // the others channel raw samples are stored by the calling function.

  1147.     memmove(ctx->raw_samples[c] - sconf->max_order,

  1148.             ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1149.             sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1150. 

  1151.     return 0;

  1152. fail:

  1153.     // damaged block, write zero for the rest of the frame

  1154.     zero_remaining(b, ctx->num_blocks, div_blocks, bd[0].raw_samples);

  1155.     zero_remaining(b, ctx->num_blocks, div_blocks, bd[1].raw_samples);

  1156.     return ret;

  1157. }

  1158. 

  1159. static inline int als_weighting(GetBitContext *gb, int k, int off)

  1160. {

  1161.     int idx = av_clip(decode_rice(gb, k) + off,

  1162.                       0, FF_ARRAY_ELEMS(mcc_weightings) - 1);

  1163.     return mcc_weightings[idx];

  1164. }

  1165. 

  1166. /** Read the channel data.

  1167.   */

  1168. static int read_channel_data(ALSDecContext *ctx, ALSChannelData *cd, int c)

  1169. {

  1170.     GetBitContext *gb       = &ctx->gb;

  1171.     ALSChannelData *current = cd;

  1172.     unsigned int channels   = ctx->avctx->channels;

  1173.     int entries             = 0;

  1174. 

  1175.     while (entries < channels && !(current->stop_flag = get_bits1(gb))) {

  1176.         current->master_channel = get_bits_long(gb, av_ceil_log2(channels));

  1177. 

  1178.         if (current->master_channel >= channels) {

  1179.             av_log(ctx->avctx, AV_LOG_ERROR, "Invalid master channel!\n");

  1180.             return AVERROR_INVALIDDATA;

  1181.         }

  1182. 

  1183.         if (current->master_channel != c) {

  1184.             current->time_diff_flag = get_bits1(gb);

  1185.             current->weighting[0]   = als_weighting(gb, 1, 16);

  1186.             current->weighting[1]   = als_weighting(gb, 2, 14);

  1187.             current->weighting[2]   = als_weighting(gb, 1, 16);

  1188. 

  1189.             if (current->time_diff_flag) {

  1190.                 current->weighting[3] = als_weighting(gb, 1, 16);

  1191.                 current->weighting[4] = als_weighting(gb, 1, 16);

  1192.                 current->weighting[5] = als_weighting(gb, 1, 16);

  1193. 

  1194.                 current->time_diff_sign  = get_bits1(gb);

  1195.                 current->time_diff_index = get_bits(gb, ctx->ltp_lag_length - 3) + 3;

  1196.             }

  1197.         }

  1198. 

  1199.         current++;

  1200.         entries++;

  1201.     }

  1202. 

  1203.     if (entries == channels) {

  1204.         av_log(ctx->avctx, AV_LOG_ERROR, "Damaged channel data!\n");

  1205.         return AVERROR_INVALIDDATA;

  1206.     }

  1207. 

  1208.     align_get_bits(gb);

  1209.     return 0;

  1210. }

  1211. 

  1212. 

  1213. /** Recursively reverts the inter-channel correlation for a block.

  1214.  */

  1215. static int revert_channel_correlation(ALSDecContext *ctx, ALSBlockData *bd,

  1216.                                        ALSChannelData **cd, int *reverted,

  1217.                                        unsigned int offset, int c)

  1218. {

  1219.     ALSChannelData *ch = cd[c];

  1220.     unsigned int   dep = 0;

  1221.     unsigned int channels = ctx->avctx->channels;

  1222. 

  1223.     if (reverted[c])

  1224.         return 0;

  1225. 

  1226.     reverted[c] = 1;

  1227. 

  1228.     while (dep < channels && !ch[dep].stop_flag) {

  1229.         revert_channel_correlation(ctx, bd, cd, reverted, offset,

  1230.                                    ch[dep].master_channel);

  1231. 

  1232.         dep++;

  1233.     }

  1234. 

  1235.     if (dep == channels) {

  1236.         av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel correlation!\n");

  1237.         return AVERROR_INVALIDDATA;

  1238.     }

  1239. 

  1240.     bd->const_block = ctx->const_block + c;

  1241.     bd->shift_lsbs  = ctx->shift_lsbs + c;

  1242.     bd->opt_order   = ctx->opt_order + c;

  1243.     bd->store_prev_samples = ctx->store_prev_samples + c;

  1244.     bd->use_ltp     = ctx->use_ltp + c;

  1245.     bd->ltp_lag     = ctx->ltp_lag + c;

  1246.     bd->ltp_gain    = ctx->ltp_gain[c];

  1247.     bd->lpc_cof     = ctx->lpc_cof[c];

  1248.     bd->quant_cof   = ctx->quant_cof[c];

  1249.     bd->raw_samples = ctx->raw_samples[c] + offset;

  1250. 

  1251.     dep = 0;

  1252.     while (!ch[dep].stop_flag) {

  1253.         unsigned int smp;

  1254.         unsigned int begin = 1;

  1255.         unsigned int end   = bd->block_length - 1;

  1256.         int64_t y;

  1257.         int32_t *master = ctx->raw_samples[ch[dep].master_channel] + offset;

  1258. 

  1259.         if (ch[dep].time_diff_flag) {

  1260.             int t = ch[dep].time_diff_index;

  1261. 

  1262.             if (ch[dep].time_diff_sign) {

  1263.                 t      = -t;

  1264.                 begin -= t;

  1265.             } else {

  1266.                 end   -= t;

  1267.             }

  1268. 

  1269.             for (smp = begin; smp < end; smp++) {

  1270.                 y  = (1 << 6) +

  1271.                      MUL64(ch[dep].weighting[0], master[smp - 1    ]) +

  1272.                      MUL64(ch[dep].weighting[1], master[smp        ]) +

  1273.                      MUL64(ch[dep].weighting[2], master[smp + 1    ]) +

  1274.                      MUL64(ch[dep].weighting[3], master[smp - 1 + t]) +

  1275.                      MUL64(ch[dep].weighting[4], master[smp     + t]) +

  1276.                      MUL64(ch[dep].weighting[5], master[smp + 1 + t]);

  1277. 

  1278.                 bd->raw_samples[smp] += y >> 7;

  1279.             }

  1280.         } else {

  1281.             for (smp = begin; smp < end; smp++) {

  1282.                 y  = (1 << 6) +

  1283.                      MUL64(ch[dep].weighting[0], master[smp - 1]) +

  1284.                      MUL64(ch[dep].weighting[1], master[smp    ]) +

  1285.                      MUL64(ch[dep].weighting[2], master[smp + 1]);

  1286. 

  1287.                 bd->raw_samples[smp] += y >> 7;

  1288.             }

  1289.         }

  1290. 

  1291.         dep++;

  1292.     }

  1293. 

  1294.     return 0;

  1295. }

  1296. 

  1297. 

  1298. /** Read the frame data.

  1299.  */

  1300. static int read_frame_data(ALSDecContext *ctx, unsigned int ra_frame)

  1301. {

  1302.     ALSSpecificConfig *sconf = &ctx->sconf;

  1303.     AVCodecContext *avctx    = ctx->avctx;

  1304.     GetBitContext *gb = &ctx->gb;

  1305.     unsigned int div_blocks[32];                ///< block sizes.

  1306.     unsigned int c;

  1307.     unsigned int js_blocks[2];

  1308.     uint32_t bs_info = 0;

  1309.     int ret;

  1310. 

  1311.     // skip the size of the ra unit if present in the frame

  1312.     if (sconf->ra_flag == RA_FLAG_FRAMES && ra_frame)

  1313.         skip_bits_long(gb, 32);

  1314. 

  1315.     if (sconf->mc_coding && sconf->joint_stereo) {

  1316.         ctx->js_switch = get_bits1(gb);

  1317.         align_get_bits(gb);

  1318.     }

  1319. 

  1320.     if (!sconf->mc_coding || ctx->js_switch) {

  1321.         int independent_bs = !sconf->joint_stereo;

  1322. 

  1323.         for (c = 0; c < avctx->channels; c++) {

  1324.             js_blocks[0] = 0;

  1325.             js_blocks[1] = 0;

  1326. 

  1327.             get_block_sizes(ctx, div_blocks, &bs_info);

  1328. 

  1329.             // if joint_stereo and block_switching is set, independent decoding

  1330.             // is signaled via the first bit of bs_info

  1331.             if (sconf->joint_stereo && sconf->block_switching)

  1332.                 if (bs_info >> 31)

  1333.                     independent_bs = 2;

  1334. 

  1335.             // if this is the last channel, it has to be decoded independently

  1336.             if (c == avctx->channels - 1)

  1337.                 independent_bs = 1;

  1338. 

  1339.             if (independent_bs) {

  1340.                 ret = decode_blocks_ind(ctx, ra_frame, c,

  1341.                                         div_blocks, js_blocks);

  1342.                 if (ret < 0)

  1343.                     return ret;

  1344.                 independent_bs--;

  1345.             } else {

  1346.                 ret = decode_blocks(ctx, ra_frame, c, div_blocks, js_blocks);

  1347.                 if (ret < 0)

  1348.                     return ret;

  1349. 

  1350.                 c++;

  1351.             }

  1352. 

  1353.             // store carryover raw samples

  1354.             memmove(ctx->raw_samples[c] - sconf->max_order,

  1355.                     ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1356.                     sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1357.         }

  1358.     } else { // multi-channel coding

  1359.         ALSBlockData   bd = { 0 };

  1360.         int            b, ret;

  1361.         int            *reverted_channels = ctx->reverted_channels;

  1362.         unsigned int   offset             = 0;

  1363. 

  1364.         for (c = 0; c < avctx->channels; c++)

  1365.             if (ctx->chan_data[c] < ctx->chan_data_buffer) {

  1366.                 av_log(ctx->avctx, AV_LOG_ERROR, "Invalid channel data!\n");

  1367.                 return AVERROR_INVALIDDATA;

  1368.             }

  1369. 

  1370.         memset(reverted_channels, 0, sizeof(*reverted_channels) * avctx->channels);

  1371. 

  1372.         bd.ra_block         = ra_frame;

  1373.         bd.prev_raw_samples = ctx->prev_raw_samples;

  1374. 

  1375.         get_block_sizes(ctx, div_blocks, &bs_info);

  1376. 

  1377.         for (b = 0; b < ctx->num_blocks; b++) {

  1378.             bd.block_length = div_blocks[b];

  1379. 

  1380.             for (c = 0; c < avctx->channels; c++) {

  1381.                 bd.const_block = ctx->const_block + c;

  1382.                 bd.shift_lsbs  = ctx->shift_lsbs + c;

  1383.                 bd.opt_order   = ctx->opt_order + c;

  1384.                 bd.store_prev_samples = ctx->store_prev_samples + c;

  1385.                 bd.use_ltp     = ctx->use_ltp + c;

  1386.                 bd.ltp_lag     = ctx->ltp_lag + c;

  1387.                 bd.ltp_gain    = ctx->ltp_gain[c];

  1388.                 bd.lpc_cof     = ctx->lpc_cof[c];

  1389.                 bd.quant_cof   = ctx->quant_cof[c];

  1390.                 bd.raw_samples = ctx->raw_samples[c] + offset;

  1391.                 bd.raw_other   = NULL;

  1392. 

  1393.                 if ((ret = read_block(ctx, &bd)) < 0)

  1394.                     return ret;

  1395.                 if ((ret = read_channel_data(ctx, ctx->chan_data[c], c)) < 0)

  1396.                     return ret;

  1397.             }

  1398. 

  1399.             for (c = 0; c < avctx->channels; c++) {

  1400.                 ret = revert_channel_correlation(ctx, &bd, ctx->chan_data,

  1401.                                                  reverted_channels, offset, c);

  1402.                 if (ret < 0)

  1403.                     return ret;

  1404.             }

  1405.             for (c = 0; c < avctx->channels; c++) {

  1406.                 bd.const_block = ctx->const_block + c;

  1407.                 bd.shift_lsbs  = ctx->shift_lsbs + c;

  1408.                 bd.opt_order   = ctx->opt_order + c;

  1409.                 bd.store_prev_samples = ctx->store_prev_samples + c;

  1410.                 bd.use_ltp     = ctx->use_ltp + c;

  1411.                 bd.ltp_lag     = ctx->ltp_lag + c;

  1412.                 bd.ltp_gain    = ctx->ltp_gain[c];

  1413.                 bd.lpc_cof     = ctx->lpc_cof[c];

  1414.                 bd.quant_cof   = ctx->quant_cof[c];

  1415.                 bd.raw_samples = ctx->raw_samples[c] + offset;

  1416.                 if ((ret = decode_block(ctx, &bd)) < 0)

  1417.                     return ret;

  1418.             }

  1419. 

  1420.             memset(reverted_channels, 0, avctx->channels * sizeof(*reverted_channels));

  1421.             offset      += div_blocks[b];

  1422.             bd.ra_block  = 0;

  1423.         }

  1424. 

  1425.         // store carryover raw samples

  1426.         for (c = 0; c < avctx->channels; c++)

  1427.             memmove(ctx->raw_samples[c] - sconf->max_order,

  1428.                     ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1429.                     sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1430.     }

  1431. 

  1432.     // TODO: read_diff_float_data

  1433. 

  1434.     return 0;

  1435. }

  1436. 

  1437. 

  1438. /** Decode an ALS frame.

  1439.  */

  1440. static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr,

  1441.                         AVPacket *avpkt)

  1442. {

  1443.     ALSDecContext *ctx       = avctx->priv_data;

  1444.     AVFrame *frame           = data;

  1445.     ALSSpecificConfig *sconf = &ctx->sconf;

  1446.     const uint8_t *buffer    = avpkt->data;

  1447.     int buffer_size          = avpkt->size;

  1448.     int invalid_frame, ret;

  1449.     unsigned int c, sample, ra_frame, bytes_read, shift;

  1450. 

  1451.     init_get_bits(&ctx->gb, buffer, buffer_size * 8);

  1452. 

  1453.     // In the case that the distance between random access frames is set to zero

  1454.     // (sconf->ra_distance == 0) no frame is treated as a random access frame.

  1455.     // For the first frame, if prediction is used, all samples used from the

  1456.     // previous frame are assumed to be zero.

  1457.     ra_frame = sconf->ra_distance && !(ctx->frame_id % sconf->ra_distance);

  1458. 

  1459.     // the last frame to decode might have a different length

  1460.     if (sconf->samples != 0xFFFFFFFF)

  1461.         ctx->cur_frame_length = FFMIN(sconf->samples - ctx->frame_id * (uint64_t) sconf->frame_length,

  1462.                                       sconf->frame_length);

  1463.     else

  1464.         ctx->cur_frame_length = sconf->frame_length;

  1465. 

  1466.     // decode the frame data

  1467.     if ((invalid_frame = read_frame_data(ctx, ra_frame)) < 0)

  1468.         av_log(ctx->avctx, AV_LOG_WARNING,

  1469.                "Reading frame data failed. Skipping RA unit.\n");

  1470. 

  1471.     ctx->frame_id++;

  1472. 

  1473.     /* get output buffer */

  1474.     frame->nb_samples = ctx->cur_frame_length;

  1475.     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) {

  1476.         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");

  1477.         return ret;

  1478.     }

  1479. 

  1480.     // transform decoded frame into output format

  1481.     #define INTERLEAVE_OUTPUT(bps)                                 \

  1482.     {                                                              \

  1483.         int##bps##_t *dest = (int##bps##_t*)frame->data[0];        \

  1484.         shift = bps - ctx->avctx->bits_per_raw_sample;             \

  1485.         for (sample = 0; sample < ctx->cur_frame_length; sample++) \

  1486.             for (c = 0; c < avctx->channels; c++)                  \

  1487.                 *dest++ = ctx->raw_samples[c][sample] << shift;    \

  1488.     }

  1489. 

  1490.     if (ctx->avctx->bits_per_raw_sample <= 16) {

  1491.         INTERLEAVE_OUTPUT(16)

  1492.     } else {

  1493.         INTERLEAVE_OUTPUT(32)

  1494.     }

  1495. 

  1496.     // update CRC

  1497.     if (sconf->crc_enabled && (avctx->err_recognition & AV_EF_CRCCHECK)) {

  1498.         int swap = HAVE_BIGENDIAN != sconf->msb_first;

  1499. 

  1500.         if (ctx->avctx->bits_per_raw_sample == 24) {

  1501.             int32_t *src = (int32_t *)frame->data[0];

  1502. 

  1503.             for (sample = 0;

  1504.                  sample < ctx->cur_frame_length * avctx->channels;

  1505.                  sample++) {

  1506.                 int32_t v;

  1507. 

  1508.                 if (swap)

  1509.                     v = av_bswap32(src[sample]);

  1510.                 else

  1511.                     v = src[sample];

  1512.                 if (!HAVE_BIGENDIAN)

  1513.                     v >>= 8;

  1514. 

  1515.                 ctx->crc = av_crc(ctx->crc_table, ctx->crc, (uint8_t*)(&v), 3);

  1516.             }

  1517.         } else {

  1518.             uint8_t *crc_source;

  1519. 

  1520.             if (swap) {

  1521.                 if (ctx->avctx->bits_per_raw_sample <= 16) {

  1522.                     int16_t *src  = (int16_t*) frame->data[0];

  1523.                     int16_t *dest = (int16_t*) ctx->crc_buffer;

  1524.                     for (sample = 0;

  1525.                          sample < ctx->cur_frame_length * avctx->channels;

  1526.                          sample++)

  1527.                         *dest++ = av_bswap16(src[sample]);

  1528.                 } else {

  1529.                     ctx->dsp.bswap_buf((uint32_t*)ctx->crc_buffer,

  1530.                                        (uint32_t *)frame->data[0],

  1531.                                        ctx->cur_frame_length * avctx->channels);

  1532.                 }

  1533.                 crc_source = ctx->crc_buffer;

  1534.             } else {

  1535.                 crc_source = frame->data[0];

  1536.             }

  1537. 

  1538.             ctx->crc = av_crc(ctx->crc_table, ctx->crc, crc_source,

  1539.                               ctx->cur_frame_length * avctx->channels *

  1540.                               av_get_bytes_per_sample(avctx->sample_fmt));

  1541.         }

  1542. 

  1543. 

  1544.         // check CRC sums if this is the last frame

  1545.         if (ctx->cur_frame_length != sconf->frame_length &&

  1546.             ctx->crc_org != ctx->crc) {

  1547.             av_log(avctx, AV_LOG_ERROR, "CRC error.\n");

  1548.         }

  1549.     }

  1550. 

  1551.     *got_frame_ptr = 1;

  1552. 

  1553.     bytes_read = invalid_frame ? buffer_size :

  1554.                                  (get_bits_count(&ctx->gb) + 7) >> 3;

  1555. 

  1556.     return bytes_read;

  1557. }

  1558. 

  1559. 

  1560. /** Uninitialize the ALS decoder.

  1561.  */

  1562. static av_cold int decode_end(AVCodecContext *avctx)

  1563. {

  1564.     ALSDecContext *ctx = avctx->priv_data;

  1565. 

  1566.     av_freep(&ctx->sconf.chan_pos);

  1567. 

  1568.     ff_bgmc_end(&ctx->bgmc_lut, &ctx->bgmc_lut_status);

  1569. 

  1570.     av_freep(&ctx->const_block);

  1571.     av_freep(&ctx->shift_lsbs);

  1572.     av_freep(&ctx->opt_order);

  1573.     av_freep(&ctx->store_prev_samples);

  1574.     av_freep(&ctx->use_ltp);

  1575.     av_freep(&ctx->ltp_lag);

  1576.     av_freep(&ctx->ltp_gain);

  1577.     av_freep(&ctx->ltp_gain_buffer);

  1578.     av_freep(&ctx->quant_cof);

  1579.     av_freep(&ctx->lpc_cof);

  1580.     av_freep(&ctx->quant_cof_buffer);

  1581.     av_freep(&ctx->lpc_cof_buffer);

  1582.     av_freep(&ctx->lpc_cof_reversed_buffer);

  1583.     av_freep(&ctx->prev_raw_samples);

  1584.     av_freep(&ctx->raw_samples);

  1585.     av_freep(&ctx->raw_buffer);

  1586.     av_freep(&ctx->chan_data);

  1587.     av_freep(&ctx->chan_data_buffer);

  1588.     av_freep(&ctx->reverted_channels);

  1589.     av_freep(&ctx->crc_buffer);

  1590. 

  1591.     return 0;

  1592. }

  1593. 

  1594. 

  1595. /** Initialize the ALS decoder.

  1596.  */

  1597. static av_cold int decode_init(AVCodecContext *avctx)

  1598. {

  1599.     unsigned int c;

  1600.     unsigned int channel_size;

  1601.     int num_buffers, ret;

  1602.     ALSDecContext *ctx = avctx->priv_data;

  1603.     ALSSpecificConfig *sconf = &ctx->sconf;

  1604.     ctx->avctx = avctx;

  1605. 

  1606.     if (!avctx->extradata) {

  1607.         av_log(avctx, AV_LOG_ERROR, "Missing required ALS extradata.\n");

  1608.         return AVERROR_INVALIDDATA;

  1609.     }

  1610. 

  1611.     if ((ret = read_specific_config(ctx)) < 0) {

  1612.         av_log(avctx, AV_LOG_ERROR, "Reading ALSSpecificConfig failed.\n");

  1613.         goto fail;

  1614.     }

  1615. 

  1616.     if ((ret = check_specific_config(ctx)) < 0) {

  1617.         goto fail;

  1618.     }

  1619. 

  1620.     if (sconf->bgmc) {

  1621.         ret = ff_bgmc_init(avctx, &ctx->bgmc_lut, &ctx->bgmc_lut_status);

  1622.         if (ret < 0)

  1623.             goto fail;

  1624.     }

  1625.     if (sconf->floating) {

  1626.         avctx->sample_fmt          = AV_SAMPLE_FMT_FLT;

  1627.         avctx->bits_per_raw_sample = 32;

  1628.     } else {

  1629.         avctx->sample_fmt          = sconf->resolution > 1

  1630.                                      ? AV_SAMPLE_FMT_S32 : AV_SAMPLE_FMT_S16;

  1631.         avctx->bits_per_raw_sample = (sconf->resolution + 1) * 8;

  1632.     }

  1633. 

  1634.     // set maximum Rice parameter for progressive decoding based on resolution

  1635.     // This is not specified in 14496-3 but actually done by the reference

  1636.     // codec RM22 revision 2.

  1637.     ctx->s_max = sconf->resolution > 1 ? 31 : 15;

  1638. 

  1639.     // set lag value for long-term prediction

  1640.     ctx->ltp_lag_length = 8 + (avctx->sample_rate >=  96000) +

  1641.                               (avctx->sample_rate >= 192000);

  1642. 

  1643.     // allocate quantized parcor coefficient buffer

  1644.     num_buffers = sconf->mc_coding ? avctx->channels : 1;

  1645. 

  1646.     ctx->quant_cof        = av_malloc(sizeof(*ctx->quant_cof) * num_buffers);

  1647.     ctx->lpc_cof          = av_malloc(sizeof(*ctx->lpc_cof)   * num_buffers);

  1648.     ctx->quant_cof_buffer = av_malloc(sizeof(*ctx->quant_cof_buffer) *

  1649.                                       num_buffers * sconf->max_order);

  1650.     ctx->lpc_cof_buffer   = av_malloc(sizeof(*ctx->lpc_cof_buffer) *

  1651.                                       num_buffers * sconf->max_order);

  1652.     ctx->lpc_cof_reversed_buffer = av_malloc(sizeof(*ctx->lpc_cof_buffer) *

  1653.                                              sconf->max_order);

  1654. 

  1655.     if (!ctx->quant_cof              || !ctx->lpc_cof        ||

  1656.         !ctx->quant_cof_buffer       || !ctx->lpc_cof_buffer ||

  1657.         !ctx->lpc_cof_reversed_buffer) {

  1658.         av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1659.         ret = AVERROR(ENOMEM);

  1660.         goto fail;

  1661.     }

  1662. 

  1663.     // assign quantized parcor coefficient buffers

  1664.     for (c = 0; c < num_buffers; c++) {

  1665.         ctx->quant_cof[c] = ctx->quant_cof_buffer + c * sconf->max_order;

  1666.         ctx->lpc_cof[c]   = ctx->lpc_cof_buffer   + c * sconf->max_order;

  1667.     }

  1668. 

  1669.     // allocate and assign lag and gain data buffer for ltp mode

  1670.     ctx->const_block     = av_malloc (sizeof(*ctx->const_block) * num_buffers);

  1671.     ctx->shift_lsbs      = av_malloc (sizeof(*ctx->shift_lsbs)  * num_buffers);

  1672.     ctx->opt_order       = av_malloc (sizeof(*ctx->opt_order)   * num_buffers);

  1673.     ctx->store_prev_samples = av_malloc(sizeof(*ctx->store_prev_samples) * num_buffers);

  1674.     ctx->use_ltp         = av_mallocz(sizeof(*ctx->use_ltp)  * num_buffers);

  1675.     ctx->ltp_lag         = av_malloc (sizeof(*ctx->ltp_lag)  * num_buffers);

  1676.     ctx->ltp_gain        = av_malloc (sizeof(*ctx->ltp_gain) * num_buffers);

  1677.     ctx->ltp_gain_buffer = av_malloc (sizeof(*ctx->ltp_gain_buffer) *

  1678.                                       num_buffers * 5);

  1679. 

  1680.     if (!ctx->const_block || !ctx->shift_lsbs ||

  1681.         !ctx->opt_order || !ctx->store_prev_samples ||

  1682.         !ctx->use_ltp  || !ctx->ltp_lag ||

  1683.         !ctx->ltp_gain || !ctx->ltp_gain_buffer) {

  1684.         av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1685.         ret = AVERROR(ENOMEM);

  1686.         goto fail;

  1687.     }

  1688. 

  1689.     for (c = 0; c < num_buffers; c++)

  1690.         ctx->ltp_gain[c] = ctx->ltp_gain_buffer + c * 5;

  1691. 

  1692.     // allocate and assign channel data buffer for mcc mode

  1693.     if (sconf->mc_coding) {

  1694.         ctx->chan_data_buffer  = av_malloc(sizeof(*ctx->chan_data_buffer) *

  1695.                                            num_buffers * num_buffers);

  1696.         ctx->chan_data         = av_malloc(sizeof(*ctx->chan_data) *

  1697.                                            num_buffers);

  1698.         ctx->reverted_channels = av_malloc(sizeof(*ctx->reverted_channels) *

  1699.                                            num_buffers);

  1700. 

  1701.         if (!ctx->chan_data_buffer || !ctx->chan_data || !ctx->reverted_channels) {

  1702.             av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1703.             ret = AVERROR(ENOMEM);

  1704.             goto fail;

  1705.         }

  1706. 

  1707.         for (c = 0; c < num_buffers; c++)

  1708.             ctx->chan_data[c] = ctx->chan_data_buffer + c * num_buffers;

  1709.     } else {

  1710.         ctx->chan_data         = NULL;

  1711.         ctx->chan_data_buffer  = NULL;

  1712.         ctx->reverted_channels = NULL;

  1713.     }

  1714. 

  1715.     channel_size      = sconf->frame_length + sconf->max_order;

  1716. 

  1717.     ctx->prev_raw_samples = av_malloc (sizeof(*ctx->prev_raw_samples) * sconf->max_order);

  1718.     ctx->raw_buffer       = av_mallocz(sizeof(*ctx->     raw_buffer)  * avctx->channels * channel_size);

  1719.     ctx->raw_samples      = av_malloc (sizeof(*ctx->     raw_samples) * avctx->channels);

  1720. 

  1721.     // allocate previous raw sample buffer

  1722.     if (!ctx->prev_raw_samples || !ctx->raw_buffer|| !ctx->raw_samples) {

  1723.         av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1724.         ret = AVERROR(ENOMEM);

  1725.         goto fail;

  1726.     }

  1727. 

  1728.     // assign raw samples buffers

  1729.     ctx->raw_samples[0] = ctx->raw_buffer + sconf->max_order;

  1730.     for (c = 1; c < avctx->channels; c++)

  1731.         ctx->raw_samples[c] = ctx->raw_samples[c - 1] + channel_size;

  1732. 

  1733.     // allocate crc buffer

  1734.     if (HAVE_BIGENDIAN != sconf->msb_first && sconf->crc_enabled &&

  1735.         (avctx->err_recognition & AV_EF_CRCCHECK)) {

  1736.         ctx->crc_buffer = av_malloc(sizeof(*ctx->crc_buffer) *

  1737.                                     ctx->cur_frame_length *

  1738.                                     avctx->channels *

  1739.                                     av_get_bytes_per_sample(avctx->sample_fmt));

  1740.         if (!ctx->crc_buffer) {

  1741.             av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1742.             ret = AVERROR(ENOMEM);

  1743.             goto fail;

  1744.         }

  1745.     }

  1746. 

  1747.     ff_dsputil_init(&ctx->dsp, avctx);

  1748. 

  1749.     return 0;

  1750. 

  1751. fail:

  1752.     decode_end(avctx);

  1753.     return ret;

  1754. }

  1755. 

  1756. 

  1757. /** Flush (reset) the frame ID after seeking.

  1758.  */

  1759. static av_cold void flush(AVCodecContext *avctx)

  1760. {

  1761.     ALSDecContext *ctx = avctx->priv_data;

  1762. 

  1763.     ctx->frame_id = 0;

  1764. }

  1765. 

  1766. 

  1767. AVCodec ff_als_decoder = {

  1768.     .name           = "als",

  1769.     .long_name      = NULL_IF_CONFIG_SMALL("MPEG-4 Audio Lossless Coding (ALS)"),

  1770.     .type           = AVMEDIA_TYPE_AUDIO,

  1771.     .id             = AV_CODEC_ID_MP4ALS,

  1772.     .priv_data_size = sizeof(ALSDecContext),

  1773.     .init           = decode_init,

  1774.     .close          = decode_end,

  1775.     .decode         = decode_frame,

  1776.     .flush          = flush,

  1777.     .capabilities   = CODEC_CAP_SUBFRAMES | CODEC_CAP_DR1,

  1778. };