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FFmpeg/libavcodec/alsdec.c

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  1. /*

  2.  * MPEG-4 ALS decoder

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

  4.  *

  5.  * This file is part of FFmpeg.

  6.  *

  7.  * FFmpeg is free software; you can redistribute it and/or

  8.  * modify it under the terms of the GNU Lesser General Public

  9.  * License as published by the Free Software Foundation; either

  10.  * version 2.1 of the License, or (at your option) any later version.

  11.  *

  12.  * FFmpeg is distributed in the hope that it will be useful,

  13.  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  14.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

  15.  * Lesser General Public License for more details.

  16.  *

  17.  * You should have received a copy of the GNU Lesser General Public

  18.  * License along with FFmpeg; if not, write to the Free Software

  19.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

  20.  */

  21. 

  22. /**

  23.  * @file libavcodec/alsdec.c

  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. 

  38. #include <stdint.h>

  39. 

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

  41.  *  indices of scaled PARCOR values. The table choosen is set globally

  42.  *  by the encoder and stored in ALSSpecificConfig.

  43.  */

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

  45.     { {-52, 4}, {-29, 5}, {-31, 4}, { 19, 4}, {-16, 4},

  46.       { 12, 3}, { -7, 3}, {  9, 3}, { -5, 3}, {  6, 3},

  47.       { -4, 3}, {  3, 3}, { -3, 2}, {  3, 2}, { -2, 2},

  48.       {  3, 2}, { -1, 2}, {  2, 2}, { -1, 2}, {  2, 2} },

  49.     { {-58, 3}, {-42, 4}, {-46, 4}, { 37, 5}, {-36, 4},

  50.       { 29, 4}, {-29, 4}, { 25, 4}, {-23, 4}, { 20, 4},

  51.       {-17, 4}, { 16, 4}, {-12, 4}, { 12, 3}, {-10, 4},

  52.       {  7, 3}, { -4, 4}, {  3, 3}, { -1, 3}, {  1, 3} },

  53.     { {-59, 3}, {-45, 5}, {-50, 4}, { 38, 4}, {-39, 4},

  54.       { 32, 4}, {-30, 4}, { 25, 3}, {-23, 3}, { 20, 3},

  55.       {-20, 3}, { 16, 3}, {-13, 3}, { 10, 3}, { -7, 3},

  56.       {  3, 3}, {  0, 3}, { -1, 3}, {  2, 3}, { -1, 2} }

  57. };

  58. 

  59. 

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

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

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

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

  64.  */

  65. static const int16_t parcor_scaled_values[] = {

  66.     -1048544 / 32, -1048288 / 32, -1047776 / 32, -1047008 / 32,

  67.     -1045984 / 32, -1044704 / 32, -1043168 / 32, -1041376 / 32,

  68.     -1039328 / 32, -1037024 / 32, -1034464 / 32, -1031648 / 32,

  69.     -1028576 / 32, -1025248 / 32, -1021664 / 32, -1017824 / 32,

  70.     -1013728 / 32, -1009376 / 32, -1004768 / 32,  -999904 / 32,

  71.      -994784 / 32,  -989408 / 32,  -983776 / 32,  -977888 / 32,

  72.      -971744 / 32,  -965344 / 32,  -958688 / 32,  -951776 / 32,

  73.      -944608 / 32,  -937184 / 32,  -929504 / 32,  -921568 / 32,

  74.      -913376 / 32,  -904928 / 32,  -896224 / 32,  -887264 / 32,

  75.      -878048 / 32,  -868576 / 32,  -858848 / 32,  -848864 / 32,

  76.      -838624 / 32,  -828128 / 32,  -817376 / 32,  -806368 / 32,

  77.      -795104 / 32,  -783584 / 32,  -771808 / 32,  -759776 / 32,

  78.      -747488 / 32,  -734944 / 32,  -722144 / 32,  -709088 / 32,

  79.      -695776 / 32,  -682208 / 32,  -668384 / 32,  -654304 / 32,

  80.      -639968 / 32,  -625376 / 32,  -610528 / 32,  -595424 / 32,

  81.      -580064 / 32,  -564448 / 32,  -548576 / 32,  -532448 / 32,

  82.      -516064 / 32,  -499424 / 32,  -482528 / 32,  -465376 / 32,

  83.      -447968 / 32,  -430304 / 32,  -412384 / 32,  -394208 / 32,

  84.      -375776 / 32,  -357088 / 32,  -338144 / 32,  -318944 / 32,

  85.      -299488 / 32,  -279776 / 32,  -259808 / 32,  -239584 / 32,

  86.      -219104 / 32,  -198368 / 32,  -177376 / 32,  -156128 / 32,

  87.      -134624 / 32,  -112864 / 32,   -90848 / 32,   -68576 / 32,

  88.       -46048 / 32,   -23264 / 32,     -224 / 32,    23072 / 32,

  89.        46624 / 32,    70432 / 32,    94496 / 32,   118816 / 32,

  90.       143392 / 32,   168224 / 32,   193312 / 32,   218656 / 32,

  91.       244256 / 32,   270112 / 32,   296224 / 32,   322592 / 32,

  92.       349216 / 32,   376096 / 32,   403232 / 32,   430624 / 32,

  93.       458272 / 32,   486176 / 32,   514336 / 32,   542752 / 32,

  94.       571424 / 32,   600352 / 32,   629536 / 32,   658976 / 32,

  95.       688672 / 32,   718624 / 32,   748832 / 32,   779296 / 32,

  96.       810016 / 32,   840992 / 32,   872224 / 32,   903712 / 32,

  97.       935456 / 32,   967456 / 32,   999712 / 32,  1032224 / 32

  98. };

  99. 

  100. 

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

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

  103.  */

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

  105.     { 0,  8, 16,  24},

  106.     {32, 40, 48,  56},

  107.     {64, 70, 76,  82},

  108.     {88, 92, 96, 100}

  109. };

  110. 

  111. 

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

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

  114.  */

  115. static const int16_t mcc_weightings[] = {

  116.     204,  192,  179,  166,  153,  140,  128,  115,

  117.     102,   89,   76,   64,   51,   38,   25,   12,

  118.       0,  -12,  -25,  -38,  -51,  -64,  -76,  -89,

  119.    -102, -115, -128, -140, -153, -166, -179, -192

  120. };

  121. 

  122. 

  123. enum RA_Flag {

  124.     RA_FLAG_NONE,

  125.     RA_FLAG_FRAMES,

  126.     RA_FLAG_HEADER

  127. };

  128. 

  129. 

  130. typedef struct {

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  151.     uint32_t header_size;     ///< header size of original audio file in bytes, provided for debugging

  152.     uint32_t trailer_size;    ///< trailer size of original audio file in bytes, provided for debugging

  153. } ALSSpecificConfig;

  154. 

  155. 

  156. typedef struct {

  157.     int stop_flag;

  158.     int master_channel;

  159.     int time_diff_flag;

  160.     int time_diff_sign;

  161.     int time_diff_index;

  162.     int weighting[6];

  163. } ALSChannelData;

  164. 

  165. 

  166. typedef struct {

  167.     AVCodecContext *avctx;

  168.     ALSSpecificConfig sconf;

  169.     GetBitContext gb;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  190. } ALSDecContext;

  191. 

  192. 

  193. typedef struct {

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  210. } ALSBlockData;

  211. 

  212. 

  213. static av_cold void dprint_specific_config(ALSDecContext *ctx)

  214. {

  215. #ifdef DEBUG

  216.     AVCodecContext *avctx    = ctx->avctx;

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

  218. 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  239. #endif

  240. }

  241. 

  242. 

  243. /** Reads an ALSSpecificConfig from a buffer into the output struct.

  244.  */

  245. static av_cold int read_specific_config(ALSDecContext *ctx)

  246. {

  247.     GetBitContext gb;

  248.     uint64_t ht_size;

  249.     int i, config_offset, crc_enabled;

  250.     MPEG4AudioConfig m4ac;

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

  252.     AVCodecContext *avctx    = ctx->avctx;

  253.     uint32_t als_id;

  254. 

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

  256. 

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

  258.                                              avctx->extradata_size);

  259. 

  260.     if (config_offset < 0)

  261.         return -1;

  262. 

  263.     skip_bits_long(&gb, config_offset);

  264. 

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

  266.         return -1;

  267. 

  268.     // read the fixed items

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

  270.     avctx->sample_rate          = m4ac.sample_rate;

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

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

  273.     avctx->channels             = m4ac.channels;

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

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

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

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

  278.     skip_bits1(&gb);         // skip msb_first

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  293.     crc_enabled                 = get_bits1(&gb);

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

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

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

  297. 

  298. 

  299.     // check for ALSSpecificConfig struct

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

  301.         return -1;

  302. 

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

  304. 

  305.     // read channel config

  306.     if (sconf->chan_config)

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

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

  309. 

  310. 

  311.     // read channel sorting

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

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

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

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

  316.             return -1;

  317. 

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

  319.             return AVERROR(ENOMEM);

  320. 

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

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

  323. 

  324.         align_get_bits(&gb);

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

  326.     } else {

  327.         sconf->chan_sort = 0;

  328.     }

  329. 

  330. 

  331.     // read fixed header and trailer sizes,

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

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

  334.         return -1;

  335. 

  336.     sconf->header_size  = get_bits_long(&gb, 32);

  337.     sconf->trailer_size = get_bits_long(&gb, 32);

  338.     if (sconf->header_size  == 0xFFFFFFFF)

  339.         sconf->header_size  = 0;

  340.     if (sconf->trailer_size == 0xFFFFFFFF)

  341.         sconf->trailer_size = 0;

  342. 

  343.     ht_size = ((int64_t)(sconf->header_size) + (int64_t)(sconf->trailer_size)) << 3;

  344. 

  345. 

  346.     // skip the header and trailer data

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

  348.         return -1;

  349. 

  350.     if (ht_size > INT32_MAX)

  351.         return -1;

  352. 

  353.     skip_bits_long(&gb, ht_size);

  354. 

  355. 

  356.     // skip the crc data

  357.     if (crc_enabled) {

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

  359.             return -1;

  360. 

  361.         skip_bits_long(&gb, 32);

  362.     }

  363. 

  364. 

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

  366. 

  367.     dprint_specific_config(ctx);

  368. 

  369.     return 0;

  370. }

  371. 

  372. 

  373. /** Checks the ALSSpecificConfig for unsupported features.

  374.  */

  375. static int check_specific_config(ALSDecContext *ctx)

  376. {

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

  378.     int error = 0;

  379. 

  380.     // report unsupported feature and set error value

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

  382.     {                                                   \

  383.         if (cond) {                                     \

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

  385.             error = errval;                             \

  386.         }                                               \

  387.     }

  388. 

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

  390.     MISSING_ERR(sconf->bgmc,                 "BGMC entropy decoding",       -1);

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

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

  393. 

  394.     return error;

  395. }

  396. 

  397. 

  398. /** Parses the bs_info field to extract the block partitioning used in

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

  400.  */

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

  402.                           unsigned int div, unsigned int **div_blocks,

  403.                           unsigned int *num_blocks)

  404. {

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

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

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

  408.         n   *= 2;

  409.         div += 1;

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

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

  412.     } else {

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

  414.         // (bit implicitly not set)

  415.         **div_blocks = div;

  416.         (*div_blocks)++;

  417.         (*num_blocks)++;

  418.     }

  419. }

  420. 

  421. 

  422. /** Reads and decodes a Rice codeword.

  423.  */

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

  425. {

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

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

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

  429. 

  430.     if (k > 1) {

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

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

  433.     } else if (!k) {

  434.         q >>= 1;

  435.     }

  436.     return r ? q : ~q;

  437. }

  438. 

  439. 

  440. /** Converts PARCOR coefficient k to direct filter coefficient.

  441.  */

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

  443. {

  444.     int i, j;

  445. 

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

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

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

  449.         cof[i]  += tmp1;

  450.     }

  451.     if (i == j)

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

  453. 

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

  455. }

  456. 

  457. 

  458. /** Reads block switching field if necessary and sets actual block sizes.

  459.  *  Also assures that the block sizes of the last frame correspond to the

  460.  *  actual number of samples.

  461.  */

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

  463.                             uint32_t *bs_info)

  464. {

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

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

  467.     unsigned int *ptr_div_blocks = div_blocks;

  468.     unsigned int b;

  469. 

  470.     if (sconf->block_switching) {

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

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

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

  474.     }

  475. 

  476.     ctx->num_blocks = 0;

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

  478. 

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

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

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

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

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

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

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

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

  487.     // codec RM22 revision 2.

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

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

  490.     // of 14496-3.

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

  492.     // frame.

  493. 

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

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

  496. 

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

  498.         unsigned int remaining = ctx->cur_frame_length;

  499. 

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

  501.             if (remaining < div_blocks[b]) {

  502.                 div_blocks[b] = remaining;

  503.                 ctx->num_blocks = b + 1;

  504.                 break;

  505.             }

  506. 

  507.             remaining -= div_blocks[b];

  508.         }

  509.     }

  510. }

  511. 

  512. 

  513. /** Reads the block data for a constant block

  514.  */

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

  516. {

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

  518.     AVCodecContext *avctx    = ctx->avctx;

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

  520. 

  521.     bd->const_val    = 0;

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

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

  524. 

  525.     // skip 5 reserved bits

  526.     skip_bits(gb, 5);

  527. 

  528.     if (bd->const_block) {

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

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

  531.     }

  532. 

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

  534.     bd->const_block = 1;

  535. }

  536. 

  537. 

  538. /** Decodes the block data for a constant block

  539.  */

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

  541. {

  542.     int      smp = bd->block_length;

  543.     int32_t  val = bd->const_val;

  544.     int32_t *dst = bd->raw_samples;

  545. 

  546.     // write raw samples into buffer

  547.     for (; smp; smp--)

  548.         *dst++ = val;

  549. }

  550. 

  551. 

  552. /** Reads the block data for a non-constant block

  553.  */

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

  555. {

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

  557.     AVCodecContext *avctx    = ctx->avctx;

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

  559.     unsigned int k;

  560.     unsigned int s[8];

  561.     unsigned int sub_blocks, log2_sub_blocks, sb_length;

  562.     unsigned int start      = 0;

  563.     unsigned int opt_order;

  564.     int          sb;

  565.     int32_t      *quant_cof = bd->quant_cof;

  566. 

  567. 

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

  569.     bd->const_block = 0;

  570. 

  571.     bd->opt_order   = 1;

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

  573. 

  574.     opt_order       = bd->opt_order;

  575. 

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

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

  578.         log2_sub_blocks = 0;

  579.     } else {

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

  581.             log2_sub_blocks = get_bits(gb, 2);

  582.         else

  583.             log2_sub_blocks = 2 * get_bits1(gb);

  584.     }

  585. 

  586.     sub_blocks = 1 << log2_sub_blocks;

  587. 

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

  589.     // block_length must be evenly divisible by sub_blocks

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

  591.         av_log(avctx, AV_LOG_WARNING,

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

  593.         return -1;

  594.     }

  595. 

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

  597. 

  598. 

  599.     if (sconf->bgmc) {

  600.         // TODO: BGMC mode

  601.     } else {

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

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

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

  605.     }

  606. 

  607.     if (get_bits1(gb))

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

  609. 

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

  611. 

  612. 

  613.     if (!sconf->rlslms) {

  614.         if (sconf->adapt_order) {

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

  616.                                                 2, sconf->max_order + 1));

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

  618.         } else {

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

  620.         }

  621. 

  622.         opt_order = bd->opt_order;

  623. 

  624.         if (opt_order) {

  625.             int add_base;

  626. 

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

  628.                 add_base = 0x7F;

  629. 

  630.                 // read coefficient 0

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

  632. 

  633.                 // read coefficient 1

  634.                 if (opt_order > 1)

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

  636. 

  637.                 // read coefficients 2 to opt_order

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

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

  640.             } else {

  641.                 int k_max;

  642.                 add_base = 1;

  643. 

  644.                 // read coefficient 0 to 19

  645.                 k_max = FFMIN(opt_order, 20);

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

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

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

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

  650.                 }

  651. 

  652.                 // read coefficients 20 to 126

  653.                 k_max = FFMIN(opt_order, 127);

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

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

  656. 

  657.                 // read coefficients 127 to opt_order

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

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

  660. 

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

  662. 

  663.                 if (opt_order > 1)

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

  665.             }

  666. 

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

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

  669.         }

  670.     }

  671. 

  672.     // read LTP gain and lag values

  673.     if (sconf->long_term_prediction) {

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

  675. 

  676.         if (*bd->use_ltp) {

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

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

  679. 

  680.             bd->ltp_gain[2]   = ltp_gain_values[get_unary(gb, 0, 4)][get_bits(gb, 2)];

  681. 

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

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

  684. 

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

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

  687.         }

  688.     }

  689. 

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

  691.     if (bd->ra_block) {

  692.         if (opt_order)

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

  694.         if (opt_order > 1)

  695.             bd->raw_samples[1] = decode_rice(gb, s[0] + 3);

  696.         if (opt_order > 2)

  697.             bd->raw_samples[2] = decode_rice(gb, s[0] + 1);

  698. 

  699.         start = FFMIN(opt_order, 3);

  700.     }

  701. 

  702.     // read all residuals

  703.     if (sconf->bgmc) {

  704.         // TODO: BGMC mode

  705.     } else {

  706.         int32_t *current_res = bd->raw_samples + start;

  707. 

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

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

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

  711.      }

  712. 

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

  714.         align_get_bits(gb);

  715. 

  716.     return 0;

  717. }

  718. 

  719. 

  720. /** Decodes the block data for a non-constant block

  721.  */

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

  723. {

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

  725.     unsigned int block_length = bd->block_length;

  726.     unsigned int smp = 0;

  727.     unsigned int k;

  728.     int opt_order             = bd->opt_order;

  729.     int sb;

  730.     int64_t y;

  731.     int32_t *quant_cof        = bd->quant_cof;

  732.     int32_t *lpc_cof          = bd->lpc_cof;

  733.     int32_t *raw_samples      = bd->raw_samples;

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

  735.     int32_t *lpc_cof_reversed = ctx->lpc_cof_reversed_buffer;

  736. 

  737.     // reverse long-term prediction

  738.     if (*bd->use_ltp) {

  739.         int ltp_smp;

  740. 

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

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

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

  744.             int end    = center + 3;

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

  746.             int base;

  747. 

  748.             y = 1 << 6;

  749. 

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

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

  752. 

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

  754.         }

  755.     }

  756. 

  757.     // reconstruct all samples from residuals

  758.     if (bd->ra_block) {

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

  760.             y = 1 << 19;

  761. 

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

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

  764. 

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

  766.             parcor_to_lpc(smp, quant_cof, lpc_cof);

  767.         }

  768.     } else {

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

  770.             parcor_to_lpc(k, quant_cof, lpc_cof);

  771. 

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

  773.         if (bd->store_prev_samples)

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

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

  776. 

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

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

  779.             int32_t *left, *right;

  780. 

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

  782.                 left  = raw_samples;

  783.                 right = bd->raw_other;

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

  785.                 left  = bd->raw_other;

  786.                 right = raw_samples;

  787.             }

  788. 

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

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

  791.         }

  792. 

  793.         // reconstruct shifted signal

  794.         if (bd->shift_lsbs)

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

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

  797.     }

  798. 

  799.     // reverse linear prediction coefficients for efficiency

  800.     lpc_cof = lpc_cof + opt_order;

  801. 

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

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

  804. 

  805.     // reconstruct raw samples

  806.     raw_samples = bd->raw_samples + smp;

  807.     lpc_cof     = lpc_cof_reversed + opt_order;

  808. 

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

  810.         y = 1 << 19;

  811. 

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

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

  814. 

  815.         *raw_samples -= y >> 20;

  816.     }

  817. 

  818.     raw_samples = bd->raw_samples;

  819. 

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

  821.     if (bd->store_prev_samples)

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

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

  824. 

  825.     return 0;

  826. }

  827. 

  828. 

  829. /** Reads the block data.

  830.  */

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

  832. {

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

  834. 

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

  836.     if (get_bits1(gb)) {

  837.         if (read_var_block_data(ctx, bd))

  838.             return -1;

  839.     } else {

  840.         read_const_block_data(ctx, bd);

  841.     }

  842. 

  843.     return 0;

  844. }

  845. 

  846. 

  847. /** Decodes the block data.

  848.  */

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

  850. {

  851.     unsigned int smp;

  852. 

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

  854.     if (bd->const_block)

  855.         decode_const_block_data(ctx, bd);

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

  857.         return -1;

  858. 

  859.     // TODO: read RLSLMS extension data

  860. 

  861.     if (bd->shift_lsbs)

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

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

  864. 

  865.     return 0;

  866. }

  867. 

  868. 

  869. /** Reads and decodes block data successively.

  870.  */

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

  872. {

  873.     int ret;

  874. 

  875.     ret = read_block(ctx, bd);

  876. 

  877.     if (ret)

  878.         return ret;

  879. 

  880.     ret = decode_block(ctx, bd);

  881. 

  882.     return ret;

  883. }

  884. 

  885. 

  886. /** Computes the number of samples left to decode for the current frame and

  887.  *  sets these samples to zero.

  888.  */

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

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

  891. {

  892.     unsigned int count = 0;

  893. 

  894.     while (b < b_max)

  895.         count += div_blocks[b];

  896. 

  897.     if (count)

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

  899. }

  900. 

  901. 

  902. /** Decodes blocks independently.

  903.  */

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

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

  906.                              unsigned int *js_blocks)

  907. {

  908.     unsigned int b;

  909.     ALSBlockData bd;

  910. 

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

  912. 

  913.     bd.ra_block         = ra_frame;

  914.     bd.use_ltp          = ctx->use_ltp;

  915.     bd.ltp_lag          = ctx->ltp_lag;

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

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

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

  919.     bd.prev_raw_samples = ctx->prev_raw_samples;

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

  921. 

  922. 

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

  924.         bd.shift_lsbs       = 0;

  925.         bd.block_length     = div_blocks[b];

  926. 

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

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

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

  930.             return -1;

  931.         }

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

  933.         bd.ra_block     = 0;

  934.     }

  935. 

  936.     return 0;

  937. }

  938. 

  939. 

  940. /** Decodes blocks dependently.

  941.  */

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

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

  944.                          unsigned int *js_blocks)

  945. {

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

  947.     unsigned int offset = 0;

  948.     unsigned int b;

  949.     ALSBlockData bd[2];

  950. 

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

  952. 

  953.     bd[0].ra_block         = ra_frame;

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

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

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

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

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

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

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

  961. 

  962.     bd[1].ra_block         = ra_frame;

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

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

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

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

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

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

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

  970. 

  971.     // decode all blocks

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

  973.         unsigned int s;

  974. 

  975.         bd[0].shift_lsbs   = 0;

  976.         bd[1].shift_lsbs   = 0;

  977. 

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

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

  980. 

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

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

  983. 

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

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

  986. 

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

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

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

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

  991.             return -1;

  992.         }

  993. 

  994.         // reconstruct joint-stereo blocks

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

  996.             if (bd[1].js_blocks)

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

  998. 

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

  1000.                 bd[0].raw_samples[s] = bd[1].raw_samples[s] - bd[0].raw_samples[s];

  1001.         } else if (bd[1].js_blocks) {

  1002.             for (s = 0; s < div_blocks[b]; s++)

  1003.                 bd[1].raw_samples[s] = bd[1].raw_samples[s] + bd[0].raw_samples[s];

  1004.         }

  1005. 

  1006.         offset  += div_blocks[b];

  1007.         bd[0].ra_block = 0;

  1008.         bd[1].ra_block = 0;

  1009.     }

  1010. 

  1011.     // store carryover raw samples,

  1012.     // the others channel raw samples are stored by the calling function.

  1013.     memmove(ctx->raw_samples[c] - sconf->max_order,

  1014.             ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1015.             sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1016. 

  1017.     return 0;

  1018. }

  1019. 

  1020. 

  1021. /** Reads the channel data.

  1022.   */

  1023. static int read_channel_data(ALSDecContext *ctx, ALSChannelData *cd, int c)

  1024. {

  1025.     GetBitContext *gb       = &ctx->gb;

  1026.     ALSChannelData *current = cd;

  1027.     unsigned int channels   = ctx->avctx->channels;

  1028.     int entries             = 0;

  1029. 

  1030.     while (entries < channels && !(current->stop_flag = get_bits1(gb))) {

  1031.         current->master_channel = get_bits_long(gb, av_ceil_log2(channels));

  1032. 

  1033.         if (current->master_channel >= channels) {

  1034.             av_log(ctx->avctx, AV_LOG_ERROR, "Invalid master channel!\n");

  1035.             return -1;

  1036.         }

  1037. 

  1038.         if (current->master_channel != c) {

  1039.             current->time_diff_flag = get_bits1(gb);

  1040.             current->weighting[0]   = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 32)];

  1041.             current->weighting[1]   = mcc_weightings[av_clip(decode_rice(gb, 2) + 14, 0, 32)];

  1042.             current->weighting[2]   = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 32)];

  1043. 

  1044.             if (current->time_diff_flag) {

  1045.                 current->weighting[3] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 32)];

  1046.                 current->weighting[4] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 32)];

  1047.                 current->weighting[5] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 32)];

  1048. 

  1049.                 current->time_diff_sign  = get_bits1(gb);

  1050.                 current->time_diff_index = get_bits(gb, ctx->ltp_lag_length - 3) + 3;

  1051.             }

  1052.         }

  1053. 

  1054.         current++;

  1055.         entries++;

  1056.     }

  1057. 

  1058.     if (entries == channels) {

  1059.         av_log(ctx->avctx, AV_LOG_ERROR, "Damaged channel data!\n");

  1060.         return -1;

  1061.     }

  1062. 

  1063.     align_get_bits(gb);

  1064.     return 0;

  1065. }

  1066. 

  1067. 

  1068. /** Recursively reverts the inter-channel correlation for a block.

  1069.  */

  1070. static int revert_channel_correlation(ALSDecContext *ctx, ALSBlockData *bd,

  1071.                                        ALSChannelData **cd, int *reverted,

  1072.                                        unsigned int offset, int c)

  1073. {

  1074.     ALSChannelData *ch = cd[c];

  1075.     unsigned int   dep = 0;

  1076.     unsigned int channels = ctx->avctx->channels;

  1077. 

  1078.     if (reverted[c])

  1079.         return 0;

  1080. 

  1081.     reverted[c] = 1;

  1082. 

  1083.     while (dep < channels && !ch[dep].stop_flag) {

  1084.         revert_channel_correlation(ctx, bd, cd, reverted, offset,

  1085.                                    ch[dep].master_channel);

  1086. 

  1087.         dep++;

  1088.     }

  1089. 

  1090.     if (dep == channels) {

  1091.         av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel correlation!\n");

  1092.         return -1;

  1093.     }

  1094. 

  1095.     bd->use_ltp     = ctx->use_ltp + c;

  1096.     bd->ltp_lag     = ctx->ltp_lag + c;

  1097.     bd->ltp_gain    = ctx->ltp_gain[c];

  1098.     bd->lpc_cof     = ctx->lpc_cof[c];

  1099.     bd->quant_cof   = ctx->quant_cof[c];

  1100.     bd->raw_samples = ctx->raw_samples[c] + offset;

  1101. 

  1102.     dep = 0;

  1103.     while (!ch[dep].stop_flag) {

  1104.         unsigned int smp;

  1105.         unsigned int begin = 1;

  1106.         unsigned int end   = bd->block_length - 1;

  1107.         int64_t y;

  1108.         int32_t *master = ctx->raw_samples[ch[dep].master_channel] + offset;

  1109. 

  1110.         if (ch[dep].time_diff_flag) {

  1111.             int t = ch[dep].time_diff_index;

  1112. 

  1113.             if (ch[dep].time_diff_sign) {

  1114.                 t      = -t;

  1115.                 begin -= t;

  1116.             } else {

  1117.                 end   -= t;

  1118.             }

  1119. 

  1120.             for (smp = begin; smp < end; smp++) {

  1121.                 y  = (1 << 6) +

  1122.                      MUL64(ch[dep].weighting[0], master[smp - 1    ]) +

  1123.                      MUL64(ch[dep].weighting[1], master[smp        ]) +

  1124.                      MUL64(ch[dep].weighting[2], master[smp + 1    ]) +

  1125.                      MUL64(ch[dep].weighting[3], master[smp - 1 + t]) +

  1126.                      MUL64(ch[dep].weighting[4], master[smp     + t]) +

  1127.                      MUL64(ch[dep].weighting[5], master[smp + 1 + t]);

  1128. 

  1129.                 bd->raw_samples[smp] += y >> 7;

  1130.             }

  1131.         } else {

  1132.             for (smp = begin; smp < end; smp++) {

  1133.                 y  = (1 << 6) +

  1134.                      MUL64(ch[dep].weighting[0], master[smp - 1]) +

  1135.                      MUL64(ch[dep].weighting[1], master[smp    ]) +

  1136.                      MUL64(ch[dep].weighting[2], master[smp + 1]);

  1137. 

  1138.                 bd->raw_samples[smp] += y >> 7;

  1139.             }

  1140.         }

  1141. 

  1142.         dep++;

  1143.     }

  1144. 

  1145.     return 0;

  1146. }

  1147. 

  1148. 

  1149. /** Reads the frame data.

  1150.  */

  1151. static int read_frame_data(ALSDecContext *ctx, unsigned int ra_frame)

  1152. {

  1153.     ALSSpecificConfig *sconf = &ctx->sconf;

  1154.     AVCodecContext *avctx    = ctx->avctx;

  1155.     GetBitContext *gb = &ctx->gb;

  1156.     unsigned int div_blocks[32];                ///< block sizes.

  1157.     unsigned int c;

  1158.     unsigned int js_blocks[2];

  1159. 

  1160.     uint32_t bs_info = 0;

  1161. 

  1162.     // skip the size of the ra unit if present in the frame

  1163.     if (sconf->ra_flag == RA_FLAG_FRAMES && ra_frame)

  1164.         skip_bits_long(gb, 32);

  1165. 

  1166.     if (sconf->mc_coding && sconf->joint_stereo) {

  1167.         ctx->js_switch = get_bits1(gb);

  1168.         align_get_bits(gb);

  1169.     }

  1170. 

  1171.     if (!sconf->mc_coding || ctx->js_switch) {

  1172.         int independent_bs = !sconf->joint_stereo;

  1173. 

  1174.         for (c = 0; c < avctx->channels; c++) {

  1175.             js_blocks[0] = 0;

  1176.             js_blocks[1] = 0;

  1177. 

  1178.             get_block_sizes(ctx, div_blocks, &bs_info);

  1179. 

  1180.             // if joint_stereo and block_switching is set, independent decoding

  1181.             // is signaled via the first bit of bs_info

  1182.             if (sconf->joint_stereo && sconf->block_switching)

  1183.                 if (bs_info >> 31)

  1184.                     independent_bs = 2;

  1185. 

  1186.             // if this is the last channel, it has to be decoded independently

  1187.             if (c == avctx->channels - 1)

  1188.                 independent_bs = 1;

  1189. 

  1190.             if (independent_bs) {

  1191.                 if (decode_blocks_ind(ctx, ra_frame, c, div_blocks, js_blocks))

  1192.                     return -1;

  1193. 

  1194.                 independent_bs--;

  1195.             } else {

  1196.                 if (decode_blocks(ctx, ra_frame, c, div_blocks, js_blocks))

  1197.                     return -1;

  1198. 

  1199.                 c++;

  1200.             }

  1201. 

  1202.             // store carryover raw samples

  1203.             memmove(ctx->raw_samples[c] - sconf->max_order,

  1204.                     ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1205.                     sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1206.         }

  1207.     } else { // multi-channel coding

  1208.         ALSBlockData   bd;

  1209.         int            b;

  1210.         int            *reverted_channels = ctx->reverted_channels;

  1211.         unsigned int   offset             = 0;

  1212. 

  1213.         for (c = 0; c < avctx->channels; c++)

  1214.             if (ctx->chan_data[c] < ctx->chan_data_buffer) {

  1215.                 av_log(ctx->avctx, AV_LOG_ERROR, "Invalid channel data!\n");

  1216.                 return -1;

  1217.             }

  1218. 

  1219.         memset(&bd,               0, sizeof(ALSBlockData));

  1220.         memset(reverted_channels, 0, sizeof(*reverted_channels) * avctx->channels);

  1221. 

  1222.         bd.ra_block         = ra_frame;

  1223.         bd.prev_raw_samples = ctx->prev_raw_samples;

  1224. 

  1225.         get_block_sizes(ctx, div_blocks, &bs_info);

  1226. 

  1227.         for (b = 0; b < ctx->num_blocks; b++) {

  1228.             bd.shift_lsbs   = 0;

  1229.             bd.block_length = div_blocks[b];

  1230. 

  1231.             for (c = 0; c < avctx->channels; c++) {

  1232.                 bd.use_ltp     = ctx->use_ltp + c;

  1233.                 bd.ltp_lag     = ctx->ltp_lag + c;

  1234.                 bd.ltp_gain    = ctx->ltp_gain[c];

  1235.                 bd.lpc_cof     = ctx->lpc_cof[c];

  1236.                 bd.quant_cof   = ctx->quant_cof[c];

  1237.                 bd.raw_samples = ctx->raw_samples[c] + offset;

  1238.                 bd.raw_other   = NULL;

  1239. 

  1240.                 read_block(ctx, &bd);

  1241.                 if (read_channel_data(ctx, ctx->chan_data[c], c))

  1242.                     return -1;

  1243.             }

  1244. 

  1245.             for (c = 0; c < avctx->channels; c++)

  1246.                 if (revert_channel_correlation(ctx, &bd, ctx->chan_data,

  1247.                                                reverted_channels, offset, c))

  1248.                     return -1;

  1249. 

  1250.             for (c = 0; c < avctx->channels; c++) {

  1251.                 bd.use_ltp     = ctx->use_ltp + c;

  1252.                 bd.ltp_lag     = ctx->ltp_lag + c;

  1253.                 bd.ltp_gain    = ctx->ltp_gain[c];

  1254.                 bd.lpc_cof     = ctx->lpc_cof[c];

  1255.                 bd.quant_cof   = ctx->quant_cof[c];

  1256.                 bd.raw_samples = ctx->raw_samples[c] + offset;

  1257.                 decode_block(ctx, &bd);

  1258.             }

  1259. 

  1260.             memset(reverted_channels, 0, avctx->channels * sizeof(*reverted_channels));

  1261.             offset      += div_blocks[b];

  1262.             bd.ra_block  = 0;

  1263.         }

  1264. 

  1265.         // store carryover raw samples

  1266.         for (c = 0; c < avctx->channels; c++)

  1267.             memmove(ctx->raw_samples[c] - sconf->max_order,

  1268.                     ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1269.                     sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1270.     }

  1271. 

  1272.     // TODO: read_diff_float_data

  1273. 

  1274.     return 0;

  1275. }

  1276. 

  1277. 

  1278. /** Decodes an ALS frame.

  1279.  */

  1280. static int decode_frame(AVCodecContext *avctx,

  1281.                         void *data, int *data_size,

  1282.                         AVPacket *avpkt)

  1283. {

  1284.     ALSDecContext *ctx       = avctx->priv_data;

  1285.     ALSSpecificConfig *sconf = &ctx->sconf;

  1286.     const uint8_t *buffer    = avpkt->data;

  1287.     int buffer_size          = avpkt->size;

  1288.     int invalid_frame, size;

  1289.     unsigned int c, sample, ra_frame, bytes_read, shift;

  1290. 

  1291.     init_get_bits(&ctx->gb, buffer, buffer_size * 8);

  1292. 

  1293.     // In the case that the distance between random access frames is set to zero

  1294.     // (sconf->ra_distance == 0) no frame is treated as a random access frame.

  1295.     // For the first frame, if prediction is used, all samples used from the

  1296.     // previous frame are assumed to be zero.

  1297.     ra_frame = sconf->ra_distance && !(ctx->frame_id % sconf->ra_distance);

  1298. 

  1299.     // the last frame to decode might have a different length

  1300.     if (sconf->samples != 0xFFFFFFFF)

  1301.         ctx->cur_frame_length = FFMIN(sconf->samples - ctx->frame_id * (uint64_t) sconf->frame_length,

  1302.                                       sconf->frame_length);

  1303.     else

  1304.         ctx->cur_frame_length = sconf->frame_length;

  1305. 

  1306.     // decode the frame data

  1307.     if ((invalid_frame = read_frame_data(ctx, ra_frame) < 0))

  1308.         av_log(ctx->avctx, AV_LOG_WARNING,

  1309.                "Reading frame data failed. Skipping RA unit.\n");

  1310. 

  1311.     ctx->frame_id++;

  1312. 

  1313.     // check for size of decoded data

  1314.     size = ctx->cur_frame_length * avctx->channels *

  1315.            (av_get_bits_per_sample_format(avctx->sample_fmt) >> 3);

  1316. 

  1317.     if (size > *data_size) {

  1318.         av_log(avctx, AV_LOG_ERROR, "Decoded data exceeds buffer size.\n");

  1319.         return -1;

  1320.     }

  1321. 

  1322.     *data_size = size;

  1323. 

  1324.     // transform decoded frame into output format

  1325.     #define INTERLEAVE_OUTPUT(bps)                                 \

  1326.     {                                                              \

  1327.         int##bps##_t *dest = (int##bps##_t*) data;                 \

  1328.         shift = bps - ctx->avctx->bits_per_raw_sample;             \

  1329.         for (sample = 0; sample < ctx->cur_frame_length; sample++) \

  1330.             for (c = 0; c < avctx->channels; c++)                  \

  1331.                 *dest++ = ctx->raw_samples[c][sample] << shift;    \

  1332.     }

  1333. 

  1334.     if (ctx->avctx->bits_per_raw_sample <= 16) {

  1335.         INTERLEAVE_OUTPUT(16)

  1336.     } else {

  1337.         INTERLEAVE_OUTPUT(32)

  1338.     }

  1339. 

  1340.     bytes_read = invalid_frame ? buffer_size :

  1341.                                  (get_bits_count(&ctx->gb) + 7) >> 3;

  1342. 

  1343.     return bytes_read;

  1344. }

  1345. 

  1346. 

  1347. /** Uninitializes the ALS decoder.

  1348.  */

  1349. static av_cold int decode_end(AVCodecContext *avctx)

  1350. {

  1351.     ALSDecContext *ctx = avctx->priv_data;

  1352. 

  1353.     av_freep(&ctx->sconf.chan_pos);

  1354. 

  1355.     av_freep(&ctx->use_ltp);

  1356.     av_freep(&ctx->ltp_lag);

  1357.     av_freep(&ctx->ltp_gain);

  1358.     av_freep(&ctx->ltp_gain_buffer);

  1359.     av_freep(&ctx->quant_cof);

  1360.     av_freep(&ctx->lpc_cof);

  1361.     av_freep(&ctx->quant_cof_buffer);

  1362.     av_freep(&ctx->lpc_cof_buffer);

  1363.     av_freep(&ctx->lpc_cof_reversed_buffer);

  1364.     av_freep(&ctx->prev_raw_samples);

  1365.     av_freep(&ctx->raw_samples);

  1366.     av_freep(&ctx->raw_buffer);

  1367.     av_freep(&ctx->chan_data);

  1368.     av_freep(&ctx->chan_data_buffer);

  1369.     av_freep(&ctx->reverted_channels);

  1370. 

  1371.     return 0;

  1372. }

  1373. 

  1374. 

  1375. /** Initializes the ALS decoder.

  1376.  */

  1377. static av_cold int decode_init(AVCodecContext *avctx)

  1378. {

  1379.     unsigned int c;

  1380.     unsigned int channel_size;

  1381.     int num_buffers;

  1382.     ALSDecContext *ctx = avctx->priv_data;

  1383.     ALSSpecificConfig *sconf = &ctx->sconf;

  1384.     ctx->avctx = avctx;

  1385. 

  1386.     if (!avctx->extradata) {

  1387.         av_log(avctx, AV_LOG_ERROR, "Missing required ALS extradata.\n");

  1388.         return -1;

  1389.     }

  1390. 

  1391.     if (read_specific_config(ctx)) {

  1392.         av_log(avctx, AV_LOG_ERROR, "Reading ALSSpecificConfig failed.\n");

  1393.         decode_end(avctx);

  1394.         return -1;

  1395.     }

  1396. 

  1397.     if (check_specific_config(ctx)) {

  1398.         decode_end(avctx);

  1399.         return -1;

  1400.     }

  1401. 

  1402.     if (sconf->floating) {

  1403.         avctx->sample_fmt          = SAMPLE_FMT_FLT;

  1404.         avctx->bits_per_raw_sample = 32;

  1405.     } else {

  1406.         avctx->sample_fmt          = sconf->resolution > 1

  1407.                                      ? SAMPLE_FMT_S32 : SAMPLE_FMT_S16;

  1408.         avctx->bits_per_raw_sample = (sconf->resolution + 1) * 8;

  1409.     }

  1410. 

  1411.     // set lag value for long-term prediction

  1412.     ctx->ltp_lag_length = 8 + (avctx->sample_rate >=  96000) +

  1413.                               (avctx->sample_rate >= 192000);

  1414. 

  1415.     // allocate quantized parcor coefficient buffer

  1416.     num_buffers = sconf->mc_coding ? avctx->channels : 1;

  1417. 

  1418.     ctx->quant_cof        = av_malloc(sizeof(*ctx->quant_cof) * num_buffers);

  1419.     ctx->lpc_cof          = av_malloc(sizeof(*ctx->lpc_cof)   * num_buffers);

  1420.     ctx->quant_cof_buffer = av_malloc(sizeof(*ctx->quant_cof_buffer) *

  1421.                                       num_buffers * sconf->max_order);

  1422.     ctx->lpc_cof_buffer   = av_malloc(sizeof(*ctx->lpc_cof_buffer) *

  1423.                                       num_buffers * sconf->max_order);

  1424.     ctx->lpc_cof_reversed_buffer = av_malloc(sizeof(*ctx->lpc_cof_buffer) *

  1425.                                              sconf->max_order);

  1426. 

  1427.     if (!ctx->quant_cof              || !ctx->lpc_cof        ||

  1428.         !ctx->quant_cof_buffer       || !ctx->lpc_cof_buffer ||

  1429.         !ctx->lpc_cof_reversed_buffer) {

  1430.         av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1431.         return AVERROR(ENOMEM);

  1432.     }

  1433. 

  1434.     // assign quantized parcor coefficient buffers

  1435.     for (c = 0; c < num_buffers; c++) {

  1436.         ctx->quant_cof[c] = ctx->quant_cof_buffer + c * sconf->max_order;

  1437.         ctx->lpc_cof[c]   = ctx->lpc_cof_buffer   + c * sconf->max_order;

  1438.     }

  1439. 

  1440.     // allocate and assign lag and gain data buffer for ltp mode

  1441.     ctx->use_ltp         = av_mallocz(sizeof(*ctx->use_ltp)  * num_buffers);

  1442.     ctx->ltp_lag         = av_malloc (sizeof(*ctx->ltp_lag)  * num_buffers);

  1443.     ctx->ltp_gain        = av_malloc (sizeof(*ctx->ltp_gain) * num_buffers);

  1444.     ctx->ltp_gain_buffer = av_malloc (sizeof(*ctx->ltp_gain_buffer) *

  1445.                                       num_buffers * 5);

  1446. 

  1447.     if (!ctx->use_ltp  || !ctx->ltp_lag ||

  1448.         !ctx->ltp_gain || !ctx->ltp_gain_buffer) {

  1449.         av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1450.         decode_end(avctx);

  1451.         return AVERROR(ENOMEM);

  1452.     }

  1453. 

  1454.     for (c = 0; c < num_buffers; c++)

  1455.         ctx->ltp_gain[c] = ctx->ltp_gain_buffer + c * 5;

  1456. 

  1457.     // allocate and assign channel data buffer for mcc mode

  1458.     if (sconf->mc_coding) {

  1459.         ctx->chan_data_buffer  = av_malloc(sizeof(*ctx->chan_data_buffer) *

  1460.                                            num_buffers);

  1461.         ctx->chan_data         = av_malloc(sizeof(ALSChannelData) *

  1462.                                            num_buffers);

  1463.         ctx->reverted_channels = av_malloc(sizeof(*ctx->reverted_channels) *

  1464.                                            num_buffers);

  1465. 

  1466.         if (!ctx->chan_data_buffer || !ctx->chan_data || !ctx->reverted_channels) {

  1467.             av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1468.             decode_end(avctx);

  1469.             return AVERROR(ENOMEM);

  1470.         }

  1471. 

  1472.         for (c = 0; c < num_buffers; c++)

  1473.             ctx->chan_data[c] = ctx->chan_data_buffer + c;

  1474.     } else {

  1475.         ctx->chan_data         = NULL;

  1476.         ctx->chan_data_buffer  = NULL;

  1477.         ctx->reverted_channels = NULL;

  1478.     }

  1479. 

  1480.     avctx->frame_size = sconf->frame_length;

  1481.     channel_size      = sconf->frame_length + sconf->max_order;

  1482. 

  1483.     ctx->prev_raw_samples = av_malloc (sizeof(*ctx->prev_raw_samples) * sconf->max_order);

  1484.     ctx->raw_buffer       = av_mallocz(sizeof(*ctx->     raw_buffer)  * avctx->channels * channel_size);

  1485.     ctx->raw_samples      = av_malloc (sizeof(*ctx->     raw_samples) * avctx->channels);

  1486. 

  1487.     // allocate previous raw sample buffer

  1488.     if (!ctx->prev_raw_samples || !ctx->raw_buffer|| !ctx->raw_samples) {

  1489.         av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1490.         decode_end(avctx);

  1491.         return AVERROR(ENOMEM);

  1492.     }

  1493. 

  1494.     // assign raw samples buffers

  1495.     ctx->raw_samples[0] = ctx->raw_buffer + sconf->max_order;

  1496.     for (c = 1; c < avctx->channels; c++)

  1497.         ctx->raw_samples[c] = ctx->raw_samples[c - 1] + channel_size;

  1498. 

  1499.     return 0;

  1500. }

  1501. 

  1502. 

  1503. /** Flushes (resets) the frame ID after seeking.

  1504.  */

  1505. static av_cold void flush(AVCodecContext *avctx)

  1506. {

  1507.     ALSDecContext *ctx = avctx->priv_data;

  1508. 

  1509.     ctx->frame_id = 0;

  1510. }

  1511. 

  1512. 

  1513. AVCodec als_decoder = {

  1514.     "als",

  1515.     CODEC_TYPE_AUDIO,

  1516.     CODEC_ID_MP4ALS,

  1517.     sizeof(ALSDecContext),

  1518.     decode_init,

  1519.     NULL,

  1520.     decode_end,

  1521.     decode_frame,

  1522.     .flush = flush,

  1523.     .capabilities = CODEC_CAP_SUBFRAMES,

  1524.     .long_name = NULL_IF_CONFIG_SMALL("MPEG-4 Audio Lossless Coding (ALS)"),

  1525. };