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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_ mail.de>

  4.  *

  5.  * This file is part of FFmpeg.

  6.  *

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

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

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

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

  11.  *

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

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

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

  15.  * Lesser General Public License for more details.

  16.  *

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

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

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

  20.  */

  21. 

  22. /**

  23.  * @file

  24.  * MPEG-4 ALS decoder

  25.  * @author Thilo Borgmann <thilo.borgmann _at_ mail.de>

  26.  */

  27. 

  28. #include <inttypes.h>

  29. 

  30. #include "avcodec.h"

  31. #include "get_bits.h"

  32. #include "unary.h"

  33. #include "mpeg4audio.h"

  34. #include "bytestream.h"

  35. #include "bgmc.h"

  36. #include "dsputil.h"

  37. #include "internal.h"

  38. #include "libavutil/samplefmt.h"

  39. #include "libavutil/crc.h"

  40. 

  41. #include <stdint.h>

  42. 

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

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

  45.  *  by the encoder and stored in ALSSpecificConfig.

  46.  */

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

  48.     { {-52, 4}, {-29, 5}, {-31, 4}, { 19, 4}, {-16, 4},

  49.       { 12, 3}, { -7, 3}, {  9, 3}, { -5, 3}, {  6, 3},

  50.       { -4, 3}, {  3, 3}, { -3, 2}, {  3, 2}, { -2, 2},

  51.       {  3, 2}, { -1, 2}, {  2, 2}, { -1, 2}, {  2, 2} },

  52.     { {-58, 3}, {-42, 4}, {-46, 4}, { 37, 5}, {-36, 4},

  53.       { 29, 4}, {-29, 4}, { 25, 4}, {-23, 4}, { 20, 4},

  54.       {-17, 4}, { 16, 4}, {-12, 4}, { 12, 3}, {-10, 4},

  55.       {  7, 3}, { -4, 4}, {  3, 3}, { -1, 3}, {  1, 3} },

  56.     { {-59, 3}, {-45, 5}, {-50, 4}, { 38, 4}, {-39, 4},

  57.       { 32, 4}, {-30, 4}, { 25, 3}, {-23, 3}, { 20, 3},

  58.       {-20, 3}, { 16, 3}, {-13, 3}, { 10, 3}, { -7, 3},

  59.       {  3, 3}, {  0, 3}, { -1, 3}, {  2, 3}, { -1, 2} }

  60. };

  61. 

  62. 

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

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

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

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

  67.  */

  68. static const int16_t parcor_scaled_values[] = {

  69.     -1048544 / 32, -1048288 / 32, -1047776 / 32, -1047008 / 32,

  70.     -1045984 / 32, -1044704 / 32, -1043168 / 32, -1041376 / 32,

  71.     -1039328 / 32, -1037024 / 32, -1034464 / 32, -1031648 / 32,

  72.     -1028576 / 32, -1025248 / 32, -1021664 / 32, -1017824 / 32,

  73.     -1013728 / 32, -1009376 / 32, -1004768 / 32,  -999904 / 32,

  74.      -994784 / 32,  -989408 / 32,  -983776 / 32,  -977888 / 32,

  75.      -971744 / 32,  -965344 / 32,  -958688 / 32,  -951776 / 32,

  76.      -944608 / 32,  -937184 / 32,  -929504 / 32,  -921568 / 32,

  77.      -913376 / 32,  -904928 / 32,  -896224 / 32,  -887264 / 32,

  78.      -878048 / 32,  -868576 / 32,  -858848 / 32,  -848864 / 32,

  79.      -838624 / 32,  -828128 / 32,  -817376 / 32,  -806368 / 32,

  80.      -795104 / 32,  -783584 / 32,  -771808 / 32,  -759776 / 32,

  81.      -747488 / 32,  -734944 / 32,  -722144 / 32,  -709088 / 32,

  82.      -695776 / 32,  -682208 / 32,  -668384 / 32,  -654304 / 32,

  83.      -639968 / 32,  -625376 / 32,  -610528 / 32,  -595424 / 32,

  84.      -580064 / 32,  -564448 / 32,  -548576 / 32,  -532448 / 32,

  85.      -516064 / 32,  -499424 / 32,  -482528 / 32,  -465376 / 32,

  86.      -447968 / 32,  -430304 / 32,  -412384 / 32,  -394208 / 32,

  87.      -375776 / 32,  -357088 / 32,  -338144 / 32,  -318944 / 32,

  88.      -299488 / 32,  -279776 / 32,  -259808 / 32,  -239584 / 32,

  89.      -219104 / 32,  -198368 / 32,  -177376 / 32,  -156128 / 32,

  90.      -134624 / 32,  -112864 / 32,   -90848 / 32,   -68576 / 32,

  91.       -46048 / 32,   -23264 / 32,     -224 / 32,    23072 / 32,

  92.        46624 / 32,    70432 / 32,    94496 / 32,   118816 / 32,

  93.       143392 / 32,   168224 / 32,   193312 / 32,   218656 / 32,

  94.       244256 / 32,   270112 / 32,   296224 / 32,   322592 / 32,

  95.       349216 / 32,   376096 / 32,   403232 / 32,   430624 / 32,

  96.       458272 / 32,   486176 / 32,   514336 / 32,   542752 / 32,

  97.       571424 / 32,   600352 / 32,   629536 / 32,   658976 / 32,

  98.       688672 / 32,   718624 / 32,   748832 / 32,   779296 / 32,

  99.       810016 / 32,   840992 / 32,   872224 / 32,   903712 / 32,

  100.       935456 / 32,   967456 / 32,   999712 / 32,  1032224 / 32

  101. };

  102. 

  103. 

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

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

  106.  */

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

  108.     { 0,  8, 16,  24},

  109.     {32, 40, 48,  56},

  110.     {64, 70, 76,  82},

  111.     {88, 92, 96, 100}

  112. };

  113. 

  114. 

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

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

  117.  */

  118. static const int16_t mcc_weightings[] = {

  119.     204,  192,  179,  166,  153,  140,  128,  115,

  120.     102,   89,   76,   64,   51,   38,   25,   12,

  121.       0,  -12,  -25,  -38,  -51,  -64,  -76,  -89,

  122.    -102, -115, -128, -140, -153, -166, -179, -192

  123. };

  124. 

  125. 

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

  127.  */

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

  129.     { 74, 44, 25, 13,  7, 3},

  130.     { 68, 42, 24, 13,  7, 3},

  131.     { 58, 39, 23, 13,  7, 3},

  132.     {126, 70, 37, 19, 10, 5},

  133.     {132, 70, 37, 20, 10, 5},

  134.     {124, 70, 38, 20, 10, 5},

  135.     {120, 69, 37, 20, 11, 5},

  136.     {116, 67, 37, 20, 11, 5},

  137.     {108, 66, 36, 20, 10, 5},

  138.     {102, 62, 36, 20, 10, 5},

  139.     { 88, 58, 34, 19, 10, 5},

  140.     {162, 89, 49, 25, 13, 7},

  141.     {156, 87, 49, 26, 14, 7},

  142.     {150, 86, 47, 26, 14, 7},

  143.     {142, 84, 47, 26, 14, 7},

  144.     {131, 79, 46, 26, 14, 7}

  145. };

  146. 

  147. 

  148. enum RA_Flag {

  149.     RA_FLAG_NONE,

  150.     RA_FLAG_FRAMES,

  151.     RA_FLAG_HEADER

  152. };

  153. 

  154. 

  155. typedef struct {

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  178. } ALSSpecificConfig;

  179. 

  180. 

  181. typedef struct {

  182.     int stop_flag;

  183.     int master_channel;

  184.     int time_diff_flag;

  185.     int time_diff_sign;

  186.     int time_diff_index;

  187.     int weighting[6];

  188. } ALSChannelData;

  189. 

  190. 

  191. typedef struct {

  192.     AVCodecContext *avctx;

  193.     ALSSpecificConfig sconf;

  194.     GetBitContext gb;

  195.     DSPContext dsp;

  196.     const AVCRC *crc_table;

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

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

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

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

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

  202.     unsigned int cs_switch;         ///< if true, channel rearrangement is done

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  228. } ALSDecContext;

  229. 

  230. 

  231. typedef struct {

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  247. } ALSBlockData;

  248. 

  249. 

  250. static av_cold void dprint_specific_config(ALSDecContext *ctx)

  251. {

  252. #ifdef DEBUG

  253.     AVCodecContext *avctx    = ctx->avctx;

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

  255. 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  274. #endif

  275. }

  276. 

  277. 

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

  279.  */

  280. static av_cold int read_specific_config(ALSDecContext *ctx)

  281. {

  282.     GetBitContext gb;

  283.     uint64_t ht_size;

  284.     int i, config_offset;

  285.     MPEG4AudioConfig m4ac;

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

  287.     AVCodecContext *avctx    = ctx->avctx;

  288.     uint32_t als_id, header_size, trailer_size;

  289.     int ret;

  290. 

  291.     if ((ret = init_get_bits8(&gb, avctx->extradata, avctx->extradata_size)) < 0)

  292.         return ret;

  293. 

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

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

  296. 

  297.     if (config_offset < 0)

  298.         return AVERROR_INVALIDDATA;

  299. 

  300.     skip_bits_long(&gb, config_offset);

  301. 

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

  303.         return AVERROR_INVALIDDATA;

  304. 

  305.     // read the fixed items

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

  307.     avctx->sample_rate          = m4ac.sample_rate;

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

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

  310.     avctx->channels             = m4ac.channels;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  334. 

  335. 

  336.     // check for ALSSpecificConfig struct

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

  338.         return AVERROR_INVALIDDATA;

  339. 

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

  341. 

  342.     // read channel config

  343.     if (sconf->chan_config)

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

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

  346. 

  347. 

  348.     // read channel sorting

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

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

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

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

  353.             return AVERROR_INVALIDDATA;

  354. 

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

  356.             return AVERROR(ENOMEM);

  357. 

  358.         ctx->cs_switch = 1;

  359. 

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

  361.             int idx;

  362. 

  363.             idx = get_bits(&gb, chan_pos_bits);

  364.             if (idx >= avctx->channels) {

  365.                 av_log(avctx, AV_LOG_WARNING, "Invalid channel reordering.\n");

  366.                 ctx->cs_switch = 0;

  367.                 break;

  368.             }

  369.             sconf->chan_pos[idx] = i;

  370.         }

  371. 

  372.         align_get_bits(&gb);

  373.     }

  374. 

  375. 

  376.     // read fixed header and trailer sizes,

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

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

  379.         return AVERROR_INVALIDDATA;

  380. 

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

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

  383.     if (header_size  == 0xFFFFFFFF)

  384.         header_size  = 0;

  385.     if (trailer_size == 0xFFFFFFFF)

  386.         trailer_size = 0;

  387. 

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

  389. 

  390. 

  391.     // skip the header and trailer data

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

  393.         return AVERROR_INVALIDDATA;

  394. 

  395.     if (ht_size > INT32_MAX)

  396.         return AVERROR_PATCHWELCOME;

  397. 

  398.     skip_bits_long(&gb, ht_size);

  399. 

  400. 

  401.     // initialize CRC calculation

  402.     if (sconf->crc_enabled) {

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

  404.             return AVERROR_INVALIDDATA;

  405. 

  406.         if (avctx->err_recognition & (AV_EF_CRCCHECK|AV_EF_CAREFUL)) {

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

  408.             ctx->crc       = 0xFFFFFFFF;

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

  410.         } else

  411.             skip_bits_long(&gb, 32);

  412.     }

  413. 

  414. 

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

  416. 

  417.     dprint_specific_config(ctx);

  418. 

  419.     return 0;

  420. }

  421. 

  422. 

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

  424.  */

  425. static int check_specific_config(ALSDecContext *ctx)

  426. {

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

  428.     int error = 0;

  429. 

  430.     // report unsupported feature and set error value

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

  432.     {                                                   \

  433.         if (cond) {                                     \

  434.             avpriv_report_missing_feature(ctx->avctx,   \

  435.                                           str);         \

  436.             error = errval;                             \

  437.         }                                               \

  438.     }

  439. 

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

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

  442. 

  443.     return error;

  444. }

  445. 

  446. 

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

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

  449.  */

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

  451.                           unsigned int div, unsigned int **div_blocks,

  452.                           unsigned int *num_blocks)

  453. {

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

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

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

  457.         n   *= 2;

  458.         div += 1;

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

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

  461.     } else {

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

  463.         // (bit implicitly not set)

  464.         **div_blocks = div;

  465.         (*div_blocks)++;

  466.         (*num_blocks)++;

  467.     }

  468. }

  469. 

  470. 

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

  472.  */

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

  474. {

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

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

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

  478. 

  479.     if (k > 1) {

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

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

  482.     } else if (!k) {

  483.         q >>= 1;

  484.     }

  485.     return r ? q : ~q;

  486. }

  487. 

  488. 

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

  490.  */

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

  492. {

  493.     int i, j;

  494. 

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

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

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

  498.         cof[i]  += tmp1;

  499.     }

  500.     if (i == j)

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

  502. 

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

  504. }

  505. 

  506. 

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

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

  509.  *  actual number of samples.

  510.  */

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

  512.                             uint32_t *bs_info)

  513. {

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

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

  516.     unsigned int *ptr_div_blocks = div_blocks;

  517.     unsigned int b;

  518. 

  519.     if (sconf->block_switching) {

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

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

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

  523.     }

  524. 

  525.     ctx->num_blocks = 0;

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

  527. 

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

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

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

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

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

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

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

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

  536.     // codec RM22 revision 2.

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

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

  539.     // of 14496-3.

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

  541.     // frame.

  542. 

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

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

  545. 

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

  547.         unsigned int remaining = ctx->cur_frame_length;

  548. 

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

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

  551.                 div_blocks[b] = remaining;

  552.                 ctx->num_blocks = b + 1;

  553.                 break;

  554.             }

  555. 

  556.             remaining -= div_blocks[b];

  557.         }

  558.     }

  559. }

  560. 

  561. 

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

  563.  */

  564. static int read_const_block_data(ALSDecContext *ctx, ALSBlockData *bd)

  565. {

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

  567.     AVCodecContext *avctx    = ctx->avctx;

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

  569. 

  570.     if (bd->block_length <= 0)

  571.         return AVERROR_INVALIDDATA;

  572. 

  573.     *bd->raw_samples = 0;

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

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

  576. 

  577.     // skip 5 reserved bits

  578.     skip_bits(gb, 5);

  579. 

  580.     if (*bd->const_block) {

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

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

  583.     }

  584. 

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

  586.     *bd->const_block = 1;

  587. 

  588.     return 0;

  589. }

  590. 

  591. 

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

  593.  */

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

  595. {

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

  597.     int32_t  val = *bd->raw_samples;

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

  599. 

  600.     // write raw samples into buffer

  601.     for (; smp; smp--)

  602.         *dst++ = val;

  603. }

  604. 

  605. 

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

  607.  */

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

  609. {

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

  611.     AVCodecContext *avctx    = ctx->avctx;

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

  613.     unsigned int k;

  614.     unsigned int s[8];

  615.     unsigned int sx[8];

  616.     unsigned int sub_blocks, log2_sub_blocks, sb_length;

  617.     unsigned int start      = 0;

  618.     unsigned int opt_order;

  619.     int          sb;

  620.     int32_t      *quant_cof = bd->quant_cof;

  621.     int32_t      *current_res;

  622. 

  623. 

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

  625.     *bd->const_block = 0;

  626. 

  627.     *bd->opt_order  = 1;

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

  629. 

  630.     opt_order       = *bd->opt_order;

  631. 

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

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

  634.         log2_sub_blocks = 0;

  635.     } else {

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

  637.             log2_sub_blocks = get_bits(gb, 2);

  638.         else

  639.             log2_sub_blocks = 2 * get_bits1(gb);

  640.     }

  641. 

  642.     sub_blocks = 1 << log2_sub_blocks;

  643. 

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

  645.     // block_length must be evenly divisible by sub_blocks

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

  647.         av_log(avctx, AV_LOG_WARNING,

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

  649.         return AVERROR_INVALIDDATA;

  650.     }

  651. 

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

  653. 

  654.     if (sconf->bgmc) {

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

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

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

  658. 

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

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

  661.             s [k] >>= 4;

  662.         }

  663.     } else {

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

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

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

  667.     }

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

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

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

  671.             return AVERROR_INVALIDDATA;

  672.         }

  673. 

  674.     if (get_bits1(gb))

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

  676. 

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

  678. 

  679. 

  680.     if (!sconf->rlslms) {

  681.         if (sconf->adapt_order) {

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

  683.                                                 2, sconf->max_order + 1));

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

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

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

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

  688.                 return AVERROR_INVALIDDATA;

  689.             }

  690.         } else {

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

  692.         }

  693.         if (*bd->opt_order > bd->block_length) {

  694.             *bd->opt_order = bd->block_length;

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

  696.             return AVERROR_INVALIDDATA;

  697.         }

  698.         opt_order = *bd->opt_order;

  699. 

  700.         if (opt_order) {

  701.             int add_base;

  702. 

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

  704.                 add_base = 0x7F;

  705. 

  706.                 // read coefficient 0

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

  708. 

  709.                 // read coefficient 1

  710.                 if (opt_order > 1)

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

  712. 

  713.                 // read coefficients 2 to opt_order

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

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

  716.             } else {

  717.                 int k_max;

  718.                 add_base = 1;

  719. 

  720.                 // read coefficient 0 to 19

  721.                 k_max = FFMIN(opt_order, 20);

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

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

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

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

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

  727.                         av_log(avctx, AV_LOG_ERROR,

  728.                                "quant_cof %"PRIu32" is out of range.\n",

  729.                                quant_cof[k]);

  730.                         return AVERROR_INVALIDDATA;

  731.                     }

  732.                 }

  733. 

  734.                 // read coefficients 20 to 126

  735.                 k_max = FFMIN(opt_order, 127);

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

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

  738. 

  739.                 // read coefficients 127 to opt_order

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

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

  742. 

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

  744. 

  745.                 if (opt_order > 1)

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

  747.             }

  748. 

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

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

  751.         }

  752.     }

  753. 

  754.     // read LTP gain and lag values

  755.     if (sconf->long_term_prediction) {

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

  757. 

  758.         if (*bd->use_ltp) {

  759.             int r, c;

  760. 

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

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

  763. 

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

  765.             c                 = get_bits(gb, 2);

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

  767. 

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

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

  770. 

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

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

  773.         }

  774.     }

  775. 

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

  777.     if (bd->ra_block) {

  778.         if (opt_order)

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

  780.         if (opt_order > 1)

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

  782.         if (opt_order > 2)

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

  784. 

  785.         start = FFMIN(opt_order, 3);

  786.     }

  787. 

  788.     // read all residuals

  789.     if (sconf->bgmc) {

  790.         int          delta[8];

  791.         unsigned int k    [8];

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

  793. 

  794.         // read most significant bits

  795.         unsigned int high;

  796.         unsigned int low;

  797.         unsigned int value;

  798. 

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

  800. 

  801.         current_res = bd->raw_samples + start;

  802. 

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

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

  805. 

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

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

  808. 

  809.             ff_bgmc_decode(gb, sb_len, current_res,

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

  811. 

  812.             current_res += sb_len;

  813.         }

  814. 

  815.         ff_bgmc_decode_end(gb);

  816. 

  817. 

  818.         // read least significant bits and tails

  819.         current_res = bd->raw_samples + start;

  820. 

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

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

  823.             unsigned int cur_k         = k[sb];

  824.             unsigned int cur_s         = s[sb];

  825. 

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

  827.                 int32_t res = *current_res;

  828. 

  829.                 if (res == cur_tail_code) {

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

  831.                                           << (5 - delta[sb]);

  832. 

  833.                     res = decode_rice(gb, cur_s);

  834. 

  835.                     if (res >= 0) {

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

  837.                     } else {

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

  839.                     }

  840.                 } else {

  841.                     if (res > cur_tail_code)

  842.                         res--;

  843. 

  844.                     if (res & 1)

  845.                         res = -res;

  846. 

  847.                     res >>= 1;

  848. 

  849.                     if (cur_k) {

  850.                         res <<= cur_k;

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

  852.                     }

  853.                 }

  854. 

  855.                 *current_res++ = res;

  856.             }

  857.         }

  858.     } else {

  859.         current_res = bd->raw_samples + start;

  860. 

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

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

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

  864.      }

  865. 

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

  867.         align_get_bits(gb);

  868. 

  869.     return 0;

  870. }

  871. 

  872. 

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

  874.  */

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

  876. {

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

  878.     unsigned int block_length = bd->block_length;

  879.     unsigned int smp = 0;

  880.     unsigned int k;

  881.     int opt_order             = *bd->opt_order;

  882.     int sb;

  883.     int64_t y;

  884.     int32_t *quant_cof        = bd->quant_cof;

  885.     int32_t *lpc_cof          = bd->lpc_cof;

  886.     int32_t *raw_samples      = bd->raw_samples;

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

  888.     int32_t *lpc_cof_reversed = ctx->lpc_cof_reversed_buffer;

  889. 

  890.     // reverse long-term prediction

  891.     if (*bd->use_ltp) {

  892.         int ltp_smp;

  893. 

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

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

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

  897.             int end    = center + 3;

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

  899.             int base;

  900. 

  901.             y = 1 << 6;

  902. 

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

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

  905. 

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

  907.         }

  908.     }

  909. 

  910.     // reconstruct all samples from residuals

  911.     if (bd->ra_block) {

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

  913.             y = 1 << 19;

  914. 

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

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

  917. 

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

  919.             parcor_to_lpc(smp, quant_cof, lpc_cof);

  920.         }

  921.     } else {

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

  923.             parcor_to_lpc(k, quant_cof, lpc_cof);

  924. 

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

  926.         if (*bd->store_prev_samples)

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

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

  929. 

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

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

  932.             int32_t *left, *right;

  933. 

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

  935.                 left  = raw_samples;

  936.                 right = bd->raw_other;

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

  938.                 left  = bd->raw_other;

  939.                 right = raw_samples;

  940.             }

  941. 

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

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

  944.         }

  945. 

  946.         // reconstruct shifted signal

  947.         if (*bd->shift_lsbs)

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

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

  950.     }

  951. 

  952.     // reverse linear prediction coefficients for efficiency

  953.     lpc_cof = lpc_cof + opt_order;

  954. 

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

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

  957. 

  958.     // reconstruct raw samples

  959.     raw_samples = bd->raw_samples + smp;

  960.     lpc_cof     = lpc_cof_reversed + opt_order;

  961. 

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

  963.         y = 1 << 19;

  964. 

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

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

  967. 

  968.         *raw_samples -= y >> 20;

  969.     }

  970. 

  971.     raw_samples = bd->raw_samples;

  972. 

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

  974.     if (*bd->store_prev_samples)

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

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

  977. 

  978.     return 0;

  979. }

  980. 

  981. 

  982. /** Read the block data.

  983.  */

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

  985. {

  986.     int ret;

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

  988. 

  989.     *bd->shift_lsbs = 0;

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

  991.     if (get_bits1(gb)) {

  992.         ret = read_var_block_data(ctx, bd);

  993.     } else {

  994.         ret = read_const_block_data(ctx, bd);

  995.     }

  996. 

  997.     return ret;

  998. }

  999. 

  1000. 

  1001. /** Decode the block data.

  1002.  */

  1003. static int decode_block(ALSDecContext *ctx, ALSBlockData *bd)

  1004. {

  1005.     unsigned int smp;

  1006.     int ret = 0;

  1007. 

  1008.     // read block type flag and read the samples accordingly

  1009.     if (*bd->const_block)

  1010.         decode_const_block_data(ctx, bd);

  1011.     else

  1012.         ret = decode_var_block_data(ctx, bd); // always return 0

  1013. 

  1014.     if (ret < 0)

  1015.         return ret;

  1016. 

  1017.     // TODO: read RLSLMS extension data

  1018. 

  1019.     if (*bd->shift_lsbs)

  1020.         for (smp = 0; smp < bd->block_length; smp++)

  1021.             bd->raw_samples[smp] <<= *bd->shift_lsbs;

  1022. 

  1023.     return 0;

  1024. }

  1025. 

  1026. 

  1027. /** Read and decode block data successively.

  1028.  */

  1029. static int read_decode_block(ALSDecContext *ctx, ALSBlockData *bd)

  1030. {

  1031.     int ret;

  1032. 

  1033.     if ((ret = read_block(ctx, bd)) < 0)

  1034.         return ret;

  1035. 

  1036.     return decode_block(ctx, bd);

  1037. }

  1038. 

  1039. 

  1040. /** Compute the number of samples left to decode for the current frame and

  1041.  *  sets these samples to zero.

  1042.  */

  1043. static void zero_remaining(unsigned int b, unsigned int b_max,

  1044.                            const unsigned int *div_blocks, int32_t *buf)

  1045. {

  1046.     unsigned int count = 0;

  1047. 

  1048.     while (b < b_max)

  1049.         count += div_blocks[b++];

  1050. 

  1051.     if (count)

  1052.         memset(buf, 0, sizeof(*buf) * count);

  1053. }

  1054. 

  1055. 

  1056. /** Decode blocks independently.

  1057.  */

  1058. static int decode_blocks_ind(ALSDecContext *ctx, unsigned int ra_frame,

  1059.                              unsigned int c, const unsigned int *div_blocks,

  1060.                              unsigned int *js_blocks)

  1061. {

  1062.     int ret;

  1063.     unsigned int b;

  1064.     ALSBlockData bd = { 0 };

  1065. 

  1066.     bd.ra_block         = ra_frame;

  1067.     bd.const_block      = ctx->const_block;

  1068.     bd.shift_lsbs       = ctx->shift_lsbs;

  1069.     bd.opt_order        = ctx->opt_order;

  1070.     bd.store_prev_samples = ctx->store_prev_samples;

  1071.     bd.use_ltp          = ctx->use_ltp;

  1072.     bd.ltp_lag          = ctx->ltp_lag;

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

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

  1075.     bd.lpc_cof          = ctx->lpc_cof[0];

  1076.     bd.prev_raw_samples = ctx->prev_raw_samples;

  1077.     bd.raw_samples      = ctx->raw_samples[c];

  1078. 

  1079. 

  1080.     for (b = 0; b < ctx->num_blocks; b++) {

  1081.         bd.block_length     = div_blocks[b];

  1082. 

  1083.         if ((ret = read_decode_block(ctx, &bd)) < 0) {

  1084.             // damaged block, write zero for the rest of the frame

  1085.             zero_remaining(b, ctx->num_blocks, div_blocks, bd.raw_samples);

  1086.             return ret;

  1087.         }

  1088.         bd.raw_samples += div_blocks[b];

  1089.         bd.ra_block     = 0;

  1090.     }

  1091. 

  1092.     return 0;

  1093. }

  1094. 

  1095. 

  1096. /** Decode blocks dependently.

  1097.  */

  1098. static int decode_blocks(ALSDecContext *ctx, unsigned int ra_frame,

  1099.                          unsigned int c, const unsigned int *div_blocks,

  1100.                          unsigned int *js_blocks)

  1101. {

  1102.     ALSSpecificConfig *sconf = &ctx->sconf;

  1103.     unsigned int offset = 0;

  1104.     unsigned int b;

  1105.     int ret;

  1106.     ALSBlockData bd[2] = { { 0 } };

  1107. 

  1108.     bd[0].ra_block         = ra_frame;

  1109.     bd[0].const_block      = ctx->const_block;

  1110.     bd[0].shift_lsbs       = ctx->shift_lsbs;

  1111.     bd[0].opt_order        = ctx->opt_order;

  1112.     bd[0].store_prev_samples = ctx->store_prev_samples;

  1113.     bd[0].use_ltp          = ctx->use_ltp;

  1114.     bd[0].ltp_lag          = ctx->ltp_lag;

  1115.     bd[0].ltp_gain         = ctx->ltp_gain[0];

  1116.     bd[0].quant_cof        = ctx->quant_cof[0];

  1117.     bd[0].lpc_cof          = ctx->lpc_cof[0];

  1118.     bd[0].prev_raw_samples = ctx->prev_raw_samples;

  1119.     bd[0].js_blocks        = *js_blocks;

  1120. 

  1121.     bd[1].ra_block         = ra_frame;

  1122.     bd[1].const_block      = ctx->const_block;

  1123.     bd[1].shift_lsbs       = ctx->shift_lsbs;

  1124.     bd[1].opt_order        = ctx->opt_order;

  1125.     bd[1].store_prev_samples = ctx->store_prev_samples;

  1126.     bd[1].use_ltp          = ctx->use_ltp;

  1127.     bd[1].ltp_lag          = ctx->ltp_lag;

  1128.     bd[1].ltp_gain         = ctx->ltp_gain[0];

  1129.     bd[1].quant_cof        = ctx->quant_cof[0];

  1130.     bd[1].lpc_cof          = ctx->lpc_cof[0];

  1131.     bd[1].prev_raw_samples = ctx->prev_raw_samples;

  1132.     bd[1].js_blocks        = *(js_blocks + 1);

  1133. 

  1134.     // decode all blocks

  1135.     for (b = 0; b < ctx->num_blocks; b++) {

  1136.         unsigned int s;

  1137. 

  1138.         bd[0].block_length = div_blocks[b];

  1139.         bd[1].block_length = div_blocks[b];

  1140. 

  1141.         bd[0].raw_samples  = ctx->raw_samples[c    ] + offset;

  1142.         bd[1].raw_samples  = ctx->raw_samples[c + 1] + offset;

  1143. 

  1144.         bd[0].raw_other    = bd[1].raw_samples;

  1145.         bd[1].raw_other    = bd[0].raw_samples;

  1146. 

  1147.         if ((ret = read_decode_block(ctx, &bd[0])) < 0 ||

  1148.             (ret = read_decode_block(ctx, &bd[1])) < 0)

  1149.             goto fail;

  1150. 

  1151.         // reconstruct joint-stereo blocks

  1152.         if (bd[0].js_blocks) {

  1153.             if (bd[1].js_blocks)

  1154.                 av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel pair.\n");

  1155. 

  1156.             for (s = 0; s < div_blocks[b]; s++)

  1157.                 bd[0].raw_samples[s] = bd[1].raw_samples[s] - bd[0].raw_samples[s];

  1158.         } else if (bd[1].js_blocks) {

  1159.             for (s = 0; s < div_blocks[b]; s++)

  1160.                 bd[1].raw_samples[s] = bd[1].raw_samples[s] + bd[0].raw_samples[s];

  1161.         }

  1162. 

  1163.         offset  += div_blocks[b];

  1164.         bd[0].ra_block = 0;

  1165.         bd[1].ra_block = 0;

  1166.     }

  1167. 

  1168.     // store carryover raw samples,

  1169.     // the others channel raw samples are stored by the calling function.

  1170.     memmove(ctx->raw_samples[c] - sconf->max_order,

  1171.             ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1172.             sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1173. 

  1174.     return 0;

  1175. fail:

  1176.     // damaged block, write zero for the rest of the frame

  1177.     zero_remaining(b, ctx->num_blocks, div_blocks, bd[0].raw_samples);

  1178.     zero_remaining(b, ctx->num_blocks, div_blocks, bd[1].raw_samples);

  1179.     return ret;

  1180. }

  1181. 

  1182. static inline int als_weighting(GetBitContext *gb, int k, int off)

  1183. {

  1184.     int idx = av_clip(decode_rice(gb, k) + off,

  1185.                       0, FF_ARRAY_ELEMS(mcc_weightings) - 1);

  1186.     return mcc_weightings[idx];

  1187. }

  1188. 

  1189. /** Read the channel data.

  1190.   */

  1191. static int read_channel_data(ALSDecContext *ctx, ALSChannelData *cd, int c)

  1192. {

  1193.     GetBitContext *gb       = &ctx->gb;

  1194.     ALSChannelData *current = cd;

  1195.     unsigned int channels   = ctx->avctx->channels;

  1196.     int entries             = 0;

  1197. 

  1198.     while (entries < channels && !(current->stop_flag = get_bits1(gb))) {

  1199.         current->master_channel = get_bits_long(gb, av_ceil_log2(channels));

  1200. 

  1201.         if (current->master_channel >= channels) {

  1202.             av_log(ctx->avctx, AV_LOG_ERROR, "Invalid master channel.\n");

  1203.             return AVERROR_INVALIDDATA;

  1204.         }

  1205. 

  1206.         if (current->master_channel != c) {

  1207.             current->time_diff_flag = get_bits1(gb);

  1208.             current->weighting[0]   = als_weighting(gb, 1, 16);

  1209.             current->weighting[1]   = als_weighting(gb, 2, 14);

  1210.             current->weighting[2]   = als_weighting(gb, 1, 16);

  1211. 

  1212.             if (current->time_diff_flag) {

  1213.                 current->weighting[3] = als_weighting(gb, 1, 16);

  1214.                 current->weighting[4] = als_weighting(gb, 1, 16);

  1215.                 current->weighting[5] = als_weighting(gb, 1, 16);

  1216. 

  1217.                 current->time_diff_sign  = get_bits1(gb);

  1218.                 current->time_diff_index = get_bits(gb, ctx->ltp_lag_length - 3) + 3;

  1219.             }

  1220.         }

  1221. 

  1222.         current++;

  1223.         entries++;

  1224.     }

  1225. 

  1226.     if (entries == channels) {

  1227.         av_log(ctx->avctx, AV_LOG_ERROR, "Damaged channel data.\n");

  1228.         return AVERROR_INVALIDDATA;

  1229.     }

  1230. 

  1231.     align_get_bits(gb);

  1232.     return 0;

  1233. }

  1234. 

  1235. 

  1236. /** Recursively reverts the inter-channel correlation for a block.

  1237.  */

  1238. static int revert_channel_correlation(ALSDecContext *ctx, ALSBlockData *bd,

  1239.                                        ALSChannelData **cd, int *reverted,

  1240.                                        unsigned int offset, int c)

  1241. {

  1242.     ALSChannelData *ch = cd[c];

  1243.     unsigned int   dep = 0;

  1244.     unsigned int channels = ctx->avctx->channels;

  1245. 

  1246.     if (reverted[c])

  1247.         return 0;

  1248. 

  1249.     reverted[c] = 1;

  1250. 

  1251.     while (dep < channels && !ch[dep].stop_flag) {

  1252.         revert_channel_correlation(ctx, bd, cd, reverted, offset,

  1253.                                    ch[dep].master_channel);

  1254. 

  1255.         dep++;

  1256.     }

  1257. 

  1258.     if (dep == channels) {

  1259.         av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel correlation.\n");

  1260.         return AVERROR_INVALIDDATA;

  1261.     }

  1262. 

  1263.     bd->const_block = ctx->const_block + c;

  1264.     bd->shift_lsbs  = ctx->shift_lsbs + c;

  1265.     bd->opt_order   = ctx->opt_order + c;

  1266.     bd->store_prev_samples = ctx->store_prev_samples + c;

  1267.     bd->use_ltp     = ctx->use_ltp + c;

  1268.     bd->ltp_lag     = ctx->ltp_lag + c;

  1269.     bd->ltp_gain    = ctx->ltp_gain[c];

  1270.     bd->lpc_cof     = ctx->lpc_cof[c];

  1271.     bd->quant_cof   = ctx->quant_cof[c];

  1272.     bd->raw_samples = ctx->raw_samples[c] + offset;

  1273. 

  1274.     for (dep = 0; !ch[dep].stop_flag; dep++) {

  1275.         unsigned int smp;

  1276.         unsigned int begin = 1;

  1277.         unsigned int end   = bd->block_length - 1;

  1278.         int64_t y;

  1279.         int32_t *master = ctx->raw_samples[ch[dep].master_channel] + offset;

  1280. 

  1281.         if (ch[dep].master_channel == c)

  1282.             continue;

  1283. 

  1284.         if (ch[dep].time_diff_flag) {

  1285.             int t = ch[dep].time_diff_index;

  1286. 

  1287.             if (ch[dep].time_diff_sign) {

  1288.                 t      = -t;

  1289.                 begin -= t;

  1290.             } else {

  1291.                 end   -= t;

  1292.             }

  1293. 

  1294.             for (smp = begin; smp < end; smp++) {

  1295.                 y  = (1 << 6) +

  1296.                      MUL64(ch[dep].weighting[0], master[smp - 1    ]) +

  1297.                      MUL64(ch[dep].weighting[1], master[smp        ]) +

  1298.                      MUL64(ch[dep].weighting[2], master[smp + 1    ]) +

  1299.                      MUL64(ch[dep].weighting[3], master[smp - 1 + t]) +

  1300.                      MUL64(ch[dep].weighting[4], master[smp     + t]) +

  1301.                      MUL64(ch[dep].weighting[5], master[smp + 1 + t]);

  1302. 

  1303.                 bd->raw_samples[smp] += y >> 7;

  1304.             }

  1305.         } else {

  1306.             for (smp = begin; smp < end; smp++) {

  1307.                 y  = (1 << 6) +

  1308.                      MUL64(ch[dep].weighting[0], master[smp - 1]) +

  1309.                      MUL64(ch[dep].weighting[1], master[smp    ]) +

  1310.                      MUL64(ch[dep].weighting[2], master[smp + 1]);

  1311. 

  1312.                 bd->raw_samples[smp] += y >> 7;

  1313.             }

  1314.         }

  1315.     }

  1316. 

  1317.     return 0;

  1318. }

  1319. 

  1320. 

  1321. /** Read the frame data.

  1322.  */

  1323. static int read_frame_data(ALSDecContext *ctx, unsigned int ra_frame)

  1324. {

  1325.     ALSSpecificConfig *sconf = &ctx->sconf;

  1326.     AVCodecContext *avctx    = ctx->avctx;

  1327.     GetBitContext *gb = &ctx->gb;

  1328.     unsigned int div_blocks[32];                ///< block sizes.

  1329.     unsigned int c;

  1330.     unsigned int js_blocks[2];

  1331.     uint32_t bs_info = 0;

  1332.     int ret;

  1333. 

  1334.     // skip the size of the ra unit if present in the frame

  1335.     if (sconf->ra_flag == RA_FLAG_FRAMES && ra_frame)

  1336.         skip_bits_long(gb, 32);

  1337. 

  1338.     if (sconf->mc_coding && sconf->joint_stereo) {

  1339.         ctx->js_switch = get_bits1(gb);

  1340.         align_get_bits(gb);

  1341.     }

  1342. 

  1343.     if (!sconf->mc_coding || ctx->js_switch) {

  1344.         int independent_bs = !sconf->joint_stereo;

  1345. 

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

  1347.             js_blocks[0] = 0;

  1348.             js_blocks[1] = 0;

  1349. 

  1350.             get_block_sizes(ctx, div_blocks, &bs_info);

  1351. 

  1352.             // if joint_stereo and block_switching is set, independent decoding

  1353.             // is signaled via the first bit of bs_info

  1354.             if (sconf->joint_stereo && sconf->block_switching)

  1355.                 if (bs_info >> 31)

  1356.                     independent_bs = 2;

  1357. 

  1358.             // if this is the last channel, it has to be decoded independently

  1359.             if (c == avctx->channels - 1)

  1360.                 independent_bs = 1;

  1361. 

  1362.             if (independent_bs) {

  1363.                 ret = decode_blocks_ind(ctx, ra_frame, c,

  1364.                                         div_blocks, js_blocks);

  1365.                 if (ret < 0)

  1366.                     return ret;

  1367.                 independent_bs--;

  1368.             } else {

  1369.                 ret = decode_blocks(ctx, ra_frame, c, div_blocks, js_blocks);

  1370.                 if (ret < 0)

  1371.                     return ret;

  1372. 

  1373.                 c++;

  1374.             }

  1375. 

  1376.             // store carryover raw samples

  1377.             memmove(ctx->raw_samples[c] - sconf->max_order,

  1378.                     ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1379.                     sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1380.         }

  1381.     } else { // multi-channel coding

  1382.         ALSBlockData   bd = { 0 };

  1383.         int            b, ret;

  1384.         int            *reverted_channels = ctx->reverted_channels;

  1385.         unsigned int   offset             = 0;

  1386. 

  1387.         for (c = 0; c < avctx->channels; c++)

  1388.             if (ctx->chan_data[c] < ctx->chan_data_buffer) {

  1389.                 av_log(ctx->avctx, AV_LOG_ERROR, "Invalid channel data.\n");

  1390.                 return AVERROR_INVALIDDATA;

  1391.             }

  1392. 

  1393.         memset(reverted_channels, 0, sizeof(*reverted_channels) * avctx->channels);

  1394. 

  1395.         bd.ra_block         = ra_frame;

  1396.         bd.prev_raw_samples = ctx->prev_raw_samples;

  1397. 

  1398.         get_block_sizes(ctx, div_blocks, &bs_info);

  1399. 

  1400.         for (b = 0; b < ctx->num_blocks; b++) {

  1401.             bd.block_length = div_blocks[b];

  1402.             if (bd.block_length <= 0) {

  1403.                 av_log(ctx->avctx, AV_LOG_WARNING,

  1404.                        "Invalid block length %u in channel data!\n",

  1405.                        bd.block_length);

  1406.                 continue;

  1407.             }

  1408. 

  1409.             for (c = 0; c < avctx->channels; c++) {

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

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

  1412.                 bd.opt_order   = ctx->opt_order + c;

  1413.                 bd.store_prev_samples = ctx->store_prev_samples + c;

  1414.                 bd.use_ltp     = ctx->use_ltp + c;

  1415.                 bd.ltp_lag     = ctx->ltp_lag + c;

  1416.                 bd.ltp_gain    = ctx->ltp_gain[c];

  1417.                 bd.lpc_cof     = ctx->lpc_cof[c];

  1418.                 bd.quant_cof   = ctx->quant_cof[c];

  1419.                 bd.raw_samples = ctx->raw_samples[c] + offset;

  1420.                 bd.raw_other   = NULL;

  1421. 

  1422.                 if ((ret = read_block(ctx, &bd)) < 0)

  1423.                     return ret;

  1424.                 if ((ret = read_channel_data(ctx, ctx->chan_data[c], c)) < 0)

  1425.                     return ret;

  1426.             }

  1427. 

  1428.             for (c = 0; c < avctx->channels; c++) {

  1429.                 ret = revert_channel_correlation(ctx, &bd, ctx->chan_data,

  1430.                                                  reverted_channels, offset, c);

  1431.                 if (ret < 0)

  1432.                     return ret;

  1433.             }

  1434.             for (c = 0; c < avctx->channels; c++) {

  1435.                 bd.const_block = ctx->const_block + c;

  1436.                 bd.shift_lsbs  = ctx->shift_lsbs + c;

  1437.                 bd.opt_order   = ctx->opt_order + c;

  1438.                 bd.store_prev_samples = ctx->store_prev_samples + c;

  1439.                 bd.use_ltp     = ctx->use_ltp + c;

  1440.                 bd.ltp_lag     = ctx->ltp_lag + c;

  1441.                 bd.ltp_gain    = ctx->ltp_gain[c];

  1442.                 bd.lpc_cof     = ctx->lpc_cof[c];

  1443.                 bd.quant_cof   = ctx->quant_cof[c];

  1444.                 bd.raw_samples = ctx->raw_samples[c] + offset;

  1445. 

  1446.                 if ((ret = decode_block(ctx, &bd)) < 0)

  1447.                     return ret;

  1448.             }

  1449. 

  1450.             memset(reverted_channels, 0, avctx->channels * sizeof(*reverted_channels));

  1451.             offset      += div_blocks[b];

  1452.             bd.ra_block  = 0;

  1453.         }

  1454. 

  1455.         // store carryover raw samples

  1456.         for (c = 0; c < avctx->channels; c++)

  1457.             memmove(ctx->raw_samples[c] - sconf->max_order,

  1458.                     ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1459.                     sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1460.     }

  1461. 

  1462.     // TODO: read_diff_float_data

  1463. 

  1464.     return 0;

  1465. }

  1466. 

  1467. 

  1468. /** Decode an ALS frame.

  1469.  */

  1470. static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr,

  1471.                         AVPacket *avpkt)

  1472. {

  1473.     ALSDecContext *ctx       = avctx->priv_data;

  1474.     AVFrame *frame           = data;

  1475.     ALSSpecificConfig *sconf = &ctx->sconf;

  1476.     const uint8_t *buffer    = avpkt->data;

  1477.     int buffer_size          = avpkt->size;

  1478.     int invalid_frame, ret;

  1479.     unsigned int c, sample, ra_frame, bytes_read, shift;

  1480. 

  1481.     init_get_bits(&ctx->gb, buffer, buffer_size * 8);

  1482. 

  1483.     // In the case that the distance between random access frames is set to zero

  1484.     // (sconf->ra_distance == 0) no frame is treated as a random access frame.

  1485.     // For the first frame, if prediction is used, all samples used from the

  1486.     // previous frame are assumed to be zero.

  1487.     ra_frame = sconf->ra_distance && !(ctx->frame_id % sconf->ra_distance);

  1488. 

  1489.     // the last frame to decode might have a different length

  1490.     if (sconf->samples != 0xFFFFFFFF)

  1491.         ctx->cur_frame_length = FFMIN(sconf->samples - ctx->frame_id * (uint64_t) sconf->frame_length,

  1492.                                       sconf->frame_length);

  1493.     else

  1494.         ctx->cur_frame_length = sconf->frame_length;

  1495. 

  1496.     // decode the frame data

  1497.     if ((invalid_frame = read_frame_data(ctx, ra_frame)) < 0)

  1498.         av_log(ctx->avctx, AV_LOG_WARNING,

  1499.                "Reading frame data failed. Skipping RA unit.\n");

  1500. 

  1501.     ctx->frame_id++;

  1502. 

  1503.     /* get output buffer */

  1504.     frame->nb_samples = ctx->cur_frame_length;

  1505.     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)

  1506.         return ret;

  1507. 

  1508.     // transform decoded frame into output format

  1509.     #define INTERLEAVE_OUTPUT(bps)                                                   \

  1510.     {                                                                                \

  1511.         int##bps##_t *dest = (int##bps##_t*)frame->data[0];                          \

  1512.         shift = bps - ctx->avctx->bits_per_raw_sample;                               \

  1513.         if (!ctx->cs_switch) {                                                       \

  1514.             for (sample = 0; sample < ctx->cur_frame_length; sample++)               \

  1515.                 for (c = 0; c < avctx->channels; c++)                                \

  1516.                     *dest++ = ctx->raw_samples[c][sample] << shift;                  \

  1517.         } else {                                                                     \

  1518.             for (sample = 0; sample < ctx->cur_frame_length; sample++)               \

  1519.                 for (c = 0; c < avctx->channels; c++)                                \

  1520.                     *dest++ = ctx->raw_samples[sconf->chan_pos[c]][sample] << shift; \

  1521.         }                                                                            \

  1522.     }

  1523. 

  1524.     if (ctx->avctx->bits_per_raw_sample <= 16) {

  1525.         INTERLEAVE_OUTPUT(16)

  1526.     } else {

  1527.         INTERLEAVE_OUTPUT(32)

  1528.     }

  1529. 

  1530.     // update CRC

  1531.     if (sconf->crc_enabled && (avctx->err_recognition & (AV_EF_CRCCHECK|AV_EF_CAREFUL))) {

  1532.         int swap = HAVE_BIGENDIAN != sconf->msb_first;

  1533. 

  1534.         if (ctx->avctx->bits_per_raw_sample == 24) {

  1535.             int32_t *src = (int32_t *)frame->data[0];

  1536. 

  1537.             for (sample = 0;

  1538.                  sample < ctx->cur_frame_length * avctx->channels;

  1539.                  sample++) {

  1540.                 int32_t v;

  1541. 

  1542.                 if (swap)

  1543.                     v = av_bswap32(src[sample]);

  1544.                 else

  1545.                     v = src[sample];

  1546.                 if (!HAVE_BIGENDIAN)

  1547.                     v >>= 8;

  1548. 

  1549.                 ctx->crc = av_crc(ctx->crc_table, ctx->crc, (uint8_t*)(&v), 3);

  1550.             }

  1551.         } else {

  1552.             uint8_t *crc_source;

  1553. 

  1554.             if (swap) {

  1555.                 if (ctx->avctx->bits_per_raw_sample <= 16) {

  1556.                     int16_t *src  = (int16_t*) frame->data[0];

  1557.                     int16_t *dest = (int16_t*) ctx->crc_buffer;

  1558.                     for (sample = 0;

  1559.                          sample < ctx->cur_frame_length * avctx->channels;

  1560.                          sample++)

  1561.                         *dest++ = av_bswap16(src[sample]);

  1562.                 } else {

  1563.                     ctx->dsp.bswap_buf((uint32_t*)ctx->crc_buffer,

  1564.                                        (uint32_t *)frame->data[0],

  1565.                                        ctx->cur_frame_length * avctx->channels);

  1566.                 }

  1567.                 crc_source = ctx->crc_buffer;

  1568.             } else {

  1569.                 crc_source = frame->data[0];

  1570.             }

  1571. 

  1572.             ctx->crc = av_crc(ctx->crc_table, ctx->crc, crc_source,

  1573.                               ctx->cur_frame_length * avctx->channels *

  1574.                               av_get_bytes_per_sample(avctx->sample_fmt));

  1575.         }

  1576. 

  1577. 

  1578.         // check CRC sums if this is the last frame

  1579.         if (ctx->cur_frame_length != sconf->frame_length &&

  1580.             ctx->crc_org != ctx->crc) {

  1581.             av_log(avctx, AV_LOG_ERROR, "CRC error.\n");

  1582.             if (avctx->err_recognition & AV_EF_EXPLODE)

  1583.                 return AVERROR_INVALIDDATA;

  1584.         }

  1585.     }

  1586. 

  1587.     *got_frame_ptr = 1;

  1588. 

  1589.     bytes_read = invalid_frame ? buffer_size :

  1590.                                  (get_bits_count(&ctx->gb) + 7) >> 3;

  1591. 

  1592.     return bytes_read;

  1593. }

  1594. 

  1595. 

  1596. /** Uninitialize the ALS decoder.

  1597.  */

  1598. static av_cold int decode_end(AVCodecContext *avctx)

  1599. {

  1600.     ALSDecContext *ctx = avctx->priv_data;

  1601. 

  1602.     av_freep(&ctx->sconf.chan_pos);

  1603. 

  1604.     ff_bgmc_end(&ctx->bgmc_lut, &ctx->bgmc_lut_status);

  1605. 

  1606.     av_freep(&ctx->const_block);

  1607.     av_freep(&ctx->shift_lsbs);

  1608.     av_freep(&ctx->opt_order);

  1609.     av_freep(&ctx->store_prev_samples);

  1610.     av_freep(&ctx->use_ltp);

  1611.     av_freep(&ctx->ltp_lag);

  1612.     av_freep(&ctx->ltp_gain);

  1613.     av_freep(&ctx->ltp_gain_buffer);

  1614.     av_freep(&ctx->quant_cof);

  1615.     av_freep(&ctx->lpc_cof);

  1616.     av_freep(&ctx->quant_cof_buffer);

  1617.     av_freep(&ctx->lpc_cof_buffer);

  1618.     av_freep(&ctx->lpc_cof_reversed_buffer);

  1619.     av_freep(&ctx->prev_raw_samples);

  1620.     av_freep(&ctx->raw_samples);

  1621.     av_freep(&ctx->raw_buffer);

  1622.     av_freep(&ctx->chan_data);

  1623.     av_freep(&ctx->chan_data_buffer);

  1624.     av_freep(&ctx->reverted_channels);

  1625.     av_freep(&ctx->crc_buffer);

  1626. 

  1627.     return 0;

  1628. }

  1629. 

  1630. 

  1631. /** Initialize the ALS decoder.

  1632.  */

  1633. static av_cold int decode_init(AVCodecContext *avctx)

  1634. {

  1635.     unsigned int c;

  1636.     unsigned int channel_size;

  1637.     int num_buffers, ret;

  1638.     ALSDecContext *ctx = avctx->priv_data;

  1639.     ALSSpecificConfig *sconf = &ctx->sconf;

  1640.     ctx->avctx = avctx;

  1641. 

  1642.     if (!avctx->extradata) {

  1643.         av_log(avctx, AV_LOG_ERROR, "Missing required ALS extradata.\n");

  1644.         return AVERROR_INVALIDDATA;

  1645.     }

  1646. 

  1647.     if ((ret = read_specific_config(ctx)) < 0) {

  1648.         av_log(avctx, AV_LOG_ERROR, "Reading ALSSpecificConfig failed.\n");

  1649.         goto fail;

  1650.     }

  1651. 

  1652.     if ((ret = check_specific_config(ctx)) < 0) {

  1653.         goto fail;

  1654.     }

  1655. 

  1656.     if (sconf->bgmc) {

  1657.         ret = ff_bgmc_init(avctx, &ctx->bgmc_lut, &ctx->bgmc_lut_status);

  1658.         if (ret < 0)

  1659.             goto fail;

  1660.     }

  1661.     if (sconf->floating) {

  1662.         avctx->sample_fmt          = AV_SAMPLE_FMT_FLT;

  1663.         avctx->bits_per_raw_sample = 32;

  1664.     } else {

  1665.         avctx->sample_fmt          = sconf->resolution > 1

  1666.                                      ? AV_SAMPLE_FMT_S32 : AV_SAMPLE_FMT_S16;

  1667.         avctx->bits_per_raw_sample = (sconf->resolution + 1) * 8;

  1668.     }

  1669. 

  1670.     // set maximum Rice parameter for progressive decoding based on resolution

  1671.     // This is not specified in 14496-3 but actually done by the reference

  1672.     // codec RM22 revision 2.

  1673.     ctx->s_max = sconf->resolution > 1 ? 31 : 15;

  1674. 

  1675.     // set lag value for long-term prediction

  1676.     ctx->ltp_lag_length = 8 + (avctx->sample_rate >=  96000) +

  1677.                               (avctx->sample_rate >= 192000);

  1678. 

  1679.     // allocate quantized parcor coefficient buffer

  1680.     num_buffers = sconf->mc_coding ? avctx->channels : 1;

  1681. 

  1682.     ctx->quant_cof        = av_malloc(sizeof(*ctx->quant_cof) * num_buffers);

  1683.     ctx->lpc_cof          = av_malloc(sizeof(*ctx->lpc_cof)   * num_buffers);

  1684.     ctx->quant_cof_buffer = av_malloc(sizeof(*ctx->quant_cof_buffer) *

  1685.                                       num_buffers * sconf->max_order);

  1686.     ctx->lpc_cof_buffer   = av_malloc(sizeof(*ctx->lpc_cof_buffer) *

  1687.                                       num_buffers * sconf->max_order);

  1688.     ctx->lpc_cof_reversed_buffer = av_malloc(sizeof(*ctx->lpc_cof_buffer) *

  1689.                                              sconf->max_order);

  1690. 

  1691.     if (!ctx->quant_cof              || !ctx->lpc_cof        ||

  1692.         !ctx->quant_cof_buffer       || !ctx->lpc_cof_buffer ||

  1693.         !ctx->lpc_cof_reversed_buffer) {

  1694.         av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1695.         ret = AVERROR(ENOMEM);

  1696.         goto fail;

  1697.     }

  1698. 

  1699.     // assign quantized parcor coefficient buffers

  1700.     for (c = 0; c < num_buffers; c++) {

  1701.         ctx->quant_cof[c] = ctx->quant_cof_buffer + c * sconf->max_order;

  1702.         ctx->lpc_cof[c]   = ctx->lpc_cof_buffer   + c * sconf->max_order;

  1703.     }

  1704. 

  1705.     // allocate and assign lag and gain data buffer for ltp mode

  1706.     ctx->const_block     = av_malloc (sizeof(*ctx->const_block) * num_buffers);

  1707.     ctx->shift_lsbs      = av_malloc (sizeof(*ctx->shift_lsbs)  * num_buffers);

  1708.     ctx->opt_order       = av_malloc (sizeof(*ctx->opt_order)   * num_buffers);

  1709.     ctx->store_prev_samples = av_malloc(sizeof(*ctx->store_prev_samples) * num_buffers);

  1710.     ctx->use_ltp         = av_mallocz(sizeof(*ctx->use_ltp)  * num_buffers);

  1711.     ctx->ltp_lag         = av_malloc (sizeof(*ctx->ltp_lag)  * num_buffers);

  1712.     ctx->ltp_gain        = av_malloc (sizeof(*ctx->ltp_gain) * num_buffers);

  1713.     ctx->ltp_gain_buffer = av_malloc (sizeof(*ctx->ltp_gain_buffer) *

  1714.                                       num_buffers * 5);

  1715. 

  1716.     if (!ctx->const_block || !ctx->shift_lsbs ||

  1717.         !ctx->opt_order || !ctx->store_prev_samples ||

  1718.         !ctx->use_ltp  || !ctx->ltp_lag ||

  1719.         !ctx->ltp_gain || !ctx->ltp_gain_buffer) {

  1720.         av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1721.         ret = AVERROR(ENOMEM);

  1722.         goto fail;

  1723.     }

  1724. 

  1725.     for (c = 0; c < num_buffers; c++)

  1726.         ctx->ltp_gain[c] = ctx->ltp_gain_buffer + c * 5;

  1727. 

  1728.     // allocate and assign channel data buffer for mcc mode

  1729.     if (sconf->mc_coding) {

  1730.         ctx->chan_data_buffer  = av_malloc(sizeof(*ctx->chan_data_buffer) *

  1731.                                            num_buffers * num_buffers);

  1732.         ctx->chan_data         = av_malloc(sizeof(*ctx->chan_data) *

  1733.                                            num_buffers);

  1734.         ctx->reverted_channels = av_malloc(sizeof(*ctx->reverted_channels) *

  1735.                                            num_buffers);

  1736. 

  1737.         if (!ctx->chan_data_buffer || !ctx->chan_data || !ctx->reverted_channels) {

  1738.             av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1739.             ret = AVERROR(ENOMEM);

  1740.             goto fail;

  1741.         }

  1742. 

  1743.         for (c = 0; c < num_buffers; c++)

  1744.             ctx->chan_data[c] = ctx->chan_data_buffer + c * num_buffers;

  1745.     } else {

  1746.         ctx->chan_data         = NULL;

  1747.         ctx->chan_data_buffer  = NULL;

  1748.         ctx->reverted_channels = NULL;

  1749.     }

  1750. 

  1751.     channel_size      = sconf->frame_length + sconf->max_order;

  1752. 

  1753.     ctx->prev_raw_samples = av_malloc (sizeof(*ctx->prev_raw_samples) * sconf->max_order);

  1754.     ctx->raw_buffer       = av_mallocz(sizeof(*ctx->     raw_buffer)  * avctx->channels * channel_size);

  1755.     ctx->raw_samples      = av_malloc (sizeof(*ctx->     raw_samples) * avctx->channels);

  1756. 

  1757.     // allocate previous raw sample buffer

  1758.     if (!ctx->prev_raw_samples || !ctx->raw_buffer|| !ctx->raw_samples) {

  1759.         av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1760.         ret = AVERROR(ENOMEM);

  1761.         goto fail;

  1762.     }

  1763. 

  1764.     // assign raw samples buffers

  1765.     ctx->raw_samples[0] = ctx->raw_buffer + sconf->max_order;

  1766.     for (c = 1; c < avctx->channels; c++)

  1767.         ctx->raw_samples[c] = ctx->raw_samples[c - 1] + channel_size;

  1768. 

  1769.     // allocate crc buffer

  1770.     if (HAVE_BIGENDIAN != sconf->msb_first && sconf->crc_enabled &&

  1771.         (avctx->err_recognition & (AV_EF_CRCCHECK|AV_EF_CAREFUL))) {

  1772.         ctx->crc_buffer = av_malloc(sizeof(*ctx->crc_buffer) *

  1773.                                     ctx->cur_frame_length *

  1774.                                     avctx->channels *

  1775.                                     av_get_bytes_per_sample(avctx->sample_fmt));

  1776.         if (!ctx->crc_buffer) {

  1777.             av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1778.             ret = AVERROR(ENOMEM);

  1779.             goto fail;

  1780.         }

  1781.     }

  1782. 

  1783.     ff_dsputil_init(&ctx->dsp, avctx);

  1784. 

  1785.     return 0;

  1786. 

  1787. fail:

  1788.     decode_end(avctx);

  1789.     return ret;

  1790. }

  1791. 

  1792. 

  1793. /** Flush (reset) the frame ID after seeking.

  1794.  */

  1795. static av_cold void flush(AVCodecContext *avctx)

  1796. {

  1797.     ALSDecContext *ctx = avctx->priv_data;

  1798. 

  1799.     ctx->frame_id = 0;

  1800. }

  1801. 

  1802. 

  1803. AVCodec ff_als_decoder = {

  1804.     .name           = "als",

  1805.     .long_name      = NULL_IF_CONFIG_SMALL("MPEG-4 Audio Lossless Coding (ALS)"),

  1806.     .type           = AVMEDIA_TYPE_AUDIO,

  1807.     .id             = AV_CODEC_ID_MP4ALS,

  1808.     .priv_data_size = sizeof(ALSDecContext),

  1809.     .init           = decode_init,

  1810.     .close          = decode_end,

  1811.     .decode         = decode_frame,

  1812.     .flush          = flush,

  1813.     .capabilities   = CODEC_CAP_SUBFRAMES | CODEC_CAP_DR1,

  1814. };