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FFmpeg/libavcodec/alsdec.c

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  1. /*

  2.  * MPEG-4 ALS decoder

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

  4.  *

  5.  * This file is part of FFmpeg.

  6.  *

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

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

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

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

  11.  *

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

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

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

  15.  * Lesser General Public License for more details.

  16.  *

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

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

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

  20.  */

  21. 

  22. /**

  23.  * @file

  24.  * MPEG-4 ALS decoder

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

  26.  */

  27. 

  28. 

  29. //#define DEBUG

  30. 

  31. 

  32. #include "avcodec.h"

  33. #include "get_bits.h"

  34. #include "unary.h"

  35. #include "mpeg4audio.h"

  36. #include "bytestream.h"

  37. #include "bgmc.h"

  38. #include "dsputil.h"

  39. #include "internal.h"

  40. #include "libavutil/samplefmt.h"

  41. #include "libavutil/crc.h"

  42. 

  43. #include <stdint.h>

  44. 

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

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

  47.  *  by the encoder and stored in ALSSpecificConfig.

  48.  */

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

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

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

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

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

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

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

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

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

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

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

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

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

  62. };

  63. 

  64. 

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

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

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

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

  69.  */

  70. static const int16_t parcor_scaled_values[] = {

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  103. };

  104. 

  105. 

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

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

  108.  */

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

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

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

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

  113.     {88, 92, 96, 100}

  114. };

  115. 

  116. 

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

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

  119.  */

  120. static const int16_t mcc_weightings[] = {

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

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

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

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

  125. };

  126. 

  127. 

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

  129.  */

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  147. };

  148. 

  149. 

  150. enum RA_Flag {

  151.     RA_FLAG_NONE,

  152.     RA_FLAG_FRAMES,

  153.     RA_FLAG_HEADER

  154. };

  155. 

  156. 

  157. typedef struct {

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  180. } ALSSpecificConfig;

  181. 

  182. 

  183. typedef struct {

  184.     int stop_flag;

  185.     int master_channel;

  186.     int time_diff_flag;

  187.     int time_diff_sign;

  188.     int time_diff_index;

  189.     int weighting[6];

  190. } ALSChannelData;

  191. 

  192. 

  193. typedef struct {

  194.     AVCodecContext *avctx;

  195.     AVFrame frame;

  196.     ALSSpecificConfig sconf;

  197.     GetBitContext gb;

  198.     DSPContext dsp;

  199.     const AVCRC *crc_table;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  231. } ALSDecContext;

  232. 

  233. 

  234. typedef struct {

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  250. } ALSBlockData;

  251. 

  252. 

  253. static av_cold void dprint_specific_config(ALSDecContext *ctx)

  254. {

  255. #ifdef DEBUG

  256.     AVCodecContext *avctx    = ctx->avctx;

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

  258. 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  277. #endif

  278. }

  279. 

  280. 

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

  282.  */

  283. static av_cold int read_specific_config(ALSDecContext *ctx)

  284. {

  285.     GetBitContext gb;

  286.     uint64_t ht_size;

  287.     int i, config_offset;

  288.     MPEG4AudioConfig m4ac;

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

  290.     AVCodecContext *avctx    = ctx->avctx;

  291.     uint32_t als_id, header_size, trailer_size;

  292.     int ret;

  293. 

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

  295.         return ret;

  296. 

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

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

  299. 

  300.     if (config_offset < 0)

  301.         return -1;

  302. 

  303.     skip_bits_long(&gb, config_offset);

  304. 

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

  306.         return -1;

  307. 

  308.     // read the fixed items

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

  310.     avctx->sample_rate          = m4ac.sample_rate;

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

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

  313.     avctx->channels             = m4ac.channels;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  337. 

  338. 

  339.     // check for ALSSpecificConfig struct

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

  341.         return -1;

  342. 

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

  344. 

  345.     // read channel config

  346.     if (sconf->chan_config)

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

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

  349. 

  350. 

  351.     // read channel sorting

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

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

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

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

  356.             return -1;

  357. 

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

  359.             return AVERROR(ENOMEM);

  360. 

  361.         ctx->cs_switch = 1;

  362. 

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

  364.             int idx;

  365. 

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

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

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

  369.                 ctx->cs_switch = 0;

  370.                 break;

  371.             }

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

  373.         }

  374. 

  375.         align_get_bits(&gb);

  376.     }

  377. 

  378. 

  379.     // read fixed header and trailer sizes,

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

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

  382.         return -1;

  383. 

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

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

  386.     if (header_size  == 0xFFFFFFFF)

  387.         header_size  = 0;

  388.     if (trailer_size == 0xFFFFFFFF)

  389.         trailer_size = 0;

  390. 

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

  392. 

  393. 

  394.     // skip the header and trailer data

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

  396.         return -1;

  397. 

  398.     if (ht_size > INT32_MAX)

  399.         return -1;

  400. 

  401.     skip_bits_long(&gb, ht_size);

  402. 

  403. 

  404.     // initialize CRC calculation

  405.     if (sconf->crc_enabled) {

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

  407.             return -1;

  408. 

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

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

  411.             ctx->crc       = 0xFFFFFFFF;

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

  413.         } else

  414.             skip_bits_long(&gb, 32);

  415.     }

  416. 

  417. 

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

  419. 

  420.     dprint_specific_config(ctx);

  421. 

  422.     return 0;

  423. }

  424. 

  425. 

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

  427.  */

  428. static int check_specific_config(ALSDecContext *ctx)

  429. {

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

  431.     int error = 0;

  432. 

  433.     // report unsupported feature and set error value

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

  435.     {                                                   \

  436.         if (cond) {                                     \

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

  438.             error = errval;                             \

  439.         }                                               \

  440.     }

  441. 

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

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

  444. 

  445.     return error;

  446. }

  447. 

  448. 

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

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

  451.  */

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

  453.                           unsigned int div, unsigned int **div_blocks,

  454.                           unsigned int *num_blocks)

  455. {

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

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

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

  459.         n   *= 2;

  460.         div += 1;

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

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

  463.     } else {

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

  465.         // (bit implicitly not set)

  466.         **div_blocks = div;

  467.         (*div_blocks)++;

  468.         (*num_blocks)++;

  469.     }

  470. }

  471. 

  472. 

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

  474.  */

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

  476. {

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

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

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

  480. 

  481.     if (k > 1) {

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

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

  484.     } else if (!k) {

  485.         q >>= 1;

  486.     }

  487.     return r ? q : ~q;

  488. }

  489. 

  490. 

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

  492.  */

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

  494. {

  495.     int i, j;

  496. 

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

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

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

  500.         cof[i]  += tmp1;

  501.     }

  502.     if (i == j)

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

  504. 

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

  506. }

  507. 

  508. 

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

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

  511.  *  actual number of samples.

  512.  */

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

  514.                             uint32_t *bs_info)

  515. {

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

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

  518.     unsigned int *ptr_div_blocks = div_blocks;

  519.     unsigned int b;

  520. 

  521.     if (sconf->block_switching) {

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

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

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

  525.     }

  526. 

  527.     ctx->num_blocks = 0;

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

  529. 

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

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

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

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

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

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

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

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

  538.     // codec RM22 revision 2.

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

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

  541.     // of 14496-3.

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

  543.     // frame.

  544. 

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

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

  547. 

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

  549.         unsigned int remaining = ctx->cur_frame_length;

  550. 

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

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

  553.                 div_blocks[b] = remaining;

  554.                 ctx->num_blocks = b + 1;

  555.                 break;

  556.             }

  557. 

  558.             remaining -= div_blocks[b];

  559.         }

  560.     }

  561. }

  562. 

  563. 

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

  565.  */

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

  567. {

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

  569.     AVCodecContext *avctx    = ctx->avctx;

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

  571. 

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

  573.         return AVERROR_INVALIDDATA;

  574. 

  575.     *bd->raw_samples = 0;

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

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

  578. 

  579.     // skip 5 reserved bits

  580.     skip_bits(gb, 5);

  581. 

  582.     if (*bd->const_block) {

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

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

  585.     }

  586. 

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

  588.     *bd->const_block = 1;

  589. 

  590.     return 0;

  591. }

  592. 

  593. 

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

  595.  */

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

  597. {

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

  599.     int32_t  val = *bd->raw_samples;

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

  601. 

  602.     // write raw samples into buffer

  603.     for (; smp; smp--)

  604.         *dst++ = val;

  605. }

  606. 

  607. 

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

  609.  */

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

  611. {

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

  613.     AVCodecContext *avctx    = ctx->avctx;

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

  615.     unsigned int k;

  616.     unsigned int s[8];

  617.     unsigned int sx[8];

  618.     unsigned int sub_blocks, log2_sub_blocks, sb_length;

  619.     unsigned int start      = 0;

  620.     unsigned int opt_order;

  621.     int          sb;

  622.     int32_t      *quant_cof = bd->quant_cof;

  623.     int32_t      *current_res;

  624. 

  625. 

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

  627.     *bd->const_block = 0;

  628. 

  629.     *bd->opt_order  = 1;

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

  631. 

  632.     opt_order       = *bd->opt_order;

  633. 

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

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

  636.         log2_sub_blocks = 0;

  637.     } else {

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

  639.             log2_sub_blocks = get_bits(gb, 2);

  640.         else

  641.             log2_sub_blocks = 2 * get_bits1(gb);

  642.     }

  643. 

  644.     sub_blocks = 1 << log2_sub_blocks;

  645. 

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

  647.     // block_length must be evenly divisible by sub_blocks

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

  649.         av_log(avctx, AV_LOG_WARNING,

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

  651.         return -1;

  652.     }

  653. 

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

  655. 

  656.     if (sconf->bgmc) {

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

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

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

  660. 

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

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

  663.             s [k] >>= 4;

  664.         }

  665.     } else {

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

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

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

  669.     }

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

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

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

  673.             return AVERROR_INVALIDDATA;

  674.         }

  675. 

  676.     if (get_bits1(gb))

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

  678. 

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

  680. 

  681. 

  682.     if (!sconf->rlslms) {

  683.         if (sconf->adapt_order) {

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

  685.                                                 2, sconf->max_order + 1));

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

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

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

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

  690.                 return AVERROR_INVALIDDATA;

  691.             }

  692.         } else {

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

  694.         }

  695. 

  696.         opt_order = *bd->opt_order;

  697. 

  698.         if (opt_order) {

  699.             int add_base;

  700. 

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

  702.                 add_base = 0x7F;

  703. 

  704.                 // read coefficient 0

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

  706. 

  707.                 // read coefficient 1

  708.                 if (opt_order > 1)

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

  710. 

  711.                 // read coefficients 2 to opt_order

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

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

  714.             } else {

  715.                 int k_max;

  716.                 add_base = 1;

  717. 

  718.                 // read coefficient 0 to 19

  719.                 k_max = FFMIN(opt_order, 20);

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

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

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

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

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

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

  726.                         return AVERROR_INVALIDDATA;

  727.                     }

  728.                 }

  729. 

  730.                 // read coefficients 20 to 126

  731.                 k_max = FFMIN(opt_order, 127);

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

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

  734. 

  735.                 // read coefficients 127 to opt_order

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

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

  738. 

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

  740. 

  741.                 if (opt_order > 1)

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

  743.             }

  744. 

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

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

  747.         }

  748.     }

  749. 

  750.     // read LTP gain and lag values

  751.     if (sconf->long_term_prediction) {

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

  753. 

  754.         if (*bd->use_ltp) {

  755.             int r, c;

  756. 

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

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

  759. 

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

  761.             c                 = get_bits(gb, 2);

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

  763. 

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

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

  766. 

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

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

  769.         }

  770.     }

  771. 

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

  773.     if (bd->ra_block) {

  774.         if (opt_order)

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

  776.         if (opt_order > 1)

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

  778.         if (opt_order > 2)

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

  780. 

  781.         start = FFMIN(opt_order, 3);

  782.     }

  783. 

  784.     // read all residuals

  785.     if (sconf->bgmc) {

  786.         int          delta[8];

  787.         unsigned int k    [8];

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

  789. 

  790.         // read most significant bits

  791.         unsigned int high;

  792.         unsigned int low;

  793.         unsigned int value;

  794. 

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

  796. 

  797.         current_res = bd->raw_samples + start;

  798. 

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

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

  801. 

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

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

  804. 

  805.             ff_bgmc_decode(gb, sb_len, current_res,

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

  807. 

  808.             current_res += sb_len;

  809.         }

  810. 

  811.         ff_bgmc_decode_end(gb);

  812. 

  813. 

  814.         // read least significant bits and tails

  815.         current_res = bd->raw_samples + start;

  816. 

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

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

  819.             unsigned int cur_k         = k[sb];

  820.             unsigned int cur_s         = s[sb];

  821. 

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

  823.                 int32_t res = *current_res;

  824. 

  825.                 if (res == cur_tail_code) {

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

  827.                                           << (5 - delta[sb]);

  828. 

  829.                     res = decode_rice(gb, cur_s);

  830. 

  831.                     if (res >= 0) {

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

  833.                     } else {

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

  835.                     }

  836.                 } else {

  837.                     if (res > cur_tail_code)

  838.                         res--;

  839. 

  840.                     if (res & 1)

  841.                         res = -res;

  842. 

  843.                     res >>= 1;

  844. 

  845.                     if (cur_k) {

  846.                         res <<= cur_k;

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

  848.                     }

  849.                 }

  850. 

  851.                 *current_res++ = res;

  852.             }

  853.         }

  854.     } else {

  855.         current_res = bd->raw_samples + start;

  856. 

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

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

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

  860.      }

  861. 

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

  863.         align_get_bits(gb);

  864. 

  865.     return 0;

  866. }

  867. 

  868. 

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

  870.  */

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

  872. {

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

  874.     unsigned int block_length = bd->block_length;

  875.     unsigned int smp = 0;

  876.     unsigned int k;

  877.     int opt_order             = *bd->opt_order;

  878.     int sb;

  879.     int64_t y;

  880.     int32_t *quant_cof        = bd->quant_cof;

  881.     int32_t *lpc_cof          = bd->lpc_cof;

  882.     int32_t *raw_samples      = bd->raw_samples;

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

  884.     int32_t *lpc_cof_reversed = ctx->lpc_cof_reversed_buffer;

  885. 

  886.     // reverse long-term prediction

  887.     if (*bd->use_ltp) {

  888.         int ltp_smp;

  889. 

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

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

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

  893.             int end    = center + 3;

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

  895.             int base;

  896. 

  897.             y = 1 << 6;

  898. 

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

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

  901. 

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

  903.         }

  904.     }

  905. 

  906.     // reconstruct all samples from residuals

  907.     if (bd->ra_block) {

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

  909.             y = 1 << 19;

  910. 

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

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

  913. 

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

  915.             parcor_to_lpc(smp, quant_cof, lpc_cof);

  916.         }

  917.     } else {

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

  919.             parcor_to_lpc(k, quant_cof, lpc_cof);

  920. 

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

  922.         if (*bd->store_prev_samples)

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

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

  925. 

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

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

  928.             int32_t *left, *right;

  929. 

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

  931.                 left  = raw_samples;

  932.                 right = bd->raw_other;

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

  934.                 left  = bd->raw_other;

  935.                 right = raw_samples;

  936.             }

  937. 

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

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

  940.         }

  941. 

  942.         // reconstruct shifted signal

  943.         if (*bd->shift_lsbs)

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

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

  946.     }

  947. 

  948.     // reverse linear prediction coefficients for efficiency

  949.     lpc_cof = lpc_cof + opt_order;

  950. 

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

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

  953. 

  954.     // reconstruct raw samples

  955.     raw_samples = bd->raw_samples + smp;

  956.     lpc_cof     = lpc_cof_reversed + opt_order;

  957. 

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

  959.         y = 1 << 19;

  960. 

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

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

  963. 

  964.         *raw_samples -= y >> 20;

  965.     }

  966. 

  967.     raw_samples = bd->raw_samples;

  968. 

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

  970.     if (*bd->store_prev_samples)

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

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

  973. 

  974.     return 0;

  975. }

  976. 

  977. 

  978. /** Read the block data.

  979.  */

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

  981. {

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

  983.     int ret;

  984. 

  985.     *bd->shift_lsbs = 0;

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

  987.     if (get_bits1(gb)) {

  988.         if ((ret = read_var_block_data(ctx, bd)) < 0)

  989.             return ret;

  990.     } else {

  991.         if ((ret = read_const_block_data(ctx, bd)) < 0)

  992.             return ret;

  993.     }

  994. 

  995.     return 0;

  996. }

  997. 

  998. 

  999. /** Decode the block data.

  1000.  */

  1001. static int decode_block(ALSDecContext *ctx, ALSBlockData *bd)

  1002. {

  1003.     unsigned int smp;

  1004. 

  1005.     // read block type flag and read the samples accordingly

  1006.     if (*bd->const_block)

  1007.         decode_const_block_data(ctx, bd);

  1008.     else if (decode_var_block_data(ctx, bd))

  1009.         return -1;

  1010. 

  1011.     // TODO: read RLSLMS extension data

  1012. 

  1013.     if (*bd->shift_lsbs)

  1014.         for (smp = 0; smp < bd->block_length; smp++)

  1015.             bd->raw_samples[smp] <<= *bd->shift_lsbs;

  1016. 

  1017.     return 0;

  1018. }

  1019. 

  1020. 

  1021. /** Read and decode block data successively.

  1022.  */

  1023. static int read_decode_block(ALSDecContext *ctx, ALSBlockData *bd)

  1024. {

  1025.     int ret;

  1026. 

  1027.     ret = read_block(ctx, bd);

  1028. 

  1029.     if (ret)

  1030.         return ret;

  1031. 

  1032.     ret = decode_block(ctx, bd);

  1033. 

  1034.     return ret;

  1035. }

  1036. 

  1037. 

  1038. /** Compute the number of samples left to decode for the current frame and

  1039.  *  sets these samples to zero.

  1040.  */

  1041. static void zero_remaining(unsigned int b, unsigned int b_max,

  1042.                            const unsigned int *div_blocks, int32_t *buf)

  1043. {

  1044.     unsigned int count = 0;

  1045. 

  1046.     while (b < b_max)

  1047.         count += div_blocks[b++];

  1048. 

  1049.     if (count)

  1050.         memset(buf, 0, sizeof(*buf) * count);

  1051. }

  1052. 

  1053. 

  1054. /** Decode blocks independently.

  1055.  */

  1056. static int decode_blocks_ind(ALSDecContext *ctx, unsigned int ra_frame,

  1057.                              unsigned int c, const unsigned int *div_blocks,

  1058.                              unsigned int *js_blocks)

  1059. {

  1060.     unsigned int b;

  1061.     ALSBlockData bd = { 0 };

  1062. 

  1063.     bd.ra_block         = ra_frame;

  1064.     bd.const_block      = ctx->const_block;

  1065.     bd.shift_lsbs       = ctx->shift_lsbs;

  1066.     bd.opt_order        = ctx->opt_order;

  1067.     bd.store_prev_samples = ctx->store_prev_samples;

  1068.     bd.use_ltp          = ctx->use_ltp;

  1069.     bd.ltp_lag          = ctx->ltp_lag;

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

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

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

  1073.     bd.prev_raw_samples = ctx->prev_raw_samples;

  1074.     bd.raw_samples      = ctx->raw_samples[c];

  1075. 

  1076. 

  1077.     for (b = 0; b < ctx->num_blocks; b++) {

  1078.         bd.block_length     = div_blocks[b];

  1079. 

  1080.         if (read_decode_block(ctx, &bd)) {

  1081.             // damaged block, write zero for the rest of the frame

  1082.             zero_remaining(b, ctx->num_blocks, div_blocks, bd.raw_samples);

  1083.             return -1;

  1084.         }

  1085.         bd.raw_samples += div_blocks[b];

  1086.         bd.ra_block     = 0;

  1087.     }

  1088. 

  1089.     return 0;

  1090. }

  1091. 

  1092. 

  1093. /** Decode blocks dependently.

  1094.  */

  1095. static int decode_blocks(ALSDecContext *ctx, unsigned int ra_frame,

  1096.                          unsigned int c, const unsigned int *div_blocks,

  1097.                          unsigned int *js_blocks)

  1098. {

  1099.     ALSSpecificConfig *sconf = &ctx->sconf;

  1100.     unsigned int offset = 0;

  1101.     unsigned int b;

  1102.     ALSBlockData bd[2] = { { 0 } };

  1103. 

  1104.     bd[0].ra_block         = ra_frame;

  1105.     bd[0].const_block      = ctx->const_block;

  1106.     bd[0].shift_lsbs       = ctx->shift_lsbs;

  1107.     bd[0].opt_order        = ctx->opt_order;

  1108.     bd[0].store_prev_samples = ctx->store_prev_samples;

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

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

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

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

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

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

  1115.     bd[0].js_blocks        = *js_blocks;

  1116. 

  1117.     bd[1].ra_block         = ra_frame;

  1118.     bd[1].const_block      = ctx->const_block;

  1119.     bd[1].shift_lsbs       = ctx->shift_lsbs;

  1120.     bd[1].opt_order        = ctx->opt_order;

  1121.     bd[1].store_prev_samples = ctx->store_prev_samples;

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

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

  1124.     bd[1].ltp_gain         = ctx->ltp_gain[0];

  1125.     bd[1].quant_cof        = ctx->quant_cof[0];

  1126.     bd[1].lpc_cof          = ctx->lpc_cof[0];

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

  1128.     bd[1].js_blocks        = *(js_blocks + 1);

  1129. 

  1130.     // decode all blocks

  1131.     for (b = 0; b < ctx->num_blocks; b++) {

  1132.         unsigned int s;

  1133. 

  1134.         bd[0].block_length = div_blocks[b];

  1135.         bd[1].block_length = div_blocks[b];

  1136. 

  1137.         bd[0].raw_samples  = ctx->raw_samples[c    ] + offset;

  1138.         bd[1].raw_samples  = ctx->raw_samples[c + 1] + offset;

  1139. 

  1140.         bd[0].raw_other    = bd[1].raw_samples;

  1141.         bd[1].raw_other    = bd[0].raw_samples;

  1142. 

  1143.         if(read_decode_block(ctx, &bd[0]) || read_decode_block(ctx, &bd[1])) {

  1144.             // damaged block, write zero for the rest of the frame

  1145.             zero_remaining(b, ctx->num_blocks, div_blocks, bd[0].raw_samples);

  1146.             zero_remaining(b, ctx->num_blocks, div_blocks, bd[1].raw_samples);

  1147.             return -1;

  1148.         }

  1149. 

  1150.         // reconstruct joint-stereo blocks

  1151.         if (bd[0].js_blocks) {

  1152.             if (bd[1].js_blocks)

  1153.                 av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel pair.\n");

  1154. 

  1155.             for (s = 0; s < div_blocks[b]; s++)

  1156.                 bd[0].raw_samples[s] = bd[1].raw_samples[s] - bd[0].raw_samples[s];

  1157.         } else if (bd[1].js_blocks) {

  1158.             for (s = 0; s < div_blocks[b]; s++)

  1159.                 bd[1].raw_samples[s] = bd[1].raw_samples[s] + bd[0].raw_samples[s];

  1160.         }

  1161. 

  1162.         offset  += div_blocks[b];

  1163.         bd[0].ra_block = 0;

  1164.         bd[1].ra_block = 0;

  1165.     }

  1166. 

  1167.     // store carryover raw samples,

  1168.     // the others channel raw samples are stored by the calling function.

  1169.     memmove(ctx->raw_samples[c] - sconf->max_order,

  1170.             ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1171.             sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1172. 

  1173.     return 0;

  1174. }

  1175. 

  1176. 

  1177. /** Read the channel data.

  1178.   */

  1179. static int read_channel_data(ALSDecContext *ctx, ALSChannelData *cd, int c)

  1180. {

  1181.     GetBitContext *gb       = &ctx->gb;

  1182.     ALSChannelData *current = cd;

  1183.     unsigned int channels   = ctx->avctx->channels;

  1184.     int entries             = 0;

  1185. 

  1186.     while (entries < channels && !(current->stop_flag = get_bits1(gb))) {

  1187.         current->master_channel = get_bits_long(gb, av_ceil_log2(channels));

  1188. 

  1189.         if (current->master_channel >= channels) {

  1190.             av_log(ctx->avctx, AV_LOG_ERROR, "Invalid master channel.\n");

  1191.             return -1;

  1192.         }

  1193. 

  1194.         if (current->master_channel != c) {

  1195.             current->time_diff_flag = get_bits1(gb);

  1196.             current->weighting[0]   = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 31)];

  1197.             current->weighting[1]   = mcc_weightings[av_clip(decode_rice(gb, 2) + 14, 0, 31)];

  1198.             current->weighting[2]   = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 31)];

  1199. 

  1200.             if (current->time_diff_flag) {

  1201.                 current->weighting[3] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 31)];

  1202.                 current->weighting[4] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 31)];

  1203.                 current->weighting[5] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 31)];

  1204. 

  1205.                 current->time_diff_sign  = get_bits1(gb);

  1206.                 current->time_diff_index = get_bits(gb, ctx->ltp_lag_length - 3) + 3;

  1207.             }

  1208.         }

  1209. 

  1210.         current++;

  1211.         entries++;

  1212.     }

  1213. 

  1214.     if (entries == channels) {

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

  1216.         return -1;

  1217.     }

  1218. 

  1219.     align_get_bits(gb);

  1220.     return 0;

  1221. }

  1222. 

  1223. 

  1224. /** Recursively reverts the inter-channel correlation for a block.

  1225.  */

  1226. static int revert_channel_correlation(ALSDecContext *ctx, ALSBlockData *bd,

  1227.                                        ALSChannelData **cd, int *reverted,

  1228.                                        unsigned int offset, int c)

  1229. {

  1230.     ALSChannelData *ch = cd[c];

  1231.     unsigned int   dep = 0;

  1232.     unsigned int channels = ctx->avctx->channels;

  1233. 

  1234.     if (reverted[c])

  1235.         return 0;

  1236. 

  1237.     reverted[c] = 1;

  1238. 

  1239.     while (dep < channels && !ch[dep].stop_flag) {

  1240.         revert_channel_correlation(ctx, bd, cd, reverted, offset,

  1241.                                    ch[dep].master_channel);

  1242. 

  1243.         dep++;

  1244.     }

  1245. 

  1246.     if (dep == channels) {

  1247.         av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel correlation.\n");

  1248.         return -1;

  1249.     }

  1250. 

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

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

  1253.     bd->opt_order   = ctx->opt_order + c;

  1254.     bd->store_prev_samples = ctx->store_prev_samples + c;

  1255.     bd->use_ltp     = ctx->use_ltp + c;

  1256.     bd->ltp_lag     = ctx->ltp_lag + c;

  1257.     bd->ltp_gain    = ctx->ltp_gain[c];

  1258.     bd->lpc_cof     = ctx->lpc_cof[c];

  1259.     bd->quant_cof   = ctx->quant_cof[c];

  1260.     bd->raw_samples = ctx->raw_samples[c] + offset;

  1261. 

  1262.     dep = 0;

  1263.     while (!ch[dep].stop_flag) {

  1264.         unsigned int smp;

  1265.         unsigned int begin = 1;

  1266.         unsigned int end   = bd->block_length - 1;

  1267.         int64_t y;

  1268.         int32_t *master = ctx->raw_samples[ch[dep].master_channel] + offset;

  1269. 

  1270.         if (ch[dep].time_diff_flag) {

  1271.             int t = ch[dep].time_diff_index;

  1272. 

  1273.             if (ch[dep].time_diff_sign) {

  1274.                 t      = -t;

  1275.                 begin -= t;

  1276.             } else {

  1277.                 end   -= t;

  1278.             }

  1279. 

  1280.             for (smp = begin; smp < end; smp++) {

  1281.                 y  = (1 << 6) +

  1282.                      MUL64(ch[dep].weighting[0], master[smp - 1    ]) +

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

  1284.                      MUL64(ch[dep].weighting[2], master[smp + 1    ]) +

  1285.                      MUL64(ch[dep].weighting[3], master[smp - 1 + t]) +

  1286.                      MUL64(ch[dep].weighting[4], master[smp     + t]) +

  1287.                      MUL64(ch[dep].weighting[5], master[smp + 1 + t]);

  1288. 

  1289.                 bd->raw_samples[smp] += y >> 7;

  1290.             }

  1291.         } else {

  1292.             for (smp = begin; smp < end; smp++) {

  1293.                 y  = (1 << 6) +

  1294.                      MUL64(ch[dep].weighting[0], master[smp - 1]) +

  1295.                      MUL64(ch[dep].weighting[1], master[smp    ]) +

  1296.                      MUL64(ch[dep].weighting[2], master[smp + 1]);

  1297. 

  1298.                 bd->raw_samples[smp] += y >> 7;

  1299.             }

  1300.         }

  1301. 

  1302.         dep++;

  1303.     }

  1304. 

  1305.     return 0;

  1306. }

  1307. 

  1308. 

  1309. /** Read the frame data.

  1310.  */

  1311. static int read_frame_data(ALSDecContext *ctx, unsigned int ra_frame)

  1312. {

  1313.     ALSSpecificConfig *sconf = &ctx->sconf;

  1314.     AVCodecContext *avctx    = ctx->avctx;

  1315.     GetBitContext *gb = &ctx->gb;

  1316.     unsigned int div_blocks[32];                ///< block sizes.

  1317.     unsigned int c;

  1318.     unsigned int js_blocks[2];

  1319. 

  1320.     uint32_t bs_info = 0;

  1321. 

  1322.     // skip the size of the ra unit if present in the frame

  1323.     if (sconf->ra_flag == RA_FLAG_FRAMES && ra_frame)

  1324.         skip_bits_long(gb, 32);

  1325. 

  1326.     if (sconf->mc_coding && sconf->joint_stereo) {

  1327.         ctx->js_switch = get_bits1(gb);

  1328.         align_get_bits(gb);

  1329.     }

  1330. 

  1331.     if (!sconf->mc_coding || ctx->js_switch) {

  1332.         int independent_bs = !sconf->joint_stereo;

  1333. 

  1334.         for (c = 0; c < avctx->channels; c++) {

  1335.             js_blocks[0] = 0;

  1336.             js_blocks[1] = 0;

  1337. 

  1338.             get_block_sizes(ctx, div_blocks, &bs_info);

  1339. 

  1340.             // if joint_stereo and block_switching is set, independent decoding

  1341.             // is signaled via the first bit of bs_info

  1342.             if (sconf->joint_stereo && sconf->block_switching)

  1343.                 if (bs_info >> 31)

  1344.                     independent_bs = 2;

  1345. 

  1346.             // if this is the last channel, it has to be decoded independently

  1347.             if (c == avctx->channels - 1)

  1348.                 independent_bs = 1;

  1349. 

  1350.             if (independent_bs) {

  1351.                 if (decode_blocks_ind(ctx, ra_frame, c, div_blocks, js_blocks))

  1352.                     return -1;

  1353. 

  1354.                 independent_bs--;

  1355.             } else {

  1356.                 if (decode_blocks(ctx, ra_frame, c, div_blocks, js_blocks))

  1357.                     return -1;

  1358. 

  1359.                 c++;

  1360.             }

  1361. 

  1362.             // store carryover raw samples

  1363.             memmove(ctx->raw_samples[c] - sconf->max_order,

  1364.                     ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1365.                     sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1366.         }

  1367.     } else { // multi-channel coding

  1368.         ALSBlockData   bd = { 0 };

  1369.         int            b, ret;

  1370.         int            *reverted_channels = ctx->reverted_channels;

  1371.         unsigned int   offset             = 0;

  1372. 

  1373.         for (c = 0; c < avctx->channels; c++)

  1374.             if (ctx->chan_data[c] < ctx->chan_data_buffer) {

  1375.                 av_log(ctx->avctx, AV_LOG_ERROR, "Invalid channel data.\n");

  1376.                 return -1;

  1377.             }

  1378. 

  1379.         memset(reverted_channels, 0, sizeof(*reverted_channels) * avctx->channels);

  1380. 

  1381.         bd.ra_block         = ra_frame;

  1382.         bd.prev_raw_samples = ctx->prev_raw_samples;

  1383. 

  1384.         get_block_sizes(ctx, div_blocks, &bs_info);

  1385. 

  1386.         for (b = 0; b < ctx->num_blocks; b++) {

  1387.             bd.block_length = div_blocks[b];

  1388. 

  1389.             for (c = 0; c < avctx->channels; c++) {

  1390.                 bd.const_block = ctx->const_block + c;

  1391.                 bd.shift_lsbs  = ctx->shift_lsbs + c;

  1392.                 bd.opt_order   = ctx->opt_order + c;

  1393.                 bd.store_prev_samples = ctx->store_prev_samples + c;

  1394.                 bd.use_ltp     = ctx->use_ltp + c;

  1395.                 bd.ltp_lag     = ctx->ltp_lag + c;

  1396.                 bd.ltp_gain    = ctx->ltp_gain[c];

  1397.                 bd.lpc_cof     = ctx->lpc_cof[c];

  1398.                 bd.quant_cof   = ctx->quant_cof[c];

  1399.                 bd.raw_samples = ctx->raw_samples[c] + offset;

  1400.                 bd.raw_other   = NULL;

  1401. 

  1402.                 if ((ret = read_block(ctx, &bd)) < 0)

  1403.                     return ret;

  1404.                 if ((ret = read_channel_data(ctx, ctx->chan_data[c], c)) < 0)

  1405.                     return ret;

  1406.             }

  1407. 

  1408.             for (c = 0; c < avctx->channels; c++)

  1409.                 if (revert_channel_correlation(ctx, &bd, ctx->chan_data,

  1410.                                                reverted_channels, offset, c))

  1411.                     return -1;

  1412. 

  1413.             for (c = 0; c < avctx->channels; c++) {

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

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

  1416.                 bd.opt_order   = ctx->opt_order + c;

  1417.                 bd.store_prev_samples = ctx->store_prev_samples + c;

  1418.                 bd.use_ltp     = ctx->use_ltp + c;

  1419.                 bd.ltp_lag     = ctx->ltp_lag + c;

  1420.                 bd.ltp_gain    = ctx->ltp_gain[c];

  1421.                 bd.lpc_cof     = ctx->lpc_cof[c];

  1422.                 bd.quant_cof   = ctx->quant_cof[c];

  1423.                 bd.raw_samples = ctx->raw_samples[c] + offset;

  1424. 

  1425.                 if ((ret = decode_block(ctx, &bd)) < 0)

  1426.                     return ret;

  1427.             }

  1428. 

  1429.             memset(reverted_channels, 0, avctx->channels * sizeof(*reverted_channels));

  1430.             offset      += div_blocks[b];

  1431.             bd.ra_block  = 0;

  1432.         }

  1433. 

  1434.         // store carryover raw samples

  1435.         for (c = 0; c < avctx->channels; c++)

  1436.             memmove(ctx->raw_samples[c] - sconf->max_order,

  1437.                     ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1438.                     sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1439.     }

  1440. 

  1441.     // TODO: read_diff_float_data

  1442. 

  1443.     return 0;

  1444. }

  1445. 

  1446. 

  1447. /** Decode an ALS frame.

  1448.  */

  1449. static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr,

  1450.                         AVPacket *avpkt)

  1451. {

  1452.     ALSDecContext *ctx       = avctx->priv_data;

  1453.     ALSSpecificConfig *sconf = &ctx->sconf;

  1454.     const uint8_t *buffer    = avpkt->data;

  1455.     int buffer_size          = avpkt->size;

  1456.     int invalid_frame, ret;

  1457.     unsigned int c, sample, ra_frame, bytes_read, shift;

  1458. 

  1459.     init_get_bits(&ctx->gb, buffer, buffer_size * 8);

  1460. 

  1461.     // In the case that the distance between random access frames is set to zero

  1462.     // (sconf->ra_distance == 0) no frame is treated as a random access frame.

  1463.     // For the first frame, if prediction is used, all samples used from the

  1464.     // previous frame are assumed to be zero.

  1465.     ra_frame = sconf->ra_distance && !(ctx->frame_id % sconf->ra_distance);

  1466. 

  1467.     // the last frame to decode might have a different length

  1468.     if (sconf->samples != 0xFFFFFFFF)

  1469.         ctx->cur_frame_length = FFMIN(sconf->samples - ctx->frame_id * (uint64_t) sconf->frame_length,

  1470.                                       sconf->frame_length);

  1471.     else

  1472.         ctx->cur_frame_length = sconf->frame_length;

  1473. 

  1474.     // decode the frame data

  1475.     if ((invalid_frame = read_frame_data(ctx, ra_frame)) < 0)

  1476.         av_log(ctx->avctx, AV_LOG_WARNING,

  1477.                "Reading frame data failed. Skipping RA unit.\n");

  1478. 

  1479.     ctx->frame_id++;

  1480. 

  1481.     /* get output buffer */

  1482.     ctx->frame.nb_samples = ctx->cur_frame_length;

  1483.     if ((ret = ff_get_buffer(avctx, &ctx->frame)) < 0) {

  1484.         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed.\n");

  1485.         return ret;

  1486.     }

  1487. 

  1488.     // transform decoded frame into output format

  1489.     #define INTERLEAVE_OUTPUT(bps)                                                   \

  1490.     {                                                                                \

  1491.         int##bps##_t *dest = (int##bps##_t*)ctx->frame.data[0];                      \

  1492.         shift = bps - ctx->avctx->bits_per_raw_sample;                               \

  1493.         if (!ctx->cs_switch) {                                                       \

  1494.             for (sample = 0; sample < ctx->cur_frame_length; sample++)               \

  1495.                 for (c = 0; c < avctx->channels; c++)                                \

  1496.                     *dest++ = ctx->raw_samples[c][sample] << shift;                  \

  1497.         } else {                                                                     \

  1498.             for (sample = 0; sample < ctx->cur_frame_length; sample++)               \

  1499.                 for (c = 0; c < avctx->channels; c++)                                \

  1500.                     *dest++ = ctx->raw_samples[sconf->chan_pos[c]][sample] << shift; \

  1501.         }                                                                            \

  1502.     }

  1503. 

  1504.     if (ctx->avctx->bits_per_raw_sample <= 16) {

  1505.         INTERLEAVE_OUTPUT(16)

  1506.     } else {

  1507.         INTERLEAVE_OUTPUT(32)

  1508.     }

  1509. 

  1510.     // update CRC

  1511.     if (sconf->crc_enabled && (avctx->err_recognition & (AV_EF_CRCCHECK|AV_EF_CAREFUL))) {

  1512.         int swap = HAVE_BIGENDIAN != sconf->msb_first;

  1513. 

  1514.         if (ctx->avctx->bits_per_raw_sample == 24) {

  1515.             int32_t *src = (int32_t *)ctx->frame.data[0];

  1516. 

  1517.             for (sample = 0;

  1518.                  sample < ctx->cur_frame_length * avctx->channels;

  1519.                  sample++) {

  1520.                 int32_t v;

  1521. 

  1522.                 if (swap)

  1523.                     v = av_bswap32(src[sample]);

  1524.                 else

  1525.                     v = src[sample];

  1526.                 if (!HAVE_BIGENDIAN)

  1527.                     v >>= 8;

  1528. 

  1529.                 ctx->crc = av_crc(ctx->crc_table, ctx->crc, (uint8_t*)(&v), 3);

  1530.             }

  1531.         } else {

  1532.             uint8_t *crc_source;

  1533. 

  1534.             if (swap) {

  1535.                 if (ctx->avctx->bits_per_raw_sample <= 16) {

  1536.                     int16_t *src  = (int16_t*) ctx->frame.data[0];

  1537.                     int16_t *dest = (int16_t*) ctx->crc_buffer;

  1538.                     for (sample = 0;

  1539.                          sample < ctx->cur_frame_length * avctx->channels;

  1540.                          sample++)

  1541.                         *dest++ = av_bswap16(src[sample]);

  1542.                 } else {

  1543.                     ctx->dsp.bswap_buf((uint32_t*)ctx->crc_buffer,

  1544.                                        (uint32_t *)ctx->frame.data[0],

  1545.                                        ctx->cur_frame_length * avctx->channels);

  1546.                 }

  1547.                 crc_source = ctx->crc_buffer;

  1548.             } else {

  1549.                 crc_source = ctx->frame.data[0];

  1550.             }

  1551. 

  1552.             ctx->crc = av_crc(ctx->crc_table, ctx->crc, crc_source,

  1553.                               ctx->cur_frame_length * avctx->channels *

  1554.                               av_get_bytes_per_sample(avctx->sample_fmt));

  1555.         }

  1556. 

  1557. 

  1558.         // check CRC sums if this is the last frame

  1559.         if (ctx->cur_frame_length != sconf->frame_length &&

  1560.             ctx->crc_org != ctx->crc) {

  1561.             av_log(avctx, AV_LOG_ERROR, "CRC error.\n");

  1562.         }

  1563.     }

  1564. 

  1565.     *got_frame_ptr   = 1;

  1566.     *(AVFrame *)data = ctx->frame;

  1567. 

  1568. 

  1569.     bytes_read = invalid_frame ? buffer_size :

  1570.                                  (get_bits_count(&ctx->gb) + 7) >> 3;

  1571. 

  1572.     return bytes_read;

  1573. }

  1574. 

  1575. 

  1576. /** Uninitialize the ALS decoder.

  1577.  */

  1578. static av_cold int decode_end(AVCodecContext *avctx)

  1579. {

  1580.     ALSDecContext *ctx = avctx->priv_data;

  1581. 

  1582.     av_freep(&ctx->sconf.chan_pos);

  1583. 

  1584.     ff_bgmc_end(&ctx->bgmc_lut, &ctx->bgmc_lut_status);

  1585. 

  1586.     av_freep(&ctx->const_block);

  1587.     av_freep(&ctx->shift_lsbs);

  1588.     av_freep(&ctx->opt_order);

  1589.     av_freep(&ctx->store_prev_samples);

  1590.     av_freep(&ctx->use_ltp);

  1591.     av_freep(&ctx->ltp_lag);

  1592.     av_freep(&ctx->ltp_gain);

  1593.     av_freep(&ctx->ltp_gain_buffer);

  1594.     av_freep(&ctx->quant_cof);

  1595.     av_freep(&ctx->lpc_cof);

  1596.     av_freep(&ctx->quant_cof_buffer);

  1597.     av_freep(&ctx->lpc_cof_buffer);

  1598.     av_freep(&ctx->lpc_cof_reversed_buffer);

  1599.     av_freep(&ctx->prev_raw_samples);

  1600.     av_freep(&ctx->raw_samples);

  1601.     av_freep(&ctx->raw_buffer);

  1602.     av_freep(&ctx->chan_data);

  1603.     av_freep(&ctx->chan_data_buffer);

  1604.     av_freep(&ctx->reverted_channels);

  1605.     av_freep(&ctx->crc_buffer);

  1606. 

  1607.     return 0;

  1608. }

  1609. 

  1610. 

  1611. /** Initialize the ALS decoder.

  1612.  */

  1613. static av_cold int decode_init(AVCodecContext *avctx)

  1614. {

  1615.     unsigned int c;

  1616.     unsigned int channel_size;

  1617.     int num_buffers;

  1618.     ALSDecContext *ctx = avctx->priv_data;

  1619.     ALSSpecificConfig *sconf = &ctx->sconf;

  1620.     ctx->avctx = avctx;

  1621. 

  1622.     if (!avctx->extradata) {

  1623.         av_log(avctx, AV_LOG_ERROR, "Missing required ALS extradata.\n");

  1624.         return -1;

  1625.     }

  1626. 

  1627.     if (read_specific_config(ctx)) {

  1628.         av_log(avctx, AV_LOG_ERROR, "Reading ALSSpecificConfig failed.\n");

  1629.         decode_end(avctx);

  1630.         return -1;

  1631.     }

  1632. 

  1633.     if (check_specific_config(ctx)) {

  1634.         decode_end(avctx);

  1635.         return -1;

  1636.     }

  1637. 

  1638.     if (sconf->bgmc)

  1639.         ff_bgmc_init(avctx, &ctx->bgmc_lut, &ctx->bgmc_lut_status);

  1640. 

  1641.     if (sconf->floating) {

  1642.         avctx->sample_fmt          = AV_SAMPLE_FMT_FLT;

  1643.         avctx->bits_per_raw_sample = 32;

  1644.     } else {

  1645.         avctx->sample_fmt          = sconf->resolution > 1

  1646.                                      ? AV_SAMPLE_FMT_S32 : AV_SAMPLE_FMT_S16;

  1647.         avctx->bits_per_raw_sample = (sconf->resolution + 1) * 8;

  1648.     }

  1649. 

  1650.     // set maximum Rice parameter for progressive decoding based on resolution

  1651.     // This is not specified in 14496-3 but actually done by the reference

  1652.     // codec RM22 revision 2.

  1653.     ctx->s_max = sconf->resolution > 1 ? 31 : 15;

  1654. 

  1655.     // set lag value for long-term prediction

  1656.     ctx->ltp_lag_length = 8 + (avctx->sample_rate >=  96000) +

  1657.                               (avctx->sample_rate >= 192000);

  1658. 

  1659.     // allocate quantized parcor coefficient buffer

  1660.     num_buffers = sconf->mc_coding ? avctx->channels : 1;

  1661. 

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

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

  1664.     ctx->quant_cof_buffer = av_malloc(sizeof(*ctx->quant_cof_buffer) *

  1665.                                       num_buffers * sconf->max_order);

  1666.     ctx->lpc_cof_buffer   = av_malloc(sizeof(*ctx->lpc_cof_buffer) *

  1667.                                       num_buffers * sconf->max_order);

  1668.     ctx->lpc_cof_reversed_buffer = av_malloc(sizeof(*ctx->lpc_cof_buffer) *

  1669.                                              sconf->max_order);

  1670. 

  1671.     if (!ctx->quant_cof              || !ctx->lpc_cof        ||

  1672.         !ctx->quant_cof_buffer       || !ctx->lpc_cof_buffer ||

  1673.         !ctx->lpc_cof_reversed_buffer) {

  1674.         av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1675.         return AVERROR(ENOMEM);

  1676.     }

  1677. 

  1678.     // assign quantized parcor coefficient buffers

  1679.     for (c = 0; c < num_buffers; c++) {

  1680.         ctx->quant_cof[c] = ctx->quant_cof_buffer + c * sconf->max_order;

  1681.         ctx->lpc_cof[c]   = ctx->lpc_cof_buffer   + c * sconf->max_order;

  1682.     }

  1683. 

  1684.     // allocate and assign lag and gain data buffer for ltp mode

  1685.     ctx->const_block     = av_malloc (sizeof(*ctx->const_block) * num_buffers);

  1686.     ctx->shift_lsbs      = av_malloc (sizeof(*ctx->shift_lsbs)  * num_buffers);

  1687.     ctx->opt_order       = av_malloc (sizeof(*ctx->opt_order)   * num_buffers);

  1688.     ctx->store_prev_samples = av_malloc(sizeof(*ctx->store_prev_samples) * num_buffers);

  1689.     ctx->use_ltp         = av_mallocz(sizeof(*ctx->use_ltp)  * num_buffers);

  1690.     ctx->ltp_lag         = av_malloc (sizeof(*ctx->ltp_lag)  * num_buffers);

  1691.     ctx->ltp_gain        = av_malloc (sizeof(*ctx->ltp_gain) * num_buffers);

  1692.     ctx->ltp_gain_buffer = av_malloc (sizeof(*ctx->ltp_gain_buffer) *

  1693.                                       num_buffers * 5);

  1694. 

  1695.     if (!ctx->const_block || !ctx->shift_lsbs ||

  1696.         !ctx->opt_order || !ctx->store_prev_samples ||

  1697.         !ctx->use_ltp  || !ctx->ltp_lag ||

  1698.         !ctx->ltp_gain || !ctx->ltp_gain_buffer) {

  1699.         av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1700.         decode_end(avctx);

  1701.         return AVERROR(ENOMEM);

  1702.     }

  1703. 

  1704.     for (c = 0; c < num_buffers; c++)

  1705.         ctx->ltp_gain[c] = ctx->ltp_gain_buffer + c * 5;

  1706. 

  1707.     // allocate and assign channel data buffer for mcc mode

  1708.     if (sconf->mc_coding) {

  1709.         ctx->chan_data_buffer  = av_malloc(sizeof(*ctx->chan_data_buffer) *

  1710.                                            num_buffers * num_buffers);

  1711.         ctx->chan_data         = av_malloc(sizeof(*ctx->chan_data) *

  1712.                                            num_buffers);

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

  1714.                                            num_buffers);

  1715. 

  1716.         if (!ctx->chan_data_buffer || !ctx->chan_data || !ctx->reverted_channels) {

  1717.             av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1718.             decode_end(avctx);

  1719.             return AVERROR(ENOMEM);

  1720.         }

  1721. 

  1722.         for (c = 0; c < num_buffers; c++)

  1723.             ctx->chan_data[c] = ctx->chan_data_buffer + c * num_buffers;

  1724.     } else {

  1725.         ctx->chan_data         = NULL;

  1726.         ctx->chan_data_buffer  = NULL;

  1727.         ctx->reverted_channels = NULL;

  1728.     }

  1729. 

  1730.     channel_size      = sconf->frame_length + sconf->max_order;

  1731. 

  1732.     ctx->prev_raw_samples = av_malloc (sizeof(*ctx->prev_raw_samples) * sconf->max_order);

  1733.     ctx->raw_buffer       = av_mallocz(sizeof(*ctx->     raw_buffer)  * avctx->channels * channel_size);

  1734.     ctx->raw_samples      = av_malloc (sizeof(*ctx->     raw_samples) * avctx->channels);

  1735. 

  1736.     // allocate previous raw sample buffer

  1737.     if (!ctx->prev_raw_samples || !ctx->raw_buffer|| !ctx->raw_samples) {

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

  1739.         decode_end(avctx);

  1740.         return AVERROR(ENOMEM);

  1741.     }

  1742. 

  1743.     // assign raw samples buffers

  1744.     ctx->raw_samples[0] = ctx->raw_buffer + sconf->max_order;

  1745.     for (c = 1; c < avctx->channels; c++)

  1746.         ctx->raw_samples[c] = ctx->raw_samples[c - 1] + channel_size;

  1747. 

  1748.     // allocate crc buffer

  1749.     if (HAVE_BIGENDIAN != sconf->msb_first && sconf->crc_enabled &&

  1750.         (avctx->err_recognition & (AV_EF_CRCCHECK|AV_EF_CAREFUL))) {

  1751.         ctx->crc_buffer = av_malloc(sizeof(*ctx->crc_buffer) *

  1752.                                     ctx->cur_frame_length *

  1753.                                     avctx->channels *

  1754.                                     av_get_bytes_per_sample(avctx->sample_fmt));

  1755.         if (!ctx->crc_buffer) {

  1756.             av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1757.             decode_end(avctx);

  1758.             return AVERROR(ENOMEM);

  1759.         }

  1760.     }

  1761. 

  1762.     ff_dsputil_init(&ctx->dsp, avctx);

  1763. 

  1764.     avcodec_get_frame_defaults(&ctx->frame);

  1765.     avctx->coded_frame = &ctx->frame;

  1766. 

  1767.     return 0;

  1768. }

  1769. 

  1770. 

  1771. /** Flush (reset) the frame ID after seeking.

  1772.  */

  1773. static av_cold void flush(AVCodecContext *avctx)

  1774. {

  1775.     ALSDecContext *ctx = avctx->priv_data;

  1776. 

  1777.     ctx->frame_id = 0;

  1778. }

  1779. 

  1780. 

  1781. AVCodec ff_als_decoder = {

  1782.     .name           = "als",

  1783.     .type           = AVMEDIA_TYPE_AUDIO,

  1784.     .id             = AV_CODEC_ID_MP4ALS,

  1785.     .priv_data_size = sizeof(ALSDecContext),

  1786.     .init           = decode_init,

  1787.     .close          = decode_end,

  1788.     .decode         = decode_frame,

  1789.     .flush          = flush,

  1790.     .capabilities   = CODEC_CAP_SUBFRAMES | CODEC_CAP_DR1,

  1791.     .long_name      = NULL_IF_CONFIG_SMALL("MPEG-4 Audio Lossless Coding (ALS)"),

  1792. };