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FFmpeg/libavcodec/alsdec.c

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  1. /*

  2.  * MPEG-4 ALS decoder

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

  4.  *

  5.  * This file is part of Libav.

  6.  *

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

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

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

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

  11.  *

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

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

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

  15.  * Lesser General Public License for more details.

  16.  *

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

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

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

  20.  */

  21. 

  22. /**

  23.  * @file

  24.  * MPEG-4 ALS decoder

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

  26.  */

  27. 

  28. 

  29. //#define DEBUG

  30. 

  31. 

  32. #include "avcodec.h"

  33. #include "get_bits.h"

  34. #include "unary.h"

  35. #include "mpeg4audio.h"

  36. #include "bytestream.h"

  37. #include "bgmc.h"

  38. #include "dsputil.h"

  39. #include "libavutil/samplefmt.h"

  40. #include "libavutil/crc.h"

  41. 

  42. #include <stdint.h>

  43. 

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

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

  46.  *  by the encoder and stored in ALSSpecificConfig.

  47.  */

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

  49.     { {-52, 4}, {-29, 5}, {-31, 4}, { 19, 4}, {-16, 4},

  50.       { 12, 3}, { -7, 3}, {  9, 3}, { -5, 3}, {  6, 3},

  51.       { -4, 3}, {  3, 3}, { -3, 2}, {  3, 2}, { -2, 2},

  52.       {  3, 2}, { -1, 2}, {  2, 2}, { -1, 2}, {  2, 2} },

  53.     { {-58, 3}, {-42, 4}, {-46, 4}, { 37, 5}, {-36, 4},

  54.       { 29, 4}, {-29, 4}, { 25, 4}, {-23, 4}, { 20, 4},

  55.       {-17, 4}, { 16, 4}, {-12, 4}, { 12, 3}, {-10, 4},

  56.       {  7, 3}, { -4, 4}, {  3, 3}, { -1, 3}, {  1, 3} },

  57.     { {-59, 3}, {-45, 5}, {-50, 4}, { 38, 4}, {-39, 4},

  58.       { 32, 4}, {-30, 4}, { 25, 3}, {-23, 3}, { 20, 3},

  59.       {-20, 3}, { 16, 3}, {-13, 3}, { 10, 3}, { -7, 3},

  60.       {  3, 3}, {  0, 3}, { -1, 3}, {  2, 3}, { -1, 2} }

  61. };

  62. 

  63. 

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

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

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

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

  68.  */

  69. static const int16_t parcor_scaled_values[] = {

  70.     -1048544 / 32, -1048288 / 32, -1047776 / 32, -1047008 / 32,

  71.     -1045984 / 32, -1044704 / 32, -1043168 / 32, -1041376 / 32,

  72.     -1039328 / 32, -1037024 / 32, -1034464 / 32, -1031648 / 32,

  73.     -1028576 / 32, -1025248 / 32, -1021664 / 32, -1017824 / 32,

  74.     -1013728 / 32, -1009376 / 32, -1004768 / 32,  -999904 / 32,

  75.      -994784 / 32,  -989408 / 32,  -983776 / 32,  -977888 / 32,

  76.      -971744 / 32,  -965344 / 32,  -958688 / 32,  -951776 / 32,

  77.      -944608 / 32,  -937184 / 32,  -929504 / 32,  -921568 / 32,

  78.      -913376 / 32,  -904928 / 32,  -896224 / 32,  -887264 / 32,

  79.      -878048 / 32,  -868576 / 32,  -858848 / 32,  -848864 / 32,

  80.      -838624 / 32,  -828128 / 32,  -817376 / 32,  -806368 / 32,

  81.      -795104 / 32,  -783584 / 32,  -771808 / 32,  -759776 / 32,

  82.      -747488 / 32,  -734944 / 32,  -722144 / 32,  -709088 / 32,

  83.      -695776 / 32,  -682208 / 32,  -668384 / 32,  -654304 / 32,

  84.      -639968 / 32,  -625376 / 32,  -610528 / 32,  -595424 / 32,

  85.      -580064 / 32,  -564448 / 32,  -548576 / 32,  -532448 / 32,

  86.      -516064 / 32,  -499424 / 32,  -482528 / 32,  -465376 / 32,

  87.      -447968 / 32,  -430304 / 32,  -412384 / 32,  -394208 / 32,

  88.      -375776 / 32,  -357088 / 32,  -338144 / 32,  -318944 / 32,

  89.      -299488 / 32,  -279776 / 32,  -259808 / 32,  -239584 / 32,

  90.      -219104 / 32,  -198368 / 32,  -177376 / 32,  -156128 / 32,

  91.      -134624 / 32,  -112864 / 32,   -90848 / 32,   -68576 / 32,

  92.       -46048 / 32,   -23264 / 32,     -224 / 32,    23072 / 32,

  93.        46624 / 32,    70432 / 32,    94496 / 32,   118816 / 32,

  94.       143392 / 32,   168224 / 32,   193312 / 32,   218656 / 32,

  95.       244256 / 32,   270112 / 32,   296224 / 32,   322592 / 32,

  96.       349216 / 32,   376096 / 32,   403232 / 32,   430624 / 32,

  97.       458272 / 32,   486176 / 32,   514336 / 32,   542752 / 32,

  98.       571424 / 32,   600352 / 32,   629536 / 32,   658976 / 32,

  99.       688672 / 32,   718624 / 32,   748832 / 32,   779296 / 32,

  100.       810016 / 32,   840992 / 32,   872224 / 32,   903712 / 32,

  101.       935456 / 32,   967456 / 32,   999712 / 32,  1032224 / 32

  102. };

  103. 

  104. 

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

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

  107.  */

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

  109.     { 0,  8, 16,  24},

  110.     {32, 40, 48,  56},

  111.     {64, 70, 76,  82},

  112.     {88, 92, 96, 100}

  113. };

  114. 

  115. 

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

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

  118.  */

  119. static const int16_t mcc_weightings[] = {

  120.     204,  192,  179,  166,  153,  140,  128,  115,

  121.     102,   89,   76,   64,   51,   38,   25,   12,

  122.       0,  -12,  -25,  -38,  -51,  -64,  -76,  -89,

  123.    -102, -115, -128, -140, -153, -166, -179, -192

  124. };

  125. 

  126. 

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

  128.  */

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

  130.     { 74, 44, 25, 13,  7, 3},

  131.     { 68, 42, 24, 13,  7, 3},

  132.     { 58, 39, 23, 13,  7, 3},

  133.     {126, 70, 37, 19, 10, 5},

  134.     {132, 70, 37, 20, 10, 5},

  135.     {124, 70, 38, 20, 10, 5},

  136.     {120, 69, 37, 20, 11, 5},

  137.     {116, 67, 37, 20, 11, 5},

  138.     {108, 66, 36, 20, 10, 5},

  139.     {102, 62, 36, 20, 10, 5},

  140.     { 88, 58, 34, 19, 10, 5},

  141.     {162, 89, 49, 25, 13, 7},

  142.     {156, 87, 49, 26, 14, 7},

  143.     {150, 86, 47, 26, 14, 7},

  144.     {142, 84, 47, 26, 14, 7},

  145.     {131, 79, 46, 26, 14, 7}

  146. };

  147. 

  148. 

  149. enum RA_Flag {

  150.     RA_FLAG_NONE,

  151.     RA_FLAG_FRAMES,

  152.     RA_FLAG_HEADER

  153. };

  154. 

  155. 

  156. typedef struct {

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  179. } ALSSpecificConfig;

  180. 

  181. 

  182. typedef struct {

  183.     int stop_flag;

  184.     int master_channel;

  185.     int time_diff_flag;

  186.     int time_diff_sign;

  187.     int time_diff_index;

  188.     int weighting[6];

  189. } ALSChannelData;

  190. 

  191. 

  192. typedef struct {

  193.     AVCodecContext *avctx;

  194.     AVFrame frame;

  195.     ALSSpecificConfig sconf;

  196.     GetBitContext gb;

  197.     DSPContext dsp;

  198.     const AVCRC *crc_table;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  229. } ALSDecContext;

  230. 

  231. 

  232. typedef struct {

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  248. } ALSBlockData;

  249. 

  250. 

  251. static av_cold void dprint_specific_config(ALSDecContext *ctx)

  252. {

  253. #ifdef DEBUG

  254.     AVCodecContext *avctx    = ctx->avctx;

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

  256. 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  275. #endif

  276. }

  277. 

  278. 

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

  280.  */

  281. static av_cold int read_specific_config(ALSDecContext *ctx)

  282. {

  283.     GetBitContext gb;

  284.     uint64_t ht_size;

  285.     int i, config_offset;

  286.     MPEG4AudioConfig m4ac;

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

  288.     AVCodecContext *avctx    = ctx->avctx;

  289.     uint32_t als_id, header_size, trailer_size;

  290. 

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

  292. 

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

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

  295. 

  296.     if (config_offset < 0)

  297.         return -1;

  298. 

  299.     skip_bits_long(&gb, config_offset);

  300. 

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

  302.         return -1;

  303. 

  304.     // read the fixed items

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

  306.     avctx->sample_rate          = m4ac.sample_rate;

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

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

  309.     avctx->channels             = m4ac.channels;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  333. 

  334. 

  335.     // check for ALSSpecificConfig struct

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

  337.         return -1;

  338. 

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

  340. 

  341.     // read channel config

  342.     if (sconf->chan_config)

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

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

  345. 

  346. 

  347.     // read channel sorting

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

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

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

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

  352.             return -1;

  353. 

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

  355.             return AVERROR(ENOMEM);

  356. 

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

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

  359. 

  360.         align_get_bits(&gb);

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

  362.     } else {

  363.         sconf->chan_sort = 0;

  364.     }

  365. 

  366. 

  367.     // read fixed header and trailer sizes,

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

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

  370.         return -1;

  371. 

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

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

  374.     if (header_size  == 0xFFFFFFFF)

  375.         header_size  = 0;

  376.     if (trailer_size == 0xFFFFFFFF)

  377.         trailer_size = 0;

  378. 

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

  380. 

  381. 

  382.     // skip the header and trailer data

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

  384.         return -1;

  385. 

  386.     if (ht_size > INT32_MAX)

  387.         return -1;

  388. 

  389.     skip_bits_long(&gb, ht_size);

  390. 

  391. 

  392.     // initialize CRC calculation

  393.     if (sconf->crc_enabled) {

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

  395.             return -1;

  396. 

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

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

  399.             ctx->crc       = 0xFFFFFFFF;

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

  401.         } else

  402.             skip_bits_long(&gb, 32);

  403.     }

  404. 

  405. 

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

  407. 

  408.     dprint_specific_config(ctx);

  409. 

  410.     return 0;

  411. }

  412. 

  413. 

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

  415.  */

  416. static int check_specific_config(ALSDecContext *ctx)

  417. {

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

  419.     int error = 0;

  420. 

  421.     // report unsupported feature and set error value

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

  423.     {                                                   \

  424.         if (cond) {                                     \

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

  426.             error = errval;                             \

  427.         }                                               \

  428.     }

  429. 

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

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

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

  433. 

  434.     return error;

  435. }

  436. 

  437. 

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

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

  440.  */

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

  442.                           unsigned int div, unsigned int **div_blocks,

  443.                           unsigned int *num_blocks)

  444. {

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

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

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

  448.         n   *= 2;

  449.         div += 1;

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

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

  452.     } else {

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

  454.         // (bit implicitly not set)

  455.         **div_blocks = div;

  456.         (*div_blocks)++;

  457.         (*num_blocks)++;

  458.     }

  459. }

  460. 

  461. 

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

  463.  */

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

  465. {

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

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

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

  469. 

  470.     if (k > 1) {

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

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

  473.     } else if (!k) {

  474.         q >>= 1;

  475.     }

  476.     return r ? q : ~q;

  477. }

  478. 

  479. 

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

  481.  */

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

  483. {

  484.     int i, j;

  485. 

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

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

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

  489.         cof[i]  += tmp1;

  490.     }

  491.     if (i == j)

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

  493. 

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

  495. }

  496. 

  497. 

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

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

  500.  *  actual number of samples.

  501.  */

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

  503.                             uint32_t *bs_info)

  504. {

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

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

  507.     unsigned int *ptr_div_blocks = div_blocks;

  508.     unsigned int b;

  509. 

  510.     if (sconf->block_switching) {

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

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

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

  514.     }

  515. 

  516.     ctx->num_blocks = 0;

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

  518. 

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

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

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

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

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

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

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

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

  527.     // codec RM22 revision 2.

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

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

  530.     // of 14496-3.

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

  532.     // frame.

  533. 

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

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

  536. 

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

  538.         unsigned int remaining = ctx->cur_frame_length;

  539. 

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

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

  542.                 div_blocks[b] = remaining;

  543.                 ctx->num_blocks = b + 1;

  544.                 break;

  545.             }

  546. 

  547.             remaining -= div_blocks[b];

  548.         }

  549.     }

  550. }

  551. 

  552. 

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

  554.  */

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

  556. {

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

  558.     AVCodecContext *avctx    = ctx->avctx;

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

  560. 

  561.     *bd->raw_samples = 0;

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

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

  564. 

  565.     // skip 5 reserved bits

  566.     skip_bits(gb, 5);

  567. 

  568.     if (*bd->const_block) {

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

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

  571.     }

  572. 

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

  574.     *bd->const_block = 1;

  575. }

  576. 

  577. 

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

  579.  */

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

  581. {

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

  583.     int32_t  val = *bd->raw_samples;

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

  585. 

  586.     // write raw samples into buffer

  587.     for (; smp; smp--)

  588.         *dst++ = val;

  589. }

  590. 

  591. 

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

  593.  */

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

  595. {

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

  597.     AVCodecContext *avctx    = ctx->avctx;

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

  599.     unsigned int k;

  600.     unsigned int s[8];

  601.     unsigned int sx[8];

  602.     unsigned int sub_blocks, log2_sub_blocks, sb_length;

  603.     unsigned int start      = 0;

  604.     unsigned int opt_order;

  605.     int          sb;

  606.     int32_t      *quant_cof = bd->quant_cof;

  607.     int32_t      *current_res;

  608. 

  609. 

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

  611.     *bd->const_block = 0;

  612. 

  613.     *bd->opt_order  = 1;

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

  615. 

  616.     opt_order       = *bd->opt_order;

  617. 

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

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

  620.         log2_sub_blocks = 0;

  621.     } else {

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

  623.             log2_sub_blocks = get_bits(gb, 2);

  624.         else

  625.             log2_sub_blocks = 2 * get_bits1(gb);

  626.     }

  627. 

  628.     sub_blocks = 1 << log2_sub_blocks;

  629. 

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

  631.     // block_length must be evenly divisible by sub_blocks

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

  633.         av_log(avctx, AV_LOG_WARNING,

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

  635.         return -1;

  636.     }

  637. 

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

  639. 

  640.     if (sconf->bgmc) {

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

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

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

  644. 

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

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

  647.             s [k] >>= 4;

  648.         }

  649.     } else {

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

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

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

  653.     }

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

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

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

  657.             return AVERROR_INVALIDDATA;

  658.         }

  659. 

  660.     if (get_bits1(gb))

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

  662. 

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

  664. 

  665. 

  666.     if (!sconf->rlslms) {

  667.         if (sconf->adapt_order) {

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

  669.                                                 2, sconf->max_order + 1));

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

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

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

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

  674.                 return AVERROR_INVALIDDATA;

  675.             }

  676.         } else {

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

  678.         }

  679. 

  680.         opt_order = *bd->opt_order;

  681. 

  682.         if (opt_order) {

  683.             int add_base;

  684. 

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

  686.                 add_base = 0x7F;

  687. 

  688.                 // read coefficient 0

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

  690. 

  691.                 // read coefficient 1

  692.                 if (opt_order > 1)

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

  694. 

  695.                 // read coefficients 2 to opt_order

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

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

  698.             } else {

  699.                 int k_max;

  700.                 add_base = 1;

  701. 

  702.                 // read coefficient 0 to 19

  703.                 k_max = FFMIN(opt_order, 20);

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

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

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

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

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

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

  710.                         return AVERROR_INVALIDDATA;

  711.                     }

  712.                 }

  713. 

  714.                 // read coefficients 20 to 126

  715.                 k_max = FFMIN(opt_order, 127);

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

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

  718. 

  719.                 // read coefficients 127 to opt_order

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

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

  722. 

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

  724. 

  725.                 if (opt_order > 1)

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

  727.             }

  728. 

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

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

  731.         }

  732.     }

  733. 

  734.     // read LTP gain and lag values

  735.     if (sconf->long_term_prediction) {

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

  737. 

  738.         if (*bd->use_ltp) {

  739.             int r, c;

  740. 

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

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

  743. 

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

  745.             c                 = get_bits(gb, 2);

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

  747. 

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

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

  750. 

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

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

  753.         }

  754.     }

  755. 

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

  757.     if (bd->ra_block) {

  758.         if (opt_order)

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

  760.         if (opt_order > 1)

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

  762.         if (opt_order > 2)

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

  764. 

  765.         start = FFMIN(opt_order, 3);

  766.     }

  767. 

  768.     // read all residuals

  769.     if (sconf->bgmc) {

  770.         int          delta[8];

  771.         unsigned int k    [8];

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

  773. 

  774.         // read most significant bits

  775.         unsigned int high;

  776.         unsigned int low;

  777.         unsigned int value;

  778. 

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

  780. 

  781.         current_res = bd->raw_samples + start;

  782. 

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

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

  785. 

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

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

  788. 

  789.             ff_bgmc_decode(gb, sb_len, current_res,

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

  791. 

  792.             current_res += sb_len;

  793.         }

  794. 

  795.         ff_bgmc_decode_end(gb);

  796. 

  797. 

  798.         // read least significant bits and tails

  799.         current_res = bd->raw_samples + start;

  800. 

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

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

  803.             unsigned int cur_k         = k[sb];

  804.             unsigned int cur_s         = s[sb];

  805. 

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

  807.                 int32_t res = *current_res;

  808. 

  809.                 if (res == cur_tail_code) {

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

  811.                                           << (5 - delta[sb]);

  812. 

  813.                     res = decode_rice(gb, cur_s);

  814. 

  815.                     if (res >= 0) {

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

  817.                     } else {

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

  819.                     }

  820.                 } else {

  821.                     if (res > cur_tail_code)

  822.                         res--;

  823. 

  824.                     if (res & 1)

  825.                         res = -res;

  826. 

  827.                     res >>= 1;

  828. 

  829.                     if (cur_k) {

  830.                         res <<= cur_k;

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

  832.                     }

  833.                 }

  834. 

  835.                 *current_res++ = res;

  836.             }

  837.         }

  838.     } else {

  839.         current_res = bd->raw_samples + start;

  840. 

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

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

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

  844.      }

  845. 

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

  847.         align_get_bits(gb);

  848. 

  849.     return 0;

  850. }

  851. 

  852. 

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

  854.  */

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

  856. {

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

  858.     unsigned int block_length = bd->block_length;

  859.     unsigned int smp = 0;

  860.     unsigned int k;

  861.     int opt_order             = *bd->opt_order;

  862.     int sb;

  863.     int64_t y;

  864.     int32_t *quant_cof        = bd->quant_cof;

  865.     int32_t *lpc_cof          = bd->lpc_cof;

  866.     int32_t *raw_samples      = bd->raw_samples;

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

  868.     int32_t *lpc_cof_reversed = ctx->lpc_cof_reversed_buffer;

  869. 

  870.     // reverse long-term prediction

  871.     if (*bd->use_ltp) {

  872.         int ltp_smp;

  873. 

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

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

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

  877.             int end    = center + 3;

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

  879.             int base;

  880. 

  881.             y = 1 << 6;

  882. 

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

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

  885. 

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

  887.         }

  888.     }

  889. 

  890.     // reconstruct all samples from residuals

  891.     if (bd->ra_block) {

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

  893.             y = 1 << 19;

  894. 

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

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

  897. 

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

  899.             parcor_to_lpc(smp, quant_cof, lpc_cof);

  900.         }

  901.     } else {

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

  903.             parcor_to_lpc(k, quant_cof, lpc_cof);

  904. 

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

  906.         if (*bd->store_prev_samples)

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

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

  909. 

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

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

  912.             int32_t *left, *right;

  913. 

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

  915.                 left  = raw_samples;

  916.                 right = bd->raw_other;

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

  918.                 left  = bd->raw_other;

  919.                 right = raw_samples;

  920.             }

  921. 

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

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

  924.         }

  925. 

  926.         // reconstruct shifted signal

  927.         if (*bd->shift_lsbs)

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

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

  930.     }

  931. 

  932.     // reverse linear prediction coefficients for efficiency

  933.     lpc_cof = lpc_cof + opt_order;

  934. 

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

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

  937. 

  938.     // reconstruct raw samples

  939.     raw_samples = bd->raw_samples + smp;

  940.     lpc_cof     = lpc_cof_reversed + opt_order;

  941. 

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

  943.         y = 1 << 19;

  944. 

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

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

  947. 

  948.         *raw_samples -= y >> 20;

  949.     }

  950. 

  951.     raw_samples = bd->raw_samples;

  952. 

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

  954.     if (*bd->store_prev_samples)

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

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

  957. 

  958.     return 0;

  959. }

  960. 

  961. 

  962. /** Read the block data.

  963.  */

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

  965. {

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

  967. 

  968.     *bd->shift_lsbs = 0;

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

  970.     if (get_bits1(gb)) {

  971.         if (read_var_block_data(ctx, bd))

  972.             return -1;

  973.     } else {

  974.         read_const_block_data(ctx, bd);

  975.     }

  976. 

  977.     return 0;

  978. }

  979. 

  980. 

  981. /** Decode the block data.

  982.  */

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

  984. {

  985.     unsigned int smp;

  986. 

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

  988.     if (*bd->const_block)

  989.         decode_const_block_data(ctx, bd);

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

  991.         return -1;

  992. 

  993.     // TODO: read RLSLMS extension data

  994. 

  995.     if (*bd->shift_lsbs)

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

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

  998. 

  999.     return 0;

  1000. }

  1001. 

  1002. 

  1003. /** Read and decode block data successively.

  1004.  */

  1005. static int read_decode_block(ALSDecContext *ctx, ALSBlockData *bd)

  1006. {

  1007.     int ret;

  1008. 

  1009.     ret = read_block(ctx, bd);

  1010. 

  1011.     if (ret)

  1012.         return ret;

  1013. 

  1014.     ret = decode_block(ctx, bd);

  1015. 

  1016.     return ret;

  1017. }

  1018. 

  1019. 

  1020. /** Compute the number of samples left to decode for the current frame and

  1021.  *  sets these samples to zero.

  1022.  */

  1023. static void zero_remaining(unsigned int b, unsigned int b_max,

  1024.                            const unsigned int *div_blocks, int32_t *buf)

  1025. {

  1026.     unsigned int count = 0;

  1027. 

  1028.     for (; b < b_max; b++)

  1029.         count += div_blocks[b];

  1030. 

  1031.     if (count)

  1032.         memset(buf, 0, sizeof(*buf) * count);

  1033. }

  1034. 

  1035. 

  1036. /** Decode blocks independently.

  1037.  */

  1038. static int decode_blocks_ind(ALSDecContext *ctx, unsigned int ra_frame,

  1039.                              unsigned int c, const unsigned int *div_blocks,

  1040.                              unsigned int *js_blocks)

  1041. {

  1042.     unsigned int b;

  1043.     ALSBlockData bd = { 0 };

  1044. 

  1045.     bd.ra_block         = ra_frame;

  1046.     bd.const_block      = ctx->const_block;

  1047.     bd.shift_lsbs       = ctx->shift_lsbs;

  1048.     bd.opt_order        = ctx->opt_order;

  1049.     bd.store_prev_samples = ctx->store_prev_samples;

  1050.     bd.use_ltp          = ctx->use_ltp;

  1051.     bd.ltp_lag          = ctx->ltp_lag;

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

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

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

  1055.     bd.prev_raw_samples = ctx->prev_raw_samples;

  1056.     bd.raw_samples      = ctx->raw_samples[c];

  1057. 

  1058. 

  1059.     for (b = 0; b < ctx->num_blocks; b++) {

  1060.         bd.block_length     = div_blocks[b];

  1061. 

  1062.         if (read_decode_block(ctx, &bd)) {

  1063.             // damaged block, write zero for the rest of the frame

  1064.             zero_remaining(b, ctx->num_blocks, div_blocks, bd.raw_samples);

  1065.             return -1;

  1066.         }

  1067.         bd.raw_samples += div_blocks[b];

  1068.         bd.ra_block     = 0;

  1069.     }

  1070. 

  1071.     return 0;

  1072. }

  1073. 

  1074. 

  1075. /** Decode blocks dependently.

  1076.  */

  1077. static int decode_blocks(ALSDecContext *ctx, unsigned int ra_frame,

  1078.                          unsigned int c, const unsigned int *div_blocks,

  1079.                          unsigned int *js_blocks)

  1080. {

  1081.     ALSSpecificConfig *sconf = &ctx->sconf;

  1082.     unsigned int offset = 0;

  1083.     unsigned int b;

  1084.     ALSBlockData bd[2] = { { 0 } };

  1085. 

  1086.     bd[0].ra_block         = ra_frame;

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

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

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

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

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

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

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

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

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

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

  1097.     bd[0].js_blocks        = *js_blocks;

  1098. 

  1099.     bd[1].ra_block         = ra_frame;

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

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

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

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

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

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

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

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

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

  1109.     bd[1].prev_raw_samples = ctx->prev_raw_samples;

  1110.     bd[1].js_blocks        = *(js_blocks + 1);

  1111. 

  1112.     // decode all blocks

  1113.     for (b = 0; b < ctx->num_blocks; b++) {

  1114.         unsigned int s;

  1115. 

  1116.         bd[0].block_length = div_blocks[b];

  1117.         bd[1].block_length = div_blocks[b];

  1118. 

  1119.         bd[0].raw_samples  = ctx->raw_samples[c    ] + offset;

  1120.         bd[1].raw_samples  = ctx->raw_samples[c + 1] + offset;

  1121. 

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

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

  1124. 

  1125.         if(read_decode_block(ctx, &bd[0]) || read_decode_block(ctx, &bd[1])) {

  1126.             // damaged block, write zero for the rest of the frame

  1127.             zero_remaining(b, ctx->num_blocks, div_blocks, bd[0].raw_samples);

  1128.             zero_remaining(b, ctx->num_blocks, div_blocks, bd[1].raw_samples);

  1129.             return -1;

  1130.         }

  1131. 

  1132.         // reconstruct joint-stereo blocks

  1133.         if (bd[0].js_blocks) {

  1134.             if (bd[1].js_blocks)

  1135.                 av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel pair!\n");

  1136. 

  1137.             for (s = 0; s < div_blocks[b]; s++)

  1138.                 bd[0].raw_samples[s] = bd[1].raw_samples[s] - bd[0].raw_samples[s];

  1139.         } else if (bd[1].js_blocks) {

  1140.             for (s = 0; s < div_blocks[b]; s++)

  1141.                 bd[1].raw_samples[s] = bd[1].raw_samples[s] + bd[0].raw_samples[s];

  1142.         }

  1143. 

  1144.         offset  += div_blocks[b];

  1145.         bd[0].ra_block = 0;

  1146.         bd[1].ra_block = 0;

  1147.     }

  1148. 

  1149.     // store carryover raw samples,

  1150.     // the others channel raw samples are stored by the calling function.

  1151.     memmove(ctx->raw_samples[c] - sconf->max_order,

  1152.             ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1153.             sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1154. 

  1155.     return 0;

  1156. }

  1157. 

  1158. 

  1159. /** Read the channel data.

  1160.   */

  1161. static int read_channel_data(ALSDecContext *ctx, ALSChannelData *cd, int c)

  1162. {

  1163.     GetBitContext *gb       = &ctx->gb;

  1164.     ALSChannelData *current = cd;

  1165.     unsigned int channels   = ctx->avctx->channels;

  1166.     int entries             = 0;

  1167. 

  1168.     while (entries < channels && !(current->stop_flag = get_bits1(gb))) {

  1169.         current->master_channel = get_bits_long(gb, av_ceil_log2(channels));

  1170. 

  1171.         if (current->master_channel >= channels) {

  1172.             av_log(ctx->avctx, AV_LOG_ERROR, "Invalid master channel!\n");

  1173.             return -1;

  1174.         }

  1175. 

  1176.         if (current->master_channel != c) {

  1177.             current->time_diff_flag = get_bits1(gb);

  1178.             current->weighting[0]   = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 32)];

  1179.             current->weighting[1]   = mcc_weightings[av_clip(decode_rice(gb, 2) + 14, 0, 32)];

  1180.             current->weighting[2]   = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 32)];

  1181. 

  1182.             if (current->time_diff_flag) {

  1183.                 current->weighting[3] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 32)];

  1184.                 current->weighting[4] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 32)];

  1185.                 current->weighting[5] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 32)];

  1186. 

  1187.                 current->time_diff_sign  = get_bits1(gb);

  1188.                 current->time_diff_index = get_bits(gb, ctx->ltp_lag_length - 3) + 3;

  1189.             }

  1190.         }

  1191. 

  1192.         current++;

  1193.         entries++;

  1194.     }

  1195. 

  1196.     if (entries == channels) {

  1197.         av_log(ctx->avctx, AV_LOG_ERROR, "Damaged channel data!\n");

  1198.         return -1;

  1199.     }

  1200. 

  1201.     align_get_bits(gb);

  1202.     return 0;

  1203. }

  1204. 

  1205. 

  1206. /** Recursively reverts the inter-channel correlation for a block.

  1207.  */

  1208. static int revert_channel_correlation(ALSDecContext *ctx, ALSBlockData *bd,

  1209.                                        ALSChannelData **cd, int *reverted,

  1210.                                        unsigned int offset, int c)

  1211. {

  1212.     ALSChannelData *ch = cd[c];

  1213.     unsigned int   dep = 0;

  1214.     unsigned int channels = ctx->avctx->channels;

  1215. 

  1216.     if (reverted[c])

  1217.         return 0;

  1218. 

  1219.     reverted[c] = 1;

  1220. 

  1221.     while (dep < channels && !ch[dep].stop_flag) {

  1222.         revert_channel_correlation(ctx, bd, cd, reverted, offset,

  1223.                                    ch[dep].master_channel);

  1224. 

  1225.         dep++;

  1226.     }

  1227. 

  1228.     if (dep == channels) {

  1229.         av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel correlation!\n");

  1230.         return -1;

  1231.     }

  1232. 

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

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

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

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

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

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

  1239.     bd->ltp_gain    = ctx->ltp_gain[c];

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

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

  1242.     bd->raw_samples = ctx->raw_samples[c] + offset;

  1243. 

  1244.     dep = 0;

  1245.     while (!ch[dep].stop_flag) {

  1246.         unsigned int smp;

  1247.         unsigned int begin = 1;

  1248.         unsigned int end   = bd->block_length - 1;

  1249.         int64_t y;

  1250.         int32_t *master = ctx->raw_samples[ch[dep].master_channel] + offset;

  1251. 

  1252.         if (ch[dep].time_diff_flag) {

  1253.             int t = ch[dep].time_diff_index;

  1254. 

  1255.             if (ch[dep].time_diff_sign) {

  1256.                 t      = -t;

  1257.                 begin -= t;

  1258.             } else {

  1259.                 end   -= t;

  1260.             }

  1261. 

  1262.             for (smp = begin; smp < end; smp++) {

  1263.                 y  = (1 << 6) +

  1264.                      MUL64(ch[dep].weighting[0], master[smp - 1    ]) +

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

  1266.                      MUL64(ch[dep].weighting[2], master[smp + 1    ]) +

  1267.                      MUL64(ch[dep].weighting[3], master[smp - 1 + t]) +

  1268.                      MUL64(ch[dep].weighting[4], master[smp     + t]) +

  1269.                      MUL64(ch[dep].weighting[5], master[smp + 1 + t]);

  1270. 

  1271.                 bd->raw_samples[smp] += y >> 7;

  1272.             }

  1273.         } else {

  1274.             for (smp = begin; smp < end; smp++) {

  1275.                 y  = (1 << 6) +

  1276.                      MUL64(ch[dep].weighting[0], master[smp - 1]) +

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

  1278.                      MUL64(ch[dep].weighting[2], master[smp + 1]);

  1279. 

  1280.                 bd->raw_samples[smp] += y >> 7;

  1281.             }

  1282.         }

  1283. 

  1284.         dep++;

  1285.     }

  1286. 

  1287.     return 0;

  1288. }

  1289. 

  1290. 

  1291. /** Read the frame data.

  1292.  */

  1293. static int read_frame_data(ALSDecContext *ctx, unsigned int ra_frame)

  1294. {

  1295.     ALSSpecificConfig *sconf = &ctx->sconf;

  1296.     AVCodecContext *avctx    = ctx->avctx;

  1297.     GetBitContext *gb = &ctx->gb;

  1298.     unsigned int div_blocks[32];                ///< block sizes.

  1299.     unsigned int c;

  1300.     unsigned int js_blocks[2];

  1301. 

  1302.     uint32_t bs_info = 0;

  1303. 

  1304.     // skip the size of the ra unit if present in the frame

  1305.     if (sconf->ra_flag == RA_FLAG_FRAMES && ra_frame)

  1306.         skip_bits_long(gb, 32);

  1307. 

  1308.     if (sconf->mc_coding && sconf->joint_stereo) {

  1309.         ctx->js_switch = get_bits1(gb);

  1310.         align_get_bits(gb);

  1311.     }

  1312. 

  1313.     if (!sconf->mc_coding || ctx->js_switch) {

  1314.         int independent_bs = !sconf->joint_stereo;

  1315. 

  1316.         for (c = 0; c < avctx->channels; c++) {

  1317.             js_blocks[0] = 0;

  1318.             js_blocks[1] = 0;

  1319. 

  1320.             get_block_sizes(ctx, div_blocks, &bs_info);

  1321. 

  1322.             // if joint_stereo and block_switching is set, independent decoding

  1323.             // is signaled via the first bit of bs_info

  1324.             if (sconf->joint_stereo && sconf->block_switching)

  1325.                 if (bs_info >> 31)

  1326.                     independent_bs = 2;

  1327. 

  1328.             // if this is the last channel, it has to be decoded independently

  1329.             if (c == avctx->channels - 1)

  1330.                 independent_bs = 1;

  1331. 

  1332.             if (independent_bs) {

  1333.                 if (decode_blocks_ind(ctx, ra_frame, c, div_blocks, js_blocks))

  1334.                     return -1;

  1335. 

  1336.                 independent_bs--;

  1337.             } else {

  1338.                 if (decode_blocks(ctx, ra_frame, c, div_blocks, js_blocks))

  1339.                     return -1;

  1340. 

  1341.                 c++;

  1342.             }

  1343. 

  1344.             // store carryover raw samples

  1345.             memmove(ctx->raw_samples[c] - sconf->max_order,

  1346.                     ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1347.                     sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1348.         }

  1349.     } else { // multi-channel coding

  1350.         ALSBlockData   bd = { 0 };

  1351.         int            b, ret;

  1352.         int            *reverted_channels = ctx->reverted_channels;

  1353.         unsigned int   offset             = 0;

  1354. 

  1355.         for (c = 0; c < avctx->channels; c++)

  1356.             if (ctx->chan_data[c] < ctx->chan_data_buffer) {

  1357.                 av_log(ctx->avctx, AV_LOG_ERROR, "Invalid channel data!\n");

  1358.                 return -1;

  1359.             }

  1360. 

  1361.         memset(reverted_channels, 0, sizeof(*reverted_channels) * avctx->channels);

  1362. 

  1363.         bd.ra_block         = ra_frame;

  1364.         bd.prev_raw_samples = ctx->prev_raw_samples;

  1365. 

  1366.         get_block_sizes(ctx, div_blocks, &bs_info);

  1367. 

  1368.         for (b = 0; b < ctx->num_blocks; b++) {

  1369.             bd.block_length = div_blocks[b];

  1370. 

  1371.             for (c = 0; c < avctx->channels; c++) {

  1372.                 bd.const_block = ctx->const_block + c;

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

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

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

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

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

  1378.                 bd.ltp_gain    = ctx->ltp_gain[c];

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

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

  1381.                 bd.raw_samples = ctx->raw_samples[c] + offset;

  1382.                 bd.raw_other   = NULL;

  1383. 

  1384.                 if ((ret = read_block(ctx, &bd)) < 0)

  1385.                     return ret;

  1386.                 if ((ret = read_channel_data(ctx, ctx->chan_data[c], c)) < 0)

  1387.                     return ret;

  1388.             }

  1389. 

  1390.             for (c = 0; c < avctx->channels; c++)

  1391.                 if (revert_channel_correlation(ctx, &bd, ctx->chan_data,

  1392.                                                reverted_channels, offset, c))

  1393.                     return -1;

  1394. 

  1395.             for (c = 0; c < avctx->channels; c++) {

  1396.                 bd.const_block = ctx->const_block + c;

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

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

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

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

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

  1402.                 bd.ltp_gain    = ctx->ltp_gain[c];

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

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

  1405.                 bd.raw_samples = ctx->raw_samples[c] + offset;

  1406.                 if ((ret = decode_block(ctx, &bd)) < 0)

  1407.                     return ret;

  1408.             }

  1409. 

  1410.             memset(reverted_channels, 0, avctx->channels * sizeof(*reverted_channels));

  1411.             offset      += div_blocks[b];

  1412.             bd.ra_block  = 0;

  1413.         }

  1414. 

  1415.         // store carryover raw samples

  1416.         for (c = 0; c < avctx->channels; c++)

  1417.             memmove(ctx->raw_samples[c] - sconf->max_order,

  1418.                     ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1419.                     sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1420.     }

  1421. 

  1422.     // TODO: read_diff_float_data

  1423. 

  1424.     return 0;

  1425. }

  1426. 

  1427. 

  1428. /** Decode an ALS frame.

  1429.  */

  1430. static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr,

  1431.                         AVPacket *avpkt)

  1432. {

  1433.     ALSDecContext *ctx       = avctx->priv_data;

  1434.     ALSSpecificConfig *sconf = &ctx->sconf;

  1435.     const uint8_t *buffer    = avpkt->data;

  1436.     int buffer_size          = avpkt->size;

  1437.     int invalid_frame, ret;

  1438.     unsigned int c, sample, ra_frame, bytes_read, shift;

  1439. 

  1440.     init_get_bits(&ctx->gb, buffer, buffer_size * 8);

  1441. 

  1442.     // In the case that the distance between random access frames is set to zero

  1443.     // (sconf->ra_distance == 0) no frame is treated as a random access frame.

  1444.     // For the first frame, if prediction is used, all samples used from the

  1445.     // previous frame are assumed to be zero.

  1446.     ra_frame = sconf->ra_distance && !(ctx->frame_id % sconf->ra_distance);

  1447. 

  1448.     // the last frame to decode might have a different length

  1449.     if (sconf->samples != 0xFFFFFFFF)

  1450.         ctx->cur_frame_length = FFMIN(sconf->samples - ctx->frame_id * (uint64_t) sconf->frame_length,

  1451.                                       sconf->frame_length);

  1452.     else

  1453.         ctx->cur_frame_length = sconf->frame_length;

  1454. 

  1455.     // decode the frame data

  1456.     if ((invalid_frame = read_frame_data(ctx, ra_frame)) < 0)

  1457.         av_log(ctx->avctx, AV_LOG_WARNING,

  1458.                "Reading frame data failed. Skipping RA unit.\n");

  1459. 

  1460.     ctx->frame_id++;

  1461. 

  1462.     /* get output buffer */

  1463.     ctx->frame.nb_samples = ctx->cur_frame_length;

  1464.     if ((ret = avctx->get_buffer(avctx, &ctx->frame)) < 0) {

  1465.         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");

  1466.         return ret;

  1467.     }

  1468. 

  1469.     // transform decoded frame into output format

  1470.     #define INTERLEAVE_OUTPUT(bps)                                 \

  1471.     {                                                              \

  1472.         int##bps##_t *dest = (int##bps##_t*)ctx->frame.data[0];    \

  1473.         shift = bps - ctx->avctx->bits_per_raw_sample;             \

  1474.         for (sample = 0; sample < ctx->cur_frame_length; sample++) \

  1475.             for (c = 0; c < avctx->channels; c++)                  \

  1476.                 *dest++ = ctx->raw_samples[c][sample] << shift;    \

  1477.     }

  1478. 

  1479.     if (ctx->avctx->bits_per_raw_sample <= 16) {

  1480.         INTERLEAVE_OUTPUT(16)

  1481.     } else {

  1482.         INTERLEAVE_OUTPUT(32)

  1483.     }

  1484. 

  1485.     // update CRC

  1486.     if (sconf->crc_enabled && (avctx->err_recognition & AV_EF_CRCCHECK)) {

  1487.         int swap = HAVE_BIGENDIAN != sconf->msb_first;

  1488. 

  1489.         if (ctx->avctx->bits_per_raw_sample == 24) {

  1490.             int32_t *src = (int32_t *)ctx->frame.data[0];

  1491. 

  1492.             for (sample = 0;

  1493.                  sample < ctx->cur_frame_length * avctx->channels;

  1494.                  sample++) {

  1495.                 int32_t v;

  1496. 

  1497.                 if (swap)

  1498.                     v = av_bswap32(src[sample]);

  1499.                 else

  1500.                     v = src[sample];

  1501.                 if (!HAVE_BIGENDIAN)

  1502.                     v >>= 8;

  1503. 

  1504.                 ctx->crc = av_crc(ctx->crc_table, ctx->crc, (uint8_t*)(&v), 3);

  1505.             }

  1506.         } else {

  1507.             uint8_t *crc_source;

  1508. 

  1509.             if (swap) {

  1510.                 if (ctx->avctx->bits_per_raw_sample <= 16) {

  1511.                     int16_t *src  = (int16_t*) ctx->frame.data[0];

  1512.                     int16_t *dest = (int16_t*) ctx->crc_buffer;

  1513.                     for (sample = 0;

  1514.                          sample < ctx->cur_frame_length * avctx->channels;

  1515.                          sample++)

  1516.                         *dest++ = av_bswap16(src[sample]);

  1517.                 } else {

  1518.                     ctx->dsp.bswap_buf((uint32_t*)ctx->crc_buffer,

  1519.                                        (uint32_t *)ctx->frame.data[0],

  1520.                                        ctx->cur_frame_length * avctx->channels);

  1521.                 }

  1522.                 crc_source = ctx->crc_buffer;

  1523.             } else {

  1524.                 crc_source = ctx->frame.data[0];

  1525.             }

  1526. 

  1527.             ctx->crc = av_crc(ctx->crc_table, ctx->crc, crc_source,

  1528.                               ctx->cur_frame_length * avctx->channels *

  1529.                               av_get_bytes_per_sample(avctx->sample_fmt));

  1530.         }

  1531. 

  1532. 

  1533.         // check CRC sums if this is the last frame

  1534.         if (ctx->cur_frame_length != sconf->frame_length &&

  1535.             ctx->crc_org != ctx->crc) {

  1536.             av_log(avctx, AV_LOG_ERROR, "CRC error.\n");

  1537.         }

  1538.     }

  1539. 

  1540.     *got_frame_ptr   = 1;

  1541.     *(AVFrame *)data = ctx->frame;

  1542. 

  1543. 

  1544.     bytes_read = invalid_frame ? buffer_size :

  1545.                                  (get_bits_count(&ctx->gb) + 7) >> 3;

  1546. 

  1547.     return bytes_read;

  1548. }

  1549. 

  1550. 

  1551. /** Uninitialize the ALS decoder.

  1552.  */

  1553. static av_cold int decode_end(AVCodecContext *avctx)

  1554. {

  1555.     ALSDecContext *ctx = avctx->priv_data;

  1556. 

  1557.     av_freep(&ctx->sconf.chan_pos);

  1558. 

  1559.     ff_bgmc_end(&ctx->bgmc_lut, &ctx->bgmc_lut_status);

  1560. 

  1561.     av_freep(&ctx->const_block);

  1562.     av_freep(&ctx->shift_lsbs);

  1563.     av_freep(&ctx->opt_order);

  1564.     av_freep(&ctx->store_prev_samples);

  1565.     av_freep(&ctx->use_ltp);

  1566.     av_freep(&ctx->ltp_lag);

  1567.     av_freep(&ctx->ltp_gain);

  1568.     av_freep(&ctx->ltp_gain_buffer);

  1569.     av_freep(&ctx->quant_cof);

  1570.     av_freep(&ctx->lpc_cof);

  1571.     av_freep(&ctx->quant_cof_buffer);

  1572.     av_freep(&ctx->lpc_cof_buffer);

  1573.     av_freep(&ctx->lpc_cof_reversed_buffer);

  1574.     av_freep(&ctx->prev_raw_samples);

  1575.     av_freep(&ctx->raw_samples);

  1576.     av_freep(&ctx->raw_buffer);

  1577.     av_freep(&ctx->chan_data);

  1578.     av_freep(&ctx->chan_data_buffer);

  1579.     av_freep(&ctx->reverted_channels);

  1580.     av_freep(&ctx->crc_buffer);

  1581. 

  1582.     return 0;

  1583. }

  1584. 

  1585. 

  1586. /** Initialize the ALS decoder.

  1587.  */

  1588. static av_cold int decode_init(AVCodecContext *avctx)

  1589. {

  1590.     unsigned int c;

  1591.     unsigned int channel_size;

  1592.     int num_buffers;

  1593.     ALSDecContext *ctx = avctx->priv_data;

  1594.     ALSSpecificConfig *sconf = &ctx->sconf;

  1595.     ctx->avctx = avctx;

  1596. 

  1597.     if (!avctx->extradata) {

  1598.         av_log(avctx, AV_LOG_ERROR, "Missing required ALS extradata.\n");

  1599.         return -1;

  1600.     }

  1601. 

  1602.     if (read_specific_config(ctx)) {

  1603.         av_log(avctx, AV_LOG_ERROR, "Reading ALSSpecificConfig failed.\n");

  1604.         decode_end(avctx);

  1605.         return -1;

  1606.     }

  1607. 

  1608.     if (check_specific_config(ctx)) {

  1609.         decode_end(avctx);

  1610.         return -1;

  1611.     }

  1612. 

  1613.     if (sconf->bgmc)

  1614.         ff_bgmc_init(avctx, &ctx->bgmc_lut, &ctx->bgmc_lut_status);

  1615. 

  1616.     if (sconf->floating) {

  1617.         avctx->sample_fmt          = AV_SAMPLE_FMT_FLT;

  1618.         avctx->bits_per_raw_sample = 32;

  1619.     } else {

  1620.         avctx->sample_fmt          = sconf->resolution > 1

  1621.                                      ? AV_SAMPLE_FMT_S32 : AV_SAMPLE_FMT_S16;

  1622.         avctx->bits_per_raw_sample = (sconf->resolution + 1) * 8;

  1623.     }

  1624. 

  1625.     // set maximum Rice parameter for progressive decoding based on resolution

  1626.     // This is not specified in 14496-3 but actually done by the reference

  1627.     // codec RM22 revision 2.

  1628.     ctx->s_max = sconf->resolution > 1 ? 31 : 15;

  1629. 

  1630.     // set lag value for long-term prediction

  1631.     ctx->ltp_lag_length = 8 + (avctx->sample_rate >=  96000) +

  1632.                               (avctx->sample_rate >= 192000);

  1633. 

  1634.     // allocate quantized parcor coefficient buffer

  1635.     num_buffers = sconf->mc_coding ? avctx->channels : 1;

  1636. 

  1637.     ctx->quant_cof        = av_malloc(sizeof(*ctx->quant_cof) * num_buffers);

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

  1639.     ctx->quant_cof_buffer = av_malloc(sizeof(*ctx->quant_cof_buffer) *

  1640.                                       num_buffers * sconf->max_order);

  1641.     ctx->lpc_cof_buffer   = av_malloc(sizeof(*ctx->lpc_cof_buffer) *

  1642.                                       num_buffers * sconf->max_order);

  1643.     ctx->lpc_cof_reversed_buffer = av_malloc(sizeof(*ctx->lpc_cof_buffer) *

  1644.                                              sconf->max_order);

  1645. 

  1646.     if (!ctx->quant_cof              || !ctx->lpc_cof        ||

  1647.         !ctx->quant_cof_buffer       || !ctx->lpc_cof_buffer ||

  1648.         !ctx->lpc_cof_reversed_buffer) {

  1649.         av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1650.         return AVERROR(ENOMEM);

  1651.     }

  1652. 

  1653.     // assign quantized parcor coefficient buffers

  1654.     for (c = 0; c < num_buffers; c++) {

  1655.         ctx->quant_cof[c] = ctx->quant_cof_buffer + c * sconf->max_order;

  1656.         ctx->lpc_cof[c]   = ctx->lpc_cof_buffer   + c * sconf->max_order;

  1657.     }

  1658. 

  1659.     // allocate and assign lag and gain data buffer for ltp mode

  1660.     ctx->const_block     = av_malloc (sizeof(*ctx->const_block) * num_buffers);

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

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

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

  1664.     ctx->use_ltp         = av_mallocz(sizeof(*ctx->use_ltp)  * num_buffers);

  1665.     ctx->ltp_lag         = av_malloc (sizeof(*ctx->ltp_lag)  * num_buffers);

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

  1667.     ctx->ltp_gain_buffer = av_malloc (sizeof(*ctx->ltp_gain_buffer) *

  1668.                                       num_buffers * 5);

  1669. 

  1670.     if (!ctx->const_block || !ctx->shift_lsbs ||

  1671.         !ctx->opt_order || !ctx->store_prev_samples ||

  1672.         !ctx->use_ltp  || !ctx->ltp_lag ||

  1673.         !ctx->ltp_gain || !ctx->ltp_gain_buffer) {

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

  1675.         decode_end(avctx);

  1676.         return AVERROR(ENOMEM);

  1677.     }

  1678. 

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

  1680.         ctx->ltp_gain[c] = ctx->ltp_gain_buffer + c * 5;

  1681. 

  1682.     // allocate and assign channel data buffer for mcc mode

  1683.     if (sconf->mc_coding) {

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

  1685.                                            num_buffers * num_buffers);

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

  1687.                                            num_buffers);

  1688.         ctx->reverted_channels = av_malloc(sizeof(*ctx->reverted_channels) *

  1689.                                            num_buffers);

  1690. 

  1691.         if (!ctx->chan_data_buffer || !ctx->chan_data || !ctx->reverted_channels) {

  1692.             av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1693.             decode_end(avctx);

  1694.             return AVERROR(ENOMEM);

  1695.         }

  1696. 

  1697.         for (c = 0; c < num_buffers; c++)

  1698.             ctx->chan_data[c] = ctx->chan_data_buffer + c * num_buffers;

  1699.     } else {

  1700.         ctx->chan_data         = NULL;

  1701.         ctx->chan_data_buffer  = NULL;

  1702.         ctx->reverted_channels = NULL;

  1703.     }

  1704. 

  1705.     channel_size      = sconf->frame_length + sconf->max_order;

  1706. 

  1707.     ctx->prev_raw_samples = av_malloc (sizeof(*ctx->prev_raw_samples) * sconf->max_order);

  1708.     ctx->raw_buffer       = av_mallocz(sizeof(*ctx->     raw_buffer)  * avctx->channels * channel_size);

  1709.     ctx->raw_samples      = av_malloc (sizeof(*ctx->     raw_samples) * avctx->channels);

  1710. 

  1711.     // allocate previous raw sample buffer

  1712.     if (!ctx->prev_raw_samples || !ctx->raw_buffer|| !ctx->raw_samples) {

  1713.         av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1714.         decode_end(avctx);

  1715.         return AVERROR(ENOMEM);

  1716.     }

  1717. 

  1718.     // assign raw samples buffers

  1719.     ctx->raw_samples[0] = ctx->raw_buffer + sconf->max_order;

  1720.     for (c = 1; c < avctx->channels; c++)

  1721.         ctx->raw_samples[c] = ctx->raw_samples[c - 1] + channel_size;

  1722. 

  1723.     // allocate crc buffer

  1724.     if (HAVE_BIGENDIAN != sconf->msb_first && sconf->crc_enabled &&

  1725.         (avctx->err_recognition & AV_EF_CRCCHECK)) {

  1726.         ctx->crc_buffer = av_malloc(sizeof(*ctx->crc_buffer) *

  1727.                                     ctx->cur_frame_length *

  1728.                                     avctx->channels *

  1729.                                     av_get_bytes_per_sample(avctx->sample_fmt));

  1730.         if (!ctx->crc_buffer) {

  1731.             av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1732.             decode_end(avctx);

  1733.             return AVERROR(ENOMEM);

  1734.         }

  1735.     }

  1736. 

  1737.     ff_dsputil_init(&ctx->dsp, avctx);

  1738. 

  1739.     avcodec_get_frame_defaults(&ctx->frame);

  1740.     avctx->coded_frame = &ctx->frame;

  1741. 

  1742.     return 0;

  1743. }

  1744. 

  1745. 

  1746. /** Flush (reset) the frame ID after seeking.

  1747.  */

  1748. static av_cold void flush(AVCodecContext *avctx)

  1749. {

  1750.     ALSDecContext *ctx = avctx->priv_data;

  1751. 

  1752.     ctx->frame_id = 0;

  1753. }

  1754. 

  1755. 

  1756. AVCodec ff_als_decoder = {

  1757.     .name           = "als",

  1758.     .type           = AVMEDIA_TYPE_AUDIO,

  1759.     .id             = AV_CODEC_ID_MP4ALS,

  1760.     .priv_data_size = sizeof(ALSDecContext),

  1761.     .init           = decode_init,

  1762.     .close          = decode_end,

  1763.     .decode         = decode_frame,

  1764.     .flush          = flush,

  1765.     .capabilities   = CODEC_CAP_SUBFRAMES | CODEC_CAP_DR1,

  1766.     .long_name      = NULL_IF_CONFIG_SMALL("MPEG-4 Audio Lossless Coding (ALS)"),

  1767. };