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FFmpeg/libavcodec/alsdec.c

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  1. /*

  2.  * MPEG-4 ALS decoder

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

  4.  *

  5.  * This file is part of FFmpeg.

  6.  *

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

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

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

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

  11.  *

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

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

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

  15.  * Lesser General Public License for more details.

  16.  *

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

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

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

  20.  */

  21. 

  22. /**

  23.  * @file libavcodec/alsdec.c

  24.  * MPEG-4 ALS decoder

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

  26.  */

  27. 

  28. 

  29. //#define DEBUG

  30. 

  31. 

  32. #include "avcodec.h"

  33. #include "get_bits.h"

  34. #include "unary.h"

  35. #include "mpeg4audio.h"

  36. #include "bytestream.h"

  37. 

  38. #include <stdint.h>

  39. 

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

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

  42.  *  by the encoder and stored in ALSSpecificConfig.

  43.  */

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

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

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

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

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

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

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

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

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

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

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

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

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

  57. };

  58. 

  59. 

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

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

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

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

  64.  */

  65. static const int16_t parcor_scaled_values[] = {

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  98. };

  99. 

  100. 

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

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

  103.  */

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

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

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

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

  108.     {88, 92, 96, 100}

  109. };

  110. 

  111. 

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

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

  114.  */

  115. static const int16_t mcc_weightings[] = {

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

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

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

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

  120. };

  121. 

  122. 

  123. enum RA_Flag {

  124.     RA_FLAG_NONE,

  125.     RA_FLAG_FRAMES,

  126.     RA_FLAG_HEADER

  127. };

  128. 

  129. 

  130. typedef struct {

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  153. } ALSSpecificConfig;

  154. 

  155. 

  156. typedef struct {

  157.     int stop_flag;

  158.     int master_channel;

  159.     int time_diff_flag;

  160.     int time_diff_sign;

  161.     int time_diff_index;

  162.     int weighting[6];

  163. } ALSChannelData;

  164. 

  165. 

  166. typedef struct {

  167.     AVCodecContext *avctx;

  168.     ALSSpecificConfig sconf;

  169.     GetBitContext gb;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  189. } ALSDecContext;

  190. 

  191. 

  192. typedef struct {

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  209. } ALSBlockData;

  210. 

  211. 

  212. static av_cold void dprint_specific_config(ALSDecContext *ctx)

  213. {

  214. #ifdef DEBUG

  215.     AVCodecContext *avctx    = ctx->avctx;

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

  217. 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  238. #endif

  239. }

  240. 

  241. 

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

  243.  */

  244. static av_cold int read_specific_config(ALSDecContext *ctx)

  245. {

  246.     GetBitContext gb;

  247.     uint64_t ht_size;

  248.     int i, config_offset, crc_enabled;

  249.     MPEG4AudioConfig m4ac;

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

  251.     AVCodecContext *avctx    = ctx->avctx;

  252.     uint32_t als_id;

  253. 

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

  255. 

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

  257.                                              avctx->extradata_size);

  258. 

  259.     if (config_offset < 0)

  260.         return -1;

  261. 

  262.     skip_bits_long(&gb, config_offset);

  263. 

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

  265.         return -1;

  266. 

  267.     // read the fixed items

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

  269.     avctx->sample_rate          = m4ac.sample_rate;

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

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

  272.     avctx->channels             = m4ac.channels;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  292.     crc_enabled                 = get_bits1(&gb);

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

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

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

  296. 

  297. 

  298.     // check for ALSSpecificConfig struct

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

  300.         return -1;

  301. 

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

  303. 

  304.     // read channel config

  305.     if (sconf->chan_config)

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

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

  308. 

  309. 

  310.     // read channel sorting

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

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

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

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

  315.             return -1;

  316. 

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

  318.             return AVERROR(ENOMEM);

  319. 

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

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

  322. 

  323.         align_get_bits(&gb);

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

  325.     } else {

  326.         sconf->chan_sort = 0;

  327.     }

  328. 

  329. 

  330.     // read fixed header and trailer sizes,

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

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

  333.         return -1;

  334. 

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

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

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

  338.         sconf->header_size  = 0;

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

  340.         sconf->trailer_size = 0;

  341. 

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

  343. 

  344. 

  345.     // skip the header and trailer data

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

  347.         return -1;

  348. 

  349.     if (ht_size > INT32_MAX)

  350.         return -1;

  351. 

  352.     skip_bits_long(&gb, ht_size);

  353. 

  354. 

  355.     // skip the crc data

  356.     if (crc_enabled) {

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

  358.             return -1;

  359. 

  360.         skip_bits_long(&gb, 32);

  361.     }

  362. 

  363. 

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

  365. 

  366.     dprint_specific_config(ctx);

  367. 

  368.     return 0;

  369. }

  370. 

  371. 

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

  373.  */

  374. static int check_specific_config(ALSDecContext *ctx)

  375. {

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

  377.     int error = 0;

  378. 

  379.     // report unsupported feature and set error value

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

  381.     {                                                   \

  382.         if (cond) {                                     \

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

  384.             error = errval;                             \

  385.         }                                               \

  386.     }

  387. 

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

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

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

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

  392. 

  393.     return error;

  394. }

  395. 

  396. 

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

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

  399.  */

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

  401.                           unsigned int div, unsigned int **div_blocks,

  402.                           unsigned int *num_blocks)

  403. {

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

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

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

  407.         n   *= 2;

  408.         div += 1;

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

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

  411.     } else {

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

  413.         // (bit implicitly not set)

  414.         **div_blocks = div;

  415.         (*div_blocks)++;

  416.         (*num_blocks)++;

  417.     }

  418. }

  419. 

  420. 

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

  422.  */

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

  424. {

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

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

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

  428. 

  429.     if (k > 1) {

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

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

  432.     } else if (!k) {

  433.         q >>= 1;

  434.     }

  435.     return r ? q : ~q;

  436. }

  437. 

  438. 

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

  440.  */

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

  442. {

  443.     int i, j;

  444. 

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

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

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

  448.         cof[i]  += tmp1;

  449.     }

  450.     if (i == j)

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

  452. 

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

  454. }

  455. 

  456. 

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

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

  459.  *  actual number of samples.

  460.  */

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

  462.                             uint32_t *bs_info)

  463. {

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

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

  466.     unsigned int *ptr_div_blocks = div_blocks;

  467.     unsigned int b;

  468. 

  469.     if (sconf->block_switching) {

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

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

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

  473.     }

  474. 

  475.     ctx->num_blocks = 0;

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

  477. 

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

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

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

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

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

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

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

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

  486.     // codec RM22 revision 2.

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

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

  489.     // of 14496-3.

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

  491.     // frame.

  492. 

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

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

  495. 

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

  497.         unsigned int remaining = ctx->cur_frame_length;

  498. 

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

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

  501.                 div_blocks[b] = remaining;

  502.                 ctx->num_blocks = b + 1;

  503.                 break;

  504.             }

  505. 

  506.             remaining -= div_blocks[b];

  507.         }

  508.     }

  509. }

  510. 

  511. 

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

  513.  */

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

  515. {

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

  517.     AVCodecContext *avctx    = ctx->avctx;

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

  519. 

  520.     bd->const_val    = 0;

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

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

  523. 

  524.     // skip 5 reserved bits

  525.     skip_bits(gb, 5);

  526. 

  527.     if (bd->const_block) {

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

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

  530.     }

  531. 

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

  533.     bd->const_block = 1;

  534. }

  535. 

  536. 

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

  538.  */

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

  540. {

  541.     int      smp = bd->block_length;

  542.     int32_t  val = bd->const_val;

  543.     int32_t *dst = bd->raw_samples;

  544. 

  545.     // write raw samples into buffer

  546.     for (; smp; smp--)

  547.         *dst++ = val;

  548. }

  549. 

  550. 

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

  552.  */

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

  554. {

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

  556.     AVCodecContext *avctx    = ctx->avctx;

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

  558.     unsigned int k;

  559.     unsigned int s[8];

  560.     unsigned int sub_blocks, log2_sub_blocks, sb_length;

  561.     unsigned int start      = 0;

  562.     unsigned int opt_order;

  563.     int          sb;

  564.     int32_t      *quant_cof = bd->quant_cof;

  565. 

  566. 

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

  568.     bd->const_block = 0;

  569. 

  570.     bd->opt_order   = 1;

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

  572. 

  573.     opt_order       = bd->opt_order;

  574. 

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

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

  577.         log2_sub_blocks = 0;

  578.     } else {

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

  580.             log2_sub_blocks = get_bits(gb, 2);

  581.         else

  582.             log2_sub_blocks = 2 * get_bits1(gb);

  583.     }

  584. 

  585.     sub_blocks = 1 << log2_sub_blocks;

  586. 

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

  588.     // block_length must be evenly divisible by sub_blocks

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

  590.         av_log(avctx, AV_LOG_WARNING,

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

  592.         return -1;

  593.     }

  594. 

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

  596. 

  597. 

  598.     if (sconf->bgmc) {

  599.         // TODO: BGMC mode

  600.     } else {

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

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

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

  604.     }

  605. 

  606.     if (get_bits1(gb))

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

  608. 

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

  610. 

  611. 

  612.     if (!sconf->rlslms) {

  613.         if (sconf->adapt_order) {

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

  615.                                                 2, sconf->max_order + 1));

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

  617.         } else {

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

  619.         }

  620. 

  621.         opt_order = bd->opt_order;

  622. 

  623.         if (opt_order) {

  624.             int add_base;

  625. 

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

  627.                 add_base = 0x7F;

  628. 

  629.                 // read coefficient 0

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

  631. 

  632.                 // read coefficient 1

  633.                 if (opt_order > 1)

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

  635. 

  636.                 // read coefficients 2 to opt_order

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

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

  639.             } else {

  640.                 int k_max;

  641.                 add_base = 1;

  642. 

  643.                 // read coefficient 0 to 19

  644.                 k_max = FFMIN(opt_order, 20);

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

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

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

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

  649.                 }

  650. 

  651.                 // read coefficients 20 to 126

  652.                 k_max = FFMIN(opt_order, 127);

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

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

  655. 

  656.                 // read coefficients 127 to opt_order

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

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

  659. 

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

  661. 

  662.                 if (opt_order > 1)

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

  664.             }

  665. 

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

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

  668.         }

  669.     }

  670. 

  671.     // read LTP gain and lag values

  672.     if (sconf->long_term_prediction) {

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

  674. 

  675.         if (*bd->use_ltp) {

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

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

  678. 

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

  680. 

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

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

  683. 

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

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

  686.         }

  687.     }

  688. 

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

  690.     if (bd->ra_block) {

  691.         if (opt_order)

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

  693.         if (opt_order > 1)

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

  695.         if (opt_order > 2)

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

  697. 

  698.         start = FFMIN(opt_order, 3);

  699.     }

  700. 

  701.     // read all residuals

  702.     if (sconf->bgmc) {

  703.         // TODO: BGMC mode

  704.     } else {

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

  706. 

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

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

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

  710.      }

  711. 

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

  713.         align_get_bits(gb);

  714. 

  715.     return 0;

  716. }

  717. 

  718. 

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

  720.  */

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

  722. {

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

  724.     unsigned int block_length = bd->block_length;

  725.     unsigned int smp = 0;

  726.     unsigned int k;

  727.     int opt_order             = bd->opt_order;

  728.     int sb;

  729.     int64_t y;

  730.     int32_t *quant_cof        = bd->quant_cof;

  731.     int32_t *lpc_cof          = bd->lpc_cof;

  732.     int32_t *raw_samples      = bd->raw_samples;

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

  734.     int32_t lpc_cof_reversed[opt_order];

  735. 

  736.     // reverse long-term prediction

  737.     if (*bd->use_ltp) {

  738.         int ltp_smp;

  739. 

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

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

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

  743.             int end    = center + 3;

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

  745.             int base;

  746. 

  747.             y = 1 << 6;

  748. 

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

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

  751. 

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

  753.         }

  754.     }

  755. 

  756.     // reconstruct all samples from residuals

  757.     if (bd->ra_block) {

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

  759.             y = 1 << 19;

  760. 

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

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

  763. 

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

  765.             parcor_to_lpc(smp, quant_cof, lpc_cof);

  766.         }

  767.     } else {

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

  769.             parcor_to_lpc(k, quant_cof, lpc_cof);

  770. 

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

  772.         if (bd->store_prev_samples)

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

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

  775. 

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

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

  778.             int32_t *left, *right;

  779. 

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

  781.                 left  = raw_samples;

  782.                 right = bd->raw_other;

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

  784.                 left  = bd->raw_other;

  785.                 right = raw_samples;

  786.             }

  787. 

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

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

  790.         }

  791. 

  792.         // reconstruct shifted signal

  793.         if (bd->shift_lsbs)

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

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

  796.     }

  797. 

  798.     // reverse linear prediction coefficients for efficiency

  799.     lpc_cof = lpc_cof + opt_order;

  800. 

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

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

  803. 

  804.     // reconstruct raw samples

  805.     raw_samples = bd->raw_samples + smp;

  806.     lpc_cof     = lpc_cof_reversed + opt_order;

  807. 

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

  809.         y = 1 << 19;

  810. 

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

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

  813. 

  814.         *raw_samples -= y >> 20;

  815.     }

  816. 

  817.     raw_samples = bd->raw_samples;

  818. 

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

  820.     if (bd->store_prev_samples)

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

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

  823. 

  824.     return 0;

  825. }

  826. 

  827. 

  828. /** Reads the block data.

  829.  */

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

  831. {

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

  833. 

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

  835.     if (get_bits1(gb)) {

  836.         if (read_var_block_data(ctx, bd))

  837.             return -1;

  838.     } else {

  839.         read_const_block_data(ctx, bd);

  840.     }

  841. 

  842.     return 0;

  843. }

  844. 

  845. 

  846. /** Decodes the block data.

  847.  */

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

  849. {

  850.     unsigned int smp;

  851. 

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

  853.     if (bd->const_block)

  854.         decode_const_block_data(ctx, bd);

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

  856.         return -1;

  857. 

  858.     // TODO: read RLSLMS extension data

  859. 

  860.     if (bd->shift_lsbs)

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

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

  863. 

  864.     return 0;

  865. }

  866. 

  867. 

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

  869.  */

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

  871. {

  872.     int ret;

  873. 

  874.     ret = read_block(ctx, bd);

  875. 

  876.     if (ret)

  877.         return ret;

  878. 

  879.     ret = decode_block(ctx, bd);

  880. 

  881.     return ret;

  882. }

  883. 

  884. 

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

  886.  *  sets these samples to zero.

  887.  */

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

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

  890. {

  891.     unsigned int count = 0;

  892. 

  893.     while (b < b_max)

  894.         count += div_blocks[b];

  895. 

  896.     if (count)

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

  898. }

  899. 

  900. 

  901. /** Decodes blocks independently.

  902.  */

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

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

  905.                              unsigned int *js_blocks)

  906. {

  907.     unsigned int b;

  908.     ALSBlockData bd;

  909. 

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

  911. 

  912.     bd.ra_block         = ra_frame;

  913.     bd.use_ltp          = ctx->use_ltp;

  914.     bd.ltp_lag          = ctx->ltp_lag;

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

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

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

  918.     bd.prev_raw_samples = ctx->prev_raw_samples;

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

  920. 

  921. 

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

  923.         bd.shift_lsbs       = 0;

  924.         bd.block_length     = div_blocks[b];

  925. 

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

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

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

  929.             return -1;

  930.         }

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

  932.         bd.ra_block     = 0;

  933.     }

  934. 

  935.     return 0;

  936. }

  937. 

  938. 

  939. /** Decodes blocks dependently.

  940.  */

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

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

  943.                          unsigned int *js_blocks)

  944. {

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

  946.     unsigned int offset = 0;

  947.     unsigned int b;

  948.     ALSBlockData bd[2];

  949. 

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

  951. 

  952.     bd[0].ra_block         = ra_frame;

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

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

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

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

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

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

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

  960. 

  961.     bd[1].ra_block         = ra_frame;

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

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

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

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

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

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

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

  969. 

  970.     // decode all blocks

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

  972.         unsigned int s;

  973. 

  974.         bd[0].shift_lsbs   = 0;

  975.         bd[1].shift_lsbs   = 0;

  976. 

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

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

  979. 

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

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

  982. 

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

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

  985. 

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

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

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

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

  990.             return -1;

  991.         }

  992. 

  993.         // reconstruct joint-stereo blocks

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

  995.             if (bd[1].js_blocks)

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

  997. 

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

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

  1000.         } else if (bd[1].js_blocks) {

  1001.             for (s = 0; s < div_blocks[b]; s++)

  1002.                 bd[1].raw_samples[s] = bd[1].raw_samples[s] + bd[0].raw_samples[s];

  1003.         }

  1004. 

  1005.         offset  += div_blocks[b];

  1006.         bd[0].ra_block = 0;

  1007.         bd[1].ra_block = 0;

  1008.     }

  1009. 

  1010.     // store carryover raw samples,

  1011.     // the others channel raw samples are stored by the calling function.

  1012.     memmove(ctx->raw_samples[c] - sconf->max_order,

  1013.             ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1014.             sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1015. 

  1016.     return 0;

  1017. }

  1018. 

  1019. 

  1020. /** Reads the channel data.

  1021.   */

  1022. static int read_channel_data(ALSDecContext *ctx, ALSChannelData *cd, int c)

  1023. {

  1024.     GetBitContext *gb       = &ctx->gb;

  1025.     ALSChannelData *current = cd;

  1026.     unsigned int channels   = ctx->avctx->channels;

  1027.     int entries             = 0;

  1028. 

  1029.     while (entries < channels && !(current->stop_flag = get_bits1(gb))) {

  1030.         current->master_channel = get_bits_long(gb, av_ceil_log2(channels));

  1031. 

  1032.         if (current->master_channel >= channels) {

  1033.             av_log(ctx->avctx, AV_LOG_ERROR, "Invalid master channel!\n");

  1034.             return -1;

  1035.         }

  1036. 

  1037.         if (current->master_channel != c) {

  1038.             current->time_diff_flag = get_bits1(gb);

  1039.             current->weighting[0]   = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 32)];

  1040.             current->weighting[1]   = mcc_weightings[av_clip(decode_rice(gb, 2) + 14, 0, 32)];

  1041.             current->weighting[2]   = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 32)];

  1042. 

  1043.             if (current->time_diff_flag) {

  1044.                 current->weighting[3] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 32)];

  1045.                 current->weighting[4] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 32)];

  1046.                 current->weighting[5] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 32)];

  1047. 

  1048.                 current->time_diff_sign  = get_bits1(gb);

  1049.                 current->time_diff_index = get_bits(gb, ctx->ltp_lag_length - 3) + 3;

  1050.             }

  1051.         }

  1052. 

  1053.         current++;

  1054.         entries++;

  1055.     }

  1056. 

  1057.     if (entries == channels) {

  1058.         av_log(ctx->avctx, AV_LOG_ERROR, "Damaged channel data!\n");

  1059.         return -1;

  1060.     }

  1061. 

  1062.     align_get_bits(gb);

  1063.     return 0;

  1064. }

  1065. 

  1066. 

  1067. /** Recursively reverts the inter-channel correlation for a block.

  1068.  */

  1069. static int revert_channel_correlation(ALSDecContext *ctx, ALSBlockData *bd,

  1070.                                        ALSChannelData **cd, int *reverted,

  1071.                                        unsigned int offset, int c)

  1072. {

  1073.     ALSChannelData *ch = cd[c];

  1074.     unsigned int   dep = 0;

  1075.     unsigned int channels = ctx->avctx->channels;

  1076. 

  1077.     if (reverted[c])

  1078.         return 0;

  1079. 

  1080.     reverted[c] = 1;

  1081. 

  1082.     while (dep < channels && !ch[dep].stop_flag) {

  1083.         revert_channel_correlation(ctx, bd, cd, reverted, offset,

  1084.                                    ch[dep].master_channel);

  1085. 

  1086.         dep++;

  1087.     }

  1088. 

  1089.     if (dep == channels) {

  1090.         av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel correlation!\n");

  1091.         return -1;

  1092.     }

  1093. 

  1094.     bd->use_ltp     = ctx->use_ltp + c;

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

  1096.     bd->ltp_gain    = ctx->ltp_gain[c];

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

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

  1099.     bd->raw_samples = ctx->raw_samples[c] + offset;

  1100. 

  1101.     dep = 0;

  1102.     while (!ch[dep].stop_flag) {

  1103.         unsigned int smp;

  1104.         unsigned int begin = 1;

  1105.         unsigned int end   = bd->block_length - 1;

  1106.         int64_t y;

  1107.         int32_t *master = ctx->raw_samples[ch[dep].master_channel] + offset;

  1108. 

  1109.         if (ch[dep].time_diff_flag) {

  1110.             int t = ch[dep].time_diff_index;

  1111. 

  1112.             if (ch[dep].time_diff_sign) {

  1113.                 t      = -t;

  1114.                 begin -= t;

  1115.             } else {

  1116.                 end   -= t;

  1117.             }

  1118. 

  1119.             for (smp = begin; smp < end; smp++) {

  1120.                 y  = (1 << 6) +

  1121.                      MUL64(ch[dep].weighting[0], master[smp - 1    ]) +

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

  1123.                      MUL64(ch[dep].weighting[2], master[smp + 1    ]) +

  1124.                      MUL64(ch[dep].weighting[3], master[smp - 1 + t]) +

  1125.                      MUL64(ch[dep].weighting[4], master[smp     + t]) +

  1126.                      MUL64(ch[dep].weighting[5], master[smp + 1 + t]);

  1127. 

  1128.                 bd->raw_samples[smp] += y >> 7;

  1129.             }

  1130.         } else {

  1131.             for (smp = begin; smp < end; smp++) {

  1132.                 y  = (1 << 6) +

  1133.                      MUL64(ch[dep].weighting[0], master[smp - 1]) +

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

  1135.                      MUL64(ch[dep].weighting[2], master[smp + 1]);

  1136. 

  1137.                 bd->raw_samples[smp] += y >> 7;

  1138.             }

  1139.         }

  1140. 

  1141.         dep++;

  1142.     }

  1143. 

  1144.     return 0;

  1145. }

  1146. 

  1147. 

  1148. /** Reads the frame data.

  1149.  */

  1150. static int read_frame_data(ALSDecContext *ctx, unsigned int ra_frame)

  1151. {

  1152.     ALSSpecificConfig *sconf = &ctx->sconf;

  1153.     AVCodecContext *avctx    = ctx->avctx;

  1154.     GetBitContext *gb = &ctx->gb;

  1155.     unsigned int div_blocks[32];                ///< block sizes.

  1156.     unsigned int c;

  1157.     unsigned int js_blocks[2];

  1158. 

  1159.     uint32_t bs_info = 0;

  1160. 

  1161.     // skip the size of the ra unit if present in the frame

  1162.     if (sconf->ra_flag == RA_FLAG_FRAMES && ra_frame)

  1163.         skip_bits_long(gb, 32);

  1164. 

  1165.     if (sconf->mc_coding && sconf->joint_stereo) {

  1166.         ctx->js_switch = get_bits1(gb);

  1167.         align_get_bits(gb);

  1168.     }

  1169. 

  1170.     if (!sconf->mc_coding || ctx->js_switch) {

  1171.         int independent_bs = !sconf->joint_stereo;

  1172. 

  1173.         for (c = 0; c < avctx->channels; c++) {

  1174.             js_blocks[0] = 0;

  1175.             js_blocks[1] = 0;

  1176. 

  1177.             get_block_sizes(ctx, div_blocks, &bs_info);

  1178. 

  1179.             // if joint_stereo and block_switching is set, independent decoding

  1180.             // is signaled via the first bit of bs_info

  1181.             if (sconf->joint_stereo && sconf->block_switching)

  1182.                 if (bs_info >> 31)

  1183.                     independent_bs = 2;

  1184. 

  1185.             // if this is the last channel, it has to be decoded independently

  1186.             if (c == avctx->channels - 1)

  1187.                 independent_bs = 1;

  1188. 

  1189.             if (independent_bs) {

  1190.                 if (decode_blocks_ind(ctx, ra_frame, c, div_blocks, js_blocks))

  1191.                     return -1;

  1192. 

  1193.                 independent_bs--;

  1194.             } else {

  1195.                 if (decode_blocks(ctx, ra_frame, c, div_blocks, js_blocks))

  1196.                     return -1;

  1197. 

  1198.                 c++;

  1199.             }

  1200. 

  1201.             // store carryover raw samples

  1202.             memmove(ctx->raw_samples[c] - sconf->max_order,

  1203.                     ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1204.                     sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1205.         }

  1206.     } else { // multi-channel coding

  1207.         ALSBlockData   bd;

  1208.         int            b;

  1209.         int            *reverted_channels = ctx->reverted_channels;

  1210.         unsigned int   offset             = 0;

  1211. 

  1212.         for (c = 0; c < avctx->channels; c++)

  1213.             if (ctx->chan_data[c] < ctx->chan_data_buffer) {

  1214.                 av_log(ctx->avctx, AV_LOG_ERROR, "Invalid channel data!\n");

  1215.                 return -1;

  1216.             }

  1217. 

  1218.         memset(&bd,               0, sizeof(ALSBlockData));

  1219.         memset(reverted_channels, 0, sizeof(*reverted_channels) * avctx->channels);

  1220. 

  1221.         bd.ra_block         = ra_frame;

  1222.         bd.prev_raw_samples = ctx->prev_raw_samples;

  1223. 

  1224.         get_block_sizes(ctx, div_blocks, &bs_info);

  1225. 

  1226.         for (b = 0; b < ctx->num_blocks; b++) {

  1227.             bd.shift_lsbs   = 0;

  1228.             bd.block_length = div_blocks[b];

  1229. 

  1230.             for (c = 0; c < avctx->channels; c++) {

  1231.                 bd.use_ltp     = ctx->use_ltp + c;

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

  1233.                 bd.ltp_gain    = ctx->ltp_gain[c];

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

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

  1236.                 bd.raw_samples = ctx->raw_samples[c] + offset;

  1237.                 bd.raw_other   = NULL;

  1238. 

  1239.                 read_block(ctx, &bd);

  1240.                 if (read_channel_data(ctx, ctx->chan_data[c], c))

  1241.                     return -1;

  1242.             }

  1243. 

  1244.             for (c = 0; c < avctx->channels; c++)

  1245.                 if (revert_channel_correlation(ctx, &bd, ctx->chan_data,

  1246.                                                reverted_channels, offset, c))

  1247.                     return -1;

  1248. 

  1249.             for (c = 0; c < avctx->channels; c++) {

  1250.                 bd.use_ltp     = ctx->use_ltp + c;

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

  1252.                 bd.ltp_gain    = ctx->ltp_gain[c];

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

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

  1255.                 bd.raw_samples = ctx->raw_samples[c] + offset;

  1256.                 decode_block(ctx, &bd);

  1257.             }

  1258. 

  1259.             memset(reverted_channels, 0, avctx->channels * sizeof(*reverted_channels));

  1260.             offset      += div_blocks[b];

  1261.             bd.ra_block  = 0;

  1262.         }

  1263. 

  1264.         // store carryover raw samples

  1265.         for (c = 0; c < avctx->channels; c++)

  1266.             memmove(ctx->raw_samples[c] - sconf->max_order,

  1267.                     ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1268.                     sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1269.     }

  1270. 

  1271.     // TODO: read_diff_float_data

  1272. 

  1273.     return 0;

  1274. }

  1275. 

  1276. 

  1277. /** Decodes an ALS frame.

  1278.  */

  1279. static int decode_frame(AVCodecContext *avctx,

  1280.                         void *data, int *data_size,

  1281.                         AVPacket *avpkt)

  1282. {

  1283.     ALSDecContext *ctx       = avctx->priv_data;

  1284.     ALSSpecificConfig *sconf = &ctx->sconf;

  1285.     const uint8_t *buffer    = avpkt->data;

  1286.     int buffer_size          = avpkt->size;

  1287.     int invalid_frame, size;

  1288.     unsigned int c, sample, ra_frame, bytes_read, shift;

  1289. 

  1290.     init_get_bits(&ctx->gb, buffer, buffer_size * 8);

  1291. 

  1292.     // In the case that the distance between random access frames is set to zero

  1293.     // (sconf->ra_distance == 0) no frame is treated as a random access frame.

  1294.     // For the first frame, if prediction is used, all samples used from the

  1295.     // previous frame are assumed to be zero.

  1296.     ra_frame = sconf->ra_distance && !(ctx->frame_id % sconf->ra_distance);

  1297. 

  1298.     // the last frame to decode might have a different length

  1299.     if (sconf->samples != 0xFFFFFFFF)

  1300.         ctx->cur_frame_length = FFMIN(sconf->samples - ctx->frame_id * (uint64_t) sconf->frame_length,

  1301.                                       sconf->frame_length);

  1302.     else

  1303.         ctx->cur_frame_length = sconf->frame_length;

  1304. 

  1305.     // decode the frame data

  1306.     if ((invalid_frame = read_frame_data(ctx, ra_frame) < 0))

  1307.         av_log(ctx->avctx, AV_LOG_WARNING,

  1308.                "Reading frame data failed. Skipping RA unit.\n");

  1309. 

  1310.     ctx->frame_id++;

  1311. 

  1312.     // check for size of decoded data

  1313.     size = ctx->cur_frame_length * avctx->channels *

  1314.            (av_get_bits_per_sample_format(avctx->sample_fmt) >> 3);

  1315. 

  1316.     if (size > *data_size) {

  1317.         av_log(avctx, AV_LOG_ERROR, "Decoded data exceeds buffer size.\n");

  1318.         return -1;

  1319.     }

  1320. 

  1321.     *data_size = size;

  1322. 

  1323.     // transform decoded frame into output format

  1324.     #define INTERLEAVE_OUTPUT(bps)                                 \

  1325.     {                                                              \

  1326.         int##bps##_t *dest = (int##bps##_t*) data;                 \

  1327.         shift = bps - ctx->avctx->bits_per_raw_sample;             \

  1328.         for (sample = 0; sample < ctx->cur_frame_length; sample++) \

  1329.             for (c = 0; c < avctx->channels; c++)                  \

  1330.                 *dest++ = ctx->raw_samples[c][sample] << shift;    \

  1331.     }

  1332. 

  1333.     if (ctx->avctx->bits_per_raw_sample <= 16) {

  1334.         INTERLEAVE_OUTPUT(16)

  1335.     } else {

  1336.         INTERLEAVE_OUTPUT(32)

  1337.     }

  1338. 

  1339.     bytes_read = invalid_frame ? buffer_size :

  1340.                                  (get_bits_count(&ctx->gb) + 7) >> 3;

  1341. 

  1342.     return bytes_read;

  1343. }

  1344. 

  1345. 

  1346. /** Uninitializes the ALS decoder.

  1347.  */

  1348. static av_cold int decode_end(AVCodecContext *avctx)

  1349. {

  1350.     ALSDecContext *ctx = avctx->priv_data;

  1351. 

  1352.     av_freep(&ctx->sconf.chan_pos);

  1353. 

  1354.     av_freep(&ctx->use_ltp);

  1355.     av_freep(&ctx->ltp_lag);

  1356.     av_freep(&ctx->ltp_gain);

  1357.     av_freep(&ctx->ltp_gain_buffer);

  1358.     av_freep(&ctx->quant_cof);

  1359.     av_freep(&ctx->lpc_cof);

  1360.     av_freep(&ctx->quant_cof_buffer);

  1361.     av_freep(&ctx->lpc_cof_buffer);

  1362.     av_freep(&ctx->prev_raw_samples);

  1363.     av_freep(&ctx->raw_samples);

  1364.     av_freep(&ctx->raw_buffer);

  1365.     av_freep(&ctx->chan_data);

  1366.     av_freep(&ctx->chan_data_buffer);

  1367.     av_freep(&ctx->reverted_channels);

  1368. 

  1369.     return 0;

  1370. }

  1371. 

  1372. 

  1373. /** Initializes the ALS decoder.

  1374.  */

  1375. static av_cold int decode_init(AVCodecContext *avctx)

  1376. {

  1377.     unsigned int c;

  1378.     unsigned int channel_size;

  1379.     int num_buffers;

  1380.     ALSDecContext *ctx = avctx->priv_data;

  1381.     ALSSpecificConfig *sconf = &ctx->sconf;

  1382.     ctx->avctx = avctx;

  1383. 

  1384.     if (!avctx->extradata) {

  1385.         av_log(avctx, AV_LOG_ERROR, "Missing required ALS extradata.\n");

  1386.         return -1;

  1387.     }

  1388. 

  1389.     if (read_specific_config(ctx)) {

  1390.         av_log(avctx, AV_LOG_ERROR, "Reading ALSSpecificConfig failed.\n");

  1391.         decode_end(avctx);

  1392.         return -1;

  1393.     }

  1394. 

  1395.     if (check_specific_config(ctx)) {

  1396.         decode_end(avctx);

  1397.         return -1;

  1398.     }

  1399. 

  1400.     if (sconf->floating) {

  1401.         avctx->sample_fmt          = SAMPLE_FMT_FLT;

  1402.         avctx->bits_per_raw_sample = 32;

  1403.     } else {

  1404.         avctx->sample_fmt          = sconf->resolution > 1

  1405.                                      ? SAMPLE_FMT_S32 : SAMPLE_FMT_S16;

  1406.         avctx->bits_per_raw_sample = (sconf->resolution + 1) * 8;

  1407.     }

  1408. 

  1409.     // set lag value for long-term prediction

  1410.     ctx->ltp_lag_length = 8 + (avctx->sample_rate >=  96000) +

  1411.                               (avctx->sample_rate >= 192000);

  1412. 

  1413.     // allocate quantized parcor coefficient buffer

  1414.     num_buffers = sconf->mc_coding ? avctx->channels : 1;

  1415. 

  1416.     ctx->quant_cof        = av_malloc(sizeof(*ctx->quant_cof) * num_buffers);

  1417.     ctx->lpc_cof          = av_malloc(sizeof(*ctx->lpc_cof)   * num_buffers);

  1418.     ctx->quant_cof_buffer = av_malloc(sizeof(*ctx->quant_cof_buffer) *

  1419.                                       num_buffers * sconf->max_order);

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

  1421.                                       num_buffers * sconf->max_order);

  1422. 

  1423.     if (!ctx->quant_cof        || !ctx->lpc_cof       ||

  1424.         !ctx->quant_cof_buffer || !ctx->lpc_cof_buffer) {

  1425.         av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1426.         return AVERROR(ENOMEM);

  1427.     }

  1428. 

  1429.     // assign quantized parcor coefficient buffers

  1430.     for (c = 0; c < num_buffers; c++) {

  1431.         ctx->quant_cof[c] = ctx->quant_cof_buffer + c * sconf->max_order;

  1432.         ctx->lpc_cof[c]   = ctx->lpc_cof_buffer   + c * sconf->max_order;

  1433.     }

  1434. 

  1435.     // allocate and assign lag and gain data buffer for ltp mode

  1436.     ctx->use_ltp         = av_mallocz(sizeof(*ctx->use_ltp)  * num_buffers);

  1437.     ctx->ltp_lag         = av_malloc (sizeof(*ctx->ltp_lag)  * num_buffers);

  1438.     ctx->ltp_gain        = av_malloc (sizeof(*ctx->ltp_gain) * num_buffers);

  1439.     ctx->ltp_gain_buffer = av_malloc (sizeof(*ctx->ltp_gain_buffer) *

  1440.                                       num_buffers * 5);

  1441. 

  1442.     if (!ctx->use_ltp  || !ctx->ltp_lag ||

  1443.         !ctx->ltp_gain || !ctx->ltp_gain_buffer) {

  1444.         av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1445.         decode_end(avctx);

  1446.         return AVERROR(ENOMEM);

  1447.     }

  1448. 

  1449.     for (c = 0; c < num_buffers; c++)

  1450.         ctx->ltp_gain[c] = ctx->ltp_gain_buffer + c * 5;

  1451. 

  1452.     // allocate and assign channel data buffer for mcc mode

  1453.     if (sconf->mc_coding) {

  1454.         ctx->chan_data_buffer  = av_malloc(sizeof(*ctx->chan_data_buffer) *

  1455.                                            num_buffers);

  1456.         ctx->chan_data         = av_malloc(sizeof(ALSChannelData) *

  1457.                                            num_buffers);

  1458.         ctx->reverted_channels = av_malloc(sizeof(*ctx->reverted_channels) *

  1459.                                            num_buffers);

  1460. 

  1461.         if (!ctx->chan_data_buffer || !ctx->chan_data || !ctx->reverted_channels) {

  1462.             av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1463.             decode_end(avctx);

  1464.             return AVERROR(ENOMEM);

  1465.         }

  1466. 

  1467.         for (c = 0; c < num_buffers; c++)

  1468.             ctx->chan_data[c] = ctx->chan_data_buffer + c;

  1469.     } else {

  1470.         ctx->chan_data         = NULL;

  1471.         ctx->chan_data_buffer  = NULL;

  1472.         ctx->reverted_channels = NULL;

  1473.     }

  1474. 

  1475.     avctx->frame_size = sconf->frame_length;

  1476.     channel_size      = sconf->frame_length + sconf->max_order;

  1477. 

  1478.     ctx->prev_raw_samples = av_malloc (sizeof(*ctx->prev_raw_samples) * sconf->max_order);

  1479.     ctx->raw_buffer       = av_mallocz(sizeof(*ctx->     raw_buffer)  * avctx->channels * channel_size);

  1480.     ctx->raw_samples      = av_malloc (sizeof(*ctx->     raw_samples) * avctx->channels);

  1481. 

  1482.     // allocate previous raw sample buffer

  1483.     if (!ctx->prev_raw_samples || !ctx->raw_buffer|| !ctx->raw_samples) {

  1484.         av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1485.         decode_end(avctx);

  1486.         return AVERROR(ENOMEM);

  1487.     }

  1488. 

  1489.     // assign raw samples buffers

  1490.     ctx->raw_samples[0] = ctx->raw_buffer + sconf->max_order;

  1491.     for (c = 1; c < avctx->channels; c++)

  1492.         ctx->raw_samples[c] = ctx->raw_samples[c - 1] + channel_size;

  1493. 

  1494.     return 0;

  1495. }

  1496. 

  1497. 

  1498. /** Flushes (resets) the frame ID after seeking.

  1499.  */

  1500. static av_cold void flush(AVCodecContext *avctx)

  1501. {

  1502.     ALSDecContext *ctx = avctx->priv_data;

  1503. 

  1504.     ctx->frame_id = 0;

  1505. }

  1506. 

  1507. 

  1508. AVCodec als_decoder = {

  1509.     "als",

  1510.     CODEC_TYPE_AUDIO,

  1511.     CODEC_ID_MP4ALS,

  1512.     sizeof(ALSDecContext),

  1513.     decode_init,

  1514.     NULL,

  1515.     decode_end,

  1516.     decode_frame,

  1517.     .flush = flush,

  1518.     .capabilities = CODEC_CAP_SUBFRAMES,

  1519.     .long_name = NULL_IF_CONFIG_SMALL("MPEG-4 Audio Lossless Coding (ALS)"),

  1520. };