falkTX
/
FFmpeg
mirror of https://github.com/falkTX/FFmpeg.git
1
0
Fork 0
Code Issues 0 Releases 338 Wiki Activity
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
21685 Commits
32 Branches
769MB
Tree: 1261b07f5f
Branches Tags
${ item.name }
Create branch ${ searchTerm }
from '1261b07f5f'
${ noResults }
FFmpeg/libavcodec/alsdec.c

1261 lines
43KB
Raw Blame History 

  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. enum RA_Flag {

  113.     RA_FLAG_NONE,

  114.     RA_FLAG_FRAMES,

  115.     RA_FLAG_HEADER

  116. };

  117. 

  118. 

  119. typedef struct {

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  142. } ALSSpecificConfig;

  143. 

  144. 

  145. typedef struct {

  146.     AVCodecContext *avctx;

  147.     ALSSpecificConfig sconf;

  148.     GetBitContext gb;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  163. } ALSDecContext;

  164. 

  165. 

  166. typedef struct {

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  183. } ALSBlockData;

  184. 

  185. 

  186. static av_cold void dprint_specific_config(ALSDecContext *ctx)

  187. {

  188. #ifdef DEBUG

  189.     AVCodecContext *avctx    = ctx->avctx;

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

  191. 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  212. #endif

  213. }

  214. 

  215. 

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

  217.  */

  218. static av_cold int read_specific_config(ALSDecContext *ctx)

  219. {

  220.     GetBitContext gb;

  221.     uint64_t ht_size;

  222.     int i, config_offset, crc_enabled;

  223.     MPEG4AudioConfig m4ac;

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

  225.     AVCodecContext *avctx    = ctx->avctx;

  226.     uint32_t als_id;

  227. 

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

  229. 

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

  231.                                              avctx->extradata_size);

  232. 

  233.     if (config_offset < 0)

  234.         return -1;

  235. 

  236.     skip_bits_long(&gb, config_offset);

  237. 

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

  239.         return -1;

  240. 

  241.     // read the fixed items

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

  243.     avctx->sample_rate          = m4ac.sample_rate;

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

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

  246.     avctx->channels             = m4ac.channels;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  266.     crc_enabled                 = get_bits1(&gb);

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

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

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

  270. 

  271. 

  272.     // check for ALSSpecificConfig struct

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

  274.         return -1;

  275. 

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

  277. 

  278.     // allocate quantized parcor coefficient buffer

  279.     if (!(ctx->quant_cof = av_malloc(sizeof(*ctx->quant_cof) * sconf->max_order)) ||

  280.         !(ctx->lpc_cof   = av_malloc(sizeof(*ctx->lpc_cof)   * sconf->max_order))) {

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

  282.         return AVERROR(ENOMEM);

  283.     }

  284. 

  285.     // read channel config

  286.     if (sconf->chan_config)

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

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

  289. 

  290. 

  291.     // read channel sorting

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

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

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

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

  296.             return -1;

  297. 

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

  299.             return AVERROR(ENOMEM);

  300. 

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

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

  303. 

  304.         align_get_bits(&gb);

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

  306.     } else {

  307.         sconf->chan_sort = 0;

  308.     }

  309. 

  310. 

  311.     // read fixed header and trailer sizes,

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

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

  314.         return -1;

  315. 

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

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

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

  319.         sconf->header_size  = 0;

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

  321.         sconf->trailer_size = 0;

  322. 

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

  324. 

  325. 

  326.     // skip the header and trailer data

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

  328.         return -1;

  329. 

  330.     if (ht_size > INT32_MAX)

  331.         return -1;

  332. 

  333.     skip_bits_long(&gb, ht_size);

  334. 

  335. 

  336.     // skip the crc data

  337.     if (crc_enabled) {

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

  339.             return -1;

  340. 

  341.         skip_bits_long(&gb, 32);

  342.     }

  343. 

  344. 

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

  346. 

  347.     dprint_specific_config(ctx);

  348. 

  349.     return 0;

  350. }

  351. 

  352. 

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

  354.  */

  355. static int check_specific_config(ALSDecContext *ctx)

  356. {

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

  358.     int error = 0;

  359. 

  360.     // report unsupported feature and set error value

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

  362.     {                                                   \

  363.         if (cond) {                                     \

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

  365.             error = errval;                             \

  366.         }                                               \

  367.     }

  368. 

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

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

  371.     MISSING_ERR(sconf->mc_coding,            "Multi-channel correlation",   -1);

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

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

  374. 

  375.     return error;

  376. }

  377. 

  378. 

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

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

  381.  */

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

  383.                           unsigned int div, unsigned int **div_blocks,

  384.                           unsigned int *num_blocks)

  385. {

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

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

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

  389.         n   *= 2;

  390.         div += 1;

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

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

  393.     } else {

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

  395.         // (bit implicitly not set)

  396.         **div_blocks = div;

  397.         (*div_blocks)++;

  398.         (*num_blocks)++;

  399.     }

  400. }

  401. 

  402. 

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

  404.  */

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

  406. {

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

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

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

  410. 

  411.     if (k > 1) {

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

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

  414.     } else if (!k) {

  415.         q >>= 1;

  416.     }

  417.     return r ? q : ~q;

  418. }

  419. 

  420. 

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

  422.  */

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

  424. {

  425.     int i, j;

  426. 

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

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

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

  430.         cof[i]  += tmp1;

  431.     }

  432.     if (i == j)

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

  434. 

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

  436. }

  437. 

  438. 

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

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

  441.  *  actual number of samples.

  442.  */

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

  444.                             uint32_t *bs_info)

  445. {

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

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

  448.     unsigned int *ptr_div_blocks = div_blocks;

  449.     unsigned int b;

  450. 

  451.     if (sconf->block_switching) {

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

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

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

  455.     }

  456. 

  457.     ctx->num_blocks = 0;

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

  459. 

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

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

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

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

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

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

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

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

  468.     // codec RM22 revision 2.

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

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

  471.     // of 14496-3.

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

  473.     // frame.

  474. 

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

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

  477. 

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

  479.         unsigned int remaining = ctx->cur_frame_length;

  480. 

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

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

  483.                 div_blocks[b] = remaining;

  484.                 ctx->num_blocks = b + 1;

  485.                 break;

  486.             }

  487. 

  488.             remaining -= div_blocks[b];

  489.         }

  490.     }

  491. }

  492. 

  493. 

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

  495.  */

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

  497. {

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

  499.     AVCodecContext *avctx    = ctx->avctx;

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

  501. 

  502.     bd->const_val    = 0;

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

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

  505. 

  506.     // skip 5 reserved bits

  507.     skip_bits(gb, 5);

  508. 

  509.     if (bd->const_block) {

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

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

  512.     }

  513. 

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

  515.     bd->const_block = 1;

  516. }

  517. 

  518. 

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

  520.  */

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

  522. {

  523.     int      smp = bd->block_length;

  524.     int32_t  val = bd->const_val;

  525.     int32_t *dst = bd->raw_samples;

  526. 

  527.     // write raw samples into buffer

  528.     for (; smp; smp--)

  529.         *dst++ = val;

  530. }

  531. 

  532. 

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

  534.  */

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

  536. {

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

  538.     AVCodecContext *avctx    = ctx->avctx;

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

  540.     unsigned int k;

  541.     unsigned int s[8];

  542.     unsigned int sub_blocks, log2_sub_blocks, sb_length;

  543.     unsigned int start      = 0;

  544.     unsigned int opt_order;

  545.     int          sb;

  546.     int32_t      *quant_cof = bd->quant_cof;

  547. 

  548. 

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

  550.     bd->const_block = 0;

  551. 

  552.     bd->opt_order   = 1;

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

  554. 

  555.     opt_order       = bd->opt_order;

  556. 

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

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

  559.         log2_sub_blocks = 0;

  560.     } else {

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

  562.             log2_sub_blocks = get_bits(gb, 2);

  563.         else

  564.             log2_sub_blocks = 2 * get_bits1(gb);

  565.     }

  566. 

  567.     sub_blocks = 1 << log2_sub_blocks;

  568. 

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

  570.     // block_length must be evenly divisible by sub_blocks

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

  572.         av_log(avctx, AV_LOG_WARNING,

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

  574.         return -1;

  575.     }

  576. 

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

  578. 

  579. 

  580.     if (sconf->bgmc) {

  581.         // TODO: BGMC mode

  582.     } else {

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

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

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

  586.     }

  587. 

  588.     if (get_bits1(gb))

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

  590. 

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

  592. 

  593. 

  594.     if (!sconf->rlslms) {

  595.         if (sconf->adapt_order) {

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

  597.                                                 2, sconf->max_order + 1));

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

  599.         } else {

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

  601.         }

  602. 

  603.         opt_order = bd->opt_order;

  604. 

  605.         if (opt_order) {

  606.             int add_base;

  607. 

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

  609.                 add_base = 0x7F;

  610. 

  611.                 // read coefficient 0

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

  613. 

  614.                 // read coefficient 1

  615.                 if (opt_order > 1)

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

  617. 

  618.                 // read coefficients 2 to opt_order

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

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

  621.             } else {

  622.                 int k_max;

  623.                 add_base = 1;

  624. 

  625.                 // read coefficient 0 to 19

  626.                 k_max = FFMIN(opt_order, 20);

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

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

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

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

  631.                 }

  632. 

  633.                 // read coefficients 20 to 126

  634.                 k_max = FFMIN(opt_order, 127);

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

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

  637. 

  638.                 // read coefficients 127 to opt_order

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

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

  641. 

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

  643. 

  644.                 if (opt_order > 1)

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

  646.             }

  647. 

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

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

  650.         }

  651.     }

  652. 

  653.     // read LTP gain and lag values

  654.     if (sconf->long_term_prediction) {

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

  656. 

  657.         if (*bd->use_ltp) {

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

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

  660. 

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

  662. 

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

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

  665. 

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

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

  668.         }

  669.     }

  670. 

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

  672.     if (bd->ra_block) {

  673.         if (opt_order)

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

  675.         if (opt_order > 1)

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

  677.         if (opt_order > 2)

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

  679. 

  680.         start = FFMIN(opt_order, 3);

  681.     }

  682. 

  683.     // read all residuals

  684.     if (sconf->bgmc) {

  685.         // TODO: BGMC mode

  686.     } else {

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

  688. 

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

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

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

  692.      }

  693. 

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

  695.         align_get_bits(gb);

  696. 

  697.     return 0;

  698. }

  699. 

  700. 

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

  702.  */

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

  704. {

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

  706.     unsigned int block_length = bd->block_length;

  707.     unsigned int smp = 0;

  708.     unsigned int k;

  709.     unsigned int opt_order    = bd->opt_order;

  710.     int sb;

  711.     int64_t y;

  712.     int32_t *quant_cof        = bd->quant_cof;

  713.     int32_t *lpc_cof          = bd->lpc_cof;

  714.     int32_t *raw_samples      = bd->raw_samples;

  715. 

  716.     // reverse long-term prediction

  717.     if (*bd->use_ltp) {

  718.         int ltp_smp;

  719. 

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

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

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

  723.             int end    = center + 3;

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

  725.             int base;

  726. 

  727.             y = 1 << 6;

  728. 

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

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

  731. 

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

  733.         }

  734.     }

  735. 

  736.     // reconstruct all samples from residuals

  737.     if (bd->ra_block) {

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

  739.             y = 1 << 19;

  740. 

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

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

  743. 

  744.             raw_samples[smp] -= y >> 20;

  745.             parcor_to_lpc(smp, quant_cof, lpc_cof);

  746.         }

  747.     } else {

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

  749.             parcor_to_lpc(k, quant_cof, lpc_cof);

  750. 

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

  752.         if (bd->store_prev_samples)

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

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

  755. 

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

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

  758.             int32_t *left, *right;

  759. 

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

  761.                 left  = raw_samples;

  762.                 right = bd->raw_other;

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

  764.                 left  = bd->raw_other;

  765.                 right = raw_samples;

  766.             }

  767. 

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

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

  770.         }

  771. 

  772.         // reconstruct shifted signal

  773.         if (bd->shift_lsbs)

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

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

  776.     }

  777. 

  778.     // reconstruct raw samples

  779.     for (; smp < bd->block_length; smp++) {

  780.         y = 1 << 19;

  781. 

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

  783.             y += MUL64(bd->lpc_cof[sb],raw_samples[smp - (sb + 1)]);

  784. 

  785.         raw_samples[smp] -= y >> 20;

  786.     }

  787. 

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

  789.     if (bd->store_prev_samples)

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

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

  792. 

  793.     return 0;

  794. }

  795. 

  796. 

  797. /** Reads the block data.

  798.  */

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

  800. {

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

  802. 

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

  804.     if (get_bits1(gb)) {

  805.         if (read_var_block_data(ctx, bd))

  806.             return -1;

  807.     } else {

  808.         read_const_block_data(ctx, bd);

  809.     }

  810. 

  811.     return 0;

  812. }

  813. 

  814. 

  815. /** Decodes the block data.

  816.  */

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

  818. {

  819.     unsigned int smp;

  820. 

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

  822.     if (bd->const_block)

  823.         decode_const_block_data(ctx, bd);

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

  825.         return -1;

  826. 

  827.     // TODO: read RLSLMS extension data

  828. 

  829.     if (bd->shift_lsbs)

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

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

  832. 

  833.     return 0;

  834. }

  835. 

  836. 

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

  838.  */

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

  840. {

  841.     int ret;

  842. 

  843.     ret = read_block(ctx, bd);

  844. 

  845.     if (ret)

  846.         return ret;

  847. 

  848.     ret = decode_block(ctx, bd);

  849. 

  850.     return ret;

  851. }

  852. 

  853. 

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

  855.  *  sets these samples to zero.

  856.  */

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

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

  859. {

  860.     unsigned int count = 0;

  861. 

  862.     while (b < b_max)

  863.         count += div_blocks[b];

  864. 

  865.     if (count)

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

  867. }

  868. 

  869. 

  870. /** Decodes blocks independently.

  871.  */

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

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

  874.                              unsigned int *js_blocks)

  875. {

  876.     unsigned int b;

  877.     ALSBlockData bd;

  878. 

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

  880. 

  881.     bd.ra_block         = ra_frame;

  882.     bd.use_ltp          = ctx->use_ltp;

  883.     bd.ltp_lag          = ctx->ltp_lag;

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

  885.     bd.quant_cof        = ctx->quant_cof;

  886.     bd.lpc_cof          = ctx->lpc_cof;

  887.     bd.prev_raw_samples = ctx->prev_raw_samples;

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

  889. 

  890. 

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

  892.         bd.shift_lsbs       = 0;

  893.         bd.block_length     = div_blocks[b];

  894. 

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

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

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

  898.             return -1;

  899.         }

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

  901.         bd.ra_block     = 0;

  902.     }

  903. 

  904.     return 0;

  905. }

  906. 

  907. 

  908. /** Decodes blocks dependently.

  909.  */

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

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

  912.                          unsigned int *js_blocks)

  913. {

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

  915.     unsigned int offset = 0;

  916.     unsigned int b;

  917.     ALSBlockData bd[2];

  918. 

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

  920. 

  921.     bd[0].ra_block         = ra_frame;

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

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

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

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

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

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

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

  929. 

  930.     bd[1].ra_block         = ra_frame;

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

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

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

  934.     bd[1].quant_cof        = ctx->quant_cof;

  935.     bd[1].lpc_cof          = ctx->lpc_cof;

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

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

  938. 

  939.     // decode all blocks

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

  941.         unsigned int s;

  942. 

  943.         bd[0].shift_lsbs   = 0;

  944.         bd[1].shift_lsbs   = 0;

  945. 

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

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

  948. 

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

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

  951. 

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

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

  954. 

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

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

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

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

  959.             return -1;

  960.         }

  961. 

  962.         // reconstruct joint-stereo blocks

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

  964.             if (bd[1].js_blocks)

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

  966. 

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

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

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

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

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

  972.         }

  973. 

  974.         offset  += div_blocks[b];

  975.         bd[0].ra_block = 0;

  976.         bd[1].ra_block = 0;

  977.     }

  978. 

  979.     // store carryover raw samples,

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

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

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

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

  984. 

  985.     return 0;

  986. }

  987. 

  988. 

  989. /** Reads the frame data.

  990.  */

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

  992. {

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

  994.     AVCodecContext *avctx    = ctx->avctx;

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

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

  997.     unsigned int c;

  998.     unsigned int js_blocks[2];

  999. 

  1000.     uint32_t bs_info = 0;

  1001. 

  1002.     // skip the size of the ra unit if present in the frame

  1003.     if (sconf->ra_flag == RA_FLAG_FRAMES && ra_frame)

  1004.         skip_bits_long(gb, 32);

  1005. 

  1006.     if (sconf->mc_coding && sconf->joint_stereo) {

  1007.         ctx->js_switch = get_bits1(gb);

  1008.         align_get_bits(gb);

  1009.     }

  1010. 

  1011.     if (!sconf->mc_coding || ctx->js_switch) {

  1012.         int independent_bs = !sconf->joint_stereo;

  1013. 

  1014.         for (c = 0; c < avctx->channels; c++) {

  1015.             js_blocks[0] = 0;

  1016.             js_blocks[1] = 0;

  1017. 

  1018.             get_block_sizes(ctx, div_blocks, &bs_info);

  1019. 

  1020.             // if joint_stereo and block_switching is set, independent decoding

  1021.             // is signaled via the first bit of bs_info

  1022.             if (sconf->joint_stereo && sconf->block_switching)

  1023.                 if (bs_info >> 31)

  1024.                     independent_bs = 2;

  1025. 

  1026.             // if this is the last channel, it has to be decoded independently

  1027.             if (c == avctx->channels - 1)

  1028.                 independent_bs = 1;

  1029. 

  1030.             if (independent_bs) {

  1031.                 if (decode_blocks_ind(ctx, ra_frame, c, div_blocks, js_blocks))

  1032.                     return -1;

  1033. 

  1034.                 independent_bs--;

  1035.             } else {

  1036.                 if (decode_blocks(ctx, ra_frame, c, div_blocks, js_blocks))

  1037.                     return -1;

  1038. 

  1039.                 c++;

  1040.             }

  1041. 

  1042.             // store carryover raw samples

  1043.             memmove(ctx->raw_samples[c] - sconf->max_order,

  1044.                     ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1045.                     sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1046.         }

  1047.     } else { // multi-channel coding

  1048.         get_block_sizes(ctx, div_blocks, &bs_info);

  1049. 

  1050.         // TODO: multi channel coding might use a temporary buffer instead as

  1051.         //       the actual channel is not known when read_block-data is called

  1052.         if (decode_blocks_ind(ctx, ra_frame, 0, div_blocks, js_blocks))

  1053.             return -1;

  1054.         // TODO: read_channel_data

  1055.     }

  1056. 

  1057.     // TODO: read_diff_float_data

  1058. 

  1059.     return 0;

  1060. }

  1061. 

  1062. 

  1063. /** Decodes an ALS frame.

  1064.  */

  1065. static int decode_frame(AVCodecContext *avctx,

  1066.                         void *data, int *data_size,

  1067.                         AVPacket *avpkt)

  1068. {

  1069.     ALSDecContext *ctx       = avctx->priv_data;

  1070.     ALSSpecificConfig *sconf = &ctx->sconf;

  1071.     const uint8_t *buffer    = avpkt->data;

  1072.     int buffer_size          = avpkt->size;

  1073.     int invalid_frame, size;

  1074.     unsigned int c, sample, ra_frame, bytes_read, shift;

  1075. 

  1076.     init_get_bits(&ctx->gb, buffer, buffer_size * 8);

  1077. 

  1078.     // In the case that the distance between random access frames is set to zero

  1079.     // (sconf->ra_distance == 0) no frame is treated as a random access frame.

  1080.     // For the first frame, if prediction is used, all samples used from the

  1081.     // previous frame are assumed to be zero.

  1082.     ra_frame = sconf->ra_distance && !(ctx->frame_id % sconf->ra_distance);

  1083. 

  1084.     // the last frame to decode might have a different length

  1085.     if (sconf->samples != 0xFFFFFFFF)

  1086.         ctx->cur_frame_length = FFMIN(sconf->samples - ctx->frame_id * (uint64_t) sconf->frame_length,

  1087.                                       sconf->frame_length);

  1088.     else

  1089.         ctx->cur_frame_length = sconf->frame_length;

  1090. 

  1091.     // decode the frame data

  1092.     if ((invalid_frame = read_frame_data(ctx, ra_frame) < 0))

  1093.         av_log(ctx->avctx, AV_LOG_WARNING,

  1094.                "Reading frame data failed. Skipping RA unit.\n");

  1095. 

  1096.     ctx->frame_id++;

  1097. 

  1098.     // check for size of decoded data

  1099.     size = ctx->cur_frame_length * avctx->channels *

  1100.            (av_get_bits_per_sample_format(avctx->sample_fmt) >> 3);

  1101. 

  1102.     if (size > *data_size) {

  1103.         av_log(avctx, AV_LOG_ERROR, "Decoded data exceeds buffer size.\n");

  1104.         return -1;

  1105.     }

  1106. 

  1107.     *data_size = size;

  1108. 

  1109.     // transform decoded frame into output format

  1110.     #define INTERLEAVE_OUTPUT(bps)                                 \

  1111.     {                                                              \

  1112.         int##bps##_t *dest = (int##bps##_t*) data;                 \

  1113.         shift = bps - ctx->avctx->bits_per_raw_sample;             \

  1114.         for (sample = 0; sample < ctx->cur_frame_length; sample++) \

  1115.             for (c = 0; c < avctx->channels; c++)                  \

  1116.                 *dest++ = ctx->raw_samples[c][sample] << shift;    \

  1117.     }

  1118. 

  1119.     if (ctx->avctx->bits_per_raw_sample <= 16) {

  1120.         INTERLEAVE_OUTPUT(16)

  1121.     } else {

  1122.         INTERLEAVE_OUTPUT(32)

  1123.     }

  1124. 

  1125.     bytes_read = invalid_frame ? buffer_size :

  1126.                                  (get_bits_count(&ctx->gb) + 7) >> 3;

  1127. 

  1128.     return bytes_read;

  1129. }

  1130. 

  1131. 

  1132. /** Uninitializes the ALS decoder.

  1133.  */

  1134. static av_cold int decode_end(AVCodecContext *avctx)

  1135. {

  1136.     ALSDecContext *ctx = avctx->priv_data;

  1137. 

  1138.     av_freep(&ctx->sconf.chan_pos);

  1139. 

  1140.     av_freep(&ctx->use_ltp);

  1141.     av_freep(&ctx->ltp_lag);

  1142.     av_freep(&ctx->ltp_gain);

  1143.     av_freep(&ctx->ltp_gain_buffer);

  1144.     av_freep(&ctx->quant_cof);

  1145.     av_freep(&ctx->lpc_cof);

  1146.     av_freep(&ctx->prev_raw_samples);

  1147.     av_freep(&ctx->raw_samples);

  1148.     av_freep(&ctx->raw_buffer);

  1149. 

  1150.     return 0;

  1151. }

  1152. 

  1153. 

  1154. /** Initializes the ALS decoder.

  1155.  */

  1156. static av_cold int decode_init(AVCodecContext *avctx)

  1157. {

  1158.     unsigned int c;

  1159.     unsigned int channel_size;

  1160.     int num_buffers;

  1161.     ALSDecContext *ctx = avctx->priv_data;

  1162.     ALSSpecificConfig *sconf = &ctx->sconf;

  1163.     ctx->avctx = avctx;

  1164. 

  1165.     if (!avctx->extradata) {

  1166.         av_log(avctx, AV_LOG_ERROR, "Missing required ALS extradata.\n");

  1167.         return -1;

  1168.     }

  1169. 

  1170.     if (read_specific_config(ctx)) {

  1171.         av_log(avctx, AV_LOG_ERROR, "Reading ALSSpecificConfig failed.\n");

  1172.         decode_end(avctx);

  1173.         return -1;

  1174.     }

  1175. 

  1176.     if (check_specific_config(ctx)) {

  1177.         decode_end(avctx);

  1178.         return -1;

  1179.     }

  1180. 

  1181.     if (sconf->floating) {

  1182.         avctx->sample_fmt          = SAMPLE_FMT_FLT;

  1183.         avctx->bits_per_raw_sample = 32;

  1184.     } else {

  1185.         avctx->sample_fmt          = sconf->resolution > 1

  1186.                                      ? SAMPLE_FMT_S32 : SAMPLE_FMT_S16;

  1187.         avctx->bits_per_raw_sample = (sconf->resolution + 1) * 8;

  1188.     }

  1189. 

  1190.     // set lag value for long-term prediction

  1191.     ctx->ltp_lag_length = 8 + (avctx->sample_rate >=  96000) +

  1192.                               (avctx->sample_rate >= 192000);

  1193. 

  1194.     // allocate quantized parcor coefficient buffer

  1195.     num_buffers = sconf->mc_coding ? avctx->channels : 1;

  1196. 

  1197.     // allocate and assign lag and gain data buffer for ltp mode

  1198.     ctx->use_ltp         = av_mallocz(sizeof(*ctx->use_ltp)  * num_buffers);

  1199.     ctx->ltp_lag         = av_malloc (sizeof(*ctx->ltp_lag)  * num_buffers);

  1200.     ctx->ltp_gain        = av_malloc (sizeof(*ctx->ltp_gain) * num_buffers);

  1201.     ctx->ltp_gain_buffer = av_malloc (sizeof(*ctx->ltp_gain_buffer) *

  1202.                                       num_buffers * 5);

  1203. 

  1204.     if (!ctx->use_ltp  || !ctx->ltp_lag ||

  1205.         !ctx->ltp_gain || !ctx->ltp_gain_buffer) {

  1206.         av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1207.         decode_end(avctx);

  1208.         return AVERROR(ENOMEM);

  1209.     }

  1210. 

  1211.     for (c = 0; c < num_buffers; c++)

  1212.         ctx->ltp_gain[c] = ctx->ltp_gain_buffer + c * 5;

  1213. 

  1214.     avctx->frame_size = sconf->frame_length;

  1215.     channel_size      = sconf->frame_length + sconf->max_order;

  1216. 

  1217.     ctx->prev_raw_samples = av_malloc (sizeof(*ctx->prev_raw_samples) * sconf->max_order);

  1218.     ctx->raw_buffer       = av_mallocz(sizeof(*ctx->     raw_buffer)  * avctx->channels * channel_size);

  1219.     ctx->raw_samples      = av_malloc (sizeof(*ctx->     raw_samples) * avctx->channels);

  1220. 

  1221.     // allocate previous raw sample buffer

  1222.     if (!ctx->prev_raw_samples || !ctx->raw_buffer|| !ctx->raw_samples) {

  1223.         av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1224.         decode_end(avctx);

  1225.         return AVERROR(ENOMEM);

  1226.     }

  1227. 

  1228.     // assign raw samples buffers

  1229.     ctx->raw_samples[0] = ctx->raw_buffer + sconf->max_order;

  1230.     for (c = 1; c < avctx->channels; c++)

  1231.         ctx->raw_samples[c] = ctx->raw_samples[c - 1] + channel_size;

  1232. 

  1233.     return 0;

  1234. }

  1235. 

  1236. 

  1237. /** Flushes (resets) the frame ID after seeking.

  1238.  */

  1239. static av_cold void flush(AVCodecContext *avctx)

  1240. {

  1241.     ALSDecContext *ctx = avctx->priv_data;

  1242. 

  1243.     ctx->frame_id = 0;

  1244. }

  1245. 

  1246. 

  1247. AVCodec als_decoder = {

  1248.     "als",

  1249.     CODEC_TYPE_AUDIO,

  1250.     CODEC_ID_MP4ALS,

  1251.     sizeof(ALSDecContext),

  1252.     decode_init,

  1253.     NULL,

  1254.     decode_end,

  1255.     decode_frame,

  1256.     .flush = flush,

  1257.     .capabilities = CODEC_CAP_SUBFRAMES,

  1258.     .long_name = NULL_IF_CONFIG_SMALL("MPEG-4 Audio Lossless Coding (ALS)"),

  1259. };