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FFmpeg/libavcodec/alsdec.c

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  1. /*

  2.  * MPEG-4 ALS decoder

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

  4.  *

  5.  * This file is part of Libav.

  6.  *

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

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

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

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

  11.  *

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

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

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

  15.  * Lesser General Public License for more details.

  16.  *

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

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

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

  20.  */

  21. 

  22. /**

  23.  * @file

  24.  * MPEG-4 ALS decoder

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

  26.  */

  27. 

  28. #include <inttypes.h>

  29. 

  30. #include "avcodec.h"

  31. #include "bitstream.h"

  32. #include "mpeg4audio.h"

  33. #include "bytestream.h"

  34. #include "bgmc.h"

  35. #include "bswapdsp.h"

  36. #include "internal.h"

  37. #include "unary.h"

  38. 

  39. #include "libavutil/samplefmt.h"

  40. #include "libavutil/crc.h"

  41. 

  42. #include <stdint.h>

  43. 

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

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

  46.  *  by the encoder and stored in ALSSpecificConfig.

  47.  */

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

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

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

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

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

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

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

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

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

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

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

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

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

  61. };

  62. 

  63. 

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

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

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

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

  68.  */

  69. static const int16_t parcor_scaled_values[] = {

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  102. };

  103. 

  104. 

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

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

  107.  */

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

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

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

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

  112.     {88, 92, 96, 100}

  113. };

  114. 

  115. 

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

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

  118.  */

  119. static const int16_t mcc_weightings[] = {

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

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

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

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

  124. };

  125. 

  126. 

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

  128.  */

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  146. };

  147. 

  148. 

  149. enum RA_Flag {

  150.     RA_FLAG_NONE,

  151.     RA_FLAG_FRAMES,

  152.     RA_FLAG_HEADER

  153. };

  154. 

  155. 

  156. typedef struct ALSSpecificConfig {

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  179. } ALSSpecificConfig;

  180. 

  181. 

  182. typedef struct ALSChannelData {

  183.     int stop_flag;

  184.     int master_channel;

  185.     int time_diff_flag;

  186.     int time_diff_sign;

  187.     int time_diff_index;

  188.     int weighting[6];

  189. } ALSChannelData;

  190. 

  191. 

  192. typedef struct ALSDecContext {

  193.     AVCodecContext *avctx;

  194.     ALSSpecificConfig sconf;

  195.     BitstreamContext bc;

  196.     BswapDSPContext bdsp;

  197.     const AVCRC *crc_table;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  228. } ALSDecContext;

  229. 

  230. 

  231. typedef struct ALSBlockData {

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  247. } ALSBlockData;

  248. 

  249. 

  250. #ifdef DEBUG

  251. static av_cold void dprint_specific_config(ALSDecContext *ctx)

  252. {

  253.     AVCodecContext *avctx    = ctx->avctx;

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

  255. 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  274. }

  275. #else

  276. #define dprint_specific_config(x) do {} while(0)

  277. #endif

  278. 

  279. 

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

  281.  */

  282. static av_cold int read_specific_config(ALSDecContext *ctx)

  283. {

  284.     BitstreamContext bc;

  285.     uint64_t ht_size;

  286.     int i, config_offset;

  287.     MPEG4AudioConfig m4ac;

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

  289.     AVCodecContext *avctx    = ctx->avctx;

  290.     uint32_t als_id, header_size, trailer_size;

  291. 

  292.     bitstream_init8(&bc, avctx->extradata, avctx->extradata_size);

  293. 

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

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

  296. 

  297.     if (config_offset < 0)

  298.         return AVERROR_INVALIDDATA;

  299. 

  300.     bitstream_skip(&bc, config_offset);

  301. 

  302.     if (bitstream_bits_left(&bc) < (30 << 3))

  303.         return AVERROR_INVALIDDATA;

  304. 

  305.     // read the fixed items

  306.     als_id                      = bitstream_read(&bc, 32);

  307.     avctx->sample_rate          = m4ac.sample_rate;

  308.     bitstream_skip(&bc, 32); // sample rate already known

  309.     sconf->samples              = bitstream_read(&bc, 32);

  310.     avctx->channels             = m4ac.channels;

  311.     bitstream_skip(&bc, 16); // number of channels already known

  312.     bitstream_skip(&bc, 3);  // skip file_type

  313.     sconf->resolution           = bitstream_read(&bc, 3);

  314.     sconf->floating             = bitstream_read_bit(&bc);

  315.     sconf->msb_first            = bitstream_read_bit(&bc);

  316.     sconf->frame_length         = bitstream_read(&bc, 16) + 1;

  317.     sconf->ra_distance          = bitstream_read(&bc, 8);

  318.     sconf->ra_flag              = bitstream_read(&bc, 2);

  319.     sconf->adapt_order          = bitstream_read_bit(&bc);

  320.     sconf->coef_table           = bitstream_read(&bc, 2);

  321.     sconf->long_term_prediction = bitstream_read_bit(&bc);

  322.     sconf->max_order            = bitstream_read(&bc, 10);

  323.     sconf->block_switching      = bitstream_read(&bc, 2);

  324.     sconf->bgmc                 = bitstream_read_bit(&bc);

  325.     sconf->sb_part              = bitstream_read_bit(&bc);

  326.     sconf->joint_stereo         = bitstream_read_bit(&bc);

  327.     sconf->mc_coding            = bitstream_read_bit(&bc);

  328.     sconf->chan_config          = bitstream_read_bit(&bc);

  329.     sconf->chan_sort            = bitstream_read_bit(&bc);

  330.     sconf->crc_enabled          = bitstream_read_bit(&bc);

  331.     sconf->rlslms               = bitstream_read_bit(&bc);

  332.     bitstream_skip(&bc, 5);  // skip 5 reserved bits

  333.     bitstream_skip(&bc, 1);  // skip aux_data_enabled

  334. 

  335. 

  336.     // check for ALSSpecificConfig struct

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

  338.         return AVERROR_INVALIDDATA;

  339. 

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

  341. 

  342.     // read channel config

  343.     if (sconf->chan_config)

  344.         sconf->chan_config_info = bitstream_read(&bc, 16);

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

  346. 

  347. 

  348.     // read channel sorting

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

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

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

  352.         if (bitstream_bits_left(&bc) < bits_needed)

  353.             return AVERROR_INVALIDDATA;

  354. 

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

  356.             return AVERROR(ENOMEM);

  357. 

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

  359.             sconf->chan_pos[i] = bitstream_read(&bc, chan_pos_bits);

  360. 

  361.         bitstream_align(&bc);

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

  363.     } else {

  364.         sconf->chan_sort = 0;

  365.     }

  366. 

  367. 

  368.     // read fixed header and trailer sizes,

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

  370.     if (bitstream_bits_left(&bc) < 64)

  371.         return AVERROR_INVALIDDATA;

  372. 

  373.     header_size  = bitstream_read(&bc, 32);

  374.     trailer_size = bitstream_read(&bc, 32);

  375.     if (header_size  == 0xFFFFFFFF)

  376.         header_size  = 0;

  377.     if (trailer_size == 0xFFFFFFFF)

  378.         trailer_size = 0;

  379. 

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

  381. 

  382. 

  383.     // skip the header and trailer data

  384.     if (bitstream_bits_left(&bc) < ht_size)

  385.         return AVERROR_INVALIDDATA;

  386. 

  387.     if (ht_size > INT32_MAX)

  388.         return AVERROR_PATCHWELCOME;

  389. 

  390.     bitstream_skip(&bc, ht_size);

  391. 

  392. 

  393.     // initialize CRC calculation

  394.     if (sconf->crc_enabled) {

  395.         if (bitstream_bits_left(&bc) < 32)

  396.             return AVERROR_INVALIDDATA;

  397. 

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

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

  400.             ctx->crc       = 0xFFFFFFFF;

  401.             ctx->crc_org   = ~bitstream_read(&bc, 32);

  402.         } else

  403.             bitstream_skip(&bc, 32);

  404.     }

  405. 

  406. 

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

  408. 

  409.     dprint_specific_config(ctx);

  410. 

  411.     return 0;

  412. }

  413. 

  414. 

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

  416.  */

  417. static int check_specific_config(ALSDecContext *ctx)

  418. {

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

  420.     int error = 0;

  421. 

  422.     // report unsupported feature and set error value

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

  424.     {                                                   \

  425.         if (cond) {                                     \

  426.             avpriv_report_missing_feature(ctx->avctx,   \

  427.                                           str);         \

  428.             error = errval;                             \

  429.         }                                               \

  430.     }

  431. 

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

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

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

  435. 

  436.     return error;

  437. }

  438. 

  439. 

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

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

  442.  */

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

  444.                           unsigned int div, unsigned int **div_blocks,

  445.                           unsigned int *num_blocks)

  446. {

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

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

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

  450.         n   *= 2;

  451.         div += 1;

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

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

  454.     } else {

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

  456.         // (bit implicitly not set)

  457.         **div_blocks = div;

  458.         (*div_blocks)++;

  459.         (*num_blocks)++;

  460.     }

  461. }

  462. 

  463. 

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

  465.  */

  466. static int32_t decode_rice(BitstreamContext *bc, unsigned int k)

  467. {

  468.     int max = bitstream_bits_left(bc) - k;

  469.     int q   = get_unary(bc, 0, max);

  470.     int r   = k ? bitstream_read_bit(bc) : !(q & 1);

  471. 

  472.     if (k > 1) {

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

  474.         q  += bitstream_read(bc, k - 1);

  475.     } else if (!k) {

  476.         q >>= 1;

  477.     }

  478.     return r ? q : ~q;

  479. }

  480. 

  481. 

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

  483.  */

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

  485. {

  486.     int i, j;

  487. 

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

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

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

  491.         cof[i]  += tmp1;

  492.     }

  493.     if (i == j)

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

  495. 

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

  497. }

  498. 

  499. 

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

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

  502.  *  actual number of samples.

  503.  */

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

  505.                             uint32_t *bs_info)

  506. {

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

  508.     BitstreamContext *bc         = &ctx->bc;

  509.     unsigned int *ptr_div_blocks = div_blocks;

  510.     unsigned int b;

  511. 

  512.     if (sconf->block_switching) {

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

  514.         *bs_info = bitstream_read(bc, bs_info_len);

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

  516.     }

  517. 

  518.     ctx->num_blocks = 0;

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

  520. 

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

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

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

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

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

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

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

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

  529.     // codec RM22 revision 2.

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

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

  532.     // of 14496-3.

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

  534.     // frame.

  535. 

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

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

  538. 

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

  540.         unsigned int remaining = ctx->cur_frame_length;

  541. 

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

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

  544.                 div_blocks[b] = remaining;

  545.                 ctx->num_blocks = b + 1;

  546.                 break;

  547.             }

  548. 

  549.             remaining -= div_blocks[b];

  550.         }

  551.     }

  552. }

  553. 

  554. 

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

  556.  */

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

  558. {

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

  560.     AVCodecContext *avctx    = ctx->avctx;

  561.     BitstreamContext *bc     = &ctx->bc;

  562. 

  563.     *bd->raw_samples = 0;

  564.     *bd->const_block = bitstream_read_bit(bc);  // 1 = constant value, 0 = zero block (silence)

  565.     bd->js_blocks    = bitstream_read_bit(bc);

  566. 

  567.     // skip 5 reserved bits

  568.     bitstream_skip(bc, 5);

  569. 

  570.     if (*bd->const_block) {

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

  572.         *bd->raw_samples = bitstream_read_signed(bc, const_val_bits);

  573.     }

  574. 

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

  576.     *bd->const_block = 1;

  577. }

  578. 

  579. 

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

  581.  */

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

  583. {

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

  585.     int32_t  val = *bd->raw_samples;

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

  587. 

  588.     // write raw samples into buffer

  589.     for (; smp; smp--)

  590.         *dst++ = val;

  591. }

  592. 

  593. 

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

  595.  */

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

  597. {

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

  599.     AVCodecContext *avctx    = ctx->avctx;

  600.     BitstreamContext *bc     = &ctx->bc;

  601.     unsigned int k;

  602.     unsigned int s[8];

  603.     unsigned int sx[8];

  604.     unsigned int sub_blocks, log2_sub_blocks, sb_length;

  605.     unsigned int start      = 0;

  606.     unsigned int opt_order;

  607.     int          sb;

  608.     int32_t      *quant_cof = bd->quant_cof;

  609.     int32_t      *current_res;

  610. 

  611. 

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

  613.     *bd->const_block = 0;

  614. 

  615.     *bd->opt_order  = 1;

  616.     bd->js_blocks   = bitstream_read_bit(bc);

  617. 

  618.     opt_order       = *bd->opt_order;

  619. 

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

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

  622.         log2_sub_blocks = 0;

  623.     } else {

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

  625.             log2_sub_blocks = bitstream_read(bc, 2);

  626.         else

  627.             log2_sub_blocks = 2 * bitstream_read_bit(bc);

  628.     }

  629. 

  630.     sub_blocks = 1 << log2_sub_blocks;

  631. 

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

  633.     // block_length must be evenly divisible by sub_blocks

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

  635.         av_log(avctx, AV_LOG_WARNING,

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

  637.         return AVERROR_INVALIDDATA;

  638.     }

  639. 

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

  641. 

  642.     if (sconf->bgmc) {

  643.         s[0] = bitstream_read(bc, 8 + (sconf->resolution > 1));

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

  645.             s[k] = s[k - 1] + decode_rice(bc, 2);

  646. 

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

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

  649.             s [k] >>= 4;

  650.         }

  651.     } else {

  652.         s[0] = bitstream_read(bc, 4 + (sconf->resolution > 1));

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

  654.             s[k] = s[k - 1] + decode_rice(bc, 0);

  655.     }

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

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

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

  659.             return AVERROR_INVALIDDATA;

  660.         }

  661. 

  662.     if (bitstream_read_bit(bc))

  663.         *bd->shift_lsbs = bitstream_read(bc, 4) + 1;

  664. 

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

  666. 

  667. 

  668.     if (!sconf->rlslms) {

  669.         if (sconf->adapt_order && sconf->max_order) {

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

  671.                                                 2, sconf->max_order + 1));

  672.             *bd->opt_order       = bitstream_read(bc, opt_order_length);

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

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

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

  676.                 return AVERROR_INVALIDDATA;

  677.             }

  678.         } else {

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

  680.         }

  681. 

  682.         opt_order = *bd->opt_order;

  683. 

  684.         if (opt_order) {

  685.             int add_base;

  686. 

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

  688.                 add_base = 0x7F;

  689. 

  690.                 // read coefficient 0

  691.                 quant_cof[0] = 32 * parcor_scaled_values[bitstream_read(bc, 7)];

  692. 

  693.                 // read coefficient 1

  694.                 if (opt_order > 1)

  695.                     quant_cof[1] = -32 * parcor_scaled_values[bitstream_read(bc, 7)];

  696. 

  697.                 // read coefficients 2 to opt_order

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

  699.                     quant_cof[k] = bitstream_read(bc, 7);

  700.             } else {

  701.                 int k_max;

  702.                 add_base = 1;

  703. 

  704.                 // read coefficient 0 to 19

  705.                 k_max = FFMIN(opt_order, 20);

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

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

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

  709.                     quant_cof[k] = decode_rice(bc, rice_param) + offset;

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

  711.                         av_log(avctx, AV_LOG_ERROR,

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

  713.                                quant_cof[k]);

  714.                         return AVERROR_INVALIDDATA;

  715.                     }

  716.                 }

  717. 

  718.                 // read coefficients 20 to 126

  719.                 k_max = FFMIN(opt_order, 127);

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

  721.                     quant_cof[k] = decode_rice(bc, 2) + (k & 1);

  722. 

  723.                 // read coefficients 127 to opt_order

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

  725.                     quant_cof[k] = decode_rice(bc, 1);

  726. 

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

  728. 

  729.                 if (opt_order > 1)

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

  731.             }

  732. 

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

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

  735.         }

  736.     }

  737. 

  738.     // read LTP gain and lag values

  739.     if (sconf->long_term_prediction) {

  740.         *bd->use_ltp = bitstream_read_bit(bc);

  741. 

  742.         if (*bd->use_ltp) {

  743.             int r, c;

  744. 

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

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

  747. 

  748.             r                 = get_unary(bc, 0, 3);

  749.             c                 = bitstream_read(bc, 2);

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

  751. 

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

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

  754. 

  755.             *bd->ltp_lag      = bitstream_read(bc, ctx->ltp_lag_length);

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

  757.         }

  758.     }

  759. 

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

  761.     if (bd->ra_block) {

  762.         if (opt_order)

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

  764.         if (opt_order > 1)

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

  766.         if (opt_order > 2)

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

  768. 

  769.         start = FFMIN(opt_order, 3);

  770.     }

  771. 

  772.     // read all residuals

  773.     if (sconf->bgmc) {

  774.         int          delta[8];

  775.         unsigned int k    [8];

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

  777. 

  778.         // read most significant bits

  779.         unsigned int high;

  780.         unsigned int low;

  781.         unsigned int value;

  782. 

  783.         ff_bgmc_decode_init(bc, &high, &low, &value);

  784. 

  785.         current_res = bd->raw_samples + start;

  786. 

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

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

  789. 

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

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

  792. 

  793.             ff_bgmc_decode(bc, sb_len, current_res, delta[sb], sx[sb], &high,

  794.                            &low, &value, ctx->bgmc_lut, ctx->bgmc_lut_status);

  795. 

  796.             current_res += sb_len;

  797.         }

  798. 

  799.         ff_bgmc_decode_end(bc);

  800. 

  801. 

  802.         // read least significant bits and tails

  803.         current_res = bd->raw_samples + start;

  804. 

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

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

  807.             unsigned int cur_k         = k[sb];

  808.             unsigned int cur_s         = s[sb];

  809. 

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

  811.                 int32_t res = *current_res;

  812. 

  813.                 if (res == cur_tail_code) {

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

  815.                                           << (5 - delta[sb]);

  816. 

  817.                     res = decode_rice(bc, cur_s);

  818. 

  819.                     if (res >= 0) {

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

  821.                     } else {

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

  823.                     }

  824.                 } else {

  825.                     if (res > cur_tail_code)

  826.                         res--;

  827. 

  828.                     if (res & 1)

  829.                         res = -res;

  830. 

  831.                     res >>= 1;

  832. 

  833.                     if (cur_k) {

  834.                         res <<= cur_k;

  835.                         res  |= bitstream_read(bc, cur_k);

  836.                     }

  837.                 }

  838. 

  839.                 *current_res++ = res;

  840.             }

  841.         }

  842.     } else {

  843.         current_res = bd->raw_samples + start;

  844. 

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

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

  847.                 *current_res++ = decode_rice(bc, s[sb]);

  848.      }

  849. 

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

  851.         bitstream_align(bc);

  852. 

  853.     return 0;

  854. }

  855. 

  856. 

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

  858.  */

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

  860. {

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

  862.     unsigned int block_length = bd->block_length;

  863.     unsigned int smp = 0;

  864.     unsigned int k;

  865.     int opt_order             = *bd->opt_order;

  866.     int sb;

  867.     int64_t y;

  868.     int32_t *quant_cof        = bd->quant_cof;

  869.     int32_t *lpc_cof          = bd->lpc_cof;

  870.     int32_t *raw_samples      = bd->raw_samples;

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

  872.     int32_t *lpc_cof_reversed = ctx->lpc_cof_reversed_buffer;

  873. 

  874.     // reverse long-term prediction

  875.     if (*bd->use_ltp) {

  876.         int ltp_smp;

  877. 

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

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

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

  881.             int end    = center + 3;

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

  883.             int base;

  884. 

  885.             y = 1 << 6;

  886. 

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

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

  889. 

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

  891.         }

  892.     }

  893. 

  894.     // reconstruct all samples from residuals

  895.     if (bd->ra_block) {

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

  897.             y = 1 << 19;

  898. 

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

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

  901. 

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

  903.             parcor_to_lpc(smp, quant_cof, lpc_cof);

  904.         }

  905.     } else {

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

  907.             parcor_to_lpc(k, quant_cof, lpc_cof);

  908. 

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

  910.         if (*bd->store_prev_samples)

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

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

  913. 

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

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

  916.             int32_t *left, *right;

  917. 

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

  919.                 left  = raw_samples;

  920.                 right = bd->raw_other;

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

  922.                 left  = bd->raw_other;

  923.                 right = raw_samples;

  924.             }

  925. 

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

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

  928.         }

  929. 

  930.         // reconstruct shifted signal

  931.         if (*bd->shift_lsbs)

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

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

  934.     }

  935. 

  936.     // reverse linear prediction coefficients for efficiency

  937.     lpc_cof = lpc_cof + opt_order;

  938. 

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

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

  941. 

  942.     // reconstruct raw samples

  943.     raw_samples = bd->raw_samples + smp;

  944.     lpc_cof     = lpc_cof_reversed + opt_order;

  945. 

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

  947.         y = 1 << 19;

  948. 

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

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

  951. 

  952.         *raw_samples -= y >> 20;

  953.     }

  954. 

  955.     raw_samples = bd->raw_samples;

  956. 

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

  958.     if (*bd->store_prev_samples)

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

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

  961. 

  962.     return 0;

  963. }

  964. 

  965. 

  966. /** Read the block data.

  967.  */

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

  969. {

  970.     int ret = 0;

  971.     BitstreamContext *bc = &ctx->bc;

  972. 

  973.     *bd->shift_lsbs = 0;

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

  975.     if (bitstream_read_bit(bc)) {

  976.         ret = read_var_block_data(ctx, bd);

  977.     } else {

  978.         read_const_block_data(ctx, bd);

  979.     }

  980. 

  981.     return ret;

  982. }

  983. 

  984. 

  985. /** Decode the block data.

  986.  */

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

  988. {

  989.     unsigned int smp;

  990.     int ret = 0;

  991. 

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

  993.     if (*bd->const_block)

  994.         decode_const_block_data(ctx, bd);

  995.     else

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

  997. 

  998.     if (ret < 0)

  999.         return ret;

  1000. 

  1001.     // TODO: read RLSLMS extension data

  1002. 

  1003.     if (*bd->shift_lsbs)

  1004.         for (smp = 0; smp < bd->block_length; smp++)

  1005.             bd->raw_samples[smp] <<= *bd->shift_lsbs;

  1006. 

  1007.     return 0;

  1008. }

  1009. 

  1010. 

  1011. /** Read and decode block data successively.

  1012.  */

  1013. static int read_decode_block(ALSDecContext *ctx, ALSBlockData *bd)

  1014. {

  1015.     int ret;

  1016. 

  1017.     if ((ret = read_block(ctx, bd)) < 0)

  1018.         return ret;

  1019. 

  1020.     return decode_block(ctx, bd);

  1021. }

  1022. 

  1023. 

  1024. /** Compute the number of samples left to decode for the current frame and

  1025.  *  sets these samples to zero.

  1026.  */

  1027. static void zero_remaining(unsigned int b, unsigned int b_max,

  1028.                            const unsigned int *div_blocks, int32_t *buf)

  1029. {

  1030.     unsigned int count = 0;

  1031. 

  1032.     for (; b < b_max; b++)

  1033.         count += div_blocks[b];

  1034. 

  1035.     if (count)

  1036.         memset(buf, 0, sizeof(*buf) * count);

  1037. }

  1038. 

  1039. 

  1040. /** Decode blocks independently.

  1041.  */

  1042. static int decode_blocks_ind(ALSDecContext *ctx, unsigned int ra_frame,

  1043.                              unsigned int c, const unsigned int *div_blocks,

  1044.                              unsigned int *js_blocks)

  1045. {

  1046.     int ret;

  1047.     unsigned int b;

  1048.     ALSBlockData bd = { 0 };

  1049. 

  1050.     bd.ra_block         = ra_frame;

  1051.     bd.const_block      = ctx->const_block;

  1052.     bd.shift_lsbs       = ctx->shift_lsbs;

  1053.     bd.opt_order        = ctx->opt_order;

  1054.     bd.store_prev_samples = ctx->store_prev_samples;

  1055.     bd.use_ltp          = ctx->use_ltp;

  1056.     bd.ltp_lag          = ctx->ltp_lag;

  1057.     bd.ltp_gain         = ctx->ltp_gain[0];

  1058.     bd.quant_cof        = ctx->quant_cof[0];

  1059.     bd.lpc_cof          = ctx->lpc_cof[0];

  1060.     bd.prev_raw_samples = ctx->prev_raw_samples;

  1061.     bd.raw_samples      = ctx->raw_samples[c];

  1062. 

  1063. 

  1064.     for (b = 0; b < ctx->num_blocks; b++) {

  1065.         bd.block_length     = div_blocks[b];

  1066. 

  1067.         if ((ret = read_decode_block(ctx, &bd)) < 0) {

  1068.             // damaged block, write zero for the rest of the frame

  1069.             zero_remaining(b, ctx->num_blocks, div_blocks, bd.raw_samples);

  1070.             return ret;

  1071.         }

  1072.         bd.raw_samples += div_blocks[b];

  1073.         bd.ra_block     = 0;

  1074.     }

  1075. 

  1076.     return 0;

  1077. }

  1078. 

  1079. 

  1080. /** Decode blocks dependently.

  1081.  */

  1082. static int decode_blocks(ALSDecContext *ctx, unsigned int ra_frame,

  1083.                          unsigned int c, const unsigned int *div_blocks,

  1084.                          unsigned int *js_blocks)

  1085. {

  1086.     ALSSpecificConfig *sconf = &ctx->sconf;

  1087.     unsigned int offset = 0;

  1088.     unsigned int b;

  1089.     int ret;

  1090.     ALSBlockData bd[2] = { { 0 } };

  1091. 

  1092.     bd[0].ra_block         = ra_frame;

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

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

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

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

  1097.     bd[0].use_ltp          = ctx->use_ltp;

  1098.     bd[0].ltp_lag          = ctx->ltp_lag;

  1099.     bd[0].ltp_gain         = ctx->ltp_gain[0];

  1100.     bd[0].quant_cof        = ctx->quant_cof[0];

  1101.     bd[0].lpc_cof          = ctx->lpc_cof[0];

  1102.     bd[0].prev_raw_samples = ctx->prev_raw_samples;

  1103.     bd[0].js_blocks        = *js_blocks;

  1104. 

  1105.     bd[1].ra_block         = ra_frame;

  1106.     bd[1].const_block      = ctx->const_block;

  1107.     bd[1].shift_lsbs       = ctx->shift_lsbs;

  1108.     bd[1].opt_order        = ctx->opt_order;

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

  1110.     bd[1].use_ltp          = ctx->use_ltp;

  1111.     bd[1].ltp_lag          = ctx->ltp_lag;

  1112.     bd[1].ltp_gain         = ctx->ltp_gain[0];

  1113.     bd[1].quant_cof        = ctx->quant_cof[0];

  1114.     bd[1].lpc_cof          = ctx->lpc_cof[0];

  1115.     bd[1].prev_raw_samples = ctx->prev_raw_samples;

  1116.     bd[1].js_blocks        = *(js_blocks + 1);

  1117. 

  1118.     // decode all blocks

  1119.     for (b = 0; b < ctx->num_blocks; b++) {

  1120.         unsigned int s;

  1121. 

  1122.         bd[0].block_length = div_blocks[b];

  1123.         bd[1].block_length = div_blocks[b];

  1124. 

  1125.         bd[0].raw_samples  = ctx->raw_samples[c    ] + offset;

  1126.         bd[1].raw_samples  = ctx->raw_samples[c + 1] + offset;

  1127. 

  1128.         bd[0].raw_other    = bd[1].raw_samples;

  1129.         bd[1].raw_other    = bd[0].raw_samples;

  1130. 

  1131.         if ((ret = read_decode_block(ctx, &bd[0])) < 0 ||

  1132.             (ret = read_decode_block(ctx, &bd[1])) < 0)

  1133.             goto fail;

  1134. 

  1135.         // reconstruct joint-stereo blocks

  1136.         if (bd[0].js_blocks) {

  1137.             if (bd[1].js_blocks)

  1138.                 av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel pair!\n");

  1139. 

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

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

  1142.         } else if (bd[1].js_blocks) {

  1143.             for (s = 0; s < div_blocks[b]; s++)

  1144.                 bd[1].raw_samples[s] = bd[1].raw_samples[s] + bd[0].raw_samples[s];

  1145.         }

  1146. 

  1147.         offset  += div_blocks[b];

  1148.         bd[0].ra_block = 0;

  1149.         bd[1].ra_block = 0;

  1150.     }

  1151. 

  1152.     // store carryover raw samples,

  1153.     // the others channel raw samples are stored by the calling function.

  1154.     memmove(ctx->raw_samples[c] - sconf->max_order,

  1155.             ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1156.             sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1157. 

  1158.     return 0;

  1159. fail:

  1160.     // damaged block, write zero for the rest of the frame

  1161.     zero_remaining(b, ctx->num_blocks, div_blocks, bd[0].raw_samples);

  1162.     zero_remaining(b, ctx->num_blocks, div_blocks, bd[1].raw_samples);

  1163.     return ret;

  1164. }

  1165. 

  1166. static inline int als_weighting(BitstreamContext *bc, int k, int off)

  1167. {

  1168.     int idx = av_clip(decode_rice(bc, k) + off,

  1169.                       0, FF_ARRAY_ELEMS(mcc_weightings) - 1);

  1170.     return mcc_weightings[idx];

  1171. }

  1172. 

  1173. /** Read the channel data.

  1174.   */

  1175. static int read_channel_data(ALSDecContext *ctx, ALSChannelData *cd, int c)

  1176. {

  1177.     BitstreamContext *bc    = &ctx->bc;

  1178.     ALSChannelData *current = cd;

  1179.     unsigned int channels   = ctx->avctx->channels;

  1180.     int entries             = 0;

  1181. 

  1182.     while (entries < channels && !(current->stop_flag = bitstream_read_bit(bc))) {

  1183.         current->master_channel = bitstream_read(bc, av_ceil_log2(channels));

  1184. 

  1185.         if (current->master_channel >= channels) {

  1186.             av_log(ctx->avctx, AV_LOG_ERROR, "Invalid master channel!\n");

  1187.             return AVERROR_INVALIDDATA;

  1188.         }

  1189. 

  1190.         if (current->master_channel != c) {

  1191.             current->time_diff_flag = bitstream_read_bit(bc);

  1192.             current->weighting[0]   = als_weighting(bc, 1, 16);

  1193.             current->weighting[1]   = als_weighting(bc, 2, 14);

  1194.             current->weighting[2]   = als_weighting(bc, 1, 16);

  1195. 

  1196.             if (current->time_diff_flag) {

  1197.                 current->weighting[3] = als_weighting(bc, 1, 16);

  1198.                 current->weighting[4] = als_weighting(bc, 1, 16);

  1199.                 current->weighting[5] = als_weighting(bc, 1, 16);

  1200. 

  1201.                 current->time_diff_sign  = bitstream_read_bit(bc);

  1202.                 current->time_diff_index = bitstream_read(bc, ctx->ltp_lag_length - 3) + 3;

  1203.             }

  1204.         }

  1205. 

  1206.         current++;

  1207.         entries++;

  1208.     }

  1209. 

  1210.     if (entries == channels) {

  1211.         av_log(ctx->avctx, AV_LOG_ERROR, "Damaged channel data!\n");

  1212.         return AVERROR_INVALIDDATA;

  1213.     }

  1214. 

  1215.     bitstream_align(bc);

  1216.     return 0;

  1217. }

  1218. 

  1219. 

  1220. /** Recursively reverts the inter-channel correlation for a block.

  1221.  */

  1222. static int revert_channel_correlation(ALSDecContext *ctx, ALSBlockData *bd,

  1223.                                        ALSChannelData **cd, int *reverted,

  1224.                                        unsigned int offset, int c)

  1225. {

  1226.     ALSChannelData *ch = cd[c];

  1227.     unsigned int   dep = 0;

  1228.     unsigned int channels = ctx->avctx->channels;

  1229.     unsigned int channel_size = ctx->sconf.frame_length + ctx->sconf.max_order;

  1230. 

  1231.     if (reverted[c])

  1232.         return 0;

  1233. 

  1234.     reverted[c] = 1;

  1235. 

  1236.     while (dep < channels && !ch[dep].stop_flag) {

  1237.         revert_channel_correlation(ctx, bd, cd, reverted, offset,

  1238.                                    ch[dep].master_channel);

  1239. 

  1240.         dep++;

  1241.     }

  1242. 

  1243.     if (dep == channels) {

  1244.         av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel correlation!\n");

  1245.         return AVERROR_INVALIDDATA;

  1246.     }

  1247. 

  1248.     bd->const_block = ctx->const_block + c;

  1249.     bd->shift_lsbs  = ctx->shift_lsbs + c;

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

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

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

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

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

  1255.     bd->lpc_cof     = ctx->lpc_cof[c];

  1256.     bd->quant_cof   = ctx->quant_cof[c];

  1257.     bd->raw_samples = ctx->raw_samples[c] + offset;

  1258. 

  1259.     dep = 0;

  1260.     while (!ch[dep].stop_flag) {

  1261.         ptrdiff_t smp;

  1262.         ptrdiff_t begin = 1;

  1263.         ptrdiff_t end   = bd->block_length - 1;

  1264.         int64_t y;

  1265.         int32_t *master = ctx->raw_samples[ch[dep].master_channel] + offset;

  1266. 

  1267.         if (ch[dep].time_diff_flag) {

  1268.             int t = ch[dep].time_diff_index;

  1269. 

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

  1271.                 t      = -t;

  1272.                 begin -= t;

  1273.             } else {

  1274.                 end   -= t;

  1275.             }

  1276. 

  1277.             if (FFMIN(begin - 1, begin - 1 + t) < ctx->raw_buffer - master ||

  1278.                 FFMAX(end   + 1,   end + 1 + t) > ctx->raw_buffer + channels * channel_size - master) {

  1279.                 av_log(ctx->avctx, AV_LOG_ERROR,

  1280.                        "sample pointer range [%p, %p] not contained in raw_buffer [%p, %p].\n",

  1281.                        master + FFMIN(begin - 1, begin - 1 + t), master + FFMAX(end + 1,   end + 1 + t),

  1282.                        ctx->raw_buffer, ctx->raw_buffer + channels * channel_size);

  1283.                 return AVERROR_INVALIDDATA;

  1284.             }

  1285. 

  1286.             for (smp = begin; smp < end; smp++) {

  1287.                 y  = (1 << 6) +

  1288.                      MUL64(ch[dep].weighting[0], master[smp - 1    ]) +

  1289.                      MUL64(ch[dep].weighting[1], master[smp        ]) +

  1290.                      MUL64(ch[dep].weighting[2], master[smp + 1    ]) +

  1291.                      MUL64(ch[dep].weighting[3], master[smp - 1 + t]) +

  1292.                      MUL64(ch[dep].weighting[4], master[smp     + t]) +

  1293.                      MUL64(ch[dep].weighting[5], master[smp + 1 + t]);

  1294. 

  1295.                 bd->raw_samples[smp] += y >> 7;

  1296.             }

  1297.         } else {

  1298. 

  1299.             if (begin - 1 < ctx->raw_buffer - master ||

  1300.                 end   + 1 > ctx->raw_buffer + channels * channel_size - master) {

  1301.                 av_log(ctx->avctx, AV_LOG_ERROR,

  1302.                        "sample pointer range [%p, %p] not contained in raw_buffer [%p, %p].\n",

  1303.                        master + begin - 1, master + end + 1,

  1304.                        ctx->raw_buffer, ctx->raw_buffer + channels * channel_size);

  1305.                 return AVERROR_INVALIDDATA;

  1306.             }

  1307. 

  1308.             for (smp = begin; smp < end; smp++) {

  1309.                 y  = (1 << 6) +

  1310.                      MUL64(ch[dep].weighting[0], master[smp - 1]) +

  1311.                      MUL64(ch[dep].weighting[1], master[smp    ]) +

  1312.                      MUL64(ch[dep].weighting[2], master[smp + 1]);

  1313. 

  1314.                 bd->raw_samples[smp] += y >> 7;

  1315.             }

  1316.         }

  1317. 

  1318.         dep++;

  1319.     }

  1320. 

  1321.     return 0;

  1322. }

  1323. 

  1324. 

  1325. /** Read the frame data.

  1326.  */

  1327. static int read_frame_data(ALSDecContext *ctx, unsigned int ra_frame)

  1328. {

  1329.     ALSSpecificConfig *sconf = &ctx->sconf;

  1330.     AVCodecContext *avctx    = ctx->avctx;

  1331.     BitstreamContext *bc     = &ctx->bc;

  1332.     unsigned int div_blocks[32];                ///< block sizes.

  1333.     unsigned int c;

  1334.     unsigned int js_blocks[2];

  1335.     uint32_t bs_info = 0;

  1336.     int ret;

  1337. 

  1338.     // skip the size of the ra unit if present in the frame

  1339.     if (sconf->ra_flag == RA_FLAG_FRAMES && ra_frame)

  1340.         bitstream_skip(bc, 32);

  1341. 

  1342.     if (sconf->mc_coding && sconf->joint_stereo) {

  1343.         ctx->js_switch = bitstream_read_bit(bc);

  1344.         bitstream_align(bc);

  1345.     }

  1346. 

  1347.     if (!sconf->mc_coding || ctx->js_switch) {

  1348.         int independent_bs = !sconf->joint_stereo;

  1349. 

  1350.         for (c = 0; c < avctx->channels; c++) {

  1351.             js_blocks[0] = 0;

  1352.             js_blocks[1] = 0;

  1353. 

  1354.             get_block_sizes(ctx, div_blocks, &bs_info);

  1355. 

  1356.             // if joint_stereo and block_switching is set, independent decoding

  1357.             // is signaled via the first bit of bs_info

  1358.             if (sconf->joint_stereo && sconf->block_switching)

  1359.                 if (bs_info >> 31)

  1360.                     independent_bs = 2;

  1361. 

  1362.             // if this is the last channel, it has to be decoded independently

  1363.             if (c == avctx->channels - 1)

  1364.                 independent_bs = 1;

  1365. 

  1366.             if (independent_bs) {

  1367.                 ret = decode_blocks_ind(ctx, ra_frame, c,

  1368.                                         div_blocks, js_blocks);

  1369.                 if (ret < 0)

  1370.                     return ret;

  1371.                 independent_bs--;

  1372.             } else {

  1373.                 ret = decode_blocks(ctx, ra_frame, c, div_blocks, js_blocks);

  1374.                 if (ret < 0)

  1375.                     return ret;

  1376. 

  1377.                 c++;

  1378.             }

  1379. 

  1380.             // store carryover raw samples

  1381.             memmove(ctx->raw_samples[c] - sconf->max_order,

  1382.                     ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1383.                     sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1384.         }

  1385.     } else { // multi-channel coding

  1386.         ALSBlockData   bd = { 0 };

  1387.         int            b, ret;

  1388.         int            *reverted_channels = ctx->reverted_channels;

  1389.         unsigned int   offset             = 0;

  1390. 

  1391.         for (c = 0; c < avctx->channels; c++)

  1392.             if (ctx->chan_data[c] < ctx->chan_data_buffer) {

  1393.                 av_log(ctx->avctx, AV_LOG_ERROR, "Invalid channel data!\n");

  1394.                 return AVERROR_INVALIDDATA;

  1395.             }

  1396. 

  1397.         memset(reverted_channels, 0, sizeof(*reverted_channels) * avctx->channels);

  1398. 

  1399.         bd.ra_block         = ra_frame;

  1400.         bd.prev_raw_samples = ctx->prev_raw_samples;

  1401. 

  1402.         get_block_sizes(ctx, div_blocks, &bs_info);

  1403. 

  1404.         for (b = 0; b < ctx->num_blocks; b++) {

  1405.             bd.block_length = div_blocks[b];

  1406.             if (bd.block_length <= 0) {

  1407.                 av_log(ctx->avctx, AV_LOG_WARNING,

  1408.                        "Invalid block length %u in channel data!\n",

  1409.                        bd.block_length);

  1410.                 continue;

  1411.             }

  1412. 

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

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

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

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

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

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

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

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

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

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

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

  1424.                 bd.raw_other   = NULL;

  1425. 

  1426.                 if ((ret = read_block(ctx, &bd)) < 0)

  1427.                     return ret;

  1428.                 if ((ret = read_channel_data(ctx, ctx->chan_data[c], c)) < 0)

  1429.                     return ret;

  1430.             }

  1431. 

  1432.             for (c = 0; c < avctx->channels; c++) {

  1433.                 ret = revert_channel_correlation(ctx, &bd, ctx->chan_data,

  1434.                                                  reverted_channels, offset, c);

  1435.                 if (ret < 0)

  1436.                     return ret;

  1437.             }

  1438.             for (c = 0; c < avctx->channels; c++) {

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

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

  1441.                 bd.opt_order   = ctx->opt_order + c;

  1442.                 bd.store_prev_samples = ctx->store_prev_samples + c;

  1443.                 bd.use_ltp     = ctx->use_ltp + c;

  1444.                 bd.ltp_lag     = ctx->ltp_lag + c;

  1445.                 bd.ltp_gain    = ctx->ltp_gain[c];

  1446.                 bd.lpc_cof     = ctx->lpc_cof[c];

  1447.                 bd.quant_cof   = ctx->quant_cof[c];

  1448.                 bd.raw_samples = ctx->raw_samples[c] + offset;

  1449.                 if ((ret = decode_block(ctx, &bd)) < 0)

  1450.                     return ret;

  1451.             }

  1452. 

  1453.             memset(reverted_channels, 0, avctx->channels * sizeof(*reverted_channels));

  1454.             offset      += div_blocks[b];

  1455.             bd.ra_block  = 0;

  1456.         }

  1457. 

  1458.         // store carryover raw samples

  1459.         for (c = 0; c < avctx->channels; c++)

  1460.             memmove(ctx->raw_samples[c] - sconf->max_order,

  1461.                     ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1462.                     sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1463.     }

  1464. 

  1465.     // TODO: read_diff_float_data

  1466. 

  1467.     return 0;

  1468. }

  1469. 

  1470. 

  1471. /** Decode an ALS frame.

  1472.  */

  1473. static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr,

  1474.                         AVPacket *avpkt)

  1475. {

  1476.     ALSDecContext *ctx       = avctx->priv_data;

  1477.     AVFrame *frame           = data;

  1478.     ALSSpecificConfig *sconf = &ctx->sconf;

  1479.     const uint8_t *buffer    = avpkt->data;

  1480.     int buffer_size          = avpkt->size;

  1481.     int invalid_frame, ret;

  1482.     unsigned int c, sample, ra_frame, bytes_read, shift;

  1483. 

  1484.     bitstream_init8(&ctx->bc, buffer, buffer_size);

  1485. 

  1486.     // In the case that the distance between random access frames is set to zero

  1487.     // (sconf->ra_distance == 0) no frame is treated as a random access frame.

  1488.     // For the first frame, if prediction is used, all samples used from the

  1489.     // previous frame are assumed to be zero.

  1490.     ra_frame = sconf->ra_distance && !(ctx->frame_id % sconf->ra_distance);

  1491. 

  1492.     // the last frame to decode might have a different length

  1493.     if (sconf->samples != 0xFFFFFFFF)

  1494.         ctx->cur_frame_length = FFMIN(sconf->samples - ctx->frame_id * (uint64_t) sconf->frame_length,

  1495.                                       sconf->frame_length);

  1496.     else

  1497.         ctx->cur_frame_length = sconf->frame_length;

  1498. 

  1499.     // decode the frame data

  1500.     if ((invalid_frame = read_frame_data(ctx, ra_frame)) < 0)

  1501.         av_log(ctx->avctx, AV_LOG_WARNING,

  1502.                "Reading frame data failed. Skipping RA unit.\n");

  1503. 

  1504.     ctx->frame_id++;

  1505. 

  1506.     /* get output buffer */

  1507.     frame->nb_samples = ctx->cur_frame_length;

  1508.     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) {

  1509.         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");

  1510.         return ret;

  1511.     }

  1512. 

  1513.     // transform decoded frame into output format

  1514.     #define INTERLEAVE_OUTPUT(bps)                                 \

  1515.     {                                                              \

  1516.         int##bps##_t *dest = (int##bps##_t*)frame->data[0];        \

  1517.         shift = bps - ctx->avctx->bits_per_raw_sample;             \

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

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

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

  1521.     }

  1522. 

  1523.     if (ctx->avctx->bits_per_raw_sample <= 16) {

  1524.         INTERLEAVE_OUTPUT(16)

  1525.     } else {

  1526.         INTERLEAVE_OUTPUT(32)

  1527.     }

  1528. 

  1529.     // update CRC

  1530.     if (sconf->crc_enabled && (avctx->err_recognition & AV_EF_CRCCHECK)) {

  1531.         int swap = HAVE_BIGENDIAN != sconf->msb_first;

  1532. 

  1533.         if (ctx->avctx->bits_per_raw_sample == 24) {

  1534.             int32_t *src = (int32_t *)frame->data[0];

  1535. 

  1536.             for (sample = 0;

  1537.                  sample < ctx->cur_frame_length * avctx->channels;

  1538.                  sample++) {

  1539.                 int32_t v;

  1540. 

  1541.                 if (swap)

  1542.                     v = av_bswap32(src[sample]);

  1543.                 else

  1544.                     v = src[sample];

  1545.                 if (!HAVE_BIGENDIAN)

  1546.                     v >>= 8;

  1547. 

  1548.                 ctx->crc = av_crc(ctx->crc_table, ctx->crc, (uint8_t*)(&v), 3);

  1549.             }

  1550.         } else {

  1551.             uint8_t *crc_source;

  1552. 

  1553.             if (swap) {

  1554.                 if (ctx->avctx->bits_per_raw_sample <= 16) {

  1555.                     int16_t *src  = (int16_t*) frame->data[0];

  1556.                     int16_t *dest = (int16_t*) ctx->crc_buffer;

  1557.                     for (sample = 0;

  1558.                          sample < ctx->cur_frame_length * avctx->channels;

  1559.                          sample++)

  1560.                         *dest++ = av_bswap16(src[sample]);

  1561.                 } else {

  1562.                     ctx->bdsp.bswap_buf((uint32_t *) ctx->crc_buffer,

  1563.                                         (uint32_t *) frame->data[0],

  1564.                                         ctx->cur_frame_length * avctx->channels);

  1565.                 }

  1566.                 crc_source = ctx->crc_buffer;

  1567.             } else {

  1568.                 crc_source = frame->data[0];

  1569.             }

  1570. 

  1571.             ctx->crc = av_crc(ctx->crc_table, ctx->crc, crc_source,

  1572.                               ctx->cur_frame_length * avctx->channels *

  1573.                               av_get_bytes_per_sample(avctx->sample_fmt));

  1574.         }

  1575. 

  1576. 

  1577.         // check CRC sums if this is the last frame

  1578.         if (ctx->cur_frame_length != sconf->frame_length &&

  1579.             ctx->crc_org != ctx->crc) {

  1580.             av_log(avctx, AV_LOG_ERROR, "CRC error.\n");

  1581.             if (avctx->err_recognition & AV_EF_EXPLODE)

  1582.                 return AVERROR_INVALIDDATA;

  1583.         }

  1584.     }

  1585. 

  1586.     *got_frame_ptr = 1;

  1587. 

  1588.     bytes_read = invalid_frame ? buffer_size :

  1589.                                  (bitstream_tell(&ctx->bc) + 7) >> 3;

  1590. 

  1591.     return bytes_read;

  1592. }

  1593. 

  1594. 

  1595. /** Uninitialize the ALS decoder.

  1596.  */

  1597. static av_cold int decode_end(AVCodecContext *avctx)

  1598. {

  1599.     ALSDecContext *ctx = avctx->priv_data;

  1600. 

  1601.     av_freep(&ctx->sconf.chan_pos);

  1602. 

  1603.     ff_bgmc_end(&ctx->bgmc_lut, &ctx->bgmc_lut_status);

  1604. 

  1605.     av_freep(&ctx->const_block);

  1606.     av_freep(&ctx->shift_lsbs);

  1607.     av_freep(&ctx->opt_order);

  1608.     av_freep(&ctx->store_prev_samples);

  1609.     av_freep(&ctx->use_ltp);

  1610.     av_freep(&ctx->ltp_lag);

  1611.     av_freep(&ctx->ltp_gain);

  1612.     av_freep(&ctx->ltp_gain_buffer);

  1613.     av_freep(&ctx->quant_cof);

  1614.     av_freep(&ctx->lpc_cof);

  1615.     av_freep(&ctx->quant_cof_buffer);

  1616.     av_freep(&ctx->lpc_cof_buffer);

  1617.     av_freep(&ctx->lpc_cof_reversed_buffer);

  1618.     av_freep(&ctx->prev_raw_samples);

  1619.     av_freep(&ctx->raw_samples);

  1620.     av_freep(&ctx->raw_buffer);

  1621.     av_freep(&ctx->chan_data);

  1622.     av_freep(&ctx->chan_data_buffer);

  1623.     av_freep(&ctx->reverted_channels);

  1624.     av_freep(&ctx->crc_buffer);

  1625. 

  1626.     return 0;

  1627. }

  1628. 

  1629. 

  1630. /** Initialize the ALS decoder.

  1631.  */

  1632. static av_cold int decode_init(AVCodecContext *avctx)

  1633. {

  1634.     unsigned int c;

  1635.     unsigned int channel_size;

  1636.     int num_buffers, ret;

  1637.     ALSDecContext *ctx = avctx->priv_data;

  1638.     ALSSpecificConfig *sconf = &ctx->sconf;

  1639.     ctx->avctx = avctx;

  1640. 

  1641.     if (!avctx->extradata) {

  1642.         av_log(avctx, AV_LOG_ERROR, "Missing required ALS extradata.\n");

  1643.         return AVERROR_INVALIDDATA;

  1644.     }

  1645. 

  1646.     if ((ret = read_specific_config(ctx)) < 0) {

  1647.         av_log(avctx, AV_LOG_ERROR, "Reading ALSSpecificConfig failed.\n");

  1648.         goto fail;

  1649.     }

  1650. 

  1651.     if ((ret = check_specific_config(ctx)) < 0) {

  1652.         goto fail;

  1653.     }

  1654. 

  1655.     if (sconf->bgmc) {

  1656.         ret = ff_bgmc_init(avctx, &ctx->bgmc_lut, &ctx->bgmc_lut_status);

  1657.         if (ret < 0)

  1658.             goto fail;

  1659.     }

  1660.     if (sconf->floating) {

  1661.         avctx->sample_fmt          = AV_SAMPLE_FMT_FLT;

  1662.         avctx->bits_per_raw_sample = 32;

  1663.     } else {

  1664.         avctx->sample_fmt          = sconf->resolution > 1

  1665.                                      ? AV_SAMPLE_FMT_S32 : AV_SAMPLE_FMT_S16;

  1666.         avctx->bits_per_raw_sample = (sconf->resolution + 1) * 8;

  1667.         if (avctx->bits_per_raw_sample > 32) {

  1668.             av_log(avctx, AV_LOG_ERROR, "Bits per raw sample %d larger than 32.\n",

  1669.                    avctx->bits_per_raw_sample);

  1670.             ret = AVERROR_INVALIDDATA;

  1671.             goto fail;

  1672.         }

  1673.     }

  1674. 

  1675.     // set maximum Rice parameter for progressive decoding based on resolution

  1676.     // This is not specified in 14496-3 but actually done by the reference

  1677.     // codec RM22 revision 2.

  1678.     ctx->s_max = sconf->resolution > 1 ? 31 : 15;

  1679. 

  1680.     // set lag value for long-term prediction

  1681.     ctx->ltp_lag_length = 8 + (avctx->sample_rate >=  96000) +

  1682.                               (avctx->sample_rate >= 192000);

  1683. 

  1684.     // allocate quantized parcor coefficient buffer

  1685.     num_buffers = sconf->mc_coding ? avctx->channels : 1;

  1686. 

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

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

  1689.     ctx->quant_cof_buffer = av_malloc(sizeof(*ctx->quant_cof_buffer) *

  1690.                                       num_buffers * sconf->max_order);

  1691.     ctx->lpc_cof_buffer   = av_malloc(sizeof(*ctx->lpc_cof_buffer) *

  1692.                                       num_buffers * sconf->max_order);

  1693.     ctx->lpc_cof_reversed_buffer = av_malloc(sizeof(*ctx->lpc_cof_buffer) *

  1694.                                              sconf->max_order);

  1695. 

  1696.     if (!ctx->quant_cof              || !ctx->lpc_cof        ||

  1697.         !ctx->quant_cof_buffer       || !ctx->lpc_cof_buffer ||

  1698.         !ctx->lpc_cof_reversed_buffer) {

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

  1700.         ret = AVERROR(ENOMEM);

  1701.         goto fail;

  1702.     }

  1703. 

  1704.     // assign quantized parcor coefficient buffers

  1705.     for (c = 0; c < num_buffers; c++) {

  1706.         ctx->quant_cof[c] = ctx->quant_cof_buffer + c * sconf->max_order;

  1707.         ctx->lpc_cof[c]   = ctx->lpc_cof_buffer   + c * sconf->max_order;

  1708.     }

  1709. 

  1710.     // allocate and assign lag and gain data buffer for ltp mode

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

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

  1713.     ctx->opt_order       = av_malloc (sizeof(*ctx->opt_order)   * num_buffers);

  1714.     ctx->store_prev_samples = av_malloc(sizeof(*ctx->store_prev_samples) * num_buffers);

  1715.     ctx->use_ltp         = av_mallocz(sizeof(*ctx->use_ltp)  * num_buffers);

  1716.     ctx->ltp_lag         = av_malloc (sizeof(*ctx->ltp_lag)  * num_buffers);

  1717.     ctx->ltp_gain        = av_malloc (sizeof(*ctx->ltp_gain) * num_buffers);

  1718.     ctx->ltp_gain_buffer = av_malloc (sizeof(*ctx->ltp_gain_buffer) *

  1719.                                       num_buffers * 5);

  1720. 

  1721.     if (!ctx->const_block || !ctx->shift_lsbs ||

  1722.         !ctx->opt_order || !ctx->store_prev_samples ||

  1723.         !ctx->use_ltp  || !ctx->ltp_lag ||

  1724.         !ctx->ltp_gain || !ctx->ltp_gain_buffer) {

  1725.         av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1726.         ret = AVERROR(ENOMEM);

  1727.         goto fail;

  1728.     }

  1729. 

  1730.     for (c = 0; c < num_buffers; c++)

  1731.         ctx->ltp_gain[c] = ctx->ltp_gain_buffer + c * 5;

  1732. 

  1733.     // allocate and assign channel data buffer for mcc mode

  1734.     if (sconf->mc_coding) {

  1735.         ctx->chan_data_buffer  = av_malloc(sizeof(*ctx->chan_data_buffer) *

  1736.                                            num_buffers * num_buffers);

  1737.         ctx->chan_data         = av_malloc(sizeof(*ctx->chan_data) *

  1738.                                            num_buffers);

  1739.         ctx->reverted_channels = av_malloc(sizeof(*ctx->reverted_channels) *

  1740.                                            num_buffers);

  1741. 

  1742.         if (!ctx->chan_data_buffer || !ctx->chan_data || !ctx->reverted_channels) {

  1743.             av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1744.             ret = AVERROR(ENOMEM);

  1745.             goto fail;

  1746.         }

  1747. 

  1748.         for (c = 0; c < num_buffers; c++)

  1749.             ctx->chan_data[c] = ctx->chan_data_buffer + c * num_buffers;

  1750.     } else {

  1751.         ctx->chan_data         = NULL;

  1752.         ctx->chan_data_buffer  = NULL;

  1753.         ctx->reverted_channels = NULL;

  1754.     }

  1755. 

  1756.     channel_size      = sconf->frame_length + sconf->max_order;

  1757. 

  1758.     ctx->prev_raw_samples = av_malloc (sizeof(*ctx->prev_raw_samples) * sconf->max_order);

  1759.     ctx->raw_buffer       = av_mallocz(sizeof(*ctx->     raw_buffer)  * avctx->channels * channel_size);

  1760.     ctx->raw_samples      = av_malloc (sizeof(*ctx->     raw_samples) * avctx->channels);

  1761. 

  1762.     // allocate previous raw sample buffer

  1763.     if (!ctx->prev_raw_samples || !ctx->raw_buffer|| !ctx->raw_samples) {

  1764.         av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1765.         ret = AVERROR(ENOMEM);

  1766.         goto fail;

  1767.     }

  1768. 

  1769.     // assign raw samples buffers

  1770.     ctx->raw_samples[0] = ctx->raw_buffer + sconf->max_order;

  1771.     for (c = 1; c < avctx->channels; c++)

  1772.         ctx->raw_samples[c] = ctx->raw_samples[c - 1] + channel_size;

  1773. 

  1774.     // allocate crc buffer

  1775.     if (HAVE_BIGENDIAN != sconf->msb_first && sconf->crc_enabled &&

  1776.         (avctx->err_recognition & AV_EF_CRCCHECK)) {

  1777.         ctx->crc_buffer = av_malloc(sizeof(*ctx->crc_buffer) *

  1778.                                     ctx->cur_frame_length *

  1779.                                     avctx->channels *

  1780.                                     av_get_bytes_per_sample(avctx->sample_fmt));

  1781.         if (!ctx->crc_buffer) {

  1782.             av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1783.             ret = AVERROR(ENOMEM);

  1784.             goto fail;

  1785.         }

  1786.     }

  1787. 

  1788.     ff_bswapdsp_init(&ctx->bdsp);

  1789. 

  1790.     return 0;

  1791. 

  1792. fail:

  1793.     decode_end(avctx);

  1794.     return ret;

  1795. }

  1796. 

  1797. 

  1798. /** Flush (reset) the frame ID after seeking.

  1799.  */

  1800. static av_cold void flush(AVCodecContext *avctx)

  1801. {

  1802.     ALSDecContext *ctx = avctx->priv_data;

  1803. 

  1804.     ctx->frame_id = 0;

  1805. }

  1806. 

  1807. 

  1808. AVCodec ff_als_decoder = {

  1809.     .name           = "als",

  1810.     .long_name      = NULL_IF_CONFIG_SMALL("MPEG-4 Audio Lossless Coding (ALS)"),

  1811.     .type           = AVMEDIA_TYPE_AUDIO,

  1812.     .id             = AV_CODEC_ID_MP4ALS,

  1813.     .priv_data_size = sizeof(ALSDecContext),

  1814.     .init           = decode_init,

  1815.     .close          = decode_end,

  1816.     .decode         = decode_frame,

  1817.     .flush          = flush,

  1818.     .capabilities   = AV_CODEC_CAP_SUBFRAMES | AV_CODEC_CAP_DR1,

  1819. };