/*
 * Copyright (c) 2016, Alliance for Open Media. All rights reserved
 *
 * This source code is subject to the terms of the BSD 2 Clause License and
 * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
 * was not distributed with this source code in the LICENSE file, you can
 * obtain it at www.aomedia.org/license/software. If the Alliance for Open
 * Media Patent License 1.0 was not distributed with this source code in the
 * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
 */

/*!\file
 * \brief Describes film grain parameters and film grain synthesis
 *
 */

#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include "aom_dsp/aom_dsp_common.h"
#include "aom_mem/aom_mem.h"
#include "av1/decoder/grain_synthesis.h"

// Samples with Gaussian distribution in the range of [-2048, 2047] (12 bits)
// with zero mean and standard deviation of about 512.
// should be divided by 4 for 10-bit range and 16 for 8-bit range.
static const int gaussian_sequence[2048] = {
  56,    568,   -180,  172,   124,   -84,   172,   -64,   -900,  24,   820,
  224,   1248,  996,   272,   -8,    -916,  -388,  -732,  -104,  -188, 800,
  112,   -652,  -320,  -376,  140,   -252,  492,   -168,  44,    -788, 588,
  -584,  500,   -228,  12,    680,   272,   -476,  972,   -100,  652,  368,
  432,   -196,  -720,  -192,  1000,  -332,  652,   -136,  -552,  -604, -4,
  192,   -220,  -136,  1000,  -52,   372,   -96,   -624,  124,   -24,  396,
  540,   -12,   -104,  640,   464,   244,   -208,  -84,   368,   -528, -740,
  248,   -968,  -848,  608,   376,   -60,   -292,  -40,   -156,  252,  -292,
  248,   224,   -280,  400,   -244,  244,   -60,   76,    -80,   212,  532,
  340,   128,   -36,   824,   -352,  -60,   -264,  -96,   -612,  416,  -704,
  220,   -204,  640,   -160,  1220,  -408,  900,   336,   20,    -336, -96,
  -792,  304,   48,    -28,   -1232, -1172, -448,  104,   -292,  -520, 244,
  60,    -948,  0,     -708,  268,   108,   356,   -548,  488,   -344, -136,
  488,   -196,  -224,  656,   -236,  -1128, 60,    4,     140,   276,  -676,
  -376,  168,   -108,  464,   8,     564,   64,    240,   308,   -300, -400,
  -456,  -136,  56,    120,   -408,  -116,  436,   504,   -232,  328,  844,
  -164,  -84,   784,   -168,  232,   -224,  348,   -376,  128,   568,  96,
  -1244, -288,  276,   848,   832,   -360,  656,   464,   -384,  -332, -356,
  728,   -388,  160,   -192,  468,   296,   224,   140,   -776,  -100, 280,
  4,     196,   44,    -36,   -648,  932,   16,    1428,  28,    528,  808,
  772,   20,    268,   88,    -332,  -284,  124,   -384,  -448,  208,  -228,
  -1044, -328,  660,   380,   -148,  -300,  588,   240,   540,   28,   136,
  -88,   -436,  256,   296,   -1000, 1400,  0,     -48,   1056,  -136, 264,
  -528,  -1108, 632,   -484,  -592,  -344,  796,   124,   -668,  -768, 388,
  1296,  -232,  -188,  -200,  -288,  -4,    308,   100,   -168,  256,  -500,
  204,   -508,  648,   -136,  372,   -272,  -120,  -1004, -552,  -548, -384,
  548,   -296,  428,   -108,  -8,    -912,  -324,  -224,  -88,   -112, -220,
  -100,  996,   -796,  548,   360,   -216,  180,   428,   -200,  -212, 148,
  96,    148,   284,   216,   -412,  -320,  120,   -300,  -384,  -604, -572,
  -332,  -8,    -180,  -176,  696,   116,   -88,   628,   76,    44,   -516,
  240,   -208,  -40,   100,   -592,  344,   -308,  -452,  -228,  20,   916,
  -1752, -136,  -340,  -804,  140,   40,    512,   340,   248,   184,  -492,
  896,   -156,  932,   -628,  328,   -688,  -448,  -616,  -752,  -100, 560,
  -1020, 180,   -800,  -64,   76,    576,   1068,  396,   660,   552,  -108,
  -28,   320,   -628,  312,   -92,   -92,   -472,  268,   16,    560,  516,
  -672,  -52,   492,   -100,  260,   384,   284,   292,   304,   -148, 88,
  -152,  1012,  1064,  -228,  164,   -376,  -684,  592,   -392,  156,  196,
  -524,  -64,   -884,  160,   -176,  636,   648,   404,   -396,  -436, 864,
  424,   -728,  988,   -604,  904,   -592,  296,   -224,  536,   -176, -920,
  436,   -48,   1176,  -884,  416,   -776,  -824,  -884,  524,   -548, -564,
  -68,   -164,  -96,   692,   364,   -692,  -1012, -68,   260,   -480, 876,
  -1116, 452,   -332,  -352,  892,   -1088, 1220,  -676,  12,    -292, 244,
  496,   372,   -32,   280,   200,   112,   -440,  -96,   24,    -644, -184,
  56,    -432,  224,   -980,  272,   -260,  144,   -436,  420,   356,  364,
  -528,  76,    172,   -744,  -368,  404,   -752,  -416,  684,   -688, 72,
  540,   416,   92,    444,   480,   -72,   -1416, 164,   -1172, -68,  24,
  424,   264,   1040,  128,   -912,  -524,  -356,  64,    876,   -12,  4,
  -88,   532,   272,   -524,  320,   276,   -508,  940,   24,    -400, -120,
  756,   60,    236,   -412,  100,   376,   -484,  400,   -100,  -740, -108,
  -260,  328,   -268,  224,   -200,  -416,  184,   -604,  -564,  -20,  296,
  60,    892,   -888,  60,    164,   68,    -760,  216,   -296,  904,  -336,
  -28,   404,   -356,  -568,  -208,  -1480, -512,  296,   328,   -360, -164,
  -1560, -776,  1156,  -428,  164,   -504,  -112,  120,   -216,  -148, -264,
  308,   32,    64,    -72,   72,    116,   176,   -64,   -272,  460,  -536,
  -784,  -280,  348,   108,   -752,  -132,  524,   -540,  -776,  116,  -296,
  -1196, -288,  -560,  1040,  -472,  116,   -848,  -1116, 116,   636,  696,
  284,   -176,  1016,  204,   -864,  -648,  -248,  356,   972,   -584, -204,
  264,   880,   528,   -24,   -184,  116,   448,   -144,  828,   524,  212,
  -212,  52,    12,    200,   268,   -488,  -404,  -880,  824,   -672, -40,
  908,   -248,  500,   716,   -576,  492,   -576,  16,    720,   -108, 384,
  124,   344,   280,   576,   -500,  252,   104,   -308,  196,   -188, -8,
  1268,  296,   1032,  -1196, 436,   316,   372,   -432,  -200,  -660, 704,
  -224,  596,   -132,  268,   32,    -452,  884,   104,   -1008, 424,  -1348,
  -280,  4,     -1168, 368,   476,   696,   300,   -8,    24,    180,  -592,
  -196,  388,   304,   500,   724,   -160,  244,   -84,   272,   -256, -420,
  320,   208,   -144,  -156,  156,   364,   452,   28,    540,   316,  220,
  -644,  -248,  464,   72,    360,   32,    -388,  496,   -680,  -48,  208,
  -116,  -408,  60,    -604,  -392,  548,   -840,  784,   -460,  656,  -544,
  -388,  -264,  908,   -800,  -628,  -612,  -568,  572,   -220,  164,  288,
  -16,   -308,  308,   -112,  -636,  -760,  280,   -668,  432,   364,  240,
  -196,  604,   340,   384,   196,   592,   -44,   -500,  432,   -580, -132,
  636,   -76,   392,   4,     -412,  540,   508,   328,   -356,  -36,  16,
  -220,  -64,   -248,  -60,   24,    -192,  368,   1040,  92,    -24,  -1044,
  -32,   40,    104,   148,   192,   -136,  -520,  56,    -816,  -224, 732,
  392,   356,   212,   -80,   -424,  -1008, -324,  588,   -1496, 576,  460,
  -816,  -848,  56,    -580,  -92,   -1372, -112,  -496,  200,   364,  52,
  -140,  48,    -48,   -60,   84,    72,    40,    132,   -356,  -268, -104,
  -284,  -404,  732,   -520,  164,   -304,  -540,  120,   328,   -76,  -460,
  756,   388,   588,   236,   -436,  -72,   -176,  -404,  -316,  -148, 716,
  -604,  404,   -72,   -88,   -888,  -68,   944,   88,    -220,  -344, 960,
  472,   460,   -232,  704,   120,   832,   -228,  692,   -508,  132,  -476,
  844,   -748,  -364,  -44,   1116,  -1104, -1056, 76,    428,   552,  -692,
  60,    356,   96,    -384,  -188,  -612,  -576,  736,   508,   892,  352,
  -1132, 504,   -24,   -352,  324,   332,   -600,  -312,  292,   508,  -144,
  -8,    484,   48,    284,   -260,  -240,  256,   -100,  -292,  -204, -44,
  472,   -204,  908,   -188,  -1000, -256,  92,    1164,  -392,  564,  356,
  652,   -28,   -884,  256,   484,   -192,  760,   -176,  376,   -524, -452,
  -436,  860,   -736,  212,   124,   504,   -476,  468,   76,    -472, 552,
  -692,  -944,  -620,  740,   -240,  400,   132,   20,    192,   -196, 264,
  -668,  -1012, -60,   296,   -316,  -828,  76,    -156,  284,   -768, -448,
  -832,  148,   248,   652,   616,   1236,  288,   -328,  -400,  -124, 588,
  220,   520,   -696,  1032,  768,   -740,  -92,   -272,  296,   448,  -464,
  412,   -200,  392,   440,   -200,  264,   -152,  -260,  320,   1032, 216,
  320,   -8,    -64,   156,   -1016, 1084,  1172,  536,   484,   -432, 132,
  372,   -52,   -256,  84,    116,   -352,  48,    116,   304,   -384, 412,
  924,   -300,  528,   628,   180,   648,   44,    -980,  -220,  1320, 48,
  332,   748,   524,   -268,  -720,  540,   -276,  564,   -344,  -208, -196,
  436,   896,   88,    -392,  132,   80,    -964,  -288,  568,   56,   -48,
  -456,  888,   8,     552,   -156,  -292,  948,   288,   128,   -716, -292,
  1192,  -152,  876,   352,   -600,  -260,  -812,  -468,  -28,   -120, -32,
  -44,   1284,  496,   192,   464,   312,   -76,   -516,  -380,  -456, -1012,
  -48,   308,   -156,  36,    492,   -156,  -808,  188,   1652,  68,   -120,
  -116,  316,   160,   -140,  352,   808,   -416,  592,   316,   -480, 56,
  528,   -204,  -568,  372,   -232,  752,   -344,  744,   -4,    324,  -416,
  -600,  768,   268,   -248,  -88,   -132,  -420,  -432,  80,    -288, 404,
  -316,  -1216, -588,  520,   -108,  92,    -320,  368,   -480,  -216, -92,
  1688,  -300,  180,   1020,  -176,  820,   -68,   -228,  -260,  436,  -904,
  20,    40,    -508,  440,   -736,  312,   332,   204,   760,   -372, 728,
  96,    -20,   -632,  -520,  -560,  336,   1076,  -64,   -532,  776,  584,
  192,   396,   -728,  -520,  276,   -188,  80,    -52,   -612,  -252, -48,
  648,   212,   -688,  228,   -52,   -260,  428,   -412,  -272,  -404, 180,
  816,   -796,  48,    152,   484,   -88,   -216,  988,   696,   188,  -528,
  648,   -116,  -180,  316,   476,   12,    -564,  96,    476,   -252, -364,
  -376,  -392,  556,   -256,  -576,  260,   -352,  120,   -16,   -136, -260,
  -492,  72,    556,   660,   580,   616,   772,   436,   424,   -32,  -324,
  -1268, 416,   -324,  -80,   920,   160,   228,   724,   32,    -516, 64,
  384,   68,    -128,  136,   240,   248,   -204,  -68,   252,   -932, -120,
  -480,  -628,  -84,   192,   852,   -404,  -288,  -132,  204,   100,  168,
  -68,   -196,  -868,  460,   1080,  380,   -80,   244,   0,     484,  -888,
  64,    184,   352,   600,   460,   164,   604,   -196,  320,   -64,  588,
  -184,  228,   12,    372,   48,    -848,  -344,  224,   208,   -200, 484,
  128,   -20,   272,   -468,  -840,  384,   256,   -720,  -520,  -464, -580,
  112,   -120,  644,   -356,  -208,  -608,  -528,  704,   560,   -424, 392,
  828,   40,    84,    200,   -152,  0,     -144,  584,   280,   -120, 80,
  -556,  -972,  -196,  -472,  724,   80,    168,   -32,   88,    160,  -688,
  0,     160,   356,   372,   -776,  740,   -128,  676,   -248,  -480, 4,
  -364,  96,    544,   232,   -1032, 956,   236,   356,   20,    -40,  300,
  24,    -676,  -596,  132,   1120,  -104,  532,   -1096, 568,   648,  444,
  508,   380,   188,   -376,  -604,  1488,  424,   24,    756,   -220, -192,
  716,   120,   920,   688,   168,   44,    -460,  568,   284,   1144, 1160,
  600,   424,   888,   656,   -356,  -320,  220,   316,   -176,  -724, -188,
  -816,  -628,  -348,  -228,  -380,  1012,  -452,  -660,  736,   928,  404,
  -696,  -72,   -268,  -892,  128,   184,   -344,  -780,  360,   336,  400,
  344,   428,   548,   -112,  136,   -228,  -216,  -820,  -516,  340,  92,
  -136,  116,   -300,  376,   -244,  100,   -316,  -520,  -284,  -12,  824,
  164,   -548,  -180,  -128,  116,   -924,  -828,  268,   -368,  -580, 620,
  192,   160,   0,     -1676, 1068,  424,   -56,   -360,  468,   -156, 720,
  288,   -528,  556,   -364,  548,   -148,  504,   316,   152,   -648, -620,
  -684,  -24,   -376,  -384,  -108,  -920,  -1032, 768,   180,   -264, -508,
  -1268, -260,  -60,   300,   -240,  988,   724,   -376,  -576,  -212, -736,
  556,   192,   1092,  -620,  -880,  376,   -56,   -4,    -216,  -32,  836,
  268,   396,   1332,  864,   -600,  100,   56,    -412,  -92,   356,  180,
  884,   -468,  -436,  292,   -388,  -804,  -704,  -840,  368,   -348, 140,
  -724,  1536,  940,   372,   112,   -372,  436,   -480,  1136,  296,  -32,
  -228,  132,   -48,   -220,  868,   -1016, -60,   -1044, -464,  328,  916,
  244,   12,    -736,  -296,  360,   468,   -376,  -108,  -92,   788,  368,
  -56,   544,   400,   -672,  -420,  728,   16,    320,   44,    -284, -380,
  -796,  488,   132,   204,   -596,  -372,  88,    -152,  -908,  -636, -572,
  -624,  -116,  -692,  -200,  -56,   276,   -88,   484,   -324,  948,  864,
  1000,  -456,  -184,  -276,  292,   -296,  156,   676,   320,   160,  908,
  -84,   -1236, -288,  -116,  260,   -372,  -644,  732,   -756,  -96,  84,
  344,   -520,  348,   -688,  240,   -84,   216,   -1044, -136,  -676, -396,
  -1500, 960,   -40,   176,   168,   1516,  420,   -504,  -344,  -364, -360,
  1216,  -940,  -380,  -212,  252,   -660,  -708,  484,   -444,  -152, 928,
  -120,  1112,  476,   -260,  560,   -148,  -344,  108,   -196,  228,  -288,
  504,   560,   -328,  -88,   288,   -1008, 460,   -228,  468,   -836, -196,
  76,    388,   232,   412,   -1168, -716,  -644,  756,   -172,  -356, -504,
  116,   432,   528,   48,    476,   -168,  -608,  448,   160,   -532, -272,
  28,    -676,  -12,   828,   980,   456,   520,   104,   -104,  256,  -344,
  -4,    -28,   -368,  -52,   -524,  -572,  -556,  -200,  768,   1124, -208,
  -512,  176,   232,   248,   -148,  -888,  604,   -600,  -304,  804,  -156,
  -212,  488,   -192,  -804,  -256,  368,   -360,  -916,  -328,  228,  -240,
  -448,  -472,  856,   -556,  -364,  572,   -12,   -156,  -368,  -340, 432,
  252,   -752,  -152,  288,   268,   -580,  -848,  -592,  108,   -76,  244,
  312,   -716,  592,   -80,   436,   360,   4,     -248,  160,   516,  584,
  732,   44,    -468,  -280,  -292,  -156,  -588,  28,    308,   912,  24,
  124,   156,   180,   -252,  944,   -924,  -772,  -520,  -428,  -624, 300,
  -212,  -1144, 32,    -724,  800,   -1128, -212,  -1288, -848,  180,  -416,
  440,   192,   -576,  -792,  -76,   -1080, 80,    -532,  -352,  -132, 380,
  -820,  148,   1112,  128,   164,   456,   700,   -924,  144,   -668, -384,
  648,   -832,  508,   552,   -52,   -100,  -656,  208,   -568,  748,  -88,
  680,   232,   300,   192,   -408,  -1012, -152,  -252,  -268,  272,  -876,
  -664,  -648,  -332,  -136,  16,    12,    1152,  -28,   332,   -536, 320,
  -672,  -460,  -316,  532,   -260,  228,   -40,   1052,  -816,  180,  88,
  -496,  -556,  -672,  -368,  428,   92,    356,   404,   -408,  252,  196,
  -176,  -556,  792,   268,   32,    372,   40,    96,    -332,  328,  120,
  372,   -900,  -40,   472,   -264,  -592,  952,   128,   656,   112,  664,
  -232,  420,   4,     -344,  -464,  556,   244,   -416,  -32,   252,  0,
  -412,  188,   -696,  508,   -476,  324,   -1096, 656,   -312,  560,  264,
  -136,  304,   160,   -64,   -580,  248,   336,   -720,  560,   -348, -288,
  -276,  -196,  -500,  852,   -544,  -236,  -1128, -992,  -776,  116,  56,
  52,    860,   884,   212,   -12,   168,   1020,  512,   -552,  924,  -148,
  716,   188,   164,   -340,  -520,  -184,  880,   -152,  -680,  -208, -1156,
  -300,  -528,  -472,  364,   100,   -744,  -1056, -32,   540,   280,  144,
  -676,  -32,   -232,  -280,  -224,  96,    568,   -76,   172,   148,  148,
  104,   32,    -296,  -32,   788,   -80,   32,    -16,   280,   288,  944,
  428,   -484
};

static const int gauss_bits = 11;

static int luma_subblock_size_y = 32;
static int luma_subblock_size_x = 32;

static int chroma_subblock_size_y = 16;
static int chroma_subblock_size_x = 16;

static const int min_luma_legal_range = 16;
static const int max_luma_legal_range = 235;

static const int min_chroma_legal_range = 16;
static const int max_chroma_legal_range = 240;

static int scaling_lut_y[256];
static int scaling_lut_cb[256];
static int scaling_lut_cr[256];

static int grain_min;
static int grain_max;

static uint16_t random_register = 0;  // random number generator register

static void dealloc_arrays(const aom_film_grain_t *params, int ***pred_pos_luma,
                           int ***pred_pos_chroma, int **luma_grain_block,
                           int **cb_grain_block, int **cr_grain_block,
                           int **y_line_buf, int **cb_line_buf,
                           int **cr_line_buf, int **y_col_buf, int **cb_col_buf,
                           int **cr_col_buf) {
  int num_pos_luma = 2 * params->ar_coeff_lag * (params->ar_coeff_lag + 1);
  int num_pos_chroma = num_pos_luma;
  if (params->num_y_points > 0) ++num_pos_chroma;

  if (*pred_pos_luma) {
    for (int row = 0; row < num_pos_luma; row++) {
      aom_free((*pred_pos_luma)[row]);
    }
    aom_free(*pred_pos_luma);
    *pred_pos_luma = NULL;
  }

  if (*pred_pos_chroma) {
    for (int row = 0; row < num_pos_chroma; row++) {
      aom_free((*pred_pos_chroma)[row]);
    }
    aom_free(*pred_pos_chroma);
    *pred_pos_chroma = NULL;
  }

  aom_free(*y_line_buf);
  *y_line_buf = NULL;

  aom_free(*cb_line_buf);
  *cb_line_buf = NULL;

  aom_free(*cr_line_buf);
  *cr_line_buf = NULL;

  aom_free(*y_col_buf);
  *y_col_buf = NULL;

  aom_free(*cb_col_buf);
  *cb_col_buf = NULL;

  aom_free(*cr_col_buf);
  *cr_col_buf = NULL;

  aom_free(*luma_grain_block);
  *luma_grain_block = NULL;

  aom_free(*cb_grain_block);
  *cb_grain_block = NULL;

  aom_free(*cr_grain_block);
  *cr_grain_block = NULL;
}

static bool init_arrays(const aom_film_grain_t *params, int luma_stride,
                        int chroma_stride, int ***pred_pos_luma_p,
                        int ***pred_pos_chroma_p, int **luma_grain_block,
                        int **cb_grain_block, int **cr_grain_block,
                        int **y_line_buf, int **cb_line_buf, int **cr_line_buf,
                        int **y_col_buf, int **cb_col_buf, int **cr_col_buf,
                        int luma_grain_samples, int chroma_grain_samples,
                        int chroma_subsamp_y, int chroma_subsamp_x) {
  *pred_pos_luma_p = NULL;
  *pred_pos_chroma_p = NULL;
  *luma_grain_block = NULL;
  *cb_grain_block = NULL;
  *cr_grain_block = NULL;
  *y_line_buf = NULL;
  *cb_line_buf = NULL;
  *cr_line_buf = NULL;
  *y_col_buf = NULL;
  *cb_col_buf = NULL;
  *cr_col_buf = NULL;

  memset(scaling_lut_y, 0, sizeof(*scaling_lut_y) * 256);
  memset(scaling_lut_cb, 0, sizeof(*scaling_lut_cb) * 256);
  memset(scaling_lut_cr, 0, sizeof(*scaling_lut_cr) * 256);

  int num_pos_luma = 2 * params->ar_coeff_lag * (params->ar_coeff_lag + 1);
  int num_pos_chroma = num_pos_luma;
  if (params->num_y_points > 0) ++num_pos_chroma;

  int **pred_pos_luma;
  int **pred_pos_chroma;

  pred_pos_luma = (int **)aom_calloc(num_pos_luma, sizeof(*pred_pos_luma));
  if (!pred_pos_luma) return false;

  for (int row = 0; row < num_pos_luma; row++) {
    pred_pos_luma[row] = (int *)aom_malloc(sizeof(**pred_pos_luma) * 3);
    if (!pred_pos_luma[row]) {
      dealloc_arrays(params, pred_pos_luma_p, pred_pos_chroma_p,
                     luma_grain_block, cb_grain_block, cr_grain_block,
                     y_line_buf, cb_line_buf, cr_line_buf, y_col_buf,
                     cb_col_buf, cr_col_buf);
      return false;
    }
  }

  pred_pos_chroma =
      (int **)aom_calloc(num_pos_chroma, sizeof(*pred_pos_chroma));
  if (!pred_pos_chroma) {
    dealloc_arrays(params, pred_pos_luma_p, pred_pos_chroma_p, luma_grain_block,
                   cb_grain_block, cr_grain_block, y_line_buf, cb_line_buf,
                   cr_line_buf, y_col_buf, cb_col_buf, cr_col_buf);
    return false;
  }

  for (int row = 0; row < num_pos_chroma; row++) {
    pred_pos_chroma[row] = (int *)aom_malloc(sizeof(**pred_pos_chroma) * 3);
    if (!pred_pos_chroma[row]) {
      dealloc_arrays(params, pred_pos_luma_p, pred_pos_chroma_p,
                     luma_grain_block, cb_grain_block, cr_grain_block,
                     y_line_buf, cb_line_buf, cr_line_buf, y_col_buf,
                     cb_col_buf, cr_col_buf);
      return false;
    }
  }

  int pos_ar_index = 0;

  for (int row = -params->ar_coeff_lag; row < 0; row++) {
    for (int col = -params->ar_coeff_lag; col < params->ar_coeff_lag + 1;
         col++) {
      pred_pos_luma[pos_ar_index][0] = row;
      pred_pos_luma[pos_ar_index][1] = col;
      pred_pos_luma[pos_ar_index][2] = 0;

      pred_pos_chroma[pos_ar_index][0] = row;
      pred_pos_chroma[pos_ar_index][1] = col;
      pred_pos_chroma[pos_ar_index][2] = 0;
      ++pos_ar_index;
    }
  }

  for (int col = -params->ar_coeff_lag; col < 0; col++) {
    pred_pos_luma[pos_ar_index][0] = 0;
    pred_pos_luma[pos_ar_index][1] = col;
    pred_pos_luma[pos_ar_index][2] = 0;

    pred_pos_chroma[pos_ar_index][0] = 0;
    pred_pos_chroma[pos_ar_index][1] = col;
    pred_pos_chroma[pos_ar_index][2] = 0;

    ++pos_ar_index;
  }

  if (params->num_y_points > 0) {
    pred_pos_chroma[pos_ar_index][0] = 0;
    pred_pos_chroma[pos_ar_index][1] = 0;
    pred_pos_chroma[pos_ar_index][2] = 1;
  }

  *pred_pos_luma_p = pred_pos_luma;
  *pred_pos_chroma_p = pred_pos_chroma;

  *y_line_buf = (int *)aom_malloc(sizeof(**y_line_buf) * luma_stride * 2);
  *cb_line_buf = (int *)aom_malloc(sizeof(**cb_line_buf) * chroma_stride *
                                   (2 >> chroma_subsamp_y));
  *cr_line_buf = (int *)aom_malloc(sizeof(**cr_line_buf) * chroma_stride *
                                   (2 >> chroma_subsamp_y));

  *y_col_buf =
      (int *)aom_malloc(sizeof(**y_col_buf) * (luma_subblock_size_y + 2) * 2);
  *cb_col_buf =
      (int *)aom_malloc(sizeof(**cb_col_buf) *
                        (chroma_subblock_size_y + (2 >> chroma_subsamp_y)) *
                        (2 >> chroma_subsamp_x));
  *cr_col_buf =
      (int *)aom_malloc(sizeof(**cr_col_buf) *
                        (chroma_subblock_size_y + (2 >> chroma_subsamp_y)) *
                        (2 >> chroma_subsamp_x));

  *luma_grain_block =
      (int *)aom_malloc(sizeof(**luma_grain_block) * luma_grain_samples);
  *cb_grain_block =
      (int *)aom_malloc(sizeof(**cb_grain_block) * chroma_grain_samples);
  *cr_grain_block =
      (int *)aom_malloc(sizeof(**cr_grain_block) * chroma_grain_samples);
  if (!(*pred_pos_luma_p && *pred_pos_chroma_p && *y_line_buf && *cb_line_buf &&
        *cr_line_buf && *y_col_buf && *cb_col_buf && *cr_col_buf &&
        *luma_grain_block && *cb_grain_block && *cr_grain_block)) {
    dealloc_arrays(params, pred_pos_luma_p, pred_pos_chroma_p, luma_grain_block,
                   cb_grain_block, cr_grain_block, y_line_buf, cb_line_buf,
                   cr_line_buf, y_col_buf, cb_col_buf, cr_col_buf);
    return false;
  }
  return true;
}

// get a number between 0 and 2^bits - 1
static INLINE int get_random_number(int bits) {
  uint16_t bit;
  bit = ((random_register >> 0) ^ (random_register >> 1) ^
         (random_register >> 3) ^ (random_register >> 12)) &
        1;
  random_register = (random_register >> 1) | (bit << 15);
  return (random_register >> (16 - bits)) & ((1 << bits) - 1);
}

static void init_random_generator(int luma_line, uint16_t seed) {
  // same for the picture

  uint16_t msb = (seed >> 8) & 255;
  uint16_t lsb = seed & 255;

  random_register = (msb << 8) + lsb;

  //  changes for each row
  int luma_num = luma_line >> 5;

  random_register ^= ((luma_num * 37 + 178) & 255) << 8;
  random_register ^= ((luma_num * 173 + 105) & 255);
}

static void generate_luma_grain_block(
    const aom_film_grain_t *params, int **pred_pos_luma, int *luma_grain_block,
    int luma_block_size_y, int luma_block_size_x, int luma_grain_stride,
    int left_pad, int top_pad, int right_pad, int bottom_pad) {
  if (params->num_y_points == 0) {
    memset(luma_grain_block, 0,
           sizeof(*luma_grain_block) * luma_block_size_y * luma_grain_stride);
    return;
  }

  int bit_depth = params->bit_depth;
  int gauss_sec_shift = 12 - bit_depth + params->grain_scale_shift;

  int num_pos_luma = 2 * params->ar_coeff_lag * (params->ar_coeff_lag + 1);
  int rounding_offset = (1 << (params->ar_coeff_shift - 1));

  for (int i = 0; i < luma_block_size_y; i++)
    for (int j = 0; j < luma_block_size_x; j++)
      luma_grain_block[i * luma_grain_stride + j] =
          (gaussian_sequence[get_random_number(gauss_bits)] +
           ((1 << gauss_sec_shift) >> 1)) >>
          gauss_sec_shift;

  for (int i = top_pad; i < luma_block_size_y - bottom_pad; i++)
    for (int j = left_pad; j < luma_block_size_x - right_pad; j++) {
      int wsum = 0;
      for (int pos = 0; pos < num_pos_luma; pos++) {
        wsum = wsum + params->ar_coeffs_y[pos] *
                          luma_grain_block[(i + pred_pos_luma[pos][0]) *
                                               luma_grain_stride +
                                           j + pred_pos_luma[pos][1]];
      }
      luma_grain_block[i * luma_grain_stride + j] =
          clamp(luma_grain_block[i * luma_grain_stride + j] +
                    ((wsum + rounding_offset) >> params->ar_coeff_shift),
                grain_min, grain_max);
    }
}

static bool generate_chroma_grain_blocks(
    const aom_film_grain_t *params, int **pred_pos_chroma,
    int *luma_grain_block, int *cb_grain_block, int *cr_grain_block,
    int luma_grain_stride, int chroma_block_size_y, int chroma_block_size_x,
    int chroma_grain_stride, int left_pad, int top_pad, int right_pad,
    int bottom_pad, int chroma_subsamp_y, int chroma_subsamp_x) {
  int bit_depth = params->bit_depth;
  int gauss_sec_shift = 12 - bit_depth + params->grain_scale_shift;

  int num_pos_chroma = 2 * params->ar_coeff_lag * (params->ar_coeff_lag + 1);
  if (params->num_y_points > 0) ++num_pos_chroma;
  int rounding_offset = (1 << (params->ar_coeff_shift - 1));
  int chroma_grain_block_size = chroma_block_size_y * chroma_grain_stride;

  if (params->num_cb_points || params->chroma_scaling_from_luma) {
    init_random_generator(7 << 5, params->random_seed);

    for (int i = 0; i < chroma_block_size_y; i++)
      for (int j = 0; j < chroma_block_size_x; j++)
        cb_grain_block[i * chroma_grain_stride + j] =
            (gaussian_sequence[get_random_number(gauss_bits)] +
             ((1 << gauss_sec_shift) >> 1)) >>
            gauss_sec_shift;
  } else {
    memset(cb_grain_block, 0,
           sizeof(*cb_grain_block) * chroma_grain_block_size);
  }

  if (params->num_cr_points || params->chroma_scaling_from_luma) {
    init_random_generator(11 << 5, params->random_seed);

    for (int i = 0; i < chroma_block_size_y; i++)
      for (int j = 0; j < chroma_block_size_x; j++)
        cr_grain_block[i * chroma_grain_stride + j] =
            (gaussian_sequence[get_random_number(gauss_bits)] +
             ((1 << gauss_sec_shift) >> 1)) >>
            gauss_sec_shift;
  } else {
    memset(cr_grain_block, 0,
           sizeof(*cr_grain_block) * chroma_grain_block_size);
  }

  for (int i = top_pad; i < chroma_block_size_y - bottom_pad; i++)
    for (int j = left_pad; j < chroma_block_size_x - right_pad; j++) {
      int wsum_cb = 0;
      int wsum_cr = 0;
      for (int pos = 0; pos < num_pos_chroma; pos++) {
        if (pred_pos_chroma[pos][2] == 0) {
          wsum_cb = wsum_cb + params->ar_coeffs_cb[pos] *
                                  cb_grain_block[(i + pred_pos_chroma[pos][0]) *
                                                     chroma_grain_stride +
                                                 j + pred_pos_chroma[pos][1]];
          wsum_cr = wsum_cr + params->ar_coeffs_cr[pos] *
                                  cr_grain_block[(i + pred_pos_chroma[pos][0]) *
                                                     chroma_grain_stride +
                                                 j + pred_pos_chroma[pos][1]];
        } else if (pred_pos_chroma[pos][2] == 1) {
          int av_luma = 0;
          int luma_coord_y = ((i - top_pad) << chroma_subsamp_y) + top_pad;
          int luma_coord_x = ((j - left_pad) << chroma_subsamp_x) + left_pad;

          for (int k = luma_coord_y; k < luma_coord_y + chroma_subsamp_y + 1;
               k++)
            for (int l = luma_coord_x; l < luma_coord_x + chroma_subsamp_x + 1;
                 l++)
              av_luma += luma_grain_block[k * luma_grain_stride + l];

          av_luma =
              (av_luma + ((1 << (chroma_subsamp_y + chroma_subsamp_x)) >> 1)) >>
              (chroma_subsamp_y + chroma_subsamp_x);

          wsum_cb = wsum_cb + params->ar_coeffs_cb[pos] * av_luma;
          wsum_cr = wsum_cr + params->ar_coeffs_cr[pos] * av_luma;
        } else {
          fprintf(
              stderr,
              "Grain synthesis: prediction between two chroma components is "
              "not supported!");
          return false;
        }
      }
      if (params->num_cb_points || params->chroma_scaling_from_luma)
        cb_grain_block[i * chroma_grain_stride + j] =
            clamp(cb_grain_block[i * chroma_grain_stride + j] +
                      ((wsum_cb + rounding_offset) >> params->ar_coeff_shift),
                  grain_min, grain_max);
      if (params->num_cr_points || params->chroma_scaling_from_luma)
        cr_grain_block[i * chroma_grain_stride + j] =
            clamp(cr_grain_block[i * chroma_grain_stride + j] +
                      ((wsum_cr + rounding_offset) >> params->ar_coeff_shift),
                  grain_min, grain_max);
    }
  return true;
}

static void init_scaling_function(const int scaling_points[][2], int num_points,
                                  int scaling_lut[]) {
  if (num_points == 0) return;

  for (int i = 0; i < scaling_points[0][0]; i++)
    scaling_lut[i] = scaling_points[0][1];

  for (int point = 0; point < num_points - 1; point++) {
    int delta_y = scaling_points[point + 1][1] - scaling_points[point][1];
    int delta_x = scaling_points[point + 1][0] - scaling_points[point][0];

    int64_t delta = delta_y * ((65536 + (delta_x >> 1)) / delta_x);

    for (int x = 0; x < delta_x; x++) {
      scaling_lut[scaling_points[point][0] + x] =
          scaling_points[point][1] + (int)((x * delta + 32768) >> 16);
    }
  }

  for (int i = scaling_points[num_points - 1][0]; i < 256; i++)
    scaling_lut[i] = scaling_points[num_points - 1][1];
}

// function that extracts samples from a LUT (and interpolates intemediate
// frames for 10- and 12-bit video)
static int scale_LUT(int *scaling_lut, int index, int bit_depth) {
  int x = index >> (bit_depth - 8);

  if (!(bit_depth - 8) || x == 255)
    return scaling_lut[x];
  else
    return scaling_lut[x] + (((scaling_lut[x + 1] - scaling_lut[x]) *
                                  (index & ((1 << (bit_depth - 8)) - 1)) +
                              (1 << (bit_depth - 9))) >>
                             (bit_depth - 8));
}

static void add_noise_to_block(const aom_film_grain_t *params, uint8_t *luma,
                               uint8_t *cb, uint8_t *cr, int luma_stride,
                               int chroma_stride, int *luma_grain,
                               int *cb_grain, int *cr_grain,
                               int luma_grain_stride, int chroma_grain_stride,
                               int half_luma_height, int half_luma_width,
                               int bit_depth, int chroma_subsamp_y,
                               int chroma_subsamp_x, int mc_identity) {
  int cb_mult = params->cb_mult - 128;            // fixed scale
  int cb_luma_mult = params->cb_luma_mult - 128;  // fixed scale
  int cb_offset = params->cb_offset - 256;

  int cr_mult = params->cr_mult - 128;            // fixed scale
  int cr_luma_mult = params->cr_luma_mult - 128;  // fixed scale
  int cr_offset = params->cr_offset - 256;

  int rounding_offset = (1 << (params->scaling_shift - 1));

  int apply_y = params->num_y_points > 0 ? 1 : 0;
  int apply_cb =
      (params->num_cb_points > 0 || params->chroma_scaling_from_luma) ? 1 : 0;
  int apply_cr =
      (params->num_cr_points > 0 || params->chroma_scaling_from_luma) ? 1 : 0;

  if (params->chroma_scaling_from_luma) {
    cb_mult = 0;        // fixed scale
    cb_luma_mult = 64;  // fixed scale
    cb_offset = 0;

    cr_mult = 0;        // fixed scale
    cr_luma_mult = 64;  // fixed scale
    cr_offset = 0;
  }

  int min_luma, max_luma, min_chroma, max_chroma;

  if (params->clip_to_restricted_range) {
    min_luma = min_luma_legal_range;
    max_luma = max_luma_legal_range;

    if (mc_identity) {
      min_chroma = min_luma_legal_range;
      max_chroma = max_luma_legal_range;
    } else {
      min_chroma = min_chroma_legal_range;
      max_chroma = max_chroma_legal_range;
    }
  } else {
    min_luma = min_chroma = 0;
    max_luma = max_chroma = 255;
  }

  for (int i = 0; i < (half_luma_height << (1 - chroma_subsamp_y)); i++) {
    for (int j = 0; j < (half_luma_width << (1 - chroma_subsamp_x)); j++) {
      int average_luma = 0;
      if (chroma_subsamp_x) {
        average_luma = (luma[(i << chroma_subsamp_y) * luma_stride +
                             (j << chroma_subsamp_x)] +
                        luma[(i << chroma_subsamp_y) * luma_stride +
                             (j << chroma_subsamp_x) + 1] +
                        1) >>
                       1;
      } else {
        average_luma = luma[(i << chroma_subsamp_y) * luma_stride + j];
      }

      if (apply_cb) {
        cb[i * chroma_stride + j] = clamp(
            cb[i * chroma_stride + j] +
                ((scale_LUT(scaling_lut_cb,
                            clamp(((average_luma * cb_luma_mult +
                                    cb_mult * cb[i * chroma_stride + j]) >>
                                   6) +
                                      cb_offset,
                                  0, (256 << (bit_depth - 8)) - 1),
                            8) *
                      cb_grain[i * chroma_grain_stride + j] +
                  rounding_offset) >>
                 params->scaling_shift),
            min_chroma, max_chroma);
      }

      if (apply_cr) {
        cr[i * chroma_stride + j] = clamp(
            cr[i * chroma_stride + j] +
                ((scale_LUT(scaling_lut_cr,
                            clamp(((average_luma * cr_luma_mult +
                                    cr_mult * cr[i * chroma_stride + j]) >>
                                   6) +
                                      cr_offset,
                                  0, (256 << (bit_depth - 8)) - 1),
                            8) *
                      cr_grain[i * chroma_grain_stride + j] +
                  rounding_offset) >>
                 params->scaling_shift),
            min_chroma, max_chroma);
      }
    }
  }

  if (apply_y) {
    for (int i = 0; i < (half_luma_height << 1); i++) {
      for (int j = 0; j < (half_luma_width << 1); j++) {
        luma[i * luma_stride + j] =
            clamp(luma[i * luma_stride + j] +
                      ((scale_LUT(scaling_lut_y, luma[i * luma_stride + j], 8) *
                            luma_grain[i * luma_grain_stride + j] +
                        rounding_offset) >>
                       params->scaling_shift),
                  min_luma, max_luma);
      }
    }
  }
}

static void add_noise_to_block_hbd(
    const aom_film_grain_t *params, uint16_t *luma, uint16_t *cb, uint16_t *cr,
    int luma_stride, int chroma_stride, int *luma_grain, int *cb_grain,
    int *cr_grain, int luma_grain_stride, int chroma_grain_stride,
    int half_luma_height, int half_luma_width, int bit_depth,
    int chroma_subsamp_y, int chroma_subsamp_x, int mc_identity) {
  int cb_mult = params->cb_mult - 128;            // fixed scale
  int cb_luma_mult = params->cb_luma_mult - 128;  // fixed scale
  // offset value depends on the bit depth
  int cb_offset = (params->cb_offset << (bit_depth - 8)) - (1 << bit_depth);

  int cr_mult = params->cr_mult - 128;            // fixed scale
  int cr_luma_mult = params->cr_luma_mult - 128;  // fixed scale
  // offset value depends on the bit depth
  int cr_offset = (params->cr_offset << (bit_depth - 8)) - (1 << bit_depth);

  int rounding_offset = (1 << (params->scaling_shift - 1));

  int apply_y = params->num_y_points > 0 ? 1 : 0;
  int apply_cb =
      (params->num_cb_points > 0 || params->chroma_scaling_from_luma) > 0 ? 1
                                                                          : 0;
  int apply_cr =
      (params->num_cr_points > 0 || params->chroma_scaling_from_luma) > 0 ? 1
                                                                          : 0;

  if (params->chroma_scaling_from_luma) {
    cb_mult = 0;        // fixed scale
    cb_luma_mult = 64;  // fixed scale
    cb_offset = 0;

    cr_mult = 0;        // fixed scale
    cr_luma_mult = 64;  // fixed scale
    cr_offset = 0;
  }

  int min_luma, max_luma, min_chroma, max_chroma;

  if (params->clip_to_restricted_range) {
    min_luma = min_luma_legal_range << (bit_depth - 8);
    max_luma = max_luma_legal_range << (bit_depth - 8);

    if (mc_identity) {
      min_chroma = min_luma_legal_range << (bit_depth - 8);
      max_chroma = max_luma_legal_range << (bit_depth - 8);
    } else {
      min_chroma = min_chroma_legal_range << (bit_depth - 8);
      max_chroma = max_chroma_legal_range << (bit_depth - 8);
    }
  } else {
    min_luma = min_chroma = 0;
    max_luma = max_chroma = (256 << (bit_depth - 8)) - 1;
  }

  for (int i = 0; i < (half_luma_height << (1 - chroma_subsamp_y)); i++) {
    for (int j = 0; j < (half_luma_width << (1 - chroma_subsamp_x)); j++) {
      int average_luma = 0;
      if (chroma_subsamp_x) {
        average_luma = (luma[(i << chroma_subsamp_y) * luma_stride +
                             (j << chroma_subsamp_x)] +
                        luma[(i << chroma_subsamp_y) * luma_stride +
                             (j << chroma_subsamp_x) + 1] +
                        1) >>
                       1;
      } else {
        average_luma = luma[(i << chroma_subsamp_y) * luma_stride + j];
      }

      if (apply_cb) {
        cb[i * chroma_stride + j] = clamp(
            cb[i * chroma_stride + j] +
                ((scale_LUT(scaling_lut_cb,
                            clamp(((average_luma * cb_luma_mult +
                                    cb_mult * cb[i * chroma_stride + j]) >>
                                   6) +
                                      cb_offset,
                                  0, (256 << (bit_depth - 8)) - 1),
                            bit_depth) *
                      cb_grain[i * chroma_grain_stride + j] +
                  rounding_offset) >>
                 params->scaling_shift),
            min_chroma, max_chroma);
      }
      if (apply_cr) {
        cr[i * chroma_stride + j] = clamp(
            cr[i * chroma_stride + j] +
                ((scale_LUT(scaling_lut_cr,
                            clamp(((average_luma * cr_luma_mult +
                                    cr_mult * cr[i * chroma_stride + j]) >>
                                   6) +
                                      cr_offset,
                                  0, (256 << (bit_depth - 8)) - 1),
                            bit_depth) *
                      cr_grain[i * chroma_grain_stride + j] +
                  rounding_offset) >>
                 params->scaling_shift),
            min_chroma, max_chroma);
      }
    }
  }

  if (apply_y) {
    for (int i = 0; i < (half_luma_height << 1); i++) {
      for (int j = 0; j < (half_luma_width << 1); j++) {
        luma[i * luma_stride + j] =
            clamp(luma[i * luma_stride + j] +
                      ((scale_LUT(scaling_lut_y, luma[i * luma_stride + j],
                                  bit_depth) *
                            luma_grain[i * luma_grain_stride + j] +
                        rounding_offset) >>
                       params->scaling_shift),
                  min_luma, max_luma);
      }
    }
  }
}

static void copy_rect(uint8_t *src, int src_stride, uint8_t *dst,
                      int dst_stride, int width, int height,
                      int use_high_bit_depth) {
  int hbd_coeff = use_high_bit_depth ? 2 : 1;
  while (height) {
    memcpy(dst, src, width * sizeof(uint8_t) * hbd_coeff);
    src += src_stride;
    dst += dst_stride;
    --height;
  }
  return;
}

static void copy_area(int *src, int src_stride, int *dst, int dst_stride,
                      int width, int height) {
  while (height) {
    memcpy(dst, src, width * sizeof(*src));
    src += src_stride;
    dst += dst_stride;
    --height;
  }
  return;
}

static void extend_even(uint8_t *dst, int dst_stride, int width, int height,
                        int use_high_bit_depth) {
  if ((width & 1) == 0 && (height & 1) == 0) return;
  if (use_high_bit_depth) {
    uint16_t *dst16 = (uint16_t *)dst;
    int dst16_stride = dst_stride / 2;
    if (width & 1) {
      for (int i = 0; i < height; ++i)
        dst16[i * dst16_stride + width] = dst16[i * dst16_stride + width - 1];
    }
    width = (width + 1) & (~1);
    if (height & 1) {
      memcpy(&dst16[height * dst16_stride], &dst16[(height - 1) * dst16_stride],
             sizeof(*dst16) * width);
    }
  } else {
    if (width & 1) {
      for (int i = 0; i < height; ++i)
        dst[i * dst_stride + width] = dst[i * dst_stride + width - 1];
    }
    width = (width + 1) & (~1);
    if (height & 1) {
      memcpy(&dst[height * dst_stride], &dst[(height - 1) * dst_stride],
             sizeof(*dst) * width);
    }
  }
}

static void ver_boundary_overlap(int *left_block, int left_stride,
                                 int *right_block, int right_stride,
                                 int *dst_block, int dst_stride, int width,
                                 int height) {
  if (width == 1) {
    while (height) {
      *dst_block = clamp((*left_block * 23 + *right_block * 22 + 16) >> 5,
                         grain_min, grain_max);
      left_block += left_stride;
      right_block += right_stride;
      dst_block += dst_stride;
      --height;
    }
    return;
  } else if (width == 2) {
    while (height) {
      dst_block[0] = clamp((27 * left_block[0] + 17 * right_block[0] + 16) >> 5,
                           grain_min, grain_max);
      dst_block[1] = clamp((17 * left_block[1] + 27 * right_block[1] + 16) >> 5,
                           grain_min, grain_max);
      left_block += left_stride;
      right_block += right_stride;
      dst_block += dst_stride;
      --height;
    }
    return;
  }
}

static void hor_boundary_overlap(int *top_block, int top_stride,
                                 int *bottom_block, int bottom_stride,
                                 int *dst_block, int dst_stride, int width,
                                 int height) {
  if (height == 1) {
    while (width) {
      *dst_block = clamp((*top_block * 23 + *bottom_block * 22 + 16) >> 5,
                         grain_min, grain_max);
      ++top_block;
      ++bottom_block;
      ++dst_block;
      --width;
    }
    return;
  } else if (height == 2) {
    while (width) {
      dst_block[0] = clamp((27 * top_block[0] + 17 * bottom_block[0] + 16) >> 5,
                           grain_min, grain_max);
      dst_block[dst_stride] = clamp((17 * top_block[top_stride] +
                                     27 * bottom_block[bottom_stride] + 16) >>
                                        5,
                                    grain_min, grain_max);
      ++top_block;
      ++bottom_block;
      ++dst_block;
      --width;
    }
    return;
  }
}

int av1_add_film_grain(const aom_film_grain_t *params, const aom_image_t *src,
                       aom_image_t *dst) {
  uint8_t *luma, *cb, *cr;
  int height, width, luma_stride, chroma_stride;
  int use_high_bit_depth = 0;
  int chroma_subsamp_x = 0;
  int chroma_subsamp_y = 0;
  int mc_identity = src->mc == AOM_CICP_MC_IDENTITY ? 1 : 0;

  switch (src->fmt) {
    case AOM_IMG_FMT_AOMI420:
    case AOM_IMG_FMT_I420:
      use_high_bit_depth = 0;
      chroma_subsamp_x = 1;
      chroma_subsamp_y = 1;
      break;
    case AOM_IMG_FMT_I42016:
      use_high_bit_depth = 1;
      chroma_subsamp_x = 1;
      chroma_subsamp_y = 1;
      break;
      //    case AOM_IMG_FMT_444A:
    case AOM_IMG_FMT_I444:
      use_high_bit_depth = 0;
      chroma_subsamp_x = 0;
      chroma_subsamp_y = 0;
      break;
    case AOM_IMG_FMT_I44416:
      use_high_bit_depth = 1;
      chroma_subsamp_x = 0;
      chroma_subsamp_y = 0;
      break;
    case AOM_IMG_FMT_I422:
      use_high_bit_depth = 0;
      chroma_subsamp_x = 1;
      chroma_subsamp_y = 0;
      break;
    case AOM_IMG_FMT_I42216:
      use_high_bit_depth = 1;
      chroma_subsamp_x = 1;
      chroma_subsamp_y = 0;
      break;
    default:  // unknown input format
      fprintf(stderr, "Film grain error: input format is not supported!");
      return -1;
  }

  assert(params->bit_depth == src->bit_depth);

  dst->fmt = src->fmt;
  dst->bit_depth = src->bit_depth;

  dst->r_w = src->r_w;
  dst->r_h = src->r_h;
  dst->d_w = src->d_w;
  dst->d_h = src->d_h;

  dst->cp = src->cp;
  dst->tc = src->tc;
  dst->mc = src->mc;

  dst->monochrome = src->monochrome;
  dst->csp = src->csp;
  dst->range = src->range;

  dst->x_chroma_shift = src->x_chroma_shift;
  dst->y_chroma_shift = src->y_chroma_shift;

  dst->temporal_id = src->temporal_id;
  dst->spatial_id = src->spatial_id;

  width = src->d_w % 2 ? src->d_w + 1 : src->d_w;
  height = src->d_h % 2 ? src->d_h + 1 : src->d_h;

  copy_rect(src->planes[AOM_PLANE_Y], src->stride[AOM_PLANE_Y],
            dst->planes[AOM_PLANE_Y], dst->stride[AOM_PLANE_Y], src->d_w,
            src->d_h, use_high_bit_depth);
  // Note that dst is already assumed to be aligned to even.
  extend_even(dst->planes[AOM_PLANE_Y], dst->stride[AOM_PLANE_Y], src->d_w,
              src->d_h, use_high_bit_depth);

  if (!src->monochrome) {
    copy_rect(src->planes[AOM_PLANE_U], src->stride[AOM_PLANE_U],
              dst->planes[AOM_PLANE_U], dst->stride[AOM_PLANE_U],
              width >> chroma_subsamp_x, height >> chroma_subsamp_y,
              use_high_bit_depth);

    copy_rect(src->planes[AOM_PLANE_V], src->stride[AOM_PLANE_V],
              dst->planes[AOM_PLANE_V], dst->stride[AOM_PLANE_V],
              width >> chroma_subsamp_x, height >> chroma_subsamp_y,
              use_high_bit_depth);
  }

  luma = dst->planes[AOM_PLANE_Y];
  cb = dst->planes[AOM_PLANE_U];
  cr = dst->planes[AOM_PLANE_V];

  // luma and chroma strides in samples
  luma_stride = dst->stride[AOM_PLANE_Y] >> use_high_bit_depth;
  chroma_stride = dst->stride[AOM_PLANE_U] >> use_high_bit_depth;

  return av1_add_film_grain_run(
      params, luma, cb, cr, height, width, luma_stride, chroma_stride,
      use_high_bit_depth, chroma_subsamp_y, chroma_subsamp_x, mc_identity);
}

int av1_add_film_grain_run(const aom_film_grain_t *params, uint8_t *luma,
                           uint8_t *cb, uint8_t *cr, int height, int width,
                           int luma_stride, int chroma_stride,
                           int use_high_bit_depth, int chroma_subsamp_y,
                           int chroma_subsamp_x, int mc_identity) {
  int **pred_pos_luma;
  int **pred_pos_chroma;
  int *luma_grain_block;
  int *cb_grain_block;
  int *cr_grain_block;

  int *y_line_buf;
  int *cb_line_buf;
  int *cr_line_buf;

  int *y_col_buf;
  int *cb_col_buf;
  int *cr_col_buf;

  random_register = params->random_seed;

  int left_pad = 3;
  int right_pad = 3;  // padding to offset for AR coefficients
  int top_pad = 3;
  int bottom_pad = 0;

  int ar_padding = 3;  // maximum lag used for stabilization of AR coefficients

  luma_subblock_size_y = 32;
  luma_subblock_size_x = 32;

  chroma_subblock_size_y = luma_subblock_size_y >> chroma_subsamp_y;
  chroma_subblock_size_x = luma_subblock_size_x >> chroma_subsamp_x;

  // Initial padding is only needed for generation of
  // film grain templates (to stabilize the AR process)
  // Only a 64x64 luma and 32x32 chroma part of a template
  // is used later for adding grain, padding can be discarded

  int luma_block_size_y =
      top_pad + 2 * ar_padding + luma_subblock_size_y * 2 + bottom_pad;
  int luma_block_size_x = left_pad + 2 * ar_padding + luma_subblock_size_x * 2 +
                          2 * ar_padding + right_pad;

  int chroma_block_size_y = top_pad + (2 >> chroma_subsamp_y) * ar_padding +
                            chroma_subblock_size_y * 2 + bottom_pad;
  int chroma_block_size_x = left_pad + (2 >> chroma_subsamp_x) * ar_padding +
                            chroma_subblock_size_x * 2 +
                            (2 >> chroma_subsamp_x) * ar_padding + right_pad;

  int luma_grain_stride = luma_block_size_x;
  int chroma_grain_stride = chroma_block_size_x;

  int overlap = params->overlap_flag;
  int bit_depth = params->bit_depth;

  const int grain_center = 128 << (bit_depth - 8);
  grain_min = 0 - grain_center;
  grain_max = grain_center - 1;

  if (!init_arrays(params, luma_stride, chroma_stride, &pred_pos_luma,
                   &pred_pos_chroma, &luma_grain_block, &cb_grain_block,
                   &cr_grain_block, &y_line_buf, &cb_line_buf, &cr_line_buf,
                   &y_col_buf, &cb_col_buf, &cr_col_buf,
                   luma_block_size_y * luma_block_size_x,
                   chroma_block_size_y * chroma_block_size_x, chroma_subsamp_y,
                   chroma_subsamp_x))
    return -1;

  generate_luma_grain_block(params, pred_pos_luma, luma_grain_block,
                            luma_block_size_y, luma_block_size_x,
                            luma_grain_stride, left_pad, top_pad, right_pad,
                            bottom_pad);

  if (!generate_chroma_grain_blocks(
          params, pred_pos_chroma, luma_grain_block, cb_grain_block,
          cr_grain_block, luma_grain_stride, chroma_block_size_y,
          chroma_block_size_x, chroma_grain_stride, left_pad, top_pad,
          right_pad, bottom_pad, chroma_subsamp_y, chroma_subsamp_x))
    return -1;

  init_scaling_function(params->scaling_points_y, params->num_y_points,
                        scaling_lut_y);

  if (params->chroma_scaling_from_luma) {
    memcpy(scaling_lut_cb, scaling_lut_y, sizeof(*scaling_lut_y) * 256);
    memcpy(scaling_lut_cr, scaling_lut_y, sizeof(*scaling_lut_y) * 256);
  } else {
    init_scaling_function(params->scaling_points_cb, params->num_cb_points,
                          scaling_lut_cb);
    init_scaling_function(params->scaling_points_cr, params->num_cr_points,
                          scaling_lut_cr);
  }
  for (int y = 0; y < height / 2; y += (luma_subblock_size_y >> 1)) {
    init_random_generator(y * 2, params->random_seed);

    for (int x = 0; x < width / 2; x += (luma_subblock_size_x >> 1)) {
      int offset_y = get_random_number(8);
      int offset_x = (offset_y >> 4) & 15;
      offset_y &= 15;

      int luma_offset_y = left_pad + 2 * ar_padding + (offset_y << 1);
      int luma_offset_x = top_pad + 2 * ar_padding + (offset_x << 1);

      int chroma_offset_y = top_pad + (2 >> chroma_subsamp_y) * ar_padding +
                            offset_y * (2 >> chroma_subsamp_y);
      int chroma_offset_x = left_pad + (2 >> chroma_subsamp_x) * ar_padding +
                            offset_x * (2 >> chroma_subsamp_x);

      if (overlap && x) {
        ver_boundary_overlap(
            y_col_buf, 2,
            luma_grain_block + luma_offset_y * luma_grain_stride +
                luma_offset_x,
            luma_grain_stride, y_col_buf, 2, 2,
            AOMMIN(luma_subblock_size_y + 2, height - (y << 1)));

        ver_boundary_overlap(
            cb_col_buf, 2 >> chroma_subsamp_x,
            cb_grain_block + chroma_offset_y * chroma_grain_stride +
                chroma_offset_x,
            chroma_grain_stride, cb_col_buf, 2 >> chroma_subsamp_x,
            2 >> chroma_subsamp_x,
            AOMMIN(chroma_subblock_size_y + (2 >> chroma_subsamp_y),
                   (height - (y << 1)) >> chroma_subsamp_y));

        ver_boundary_overlap(
            cr_col_buf, 2 >> chroma_subsamp_x,
            cr_grain_block + chroma_offset_y * chroma_grain_stride +
                chroma_offset_x,
            chroma_grain_stride, cr_col_buf, 2 >> chroma_subsamp_x,
            2 >> chroma_subsamp_x,
            AOMMIN(chroma_subblock_size_y + (2 >> chroma_subsamp_y),
                   (height - (y << 1)) >> chroma_subsamp_y));

        int i = y ? 1 : 0;

        if (use_high_bit_depth) {
          add_noise_to_block_hbd(
              params,
              (uint16_t *)luma + ((y + i) << 1) * luma_stride + (x << 1),
              (uint16_t *)cb +
                  ((y + i) << (1 - chroma_subsamp_y)) * chroma_stride +
                  (x << (1 - chroma_subsamp_x)),
              (uint16_t *)cr +
                  ((y + i) << (1 - chroma_subsamp_y)) * chroma_stride +
                  (x << (1 - chroma_subsamp_x)),
              luma_stride, chroma_stride, y_col_buf + i * 4,
              cb_col_buf + i * (2 - chroma_subsamp_y) * (2 - chroma_subsamp_x),
              cr_col_buf + i * (2 - chroma_subsamp_y) * (2 - chroma_subsamp_x),
              2, (2 - chroma_subsamp_x),
              AOMMIN(luma_subblock_size_y >> 1, height / 2 - y) - i, 1,
              bit_depth, chroma_subsamp_y, chroma_subsamp_x, mc_identity);
        } else {
          add_noise_to_block(
              params, luma + ((y + i) << 1) * luma_stride + (x << 1),
              cb + ((y + i) << (1 - chroma_subsamp_y)) * chroma_stride +
                  (x << (1 - chroma_subsamp_x)),
              cr + ((y + i) << (1 - chroma_subsamp_y)) * chroma_stride +
                  (x << (1 - chroma_subsamp_x)),
              luma_stride, chroma_stride, y_col_buf + i * 4,
              cb_col_buf + i * (2 - chroma_subsamp_y) * (2 - chroma_subsamp_x),
              cr_col_buf + i * (2 - chroma_subsamp_y) * (2 - chroma_subsamp_x),
              2, (2 - chroma_subsamp_x),
              AOMMIN(luma_subblock_size_y >> 1, height / 2 - y) - i, 1,
              bit_depth, chroma_subsamp_y, chroma_subsamp_x, mc_identity);
        }
      }

      if (overlap && y) {
        if (x) {
          hor_boundary_overlap(y_line_buf + (x << 1), luma_stride, y_col_buf, 2,
                               y_line_buf + (x << 1), luma_stride, 2, 2);

          hor_boundary_overlap(cb_line_buf + x * (2 >> chroma_subsamp_x),
                               chroma_stride, cb_col_buf, 2 >> chroma_subsamp_x,
                               cb_line_buf + x * (2 >> chroma_subsamp_x),
                               chroma_stride, 2 >> chroma_subsamp_x,
                               2 >> chroma_subsamp_y);

          hor_boundary_overlap(cr_line_buf + x * (2 >> chroma_subsamp_x),
                               chroma_stride, cr_col_buf, 2 >> chroma_subsamp_x,
                               cr_line_buf + x * (2 >> chroma_subsamp_x),
                               chroma_stride, 2 >> chroma_subsamp_x,
                               2 >> chroma_subsamp_y);
        }

        hor_boundary_overlap(
            y_line_buf + ((x ? x + 1 : 0) << 1), luma_stride,
            luma_grain_block + luma_offset_y * luma_grain_stride +
                luma_offset_x + (x ? 2 : 0),
            luma_grain_stride, y_line_buf + ((x ? x + 1 : 0) << 1), luma_stride,
            AOMMIN(luma_subblock_size_x - ((x ? 1 : 0) << 1),
                   width - ((x ? x + 1 : 0) << 1)),
            2);

        hor_boundary_overlap(
            cb_line_buf + ((x ? x + 1 : 0) << (1 - chroma_subsamp_x)),
            chroma_stride,
            cb_grain_block + chroma_offset_y * chroma_grain_stride +
                chroma_offset_x + ((x ? 1 : 0) << (1 - chroma_subsamp_x)),
            chroma_grain_stride,
            cb_line_buf + ((x ? x + 1 : 0) << (1 - chroma_subsamp_x)),
            chroma_stride,
            AOMMIN(chroma_subblock_size_x -
                       ((x ? 1 : 0) << (1 - chroma_subsamp_x)),
                   (width - ((x ? x + 1 : 0) << 1)) >> chroma_subsamp_x),
            2 >> chroma_subsamp_y);

        hor_boundary_overlap(
            cr_line_buf + ((x ? x + 1 : 0) << (1 - chroma_subsamp_x)),
            chroma_stride,
            cr_grain_block + chroma_offset_y * chroma_grain_stride +
                chroma_offset_x + ((x ? 1 : 0) << (1 - chroma_subsamp_x)),
            chroma_grain_stride,
            cr_line_buf + ((x ? x + 1 : 0) << (1 - chroma_subsamp_x)),
            chroma_stride,
            AOMMIN(chroma_subblock_size_x -
                       ((x ? 1 : 0) << (1 - chroma_subsamp_x)),
                   (width - ((x ? x + 1 : 0) << 1)) >> chroma_subsamp_x),
            2 >> chroma_subsamp_y);

        if (use_high_bit_depth) {
          add_noise_to_block_hbd(
              params, (uint16_t *)luma + (y << 1) * luma_stride + (x << 1),
              (uint16_t *)cb + (y << (1 - chroma_subsamp_y)) * chroma_stride +
                  (x << ((1 - chroma_subsamp_x))),
              (uint16_t *)cr + (y << (1 - chroma_subsamp_y)) * chroma_stride +
                  (x << ((1 - chroma_subsamp_x))),
              luma_stride, chroma_stride, y_line_buf + (x << 1),
              cb_line_buf + (x << (1 - chroma_subsamp_x)),
              cr_line_buf + (x << (1 - chroma_subsamp_x)), luma_stride,
              chroma_stride, 1,
              AOMMIN(luma_subblock_size_x >> 1, width / 2 - x), bit_depth,
              chroma_subsamp_y, chroma_subsamp_x, mc_identity);
        } else {
          add_noise_to_block(
              params, luma + (y << 1) * luma_stride + (x << 1),
              cb + (y << (1 - chroma_subsamp_y)) * chroma_stride +
                  (x << ((1 - chroma_subsamp_x))),
              cr + (y << (1 - chroma_subsamp_y)) * chroma_stride +
                  (x << ((1 - chroma_subsamp_x))),
              luma_stride, chroma_stride, y_line_buf + (x << 1),
              cb_line_buf + (x << (1 - chroma_subsamp_x)),
              cr_line_buf + (x << (1 - chroma_subsamp_x)), luma_stride,
              chroma_stride, 1,
              AOMMIN(luma_subblock_size_x >> 1, width / 2 - x), bit_depth,
              chroma_subsamp_y, chroma_subsamp_x, mc_identity);
        }
      }

      int i = overlap && y ? 1 : 0;
      int j = overlap && x ? 1 : 0;

      if (use_high_bit_depth) {
        add_noise_to_block_hbd(
            params,
            (uint16_t *)luma + ((y + i) << 1) * luma_stride + ((x + j) << 1),
            (uint16_t *)cb +
                ((y + i) << (1 - chroma_subsamp_y)) * chroma_stride +
                ((x + j) << (1 - chroma_subsamp_x)),
            (uint16_t *)cr +
                ((y + i) << (1 - chroma_subsamp_y)) * chroma_stride +
                ((x + j) << (1 - chroma_subsamp_x)),
            luma_stride, chroma_stride,
            luma_grain_block + (luma_offset_y + (i << 1)) * luma_grain_stride +
                luma_offset_x + (j << 1),
            cb_grain_block +
                (chroma_offset_y + (i << (1 - chroma_subsamp_y))) *
                    chroma_grain_stride +
                chroma_offset_x + (j << (1 - chroma_subsamp_x)),
            cr_grain_block +
                (chroma_offset_y + (i << (1 - chroma_subsamp_y))) *
                    chroma_grain_stride +
                chroma_offset_x + (j << (1 - chroma_subsamp_x)),
            luma_grain_stride, chroma_grain_stride,
            AOMMIN(luma_subblock_size_y >> 1, height / 2 - y) - i,
            AOMMIN(luma_subblock_size_x >> 1, width / 2 - x) - j, bit_depth,
            chroma_subsamp_y, chroma_subsamp_x, mc_identity);
      } else {
        add_noise_to_block(
            params, luma + ((y + i) << 1) * luma_stride + ((x + j) << 1),
            cb + ((y + i) << (1 - chroma_subsamp_y)) * chroma_stride +
                ((x + j) << (1 - chroma_subsamp_x)),
            cr + ((y + i) << (1 - chroma_subsamp_y)) * chroma_stride +
                ((x + j) << (1 - chroma_subsamp_x)),
            luma_stride, chroma_stride,
            luma_grain_block + (luma_offset_y + (i << 1)) * luma_grain_stride +
                luma_offset_x + (j << 1),
            cb_grain_block +
                (chroma_offset_y + (i << (1 - chroma_subsamp_y))) *
                    chroma_grain_stride +
                chroma_offset_x + (j << (1 - chroma_subsamp_x)),
            cr_grain_block +
                (chroma_offset_y + (i << (1 - chroma_subsamp_y))) *
                    chroma_grain_stride +
                chroma_offset_x + (j << (1 - chroma_subsamp_x)),
            luma_grain_stride, chroma_grain_stride,
            AOMMIN(luma_subblock_size_y >> 1, height / 2 - y) - i,
            AOMMIN(luma_subblock_size_x >> 1, width / 2 - x) - j, bit_depth,
            chroma_subsamp_y, chroma_subsamp_x, mc_identity);
      }

      if (overlap) {
        if (x) {
          // Copy overlapped column bufer to line buffer
          copy_area(y_col_buf + (luma_subblock_size_y << 1), 2,
                    y_line_buf + (x << 1), luma_stride, 2, 2);

          copy_area(
              cb_col_buf + (chroma_subblock_size_y << (1 - chroma_subsamp_x)),
              2 >> chroma_subsamp_x,
              cb_line_buf + (x << (1 - chroma_subsamp_x)), chroma_stride,
              2 >> chroma_subsamp_x, 2 >> chroma_subsamp_y);

          copy_area(
              cr_col_buf + (chroma_subblock_size_y << (1 - chroma_subsamp_x)),
              2 >> chroma_subsamp_x,
              cr_line_buf + (x << (1 - chroma_subsamp_x)), chroma_stride,
              2 >> chroma_subsamp_x, 2 >> chroma_subsamp_y);
        }

        // Copy grain to the line buffer for overlap with a bottom block
        copy_area(
            luma_grain_block +
                (luma_offset_y + luma_subblock_size_y) * luma_grain_stride +
                luma_offset_x + ((x ? 2 : 0)),
            luma_grain_stride, y_line_buf + ((x ? x + 1 : 0) << 1), luma_stride,
            AOMMIN(luma_subblock_size_x, width - (x << 1)) - (x ? 2 : 0), 2);

        copy_area(cb_grain_block +
                      (chroma_offset_y + chroma_subblock_size_y) *
                          chroma_grain_stride +
                      chroma_offset_x + (x ? 2 >> chroma_subsamp_x : 0),
                  chroma_grain_stride,
                  cb_line_buf + ((x ? x + 1 : 0) << (1 - chroma_subsamp_x)),
                  chroma_stride,
                  AOMMIN(chroma_subblock_size_x,
                         ((width - (x << 1)) >> chroma_subsamp_x)) -
                      (x ? 2 >> chroma_subsamp_x : 0),
                  2 >> chroma_subsamp_y);

        copy_area(cr_grain_block +
                      (chroma_offset_y + chroma_subblock_size_y) *
                          chroma_grain_stride +
                      chroma_offset_x + (x ? 2 >> chroma_subsamp_x : 0),
                  chroma_grain_stride,
                  cr_line_buf + ((x ? x + 1 : 0) << (1 - chroma_subsamp_x)),
                  chroma_stride,
                  AOMMIN(chroma_subblock_size_x,
                         ((width - (x << 1)) >> chroma_subsamp_x)) -
                      (x ? 2 >> chroma_subsamp_x : 0),
                  2 >> chroma_subsamp_y);

        // Copy grain to the column buffer for overlap with the next block to
        // the right

        copy_area(luma_grain_block + luma_offset_y * luma_grain_stride +
                      luma_offset_x + luma_subblock_size_x,
                  luma_grain_stride, y_col_buf, 2, 2,
                  AOMMIN(luma_subblock_size_y + 2, height - (y << 1)));

        copy_area(cb_grain_block + chroma_offset_y * chroma_grain_stride +
                      chroma_offset_x + chroma_subblock_size_x,
                  chroma_grain_stride, cb_col_buf, 2 >> chroma_subsamp_x,
                  2 >> chroma_subsamp_x,
                  AOMMIN(chroma_subblock_size_y + (2 >> chroma_subsamp_y),
                         (height - (y << 1)) >> chroma_subsamp_y));

        copy_area(cr_grain_block + chroma_offset_y * chroma_grain_stride +
                      chroma_offset_x + chroma_subblock_size_x,
                  chroma_grain_stride, cr_col_buf, 2 >> chroma_subsamp_x,
                  2 >> chroma_subsamp_x,
                  AOMMIN(chroma_subblock_size_y + (2 >> chroma_subsamp_y),
                         (height - (y << 1)) >> chroma_subsamp_y));
      }
    }
  }

  dealloc_arrays(params, &pred_pos_luma, &pred_pos_chroma, &luma_grain_block,
                 &cb_grain_block, &cr_grain_block, &y_line_buf, &cb_line_buf,
                 &cr_line_buf, &y_col_buf, &cb_col_buf, &cr_col_buf);
  return 0;
}