third_party/libdav1d/src/filmgrain_tmpl.c - cobalt - Git at Google

 /*
  * Copyright © 2018, Niklas Haas
  * Copyright © 2018, VideoLAN and dav1d authors
  * Copyright © 2018, Two Orioles, LLC
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  * 1. Redistributions of source code must retain the above copyright notice, this
  *    list of conditions and the following disclaimer.
  *
  * 2. Redistributions in binary form must reproduce the above copyright notice,
  *    this list of conditions and the following disclaimer in the documentation
  *    and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 #include "common/attributes.h"
 #include "common/intops.h"

 #include "src/filmgrain.h"
 #include "src/tables.h"

 #define SUB_GRAIN_WIDTH 44
 #define SUB_GRAIN_HEIGHT 38

 static inline int get_random_number(const int bits, unsigned *const state) {
     const int r = *state;
     unsigned bit = ((r >> 0) ^ (r >> 1) ^ (r >> 3) ^ (r >> 12)) & 1;
     *state = (r >> 1) | (bit << 15);

     return (*state >> (16 - bits)) & ((1 << bits) - 1);
 }

 static inline int round2(const int x, const uint64_t shift) {
     return (x + ((1 << shift) >> 1)) >> shift;
 }

 static void generate_grain_y_c(entry buf[][GRAIN_WIDTH],
                                const Dav1dFilmGrainData *const data
                                HIGHBD_DECL_SUFFIX)
 {
     const int bitdepth_min_8 = bitdepth_from_max(bitdepth_max) - 8;
     unsigned seed = data->seed;
     const int shift = 4 - bitdepth_min_8 + data->grain_scale_shift;
     const int grain_ctr = 128 << bitdepth_min_8;
     const int grain_min = -grain_ctr, grain_max = grain_ctr - 1;

     for (int y = 0; y < GRAIN_HEIGHT; y++) {
         for (int x = 0; x < GRAIN_WIDTH; x++) {
             const int value = get_random_number(11, &seed);
             buf[y][x] = round2(dav1d_gaussian_sequence[ value ], shift);
         }
     }

     const int ar_pad = 3;
     const int ar_lag = data->ar_coeff_lag;

     for (int y = ar_pad; y < GRAIN_HEIGHT; y++) {
         for (int x = ar_pad; x < GRAIN_WIDTH - ar_pad; x++) {
             const int8_t *coeff = data->ar_coeffs_y;
             int sum = 0;
             for (int dy = -ar_lag; dy <= 0; dy++) {
                 for (int dx = -ar_lag; dx <= ar_lag; dx++) {
                     if (!dx && !dy)
                         break;
                     sum += *(coeff++) * buf[y + dy][x + dx];
                 }
             }

             const int grain = buf[y][x] + round2(sum, data->ar_coeff_shift);
             buf[y][x] = iclip(grain, grain_min, grain_max);
         }
     }
 }

 static NOINLINE void
 generate_grain_uv_c(entry buf[][GRAIN_WIDTH],
                     const entry buf_y[][GRAIN_WIDTH],
                     const Dav1dFilmGrainData *const data, const intptr_t uv,
                     const int subx, const int suby HIGHBD_DECL_SUFFIX)
 {
     const int bitdepth_min_8 = bitdepth_from_max(bitdepth_max) - 8;
     unsigned seed = data->seed ^ (uv ? 0x49d8 : 0xb524);
     const int shift = 4 - bitdepth_min_8 + data->grain_scale_shift;
     const int grain_ctr = 128 << bitdepth_min_8;
     const int grain_min = -grain_ctr, grain_max = grain_ctr - 1;

     const int chromaW = subx ? SUB_GRAIN_WIDTH  : GRAIN_WIDTH;
     const int chromaH = suby ? SUB_GRAIN_HEIGHT : GRAIN_HEIGHT;

     for (int y = 0; y < chromaH; y++) {
         for (int x = 0; x < chromaW; x++) {
             const int value = get_random_number(11, &seed);
             buf[y][x] = round2(dav1d_gaussian_sequence[ value ], shift);
         }
     }

     const int ar_pad = 3;
     const int ar_lag = data->ar_coeff_lag;

     for (int y = ar_pad; y < chromaH; y++) {
         for (int x = ar_pad; x < chromaW - ar_pad; x++) {
             const int8_t *coeff = data->ar_coeffs_uv[uv];
             int sum = 0;
             for (int dy = -ar_lag; dy <= 0; dy++) {
                 for (int dx = -ar_lag; dx <= ar_lag; dx++) {
                     // For the final (current) pixel, we need to add in the
                     // contribution from the luma grain texture
                     if (!dx && !dy) {
                         if (!data->num_y_points)
                             break;
                         int luma = 0;
                         const int lumaX = ((x - ar_pad) << subx) + ar_pad;
                         const int lumaY = ((y - ar_pad) << suby) + ar_pad;
                         for (int i = 0; i <= suby; i++) {
                             for (int j = 0; j <= subx; j++) {
                                 luma += buf_y[lumaY + i][lumaX + j];
                             }
                         }
                         luma = round2(luma, subx + suby);
                         sum += luma * (*coeff);
                         break;
                     }

                     sum += *(coeff++) * buf[y + dy][x + dx];
                 }
             }

             const int grain = buf[y][x] + round2(sum, data->ar_coeff_shift);
             buf[y][x] = iclip(grain, grain_min, grain_max);
         }
     }
 }

 #define gnuv_ss_fn(nm, ss_x, ss_y) \
 static decl_generate_grain_uv_fn(generate_grain_uv_##nm##_c) { \
     generate_grain_uv_c(buf, buf_y, data, uv, ss_x, ss_y HIGHBD_TAIL_SUFFIX); \
 }

 gnuv_ss_fn(420, 1, 1);
 gnuv_ss_fn(422, 1, 0);
 gnuv_ss_fn(444, 0, 0);

 // samples from the correct block of a grain LUT, while taking into account the
 // offsets provided by the offsets cache
 static inline entry sample_lut(const entry grain_lut[][GRAIN_WIDTH],
                                const int offsets[2][2], const int subx, const int suby,
                                const int bx, const int by, const int x, const int y)
 {
     const int randval = offsets[bx][by];
     const int offx = 3 + (2 >> subx) * (3 + (randval >> 4));
     const int offy = 3 + (2 >> suby) * (3 + (randval & 0xF));
     return grain_lut[offy + y + (BLOCK_SIZE >> suby) * by]
                     [offx + x + (BLOCK_SIZE >> subx) * bx];
 }

 static void fgy_32x32xn_c(pixel *const dst_row, const pixel *const src_row,
                           const ptrdiff_t stride,
                           const Dav1dFilmGrainData *const data, const size_t pw,
                           const uint8_t scaling[SCALING_SIZE],
                           const entry grain_lut[][GRAIN_WIDTH],
                           const int bh, const int row_num HIGHBD_DECL_SUFFIX)
 {
     const int rows = 1 + (data->overlap_flag && row_num > 0);
     const int bitdepth_min_8 = bitdepth_from_max(bitdepth_max) - 8;
     const int grain_ctr = 128 << bitdepth_min_8;
     const int grain_min = -grain_ctr, grain_max = grain_ctr - 1;

     int min_value, max_value;
     if (data->clip_to_restricted_range) {
         min_value = 16 << bitdepth_min_8;
         max_value = 235 << bitdepth_min_8;
     } else {
         min_value = 0;
         max_value = BITDEPTH_MAX;
     }

     // seed[0] contains the current row, seed[1] contains the previous
     unsigned seed[2];
     for (int i = 0; i < rows; i++) {
         seed[i] = data->seed;
         seed[i] ^= (((row_num - i) * 37  + 178) & 0xFF) << 8;
         seed[i] ^= (((row_num - i) * 173 + 105) & 0xFF);
     }

     assert(stride % (BLOCK_SIZE * sizeof(pixel)) == 0);

     int offsets[2 /* col offset */][2 /* row offset */];

     // process this row in BLOCK_SIZE^2 blocks
     for (unsigned bx = 0; bx < pw; bx += BLOCK_SIZE) {
         const int bw = imin(BLOCK_SIZE, (int) pw - bx);

         if (data->overlap_flag && bx) {
             // shift previous offsets left
             for (int i = 0; i < rows; i++)
                 offsets[1][i] = offsets[0][i];
         }

         // update current offsets
         for (int i = 0; i < rows; i++)
             offsets[0][i] = get_random_number(8, &seed[i]);

         // x/y block offsets to compensate for overlapped regions
         const int ystart = data->overlap_flag && row_num ? imin(2, bh) : 0;
         const int xstart = data->overlap_flag && bx      ? imin(2, bw) : 0;

         static const int w[2][2] = { { 27, 17 }, { 17, 27 } };

 #define add_noise_y(x, y, grain)                                                  \
         const pixel *const src = src_row + (y) * PXSTRIDE(stride) + (x) + bx;     \
         pixel *const dst = dst_row + (y) * PXSTRIDE(stride) + (x) + bx;           \
         const int noise = round2(scaling[ *src ] * (grain), data->scaling_shift); \
         *dst = iclip(*src + noise, min_value, max_value);

         for (int y = ystart; y < bh; y++) {
             // Non-overlapped image region (straightforward)
             for (int x = xstart; x < bw; x++) {
                 int grain = sample_lut(grain_lut, offsets, 0, 0, 0, 0, x, y);
                 add_noise_y(x, y, grain);
             }

             // Special case for overlapped column
             for (int x = 0; x < xstart; x++) {
                 int grain = sample_lut(grain_lut, offsets, 0, 0, 0, 0, x, y);
                 int old   = sample_lut(grain_lut, offsets, 0, 0, 1, 0, x, y);
                 grain = round2(old * w[x][0] + grain * w[x][1], 5);
                 grain = iclip(grain, grain_min, grain_max);
                 add_noise_y(x, y, grain);
             }
         }

         for (int y = 0; y < ystart; y++) {
             // Special case for overlapped row (sans corner)
             for (int x = xstart; x < bw; x++) {
                 int grain = sample_lut(grain_lut, offsets, 0, 0, 0, 0, x, y);
                 int old   = sample_lut(grain_lut, offsets, 0, 0, 0, 1, x, y);
                 grain = round2(old * w[y][0] + grain * w[y][1], 5);
                 grain = iclip(grain, grain_min, grain_max);
                 add_noise_y(x, y, grain);
             }

             // Special case for doubly-overlapped corner
             for (int x = 0; x < xstart; x++) {
                 // Blend the top pixel with the top left block
                 int top = sample_lut(grain_lut, offsets, 0, 0, 0, 1, x, y);
                 int old = sample_lut(grain_lut, offsets, 0, 0, 1, 1, x, y);
                 top = round2(old * w[x][0] + top * w[x][1], 5);
                 top = iclip(top, grain_min, grain_max);

                 // Blend the current pixel with the left block
                 int grain = sample_lut(grain_lut, offsets, 0, 0, 0, 0, x, y);
                 old = sample_lut(grain_lut, offsets, 0, 0, 1, 0, x, y);
                 grain = round2(old * w[x][0] + grain * w[x][1], 5);
                 grain = iclip(grain, grain_min, grain_max);

                 // Mix the row rows together and apply grain
                 grain = round2(top * w[y][0] + grain * w[y][1], 5);
                 grain = iclip(grain, grain_min, grain_max);
                 add_noise_y(x, y, grain);
             }
         }
     }
 }

 static NOINLINE void
 fguv_32x32xn_c(pixel *const dst_row, const pixel *const src_row,
                const ptrdiff_t stride, const Dav1dFilmGrainData *const data,
                const size_t pw, const uint8_t scaling[SCALING_SIZE],
                const entry grain_lut[][GRAIN_WIDTH], const int bh,
                const int row_num, const pixel *const luma_row,
                const ptrdiff_t luma_stride, const int uv, const int is_id,
                const int sx, const int sy HIGHBD_DECL_SUFFIX)
 {
     const int rows = 1 + (data->overlap_flag && row_num > 0);
     const int bitdepth_min_8 = bitdepth_from_max(bitdepth_max) - 8;
     const int grain_ctr = 128 << bitdepth_min_8;
     const int grain_min = -grain_ctr, grain_max = grain_ctr - 1;

     int min_value, max_value;
     if (data->clip_to_restricted_range) {
         min_value = 16 << bitdepth_min_8;
         max_value = (is_id ? 235 : 240) << bitdepth_min_8;
     } else {
         min_value = 0;
         max_value = BITDEPTH_MAX;
     }

     // seed[0] contains the current row, seed[1] contains the previous
     unsigned seed[2];
     for (int i = 0; i < rows; i++) {
         seed[i] = data->seed;
         seed[i] ^= (((row_num - i) * 37  + 178) & 0xFF) << 8;
         seed[i] ^= (((row_num - i) * 173 + 105) & 0xFF);
     }

     assert(stride % (BLOCK_SIZE * sizeof(pixel)) == 0);

     int offsets[2 /* col offset */][2 /* row offset */];

     // process this row in BLOCK_SIZE^2 blocks (subsampled)
     for (unsigned bx = 0; bx < pw; bx += BLOCK_SIZE >> sx) {
         const int bw = imin(BLOCK_SIZE >> sx, (int)(pw - bx));
         if (data->overlap_flag && bx) {
             // shift previous offsets left
             for (int i = 0; i < rows; i++)
                 offsets[1][i] = offsets[0][i];
         }

         // update current offsets
         for (int i = 0; i < rows; i++)
             offsets[0][i] = get_random_number(8, &seed[i]);

         // x/y block offsets to compensate for overlapped regions
         const int ystart = data->overlap_flag && row_num ? imin(2 >> sy, bh) : 0;
         const int xstart = data->overlap_flag && bx      ? imin(2 >> sx, bw) : 0;

         static const int w[2 /* sub */][2 /* off */][2] = {
             { { 27, 17 }, { 17, 27 } },
             { { 23, 22 } },
         };

 #define add_noise_uv(x, y, grain)                                                    \
             const int lx = (bx + x) << sx;                                           \
             const int ly = y << sy;                                                  \
             const pixel *const luma = luma_row + ly * PXSTRIDE(luma_stride) + lx;    \
             pixel avg = luma[0];                                                     \
             if (sx)                                                                  \
                 avg = (avg + luma[1] + 1) >> 1;                                      \
             const pixel *const src = src_row + (y) * PXSTRIDE(stride) + (bx + (x));  \
             pixel *const dst = dst_row + (y) * PXSTRIDE(stride) + (bx + (x));        \
             int val = avg;                                                           \
             if (!data->chroma_scaling_from_luma) {                                   \
                 const int combined = avg * data->uv_luma_mult[uv] +                  \
                                *src * data->uv_mult[uv];                             \
                 val = iclip_pixel( (combined >> 6) +                                 \
                                    (data->uv_offset[uv] * (1 << bitdepth_min_8)) );  \
             }                                                                        \
             const int noise = round2(scaling[ val ] * (grain), data->scaling_shift); \
             *dst = iclip(*src + noise, min_value, max_value);

         for (int y = ystart; y < bh; y++) {
             // Non-overlapped image region (straightforward)
             for (int x = xstart; x < bw; x++) {
                 int grain = sample_lut(grain_lut, offsets, sx, sy, 0, 0, x, y);
                 add_noise_uv(x, y, grain);
             }

             // Special case for overlapped column
             for (int x = 0; x < xstart; x++) {
                 int grain = sample_lut(grain_lut, offsets, sx, sy, 0, 0, x, y);
                 int old   = sample_lut(grain_lut, offsets, sx, sy, 1, 0, x, y);
                 grain = round2(old * w[sx][x][0] + grain * w[sx][x][1], 5);
                 grain = iclip(grain, grain_min, grain_max);
                 add_noise_uv(x, y, grain);
             }
         }

         for (int y = 0; y < ystart; y++) {
             // Special case for overlapped row (sans corner)
             for (int x = xstart; x < bw; x++) {
                 int grain = sample_lut(grain_lut, offsets, sx, sy, 0, 0, x, y);
                 int old   = sample_lut(grain_lut, offsets, sx, sy, 0, 1, x, y);
                 grain = round2(old * w[sy][y][0] + grain * w[sy][y][1], 5);
                 grain = iclip(grain, grain_min, grain_max);
                 add_noise_uv(x, y, grain);
             }

             // Special case for doubly-overlapped corner
             for (int x = 0; x < xstart; x++) {
                 // Blend the top pixel with the top left block
                 int top = sample_lut(grain_lut, offsets, sx, sy, 0, 1, x, y);
                 int old = sample_lut(grain_lut, offsets, sx, sy, 1, 1, x, y);
                 top = round2(old * w[sx][x][0] + top * w[sx][x][1], 5);
                 top = iclip(top, grain_min, grain_max);

                 // Blend the current pixel with the left block
                 int grain = sample_lut(grain_lut, offsets, sx, sy, 0, 0, x, y);
                 old = sample_lut(grain_lut, offsets, sx, sy, 1, 0, x, y);
                 grain = round2(old * w[sx][x][0] + grain * w[sx][x][1], 5);
                 grain = iclip(grain, grain_min, grain_max);

                 // Mix the row rows together and apply to image
                 grain = round2(top * w[sy][y][0] + grain * w[sy][y][1], 5);
                 grain = iclip(grain, grain_min, grain_max);
                 add_noise_uv(x, y, grain);
             }
         }
     }
 }

 #define fguv_ss_fn(nm, ss_x, ss_y) \
 static decl_fguv_32x32xn_fn(fguv_32x32xn_##nm##_c) { \
     fguv_32x32xn_c(dst_row, src_row, stride, data, pw, scaling, grain_lut, bh, \
                    row_num, luma_row, luma_stride, uv_pl, is_id, ss_x, ss_y \
                    HIGHBD_TAIL_SUFFIX); \
 }

 fguv_ss_fn(420, 1, 1);
 fguv_ss_fn(422, 1, 0);
 fguv_ss_fn(444, 0, 0);

 #if HAVE_ASM
 #if ARCH_AARCH64 || ARCH_ARM
 #include "src/arm/filmgrain.h"
 #elif ARCH_X86
 #include "src/x86/filmgrain.h"
 #endif
 #endif

 COLD void bitfn(dav1d_film_grain_dsp_init)(Dav1dFilmGrainDSPContext *const c) {
     c->generate_grain_y = generate_grain_y_c;
     c->generate_grain_uv[DAV1D_PIXEL_LAYOUT_I420 - 1] = generate_grain_uv_420_c;
     c->generate_grain_uv[DAV1D_PIXEL_LAYOUT_I422 - 1] = generate_grain_uv_422_c;
     c->generate_grain_uv[DAV1D_PIXEL_LAYOUT_I444 - 1] = generate_grain_uv_444_c;

     c->fgy_32x32xn = fgy_32x32xn_c;
     c->fguv_32x32xn[DAV1D_PIXEL_LAYOUT_I420 - 1] = fguv_32x32xn_420_c;
     c->fguv_32x32xn[DAV1D_PIXEL_LAYOUT_I422 - 1] = fguv_32x32xn_422_c;
     c->fguv_32x32xn[DAV1D_PIXEL_LAYOUT_I444 - 1] = fguv_32x32xn_444_c;

 #if HAVE_ASM
 #if ARCH_AARCH64 || ARCH_ARM
     film_grain_dsp_init_arm(c);
 #elif ARCH_X86
     film_grain_dsp_init_x86(c);
 #endif
 #endif
 }
	/*
	* Copyright © 2018, Niklas Haas
	* Copyright © 2018, VideoLAN and dav1d authors
	* Copyright © 2018, Two Orioles, LLC
	* All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions are met:
	*
	* 1. Redistributions of source code must retain the above copyright notice, this
	* list of conditions and the following disclaimer.
	*
	* 2. Redistributions in binary form must reproduce the above copyright notice,
	* this list of conditions and the following disclaimer in the documentation
	* and/or other materials provided with the distribution.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
	* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
	* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
	* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
	* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
	* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
	* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
	* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	#include "common/attributes.h"
	#include "common/intops.h"

	#include "src/filmgrain.h"
	#include "src/tables.h"

	#define SUB_GRAIN_WIDTH 44
	#define SUB_GRAIN_HEIGHT 38

	static inline int get_random_number(const int bits, unsigned *const state) {
	const int r = *state;
	unsigned bit = ((r >> 0) ^ (r >> 1) ^ (r >> 3) ^ (r >> 12)) & 1;
	*state = (r >> 1) \| (bit << 15);

	return (*state >> (16 - bits)) & ((1 << bits) - 1);
	}

	static inline int round2(const int x, const uint64_t shift) {
	return (x + ((1 << shift) >> 1)) >> shift;
	}

	static void generate_grain_y_c(entry buf[][GRAIN_WIDTH],
	const Dav1dFilmGrainData *const data
	HIGHBD_DECL_SUFFIX)
	{
	const int bitdepth_min_8 = bitdepth_from_max(bitdepth_max) - 8;
	unsigned seed = data->seed;
	const int shift = 4 - bitdepth_min_8 + data->grain_scale_shift;
	const int grain_ctr = 128 << bitdepth_min_8;
	const int grain_min = -grain_ctr, grain_max = grain_ctr - 1;

	for (int y = 0; y < GRAIN_HEIGHT; y++) {
	for (int x = 0; x < GRAIN_WIDTH; x++) {
	const int value = get_random_number(11, &seed);
	buf[y][x] = round2(dav1d_gaussian_sequence[ value ], shift);
	}
	}

	const int ar_pad = 3;
	const int ar_lag = data->ar_coeff_lag;

	for (int y = ar_pad; y < GRAIN_HEIGHT; y++) {
	for (int x = ar_pad; x < GRAIN_WIDTH - ar_pad; x++) {
	const int8_t *coeff = data->ar_coeffs_y;
	int sum = 0;
	for (int dy = -ar_lag; dy <= 0; dy++) {
	for (int dx = -ar_lag; dx <= ar_lag; dx++) {
	if (!dx && !dy)
	break;
	sum += (coeff++) buf[y + dy][x + dx];
	}
	}

	const int grain = buf[y][x] + round2(sum, data->ar_coeff_shift);
	buf[y][x] = iclip(grain, grain_min, grain_max);
	}
	}
	}

	static NOINLINE void
	generate_grain_uv_c(entry buf[][GRAIN_WIDTH],
	const entry buf_y[][GRAIN_WIDTH],
	const Dav1dFilmGrainData *const data, const intptr_t uv,
	const int subx, const int suby HIGHBD_DECL_SUFFIX)
	{
	const int bitdepth_min_8 = bitdepth_from_max(bitdepth_max) - 8;
	unsigned seed = data->seed ^ (uv ? 0x49d8 : 0xb524);
	const int shift = 4 - bitdepth_min_8 + data->grain_scale_shift;
	const int grain_ctr = 128 << bitdepth_min_8;
	const int grain_min = -grain_ctr, grain_max = grain_ctr - 1;

	const int chromaW = subx ? SUB_GRAIN_WIDTH : GRAIN_WIDTH;
	const int chromaH = suby ? SUB_GRAIN_HEIGHT : GRAIN_HEIGHT;

	for (int y = 0; y < chromaH; y++) {
	for (int x = 0; x < chromaW; x++) {
	const int value = get_random_number(11, &seed);
	buf[y][x] = round2(dav1d_gaussian_sequence[ value ], shift);
	}
	}

	const int ar_pad = 3;
	const int ar_lag = data->ar_coeff_lag;

	for (int y = ar_pad; y < chromaH; y++) {
	for (int x = ar_pad; x < chromaW - ar_pad; x++) {
	const int8_t *coeff = data->ar_coeffs_uv[uv];
	int sum = 0;
	for (int dy = -ar_lag; dy <= 0; dy++) {
	for (int dx = -ar_lag; dx <= ar_lag; dx++) {
	// For the final (current) pixel, we need to add in the
	// contribution from the luma grain texture
	if (!dx && !dy) {
	if (!data->num_y_points)
	break;
	int luma = 0;
	const int lumaX = ((x - ar_pad) << subx) + ar_pad;
	const int lumaY = ((y - ar_pad) << suby) + ar_pad;
	for (int i = 0; i <= suby; i++) {
	for (int j = 0; j <= subx; j++) {
	luma += buf_y[lumaY + i][lumaX + j];
	}
	}
	luma = round2(luma, subx + suby);
	sum += luma * (*coeff);
	break;
	}

	sum += (coeff++) buf[y + dy][x + dx];
	}
	}

	const int grain = buf[y][x] + round2(sum, data->ar_coeff_shift);
	buf[y][x] = iclip(grain, grain_min, grain_max);
	}
	}
	}

	#define gnuv_ss_fn(nm, ss_x, ss_y) \
	static decl_generate_grain_uv_fn(generate_grain_uv_##nm##_c) { \
	generate_grain_uv_c(buf, buf_y, data, uv, ss_x, ss_y HIGHBD_TAIL_SUFFIX); \
	}

	gnuv_ss_fn(420, 1, 1);
	gnuv_ss_fn(422, 1, 0);
	gnuv_ss_fn(444, 0, 0);

	// samples from the correct block of a grain LUT, while taking into account the
	// offsets provided by the offsets cache
	static inline entry sample_lut(const entry grain_lut[][GRAIN_WIDTH],
	const int offsets[2][2], const int subx, const int suby,
	const int bx, const int by, const int x, const int y)
	{
	const int randval = offsets[bx][by];
	const int offx = 3 + (2 >> subx) * (3 + (randval >> 4));
	const int offy = 3 + (2 >> suby) * (3 + (randval & 0xF));
	return grain_lut[offy + y + (BLOCK_SIZE >> suby) * by]
	[offx + x + (BLOCK_SIZE >> subx) * bx];
	}

	static void fgy_32x32xn_c(pixel const dst_row, const pixel const src_row,
	const ptrdiff_t stride,
	const Dav1dFilmGrainData *const data, const size_t pw,
	const uint8_t scaling[SCALING_SIZE],
	const entry grain_lut[][GRAIN_WIDTH],
	const int bh, const int row_num HIGHBD_DECL_SUFFIX)
	{
	const int rows = 1 + (data->overlap_flag && row_num > 0);
	const int bitdepth_min_8 = bitdepth_from_max(bitdepth_max) - 8;
	const int grain_ctr = 128 << bitdepth_min_8;
	const int grain_min = -grain_ctr, grain_max = grain_ctr - 1;

	int min_value, max_value;
	if (data->clip_to_restricted_range) {
	min_value = 16 << bitdepth_min_8;
	max_value = 235 << bitdepth_min_8;
	} else {
	min_value = 0;
	max_value = BITDEPTH_MAX;
	}

	// seed[0] contains the current row, seed[1] contains the previous
	unsigned seed[2];
	for (int i = 0; i < rows; i++) {
	seed[i] = data->seed;
	seed[i] ^= (((row_num - i) * 37 + 178) & 0xFF) << 8;
	seed[i] ^= (((row_num - i) * 173 + 105) & 0xFF);
	}

	assert(stride % (BLOCK_SIZE * sizeof(pixel)) == 0);

	int offsets[2 /* col offset /][2 / row offset */];

	// process this row in BLOCK_SIZE^2 blocks
	for (unsigned bx = 0; bx < pw; bx += BLOCK_SIZE) {
	const int bw = imin(BLOCK_SIZE, (int) pw - bx);

	if (data->overlap_flag && bx) {
	// shift previous offsets left
	for (int i = 0; i < rows; i++)
	offsets[1][i] = offsets[0][i];
	}

	// update current offsets
	for (int i = 0; i < rows; i++)
	offsets[0][i] = get_random_number(8, &seed[i]);

	// x/y block offsets to compensate for overlapped regions
	const int ystart = data->overlap_flag && row_num ? imin(2, bh) : 0;
	const int xstart = data->overlap_flag && bx ? imin(2, bw) : 0;

	static const int w[2][2] = { { 27, 17 }, { 17, 27 } };

	#define add_noise_y(x, y, grain) \
	const pixel const src = src_row + (y) PXSTRIDE(stride) + (x) + bx; \
	pixel const dst = dst_row + (y) PXSTRIDE(stride) + (x) + bx; \
	const int noise = round2(scaling[ src ] (grain), data->scaling_shift); \
	dst = iclip(src + noise, min_value, max_value);

	for (int y = ystart; y < bh; y++) {
	// Non-overlapped image region (straightforward)
	for (int x = xstart; x < bw; x++) {
	int grain = sample_lut(grain_lut, offsets, 0, 0, 0, 0, x, y);
	add_noise_y(x, y, grain);
	}

	// Special case for overlapped column
	for (int x = 0; x < xstart; x++) {
	int grain = sample_lut(grain_lut, offsets, 0, 0, 0, 0, x, y);
	int old = sample_lut(grain_lut, offsets, 0, 0, 1, 0, x, y);
	grain = round2(old * w[x][0] + grain * w[x][1], 5);
	grain = iclip(grain, grain_min, grain_max);
	add_noise_y(x, y, grain);
	}
	}

	for (int y = 0; y < ystart; y++) {
	// Special case for overlapped row (sans corner)
	for (int x = xstart; x < bw; x++) {
	int grain = sample_lut(grain_lut, offsets, 0, 0, 0, 0, x, y);
	int old = sample_lut(grain_lut, offsets, 0, 0, 0, 1, x, y);
	grain = round2(old * w[y][0] + grain * w[y][1], 5);
	grain = iclip(grain, grain_min, grain_max);
	add_noise_y(x, y, grain);
	}

	// Special case for doubly-overlapped corner
	for (int x = 0; x < xstart; x++) {
	// Blend the top pixel with the top left block
	int top = sample_lut(grain_lut, offsets, 0, 0, 0, 1, x, y);
	int old = sample_lut(grain_lut, offsets, 0, 0, 1, 1, x, y);
	top = round2(old * w[x][0] + top * w[x][1], 5);
	top = iclip(top, grain_min, grain_max);

	// Blend the current pixel with the left block
	int grain = sample_lut(grain_lut, offsets, 0, 0, 0, 0, x, y);
	old = sample_lut(grain_lut, offsets, 0, 0, 1, 0, x, y);
	grain = round2(old * w[x][0] + grain * w[x][1], 5);
	grain = iclip(grain, grain_min, grain_max);

	// Mix the row rows together and apply grain
	grain = round2(top * w[y][0] + grain * w[y][1], 5);
	grain = iclip(grain, grain_min, grain_max);
	add_noise_y(x, y, grain);
	}
	}
	}
	}

	static NOINLINE void
	fguv_32x32xn_c(pixel const dst_row, const pixel const src_row,
	const ptrdiff_t stride, const Dav1dFilmGrainData *const data,
	const size_t pw, const uint8_t scaling[SCALING_SIZE],
	const entry grain_lut[][GRAIN_WIDTH], const int bh,
	const int row_num, const pixel *const luma_row,
	const ptrdiff_t luma_stride, const int uv, const int is_id,
	const int sx, const int sy HIGHBD_DECL_SUFFIX)
	{
	const int rows = 1 + (data->overlap_flag && row_num > 0);
	const int bitdepth_min_8 = bitdepth_from_max(bitdepth_max) - 8;
	const int grain_ctr = 128 << bitdepth_min_8;
	const int grain_min = -grain_ctr, grain_max = grain_ctr - 1;

	int min_value, max_value;
	if (data->clip_to_restricted_range) {
	min_value = 16 << bitdepth_min_8;
	max_value = (is_id ? 235 : 240) << bitdepth_min_8;
	} else {
	min_value = 0;
	max_value = BITDEPTH_MAX;
	}

	// seed[0] contains the current row, seed[1] contains the previous
	unsigned seed[2];
	for (int i = 0; i < rows; i++) {
	seed[i] = data->seed;
	seed[i] ^= (((row_num - i) * 37 + 178) & 0xFF) << 8;
	seed[i] ^= (((row_num - i) * 173 + 105) & 0xFF);
	}

	assert(stride % (BLOCK_SIZE * sizeof(pixel)) == 0);

	int offsets[2 /* col offset /][2 / row offset */];

	// process this row in BLOCK_SIZE^2 blocks (subsampled)
	for (unsigned bx = 0; bx < pw; bx += BLOCK_SIZE >> sx) {
	const int bw = imin(BLOCK_SIZE >> sx, (int)(pw - bx));
	if (data->overlap_flag && bx) {
	// shift previous offsets left
	for (int i = 0; i < rows; i++)
	offsets[1][i] = offsets[0][i];
	}

	// update current offsets
	for (int i = 0; i < rows; i++)
	offsets[0][i] = get_random_number(8, &seed[i]);

	// x/y block offsets to compensate for overlapped regions
	const int ystart = data->overlap_flag && row_num ? imin(2 >> sy, bh) : 0;
	const int xstart = data->overlap_flag && bx ? imin(2 >> sx, bw) : 0;

	static const int w[2 /* sub /][2 / off */][2] = {
	{ { 27, 17 }, { 17, 27 } },
	{ { 23, 22 } },
	};

	#define add_noise_uv(x, y, grain) \
	const int lx = (bx + x) << sx; \
	const int ly = y << sy; \
	const pixel const luma = luma_row + ly PXSTRIDE(luma_stride) + lx; \
	pixel avg = luma[0]; \
	if (sx) \
	avg = (avg + luma[1] + 1) >> 1; \
	const pixel const src = src_row + (y) PXSTRIDE(stride) + (bx + (x)); \
	pixel const dst = dst_row + (y) PXSTRIDE(stride) + (bx + (x)); \
	int val = avg; \
	if (!data->chroma_scaling_from_luma) { \
	const int combined = avg * data->uv_luma_mult[uv] + \
	src data->uv_mult[uv]; \
	val = iclip_pixel( (combined >> 6) + \
	(data->uv_offset[uv] * (1 << bitdepth_min_8)) ); \
	} \
	const int noise = round2(scaling[ val ] * (grain), data->scaling_shift); \
	dst = iclip(src + noise, min_value, max_value);

	for (int y = ystart; y < bh; y++) {
	// Non-overlapped image region (straightforward)
	for (int x = xstart; x < bw; x++) {
	int grain = sample_lut(grain_lut, offsets, sx, sy, 0, 0, x, y);
	add_noise_uv(x, y, grain);
	}

	// Special case for overlapped column
	for (int x = 0; x < xstart; x++) {
	int grain = sample_lut(grain_lut, offsets, sx, sy, 0, 0, x, y);
	int old = sample_lut(grain_lut, offsets, sx, sy, 1, 0, x, y);
	grain = round2(old * w[sx][x][0] + grain * w[sx][x][1], 5);
	grain = iclip(grain, grain_min, grain_max);
	add_noise_uv(x, y, grain);
	}
	}

	for (int y = 0; y < ystart; y++) {
	// Special case for overlapped row (sans corner)
	for (int x = xstart; x < bw; x++) {
	int grain = sample_lut(grain_lut, offsets, sx, sy, 0, 0, x, y);
	int old = sample_lut(grain_lut, offsets, sx, sy, 0, 1, x, y);
	grain = round2(old * w[sy][y][0] + grain * w[sy][y][1], 5);
	grain = iclip(grain, grain_min, grain_max);
	add_noise_uv(x, y, grain);
	}

	// Special case for doubly-overlapped corner
	for (int x = 0; x < xstart; x++) {
	// Blend the top pixel with the top left block
	int top = sample_lut(grain_lut, offsets, sx, sy, 0, 1, x, y);
	int old = sample_lut(grain_lut, offsets, sx, sy, 1, 1, x, y);
	top = round2(old * w[sx][x][0] + top * w[sx][x][1], 5);
	top = iclip(top, grain_min, grain_max);

	// Blend the current pixel with the left block
	int grain = sample_lut(grain_lut, offsets, sx, sy, 0, 0, x, y);
	old = sample_lut(grain_lut, offsets, sx, sy, 1, 0, x, y);
	grain = round2(old * w[sx][x][0] + grain * w[sx][x][1], 5);
	grain = iclip(grain, grain_min, grain_max);

	// Mix the row rows together and apply to image
	grain = round2(top * w[sy][y][0] + grain * w[sy][y][1], 5);
	grain = iclip(grain, grain_min, grain_max);
	add_noise_uv(x, y, grain);
	}
	}
	}
	}

	#define fguv_ss_fn(nm, ss_x, ss_y) \
	static decl_fguv_32x32xn_fn(fguv_32x32xn_##nm##_c) { \
	fguv_32x32xn_c(dst_row, src_row, stride, data, pw, scaling, grain_lut, bh, \
	row_num, luma_row, luma_stride, uv_pl, is_id, ss_x, ss_y \
	HIGHBD_TAIL_SUFFIX); \
	}

	fguv_ss_fn(420, 1, 1);
	fguv_ss_fn(422, 1, 0);
	fguv_ss_fn(444, 0, 0);

	#if HAVE_ASM
	#if ARCH_AARCH64 \|\| ARCH_ARM
	#include "src/arm/filmgrain.h"
	#elif ARCH_X86
	#include "src/x86/filmgrain.h"
	#endif
	#endif

	COLD void bitfn(dav1d_film_grain_dsp_init)(Dav1dFilmGrainDSPContext *const c) {
	c->generate_grain_y = generate_grain_y_c;
	c->generate_grain_uv[DAV1D_PIXEL_LAYOUT_I420 - 1] = generate_grain_uv_420_c;
	c->generate_grain_uv[DAV1D_PIXEL_LAYOUT_I422 - 1] = generate_grain_uv_422_c;
	c->generate_grain_uv[DAV1D_PIXEL_LAYOUT_I444 - 1] = generate_grain_uv_444_c;

	c->fgy_32x32xn = fgy_32x32xn_c;
	c->fguv_32x32xn[DAV1D_PIXEL_LAYOUT_I420 - 1] = fguv_32x32xn_420_c;
	c->fguv_32x32xn[DAV1D_PIXEL_LAYOUT_I422 - 1] = fguv_32x32xn_422_c;
	c->fguv_32x32xn[DAV1D_PIXEL_LAYOUT_I444 - 1] = fguv_32x32xn_444_c;

	#if HAVE_ASM
	#if ARCH_AARCH64 \|\| ARCH_ARM
	film_grain_dsp_init_arm(c);
	#elif ARCH_X86
	film_grain_dsp_init_x86(c);
	#endif
	#endif
	}