granicus.if.org Git - libvpx/blob - vp8/encoder/denoising.c

   1 /*
   2  *  Copyright (c) 2012 The WebM project authors. All Rights Reserved.
   3  *
   4  *  Use of this source code is governed by a BSD-style license
   5  *  that can be found in the LICENSE file in the root of the source
   6  *  tree. An additional intellectual property rights grant can be found
   7  *  in the file PATENTS.  All contributing project authors may
   8  *  be found in the AUTHORS file in the root of the source tree.
   9  */
  10
  11 #include <limits.h>
  12
  13 #include "denoising.h"
  14
  15 #include "vp8/common/reconinter.h"
  16 #include "vpx/vpx_integer.h"
  17 #include "vpx_mem/vpx_mem.h"
  18 #include "vp8_rtcd.h"
  19
  20 static const unsigned int NOISE_MOTION_THRESHOLD = 25 * 25;
  21 /* SSE_DIFF_THRESHOLD is selected as ~95% confidence assuming
  22  * var(noise) ~= 100.
  23  */
  24 static const unsigned int SSE_DIFF_THRESHOLD = 16 * 16 * 20;
  25 static const unsigned int SSE_THRESHOLD = 16 * 16 * 40;
  26 static const unsigned int SSE_THRESHOLD_HIGH = 16 * 16 * 60;
  27
  28 /*
  29  * The filter function was modified to reduce the computational complexity.
  30  * Step 1:
  31  * Instead of applying tap coefficients for each pixel, we calculated the
  32  * pixel adjustments vs. pixel diff value ahead of time.
  33  *     adjustment = filtered_value - current_raw
  34  *                = (filter_coefficient * diff + 128) >> 8
  35  * where
  36  *     filter_coefficient = (255 << 8) / (256 + ((absdiff * 330) >> 3));
  37  *     filter_coefficient += filter_coefficient /
  38  *                           (3 + motion_magnitude_adjustment);
  39  *     filter_coefficient is clamped to 0 ~ 255.
  40  *
  41  * Step 2:
  42  * The adjustment vs. diff curve becomes flat very quick when diff increases.
  43  * This allowed us to use only several levels to approximate the curve without
  44  * changing the filtering algorithm too much.
  45  * The adjustments were further corrected by checking the motion magnitude.
  46  * The levels used are:
  47  * diff       adjustment w/o motion correction   adjustment w/ motion correction
  48  * [-255, -16]           -6                                   -7
  49  * [-15, -8]             -4                                   -5
  50  * [-7, -4]              -3                                   -4
  51  * [-3, 3]               diff                                 diff
  52  * [4, 7]                 3                                    4
  53  * [8, 15]                4                                    5
  54  * [16, 255]              6                                    7
  55  */
  56
  57 int vp8_denoiser_filter_c(unsigned char *mc_running_avg_y, int mc_avg_y_stride,
  58                           unsigned char *running_avg_y, int avg_y_stride,
  59                           unsigned char *sig, int sig_stride,
  60                           unsigned int motion_magnitude,
  61                           int increase_denoising)
  62 {
  63     unsigned char *running_avg_y_start = running_avg_y;
  64     unsigned char *sig_start = sig;
  65     int sum_diff_thresh;
  66     int r, c;
  67     int sum_diff = 0;
  68     int adj_val[3] = {3, 4, 6};
  69     int shift_inc1 = 0;
  70     int shift_inc2 = 1;
  71     /* If motion_magnitude is small, making the denoiser more aggressive by
  72      * increasing the adjustment for each level. Add another increment for
  73      * blocks that are labeled for increase denoising. */
  74     if (motion_magnitude <= MOTION_MAGNITUDE_THRESHOLD)
  75     {
  76       if (increase_denoising) {
  77         shift_inc1 = 1;
  78         shift_inc2 = 2;
  79       }
  80       adj_val[0] += shift_inc2;
  81       adj_val[1] += shift_inc2;
  82       adj_val[2] += shift_inc2;
  83     }
  84
  85     for (r = 0; r < 16; ++r)
  86     {
  87         for (c = 0; c < 16; ++c)
  88         {
  89             int diff = 0;
  90             int adjustment = 0;
  91             int absdiff = 0;
  92
  93             diff = mc_running_avg_y[c] - sig[c];
  94             absdiff = abs(diff);
  95
  96             // When |diff| <= |3 + shift_inc1|, use pixel value from
  97             // last denoised raw.
  98             if (absdiff <= 3 + shift_inc1)
  99             {
 100                 running_avg_y[c] = mc_running_avg_y[c];
 101                 sum_diff += diff;
 102             }
 103             else
 104             {
 105                 if (absdiff >= 4 && absdiff <= 7)
 106                     adjustment = adj_val[0];
 107                 else if (absdiff >= 8 && absdiff <= 15)
 108                     adjustment = adj_val[1];
 109                 else
 110                     adjustment = adj_val[2];
 111
 112                 if (diff > 0)
 113                 {
 114                     if ((sig[c] + adjustment) > 255)
 115                         running_avg_y[c] = 255;
 116                     else
 117                         running_avg_y[c] = sig[c] + adjustment;
 118
 119                     sum_diff += adjustment;
 120                 }
 121                 else
 122                 {
 123                     if ((sig[c] - adjustment) < 0)
 124                         running_avg_y[c] = 0;
 125                     else
 126                         running_avg_y[c] = sig[c] - adjustment;
 127
 128                     sum_diff -= adjustment;
 129                 }
 130             }
 131         }
 132
 133         /* Update pointers for next iteration. */
 134         sig += sig_stride;
 135         mc_running_avg_y += mc_avg_y_stride;
 136         running_avg_y += avg_y_stride;
 137     }
 138
 139     sum_diff_thresh= SUM_DIFF_THRESHOLD;
 140     if (increase_denoising) sum_diff_thresh = SUM_DIFF_THRESHOLD_HIGH;
 141     if (abs(sum_diff) > sum_diff_thresh) {
 142       // Before returning to copy the block (i.e., apply no denoising), check
 143       // if we can still apply some (weaker) temporal filtering to this block,
 144       // that would otherwise not be denoised at all. Simplest is to apply
 145       // an additional adjustment to running_avg_y to bring it closer to sig.
 146       // The adjustment is capped by a maximum delta, and chosen such that
 147       // in most cases the resulting sum_diff will be within the
 148       // accceptable range given by sum_diff_thresh.
 149
 150       // The delta is set by the excess of absolute pixel diff over threshold.
 151       int delta = ((abs(sum_diff) - sum_diff_thresh) >> 8) + 1;
 152       // Only apply the adjustment for max delta up to 3.
 153       if (delta < 4) {
 154         sig -= sig_stride * 16;
 155         mc_running_avg_y -= mc_avg_y_stride * 16;
 156         running_avg_y -= avg_y_stride * 16;
 157         for (r = 0; r < 16; ++r) {
 158           for (c = 0; c < 16; ++c) {
 159             int diff = mc_running_avg_y[c] - sig[c];
 160             int adjustment = abs(diff);
 161             if (adjustment > delta)
 162               adjustment = delta;
 163             if (diff > 0) {
 164               // Bring denoised signal down.
 165               if (running_avg_y[c] - adjustment < 0)
 166                 running_avg_y[c] = 0;
 167               else
 168                 running_avg_y[c] = running_avg_y[c] - adjustment;
 169               sum_diff -= adjustment;
 170             } else if (diff < 0) {
 171               // Bring denoised signal up.
 172               if (running_avg_y[c] + adjustment > 255)
 173                 running_avg_y[c] = 255;
 174               else
 175                 running_avg_y[c] = running_avg_y[c] + adjustment;
 176               sum_diff += adjustment;
 177             }
 178           }
 179           // TODO(marpan): Check here if abs(sum_diff) has gone below the
 180           // threshold sum_diff_thresh, and if so, we can exit the row loop.
 181           sig += sig_stride;
 182           mc_running_avg_y += mc_avg_y_stride;
 183           running_avg_y += avg_y_stride;
 184         }
 185         if (abs(sum_diff) > sum_diff_thresh)
 186           return COPY_BLOCK;
 187       } else {
 188         return COPY_BLOCK;
 189       }
 190     }
 191
 192     vp8_copy_mem16x16(running_avg_y_start, avg_y_stride, sig_start, sig_stride);
 193     return FILTER_BLOCK;
 194 }
 195
 196 int vp8_denoiser_filter_uv_c(unsigned char *mc_running_avg_uv,
 197                              int mc_avg_uv_stride,
 198                              unsigned char *running_avg_uv,
 199                              int avg_uv_stride,
 200                              unsigned char *sig,
 201                              int sig_stride,
 202                              unsigned int motion_magnitude,
 203                              int increase_denoising) {
 204     unsigned char *running_avg_uv_start = running_avg_uv;
 205     unsigned char *sig_start = sig;
 206     int sum_diff_thresh;
 207     int r, c;
 208     int sum_diff = 0;
 209     int sum_block = 0;
 210     int adj_val[3] = {3, 4, 6};
 211     int shift_inc1 = 0;
 212     int shift_inc2 = 1;
 213     /* If motion_magnitude is small, making the denoiser more aggressive by
 214      * increasing the adjustment for each level. Add another increment for
 215      * blocks that are labeled for increase denoising. */
 216     if (motion_magnitude <= MOTION_MAGNITUDE_THRESHOLD_UV) {
 217       if (increase_denoising) {
 218         shift_inc1 = 1;
 219         shift_inc2 = 2;
 220       }
 221       adj_val[0] += shift_inc2;
 222       adj_val[1] += shift_inc2;
 223       adj_val[2] += shift_inc2;
 224     }
 225
 226     // Avoid denoising color signal if its close to average level.
 227     for (r = 0; r < 8; ++r) {
 228       for (c = 0; c < 8; ++c) {
 229         sum_block += sig[c];
 230       }
 231       sig += sig_stride;
 232     }
 233     if (abs(sum_block - (128 * 8 * 8)) < SUM_DIFF_FROM_AVG_THRESH_UV) {
 234       return COPY_BLOCK;
 235     }
 236
 237     sig -= sig_stride * 8;
 238     for (r = 0; r < 8; ++r) {
 239       for (c = 0; c < 8; ++c) {
 240         int diff = 0;
 241         int adjustment = 0;
 242         int absdiff = 0;
 243
 244         diff = mc_running_avg_uv[c] - sig[c];
 245         absdiff = abs(diff);
 246
 247         // When |diff| <= |3 + shift_inc1|, use pixel value from
 248         // last denoised raw.
 249         if (absdiff <= 3 + shift_inc1) {
 250           running_avg_uv[c] = mc_running_avg_uv[c];
 251           sum_diff += diff;
 252         } else {
 253           if (absdiff >= 4 && absdiff <= 7)
 254             adjustment = adj_val[0];
 255           else if (absdiff >= 8 && absdiff <= 15)
 256             adjustment = adj_val[1];
 257           else
 258             adjustment = adj_val[2];
 259           if (diff > 0) {
 260             if ((sig[c] + adjustment) > 255)
 261               running_avg_uv[c] = 255;
 262             else
 263               running_avg_uv[c] = sig[c] + adjustment;
 264             sum_diff += adjustment;
 265           } else {
 266             if ((sig[c] - adjustment) < 0)
 267               running_avg_uv[c] = 0;
 268             else
 269               running_avg_uv[c] = sig[c] - adjustment;
 270             sum_diff -= adjustment;
 271           }
 272         }
 273       }
 274       /* Update pointers for next iteration. */
 275       sig += sig_stride;
 276       mc_running_avg_uv += mc_avg_uv_stride;
 277       running_avg_uv += avg_uv_stride;
 278     }
 279
 280     sum_diff_thresh= SUM_DIFF_THRESHOLD_UV;
 281     if (increase_denoising) sum_diff_thresh = SUM_DIFF_THRESHOLD_HIGH_UV;
 282     if (abs(sum_diff) > sum_diff_thresh) {
 283       // Before returning to copy the block (i.e., apply no denoising), check
 284       // if we can still apply some (weaker) temporal filtering to this block,
 285       // that would otherwise not be denoised at all. Simplest is to apply
 286       // an additional adjustment to running_avg_y to bring it closer to sig.
 287       // The adjustment is capped by a maximum delta, and chosen such that
 288       // in most cases the resulting sum_diff will be within the
 289       // accceptable range given by sum_diff_thresh.
 290
 291       // The delta is set by the excess of absolute pixel diff over threshold.
 292       int delta = ((abs(sum_diff) - sum_diff_thresh) >> 8) + 1;
 293       // Only apply the adjustment for max delta up to 3.
 294       if (delta < 4) {
 295         sig -= sig_stride * 8;
 296         mc_running_avg_uv -= mc_avg_uv_stride * 8;
 297         running_avg_uv -= avg_uv_stride * 8;
 298         for (r = 0; r < 8; ++r) {
 299           for (c = 0; c < 8; ++c) {
 300             int diff = mc_running_avg_uv[c] - sig[c];
 301             int adjustment = abs(diff);
 302             if (adjustment > delta)
 303               adjustment = delta;
 304             if (diff > 0) {
 305               // Bring denoised signal down.
 306               if (running_avg_uv[c] - adjustment < 0)
 307                 running_avg_uv[c] = 0;
 308               else
 309                 running_avg_uv[c] = running_avg_uv[c] - adjustment;
 310               sum_diff -= adjustment;
 311             } else if (diff < 0) {
 312               // Bring denoised signal up.
 313               if (running_avg_uv[c] + adjustment > 255)
 314                 running_avg_uv[c] = 255;
 315               else
 316                 running_avg_uv[c] = running_avg_uv[c] + adjustment;
 317               sum_diff += adjustment;
 318             }
 319           }
 320           // TODO(marpan): Check here if abs(sum_diff) has gone below the
 321           // threshold sum_diff_thresh, and if so, we can exit the row loop.
 322           sig += sig_stride;
 323           mc_running_avg_uv += mc_avg_uv_stride;
 324           running_avg_uv += avg_uv_stride;
 325         }
 326         if (abs(sum_diff) > sum_diff_thresh)
 327           return COPY_BLOCK;
 328       } else {
 329         return COPY_BLOCK;
 330       }
 331     }
 332
 333     vp8_copy_mem8x8(running_avg_uv_start, avg_uv_stride, sig_start,
 334                     sig_stride);
 335     return FILTER_BLOCK;
 336 }
 337
 338 void vp8_denoiser_set_parameters(VP8_DENOISER *denoiser) {
 339   if (!denoiser->aggressive_mode) {
 340     denoiser->denoise_pars.scale_sse_thresh = 1;
 341     denoiser->denoise_pars.scale_motion_thresh = 8;
 342     denoiser->denoise_pars.scale_increase_filter = 0;
 343     denoiser->denoise_pars.denoise_mv_bias = 95;
 344     denoiser->denoise_pars.pickmode_mv_bias = 100;
 345     denoiser->denoise_pars.qp_thresh = 0;
 346     denoiser->denoise_pars.consec_zerolast = UINT_MAX;
 347   } else {
 348     denoiser->denoise_pars.scale_sse_thresh = 2;
 349     denoiser->denoise_pars.scale_motion_thresh = 16;
 350     denoiser->denoise_pars.scale_increase_filter = 1;
 351     denoiser->denoise_pars.denoise_mv_bias = 60;
 352     denoiser->denoise_pars.pickmode_mv_bias = 60;
 353     denoiser->denoise_pars.qp_thresh = 100;
 354     denoiser->denoise_pars.consec_zerolast = 10;
 355   }
 356 }
 357
 358 int vp8_denoiser_allocate(VP8_DENOISER *denoiser, int width, int height,
 359                           int num_mb_rows, int num_mb_cols, int mode)
 360 {
 361     int i;
 362     assert(denoiser);
 363     denoiser->num_mb_cols = num_mb_cols;
 364     denoiser->aggressive_mode = mode;
 365
 366     for (i = 0; i < MAX_REF_FRAMES; i++)
 367     {
 368         denoiser->yv12_running_avg[i].flags = 0;
 369
 370         if (vp8_yv12_alloc_frame_buffer(&(denoiser->yv12_running_avg[i]), width,
 371                                         height, VP8BORDERINPIXELS)
 372             < 0)
 373         {
 374             vp8_denoiser_free(denoiser);
 375             return 1;
 376         }
 377         vpx_memset(denoiser->yv12_running_avg[i].buffer_alloc, 0,
 378                    denoiser->yv12_running_avg[i].frame_size);
 379
 380     }
 381     denoiser->yv12_mc_running_avg.flags = 0;
 382
 383     if (vp8_yv12_alloc_frame_buffer(&(denoiser->yv12_mc_running_avg), width,
 384                                    height, VP8BORDERINPIXELS) < 0)
 385     {
 386         vp8_denoiser_free(denoiser);
 387         return 1;
 388     }
 389
 390     vpx_memset(denoiser->yv12_mc_running_avg.buffer_alloc, 0,
 391                denoiser->yv12_mc_running_avg.frame_size);
 392
 393     denoiser->denoise_state = vpx_calloc((num_mb_rows * num_mb_cols), 1);
 394     vpx_memset(denoiser->denoise_state, 0, (num_mb_rows * num_mb_cols));
 395     vp8_denoiser_set_parameters(denoiser);
 396     return 0;
 397 }
 398
 399
 400 void vp8_denoiser_free(VP8_DENOISER *denoiser)
 401 {
 402     int i;
 403     assert(denoiser);
 404
 405     for (i = 0; i < MAX_REF_FRAMES ; i++)
 406     {
 407         vp8_yv12_de_alloc_frame_buffer(&denoiser->yv12_running_avg[i]);
 408     }
 409     vp8_yv12_de_alloc_frame_buffer(&denoiser->yv12_mc_running_avg);
 410     vpx_free(denoiser->denoise_state);
 411 }
 412
 413
 414 void vp8_denoiser_denoise_mb(VP8_DENOISER *denoiser,
 415                              MACROBLOCK *x,
 416                              unsigned int best_sse,
 417                              unsigned int zero_mv_sse,
 418                              int recon_yoffset,
 419                              int recon_uvoffset,
 420                              loop_filter_info_n *lfi_n,
 421                              int mb_row,
 422                              int mb_col,
 423                              int block_index,
 424                              int uv_denoise)
 425 {
 426     int mv_row;
 427     int mv_col;
 428     unsigned int motion_threshold;
 429     unsigned int motion_magnitude2;
 430     unsigned int sse_thresh;
 431     int sse_diff_thresh = 0;
 432     // Spatial loop filter: only applied selectively based on
 433     // temporal filter state of block relative to top/left neighbors.
 434     int apply_spatial_loop_filter = 1;
 435     MV_REFERENCE_FRAME frame = x->best_reference_frame;
 436     MV_REFERENCE_FRAME zero_frame = x->best_zeromv_reference_frame;
 437
 438     enum vp8_denoiser_decision decision = FILTER_BLOCK;
 439     enum vp8_denoiser_decision decision_u = COPY_BLOCK;
 440     enum vp8_denoiser_decision decision_v = COPY_BLOCK;
 441
 442     if (zero_frame)
 443     {
 444         YV12_BUFFER_CONFIG *src = &denoiser->yv12_running_avg[frame];
 445         YV12_BUFFER_CONFIG *dst = &denoiser->yv12_mc_running_avg;
 446         YV12_BUFFER_CONFIG saved_pre,saved_dst;
 447         MB_MODE_INFO saved_mbmi;
 448         MACROBLOCKD *filter_xd = &x->e_mbd;
 449         MB_MODE_INFO *mbmi = &filter_xd->mode_info_context->mbmi;
 450         int sse_diff = 0;
 451         // Bias on zero motion vector sse.
 452         const int zero_bias = denoiser->denoise_pars.denoise_mv_bias;
 453         zero_mv_sse = (unsigned int)((int64_t)zero_mv_sse * zero_bias / 100);
 454         sse_diff = zero_mv_sse - best_sse;
 455
 456         saved_mbmi = *mbmi;
 457
 458         /* Use the best MV for the compensation. */
 459         mbmi->ref_frame = x->best_reference_frame;
 460         mbmi->mode = x->best_sse_inter_mode;
 461         mbmi->mv = x->best_sse_mv;
 462         mbmi->need_to_clamp_mvs = x->need_to_clamp_best_mvs;
 463         mv_col = x->best_sse_mv.as_mv.col;
 464         mv_row = x->best_sse_mv.as_mv.row;
 465         // Bias to zero_mv if small amount of motion.
 466         // Note sse_diff_thresh is intialized to zero, so this ensures
 467         // we will always choose zero_mv for denoising if
 468         // zero_mv_see <= best_sse (i.e., sse_diff <= 0).
 469         if ((unsigned int)(mv_row * mv_row + mv_col * mv_col)
 470             <= NOISE_MOTION_THRESHOLD)
 471             sse_diff_thresh = (int)SSE_DIFF_THRESHOLD;
 472
 473         if (frame == INTRA_FRAME ||
 474             sse_diff <= sse_diff_thresh)
 475         {
 476             /*
 477              * Handle intra blocks as referring to last frame with zero motion
 478              * and let the absolute pixel difference affect the filter factor.
 479              * Also consider small amount of motion as being random walk due
 480              * to noise, if it doesn't mean that we get a much bigger error.
 481              * Note that any changes to the mode info only affects the
 482              * denoising.
 483              */
 484             mbmi->ref_frame =
 485                     x->best_zeromv_reference_frame;
 486
 487             src = &denoiser->yv12_running_avg[zero_frame];
 488
 489             mbmi->mode = ZEROMV;
 490             mbmi->mv.as_int = 0;
 491             x->best_sse_inter_mode = ZEROMV;
 492             x->best_sse_mv.as_int = 0;
 493             best_sse = zero_mv_sse;
 494         }
 495
 496         saved_pre = filter_xd->pre;
 497         saved_dst = filter_xd->dst;
 498
 499         /* Compensate the running average. */
 500         filter_xd->pre.y_buffer = src->y_buffer + recon_yoffset;
 501         filter_xd->pre.u_buffer = src->u_buffer + recon_uvoffset;
 502         filter_xd->pre.v_buffer = src->v_buffer + recon_uvoffset;
 503         /* Write the compensated running average to the destination buffer. */
 504         filter_xd->dst.y_buffer = dst->y_buffer + recon_yoffset;
 505         filter_xd->dst.u_buffer = dst->u_buffer + recon_uvoffset;
 506         filter_xd->dst.v_buffer = dst->v_buffer + recon_uvoffset;
 507
 508         if (!x->skip)
 509         {
 510             vp8_build_inter_predictors_mb(filter_xd);
 511         }
 512         else
 513         {
 514             vp8_build_inter16x16_predictors_mb(filter_xd,
 515                                                filter_xd->dst.y_buffer,
 516                                                filter_xd->dst.u_buffer,
 517                                                filter_xd->dst.v_buffer,
 518                                                filter_xd->dst.y_stride,
 519                                                filter_xd->dst.uv_stride);
 520         }
 521         filter_xd->pre = saved_pre;
 522         filter_xd->dst = saved_dst;
 523         *mbmi = saved_mbmi;
 524
 525     }
 526
 527     mv_row = x->best_sse_mv.as_mv.row;
 528     mv_col = x->best_sse_mv.as_mv.col;
 529     motion_magnitude2 = mv_row * mv_row + mv_col * mv_col;
 530     motion_threshold = denoiser->denoise_pars.scale_motion_thresh *
 531         NOISE_MOTION_THRESHOLD;
 532
 533     if (motion_magnitude2 <
 534         denoiser->denoise_pars.scale_increase_filter * NOISE_MOTION_THRESHOLD)
 535       x->increase_denoising = 1;
 536
 537     sse_thresh = denoiser->denoise_pars.scale_sse_thresh * SSE_THRESHOLD;
 538     if (x->increase_denoising)
 539       sse_thresh = denoiser->denoise_pars.scale_sse_thresh * SSE_THRESHOLD_HIGH;
 540
 541     if (best_sse > sse_thresh || motion_magnitude2 > motion_threshold)
 542       decision = COPY_BLOCK;
 543
 544     if (decision == FILTER_BLOCK)
 545     {
 546         unsigned char *mc_running_avg_y =
 547             denoiser->yv12_mc_running_avg.y_buffer + recon_yoffset;
 548         int mc_avg_y_stride = denoiser->yv12_mc_running_avg.y_stride;
 549         unsigned char *running_avg_y =
 550             denoiser->yv12_running_avg[INTRA_FRAME].y_buffer + recon_yoffset;
 551         int avg_y_stride = denoiser->yv12_running_avg[INTRA_FRAME].y_stride;
 552
 553         /* Filter. */
 554         decision = vp8_denoiser_filter(mc_running_avg_y, mc_avg_y_stride,
 555                                        running_avg_y, avg_y_stride,
 556                                        x->thismb, 16, motion_magnitude2,
 557                                        x->increase_denoising);
 558         denoiser->denoise_state[block_index] = motion_magnitude2 > 0 ?
 559             kFilterNonZeroMV : kFilterZeroMV;
 560         // Only denoise UV for zero motion, and if y channel was denoised.
 561         if (uv_denoise &&
 562             motion_magnitude2 == 0 &&
 563             decision == FILTER_BLOCK) {
 564           unsigned char *mc_running_avg_u =
 565               denoiser->yv12_mc_running_avg.u_buffer + recon_uvoffset;
 566           unsigned char *running_avg_u =
 567               denoiser->yv12_running_avg[INTRA_FRAME].u_buffer + recon_uvoffset;
 568           unsigned char *mc_running_avg_v =
 569               denoiser->yv12_mc_running_avg.v_buffer + recon_uvoffset;
 570           unsigned char *running_avg_v =
 571               denoiser->yv12_running_avg[INTRA_FRAME].v_buffer + recon_uvoffset;
 572           int mc_avg_uv_stride = denoiser->yv12_mc_running_avg.uv_stride;
 573           int avg_uv_stride = denoiser->yv12_running_avg[INTRA_FRAME].uv_stride;
 574           int signal_stride = x->block[16].src_stride;
 575           decision_u =
 576               vp8_denoiser_filter_uv(mc_running_avg_u, mc_avg_uv_stride,
 577                                       running_avg_u, avg_uv_stride,
 578                                       x->block[16].src + *x->block[16].base_src,
 579                                       signal_stride, motion_magnitude2, 0);
 580           decision_v =
 581               vp8_denoiser_filter_uv(mc_running_avg_v, mc_avg_uv_stride,
 582                                       running_avg_v, avg_uv_stride,
 583                                       x->block[20].src + *x->block[20].base_src,
 584                                       signal_stride, motion_magnitude2, 0);
 585         }
 586     }
 587     if (decision == COPY_BLOCK)
 588     {
 589         /* No filtering of this block; it differs too much from the predictor,
 590          * or the motion vector magnitude is considered too big.
 591          */
 592         vp8_copy_mem16x16(
 593                 x->thismb, 16,
 594                 denoiser->yv12_running_avg[INTRA_FRAME].y_buffer + recon_yoffset,
 595                 denoiser->yv12_running_avg[INTRA_FRAME].y_stride);
 596         denoiser->denoise_state[block_index] = kNoFilter;
 597     }
 598     if (uv_denoise) {
 599       if (decision_u == COPY_BLOCK) {
 600         vp8_copy_mem8x8(
 601             x->block[16].src + *x->block[16].base_src, x->block[16].src_stride,
 602             denoiser->yv12_running_avg[INTRA_FRAME].u_buffer + recon_uvoffset,
 603             denoiser->yv12_running_avg[INTRA_FRAME].uv_stride);
 604       }
 605       if (decision_v == COPY_BLOCK) {
 606         vp8_copy_mem8x8(
 607             x->block[20].src + *x->block[20].base_src, x->block[16].src_stride,
 608             denoiser->yv12_running_avg[INTRA_FRAME].v_buffer + recon_uvoffset,
 609             denoiser->yv12_running_avg[INTRA_FRAME].uv_stride);
 610       }
 611     }
 612     // Option to selectively deblock the denoised signal, for y channel only.
 613     if (apply_spatial_loop_filter) {
 614       loop_filter_info lfi;
 615       int apply_filter_col = 0;
 616       int apply_filter_row = 0;
 617       int apply_filter = 0;
 618       int y_stride = denoiser->yv12_running_avg[INTRA_FRAME].y_stride;
 619       int uv_stride =denoiser->yv12_running_avg[INTRA_FRAME].uv_stride;
 620
 621       // Fix filter level to some nominal value for now.
 622       int filter_level = 32;
 623
 624       int hev_index = lfi_n->hev_thr_lut[INTER_FRAME][filter_level];
 625       lfi.mblim = lfi_n->mblim[filter_level];
 626       lfi.blim = lfi_n->blim[filter_level];
 627       lfi.lim = lfi_n->lim[filter_level];
 628       lfi.hev_thr = lfi_n->hev_thr[hev_index];
 629
 630       // Apply filter if there is a difference in the denoiser filter state
 631       // between the current and left/top block, or if non-zero motion vector
 632       // is used for the motion-compensated filtering.
 633       if (mb_col > 0) {
 634         apply_filter_col = !((denoiser->denoise_state[block_index] ==
 635             denoiser->denoise_state[block_index - 1]) &&
 636             denoiser->denoise_state[block_index] != kFilterNonZeroMV);
 637         if (apply_filter_col) {
 638           // Filter left vertical edge.
 639           apply_filter = 1;
 640           vp8_loop_filter_mbv(
 641               denoiser->yv12_running_avg[INTRA_FRAME].y_buffer + recon_yoffset,
 642               NULL, NULL, y_stride, uv_stride, &lfi);
 643         }
 644       }
 645       if (mb_row > 0) {
 646         apply_filter_row = !((denoiser->denoise_state[block_index] ==
 647             denoiser->denoise_state[block_index - denoiser->num_mb_cols]) &&
 648             denoiser->denoise_state[block_index] != kFilterNonZeroMV);
 649         if (apply_filter_row) {
 650           // Filter top horizontal edge.
 651           apply_filter = 1;
 652           vp8_loop_filter_mbh(
 653               denoiser->yv12_running_avg[INTRA_FRAME].y_buffer + recon_yoffset,
 654               NULL, NULL, y_stride, uv_stride, &lfi);
 655         }
 656       }
 657       if (apply_filter) {
 658         // Update the signal block |x|. Pixel changes are only to top and/or
 659         // left boundary pixels: can we avoid full block copy here.
 660         vp8_copy_mem16x16(
 661             denoiser->yv12_running_avg[INTRA_FRAME].y_buffer + recon_yoffset,
 662             y_stride, x->thismb, 16);
 663       }
 664     }
 665 }