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 "denoising.h"
  12
  13 #include "vp8/common/reconinter.h"
  14 #include "vpx/vpx_integer.h"
  15 #include "vpx_mem/vpx_mem.h"
  16 #include "vpx_rtcd.h"
  17
  18 const unsigned int NOISE_MOTION_THRESHOLD = 20*20;
  19 const unsigned int NOISE_DIFF2_THRESHOLD = 75;
  20 // SSE_DIFF_THRESHOLD is selected as ~95% confidence assuming var(noise) ~= 100.
  21 const unsigned int SSE_DIFF_THRESHOLD = 16*16*20;
  22 const unsigned int SSE_THRESHOLD = 16*16*40;
  23
  24 static uint8_t blend(uint8_t state, uint8_t sample, uint8_t factor_q8)
  25 {
  26   return (uint8_t)(
  27       (((uint16_t)factor_q8 * ((uint16_t)state) +  // Q8
  28         (uint16_t)(256 - factor_q8) * ((uint16_t)sample)) + 128)  // Q8
  29       >> 8);
  30 }
  31
  32 static unsigned int denoiser_motion_compensate(YV12_BUFFER_CONFIG* src,
  33                                                YV12_BUFFER_CONFIG* dst,
  34                                                MACROBLOCK* x,
  35                                                unsigned int best_sse,
  36                                                unsigned int zero_mv_sse,
  37                                                int recon_yoffset,
  38                                                int recon_uvoffset)
  39 {
  40   MACROBLOCKD filter_xd = x->e_mbd;
  41   int mv_col;
  42   int mv_row;
  43   int sse_diff = zero_mv_sse - best_sse;
  44   // Compensate the running average.
  45   filter_xd.pre.y_buffer = src->y_buffer + recon_yoffset;
  46   filter_xd.pre.u_buffer = src->u_buffer + recon_uvoffset;
  47   filter_xd.pre.v_buffer = src->v_buffer + recon_uvoffset;
  48   // Write the compensated running average to the destination buffer.
  49   filter_xd.dst.y_buffer = dst->y_buffer + recon_yoffset;
  50   filter_xd.dst.u_buffer = dst->u_buffer + recon_uvoffset;
  51   filter_xd.dst.v_buffer = dst->v_buffer + recon_uvoffset;
  52   // Use the best MV for the compensation.
  53   filter_xd.mode_info_context->mbmi.ref_frame = LAST_FRAME;
  54   filter_xd.mode_info_context->mbmi.mode = filter_xd.best_sse_inter_mode;
  55   filter_xd.mode_info_context->mbmi.mv = filter_xd.best_sse_mv;
  56   filter_xd.mode_info_context->mbmi.need_to_clamp_mvs =
  57       filter_xd.need_to_clamp_best_mvs;
  58   mv_col = filter_xd.best_sse_mv.as_mv.col;
  59   mv_row = filter_xd.best_sse_mv.as_mv.row;
  60   if (filter_xd.mode_info_context->mbmi.mode <= B_PRED ||
  61       (mv_row*mv_row + mv_col*mv_col <= NOISE_MOTION_THRESHOLD &&
  62        sse_diff < SSE_DIFF_THRESHOLD))
  63   {
  64     // Handle intra blocks as referring to last frame with zero motion and
  65     // let the absolute pixel difference affect the filter factor.
  66     // Also consider small amount of motion as being random walk due to noise,
  67     // if it doesn't mean that we get a much bigger error.
  68     // Note that any changes to the mode info only affects the denoising.
  69     filter_xd.mode_info_context->mbmi.ref_frame = LAST_FRAME;
  70     filter_xd.mode_info_context->mbmi.mode = ZEROMV;
  71     filter_xd.mode_info_context->mbmi.mv.as_int = 0;
  72     x->e_mbd.best_sse_inter_mode = ZEROMV;
  73     x->e_mbd.best_sse_mv.as_int = 0;
  74     best_sse = zero_mv_sse;
  75   }
  76   if (!x->skip)
  77   {
  78     vp8_build_inter_predictors_mb(&filter_xd);
  79   }
  80   else
  81   {
  82     vp8_build_inter16x16_predictors_mb(&filter_xd,
  83                                        filter_xd.dst.y_buffer,
  84                                        filter_xd.dst.u_buffer,
  85                                        filter_xd.dst.v_buffer,
  86                                        filter_xd.dst.y_stride,
  87                                        filter_xd.dst.uv_stride);
  88   }
  89   return best_sse;
  90 }
  91
  92 static void denoiser_filter(YV12_BUFFER_CONFIG* mc_running_avg,
  93                             YV12_BUFFER_CONFIG* running_avg,
  94                             MACROBLOCK* signal,
  95                             unsigned int motion_magnitude2,
  96                             int y_offset,
  97                             int uv_offset)
  98 {
  99   unsigned char* sig = signal->thismb;
 100   int sig_stride = 16;
 101   unsigned char* mc_running_avg_y = mc_running_avg->y_buffer + y_offset;
 102   int mc_avg_y_stride = mc_running_avg->y_stride;
 103   unsigned char* running_avg_y = running_avg->y_buffer + y_offset;
 104   int avg_y_stride = running_avg->y_stride;
 105   int r, c;
 106   for (r = 0; r < 16; r++)
 107   {
 108     for (c = 0; c < 16; c++)
 109     {
 110       int diff;
 111       int absdiff = 0;
 112       unsigned int filter_coefficient;
 113       absdiff = sig[c] - mc_running_avg_y[c];
 114       absdiff = absdiff > 0 ? absdiff : -absdiff;
 115       assert(absdiff >= 0 && absdiff < 256);
 116       filter_coefficient = (255 << 8) / (256 + ((absdiff * 330) >> 3));
 117       // Allow some additional filtering of static blocks, or blocks with very
 118       // small motion vectors.
 119       filter_coefficient += filter_coefficient / (3 + (motion_magnitude2 >> 3));
 120       filter_coefficient = filter_coefficient > 255 ? 255 : filter_coefficient;
 121
 122       running_avg_y[c] = blend(mc_running_avg_y[c], sig[c], filter_coefficient);
 123       diff = sig[c] - running_avg_y[c];
 124
 125       if (diff * diff < NOISE_DIFF2_THRESHOLD)
 126       {
 127         // Replace with mean to suppress the noise.
 128         sig[c] = running_avg_y[c];
 129       }
 130       else
 131       {
 132         // Replace the filter state with the signal since the change in this
 133         // pixel isn't classified as noise.
 134         running_avg_y[c] = sig[c];
 135       }
 136     }
 137     sig += sig_stride;
 138     mc_running_avg_y += mc_avg_y_stride;
 139     running_avg_y += avg_y_stride;
 140   }
 141 }
 142
 143 int vp8_denoiser_allocate(VP8_DENOISER *denoiser, int width, int height)
 144 {
 145   assert(denoiser);
 146   denoiser->yv12_running_avg.flags = 0;
 147   if (vp8_yv12_alloc_frame_buffer(&(denoiser->yv12_running_avg), width,
 148                                   height, VP8BORDERINPIXELS) < 0)
 149   {
 150       vp8_denoiser_free(denoiser);
 151       return 1;
 152   }
 153   denoiser->yv12_mc_running_avg.flags = 0;
 154   if (vp8_yv12_alloc_frame_buffer(&(denoiser->yv12_mc_running_avg), width,
 155                                   height, VP8BORDERINPIXELS) < 0)
 156   {
 157       vp8_denoiser_free(denoiser);
 158       return 1;
 159   }
 160   vpx_memset(denoiser->yv12_running_avg.buffer_alloc, 0,
 161              denoiser->yv12_running_avg.frame_size);
 162   vpx_memset(denoiser->yv12_mc_running_avg.buffer_alloc, 0,
 163              denoiser->yv12_mc_running_avg.frame_size);
 164   return 0;
 165 }
 166
 167 void vp8_denoiser_free(VP8_DENOISER *denoiser)
 168 {
 169   assert(denoiser);
 170   vp8_yv12_de_alloc_frame_buffer(&denoiser->yv12_running_avg);
 171   vp8_yv12_de_alloc_frame_buffer(&denoiser->yv12_mc_running_avg);
 172 }
 173
 174 void vp8_denoiser_denoise_mb(VP8_DENOISER *denoiser,
 175                              MACROBLOCK *x,
 176                              unsigned int best_sse,
 177                              unsigned int zero_mv_sse,
 178                              int recon_yoffset,
 179                              int recon_uvoffset) {
 180   int mv_row;
 181   int mv_col;
 182   unsigned int motion_magnitude2;
 183   // Motion compensate the running average.
 184   best_sse = denoiser_motion_compensate(&denoiser->yv12_running_avg,
 185                                         &denoiser->yv12_mc_running_avg,
 186                                         x,
 187                                         best_sse,
 188                                         zero_mv_sse,
 189                                         recon_yoffset,
 190                                         recon_uvoffset);
 191
 192   mv_row = x->e_mbd.best_sse_mv.as_mv.row;
 193   mv_col = x->e_mbd.best_sse_mv.as_mv.col;
 194   motion_magnitude2 = mv_row*mv_row + mv_col*mv_col;
 195   if (best_sse > SSE_THRESHOLD ||
 196       motion_magnitude2 > 8 * NOISE_MOTION_THRESHOLD)
 197   {
 198     // No filtering of this block since it differs too much from the predictor,
 199     // or the motion vector magnitude is considered too big.
 200     vp8_copy_mem16x16(x->thismb, 16,
 201                       denoiser->yv12_running_avg.y_buffer + recon_yoffset,
 202                       denoiser->yv12_running_avg.y_stride);
 203     return;
 204   }
 205   // Filter.
 206   denoiser_filter(&denoiser->yv12_mc_running_avg,
 207                   &denoiser->yv12_running_avg,
 208                   x,
 209                   motion_magnitude2,
 210                   recon_yoffset,
 211                   recon_uvoffset);
 212 }