Merge "Various updates to vp8."

examples/vpx_temporal_svc_encoder.c

@@ -675,6 +675,9 @@ int main(int argc, char **argv) {
         die_codec(&codec, "Failed to set SVC");
     }
   }
+  if (strncmp(encoder->name, "vp8", 3) == 0) {
+    vpx_codec_control(&codec, VP8E_SET_SCREEN_CONTENT_MODE, 0);
+  }
   vpx_codec_control(&codec, VP8E_SET_STATIC_THRESHOLD, 1);
   vpx_codec_control(&codec, VP8E_SET_TOKEN_PARTITIONS, 1);
   // This controls the maximum target size of the key frame.
@@ -697,6 +700,9 @@ int main(int argc, char **argv) {
         cfg.ts_layer_id[frame_cnt % cfg.ts_periodicity];
     if (strncmp(encoder->name, "vp9", 3) == 0) {
       vpx_codec_control(&codec, VP9E_SET_SVC_LAYER_ID, &layer_id);
+    } else if (strncmp(encoder->name, "vp8", 3) == 0) {
+      vpx_codec_control(&codec, VP8E_SET_TEMPORAL_LAYER_ID,
+                        layer_id.temporal_layer_id);
     }
     flags = layer_flags[frame_cnt % flag_periodicity];
     frame_avail = vpx_img_read(&raw, infile);

test/error_resilience_test.cc

@@ -316,7 +316,205 @@ TEST_P(ErrorResilienceTestLarge, 2LayersDropEnhancement) {
   Reset();
 }
 
+class ErrorResilienceTestLargeCodecControls : public ::libvpx_test::EncoderTest,
+    public ::libvpx_test::CodecTestWithParam<libvpx_test::TestMode> {
+ protected:
+  ErrorResilienceTestLargeCodecControls()
+      : EncoderTest(GET_PARAM(0)),
+        encoding_mode_(GET_PARAM(1)) {
+    Reset();
+  }
+
+  virtual ~ErrorResilienceTestLargeCodecControls() {}
+
+  void Reset() {
+    last_pts_ = 0;
+    tot_frame_number_ = 0;
+    // For testing up to 3 layers.
+    for (int i = 0; i < 3; ++i) {
+      bits_total_[i] = 0;
+    }
+    duration_ = 0.0;
+  }
+
+  virtual void SetUp() {
+    InitializeConfig();
+    SetMode(encoding_mode_);
+  }
+
+  //
+  // Frame flags and layer id for temporal layers.
+  //
+
+  // For two layers, test pattern is:
+  //   1     3
+  // 0    2     .....
+  // For three layers, test pattern is:
+  //   1      3    5      7
+  //      2           6
+  // 0          4            ....
+  // LAST is always update on base/layer 0, GOLDEN is updated on layer 1,
+  // and ALTREF is updated on top layer for 3 layer pattern.
+  int SetFrameFlags(int frame_num, int num_temp_layers) {
+    int frame_flags = 0;
+    if (num_temp_layers == 2) {
+      if (frame_num % 2 == 0) {
+        // Layer 0: predict from L and ARF, update L.
+        frame_flags = VP8_EFLAG_NO_REF_GF | VP8_EFLAG_NO_UPD_GF |
+                      VP8_EFLAG_NO_UPD_ARF;
+      } else {
+        // Layer 1: predict from L, G and ARF, and update G.
+        frame_flags = VP8_EFLAG_NO_UPD_ARF | VP8_EFLAG_NO_UPD_LAST |
+                      VP8_EFLAG_NO_UPD_ENTROPY;
+      }
+    } else if (num_temp_layers == 3) {
+      if (frame_num % 4 == 0) {
+        // Layer 0: predict from L, update L.
+        frame_flags = VP8_EFLAG_NO_UPD_GF | VP8_EFLAG_NO_UPD_ARF |
+                      VP8_EFLAG_NO_REF_GF | VP8_EFLAG_NO_REF_ARF;
+      } else if ((frame_num - 2) % 4 == 0) {
+        // Layer 1: predict from L, G,  update G.
+        frame_flags = VP8_EFLAG_NO_UPD_ARF | VP8_EFLAG_NO_UPD_LAST |
+                      VP8_EFLAG_NO_REF_ARF;
+      }  else if ((frame_num - 1) % 2 == 0) {
+        // Layer 2: predict from L, G, ARF; update ARG.
+        frame_flags = VP8_EFLAG_NO_UPD_GF | VP8_EFLAG_NO_UPD_LAST;
+      }
+    }
+    return frame_flags;
+  }
+
+  int SetLayerId(int frame_num, int num_temp_layers) {
+    int layer_id = 0;
+    if (num_temp_layers == 2) {
+      if (frame_num % 2 == 0) {
+        layer_id = 0;
+      } else {
+         layer_id = 1;
+      }
+    } else if (num_temp_layers == 3) {
+      if (frame_num % 4 == 0) {
+        layer_id = 0;
+      } else if ((frame_num - 2) % 4 == 0) {
+        layer_id = 1;
+      } else if ((frame_num - 1) % 2 == 0) {
+        layer_id = 2;
+      }
+    }
+    return layer_id;
+  }
+
+  virtual void PreEncodeFrameHook(libvpx_test::VideoSource *video,
+                                  libvpx_test::Encoder *encoder) {
+    if (cfg_.ts_number_layers > 1) {
+        int layer_id = SetLayerId(video->frame(), cfg_.ts_number_layers);
+        int frame_flags = SetFrameFlags(video->frame(), cfg_.ts_number_layers);
+        if (video->frame() > 0) {
+          encoder->Control(VP8E_SET_TEMPORAL_LAYER_ID, layer_id);
+          encoder->Control(VP8E_SET_FRAME_FLAGS, frame_flags);
+        }
+       const vpx_rational_t tb = video->timebase();
+       timebase_ = static_cast<double>(tb.num) / tb.den;
+       duration_ = 0;
+       return;
+    }
+  }
+
+  virtual void FramePktHook(const vpx_codec_cx_pkt_t *pkt) {
+    // Time since last timestamp = duration.
+    vpx_codec_pts_t duration = pkt->data.frame.pts - last_pts_;
+    if (duration > 1) {
+      // Update counter for total number of frames (#frames input to encoder).
+      // Needed for setting the proper layer_id below.
+      tot_frame_number_ += static_cast<int>(duration - 1);
+    }
+    int layer = SetLayerId(tot_frame_number_, cfg_.ts_number_layers);
+    const size_t frame_size_in_bits = pkt->data.frame.sz * 8;
+    // Update the total encoded bits. For temporal layers, update the cumulative
+    // encoded bits per layer.
+    for (int i = layer; i < static_cast<int>(cfg_.ts_number_layers); ++i) {
+      bits_total_[i] += frame_size_in_bits;
+    }
+    // Update the most recent pts.
+    last_pts_ = pkt->data.frame.pts;
+    ++tot_frame_number_;
+  }
+
+  virtual void EndPassHook(void) {
+    duration_ = (last_pts_ + 1) * timebase_;
+    if (cfg_.ts_number_layers  > 1) {
+      for (int layer = 0; layer < static_cast<int>(cfg_.ts_number_layers);
+          ++layer) {
+        if (bits_total_[layer]) {
+          // Effective file datarate:
+          effective_datarate_[layer] = (bits_total_[layer] / 1000.0) / duration_;
+        }
+      }
+    }
+  }
+
+  double effective_datarate_[3];
+   private:
+    libvpx_test::TestMode encoding_mode_;
+    vpx_codec_pts_t last_pts_;
+    double timebase_;
+    int64_t bits_total_[3];
+    double duration_;
+    int tot_frame_number_;
+  };
+
+// Check two codec controls used for:
+// (1) for setting temporal layer id, and (2) for settings encoder flags.
+// This test invokes those controls for each frame, and verifies encoder/decoder
+// mismatch and basic rate control response.
+// TODO(marpan): Maybe move this test to datarate_test.cc.
+TEST_P(ErrorResilienceTestLargeCodecControls, CodecControl3TemporalLayers) {
+  cfg_.rc_buf_initial_sz = 500;
+  cfg_.rc_buf_optimal_sz = 500;
+  cfg_.rc_buf_sz = 1000;
+  cfg_.rc_dropframe_thresh = 1;
+  cfg_.rc_min_quantizer = 2;
+  cfg_.rc_max_quantizer = 56;
+  cfg_.rc_end_usage = VPX_CBR;
+  cfg_.rc_dropframe_thresh = 1;
+  cfg_.g_lag_in_frames = 0;
+  cfg_.kf_mode = VPX_KF_DISABLED;
+  cfg_.g_error_resilient = 1;
+
+  // 3 Temporal layers. Framerate decimation (4, 2, 1).
+  cfg_.ts_number_layers = 3;
+  cfg_.ts_rate_decimator[0] = 4;
+  cfg_.ts_rate_decimator[1] = 2;
+  cfg_.ts_rate_decimator[2] = 1;
+  cfg_.ts_periodicity = 4;
+  cfg_.ts_layer_id[0] = 0;
+  cfg_.ts_layer_id[1] = 2;
+  cfg_.ts_layer_id[2] = 1;
+  cfg_.ts_layer_id[3] = 2;
+
+  ::libvpx_test::I420VideoSource video("hantro_collage_w352h288.yuv", 352, 288,
+                                       30, 1, 0, 200);
+  for (int i = 200; i <= 800; i += 200) {
+    cfg_.rc_target_bitrate = i;
+    Reset();
+    // 40-20-40 bitrate allocation for 3 temporal layers.
+    cfg_.ts_target_bitrate[0] = 40 * cfg_.rc_target_bitrate / 100;
+    cfg_.ts_target_bitrate[1] = 60 * cfg_.rc_target_bitrate / 100;
+    cfg_.ts_target_bitrate[2] = cfg_.rc_target_bitrate;
+    ASSERT_NO_FATAL_FAILURE(RunLoop(&video));
+    for (int j = 0; j < static_cast<int>(cfg_.ts_number_layers); ++j) {
+      ASSERT_GE(effective_datarate_[j], cfg_.ts_target_bitrate[j] * 0.75)
+          << " The datarate for the file is lower than target by too much, "
+              "for layer: " << j;
+      ASSERT_LE(effective_datarate_[j], cfg_.ts_target_bitrate[j] * 1.25)
+          << " The datarate for the file is greater than target by too much, "
+              "for layer: " << j;
+    }
+  }
+}
+
 VP8_INSTANTIATE_TEST_CASE(ErrorResilienceTestLarge, ONE_PASS_TEST_MODES);
+VP8_INSTANTIATE_TEST_CASE(ErrorResilienceTestLargeCodecControls,
+                          ONE_PASS_TEST_MODES);
 VP9_INSTANTIATE_TEST_CASE(ErrorResilienceTestLarge, ONE_PASS_TEST_MODES);
-
 }  // namespace

vp8/common/blockd.h

@@ -187,8 +187,12 @@ typedef struct
 {
     FRAME_TYPE frame_type;
     int is_frame_dropped;
+    // The frame rate for the lowest resolution.
+    double low_res_framerate;
     /* The frame number of each reference frames */
     unsigned int low_res_ref_frames[MAX_REF_FRAMES];
+    // The video frame counter value for the key frame, for lowest resolution.
+    unsigned int key_frame_counter_value;
     LOWER_RES_MB_INFO *mb_info;
 } LOWER_RES_FRAME_INFO;
 #endif

vp8/common/onyx.h

@@ -122,6 +122,7 @@ extern "C"
         int Sharpness;
         int cpu_used;
         unsigned int rc_max_intra_bitrate_pct;
+        unsigned int screen_content_mode;
 
         /* mode ->
          *(0)=Realtime/Live Encoding. This mode is optimized for realtim

vp8/encoder/block.h

@@ -125,6 +125,8 @@ typedef struct macroblock
 
     int optimize;
     int q_index;
+    int is_skin;
+    int denoise_zeromv;
 
 #if CONFIG_TEMPORAL_DENOISING
     int increase_denoising;
@@ -161,6 +163,8 @@ typedef struct macroblock
     void (*short_walsh4x4)(short *input, short *output, int pitch);
     void (*quantize_b)(BLOCK *b, BLOCKD *d);
 
+    unsigned int mbs_zero_last_dot_suppress;
+    int zero_last_dot_suppress;
 } MACROBLOCK;
 
 

vp8/encoder/denoising.c

@@ -391,7 +391,7 @@ void vp8_denoiser_set_parameters(VP8_DENOISER *denoiser, int mode) {
     denoiser->denoise_pars.scale_increase_filter = 1;
     denoiser->denoise_pars.denoise_mv_bias = 60;
     denoiser->denoise_pars.pickmode_mv_bias = 75;
-    denoiser->denoise_pars.qp_thresh = 85;
+    denoiser->denoise_pars.qp_thresh = 80;
     denoiser->denoise_pars.consec_zerolast = 15;
     denoiser->denoise_pars.spatial_blur = 0;
   }
@@ -456,10 +456,10 @@ int vp8_denoiser_allocate(VP8_DENOISER *denoiser, int width, int height,
     denoiser->bitrate_threshold = 400000;  // (bits/sec).
     denoiser->threshold_aggressive_mode = 80;
     if (width * height > 1280 * 720) {
-      denoiser->bitrate_threshold = 2500000;
-      denoiser->threshold_aggressive_mode = 180;
+      denoiser->bitrate_threshold = 3000000;
+      denoiser->threshold_aggressive_mode = 200;
     } else if (width * height > 960 * 540) {
-      denoiser->bitrate_threshold = 1000000;
+      denoiser->bitrate_threshold = 1200000;
       denoiser->threshold_aggressive_mode = 120;
     } else if (width * height > 640 * 480) {
       denoiser->bitrate_threshold = 600000;
@@ -483,7 +483,6 @@ void vp8_denoiser_free(VP8_DENOISER *denoiser)
     vpx_free(denoiser->denoise_state);
 }
 
-
 void vp8_denoiser_denoise_mb(VP8_DENOISER *denoiser,
                              MACROBLOCK *x,
                              unsigned int best_sse,
@@ -554,6 +553,7 @@ void vp8_denoiser_denoise_mb(VP8_DENOISER *denoiser,
              * Note that any changes to the mode info only affects the
              * denoising.
              */
+            x->denoise_zeromv = 1;
             mbmi->ref_frame =
                     x->best_zeromv_reference_frame;
 
@@ -603,6 +603,12 @@ void vp8_denoiser_denoise_mb(VP8_DENOISER *denoiser,
     motion_threshold = denoiser->denoise_pars.scale_motion_thresh *
         NOISE_MOTION_THRESHOLD;
 
+    // If block is considered to be skin area, lower the motion threshold.
+    // In current version set threshold = 1, so only denoise very low
+    // (i.e., zero) mv on skin.
+    if (x->is_skin)
+        motion_threshold = 1;
+
     if (motion_magnitude2 <
         denoiser->denoise_pars.scale_increase_filter * NOISE_MOTION_THRESHOLD)
       x->increase_denoising = 1;
@@ -662,6 +668,7 @@ void vp8_denoiser_denoise_mb(VP8_DENOISER *denoiser,
         /* No filtering of this block; it differs too much from the predictor,
          * or the motion vector magnitude is considered too big.
          */
+        x->denoise_zeromv = 0;
         vp8_copy_mem16x16(
                 x->thismb, 16,
                 denoiser->yv12_running_avg[INTRA_FRAME].y_buffer + recon_yoffset,
@@ -692,7 +699,7 @@ void vp8_denoiser_denoise_mb(VP8_DENOISER *denoiser,
       int uv_stride =denoiser->yv12_running_avg[INTRA_FRAME].uv_stride;
 
       // Fix filter level to some nominal value for now.
-      int filter_level = 32;
+      int filter_level = 48;
 
       int hev_index = lfi_n->hev_thr_lut[INTER_FRAME][filter_level];
       lfi.mblim = lfi_n->mblim[filter_level];

vp8/encoder/denoising.h

@@ -19,7 +19,7 @@ extern "C" {
 #endif
 
 #define SUM_DIFF_THRESHOLD (16 * 16 * 2)
-#define SUM_DIFF_THRESHOLD_HIGH (600)
+#define SUM_DIFF_THRESHOLD_HIGH (600)  // ~(16 * 16 * 1.5)
 #define MOTION_MAGNITUDE_THRESHOLD (8*3)
 
 #define SUM_DIFF_THRESHOLD_UV (96)   // (8 * 8 * 1.5)
@@ -27,7 +27,7 @@ extern "C" {
 #define SUM_DIFF_FROM_AVG_THRESH_UV (8 * 8 * 8)
 #define MOTION_MAGNITUDE_THRESHOLD_UV (8*3)
 
-#define MAX_GF_ARF_DENOISE_RANGE (16)
+#define MAX_GF_ARF_DENOISE_RANGE (8)
 
 enum vp8_denoiser_decision
 {

vp8/encoder/encodeframe.c

@@ -522,7 +522,8 @@ void encode_mb_row(VP8_COMP *cpi,
             }
 
 #endif
-            // Keep track of how many (consecutive) times a block is coded
+
+            // Keep track of how many (consecutive) times a  block is coded
             // as ZEROMV_LASTREF, for base layer frames.
             // Reset to 0 if its coded as anything else.
             if (cpi->current_layer == 0) {
@@ -531,9 +532,14 @@ void encode_mb_row(VP8_COMP *cpi,
                 // Increment, check for wrap-around.
                 if (cpi->consec_zero_last[map_index+mb_col] < 255)
                   cpi->consec_zero_last[map_index+mb_col] += 1;
+                if (cpi->consec_zero_last_mvbias[map_index+mb_col] < 255)
+                  cpi->consec_zero_last_mvbias[map_index+mb_col] += 1;
               } else {
                 cpi->consec_zero_last[map_index+mb_col] = 0;
+                cpi->consec_zero_last_mvbias[map_index+mb_col] = 0;
               }
+              if (x->zero_last_dot_suppress)
+                cpi->consec_zero_last_mvbias[map_index+mb_col] = 0;
             }
 
             /* Special case code for cyclic refresh

vp8/encoder/ethreading.c

@@ -215,11 +215,15 @@ THREAD_FUNCTION thread_encoding_proc(void *p_data)
                                   LAST_FRAME) {
                             // Increment, check for wrap-around.
                             if (cpi->consec_zero_last[map_index+mb_col] < 255)
-                              cpi->consec_zero_last[map_index+mb_col] +=
-                                  1;
+                              cpi->consec_zero_last[map_index+mb_col] += 1;
+                            if (cpi->consec_zero_last_mvbias[map_index+mb_col] < 255)
+                              cpi->consec_zero_last_mvbias[map_index+mb_col] += 1;
                           } else {
                             cpi->consec_zero_last[map_index+mb_col] = 0;
+                            cpi->consec_zero_last_mvbias[map_index+mb_col] = 0;
                           }
+                          if (x->zero_last_dot_suppress)
+                            cpi->consec_zero_last_mvbias[map_index+mb_col] = 0;
                         }
 
                         /* Special case code for cyclic refresh
@@ -505,6 +509,7 @@ void vp8cx_init_mbrthread_data(VP8_COMP *cpi,
         mb->intra_error = 0;
         vp8_zero(mb->count_mb_ref_frame_usage);
         mb->mbs_tested_so_far = 0;
+        mb->mbs_zero_last_dot_suppress = 0;
     }
 }
 

vp8/encoder/onyx_int.h

@@ -513,10 +513,18 @@ typedef struct VP8_COMP
     signed char *cyclic_refresh_map;
     // Count on how many (consecutive) times a macroblock uses ZER0MV_LAST.
     unsigned char *consec_zero_last;
+    // Counter that is reset when a block is checked for a mode-bias against
+    // ZEROMV_LASTREF.
+    unsigned char *consec_zero_last_mvbias;
 
     // Frame counter for the temporal pattern. Counter is rest when the temporal
     // layers are changed dynamically (run-time change).
     unsigned int temporal_pattern_counter;
+    // Temporal layer id.
+    int temporal_layer_id;
+
+    // Measure of average squared difference between source and denoised signal.
+    int mse_source_denoised;
 
 #if CONFIG_MULTITHREAD
     /* multithread data */
@@ -687,6 +695,7 @@ typedef struct VP8_COMP
 #endif
     /* The frame number of each reference frames */
     unsigned int current_ref_frames[MAX_REF_FRAMES];
+    // Closest reference frame to current frame.
     MV_REFERENCE_FRAME closest_reference_frame;
 
     struct rd_costs_struct

vp8/encoder/pickinter.c

@@ -40,6 +40,134 @@ extern const MB_PREDICTION_MODE vp8_mode_order[MAX_MODES];
 
 extern int vp8_cost_mv_ref(MB_PREDICTION_MODE m, const int near_mv_ref_ct[4]);
 
+// Fixed point implementation of a skin color classifier. Skin color
+// is model by a Gaussian distribution in the CbCr color space.
+// See ../../test/skin_color_detector_test.cc where the reference
+// skin color classifier is defined.
+
+// Fixed-point skin color model parameters.
+static const int skin_mean[2] = {7463, 9614};                 // q6
+static const int skin_inv_cov[4] = {4107, 1663, 1663, 2157};  // q16
+static const int skin_threshold = 1570636;                    // q18
+
+// Evaluates the Mahalanobis distance measure for the input CbCr values.
+static int evaluate_skin_color_difference(int cb, int cr)
+{
+  const int cb_q6 = cb << 6;
+  const int cr_q6 = cr << 6;
+  const int cb_diff_q12 = (cb_q6 - skin_mean[0]) * (cb_q6 - skin_mean[0]);
+  const int cbcr_diff_q12 = (cb_q6 - skin_mean[0]) * (cr_q6 - skin_mean[1]);
+  const int cr_diff_q12 = (cr_q6 - skin_mean[1]) * (cr_q6 - skin_mean[1]);
+  const int cb_diff_q2 = (cb_diff_q12 + (1 << 9)) >> 10;
+  const int cbcr_diff_q2 = (cbcr_diff_q12 + (1 << 9)) >> 10;
+  const int cr_diff_q2 = (cr_diff_q12 + (1 << 9)) >> 10;
+  const int skin_diff = skin_inv_cov[0] * cb_diff_q2 +
+      skin_inv_cov[1] * cbcr_diff_q2 +
+      skin_inv_cov[2] * cbcr_diff_q2 +
+      skin_inv_cov[3] * cr_diff_q2;
+  return skin_diff;
+}
+
+static int macroblock_corner_grad(unsigned char* signal, int stride,
+                                  int offsetx, int offsety, int sgnx, int sgny)
+{
+  int y1 = signal[offsetx * stride + offsety];
+  int y2 = signal[offsetx * stride + offsety + sgny];
+  int y3 = signal[(offsetx + sgnx) * stride + offsety];
+  int y4 = signal[(offsetx + sgnx) * stride + offsety + sgny];
+  return MAX(MAX(abs(y1 - y2), abs(y1 - y3)), abs(y1 - y4));
+}
+
+static int check_dot_artifact_candidate(VP8_COMP *cpi,
+                                        MACROBLOCK *x,
+                                        unsigned char *target_last,
+                                        int stride,
+                                        unsigned char* last_ref,
+                                        int mb_row,
+                                        int mb_col,
+                                        int channel)
+{
+  int threshold1 = 6;
+  int threshold2 = 3;
+  unsigned int max_num = (cpi->common.MBs) / 10;
+  int grad_last = 0;
+  int grad_source = 0;
+  int index = mb_row * cpi->common.mb_cols + mb_col;
+  // Threshold for #consecutive (base layer) frames using zero_last mode.
+  int num_frames = 30;
+  int shift = 15;
+  if (channel > 0) {
+    shift = 7;
+  }
+  if (cpi->oxcf.number_of_layers > 1)
+  {
+    num_frames = 20;
+  }
+  x->zero_last_dot_suppress = 0;
+  // Blocks on base layer frames that have been using ZEROMV_LAST repeatedly
+  // (i.e, at least |x| consecutive frames are candidates for increasing the
+  // rd adjustment for zero_last mode.
+  // Only allow this for at most |max_num| blocks per frame.
+  // Don't allow this for screen content input.
+  if (cpi->current_layer == 0 &&
+      cpi->consec_zero_last_mvbias[index] > num_frames &&
+      x->mbs_zero_last_dot_suppress < max_num &&
+      !cpi->oxcf.screen_content_mode)
+  {
+    // If this block is checked here, label it so we don't check it again until
+    // ~|x| framaes later.
+    x->zero_last_dot_suppress = 1;
+    // Dot artifact is noticeable as strong gradient at corners of macroblock,
+    // for flat areas. As a simple detector for now, we look for a high
+    // corner gradient on last ref, and a smaller gradient on source.
+    // Check 4 corners, return if any satisfy condition.
+    // Top-left:
+    grad_last = macroblock_corner_grad(last_ref, stride, 0, 0, 1, 1);
+    grad_source = macroblock_corner_grad(target_last, stride, 0, 0, 1, 1);
+    if (grad_last >= threshold1 && grad_source <= threshold2)
+    {
+       x->mbs_zero_last_dot_suppress++;
+       return 1;
+    }
+    // Top-right:
+    grad_last = macroblock_corner_grad(last_ref, stride, 0, shift, 1, -1);
+    grad_source = macroblock_corner_grad(target_last, stride, 0, shift, 1, -1);
+    if (grad_last >= threshold1 && grad_source <= threshold2)
+    {
+      x->mbs_zero_last_dot_suppress++;
+      return 1;
+    }
+    // Bottom-left:
+    grad_last = macroblock_corner_grad(last_ref, stride, shift, 0, -1, 1);
+    grad_source = macroblock_corner_grad(target_last, stride, shift, 0, -1, 1);
+    if (grad_last >= threshold1 && grad_source <= threshold2)
+    {
+      x->mbs_zero_last_dot_suppress++;
+      return 1;
+    }
+    // Bottom-right:
+    grad_last = macroblock_corner_grad(last_ref, stride, shift, shift, -1, -1);
+    grad_source = macroblock_corner_grad(target_last, stride, shift, shift, -1, -1);
+    if (grad_last >= threshold1 && grad_source <= threshold2)
+    {
+      x->mbs_zero_last_dot_suppress++;
+      return 1;
+    }
+    return 0;
+  }
+  return 0;
+}
+
+// Checks if the input yCbCr values corresponds to skin color.
+static int is_skin_color(int y, int cb, int cr)
+{
+  if (y < 40 || y > 220)
+  {
+    return 0;
+  }
+  return (evaluate_skin_color_difference(cb, cr) < skin_threshold);
+}
+
 int vp8_skip_fractional_mv_step(MACROBLOCK *mb, BLOCK *b, BLOCKD *d,
                                 int_mv *bestmv, int_mv *ref_mv,
                                 int error_per_bit,
@@ -514,10 +642,17 @@ static int evaluate_inter_mode(unsigned int* sse, int rate2, int* distortion2,
 #endif
 
     // Adjust rd for ZEROMV and LAST, if LAST is the closest reference frame.
-    if (this_mode == ZEROMV &&
-        x->e_mbd.mode_info_context->mbmi.ref_frame == LAST_FRAME &&
-        (denoise_aggressive || cpi->closest_reference_frame == LAST_FRAME)) {
-      this_rd = ((int64_t)this_rd) * rd_adj / 100;
+    // TODO: We should also add condition on distance of closest to current.
+    if(!cpi->oxcf.screen_content_mode &&
+       this_mode == ZEROMV &&
+       x->e_mbd.mode_info_context->mbmi.ref_frame == LAST_FRAME &&
+       (denoise_aggressive || (cpi->closest_reference_frame == LAST_FRAME)))
+    {
+        // No adjustment if block is considered to be skin area.
+        if(x->is_skin)
+            rd_adj = 100;
+
+        this_rd = ((int64_t)this_rd) * rd_adj / 100;
     }
 
     check_for_encode_breakout(*sse, x);
@@ -597,6 +732,15 @@ void vp8_pick_inter_mode(VP8_COMP *cpi, MACROBLOCK *x, int recon_yoffset,
 #endif
 
     int sf_improved_mv_pred = cpi->sf.improved_mv_pred;
+
+#if CONFIG_MULTI_RES_ENCODING
+    int dissim = INT_MAX;
+    int parent_ref_frame = 0;
+    int_mv parent_ref_mv;
+    MB_PREDICTION_MODE parent_mode = 0;
+    int parent_ref_valid = 0;
+#endif
+