text: /*
   *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
   *
   *  Use of this source code is governed by a BSD-style license
   *  that can be found in the LICENSE file in the root of the source
   *  tree. An additional intellectual property rights grant can be found
   *  in the file PATENTS.  All contributing project authors may
   *  be found in the AUTHORS file in the root of the source tree.
   */
  
  #include <emmintrin.h>
  
  #include "webrtc/modules/video_processing/util/denoiser_filter_sse2.h"
  
  namespace webrtc {
  
  static void Get8x8varSse2(const uint8_t* src,
                            int src_stride,
                            const uint8_t* ref,
                            int ref_stride,
                            unsigned int* sse,
                            int* sum) {
    const __m128i zero = _mm_setzero_si128();
    __m128i vsum = _mm_setzero_si128();
    __m128i vsse = _mm_setzero_si128();
  
    for (int i = 0; i < 8; i += 2) {
      const __m128i src0 = _mm_unpacklo_epi8(
          _mm_loadl_epi64((const __m128i*)(src + i * src_stride)), zero);
      const __m128i ref0 = _mm_unpacklo_epi8(
          _mm_loadl_epi64((const __m128i*)(ref + i * ref_stride)), zero);
      const __m128i diff0 = _mm_sub_epi16(src0, ref0);
  
      const __m128i src1 = _mm_unpacklo_epi8(
          _mm_loadl_epi64((const __m128i*)(src + (i + 1) * src_stride)), zero);
      const __m128i ref1 = _mm_unpacklo_epi8(
          _mm_loadl_epi64((const __m128i*)(ref + (i + 1) * ref_stride)), zero);
      const __m128i diff1 = _mm_sub_epi16(src1, ref1);
  
      vsum = _mm_add_epi16(vsum, diff0);
      vsum = _mm_add_epi16(vsum, diff1);
      vsse = _mm_add_epi32(vsse, _mm_madd_epi16(diff0, diff0));
      vsse = _mm_add_epi32(vsse, _mm_madd_epi16(diff1, diff1));
    }
  
    // sum
    vsum = _mm_add_epi16(vsum, _mm_srli_si128(vsum, 8));
    vsum = _mm_add_epi16(vsum, _mm_srli_si128(vsum, 4));
    vsum = _mm_add_epi16(vsum, _mm_srli_si128(vsum, 2));
    *sum = static_cast<int>(_mm_extract_epi16(vsum, 0));
  
    // sse
    vsse = _mm_add_epi32(vsse, _mm_srli_si128(vsse, 8));
    vsse = _mm_add_epi32(vsse, _mm_srli_si128(vsse, 4));
    *sse = _mm_cvtsi128_si32(vsse);
  }
  
  static void VarianceSSE2(const unsigned char* src,
                           int src_stride,
                           const unsigned char* ref,
                           int ref_stride,
                           int w,
                           int h,
                           uint32_t* sse,
                           uint32_t* sum,
                           int block_size) {
    *sse = 0;
    *sum = 0;
  
    for (int i = 0; i < h; i += block_size) {
      for (int j = 0; j < w; j += block_size) {
        uint32_t sse0 = 0;
        int32_t sum0 = 0;
  
        Get8x8varSse2(src + src_stride * i + j, src_stride,
                      ref + ref_stride * i + j, ref_stride, &sse0, &sum0);
        *sse += sse0;
        *sum += sum0;
      }
    }
  }
  
  // Compute the sum of all pixel differences of this MB.
  static uint32_t AbsSumDiff16x1(__m128i acc_diff) {
    const __m128i k_1 = _mm_set1_epi16(1);
    const __m128i acc_diff_lo =
        _mm_srai_epi16(_mm_unpacklo_epi8(acc_diff, acc_diff), 8);
    const __m128i acc_diff_hi =
        _mm_srai_epi16(_mm_unpackhi_epi8(acc_diff, acc_diff), 8);
    const __m128i acc_diff_16 = _mm_add_epi16(acc_diff_lo, acc_diff_hi);
    const __m128i hg_fe_dc_ba = _mm_madd_epi16(acc_diff_16, k_1);
    const __m128i hgfe_dcba =
        _mm_add_epi32(hg_fe_dc_ba, _mm_srli_si128(hg_fe_dc_ba, 8));
    const __m128i hgfedcba =
        _mm_add_epi32(hgfe_dcba, _mm_srli_si128(hgfe_dcba, 4));
    unsigned int sum_diff = abs(_mm_cvtsi128_si32(hgfedcba));
  
    return sum_diff;
  }
  
  // TODO(jackychen): Optimize this function using SSE2.
  void DenoiserFilterSSE2::CopyMem16x16(const uint8_t* src,
                                        int src_stride,
                                        uint8_t* dst,
                                        int dst_stride) {
    for (int i = 0; i < 16; i++) {
      memcpy(dst, src, 16);
      src += src_stride;
      dst += dst_stride;
    }
  }
  
  // TODO(jackychen): Optimize this function using SSE2.
  void DenoiserFilterSSE2::CopyMem8x8(const uint8_t* src,
                                      int src_stride,
                                      uint8_t* dst,
                                      int dst_stride) {
    for (int i = 0; i < 8; i++) {
      memcpy(dst, src, 8);
      src += src_stride;
      dst += dst_stride;
    }
  }
  
  uint32_t DenoiserFilterSSE2::Variance16x8(const uint8_t* src,
                                            int src_stride,
                                            const uint8_t* ref,
                                            int ref_stride,
                                            unsigned int* sse) {
    uint32_t sum = 0;
    VarianceSSE2(src, src_stride, ref, ref_stride, 16, 8, sse, &sum, 8);
    return *sse - ((sum * sum) >> 7);
  }
  
  DenoiserDecision DenoiserFilterSSE2::MbDenoise(uint8_t* mc_running_avg_y,
                                                 int mc_avg_y_stride,
                                                 uint8_t* running_avg_y,
                                                 int avg_y_stride,
                                                 const uint8_t* sig,
                                                 int sig_stride,
                                                 uint8_t motion_magnitude,
                                                 int increase_denoising) {
    int shift_inc =
        (increase_denoising && motion_magnitude <= kMotionMagnitudeThreshold)
            ? 1
            : 0;
    __m128i acc_diff = _mm_setzero_si128();
    const __m128i k_0 = _mm_setzero_si128();
    const __m128i k_4 = _mm_set1_epi8(4 + shift_inc);
    const __m128i k_8 = _mm_set1_epi8(8);
    const __m128i k_16 = _mm_set1_epi8(16);
    // Modify each level's adjustment according to motion_magnitude.
    const __m128i l3 = _mm_set1_epi8(
        (motion_magnitude <= kMotionMagnitudeThreshold) ? 7 + shift_inc : 6);
    // Difference between level 3 and level 2 is 2.
    const __m128i l32 = _mm_set1_epi8(2);
    // Difference between level 2 and level 1 is 1.
    const __m128i l21 = _mm_set1_epi8(1);
  
    for (int r = 0; r < 16; ++r) {
      // Calculate differences.
      const __m128i v_sig =
          _mm_loadu_si128(reinterpret_cast<const __m128i*>(&sig[0]));
      const __m128i v_mc_running_avg_y =
          _mm_loadu_si128(reinterpret_cast<__m128i*>(&mc_running_avg_y[0]));
      __m128i v_running_avg_y;
      const __m128i pdiff = _mm_subs_epu8(v_mc_running_avg_y, v_sig);
      const __m128i ndiff = _mm_subs_epu8(v_sig, v_mc_running_avg_y);
      // Obtain the sign. FF if diff is negative.
      const __m128i diff_sign = _mm_cmpeq_epi8(pdiff, k_0);
      // Clamp absolute difference to 16 to be used to get mask. Doing this
      // allows us to use _mm_cmpgt_epi8, which operates on signed byte.
      const __m128i clamped_absdiff =
          _mm_min_epu8(_mm_or_si128(pdiff, ndiff), k_16);
      // Get masks for l2 l1 and l0 adjustments.
      const __m128i mask2 = _mm_cmpgt_epi8(k_16, clamped_absdiff);
      const __m128i mask1 = _mm_cmpgt_epi8(k_8, clamped_absdiff);
      const __m128i mask0 = _mm_cmpgt_epi8(k_4, clamped_absdiff);
      // Get adjustments for l2, l1, and l0.
      __m128i adj2 = _mm_and_si128(mask2, l32);
      const __m128i adj1 = _mm_and_si128(mask1, l21);
      const __m128i adj0 = _mm_and_si128(mask0, clamped_absdiff);
      __m128i adj, padj, nadj;
  
      // Combine the adjustments and get absolute adjustments.
      adj2 = _mm_add_epi8(adj2, adj1);
      adj = _mm_sub_epi8(l3, adj2);
      adj = _mm_andnot_si128(mask0, adj);
      adj = _mm_or_si128(adj, adj0);
  
      // Restore the sign and get positive and negative adjustments.
      padj = _mm_andnot_si128(diff_sign, adj);
      nadj = _mm_and_si128(diff_sign, adj);
  
      // Calculate filtered value.
      v_running_avg_y = _mm_adds_epu8(v_sig, padj);
      v_running_avg_y = _mm_subs_epu8(v_running_avg_y, nadj);
      _mm_storeu_si128(reinterpret_cast<__m128i*>(running_avg_y),
                       v_running_avg_y);
  
      // Adjustments <=7, and each element in acc_diff can fit in signed
      // char.
      acc_diff = _mm_adds_epi8(acc_diff, padj);
      acc_diff = _mm_subs_epi8(acc_diff, nadj);
  
      // Update pointers for next iteration.
      sig += sig_stride;
      mc_running_avg_y += mc_avg_y_stride;
      running_avg_y += avg_y_stride;
    }
  
    {
      // Compute the sum of all pixel differences of this MB.
      unsigned int abs_sum_diff = AbsSumDiff16x1(acc_diff);
      unsigned int sum_diff_thresh = kSumDiffThreshold;
      if (increase_denoising)
        sum_diff_thresh = kSumDiffThresholdHigh;
      if (abs_sum_diff > sum_diff_thresh) {
        // Before returning to copy the block (i.e., apply no denoising),
        // check if we can still apply some (weaker) temporal filtering to
        // this block, that would otherwise not be denoised at all. Simplest
        // is to apply an additional adjustment to running_avg_y to bring it
        // closer to sig. The adjustment is capped by a maximum delta, and
        // chosen such that in most cases the resulting sum_diff will be
        // within the acceptable range given by sum_diff_thresh.
  
        // The delta is set by the excess of absolute pixel diff over the
        // threshold.
        int delta = ((abs_sum_diff - sum_diff_thresh) >> 8) + 1;
        // Only apply the adjustment for max delta up to 3.
        if (delta < 4) {
          const __m128i k_delta = _mm_set1_epi8(delta);
          sig -= sig_stride * 16;
          mc_running_avg_y -= mc_avg_y_stride * 16;
          running_avg_y -= avg_y_stride * 16;
          for (int r = 0; r < 16; ++r) {
            __m128i v_running_avg_y =
                _mm_loadu_si128(reinterpret_cast<__m128i*>(&running_avg_y[0]));
            // Calculate differences.
            const __m128i v_sig =
                _mm_loadu_si128(reinterpret_cast<const __m128i*>(&sig[0]));
            const __m128i v_mc_running_avg_y = _mm_loadu_si128(
                reinterpret_cast<__m128i*>(&mc_running_avg_y[0]));
            const __m128i pdiff = _mm_subs_epu8(v_mc_running_avg_y, v_sig);
            const __m128i ndiff = _mm_subs_epu8(v_sig, v_mc_running_avg_y);
            // Obtain the sign. FF if diff is negative.
            const __m128i diff_sign = _mm_cmpeq_epi8(pdiff, k_0);
            // Clamp absolute difference to delta to get the adjustment.
            const __m128i adj = _mm_min_epu8(
                _mm_or_si128(pdiff, ndiff), k_delta);
            // Restore the sign and get positive and negative adjustments.
            __m128i padj, nadj;
            padj = _mm_andnot_si128(diff_sign, adj);
            nadj = _mm_and_si128(diff_sign, adj);
            // Calculate filtered value.
            v_running_avg_y = _mm_subs_epu8(v_running_avg_y, padj);
            v_running_avg_y = _mm_adds_epu8(v_running_avg_y, nadj);
            _mm_storeu_si128(reinterpret_cast<__m128i*>(running_avg_y),
                             v_running_avg_y);
  
            // Accumulate the adjustments.
            acc_diff = _mm_subs_epi8(acc_diff, padj);
            acc_diff = _mm_adds_epi8(acc_diff, nadj);
  
            // Update pointers for next iteration.
            sig += sig_stride;
            mc_running_avg_y += mc_avg_y_stride;
            running_avg_y += avg_y_stride;
          }
          abs_sum_diff = AbsSumDiff16x1(acc_diff);
          if (abs_sum_diff > sum_diff_thresh) {
            return COPY_BLOCK;
          }
        } else {
          return COPY_BLOCK;
        }
      }
    }
    return FILTER_BLOCK;
  }
  
  }  // namespace webrtc
  