// Copyright 2011 Google Inc. All Rights Reserved. // // Use of this source code is governed by a BSD-style license // that can be found in the COPYING 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. // ----------------------------------------------------------------------------- // // Selecting filter level // // Author: somnath@google.com (Somnath Banerjee) #include #include "src/enc/vp8i_enc.h" #include "src/dsp/dsp.h" // This table gives, for a given sharpness, the filtering strength to be // used (at least) in order to filter a given edge step delta. // This is constructed by brute force inspection: for all delta, we iterate // over all possible filtering strength / thresh until needs_filter() returns // true. #define MAX_DELTA_SIZE 64 static const uint8_t kLevelsFromDelta[8][MAX_DELTA_SIZE] = { { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63 }, { 0, 1, 2, 3, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15, 17, 18, 20, 21, 23, 24, 26, 27, 29, 30, 32, 33, 35, 36, 38, 39, 41, 42, 44, 45, 47, 48, 50, 51, 53, 54, 56, 57, 59, 60, 62, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63 }, { 0, 1, 2, 3, 5, 6, 7, 8, 9, 11, 12, 13, 14, 16, 17, 19, 20, 22, 23, 25, 26, 28, 29, 31, 32, 34, 35, 37, 38, 40, 41, 43, 44, 46, 47, 49, 50, 52, 53, 55, 56, 58, 59, 61, 62, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63 }, { 0, 1, 2, 3, 5, 6, 7, 8, 9, 11, 12, 13, 15, 16, 18, 19, 21, 22, 24, 25, 27, 28, 30, 31, 33, 34, 36, 37, 39, 40, 42, 43, 45, 46, 48, 49, 51, 52, 54, 55, 57, 58, 60, 61, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63 }, { 0, 1, 2, 3, 5, 6, 7, 8, 9, 11, 12, 14, 15, 17, 18, 20, 21, 23, 24, 26, 27, 29, 30, 32, 33, 35, 36, 38, 39, 41, 42, 44, 45, 47, 48, 50, 51, 53, 54, 56, 57, 59, 60, 62, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63 }, { 0, 1, 2, 4, 5, 7, 8, 9, 11, 12, 13, 15, 16, 17, 19, 20, 22, 23, 25, 26, 28, 29, 31, 32, 34, 35, 37, 38, 40, 41, 43, 44, 46, 47, 49, 50, 52, 53, 55, 56, 58, 59, 61, 62, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63 }, { 0, 1, 2, 4, 5, 7, 8, 9, 11, 12, 13, 15, 16, 18, 19, 21, 22, 24, 25, 27, 28, 30, 31, 33, 34, 36, 37, 39, 40, 42, 43, 45, 46, 48, 49, 51, 52, 54, 55, 57, 58, 60, 61, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63 }, { 0, 1, 2, 4, 5, 7, 8, 9, 11, 12, 14, 15, 17, 18, 20, 21, 23, 24, 26, 27, 29, 30, 32, 33, 35, 36, 38, 39, 41, 42, 44, 45, 47, 48, 50, 51, 53, 54, 56, 57, 59, 60, 62, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63 } }; int VP8FilterStrengthFromDelta(int sharpness, int delta) { const int pos = (delta < MAX_DELTA_SIZE) ? delta : MAX_DELTA_SIZE - 1; assert(sharpness >= 0 && sharpness <= 7); return kLevelsFromDelta[sharpness][pos]; } //------------------------------------------------------------------------------ // Paragraph 15.4: compute the inner-edge filtering strength #if !defined(WEBP_REDUCE_SIZE) static int GetILevel(int sharpness, int level) { if (sharpness > 0) { if (sharpness > 4) { level >>= 2; } else { level >>= 1; } if (level > 9 - sharpness) { level = 9 - sharpness; } } if (level < 1) level = 1; return level; } static void DoFilter(const VP8EncIterator* const it, int level) { const VP8Encoder* const enc = it->enc_; const int ilevel = GetILevel(enc->config_->filter_sharpness, level); const int limit = 2 * level + ilevel; uint8_t* const y_dst = it->yuv_out2_ + Y_OFF_ENC; uint8_t* const u_dst = it->yuv_out2_ + U_OFF_ENC; uint8_t* const v_dst = it->yuv_out2_ + V_OFF_ENC; // copy current block to yuv_out2_ memcpy(y_dst, it->yuv_out_, YUV_SIZE_ENC * sizeof(uint8_t)); if (enc->filter_hdr_.simple_ == 1) { // simple VP8SimpleHFilter16i(y_dst, BPS, limit); VP8SimpleVFilter16i(y_dst, BPS, limit); } else { // complex const int hev_thresh = (level >= 40) ? 2 : (level >= 15) ? 1 : 0; VP8HFilter16i(y_dst, BPS, limit, ilevel, hev_thresh); VP8HFilter8i(u_dst, v_dst, BPS, limit, ilevel, hev_thresh); VP8VFilter16i(y_dst, BPS, limit, ilevel, hev_thresh); VP8VFilter8i(u_dst, v_dst, BPS, limit, ilevel, hev_thresh); } } //------------------------------------------------------------------------------ // SSIM metric for one macroblock static double GetMBSSIM(const uint8_t* yuv1, const uint8_t* yuv2) { int x, y; double sum = 0.; // compute SSIM in a 10 x 10 window for (y = VP8_SSIM_KERNEL; y < 16 - VP8_SSIM_KERNEL; y++) { for (x = VP8_SSIM_KERNEL; x < 16 - VP8_SSIM_KERNEL; x++) { sum += VP8SSIMGetClipped(yuv1 + Y_OFF_ENC, BPS, yuv2 + Y_OFF_ENC, BPS, x, y, 16, 16); } } for (x = 1; x < 7; x++) { for (y = 1; y < 7; y++) { sum += VP8SSIMGetClipped(yuv1 + U_OFF_ENC, BPS, yuv2 + U_OFF_ENC, BPS, x, y, 8, 8); sum += VP8SSIMGetClipped(yuv1 + V_OFF_ENC, BPS, yuv2 + V_OFF_ENC, BPS, x, y, 8, 8); } } return sum; } #endif // !defined(WEBP_REDUCE_SIZE) //------------------------------------------------------------------------------ // Exposed APIs: Encoder should call the following 3 functions to adjust // loop filter strength void VP8InitFilter(VP8EncIterator* const it) { #if !defined(WEBP_REDUCE_SIZE) if (it->lf_stats_ != NULL) { int s, i; for (s = 0; s < NUM_MB_SEGMENTS; s++) { for (i = 0; i < MAX_LF_LEVELS; i++) { (*it->lf_stats_)[s][i] = 0; } } VP8SSIMDspInit(); } #else (void)it; #endif } void VP8StoreFilterStats(VP8EncIterator* const it) { #if !defined(WEBP_REDUCE_SIZE) int d; VP8Encoder* const enc = it->enc_; const int s = it->mb_->segment_; const int level0 = enc->dqm_[s].fstrength_; // explore +/-quant range of values around level0 const int delta_min = -enc->dqm_[s].quant_; const int delta_max = enc->dqm_[s].quant_; const int step_size = (delta_max - delta_min >= 4) ? 4 : 1; if (it->lf_stats_ == NULL) return; // NOTE: Currently we are applying filter only across the sublock edges // There are two reasons for that. // 1. Applying filter on macro block edges will change the pixels in // the left and top macro blocks. That will be hard to restore // 2. Macro Blocks on the bottom and right are not yet compressed. So we // cannot apply filter on the right and bottom macro block edges. if (it->mb_->type_ == 1 && it->mb_->skip_) return; // Always try filter level zero (*it->lf_stats_)[s][0] += GetMBSSIM(it->yuv_in_, it->yuv_out_); for (d = delta_min; d <= delta_max; d += step_size) { const int level = level0 + d; if (level <= 0 || level >= MAX_LF_LEVELS) { continue; } DoFilter(it, level); (*it->lf_stats_)[s][level] += GetMBSSIM(it->yuv_in_, it->yuv_out2_); } #else // defined(WEBP_REDUCE_SIZE) (void)it; #endif // !defined(WEBP_REDUCE_SIZE) } void VP8AdjustFilterStrength(VP8EncIterator* const it) { VP8Encoder* const enc = it->enc_; #if !defined(WEBP_REDUCE_SIZE) if (it->lf_stats_ != NULL) { int s; for (s = 0; s < NUM_MB_SEGMENTS; s++) { int i, best_level = 0; // Improvement over filter level 0 should be at least 1e-5 (relatively) double best_v = 1.00001 * (*it->lf_stats_)[s][0]; for (i = 1; i < MAX_LF_LEVELS; i++) { const double v = (*it->lf_stats_)[s][i]; if (v > best_v) { best_v = v; best_level = i; } } enc->dqm_[s].fstrength_ = best_level; } return; } #endif // !defined(WEBP_REDUCE_SIZE) if (enc->config_->filter_strength > 0) { int max_level = 0; int s; for (s = 0; s < NUM_MB_SEGMENTS; s++) { VP8SegmentInfo* const dqm = &enc->dqm_[s]; // this '>> 3' accounts for some inverse WHT scaling const int delta = (dqm->max_edge_ * dqm->y2_.q_[1]) >> 3; const int level = VP8FilterStrengthFromDelta(enc->filter_hdr_.sharpness_, delta); if (level > dqm->fstrength_) { dqm->fstrength_ = level; } if (max_level < dqm->fstrength_) { max_level = dqm->fstrength_; } } enc->filter_hdr_.level_ = max_level; } } // -----------------------------------------------------------------------------