// 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 <assert.h>

#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;

}

}

// -----------------------------------------------------------------------------