godot/thirdparty/libwebp/src/enc/filter_enc.c

// 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: [email protected] (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 …
static const uint8_t kLevelsFromDelta[8][MAX_DELTA_SIZE] = …;

int VP8FilterStrengthFromDelta(int sharpness, int delta) { … }

//------------------------------------------------------------------------------
// Paragraph 15.4: compute the inner-edge filtering strength

#if !defined(WEBP_REDUCE_SIZE)

static int GetILevel(int sharpness, int level) { … }

static void DoFilter(const VP8EncIterator* const it, int level) { … }

//------------------------------------------------------------------------------
// SSIM metric for one macroblock

static double GetMBSSIM(const uint8_t* yuv1, const uint8_t* yuv2) { … }

#endif  // !defined(WEBP_REDUCE_SIZE)

//------------------------------------------------------------------------------
// Exposed APIs: Encoder should call the following 3 functions to adjust
// loop filter strength

void VP8InitFilter(VP8EncIterator* const it) { … }

void VP8StoreFilterStats(VP8EncIterator* const it) { … }

void VP8AdjustFilterStrength(VP8EncIterator* const it) { … }

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