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// Copyright 2014 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.
// -----------------------------------------------------------------------------
//
// WebPPicture tools for measuring distortion
//
// Author: Skal (pascal.massimino@gmail.com)
#include <math.h>
#include <stdlib.h>
#include "./vp8i_enc.h"
#include "../utils/utils.h"
typedef double (*AccumulateFunc)(const uint8_t* src, int src_stride,
const uint8_t* ref, int ref_stride,
int w, int h);
//------------------------------------------------------------------------------
// local-min distortion
//
// For every pixel in the *reference* picture, we search for the local best
// match in the compressed image. This is not a symmetrical measure.
#define RADIUS 2 // search radius. Shouldn't be too large.
static double AccumulateLSIM(const uint8_t* src, int src_stride,
const uint8_t* ref, int ref_stride,
int w, int h) {
int x, y;
double total_sse = 0.;
for (y = 0; y < h; ++y) {
const int y_0 = (y - RADIUS < 0) ? 0 : y - RADIUS;
const int y_1 = (y + RADIUS + 1 >= h) ? h : y + RADIUS + 1;
for (x = 0; x < w; ++x) {
const int x_0 = (x - RADIUS < 0) ? 0 : x - RADIUS;
const int x_1 = (x + RADIUS + 1 >= w) ? w : x + RADIUS + 1;
double best_sse = 255. * 255.;
const double value = (double)ref[y * ref_stride + x];
int i, j;
for (j = y_0; j < y_1; ++j) {
const uint8_t* const s = src + j * src_stride;
for (i = x_0; i < x_1; ++i) {
const double diff = s[i] - value;
const double sse = diff * diff;
if (sse < best_sse) best_sse = sse;
}
}
total_sse += best_sse;
}
}
return total_sse;
}
#undef RADIUS
static double AccumulateSSE(const uint8_t* src, int src_stride,
const uint8_t* ref, int ref_stride,
int w, int h) {
int y;
double total_sse = 0.;
for (y = 0; y < h; ++y) {
total_sse += VP8AccumulateSSE(src, ref, w);
src += src_stride;
ref += ref_stride;
}
return total_sse;
}
//------------------------------------------------------------------------------
static double AccumulateSSIM(const uint8_t* src, int src_stride,
const uint8_t* ref, int ref_stride,
int w, int h) {
const int w0 = (w < VP8_SSIM_KERNEL) ? w : VP8_SSIM_KERNEL;
const int w1 = w - VP8_SSIM_KERNEL - 1;
const int h0 = (h < VP8_SSIM_KERNEL) ? h : VP8_SSIM_KERNEL;
const int h1 = h - VP8_SSIM_KERNEL - 1;
int x, y;
double sum = 0.;
for (y = 0; y < h0; ++y) {
for (x = 0; x < w; ++x) {
sum += VP8SSIMGetClipped(src, src_stride, ref, ref_stride, x, y, w, h);
}
}
for (; y < h1; ++y) {
for (x = 0; x < w0; ++x) {
sum += VP8SSIMGetClipped(src, src_stride, ref, ref_stride, x, y, w, h);
}
for (; x < w1; ++x) {
const int off1 = x - VP8_SSIM_KERNEL + (y - VP8_SSIM_KERNEL) * src_stride;
const int off2 = x - VP8_SSIM_KERNEL + (y - VP8_SSIM_KERNEL) * ref_stride;
sum += VP8SSIMGet(src + off1, src_stride, ref + off2, ref_stride);
}
for (; x < w; ++x) {
sum += VP8SSIMGetClipped(src, src_stride, ref, ref_stride, x, y, w, h);
}
}
for (; y < h; ++y) {
for (x = 0; x < w; ++x) {
sum += VP8SSIMGetClipped(src, src_stride, ref, ref_stride, x, y, w, h);
}
}
return sum;
}
//------------------------------------------------------------------------------
// Distortion
// Max value returned in case of exact similarity.
static const double kMinDistortion_dB = 99.;
static double GetPSNR(double v, double size) {
return (v > 0. && size > 0.) ? -4.3429448 * log(v / (size * 255 * 255.))
: kMinDistortion_dB;
}
static double GetLogSSIM(double v, double size) {
v = (size > 0.) ? v / size : 1.;
return (v < 1.) ? -10.0 * log10(1. - v) : kMinDistortion_dB;
}
int WebPPlaneDistortion(const uint8_t* src, size_t src_stride,
const uint8_t* ref, size_t ref_stride,
int width, int height, size_t x_step,
int type, float* distortion, float* result) {
uint8_t* allocated = NULL;
const AccumulateFunc metric = (type == 0) ? AccumulateSSE :
(type == 1) ? AccumulateSSIM :
AccumulateLSIM;
if (src == NULL || ref == NULL ||
src_stride < x_step * width || ref_stride < x_step * width ||
result == NULL || distortion == NULL) {
return 0;
}
VP8SSIMDspInit();
if (x_step != 1) { // extract a packed plane if needed
int x, y;
uint8_t* tmp1;
uint8_t* tmp2;
allocated =
(uint8_t*)WebPSafeMalloc(2ULL * width * height, sizeof(*allocated));
if (allocated == NULL) return 0;
tmp1 = allocated;
tmp2 = tmp1 + (size_t)width * height;
for (y = 0; y < height; ++y) {
for (x = 0; x < width; ++x) {
tmp1[x + y * width] = src[x * x_step + y * src_stride];
tmp2[x + y * width] = ref[x * x_step + y * ref_stride];
}
}
src = tmp1;
ref = tmp2;
}
*distortion = (float)metric(src, width, ref, width, width, height);
WebPSafeFree(allocated);
*result = (type == 1) ? (float)GetLogSSIM(*distortion, (double)width * height)
: (float)GetPSNR(*distortion, (double)width * height);
return 1;
}
int WebPPictureDistortion(const WebPPicture* src, const WebPPicture* ref,
int type, float results[5]) {
int w, h, c;
int ok = 0;
WebPPicture p0, p1;
double total_size = 0., total_distortion = 0.;
if (src == NULL || ref == NULL ||
src->width != ref->width || src->height != ref->height ||
results == NULL) {
return 0;
}
VP8SSIMDspInit();
if (!WebPPictureInit(&p0) || !WebPPictureInit(&p1)) return 0;
w = src->width;
h = src->height;
if (!WebPPictureView(src, 0, 0, w, h, &p0)) goto Error;
if (!WebPPictureView(ref, 0, 0, w, h, &p1)) goto Error;
// We always measure distortion in ARGB space.
if (p0.use_argb == 0 && !WebPPictureYUVAToARGB(&p0)) goto Error;
if (p1.use_argb == 0 && !WebPPictureYUVAToARGB(&p1)) goto Error;
for (c = 0; c < 4; ++c) {
float distortion;
const size_t stride0 = 4 * (size_t)p0.argb_stride;
const size_t stride1 = 4 * (size_t)p1.argb_stride;
if (!WebPPlaneDistortion((const uint8_t*)p0.argb + c, stride0,
(const uint8_t*)p1.argb + c, stride1,
w, h, 4, type, &distortion, results + c)) {
goto Error;
}
total_distortion += distortion;
total_size += w * h;
}
results[4] = (type == 1) ? (float)GetLogSSIM(total_distortion, total_size)
: (float)GetPSNR(total_distortion, total_size);
ok = 1;
Error:
WebPPictureFree(&p0);
WebPPictureFree(&p1);
return ok;
}
//------------------------------------------------------------------------------
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