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add -print_psnr and -print_ssim options to cwebp.

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These will report the 7x7-averaged PSNR or SSIM, using the
new internal function WebPPictureDistortion().
This is for information only. These flags have no encoding impact.

+misc opportunistic cosmetics

Change-Id: I64c0a7eca679134d39062e438886274b22bb643f
This commit is contained in:
Pascal Massimino
2012-01-20 07:20:56 -08:00
parent 2e3e8b2ef5
commit d61479f95b
7 changed files with 165 additions and 26 deletions
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58
src/enc/filter.c
View File

@ -234,14 +234,21 @@ static void DoFilter(const VP8EncIterator* const it, int level) {
// SSIM metric
enum { KERNEL = 3 };
typedef struct {
double w, xm, ym, xxm, xym, yym;
} SSIMStats;
static const double kMinValue = 1.e-10; // minimal threshold
static void Accumulate(const uint8_t* src1, int stride1,
const uint8_t* src2, int stride2,
int xo, int yo, int W, int H,
SSIMStats* const stats) {
void VP8SSIMAddStats(const DistoStats* const src, DistoStats* const dst) {
dst->w += src->w;
dst->xm += src->xm;
dst->ym += src->ym;
dst->xxm += src->xxm;
dst->xym += src->xym;
dst->yym += src->yym;
}
static void VP8SSIMAccumulate(const uint8_t* src1, int stride1,
const uint8_t* src2, int stride2,
int xo, int yo, int W, int H,
DistoStats* const stats) {
const int ymin = (yo - KERNEL < 0) ? 0 : yo - KERNEL;
const int ymax = (yo + KERNEL > H - 1) ? H - 1 : yo + KERNEL;
const int xmin = (xo - KERNEL < 0) ? 0 : xo - KERNEL;
@ -263,7 +270,7 @@ static void Accumulate(const uint8_t* src1, int stride1,
}
}
static double GetSSIM(const SSIMStats* const stats) {
double VP8SSIMGet(const DistoStats* const stats) {
const double xmxm = stats->xm * stats->xm;
const double ymym = stats->ym * stats->ym;
const double xmym = stats->xm * stats->ym;
@ -281,26 +288,49 @@ static double GetSSIM(const SSIMStats* const stats) {
C2 = 58.5225 * w2;
fnum = (2 * xmym + C1) * (2 * sxy + C2);
fden = (xmxm + ymym + C1) * (sxx + syy + C2);
return (fden != 0) ? fnum / fden : 0.;
return (fden != 0.) ? fnum / fden : kMinValue;
}
double VP8SSIMGetSquaredError(const DistoStats* const s) {
if (s->w > 0.) {
const double iw2 = 1. / (s->w * s->w);
const double sxx = s->xxm * s->w - s->xm * s->xm;
const double syy = s->yym * s->w - s->ym * s->ym;
const double sxy = s->xym * s->w - s->xm * s->ym;
const double SSE = iw2 * (sxx + syy - 2. * sxy);
if (SSE > kMinValue) return SSE;
}
return kMinValue;
}
void VP8SSIMAccumulatePlane(const uint8_t* src1, int stride1,
const uint8_t* src2, int stride2,
int W, int H, DistoStats* const stats) {
int x, y;
for (y = 0; y < H; ++y) {
for (x = 0; x < W; ++x) {
VP8SSIMAccumulate(src1, stride1, src2, stride2, x, y, W, H, stats);
}
}
}
static double GetMBSSIM(const uint8_t* yuv1, const uint8_t* yuv2) {
int x, y;
SSIMStats s = { .0, .0, .0, .0, .0, .0 };
DistoStats s = { .0, .0, .0, .0, .0, .0 };
// compute SSIM in a 10 x 10 window
for (x = 3; x < 13; x++) {
for (y = 3; y < 13; y++) {
Accumulate(yuv1 + Y_OFF, BPS, yuv2 + Y_OFF, BPS, x, y, 16, 16, &s);
VP8SSIMAccumulate(yuv1 + Y_OFF, BPS, yuv2 + Y_OFF, BPS, x, y, 16, 16, &s);
}
}
for (x = 1; x < 7; x++) {
for (y = 1; y < 7; y++) {
Accumulate(yuv1 + U_OFF, BPS, yuv2 + U_OFF, BPS, x, y, 8, 8, &s);
Accumulate(yuv1 + V_OFF, BPS, yuv2 + V_OFF, BPS, x, y, 8, 8, &s);
VP8SSIMAccumulate(yuv1 + U_OFF, BPS, yuv2 + U_OFF, BPS, x, y, 8, 8, &s);
VP8SSIMAccumulate(yuv1 + V_OFF, BPS, yuv2 + V_OFF, BPS, x, y, 8, 8, &s);
}
}
return GetSSIM(&s);
return VP8SSIMGet(&s);
}
//------------------------------------------------------------------------------

54
src/enc/picture.c
View File

@ -11,6 +11,7 @@
#include <assert.h>
#include <stdlib.h>
#include <math.h>
#include "./vp8enci.h"
@ -659,7 +660,58 @@ void WebPCleanupTransparentArea(WebPPicture* const pic) {
#undef SIZE2
//------------------------------------------------------------------------------
// Simplest call:
// Distortion
// Max value returned in case of exact similarity.
static const double kMinDistortion_dB = 99.;
int WebPPictureDistortion(const WebPPicture* const pic1,
const WebPPicture* const pic2,
int type, float result[5]) {
int c;
DistoStats stats[5];
if (pic1->width != pic2->width ||
pic1->height != pic2->height ||
(pic1->a == NULL) != (pic2->a == NULL)) {
return 0;
}
memset(stats, 0, sizeof(stats));
VP8SSIMAccumulatePlane(pic1->y, pic1->y_stride,
pic2->y, pic2->y_stride,
pic1->width, pic1->height, &stats[0]);
VP8SSIMAccumulatePlane(pic1->u, pic1->uv_stride,
pic2->u, pic2->uv_stride,
(pic1->width + 1) >> 1, (pic1->height + 1) >> 1,
&stats[1]);
VP8SSIMAccumulatePlane(pic1->v, pic1->uv_stride,
pic2->v, pic2->uv_stride,
(pic1->width + 1) >> 1, (pic1->height + 1) >> 1,
&stats[2]);
if (pic1->a != NULL) {
VP8SSIMAccumulatePlane(pic1->a, pic1->a_stride,
pic2->a, pic2->a_stride,
pic1->width, pic1->height, &stats[3]);
}
for (c = 0; c <= 4; ++c) {
if (type == 1) {
const double v = VP8SSIMGet(&stats[c]);
result[c] = (v < 1.) ? -10.0 * log10(1. - v)
: kMinDistortion_dB;
} else {
const double v = VP8SSIMGetSquaredError(&stats[c]);
result[c] = (v > 0.) ? -4.3429448 * log(v / (255 * 255.))
: kMinDistortion_dB;
}
// Accumulate forward
if (c < 4) VP8SSIMAddStats(&stats[c], &stats[4]);
}
return 1;
}
//------------------------------------------------------------------------------
// Simplest high-level calls:
typedef int (*Importer)(WebPPicture* const, const uint8_t* const, int);

17
src/enc/vp8enci.h
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@ -455,9 +455,20 @@ int VP8EncFinishLayer(VP8Encoder* const enc); // finalize coding
void VP8EncDeleteLayer(VP8Encoder* enc); // reclaim memory
// in filter.c
extern void VP8InitFilter(VP8EncIterator* const it);
extern void VP8StoreFilterStats(VP8EncIterator* const it);
extern void VP8AdjustFilterStrength(VP8EncIterator* const it);
// SSIM utils
typedef struct { double w, xm, ym, xxm, xym, yym; } DistoStats;
void VP8SSIMAddStats(const DistoStats* const src, DistoStats* const dst);
void VP8SSIMAccumulatePlane(const uint8_t* src1, int stride1,
const uint8_t* src2, int stride2,
int W, int H, DistoStats* const stats);
double VP8SSIMGet(const DistoStats* const stats);
double VP8SSIMGetSquaredError(const DistoStats* const stats);
// autofilter
void VP8InitFilter(VP8EncIterator* const it);
void VP8StoreFilterStats(VP8EncIterator* const it);
void VP8AdjustFilterStrength(VP8EncIterator* const it);
//------------------------------------------------------------------------------

9
src/webp/encode.h
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@ -248,6 +248,15 @@ WEBP_EXTERN(void) WebPPictureFree(WebPPicture* const picture);
WEBP_EXTERN(int) WebPPictureCopy(const WebPPicture* const src,
WebPPicture* const dst);
// Compute PSNR or SSIM distortion between two pictures.
// Result is in dB, stores in result[] in the Y/U/V/Alpha/All order.
// Returns 0 in case of error (pic1 and pic2 don't have same dimension, ...)
// Warning: this function is rather CPU-intensive.
WEBP_EXTERN(int) WebPPictureDistortion(
const WebPPicture* const pic1, const WebPPicture* const pic2,
int metric_type, // 0 = PSNR, 1 = SSIM
float result[5]);
// self-crops a picture to the rectangle defined by top/left/width/height.
// Returns 0 in case of memory allocation error, or if the rectangle is
// outside of the source picture.