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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
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@ -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);
}
//------------------------------------------------------------------------------