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Diffstat (limited to 'files/util/ssim.cc')
| -rw-r--r-- | files/util/ssim.cc | 336 |
1 files changed, 336 insertions, 0 deletions
diff --git a/files/util/ssim.cc b/files/util/ssim.cc new file mode 100644 index 00000000..5a6399b7 --- /dev/null +++ b/files/util/ssim.cc @@ -0,0 +1,336 @@ +/* + * Copyright 2013 The LibYuv Project Authors. All rights reserved. + * + * Use of this source code is governed by a BSD-style license + * that can be found in the LICENSE 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. + */ + +#include "../util/ssim.h" // NOLINT + +#include <string.h> + +#ifdef __cplusplus +extern "C" { +#endif + +typedef unsigned int uint32; // NOLINT +typedef unsigned short uint16; // NOLINT + +#if !defined(LIBYUV_DISABLE_X86) && !defined(__SSE2__) && \ + (defined(_M_X64) || (defined(_M_IX86_FP) && (_M_IX86_FP >= 2))) +#define __SSE2__ +#endif +#if !defined(LIBYUV_DISABLE_X86) && defined(__SSE2__) +#include <emmintrin.h> +#endif + +#ifdef _OPENMP +#include <omp.h> +#endif + +// SSIM +enum { KERNEL = 3, KERNEL_SIZE = 2 * KERNEL + 1 }; + +// Symmetric Gaussian kernel: K[i] = ~11 * exp(-0.3 * i * i) +// The maximum value (11 x 11) must be less than 128 to avoid sign +// problems during the calls to _mm_mullo_epi16(). +static const int K[KERNEL_SIZE] = { + 1, 3, 7, 11, 7, 3, 1 // ~11 * exp(-0.3 * i * i) +}; +static const double kiW[KERNEL + 1 + 1] = { + 1. / 1089., // 1 / sum(i:0..6, j..6) K[i]*K[j] + 1. / 1089., // 1 / sum(i:0..6, j..6) K[i]*K[j] + 1. / 1056., // 1 / sum(i:0..5, j..6) K[i]*K[j] + 1. / 957., // 1 / sum(i:0..4, j..6) K[i]*K[j] + 1. / 726., // 1 / sum(i:0..3, j..6) K[i]*K[j] +}; + +#if !defined(LIBYUV_DISABLE_X86) && defined(__SSE2__) + +#define PWEIGHT(A, B) static_cast<uint16>(K[(A)] * K[(B)]) // weight product +#define MAKE_WEIGHT(L) \ + { { { PWEIGHT(L, 0), PWEIGHT(L, 1), PWEIGHT(L, 2), PWEIGHT(L, 3), \ + PWEIGHT(L, 4), PWEIGHT(L, 5), PWEIGHT(L, 6), 0 } } } + +// We need this union trick to be able to initialize constant static __m128i +// values. We can't call _mm_set_epi16() for static compile-time initialization. +static const struct { + union { + uint16 i16_[8]; + __m128i m_; + } values_; +} W0 = MAKE_WEIGHT(0), + W1 = MAKE_WEIGHT(1), + W2 = MAKE_WEIGHT(2), + W3 = MAKE_WEIGHT(3); + // ... the rest is symmetric. +#undef MAKE_WEIGHT +#undef PWEIGHT +#endif + +// Common final expression for SSIM, once the weighted sums are known. +static double FinalizeSSIM(double iw, double xm, double ym, + double xxm, double xym, double yym) { + const double iwx = xm * iw; + const double iwy = ym * iw; + double sxx = xxm * iw - iwx * iwx; + double syy = yym * iw - iwy * iwy; + // small errors are possible, due to rounding. Clamp to zero. + if (sxx < 0.) sxx = 0.; + if (syy < 0.) syy = 0.; + const double sxsy = sqrt(sxx * syy); + const double sxy = xym * iw - iwx * iwy; + static const double C11 = (0.01 * 0.01) * (255 * 255); + static const double C22 = (0.03 * 0.03) * (255 * 255); + static const double C33 = (0.015 * 0.015) * (255 * 255); + const double l = (2. * iwx * iwy + C11) / (iwx * iwx + iwy * iwy + C11); + const double c = (2. * sxsy + C22) / (sxx + syy + C22); + const double s = (sxy + C33) / (sxsy + C33); + return l * c * s; +} + +// GetSSIM() does clipping. GetSSIMFullKernel() does not + +// TODO(skal): use summed tables? +// Note: worst case of accumulation is a weight of 33 = 11 + 2 * (7 + 3 + 1) +// with a diff of 255, squared. The maximum error is thus 0x4388241, +// which fits into 32 bits integers. +double GetSSIM(const uint8 *org, const uint8 *rec, + int xo, int yo, int W, int H, int stride) { + uint32 ws = 0, xm = 0, ym = 0, xxm = 0, xym = 0, yym = 0; + org += (yo - KERNEL) * stride; + org += (xo - KERNEL); + rec += (yo - KERNEL) * stride; + rec += (xo - KERNEL); + for (int y_ = 0; y_ < KERNEL_SIZE; ++y_, org += stride, rec += stride) { + if (((yo - KERNEL + y_) < 0) || ((yo - KERNEL + y_) >= H)) continue; + const int Wy = K[y_]; + for (int x_ = 0; x_ < KERNEL_SIZE; ++x_) { + const int Wxy = Wy * K[x_]; + if (((xo - KERNEL + x_) >= 0) && ((xo - KERNEL + x_) < W)) { + const int org_x = org[x_]; + const int rec_x = rec[x_]; + ws += Wxy; + xm += Wxy * org_x; + ym += Wxy * rec_x; + xxm += Wxy * org_x * org_x; + xym += Wxy * org_x * rec_x; + yym += Wxy * rec_x * rec_x; + } + } + } + return FinalizeSSIM(1. / ws, xm, ym, xxm, xym, yym); +} + +double GetSSIMFullKernel(const uint8 *org, const uint8 *rec, + int xo, int yo, int stride, + double area_weight) { + uint32 xm = 0, ym = 0, xxm = 0, xym = 0, yym = 0; + +#if defined(LIBYUV_DISABLE_X86) || !defined(__SSE2__) + + org += yo * stride + xo; + rec += yo * stride + xo; + for (int y = 1; y <= KERNEL; y++) { + const int dy1 = y * stride; + const int dy2 = y * stride; + const int Wy = K[KERNEL + y]; + + for (int x = 1; x <= KERNEL; x++) { + // Compute the contributions of upper-left (ul), upper-right (ur) + // lower-left (ll) and lower-right (lr) points (see the diagram below). + // Symmetric Kernel will have same weight on those points. + // - - - - - - - + // - ul - - - ur - + // - - - - - - - + // - - - 0 - - - + // - - - - - - - + // - ll - - - lr - + // - - - - - - - + const int Wxy = Wy * K[KERNEL + x]; + const int ul1 = org[-dy1 - x]; + const int ur1 = org[-dy1 + x]; + const int ll1 = org[dy1 - x]; + const int lr1 = org[dy1 + x]; + + const int ul2 = rec[-dy2 - x]; + const int ur2 = rec[-dy2 + x]; + const int ll2 = rec[dy2 - x]; + const int lr2 = rec[dy2 + x]; + + xm += Wxy * (ul1 + ur1 + ll1 + lr1); + ym += Wxy * (ul2 + ur2 + ll2 + lr2); + xxm += Wxy * (ul1 * ul1 + ur1 * ur1 + ll1 * ll1 + lr1 * lr1); + xym += Wxy * (ul1 * ul2 + ur1 * ur2 + ll1 * ll2 + lr1 * lr2); + yym += Wxy * (ul2 * ul2 + ur2 * ur2 + ll2 * ll2 + lr2 * lr2); + } + + // Compute the contributions of up (u), down (d), left (l) and right (r) + // points across the main axes (see the diagram below). + // Symmetric Kernel will have same weight on those points. + // - - - - - - - + // - - - u - - - + // - - - - - - - + // - l - 0 - r - + // - - - - - - - + // - - - d - - - + // - - - - - - - + const int Wxy = Wy * K[KERNEL]; + const int u1 = org[-dy1]; + const int d1 = org[dy1]; + const int l1 = org[-y]; + const int r1 = org[y]; + + const int u2 = rec[-dy2]; + const int d2 = rec[dy2]; + const int l2 = rec[-y]; + const int r2 = rec[y]; + + xm += Wxy * (u1 + d1 + l1 + r1); + ym += Wxy * (u2 + d2 + l2 + r2); + xxm += Wxy * (u1 * u1 + d1 * d1 + l1 * l1 + r1 * r1); + xym += Wxy * (u1 * u2 + d1 * d2 + l1 * l2 + r1 * r2); + yym += Wxy * (u2 * u2 + d2 * d2 + l2 * l2 + r2 * r2); + } + + // Lastly the contribution of (x0, y0) point. + const int Wxy = K[KERNEL] * K[KERNEL]; + const int s1 = org[0]; + const int s2 = rec[0]; + + xm += Wxy * s1; + ym += Wxy * s2; + xxm += Wxy * s1 * s1; + xym += Wxy * s1 * s2; + yym += Wxy * s2 * s2; + +#else // __SSE2__ + + org += (yo - KERNEL) * stride + (xo - KERNEL); + rec += (yo - KERNEL) * stride + (xo - KERNEL); + + const __m128i zero = _mm_setzero_si128(); + __m128i x = zero; + __m128i y = zero; + __m128i xx = zero; + __m128i xy = zero; + __m128i yy = zero; + +// Read 8 pixels at line #L, and convert to 16bit, perform weighting +// and acccumulate. +#define LOAD_LINE_PAIR(L, WEIGHT) do { \ + const __m128i v0 = \ + _mm_loadl_epi64(reinterpret_cast<const __m128i*>(org + (L) * stride)); \ + const __m128i v1 = \ + _mm_loadl_epi64(reinterpret_cast<const __m128i*>(rec + (L) * stride)); \ + const __m128i w0 = _mm_unpacklo_epi8(v0, zero); \ + const __m128i w1 = _mm_unpacklo_epi8(v1, zero); \ + const __m128i ww0 = _mm_mullo_epi16(w0, (WEIGHT).values_.m_); \ + const __m128i ww1 = _mm_mullo_epi16(w1, (WEIGHT).values_.m_); \ + x = _mm_add_epi32(x, _mm_unpacklo_epi16(ww0, zero)); \ + y = _mm_add_epi32(y, _mm_unpacklo_epi16(ww1, zero)); \ + x = _mm_add_epi32(x, _mm_unpackhi_epi16(ww0, zero)); \ + y = _mm_add_epi32(y, _mm_unpackhi_epi16(ww1, zero)); \ + xx = _mm_add_epi32(xx, _mm_madd_epi16(ww0, w0)); \ + xy = _mm_add_epi32(xy, _mm_madd_epi16(ww0, w1)); \ + yy = _mm_add_epi32(yy, _mm_madd_epi16(ww1, w1)); \ +} while (0) + +#define ADD_AND_STORE_FOUR_EPI32(M, OUT) do { \ + uint32 tmp[4]; \ + _mm_storeu_si128(reinterpret_cast<__m128i*>(tmp), (M)); \ + (OUT) = tmp[3] + tmp[2] + tmp[1] + tmp[0]; \ +} while (0) + + LOAD_LINE_PAIR(0, W0); + LOAD_LINE_PAIR(1, W1); + LOAD_LINE_PAIR(2, W2); + LOAD_LINE_PAIR(3, W3); + LOAD_LINE_PAIR(4, W2); + LOAD_LINE_PAIR(5, W1); + LOAD_LINE_PAIR(6, W0); + + ADD_AND_STORE_FOUR_EPI32(x, xm); + ADD_AND_STORE_FOUR_EPI32(y, ym); + ADD_AND_STORE_FOUR_EPI32(xx, xxm); + ADD_AND_STORE_FOUR_EPI32(xy, xym); + ADD_AND_STORE_FOUR_EPI32(yy, yym); + +#undef LOAD_LINE_PAIR +#undef ADD_AND_STORE_FOUR_EPI32 +#endif + + return FinalizeSSIM(area_weight, xm, ym, xxm, xym, yym); +} + +static int start_max(int x, int y) { return (x > y) ? x : y; } + +double CalcSSIM(const uint8 *org, const uint8 *rec, + const int image_width, const int image_height) { + double SSIM = 0.; + const int KERNEL_Y = (image_height < KERNEL) ? image_height : KERNEL; + const int KERNEL_X = (image_width < KERNEL) ? image_width : KERNEL; + const int start_x = start_max(image_width - 8 + KERNEL_X, KERNEL_X); + const int start_y = start_max(image_height - KERNEL_Y, KERNEL_Y); + const int stride = image_width; + + for (int j = 0; j < KERNEL_Y; ++j) { + for (int i = 0; i < image_width; ++i) { + SSIM += GetSSIM(org, rec, i, j, image_width, image_height, stride); + } + } + +#ifdef _OPENMP + #pragma omp parallel for reduction(+: SSIM) +#endif + for (int j = KERNEL_Y; j < image_height - KERNEL_Y; ++j) { + for (int i = 0; i < KERNEL_X; ++i) { + SSIM += GetSSIM(org, rec, i, j, image_width, image_height, stride); + } + for (int i = KERNEL_X; i < start_x; ++i) { + SSIM += GetSSIMFullKernel(org, rec, i, j, stride, kiW[0]); + } + if (start_x < image_width) { + // GetSSIMFullKernel() needs to be able to read 8 pixels (in SSE2). So we + // copy the 8 rightmost pixels on a cache area, and pad this area with + // zeros which won't contribute to the overall SSIM value (but we need + // to pass the correct normalizing constant!). By using this cache, we can + // still call GetSSIMFullKernel() instead of the slower GetSSIM(). + // NOTE: we could use similar method for the left-most pixels too. + const int kScratchWidth = 8; + const int kScratchStride = kScratchWidth + KERNEL + 1; + uint8 scratch_org[KERNEL_SIZE * kScratchStride] = { 0 }; + uint8 scratch_rec[KERNEL_SIZE * kScratchStride] = { 0 }; + + for (int k = 0; k < KERNEL_SIZE; ++k) { + const int offset = + (j - KERNEL + k) * stride + image_width - kScratchWidth; + memcpy(scratch_org + k * kScratchStride, org + offset, kScratchWidth); + memcpy(scratch_rec + k * kScratchStride, rec + offset, kScratchWidth); + } + for (int k = 0; k <= KERNEL_X + 1; ++k) { + SSIM += GetSSIMFullKernel(scratch_org, scratch_rec, + KERNEL + k, KERNEL, kScratchStride, kiW[k]); + } + } + } + + for (int j = start_y; j < image_height; ++j) { + for (int i = 0; i < image_width; ++i) { + SSIM += GetSSIM(org, rec, i, j, image_width, image_height, stride); + } + } + return SSIM; +} + +double CalcLSSIM(double ssim) { + return -10.0 * log10(1.0 - ssim); +} + +#ifdef __cplusplus +} // extern "C" +#endif + |