// 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 "./vp8enci.h" #include "../utils/utils.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 void AccumulateLSIM(const uint8_t* src, int src_stride, const uint8_t* ref, int ref_stride, int w, int h, DistoStats* stats) { 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; } } stats->w = w * h; stats->xm = 0; stats->ym = 0; stats->xxm = total_sse; stats->yym = 0; stats->xxm = 0; } #undef RADIUS //------------------------------------------------------------------------------ // Distortion // Max value returned in case of exact similarity. static const double kMinDistortion_dB = 99.; static float GetPSNR(const double v) { return (float)((v > 0.) ? -4.3429448 * log(v / (255 * 255.)) : kMinDistortion_dB); } int WebPPictureDistortion(const WebPPicture* src, const WebPPicture* ref, int type, float result[5]) { DistoStats stats[5]; int w, h; memset(stats, 0, sizeof(stats)); if (src == NULL || ref == NULL || src->width != ref->width || src->height != ref->height || src->use_argb != ref->use_argb || result == NULL) { return 0; } w = src->width; h = src->height; if (src->use_argb == 1) { if (src->argb == NULL || ref->argb == NULL) { return 0; } else { int i, j, c; uint8_t* tmp1, *tmp2; uint8_t* const tmp_plane = (uint8_t*)WebPSafeMalloc(2ULL * w * h, sizeof(*tmp_plane)); if (tmp_plane == NULL) return 0; tmp1 = tmp_plane; tmp2 = tmp_plane + w * h; for (c = 0; c < 4; ++c) { for (j = 0; j < h; ++j) { for (i = 0; i < w; ++i) { tmp1[j * w + i] = src->argb[i + j * src->argb_stride] >> (c * 8); tmp2[j * w + i] = ref->argb[i + j * ref->argb_stride] >> (c * 8); } } if (type >= 2) { AccumulateLSIM(tmp1, w, tmp2, w, w, h, &stats[c]); } else { VP8SSIMAccumulatePlane(tmp1, w, tmp2, w, w, h, &stats[c]); } } free(tmp_plane); } } else { int has_alpha, uv_w, uv_h; if (src->y == NULL || ref->y == NULL || src->u == NULL || ref->u == NULL || src->v == NULL || ref->v == NULL) { return 0; } has_alpha = !!(src->colorspace & WEBP_CSP_ALPHA_BIT); if (has_alpha != !!(ref->colorspace & WEBP_CSP_ALPHA_BIT) || (has_alpha && (src->a == NULL || ref->a == NULL))) { return 0; } uv_w = (src->width + 1) >> 1; uv_h = (src->height + 1) >> 1; if (type >= 2) { AccumulateLSIM(src->y, src->y_stride, ref->y, ref->y_stride, w, h, &stats[0]); AccumulateLSIM(src->u, src->uv_stride, ref->u, ref->uv_stride, uv_w, uv_h, &stats[1]); AccumulateLSIM(src->v, src->uv_stride, ref->v, ref->uv_stride, uv_w, uv_h, &stats[2]); if (has_alpha) { AccumulateLSIM(src->a, src->a_stride, ref->a, ref->a_stride, w, h, &stats[3]); } } else { VP8SSIMAccumulatePlane(src->y, src->y_stride, ref->y, ref->y_stride, w, h, &stats[0]); VP8SSIMAccumulatePlane(src->u, src->uv_stride, ref->u, ref->uv_stride, uv_w, uv_h, &stats[1]); VP8SSIMAccumulatePlane(src->v, src->uv_stride, ref->v, ref->uv_stride, uv_w, uv_h, &stats[2]); if (has_alpha) { VP8SSIMAccumulatePlane(src->a, src->a_stride, ref->a, ref->a_stride, w, h, &stats[3]); } } } // Final stat calculations. { int c; for (c = 0; c <= 4; ++c) { if (type == 1) { const double v = VP8SSIMGet(&stats[c]); result[c] = (float)((v < 1.) ? -10.0 * log10(1. - v) : kMinDistortion_dB); } else { const double v = VP8SSIMGetSquaredError(&stats[c]); result[c] = GetPSNR(v); } // Accumulate forward if (c < 4) VP8SSIMAddStats(&stats[c], &stats[4]); } } return 1; } //------------------------------------------------------------------------------