diff options
Diffstat (limited to 'third_party/libwebp/enc/picture_psnr.c')
| -rw-r--r-- | third_party/libwebp/enc/picture_psnr.c | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/third_party/libwebp/enc/picture_psnr.c b/third_party/libwebp/enc/picture_psnr.c new file mode 100644 index 0000000..2254b7e --- /dev/null +++ b/third_party/libwebp/enc/picture_psnr.c @@ -0,0 +1,150 @@ +// 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 "./vp8enci.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 float 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* s = src + j * src_stride; + for (i = x_0; i < x_1; ++i) { + const double sse = (double)(s[i] - value) * (s[i] - value); + if (sse < best_sse) best_sse = sse; + } + } + total_sse += best_sse; + } + } + return (float)total_sse; +} +#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 has_alpha; + int uv_w, uv_h; + + if (src == NULL || ref == NULL || + src->width != ref->width || src->height != ref->height || + src->y == NULL || ref->y == NULL || + src->u == NULL || ref->u == NULL || + src->v == NULL || ref->v == NULL || + result == NULL) { + return 0; + } + // TODO(skal): provide distortion for ARGB too. + if (src->use_argb == 1 || src->use_argb != ref->use_argb) { + 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; + } + + memset(stats, 0, sizeof(stats)); + + uv_w = (src->width + 1) >> 1; + uv_h = (src->height + 1) >> 1; + if (type >= 2) { + float sse[4]; + sse[0] = AccumulateLSIM(src->y, src->y_stride, + ref->y, ref->y_stride, src->width, src->height); + sse[1] = AccumulateLSIM(src->u, src->uv_stride, + ref->u, ref->uv_stride, uv_w, uv_h); + sse[2] = AccumulateLSIM(src->v, src->uv_stride, + ref->v, ref->uv_stride, uv_w, uv_h); + sse[3] = has_alpha ? AccumulateLSIM(src->a, src->a_stride, + ref->a, ref->a_stride, + src->width, src->height) + : 0.f; + result[0] = GetPSNR(sse[0] / (src->width * src->height)); + result[1] = GetPSNR(sse[1] / (uv_w * uv_h)); + result[2] = GetPSNR(sse[2] / (uv_w * uv_h)); + result[3] = GetPSNR(sse[3] / (src->width * src->height)); + { + double total_sse = sse[0] + sse[1] + sse[2]; + int total_pixels = src->width * src->height + 2 * uv_w * uv_h; + if (has_alpha) { + total_pixels += src->width * src->height; + total_sse += sse[3]; + } + result[4] = GetPSNR(total_sse / total_pixels); + } + } else { + int c; + VP8SSIMAccumulatePlane(src->y, src->y_stride, + ref->y, ref->y_stride, + src->width, src->height, &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, + src->width, src->height, &stats[3]); + } + 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; +} + +//------------------------------------------------------------------------------ |