diff --git a/README b/README index 11676ff9..da72c90b 100644 --- a/README +++ b/README @@ -148,6 +148,8 @@ options: -crop .. crop picture with the given rectangle -resize ........ resize picture (after any cropping) -map ............. print map of extra info. + -print_ssim ............ prints averaged SSIM distortion. + -print_psnr ............ prints averaged PSNR distortion. -d .......... dump the compressed output (PGM file). -alpha_method .... Transparency-compression method (0..1) -alpha_filter . predictive filtering for alpha plane. diff --git a/examples/cwebp.c b/examples/cwebp.c index d9067dc0..9d31bb17 100644 --- a/examples/cwebp.c +++ b/examples/cwebp.c @@ -529,7 +529,8 @@ static void PrintValues(const int values[4]) { fprintf(stderr, "|\n"); } -static void PrintExtraInfo(const WebPPicture* const pic, int short_output) { +static void PrintExtraInfo(const WebPPicture* const pic, int short_output, + const char* const file_name) { const WebPAuxStats* const stats = pic->stats; if (short_output) { fprintf(stderr, "%7d %2.2f\n", stats->coded_size, stats->PSNR[3]); @@ -538,8 +539,11 @@ static void PrintExtraInfo(const WebPPicture* const pic, int short_output) { const int num_i16 = stats->block_count[1]; const int num_skip = stats->block_count[2]; const int total = num_i4 + num_i16; - fprintf(stderr, - "%7d bytes Y-U-V-All-PSNR %2.2f %2.2f %2.2f %2.2f dB\n", + fprintf(stderr, "File: %s\n", file_name); + fprintf(stderr, "Dimension: %d x %d%s\n", + pic->width, pic->height, (pic->a != NULL) ? " (with alpha)" : ""); + fprintf(stderr, "Output: " + "%d bytes Y-U-V-All-PSNR %2.2f %2.2f %2.2f %2.2f dB\n", stats->coded_size, stats->PSNR[0], stats->PSNR[1], stats->PSNR[2], stats->PSNR[3]); if (total > 0) { @@ -626,7 +630,7 @@ static int DumpPicture(const WebPPicture* const picture, const char* PGM_name) { const int alpha_height = picture->a ? picture->height : 0; const int height = picture->height + uv_height + alpha_height; FILE* const f = fopen(PGM_name, "wb"); - if (!f) return 0; + if (f == NULL) return 0; fprintf(f, "P5\n%d %d\n255\n", stride, height); for (y = 0; y < picture->height; ++y) { if (fwrite(picture->y + y * picture->y_stride, picture->width, 1, f) != 1) @@ -707,6 +711,8 @@ static void HelpLong(void) { printf(" -444 / -422 / -gray ..... Change colorspace\n"); #endif printf(" -map ............. print map of extra info.\n"); + printf(" -print_ssim ............ prints averaged SSIM distortion.\n"); + printf(" -print_psnr ............ prints averaged PSNR distortion.\n"); printf(" -d .......... dump the compressed output (PGM file).\n"); printf(" -alpha_method .... Transparency-compression method (0..1)\n"); printf(" -alpha_filter . predictive filtering for alpha plane.\n"); @@ -766,11 +772,15 @@ int main(int argc, const char *argv[]) { int resize_w = 0, resize_h = 0; int show_progress = 0; WebPPicture picture; + int print_distortion = 0; // 1=PSNR, 2=SSIM + WebPPicture original_picture; // when PSNR or SSIM is requested WebPConfig config; WebPAuxStats stats; Stopwatch stop_watch; - if (!WebPPictureInit(&picture) || !WebPConfigInit(&config)) { + if (!WebPPictureInit(&picture) || + !WebPPictureInit(&original_picture) || + !WebPConfigInit(&config)) { fprintf(stderr, "Error! Version mismatch!\n"); goto Error; } @@ -792,6 +802,12 @@ int main(int argc, const char *argv[]) { } else if (!strcmp(argv[c], "-d") && c < argc - 1) { dump_file = argv[++c]; config.show_compressed = 1; + } else if (!strcmp(argv[c], "-print_ssim")) { + config.show_compressed = 1; + print_distortion = 2; + } else if (!strcmp(argv[c], "-print_psnr")) { + config.show_compressed = 1; + print_distortion = 1; } else if (!strcmp(argv[c], "-short")) { short_output++; } else if (!strcmp(argv[c], "-s") && c < argc - 2) { @@ -919,7 +935,7 @@ int main(int argc, const char *argv[]) { StopwatchReadAndReset(&stop_watch); } if (!ReadPicture(in_file, &picture, keep_alpha)) { - fprintf(stderr, "Error! Cannot read input picture\n"); + fprintf(stderr, "Error! Cannot read input picture file '%s'\n", in_file); goto Error; } picture.progress_hook = (show_progress && !quiet) ? ProgressReport : NULL; @@ -932,7 +948,7 @@ int main(int argc, const char *argv[]) { // Open the output if (out_file) { out = fopen(out_file, "wb"); - if (!out) { + if (out == NULL) { fprintf(stderr, "Error! Cannot open output file '%s'\n", out_file); goto Error; } else { @@ -969,6 +985,9 @@ int main(int argc, const char *argv[]) { if (picture.extra_info_type > 0) { AllocExtraInfo(&picture); } + if (print_distortion > 0) { // Save original picture for later comparison + WebPPictureCopy(&picture, &original_picture); + } if (!WebPEncode(&config, &picture)) { fprintf(stderr, "Error! Cannot encode picture as WebP\n"); fprintf(stderr, "Error code: %d (%s)\n", @@ -984,13 +1003,23 @@ int main(int argc, const char *argv[]) { if (dump_file) { DumpPicture(&picture, dump_file); } + if (!quiet) { - PrintExtraInfo(&picture, short_output); + PrintExtraInfo(&picture, short_output, in_file); + } + if (!quiet && !short_output && print_distortion > 0) { // print distortion + float values[5]; + WebPPictureDistortion(&picture, &original_picture, + (print_distortion == 1) ? 0 : 1, values); + fprintf(stderr, "%s: Y:%.2f U:%.2f V:%.2f A:%.2f Total:%.2f\n", + (print_distortion == 1) ? "PSNR" : "SSIM", + values[0], values[1], values[2], values[3], values[4]); } Error: free(picture.extra_info); WebPPictureFree(&picture); + WebPPictureFree(&original_picture); if (out != NULL) { fclose(out); } diff --git a/man/cwebp.1 b/man/cwebp.1 index 2192fd5f..ec7ed8cf 100644 --- a/man/cwebp.1 +++ b/man/cwebp.1 @@ -168,6 +168,12 @@ Disable all assembly optimizations. .B \-v Print extra information (encoding time in particular). .TP +.B \-print_psnr +Compute and report average PSNR (Peak-Signal-To-Noise ratio). +.TP +.B \-print_ssim +Compute and report average SSIM (structural similarity metric) +.TP .B \-progress Report encoding progress in percent. .TP diff --git a/src/enc/filter.c b/src/enc/filter.c index ba659242..7fb78a39 100644 --- a/src/enc/filter.c +++ b/src/enc/filter.c @@ -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); } //------------------------------------------------------------------------------ diff --git a/src/enc/picture.c b/src/enc/picture.c index a4312fb9..3b284d12 100644 --- a/src/enc/picture.c +++ b/src/enc/picture.c @@ -11,6 +11,7 @@ #include #include +#include #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); diff --git a/src/enc/vp8enci.h b/src/enc/vp8enci.h index 2689139f..ce8492a5 100644 --- a/src/enc/vp8enci.h +++ b/src/enc/vp8enci.h @@ -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); //------------------------------------------------------------------------------ diff --git a/src/webp/encode.h b/src/webp/encode.h index 8dcac2f9..772ac252 100644 --- a/src/webp/encode.h +++ b/src/webp/encode.h @@ -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.