'extras/get_disto' example: compute PSNR between two files

Change-Id: I40e693e52d8eb4e32b86273952dac2e5eefe6e7c

extras/Makefile.am

@@ -9,3 +9,11 @@ libwebpextras_la_SOURCES += extras.c extras.h
 
 libwebpextras_la_CPPFLAGS = $(AM_CPPFLAGS)
 libwebpextras_la_LIBADD = ../src/libwebp.la
+
+noinst_PROGRAMS = get_disto
+
+get_disto_SOURCES = get_disto.c
+get_disto_CPPFLAGS  = $(AM_CPPFLAGS)
+get_disto_LDADD = ../imageio/libexample_util.la ../imageio/libimagedec.la
+get_disto_LDADD += ../src/libwebp.la
+get_disto_LDADD += $(PNG_LIBS) $(JPEG_LIBS) $(TIFF_LIBS)

extras/get_disto.c

@@ -0,0 +1,124 @@
+// Copyright 2016 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.
+// -----------------------------------------------------------------------------
+//
+// Simple tool to load two webp/png/jpg/tiff files and compute PSNR/SSIM.
+// This is mostly a wrapper around WebPPictureDistortion().
+//
+/*
+ gcc -o get_disto get_disto.c -O3 -I../ -L../examples -L../imageio \
+    -lexample_util -limagedec -lwebp -L/opt/local/lib \
+    -lpng -lz -ljpeg -ltiff -lm -lpthread
+*/
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "webp/encode.h"
+#include "../imageio/example_util.h"
+#include "../imageio/image_dec.h"
+
+static size_t ReadPicture(const char* const filename, WebPPicture* const pic,
+                          int keep_alpha) {
+  const uint8_t* data = NULL;
+  size_t data_size = 0;
+  WebPImageReader reader = NULL;
+  int ok = ExUtilReadFile(filename, &data, &data_size);
+  if (!ok) goto Error;
+
+  pic->use_argb = 1;  // force ARGB
+
+  reader = WebPGuessImageReader(data, data_size);
+  ok = (reader != NULL) && reader(data, data_size, pic, keep_alpha, NULL);
+
+ Error:
+  if (!ok) {
+    fprintf(stderr, "Error! Could not process file %s\n", filename);
+  }
+  free((void*)data);
+  return ok ? data_size : 0;
+}
+
+static void Help(void) {
+  fprintf(stderr,
+          "Usage: get_disto [-ssim][-psnr][-alpha] compressed.webp orig.webp\n"
+          "  -ssim ..... print SSIM distortion\n"
+          "  -psnr ..... print PSNR distortion (default)\n"
+          "  -alpha .... preserve alpha plane\n"
+          "  -h ........ this message\n"
+          " Also handles PNG, JPG and TIFF files, in addition to WebP.\n");
+}
+
+int main(int argc, const char *argv[]) {
+  WebPPicture pic1, pic2;
+  int ret = 1;
+  float disto[5];
+  size_t size1 = 0, size2 = 0;
+  int type = 0;
+  int c;
+  int help = 0;
+  int keep_alpha = 0;
+  const char* name1 = NULL;
+  const char* name2 = NULL;
+
+  if (!WebPPictureInit(&pic1) || !WebPPictureInit(&pic2)) {
+    fprintf(stderr, "Can't init pictures\n");
+    return 1;
+  }
+
+  for (c = 1; c < argc; ++c) {
+    if (!strcmp(argv[c], "-ssim")) {
+      type = 1;
+    } else if (!strcmp(argv[c], "-psnr")) {
+      type = 0;
+    } else if (!strcmp(argv[c], "-alpha")) {
+      keep_alpha = 1;
+    } else if (!strcmp(argv[c], "-h")) {
+      help = 1;
+      ret = 0;
+    } else if (name1 == NULL) {
+      name1 = argv[c];
+    } else {
+      name2 = argv[c];
+    }
+  }
+  if (help || name1 == NULL || name2 == NULL) {
+    if (!help) {
+      fprintf(stderr, "Error: missing arguments.\n");
+    }
+    Help();
+    goto End;
+  }
+  if ((size1 = ReadPicture(name1, &pic1, 1)) == 0) {
+    goto End;
+  }
+  if ((size2 = ReadPicture(name2, &pic2, 1)) == 0) {
+    goto End;
+  }
+  if (!keep_alpha) {
+    WebPBlendAlpha(&pic1, 0x00000000);
+    WebPBlendAlpha(&pic2, 0x00000000);
+  }
+
+  if (!WebPPictureDistortion(&pic1, &pic2, type, disto)) {
+    fprintf(stderr, "Error while computing the distortion.\n");
+    goto End;
+  }
+  printf("%u %.2f    %.2f %.2f %.2f %.2f\n",
+         (unsigned int)size1, disto[4],
+         disto[0], disto[1], disto[2], disto[3]);
+  ret = 0;
+
+ End:
+  WebPPictureFree(&pic1);
+  WebPPictureFree(&pic2);
+  return ret;
+}