Merge commit '67653bbe50841153bfeaebcc5792bd8464da9880' as 'external/libwebp/libwebp'

external/libwebp/libwebp/extras/webp_quality.c

@@ -0,0 +1,54 @@
+// Simple tool to roughly evaluate the quality encoding of a webp bitstream
+//
+// Result is a *rough* estimation of the quality. You should just consider
+// the bucket it's in (q > 80? > 50? > 20?) and not take it for face value.
+/*
+ gcc -o webp_quality webp_quality.c -O3 -I../ -L. -L../imageio \
+    -limageio_util -lwebpextras -lwebp -lm -lpthread
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "extras/extras.h"
+#include "imageio/imageio_util.h"
+#include "../examples/unicode.h"
+
+int main(int argc, const char* argv[]) {
+  int c;
+  int quiet = 0;
+  int ok = 1;
+
+  INIT_WARGV(argc, argv);
+
+  for (c = 1; ok && c < argc; ++c) {
+    if (!strcmp(argv[c], "-quiet")) {
+      quiet = 1;
+    } else if (!strcmp(argv[c], "-help") || !strcmp(argv[c], "-h")) {
+      printf("webp_quality [-h][-quiet] webp_files...\n");
+      FREE_WARGV_AND_RETURN(0);
+    } else {
+      const char* const filename = (const char*)GET_WARGV(argv, c);
+      const uint8_t* data = NULL;
+      size_t data_size = 0;
+      int q;
+      ok = ImgIoUtilReadFile(filename, &data, &data_size);
+      if (!ok) break;
+      q = VP8EstimateQuality(data, data_size);
+      if (!quiet) WPRINTF("[%s] ", (const W_CHAR*)filename);
+      if (q < 0) {
+        fprintf(stderr, "Not a WebP file, or not a lossy WebP file.\n");
+        ok = 0;
+      } else {
+        if (!quiet) {
+          printf("Estimated quality factor: %d\n", q);
+        } else {
+          printf("%d\n", q);   // just print the number
+        }
+      }
+      free((void*)data);
+    }
+  }
+  FREE_WARGV_AND_RETURN(ok ? 0 : 1);
+}