diff -r 000000000000 -r 6474c204b198 media/libyuv/unit_test/scale_test.cc
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/media/libyuv/unit_test/scale_test.cc	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,188 @@
+/*
+ *  Copyright 2011 The LibYuv Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE 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.
+ */
+
+#include <stdlib.h>
+#include <time.h>
+
+#include "libyuv/cpu_id.h"
+#include "libyuv/scale.h"
+#include "../unit_test/unit_test.h"
+
+namespace libyuv {
+
+// Test scaling with C vs Opt and return maximum pixel difference. 0 = exact.
+static int TestFilter(int src_width, int src_height,
+                      int dst_width, int dst_height,
+                      FilterMode f, int benchmark_iterations) {
+  int i, j;
+  const int b = 128;
+  int src_width_uv = (Abs(src_width) + 1) >> 1;
+  int src_height_uv = (Abs(src_height) + 1) >> 1;
+
+  int src_y_plane_size = (Abs(src_width) + b * 2) * (Abs(src_height) + b * 2);
+  int src_uv_plane_size = (src_width_uv + b * 2) * (src_height_uv + b * 2);
+
+  int src_stride_y = b * 2 + Abs(src_width);
+  int src_stride_uv = b * 2 + src_width_uv;
+
+  align_buffer_page_end(src_y, src_y_plane_size)
+  align_buffer_page_end(src_u, src_uv_plane_size)
+  align_buffer_page_end(src_v, src_uv_plane_size)
+  srandom(time(NULL));
+  MemRandomize(src_y, src_y_plane_size);
+  MemRandomize(src_u, src_uv_plane_size);
+  MemRandomize(src_v, src_uv_plane_size);
+
+  int dst_width_uv = (dst_width + 1) >> 1;
+  int dst_height_uv = (dst_height + 1) >> 1;
+
+  int dst_y_plane_size = (dst_width + b * 2) * (dst_height + b * 2);
+  int dst_uv_plane_size = (dst_width_uv + b * 2) * (dst_height_uv + b * 2);
+
+  int dst_stride_y = b * 2 + dst_width;
+  int dst_stride_uv = b * 2 + dst_width_uv;
+
+  align_buffer_page_end(dst_y_c, dst_y_plane_size)
+  align_buffer_page_end(dst_u_c, dst_uv_plane_size)
+  align_buffer_page_end(dst_v_c, dst_uv_plane_size)
+  align_buffer_page_end(dst_y_opt, dst_y_plane_size)
+  align_buffer_page_end(dst_u_opt, dst_uv_plane_size)
+  align_buffer_page_end(dst_v_opt, dst_uv_plane_size)
+
+
+  MaskCpuFlags(0);  // Disable all CPU optimization.
+  double c_time = get_time();
+  I420Scale(src_y + (src_stride_y * b) + b, src_stride_y,
+            src_u + (src_stride_uv * b) + b, src_stride_uv,
+            src_v + (src_stride_uv * b) + b, src_stride_uv,
+            src_width, src_height,
+            dst_y_c + (dst_stride_y * b) + b, dst_stride_y,
+            dst_u_c + (dst_stride_uv * b) + b, dst_stride_uv,
+            dst_v_c + (dst_stride_uv * b) + b, dst_stride_uv,
+            dst_width, dst_height, f);
+  c_time = (get_time() - c_time);
+
+  MaskCpuFlags(-1);  // Enable all CPU optimization.
+  double opt_time = get_time();
+  for (i = 0; i < benchmark_iterations; ++i) {
+    I420Scale(src_y + (src_stride_y * b) + b, src_stride_y,
+              src_u + (src_stride_uv * b) + b, src_stride_uv,
+              src_v + (src_stride_uv * b) + b, src_stride_uv,
+              src_width, src_height,
+              dst_y_opt + (dst_stride_y * b) + b, dst_stride_y,
+              dst_u_opt + (dst_stride_uv * b) + b, dst_stride_uv,
+              dst_v_opt + (dst_stride_uv * b) + b, dst_stride_uv,
+              dst_width, dst_height, f);
+  }
+  opt_time = (get_time() - opt_time) / benchmark_iterations;
+  // Report performance of C vs OPT
+  printf("filter %d - %8d us C - %8d us OPT\n",
+         f,
+         static_cast<int>(c_time * 1e6),
+         static_cast<int>(opt_time * 1e6));
+
+  // C version may be a little off from the optimized. Order of
+  //  operations may introduce rounding somewhere. So do a difference
+  //  of the buffers and look to see that the max difference isn't
+  //  over 2.
+  int max_diff = 0;
+  for (i = b; i < (dst_height + b); ++i) {
+    for (j = b; j < (dst_width + b); ++j) {
+      int abs_diff = Abs(dst_y_c[(i * dst_stride_y) + j] -
+                         dst_y_opt[(i * dst_stride_y) + j]);
+      if (abs_diff > max_diff) {
+        max_diff = abs_diff;
+      }
+    }
+  }
+
+  for (i = b; i < (dst_height_uv + b); ++i) {
+    for (j = b; j < (dst_width_uv + b); ++j) {
+      int abs_diff = Abs(dst_u_c[(i * dst_stride_uv) + j] -
+                         dst_u_opt[(i * dst_stride_uv) + j]);
+      if (abs_diff > max_diff) {
+        max_diff = abs_diff;
+      }
+      abs_diff = Abs(dst_v_c[(i * dst_stride_uv) + j] -
+                     dst_v_opt[(i * dst_stride_uv) + j]);
+      if (abs_diff > max_diff) {
+        max_diff = abs_diff;
+      }
+    }
+  }
+
+  free_aligned_buffer_page_end(dst_y_c)
+  free_aligned_buffer_page_end(dst_u_c)
+  free_aligned_buffer_page_end(dst_v_c)
+  free_aligned_buffer_page_end(dst_y_opt)
+  free_aligned_buffer_page_end(dst_u_opt)
+  free_aligned_buffer_page_end(dst_v_opt)
+
+  free_aligned_buffer_page_end(src_y)
+  free_aligned_buffer_page_end(src_u)
+  free_aligned_buffer_page_end(src_v)
+
+  return max_diff;
+}
+
+#define TEST_FACTOR1(name, filter, hfactor, vfactor, max_diff)                 \
+    TEST_F(libyuvTest, ScaleDownBy##name##_##filter) {                         \
+      int diff = TestFilter(benchmark_width_, benchmark_height_,               \
+                            Abs(benchmark_width_) * hfactor,                   \
+                            Abs(benchmark_height_) * vfactor,                  \
+                            kFilter##filter, benchmark_iterations_);           \
+      EXPECT_LE(diff, max_diff);                                               \
+    }
+
+// Test a scale factor with all 4 filters.  Expect unfiltered to be exact, but
+// filtering is different fixed point implementations for SSSE3, Neon and C.
+#define TEST_FACTOR(name, hfactor, vfactor)                                    \
+    TEST_FACTOR1(name, None, hfactor, vfactor, 0)                              \
+    TEST_FACTOR1(name, Linear, hfactor, vfactor, 3)                            \
+    TEST_FACTOR1(name, Bilinear, hfactor, vfactor, 3)                          \
+    TEST_FACTOR1(name, Box, hfactor, vfactor, 3)                               \
+
+TEST_FACTOR(2, 1 / 2, 1 / 2)
+TEST_FACTOR(4, 1 / 4, 1 / 4)
+TEST_FACTOR(8, 1 / 8, 1 / 8)
+TEST_FACTOR(3by4, 3 / 4, 3 / 4)
+#undef TEST_FACTOR1
+#undef TEST_FACTOR
+
+#define TEST_SCALETO1(name, width, height, filter, max_diff)                   \
+    TEST_F(libyuvTest, name##To##width##x##height##_##filter) {                \
+      int diff = TestFilter(benchmark_width_, benchmark_height_,               \
+                            width, height,                                     \
+                            kFilter##filter, benchmark_iterations_);           \
+      EXPECT_LE(diff, max_diff);                                               \
+    }                                                                          \
+    TEST_F(libyuvTest, name##From##width##x##height##_##filter) {              \
+      int diff = TestFilter(width, height,                                     \
+                            Abs(benchmark_width_), Abs(benchmark_height_),     \
+                            kFilter##filter, benchmark_iterations_);           \
+      EXPECT_LE(diff, max_diff);                                               \
+    }
+
+// Test scale to a specified size with all 4 filters.
+#define TEST_SCALETO(name, width, height)                                      \
+    TEST_SCALETO1(name, width, height, None, 0)                                \
+    TEST_SCALETO1(name, width, height, Linear, 3)                              \
+    TEST_SCALETO1(name, width, height, Bilinear, 3)                            \
+    TEST_SCALETO1(name, width, height, Box, 3)
+
+TEST_SCALETO(Scale, 1, 1)
+TEST_SCALETO(Scale, 320, 240)
+TEST_SCALETO(Scale, 352, 288)
+TEST_SCALETO(Scale, 640, 360)
+TEST_SCALETO(Scale, 1280, 720)
+#undef TEST_SCALETO1
+#undef TEST_SCALETO
+
+}  // namespace libyuv