Implements RGB to YV12 conversion in YASM.

media/base/simd/convert_rgb_to_yuv_unittest.cc

+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/scoped_ptr.h"
+#include "base/stringprintf.h"
+#include "media/base/cpu_features.h"
+#include "media/base/simd/convert_rgb_to_yuv.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace {
+
+// Reference code that converts RGB pixels to YUV pixels.
+int ConvertRGBToY(const uint8* rgb) {
+  int y = 25 * rgb[0] + 129 * rgb[1] + 66 * rgb[2];
+  y = ((y + 128) >> 8) + 16;
+  return std::max(0, std::min(255, y));
+}
+
+int ConvertRGBToU(const uint8* rgb, int size, bool subsampling) {
+  int u = 0;
+  if (!subsampling) {
+    u = 112 * rgb[0] - 74 * rgb[1] - 38 * rgb[2];
+  } else {
+    int u0 = 112 * rgb[0] - 74 * rgb[1] - 38 * rgb[2];
+    int u1 = 112 * rgb[size] - 74 * rgb[size + 1] - 38 * rgb[size + 2];
+    u = (u0 + u1 + 1) / 2;
+  }
+  u = ((u + 128) >> 8) + 128;
+  return std::max(0, std::min(255, u));
+}
+
+int ConvertRGBToV(const uint8* rgb, int size, bool subsampling) {
+  int v = 0;
+  if (!subsampling) {
+    v = -18 * rgb[0] - 94 * rgb[1] + 112 * rgb[2];
+  } else {
+    int v0 = -18 * rgb[0] - 94 * rgb[1] + 112 * rgb[2];
+    int v1 = -18 * rgb[size] - 94 * rgb[size + 1] + 112 * rgb[size + 2];
+    v = (v0 + v1 + 1) / 2;
+  }
+  v = ((v + 128) >> 8) + 128;
+  return std::max(0, std::min(255, v));
+}
+
+}  // namespace
+
+// A side-by-side test that verifies our ASM functions that convert RGB pixels
+// to YUV pixels can output the expected results. This test converts RGB pixels
+// to YUV pixels with our ASM functions (which use SSE, SSE2, SSE3, and SSSE3)
+// and compare the output YUV pixels with the ones calculated with out reference
+// functions implemented in C++.
+TEST(YUVConvertTest, SideBySideRGB) {
+  // We skip this test on PCs which does not support SSE3 because this test
+  // needs it.
+  if (!media::hasSSSE3())
+    return;
+
+  // This test checks a subset of all RGB values so this test does not take so
+  // long time.
+  const int kStep = 8;
+  const int kWidth = 256 / kStep;
+
+#ifdef ENABLE_SUBSAMPLING
+  const bool kSubsampling = true;
+#else
+  const bool kSubsampling = false;
+#endif
+
+  for (int size = 3; size <= 4; ++size) {
+    // Create the output buffers.
+    scoped_array<uint8> rgb(new uint8[kWidth * size]);
+    scoped_array<uint8> y(new uint8[kWidth]);
+    scoped_array<uint8> u(new uint8[kWidth / 2]);
+    scoped_array<uint8> v(new uint8[kWidth / 2]);
+
+    // Choose the function that converts from RGB pixels to YUV ones.
+    void (*convert)(const uint8*, uint8*, uint8*, uint8*,
+                    int, int, int, int, int) = NULL;
+    if (size == 3)
+      convert = media::ConvertRGB24ToYUV_SSSE3;
+    else
+      convert = media::ConvertRGB32ToYUV_SSSE3;
+
+    for (int r = 0; r < kWidth; ++r) {
+      for (int g = 0; g < kWidth; ++g) {
+
+        // Fill the input pixels.
+        for (int b = 0; b < kWidth; ++b) {
+          rgb[b * size + 0] = b * kStep;
+          rgb[b * size + 1] = g * kStep;
+          rgb[b * size + 2] = r * kStep;
+          if (size == 4)
+            rgb[b * size + 3] = 255;
+        }
+
+        // Convert the input RGB pixels to YUV ones.
+        convert(rgb.get(), y.get(), u.get(), v.get(), kWidth, 1, kWidth * size,
+                kWidth, kWidth / 2);
+
+        // Check the output Y pixels.
+        for (int i = 0; i < kWidth; ++i) {
+          const uint8* p = &rgb[i * size];
+          SCOPED_TRACE(base::StringPrintf("r=%d,g=%d,b=%d", p[2], p[1], p[0]));
+          EXPECT_EQ(ConvertRGBToY(p), y[i]);
+        }
+
+        // Check the output U pixels.
+        for (int i = 0; i < kWidth / 2; ++i) {
+          const uint8* p = &rgb[i * 2 * size];
+          SCOPED_TRACE(base::StringPrintf("r=%d,g=%d,b=%d", p[2], p[1], p[0]));
+          EXPECT_EQ(ConvertRGBToU(p, size, kSubsampling), u[i]);
+        }
+
+        // Check the output V pixels.
+        for (int i = 0; i < kWidth / 2; ++i) {
+          const uint8* p = &rgb[i * 2 * size];
+          SCOPED_TRACE(base::StringPrintf("r=%d,g=%d,b=%d", p[2], p[1], p[0]));
+          EXPECT_EQ(ConvertRGBToV(p, size, kSubsampling), v[i]);
+        }
+      }
+    }
+  }
+}