Implements RGB to YV12 conversion in YASM.

media/base/yuv_convert_unittest.cc

Index: media/base/yuv_convert_unittest.cc
===================================================================
--- media/base/yuv_convert_unittest.cc	(revision 99154)
+++ media/base/yuv_convert_unittest.cc	(working copy)
@@ -6,11 +6,68 @@
 #include "base/file_util.h"
 #include "base/logging.h"
 #include "base/path_service.h"
+#include "base/stringprintf.h"
 #include "media/base/djb2.h"
 #include "media/base/yuv_convert.h"
 #include "media/base/yuv_row.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));
+}
+
+// Reference code that converts YUV pixels to RGB pixels.
+int ConvertYUVToR(uint8 y, uint8 u, uint8 v) {
+  int r = 298 * (y - 16) + 409 * (v - 128);
+  r = (r + 128) >> 8;
+  return std::max(0, std::min(255, r));
+}
+
+int ConvertYUVToG(uint8 y, uint8 u, uint8 v) {
+  int g = 298 * (y - 16) - 100 * (u - 128) - 208 * (v - 128);
+  g = (g + 128) >> 8;
+  return std::max(0, std::min(255, g));
+}
+
+int ConvertYUVToB(uint8 y, uint8 u, uint8 v) {
+  int b = 298 * (y - 16) + 516 * (u - 128);
+  b = (b + 128) >> 8;
+  return std::max(0, std::min(255, b));
+}
+
+}  // namespace
+
 // Size of raw image.
 static const int kSourceWidth = 640;
 static const int kSourceHeight = 360;
@@ -294,3 +351,115 @@
                              kDJB2HashSeed);
   EXPECT_EQ(666823187u, yuy_hash);
 }
+
+// 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) {

[Alpha Left Google, 2011/09/01 13:26:41]

One more comment on these tests, since they test ConvertRGB32ToYUV which can be
implemented differently under the hood, it's better to test the SSSE3 version
here. I suggest you move this test to be under media/base/simd.

+  // 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;
+    else
+      convert = media::ConvertRGB32ToYUV;
+
+    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]);
+        }
+      }
+    }
+  }
+}
+
+// Another side-by-side test for our ASM functions that convert YUV pixels
+// to RGB pixels.
+TEST(YUVConvertTest, SideBySideYUV) {
+  const int kStep = 4;
+  const int kWidth = 256 / kStep;
+
+  // Create the output buffers.
+  scoped_array<uint8> rgb(new uint8[kWidth * 4]);
+  scoped_array<uint8> y(new uint8[kWidth]);
+  scoped_array<uint8> u(new uint8[kWidth / 2]);
+  scoped_array<uint8> v(new uint8[kWidth / 2]);
+
+  for (int y0 = 0; y0 < kWidth; ++y0) {
+    for (int i = 0; i < kWidth; ++i)
+      y[i] = y0 * kStep;
+
+    for (int u0 = 0; u0 < kWidth / 2; ++u0) {
+      for (int i = 0; i < kWidth / 2; ++i)
+        u[i] = u0 * kStep * 2;
+
+      for (int v0 = 0; v0 < kWidth / 2; ++v0)
+        v[v0] = v0 * kStep * 2;
+
+      // Convert the input YUV pixels to RGB ones.
+      media::ConvertYUVToRGB32(y.get(), u.get(), v.get(), rgb.get(), kWidth, 1,
+                               kWidth, kWidth / 2, kWidth * 4, media::YV12);
+
+      for (int i = 0; i < kWidth; ++i) {
+        SCOPED_TRACE(
+            base::StringPrintf("y=%d,u=%d,v=%d", y[i], u[i / 2], v[i / 2]));
+        EXPECT_EQ(255, rgb[i * 4 + 3]);
+        EXPECT_EQ(ConvertYUVToR(y[i], u[i / 2], v[i / 2]), rgb[i * 4 + 2]);
+        EXPECT_EQ(ConvertYUVToG(y[i], u[i / 2], v[i / 2]), rgb[i * 4 + 1]);
+        EXPECT_EQ(ConvertYUVToB(y[i], u[i / 2], v[i / 2]), rgb[i * 4 + 0]);
+      }
+    }
+  }
+}