Port Yaowu's 4x4 fDCT test.

Also fix unit testing.

Change-Id: Iacdc6f1ec53388e093cda1c13e4379e83d4a6535

test/fdct4x4_test.cc

+/*
+ *  Copyright (c) 2012 The WebM 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 <math.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "third_party/googletest/src/include/gtest/gtest.h"
+
+extern "C" {
+#include "vp8/common/idct.h"
+#include "vp8/encoder/dct.h"
+}
+
+#include "vpx/vpx_integer.h"
+
+namespace {
+
+class ACMRandom {
+ public:
+  explicit ACMRandom(int seed) { Reset(seed); }
+
+  void Reset(int seed) { srand(seed); }
+
+  uint8_t Rand8(void) { return (rand() >> 8) & 0xff; }
+
+  int PseudoUniform(int range) { return (rand() >> 8) % range; }
+
+  int operator()(int n) { return PseudoUniform(n); }
+
+  static int DeterministicSeed(void) { return 0xbaba; }
+};
+
+TEST(Vp8FdctTest, SignBiasCheck) {
+  ACMRandom rnd(ACMRandom::DeterministicSeed());
+  int16_t test_input_block[16];
+  int16_t test_output_block[16];
+  const int pitch = 8;
+  int count_sign_block[16][2];
+  const int count_test_block = 1000000;
+
+  memset(count_sign_block, 0, sizeof(count_sign_block));
+
+  for (int i = 0; i < count_test_block; ++i) {
+    // Initialize a test block with input range [-255, 255].
+    for (int j = 0; j < 16; ++j)
+      test_input_block[j] = rnd.Rand8() - rnd.Rand8();
+
+    // TODO(Yaowu): this should be converted to a parameterized test
+    // to test optimized versions of this function.
+    vp8_short_fdct4x4_c(test_input_block, test_output_block, pitch);
+
+    for (int j = 0; j < 16; ++j) {
+      if (test_output_block[j] < 0)
+        ++count_sign_block[j][0];
+      else if (test_output_block[j] > 0)
+        ++count_sign_block[j][1];
+    }
+  }
+
+  for (int j = 0; j < 16; ++j) {
+    const bool bias_acceptable = (abs(count_sign_block[j][0] -
+                                      count_sign_block[j][1]) < 10000);
+    EXPECT_TRUE(bias_acceptable)
+        << "Error: 4x4 FDCT has a sign bias > 1%"
+        << " for input range [-255, 255] at index " << j;
+  }
+
+  memset(count_sign_block, 0, sizeof(count_sign_block));
+
+  for (int i = 0; i < count_test_block; ++i) {
+    // Initialize a test block with input range [-15, 15].
+    for (int j = 0; j < 16; ++j)
+      test_input_block[j] = (rnd.Rand8() >> 4) - (rnd.Rand8() >> 4);
+
+    // TODO(Yaowu): this should be converted to a parameterized test
+    // to test optimized versions of this function.
+    vp8_short_fdct4x4_c(test_input_block, test_output_block, pitch);
+
+    for (int j = 0; j < 16; ++j) {
+      if (test_output_block[j] < 0)
+        ++count_sign_block[j][0];
+      else if (test_output_block[j] > 0)
+        ++count_sign_block[j][1];
+    }
+  }
+
+  for (int j = 0; j < 16; ++j) {
+    const bool bias_acceptable = (abs(count_sign_block[j][0] -
+                                      count_sign_block[j][1]) < 100000);
+    EXPECT_TRUE(bias_acceptable)
+        << "Error: 4x4 FDCT has a sign bias > 10%"
+        << " for input range [-15, 15] at index " << j;
+  }
+};
+
+TEST(Vp8FdctTest, RoundTripErrorCheck) {
+  ACMRandom rnd(ACMRandom::DeterministicSeed());
+  int max_error = 0;
+  double total_error = 0;
+  const int count_test_block = 1000000;
+  for (int i = 0; i < count_test_block; ++i) {
+    int16_t test_input_block[16];
+    int16_t test_temp_block[16];
+    int16_t test_output_block[16];
+
+    // Initialize a test block with input range [-255, 255].
+    for (int j = 0; j < 16; ++j)
+      test_input_block[j] = rnd.Rand8() - rnd.Rand8();
+
+    // TODO(Yaowu): this should be converted to a parameterized test
+    // to test optimized versions of this function.
+    const int pitch = 8;
+    vp8_short_fdct4x4_c(test_input_block, test_temp_block, pitch);
+    // Because the bitstream is not frozen yet, use the idct in the codebase.
+    vp8_short_idct4x4llm_c(test_temp_block, test_output_block, pitch);
+
+    for (int j = 0; j < 16; ++j) {
+      const int diff = test_input_block[j] - test_output_block[j];
+      const int error = diff * diff;
+      if (max_error < error)
+        max_error = error;
+      total_error += error;
+    }
+  }
+
+  EXPECT_GE(1, max_error)
+      << "Error: FDCT/IDCT has an individual roundtrip error > 1";
+
+  EXPECT_GE(count_test_block, total_error)
+      << "Error: FDCT/IDCT has average roundtrip error > 1 per block";
+};
+
+}  // namespace

test/test-data.sha1

+d5dfb0151c9051f8c85999255645d7a23916d3c0  hantro_collage_w352h288.yuv

test/test.mk

 LIBVPX_TEST_SRCS-yes += test.mk
 LIBVPX_TEST_SRCS-yes += boolcoder_test.cc
+LIBVPX_TEST_SRCS-yes += fdct4x4_test.cc
 LIBVPX_TEST_SRCS-yes += test_libvpx.cc
+
+LIBVPX_TEST_DATA-yes += hantro_collage_w352h288.yuv