libvpx: Add VP9 decoder.

source/libvpx/test/idct8x8_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 "vp9_rtcd.h"
+}
+
+#include "acm_random.h"
+#include "vpx/vpx_integer.h"
+
+using libvpx_test::ACMRandom;
+
+namespace {
+
+#ifdef _MSC_VER
+static int round(double x) {
+  if(x < 0)
+    return (int)ceil(x - 0.5);
+  else
+    return (int)floor(x + 0.5);
+}
+#endif
+
+void reference_dct_1d(double input[8], double output[8]) {
+  const double kPi = 3.141592653589793238462643383279502884;
+  const double kInvSqrt2 = 0.707106781186547524400844362104;
+  for (int k = 0; k < 8; k++) {
+    output[k] = 0.0;
+    for (int n = 0; n < 8; n++)
+      output[k] += input[n]*cos(kPi*(2*n+1)*k/16.0);
+    if (k == 0)
+      output[k] = output[k]*kInvSqrt2;
+  }
+}
+
+void reference_dct_2d(int16_t input[64], double output[64]) {
+  // First transform columns
+  for (int i = 0; i < 8; ++i) {
+    double temp_in[8], temp_out[8];
+    for (int j = 0; j < 8; ++j)
+      temp_in[j] = input[j*8 + i];
+    reference_dct_1d(temp_in, temp_out);
+    for (int j = 0; j < 8; ++j)
+      output[j*8 + i] = temp_out[j];
+  }
+  // Then transform rows
+  for (int i = 0; i < 8; ++i) {
+    double temp_in[8], temp_out[8];
+    for (int j = 0; j < 8; ++j)
+      temp_in[j] = output[j + i*8];
+    reference_dct_1d(temp_in, temp_out);
+    for (int j = 0; j < 8; ++j)
+      output[j + i*8] = temp_out[j];
+  }
+  // Scale by some magic number
+  for (int i = 0; i < 64; ++i)
+    output[i] *= 2;
+}
+
+void reference_idct_1d(double input[8], double output[8]) {
+  const double kPi = 3.141592653589793238462643383279502884;
+  const double kSqrt2 = 1.414213562373095048801688724209698;
+  for (int k = 0; k < 8; k++) {
+    output[k] = 0.0;
+    for (int n = 0; n < 8; n++) {
+      output[k] += input[n]*cos(kPi*(2*k+1)*n/16.0);
+      if (n == 0)
+        output[k] = output[k]/kSqrt2;
+    }
+  }
+}
+
+void reference_idct_2d(double input[64], int16_t output[64]) {
+  double out[64], out2[64];
+  // First transform rows
+  for (int i = 0; i < 8; ++i) {
+    double temp_in[8], temp_out[8];
+    for (int j = 0; j < 8; ++j)
+      temp_in[j] = input[j + i*8];
+    reference_idct_1d(temp_in, temp_out);
+    for (int j = 0; j < 8; ++j)
+      out[j + i*8] = temp_out[j];
+  }
+  // Then transform columns
+  for (int i = 0; i < 8; ++i) {
+    double temp_in[8], temp_out[8];
+    for (int j = 0; j < 8; ++j)
+      temp_in[j] = out[j*8 + i];
+    reference_idct_1d(temp_in, temp_out);
+    for (int j = 0; j < 8; ++j)
+      out2[j*8 + i] = temp_out[j];
+  }
+  for (int i = 0; i < 64; ++i)
+    output[i] = round(out2[i]/32);
+}
+
+TEST(VP9Idct8x8Test, AccuracyCheck) {
+  ACMRandom rnd(ACMRandom::DeterministicSeed());
+  const int count_test_block = 10000;
+  for (int i = 0; i < count_test_block; ++i) {
+    int16_t input[64], coeff[64];
+    int16_t output_c[64];
+    double output_r[64];
+
+    // Initialize a test block with input range [-255, 255].
+    for (int j = 0; j < 64; ++j)
+      input[j] = rnd.Rand8() - rnd.Rand8();
+
+    const int pitch = 16;
+    vp9_short_fdct8x8_c(input, output_c, pitch);
+    reference_dct_2d(input, output_r);
+
+    for (int j = 0; j < 64; ++j) {
+      const double diff = output_c[j] - output_r[j];
+      const double error = diff * diff;
+      // An error in a DCT coefficient isn't that bad.
+      // We care more about the reconstructed pixels.
+      EXPECT_GE(2.0, error)
+          << "Error: 8x8 FDCT/IDCT has error " << error
+          << " at index " << j;
+    }
+
+#if 0
+    // Tests that the reference iDCT and fDCT match.
+    reference_dct_2d(input, output_r);
+    reference_idct_2d(output_r, output_c);
+    for (int j = 0; j < 64; ++j) {
+      const int diff = output_c[j] -input[j];
+      const int error = diff * diff;
+      EXPECT_EQ(0, error)
+          << "Error: 8x8 FDCT/IDCT has error " << error
+          << " at index " << j;
+    }
+#endif
+    reference_dct_2d(input, output_r);
+    for (int j = 0; j < 64; ++j)
+      coeff[j] = round(output_r[j]);
+    vp9_short_idct8x8_c(coeff, output_c, pitch);
+    for (int j = 0; j < 64; ++j) {
+      const int diff = output_c[j] -input[j];
+      const int error = diff * diff;
+      EXPECT_GE(1, error)
+          << "Error: 8x8 FDCT/IDCT has error " << error
+          << " at index " << j;
+    }
+  }
+}
+
+}  // namespace