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/*
* 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 {
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
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