diff --git a/test/fdct4x4_test.cc b/test/fdct4x4_test.cc
new file mode 100644
index 0000000000000000000000000000000000000000..a1c31da64403db31fb196c94f9681e1965c3ae76
--- /dev/null
+++ b/test/fdct4x4_test.cc
@@ -0,0 +1,185 @@
+/*
+* 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 <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+
+
+extern "C" {
+#include "vpx_rtcd.h"
+}
+
+#include "third_party/googletest/src/include/gtest/gtest.h"
+#include "vpx/vpx_integer.h"
+#include "vpx_mem/vpx_mem.h"
+#include "vp8/encoder/onyx_int.h"
+
+
+namespace {
+
+const int cospi8sqrt2minus1 = 20091;
+const int sinpi8sqrt2 = 35468;
+
+void reference_idct4x4(const int16_t *input, int16_t *output) {
+ const int16_t *ip = input;
+ int16_t *op = output;
+
+ for (int i = 0; i < 4; ++i) {
+ const int a1 = ip[0] + ip[8];
+ const int b1 = ip[0] - ip[8];
+ const int temp1 = (ip[4] * sinpi8sqrt2) >> 16;
+ const int temp2 = ip[12] + ((ip[12] * cospi8sqrt2minus1) >> 16);
+ const int c1 = temp1 - temp2;
+ const int temp3 = ip[4] + ((ip[4] * cospi8sqrt2minus1) >> 16);
+ const int temp4 = (ip[12] * sinpi8sqrt2) >> 16;
+ const int d1 = temp3 + temp4;
+ op[0] = a1 + d1;
+ op[12] = a1 - d1;
+ op[4] = b1 + c1;
+ op[8] = b1 - c1;
+ ++ip;
+ ++op;
+ }
+ ip = output;
+ op = output;
+ for (int i = 0; i < 4; ++i) {
+ const int a1 = ip[0] + ip[2];
+ const int b1 = ip[0] - ip[2];
+ const int temp1 = (ip[1] * sinpi8sqrt2) >> 16;
+ const int temp2 = ip[3] + ((ip[3] * cospi8sqrt2minus1) >> 16);
+ const int c1 = temp1 - temp2;
+ const int temp3 = ip[1] + ((ip[1] * cospi8sqrt2minus1) >> 16);
+ const int temp4 = (ip[3] * sinpi8sqrt2) >> 16;
+ const int d1 = temp3 + temp4;
+ op[0] = (a1 + d1 + 4) >> 3;
+ op[3] = (a1 - d1 + 4) >> 3;
+ op[1] = (b1 + c1 + 4) >> 3;
+ op[2] = (b1 - c1 + 4) >> 3;
+ ip += 4;
+ op += 4;
+ }
+}
+
+// This is a class that generate random numbers for test input.
+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();
+
+ 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];
+ }
+ }
+
+ bool bias_acceptable = true;
+ for (int j = 0; j < 16; ++j)
+ bias_acceptable = bias_acceptable &&
+ (abs(count_sign_block[j][0] - count_sign_block[j][1]) < 10000);
+
+ EXPECT_EQ(true, bias_acceptable)
+ << "Error: 4x4 FDCT has a sign bias > 1% for input range [-255, 255]";
+
+ 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);
+
+ 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];
+ }
+ }
+
+ bias_acceptable = true;
+ for (int j = 0; j < 16; ++j)
+ bias_acceptable = bias_acceptable &&
+ (abs(count_sign_block[j][0] - count_sign_block[j][1]) < 100000);
+
+ EXPECT_EQ(true, bias_acceptable)
+ << "Error: 4x4 FDCT has a sign bias > 10% for input range [-15, 15]";
+};
+
+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();
+
+ const int pitch = 8;
+ vp8_short_fdct4x4_c(test_input_block, test_temp_block, pitch);
+ reference_idct4x4(test_temp_block, test_output_block);
+
+ 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
diff --git a/test/test.mk b/test/test.mk
index 20bcdc42a63918422b57d2b25ae8ed4132354f65..ae5016c77566767834d1fe1dfd932ac5573bf262 100644
--- a/test/test.mk
+++ b/test/test.mk
@@ -6,6 +6,7 @@ LIBVPX_TEST_SRCS-yes += encode_test_driver.h
LIBVPX_TEST_SRCS-yes += i420_video_source.h
LIBVPX_TEST_SRCS-yes += idctllm_test.cc
LIBVPX_TEST_SRCS-yes += intrapred_test.cc
+LIBVPX_TEST_SRCS-yes += fdct4x4_test.cc
LIBVPX_TEST_SRCS-yes += keyframe_test.cc
LIBVPX_TEST_SRCS-yes += pp_filter_test.cc
LIBVPX_TEST_SRCS-yes += resize_test.cc