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// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <algorithm>
#include <memory>
#include "base/basictypes.h"
#include "base/logging.h"
#include "cobalt/media/base/audio_bus.h"
#include "cobalt/media/base/audio_hash.h"
#include "cobalt/media/base/fake_audio_render_callback.h"
#include "testing/gtest/include/gtest/gtest.h"
namespace cobalt {
namespace media {
static const int kChannelCount = 2;
static const int kFrameCount = 1024;
class AudioHashTest : public testing::Test {
: bus_one_(AudioBus::Create(kChannelCount, kFrameCount)),
bus_two_(AudioBus::Create(kChannelCount, kFrameCount)),
fake_callback_(0.01) {
// Fill each channel in each bus with unique data.
void GenerateUniqueChannels(AudioBus* audio_bus) {
// Use an AudioBus wrapper to avoid an extra memcpy when filling channels.
std::unique_ptr<AudioBus> wrapped_bus = AudioBus::CreateWrapper(1);
// Since FakeAudioRenderCallback generates only a single channel of unique
// audio data, we need to fill each channel manually.
for (int ch = 0; ch < audio_bus->channels(); ++ch) {
wrapped_bus->SetChannelData(0, audio_bus->channel(ch));
fake_callback_.Render(wrapped_bus.get(), 0, 0);
~AudioHashTest() override {}
std::unique_ptr<AudioBus> bus_one_;
std::unique_ptr<AudioBus> bus_two_;
FakeAudioRenderCallback fake_callback_;
// Ensure the same data hashes the same.
TEST_F(AudioHashTest, Equivalence) {
AudioHash hash_one;
hash_one.Update(bus_one_.get(), bus_one_->frames());
AudioHash hash_two;
hash_two.Update(bus_one_.get(), bus_one_->frames());
EXPECT_EQ(hash_one.ToString(), hash_two.ToString());
// Ensure sample order matters to the hash.
TEST_F(AudioHashTest, SampleOrder) {
AudioHash original_hash;
original_hash.Update(bus_one_.get(), bus_one_->frames());
// Swap a sample in the bus.
std::swap(bus_one_->channel(0)[0], bus_one_->channel(0)[1]);
AudioHash swapped_hash;
swapped_hash.Update(bus_one_.get(), bus_one_->frames());
EXPECT_NE(original_hash.ToString(), swapped_hash.ToString());
// Ensure channel order matters to the hash.
TEST_F(AudioHashTest, ChannelOrder) {
AudioHash original_hash;
original_hash.Update(bus_one_.get(), bus_one_->frames());
// Reverse channel order for the same sample data.
const int channels = bus_one_->channels();
std::unique_ptr<AudioBus> swapped_ch_bus = AudioBus::CreateWrapper(channels);
for (int i = channels - 1; i >= 0; --i)
swapped_ch_bus->SetChannelData(channels - (i + 1), bus_one_->channel(i));
AudioHash swapped_hash;
swapped_hash.Update(swapped_ch_bus.get(), swapped_ch_bus->frames());
EXPECT_NE(original_hash.ToString(), swapped_hash.ToString());
// Ensure bus order matters to the hash.
TEST_F(AudioHashTest, BusOrder) {
AudioHash original_hash;
original_hash.Update(bus_one_.get(), bus_one_->frames());
original_hash.Update(bus_two_.get(), bus_two_->frames());
AudioHash reordered_hash;
reordered_hash.Update(bus_two_.get(), bus_two_->frames());
reordered_hash.Update(bus_one_.get(), bus_one_->frames());
EXPECT_NE(original_hash.ToString(), reordered_hash.ToString());
// Ensure bus order matters to the hash even with empty buses.
TEST_F(AudioHashTest, EmptyBusOrder) {
AudioHash one_bus_hash;
one_bus_hash.Update(bus_one_.get(), bus_one_->frames());
AudioHash two_bus_hash;
two_bus_hash.Update(bus_one_.get(), bus_one_->frames());
two_bus_hash.Update(bus_two_.get(), bus_two_->frames());
EXPECT_NE(one_bus_hash.ToString(), two_bus_hash.ToString());
// Where A = [0, n], ensure hash(A[0:n/2]), hash(A[n/2:n]) and hash(A) result
// in the same value.
TEST_F(AudioHashTest, HashIgnoresUpdateOrder) {
AudioHash full_hash;
full_hash.Update(bus_one_.get(), bus_one_->frames());
AudioHash half_hash;
half_hash.Update(bus_one_.get(), bus_one_->frames() / 2);
// Create a new bus representing the second half of |bus_one_|.
const int half_frames = bus_one_->frames() / 2;
const int channels = bus_one_->channels();
std::unique_ptr<AudioBus> half_bus = AudioBus::CreateWrapper(channels);
for (int i = 0; i < channels; ++i)
half_bus->SetChannelData(i, bus_one_->channel(i) + half_frames);
half_hash.Update(half_bus.get(), half_bus->frames());
EXPECT_EQ(full_hash.ToString(), half_hash.ToString());
// Ensure approximate hashes pass verification.
TEST_F(AudioHashTest, VerifySimilarHash) {
AudioHash hash_one;
hash_one.Update(bus_one_.get(), bus_one_->frames());
// Twiddle the values inside the first bus.
float* channel = bus_one_->channel(0);
for (int i = 0; i < bus_one_->frames(); i += bus_one_->frames() / 64)
channel[i] += 0.0001f;
AudioHash hash_two;
hash_two.Update(bus_one_.get(), bus_one_->frames());
EXPECT_EQ(hash_one.ToString(), hash_two.ToString());
// Twiddle the values too much...
for (int i = 0; i < bus_one_->frames(); ++i) channel[i] += 0.0001f;
AudioHash hash_three;
hash_three.Update(bus_one_.get(), bus_one_->frames());
EXPECT_NE(hash_one.ToString(), hash_three.ToString());
} // namespace media
} // namespace cobalt