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// Copyright (c) 2012 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.
// MSVC++ requires this to be set before any other includes to get M_SQRT1_2.
#define _USE_MATH_DEFINES
#include <cmath>
#include "base/stringprintf.h"
#include "media/base/audio_bus.h"
#include "media/base/channel_mixer.h"
#include "testing/gtest/include/gtest/gtest.h"
namespace media {
// Number of frames to test with.
enum { kFrames = 16 };
// Test all possible layout conversions can be constructed and mixed.
TEST(ChannelMixerTest, ConstructAllPossibleLayouts) {
for (ChannelLayout input_layout = CHANNEL_LAYOUT_MONO;
input_layout < CHANNEL_LAYOUT_MAX;
input_layout = static_cast<ChannelLayout>(input_layout + 1)) {
for (ChannelLayout output_layout = CHANNEL_LAYOUT_MONO;
output_layout < CHANNEL_LAYOUT_STEREO_DOWNMIX;
output_layout = static_cast<ChannelLayout>(output_layout + 1)) {
SCOPED_TRACE(base::StringPrintf(
"Input Layout: %d, Output Layout: %d", input_layout, output_layout));
ChannelMixer mixer(input_layout, output_layout);
scoped_ptr<AudioBus> input_bus = AudioBus::Create(
ChannelLayoutToChannelCount(input_layout), kFrames);
scoped_ptr<AudioBus> output_bus = AudioBus::Create(
ChannelLayoutToChannelCount(output_layout), kFrames);
for (int ch = 0; ch < input_bus->channels(); ++ch)
std::fill(input_bus->channel(ch), input_bus->channel(ch) + kFrames, 1);
mixer.Transform(input_bus.get(), output_bus.get());
}
}
}
struct ChannelMixerTestData {
ChannelMixerTestData(ChannelLayout input_layout, ChannelLayout output_layout,
float* channel_values, int num_channel_values,
float scale)
: input_layout(input_layout),
output_layout(output_layout),
channel_values(channel_values),
num_channel_values(num_channel_values),
scale(scale) {
}
std::string DebugString() const {
return base::StringPrintf(
"Input Layout: %d, Output Layout %d, Scale: %f", input_layout,
output_layout, scale);
}
ChannelLayout input_layout;
ChannelLayout output_layout;
float* channel_values;
int num_channel_values;
float scale;
};
std::ostream& operator<<(std::ostream& os, const ChannelMixerTestData& data) {
return os << data.DebugString();
}
class ChannelMixerTest : public testing::TestWithParam<ChannelMixerTestData> {};
// Verify channels are mixed and scaled correctly. The test only works if all
// output channels have the same value.
TEST_P(ChannelMixerTest, Mixing) {
ChannelLayout input_layout = GetParam().input_layout;
ChannelLayout output_layout = GetParam().output_layout;
ChannelMixer mixer(input_layout, output_layout);
scoped_ptr<AudioBus> input_bus = AudioBus::Create(
ChannelLayoutToChannelCount(input_layout), kFrames);
scoped_ptr<AudioBus> output_bus = AudioBus::Create(
ChannelLayoutToChannelCount(output_layout), kFrames);
const float* channel_values = GetParam().channel_values;
ASSERT_EQ(input_bus->channels(), GetParam().num_channel_values);
float expected_value = 0;
float scale = GetParam().scale;
for (int ch = 0; ch < input_bus->channels(); ++ch) {
std::fill(input_bus->channel(ch), input_bus->channel(ch) + kFrames,
channel_values[ch]);
expected_value += channel_values[ch] * scale;
}
mixer.Transform(input_bus.get(), output_bus.get());
for (int ch = 0; ch < output_bus->channels(); ++ch) {
for (int frame = 0; frame < output_bus->frames(); ++frame) {
ASSERT_FLOAT_EQ(output_bus->channel(ch)[frame], expected_value);
}
}
}
static float kStereoToMonoValues[] = { 0.5f, 0.75f };
static float kMonoToStereoValues[] = { 0.5f };
// Zero the center channel since it will be mixed at scale 1 vs M_SQRT1_2.
static float kFiveOneToMonoValues[] = { 0.1f, 0.2f, 0.0f, 0.4f, 0.5f, 0.6f };
// Run through basic sanity tests for some common conversions.
INSTANTIATE_TEST_CASE_P(ChannelMixerTest, ChannelMixerTest, testing::Values(
ChannelMixerTestData(CHANNEL_LAYOUT_STEREO, CHANNEL_LAYOUT_MONO,
kStereoToMonoValues, arraysize(kStereoToMonoValues),
0.5f),
ChannelMixerTestData(CHANNEL_LAYOUT_MONO, CHANNEL_LAYOUT_STEREO,
kMonoToStereoValues, arraysize(kMonoToStereoValues),
1.0f),
ChannelMixerTestData(CHANNEL_LAYOUT_5_1, CHANNEL_LAYOUT_MONO,
kFiveOneToMonoValues, arraysize(kFiveOneToMonoValues),
static_cast<float>(M_SQRT1_2))
));
} // namespace media
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