media/base/channel_mixer_unittest.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 // MSVC++ requires this to be set before any other includes to get M_SQRT1_2.
   6 #define _USE_MATH_DEFINES
   7
   8 #include <cmath>
   9
  10 #include "base/strings/stringprintf.h"
  11 #include "media/audio/audio_parameters.h"
  12 #include "media/base/audio_bus.h"
  13 #include "media/base/channel_mixer.h"
  14 #include "testing/gtest/include/gtest/gtest.h"
  15
  16 namespace media {
  17
  18 // Number of frames to test with.
  19 enum { kFrames = 16 };
  20
  21 // Test all possible layout conversions can be constructed and mixed.
  22 TEST(ChannelMixerTest, ConstructAllPossibleLayouts) {
  23   for (ChannelLayout input_layout = CHANNEL_LAYOUT_MONO;
  24        input_layout < CHANNEL_LAYOUT_MAX;
  25        input_layout = static_cast<ChannelLayout>(input_layout + 1)) {
  26     for (ChannelLayout output_layout = CHANNEL_LAYOUT_MONO;
  27          output_layout < CHANNEL_LAYOUT_STEREO_DOWNMIX;
  28          output_layout = static_cast<ChannelLayout>(output_layout + 1)) {
  29       // DISCRETE can't be tested here based on the current approach.
  30       if (input_layout == CHANNEL_LAYOUT_DISCRETE ||
  31           output_layout == CHANNEL_LAYOUT_DISCRETE)
  32         continue;
  33
  34       SCOPED_TRACE(base::StringPrintf(
  35           "Input Layout: %d, Output Layout: %d", input_layout, output_layout));
  36       ChannelMixer mixer(input_layout, output_layout);
  37       scoped_ptr<AudioBus> input_bus = AudioBus::Create(
  38           ChannelLayoutToChannelCount(input_layout), kFrames);
  39       scoped_ptr<AudioBus> output_bus = AudioBus::Create(
  40           ChannelLayoutToChannelCount(output_layout), kFrames);
  41       for (int ch = 0; ch < input_bus->channels(); ++ch)
  42         std::fill(input_bus->channel(ch), input_bus->channel(ch) + kFrames, 1);
  43
  44       mixer.Transform(input_bus.get(), output_bus.get());
  45     }
  46   }
  47 }
  48
  49 struct ChannelMixerTestData {
  50   ChannelMixerTestData(ChannelLayout input_layout, ChannelLayout output_layout,
  51                        float* channel_values, int num_channel_values,
  52                        float scale)
  53       : input_layout(input_layout),
  54         output_layout(output_layout),
  55         channel_values(channel_values),
  56         num_channel_values(num_channel_values),
  57         scale(scale) {
  58     input_channels = ChannelLayoutToChannelCount(input_layout);
  59     output_channels = ChannelLayoutToChannelCount(output_layout);
  60   }
  61
  62   ChannelMixerTestData(ChannelLayout input_layout, int input_channels,
  63                        ChannelLayout output_layout, int output_channels,
  64                        float* channel_values, int num_channel_values)
  65       : input_layout(input_layout),
  66         input_channels(input_channels),
  67         output_layout(output_layout),
  68         output_channels(output_channels),
  69         channel_values(channel_values),
  70         num_channel_values(num_channel_values),
  71         scale(1.0f) {
  72   }
  73
  74   std::string DebugString() const {
  75     return base::StringPrintf(
  76         "Input Layout: %d, Output Layout %d, Scale: %f", input_layout,
  77         output_layout, scale);
  78   }
  79
  80   ChannelLayout input_layout;
  81   int input_channels;
  82   ChannelLayout output_layout;
  83   int output_channels;
  84   float* channel_values;
  85   int num_channel_values;
  86   float scale;
  87 };
  88
  89 std::ostream& operator<<(std::ostream& os, const ChannelMixerTestData& data) {
  90   return os << data.DebugString();
  91 }
  92
  93 class ChannelMixerTest : public testing::TestWithParam<ChannelMixerTestData> {};
  94
  95 // Verify channels are mixed and scaled correctly.  The test only works if all
  96 // output channels have the same value.
  97 TEST_P(ChannelMixerTest, Mixing) {
  98   ChannelLayout input_layout = GetParam().input_layout;
  99   int input_channels = GetParam().input_channels;
 100   scoped_ptr<AudioBus> input_bus = AudioBus::Create(input_channels, kFrames);
 101   AudioParameters input_audio(AudioParameters::AUDIO_PCM_LINEAR,
 102                               input_layout,
 103                               AudioParameters::kAudioCDSampleRate, 16,
 104                               kFrames);
 105   if (input_layout == CHANNEL_LAYOUT_DISCRETE)
 106     input_audio.SetDiscreteChannels(input_channels);
 107
 108   ChannelLayout output_layout = GetParam().output_layout;
 109   int output_channels = GetParam().output_channels;
 110   scoped_ptr<AudioBus> output_bus = AudioBus::Create(output_channels, kFrames);
 111   AudioParameters output_audio(AudioParameters::AUDIO_PCM_LINEAR,
 112                                output_layout,
 113                                AudioParameters::kAudioCDSampleRate, 16,
 114                                kFrames);
 115   if (output_layout == CHANNEL_LAYOUT_DISCRETE)
 116     output_audio.SetDiscreteChannels(output_channels);
 117
 118   const float* channel_values = GetParam().channel_values;
 119   ASSERT_EQ(input_bus->channels(), GetParam().num_channel_values);
 120
 121   float expected_value = 0;
 122   float scale = GetParam().scale;
 123   for (int ch = 0; ch < input_bus->channels(); ++ch) {
 124     std::fill(input_bus->channel(ch), input_bus->channel(ch) + kFrames,
 125               channel_values[ch]);
 126     expected_value += channel_values[ch] * scale;
 127   }
 128
 129   ChannelMixer mixer(input_audio, output_audio);
 130   mixer.Transform(input_bus.get(), output_bus.get());
 131
 132   // Validate the output channel
 133   if (input_layout != CHANNEL_LAYOUT_DISCRETE) {
 134     for (int ch = 0; ch < output_bus->channels(); ++ch) {
 135       for (int frame = 0; frame < output_bus->frames(); ++frame) {
 136         ASSERT_FLOAT_EQ(output_bus->channel(ch)[frame], expected_value);
 137       }
 138     }
 139   } else {
 140     // Processing discrete mixing. If there is a matching input channel,
 141     // then the output channel should be set. If no input channel,
 142     // output channel should be 0
 143     for (int ch = 0; ch < output_bus->channels(); ++ch) {
 144       expected_value = (ch < input_channels) ? channel_values[ch] : 0;
 145       for (int frame = 0; frame < output_bus->frames(); ++frame) {
 146         ASSERT_FLOAT_EQ(output_bus->channel(ch)[frame], expected_value);
 147       }
 148     }
 149   }
 150 }
 151
 152 static float kStereoToMonoValues[] = { 0.5f, 0.75f };
 153 static float kMonoToStereoValues[] = { 0.5f };
 154 // Zero the center channel since it will be mixed at scale 1 vs M_SQRT1_2.
 155 static float kFiveOneToMonoValues[] = { 0.1f, 0.2f, 0.0f, 0.4f, 0.5f, 0.6f };
 156 static float kFiveDiscreteValues[] = { 0.1f, 0.2f, 0.3f, 0.4f, 0.5f };
 157
 158 // Run through basic sanity tests for some common conversions.
 159 INSTANTIATE_TEST_CASE_P(ChannelMixerTest, ChannelMixerTest, testing::Values(
 160     ChannelMixerTestData(CHANNEL_LAYOUT_STEREO, CHANNEL_LAYOUT_MONO,
 161                          kStereoToMonoValues, arraysize(kStereoToMonoValues),
 162                          0.5f),
 163     ChannelMixerTestData(CHANNEL_LAYOUT_MONO, CHANNEL_LAYOUT_STEREO,
 164                          kMonoToStereoValues, arraysize(kMonoToStereoValues),
 165                          1.0f),
 166     ChannelMixerTestData(CHANNEL_LAYOUT_5_1, CHANNEL_LAYOUT_MONO,
 167                          kFiveOneToMonoValues, arraysize(kFiveOneToMonoValues),
 168                          static_cast<float>(M_SQRT1_2)),
 169     ChannelMixerTestData(CHANNEL_LAYOUT_DISCRETE, 2,
 170                          CHANNEL_LAYOUT_DISCRETE, 2,
 171                          kStereoToMonoValues, arraysize(kStereoToMonoValues)),
 172     ChannelMixerTestData(CHANNEL_LAYOUT_DISCRETE, 2,
 173                          CHANNEL_LAYOUT_DISCRETE, 5,
 174                          kStereoToMonoValues, arraysize(kStereoToMonoValues)),
 175     ChannelMixerTestData(CHANNEL_LAYOUT_DISCRETE, 5,
 176                          CHANNEL_LAYOUT_DISCRETE, 2,
 177                          kFiveDiscreteValues, arraysize(kFiveDiscreteValues))
 178 ));
 179
 180 }  // namespace media