Expose the internal MatrixBuilder class as ChannelMixingMatrix.

media/base/channel_mixer_unittest.cc

 // 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/strings/stringprintf.h"
 #include "media/audio/audio_parameters.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 <= CHANNEL_LAYOUT_MAX;
          output_layout = static_cast<ChannelLayout>(output_layout + 1)) {
       // DISCRETE can't be tested here based on the current approach.
       // CHANNEL_LAYOUT_STEREO_AND_KEYBOARD_MIC is not mixable.
+      // Stereo down mix should never be the output layout.
       if (input_layout == CHANNEL_LAYOUT_DISCRETE ||
           input_layout == CHANNEL_LAYOUT_STEREO_AND_KEYBOARD_MIC ||
           output_layout == CHANNEL_LAYOUT_DISCRETE ||
-          output_layout == CHANNEL_LAYOUT_STEREO_AND_KEYBOARD_MIC) {
+          output_layout == CHANNEL_LAYOUT_STEREO_AND_KEYBOARD_MIC ||
+          output_layout == CHANNEL_LAYOUT_STEREO_DOWNMIX) {
         continue;
       }
 
       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);
@@ skipping 89 matching lines @@
     expected_value += channel_values[ch] * scale;
   }
 
   ChannelMixer mixer(input_audio, output_audio);
   mixer.Transform(input_bus.get(), output_bus.get());
 
   // Validate the output channel
   if (input_layout != CHANNEL_LAYOUT_DISCRETE) {
     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);
+        ASSERT_FLOAT_EQ(expected_value, output_bus->channel(ch)[frame]);
       }
     }
   } else {
     // Processing discrete mixing. If there is a matching input channel,
     // then the output channel should be set. If no input channel,
     // output channel should be 0
     for (int ch = 0; ch < output_bus->channels(); ++ch) {
       expected_value = (ch < input_channels) ? channel_values[ch] : 0;
       for (int frame = 0; frame < output_bus->frames(); ++frame) {
-        ASSERT_FLOAT_EQ(output_bus->channel(ch)[frame], expected_value);
+        ASSERT_FLOAT_EQ(expected_value, output_bus->channel(ch)[frame]);
       }
     }
   }
 }
 
 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 };
 static float kFiveDiscreteValues[] = { 0.1f, 0.2f, 0.3f, 0.4f, 0.5f };
@@ skipping 14 matching lines @@
                          kStereoToMonoValues, arraysize(kStereoToMonoValues)),
     ChannelMixerTestData(CHANNEL_LAYOUT_DISCRETE, 2,
                          CHANNEL_LAYOUT_DISCRETE, 5,
                          kStereoToMonoValues, arraysize(kStereoToMonoValues)),
     ChannelMixerTestData(CHANNEL_LAYOUT_DISCRETE, 5,
                          CHANNEL_LAYOUT_DISCRETE, 2,
                          kFiveDiscreteValues, arraysize(kFiveDiscreteValues))
 ));
 
 }  // namespace media