Index: media/base/channel_mixer.cc |
diff --git a/media/base/channel_mixer.cc b/media/base/channel_mixer.cc |
index ef1bd5c096e96421f2fc6c02fce1ea3a3f57fa42..54b59a891794942c6b494265a2aa36bce59806ff 100644 |
--- a/media/base/channel_mixer.cc |
+++ b/media/base/channel_mixer.cc |
@@ -2,114 +2,16 @@ |
// 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 "media/base/channel_mixer.h" |
-#include <algorithm> |
-#include <cmath> |
- |
#include "base/logging.h" |
#include "media/audio/audio_parameters.h" |
#include "media/base/audio_bus.h" |
+#include "media/base/channel_mixing_matrix.h" |
#include "media/base/vector_math.h" |
namespace media { |
-// Default scale factor for mixing two channels together. We use a different |
-// value for stereo -> mono and mono -> stereo mixes. |
-static const float kEqualPowerScale = static_cast<float>(M_SQRT1_2); |
- |
-static void ValidateLayout(ChannelLayout layout) { |
- CHECK_NE(layout, CHANNEL_LAYOUT_NONE); |
- CHECK_LE(layout, CHANNEL_LAYOUT_MAX); |
- CHECK_NE(layout, CHANNEL_LAYOUT_UNSUPPORTED); |
- CHECK_NE(layout, CHANNEL_LAYOUT_DISCRETE); |
- CHECK_NE(layout, CHANNEL_LAYOUT_STEREO_AND_KEYBOARD_MIC); |
- |
- // Verify there's at least one channel. Should always be true here by virtue |
- // of not being one of the invalid layouts, but lets double check to be sure. |
- int channel_count = ChannelLayoutToChannelCount(layout); |
- DCHECK_GT(channel_count, 0); |
- |
- // If we have more than one channel, verify a symmetric layout for sanity. |
- // The unit test will verify all possible layouts, so this can be a DCHECK. |
- // Symmetry allows simplifying the matrix building code by allowing us to |
- // assume that if one channel of a pair exists, the other will too. |
- if (channel_count > 1) { |
- // Assert that LEFT exists if and only if RIGHT exists, and so on. |
- DCHECK_EQ(ChannelOrder(layout, LEFT) >= 0, |
- ChannelOrder(layout, RIGHT) >= 0); |
- DCHECK_EQ(ChannelOrder(layout, SIDE_LEFT) >= 0, |
- ChannelOrder(layout, SIDE_RIGHT) >= 0); |
- DCHECK_EQ(ChannelOrder(layout, BACK_LEFT) >= 0, |
- ChannelOrder(layout, BACK_RIGHT) >= 0); |
- DCHECK_EQ(ChannelOrder(layout, LEFT_OF_CENTER) >= 0, |
- ChannelOrder(layout, RIGHT_OF_CENTER) >= 0); |
- } else { |
- DCHECK_EQ(layout, CHANNEL_LAYOUT_MONO); |
- } |
-} |
- |
-class MatrixBuilder { |
- public: |
- MatrixBuilder(ChannelLayout input_layout, int input_channels, |
- ChannelLayout output_layout, int output_channels) |
- : input_layout_(input_layout), |
- input_channels_(input_channels), |
- output_layout_(output_layout), |
- output_channels_(output_channels) { |
- // Special case for 5.0, 5.1 with back channels when upmixed to 7.0, 7.1, |
- // which should map the back LR to side LR. |
- if (input_layout_ == CHANNEL_LAYOUT_5_0_BACK && |
- output_layout_ == CHANNEL_LAYOUT_7_0) { |
- input_layout_ = CHANNEL_LAYOUT_5_0; |
- } else if (input_layout_ == CHANNEL_LAYOUT_5_1_BACK && |
- output_layout_ == CHANNEL_LAYOUT_7_1) { |
- input_layout_ = CHANNEL_LAYOUT_5_1; |
- } |
- } |
- |
- ~MatrixBuilder() { } |
- |
- // Create the transformation matrix of input channels to output channels. |
- // Updates the empty matrix with the transformation, and returns true |
- // if the transformation is just a remapping of channels (no mixing). |
- bool CreateTransformationMatrix(std::vector< std::vector<float> >* matrix); |
- |
- private: |
- // Result transformation of input channels to output channels |
- std::vector< std::vector<float> >* matrix_; |
- |
- // Input and output channel layout provided during construction. |
- ChannelLayout input_layout_; |
- int input_channels_; |
- ChannelLayout output_layout_; |
- int output_channels_; |
- |
- // Helper variable for tracking which inputs are currently unaccounted, |
- // should be empty after construction completes. |
- std::vector<Channels> unaccounted_inputs_; |
- |
- // Helper methods for managing unaccounted input channels. |
- void AccountFor(Channels ch); |
- bool IsUnaccounted(Channels ch) const; |
- |
- // Helper methods for checking if |ch| exists in either |input_layout_| or |
- // |output_layout_| respectively. |
- bool HasInputChannel(Channels ch) const; |
- bool HasOutputChannel(Channels ch) const; |
- |
- // Helper methods for updating |matrix_| with the proper value for |
- // mixing |input_ch| into |output_ch|. MixWithoutAccounting() does not |
- // remove the channel from |unaccounted_inputs_|. |
- void Mix(Channels input_ch, Channels output_ch, float scale); |
- void MixWithoutAccounting(Channels input_ch, Channels output_ch, float scale); |
- |
- DISALLOW_COPY_AND_ASSIGN(MatrixBuilder); |
-}; |
- |
ChannelMixer::ChannelMixer(ChannelLayout input_layout, |
ChannelLayout output_layout) { |
Initialize(input_layout, |
@@ -129,203 +31,12 @@ ChannelMixer::ChannelMixer( |
void ChannelMixer::Initialize( |
ChannelLayout input_layout, int input_channels, |
ChannelLayout output_layout, int output_channels) { |
- // Stereo down mix should never be the output layout. |
- CHECK_NE(output_layout, CHANNEL_LAYOUT_STEREO_DOWNMIX); |
- |
- // Verify that the layouts are supported |
- if (input_layout != CHANNEL_LAYOUT_DISCRETE) |
- ValidateLayout(input_layout); |
- if (output_layout != CHANNEL_LAYOUT_DISCRETE) |
- ValidateLayout(output_layout); |
- |
// Create the transformation matrix |
- MatrixBuilder matrix_builder(input_layout, input_channels, |
- output_layout, output_channels); |
+ ChannelMixingMatrix matrix_builder(input_layout, input_channels, |
+ output_layout, output_channels); |
remapping_ = matrix_builder.CreateTransformationMatrix(&matrix_); |
} |
-bool MatrixBuilder::CreateTransformationMatrix( |
- std::vector< std::vector<float> >* matrix) { |
- matrix_ = matrix; |
- |
- // Size out the initial matrix. |
- matrix_->reserve(output_channels_); |
- for (int output_ch = 0; output_ch < output_channels_; ++output_ch) |
- matrix_->push_back(std::vector<float>(input_channels_, 0)); |
- |
- // First check for discrete case. |
- if (input_layout_ == CHANNEL_LAYOUT_DISCRETE || |
- output_layout_ == CHANNEL_LAYOUT_DISCRETE) { |
- // If the number of input channels is more than output channels, then |
- // copy as many as we can then drop the remaining input channels. |
- // If the number of input channels is less than output channels, then |
- // copy them all, then zero out the remaining output channels. |
- int passthrough_channels = std::min(input_channels_, output_channels_); |
- for (int i = 0; i < passthrough_channels; ++i) |
- (*matrix_)[i][i] = 1; |
- |
- return true; |
- } |
- |
- // Route matching channels and figure out which ones aren't accounted for. |
- for (Channels ch = LEFT; ch < CHANNELS_MAX + 1; |
- ch = static_cast<Channels>(ch + 1)) { |
- int input_ch_index = ChannelOrder(input_layout_, ch); |
- if (input_ch_index < 0) |
- continue; |
- |
- int output_ch_index = ChannelOrder(output_layout_, ch); |
- if (output_ch_index < 0) { |
- unaccounted_inputs_.push_back(ch); |
- continue; |
- } |
- |
- DCHECK_LT(static_cast<size_t>(output_ch_index), matrix_->size()); |
- DCHECK_LT(static_cast<size_t>(input_ch_index), |
- (*matrix_)[output_ch_index].size()); |
- (*matrix_)[output_ch_index][input_ch_index] = 1; |
- } |
- |
- // If all input channels are accounted for, there's nothing left to do. |
- if (unaccounted_inputs_.empty()) { |
- // Since all output channels map directly to inputs we can optimize. |
- return true; |
- } |
- |
- // Mix front LR into center. |
- if (IsUnaccounted(LEFT)) { |
- // When down mixing to mono from stereo, we need to be careful of full scale |
- // stereo mixes. Scaling by 1 / sqrt(2) here will likely lead to clipping |
- // so we use 1 / 2 instead. |
- float scale = |
- (output_layout_ == CHANNEL_LAYOUT_MONO && input_channels_ == 2) ? |
- 0.5 : kEqualPowerScale; |
- Mix(LEFT, CENTER, scale); |
- Mix(RIGHT, CENTER, scale); |
- } |
- |
- // Mix center into front LR. |
- if (IsUnaccounted(CENTER)) { |
- // When up mixing from mono, just do a copy to front LR. |
- float scale = |
- (input_layout_ == CHANNEL_LAYOUT_MONO) ? 1 : kEqualPowerScale; |
- MixWithoutAccounting(CENTER, LEFT, scale); |
- Mix(CENTER, RIGHT, scale); |
- } |
- |
- // Mix back LR into: side LR || back center || front LR || front center. |
- if (IsUnaccounted(BACK_LEFT)) { |
- if (HasOutputChannel(SIDE_LEFT)) { |
- // If the input has side LR, mix back LR into side LR, but instead if the |
- // input doesn't have side LR (but output does) copy back LR to side LR. |
- float scale = HasInputChannel(SIDE_LEFT) ? kEqualPowerScale : 1; |
- Mix(BACK_LEFT, SIDE_LEFT, scale); |
- Mix(BACK_RIGHT, SIDE_RIGHT, scale); |
- } else if (HasOutputChannel(BACK_CENTER)) { |
- // Mix back LR into back center. |
- Mix(BACK_LEFT, BACK_CENTER, kEqualPowerScale); |
- Mix(BACK_RIGHT, BACK_CENTER, kEqualPowerScale); |
- } else if (output_layout_ > CHANNEL_LAYOUT_MONO) { |
- // Mix back LR into front LR. |
- Mix(BACK_LEFT, LEFT, kEqualPowerScale); |
- Mix(BACK_RIGHT, RIGHT, kEqualPowerScale); |
- } else { |
- // Mix back LR into front center. |
- Mix(BACK_LEFT, CENTER, kEqualPowerScale); |
- Mix(BACK_RIGHT, CENTER, kEqualPowerScale); |
- } |
- } |
- |
- // Mix side LR into: back LR || back center || front LR || front center. |
- if (IsUnaccounted(SIDE_LEFT)) { |
- if (HasOutputChannel(BACK_LEFT)) { |
- // If the input has back LR, mix side LR into back LR, but instead if the |
- // input doesn't have back LR (but output does) copy side LR to back LR. |
- float scale = HasInputChannel(BACK_LEFT) ? kEqualPowerScale : 1; |
- Mix(SIDE_LEFT, BACK_LEFT, scale); |
- Mix(SIDE_RIGHT, BACK_RIGHT, scale); |
- } else if (HasOutputChannel(BACK_CENTER)) { |
- // Mix side LR into back center. |
- Mix(SIDE_LEFT, BACK_CENTER, kEqualPowerScale); |
- Mix(SIDE_RIGHT, BACK_CENTER, kEqualPowerScale); |
- } else if (output_layout_ > CHANNEL_LAYOUT_MONO) { |
- // Mix side LR into front LR. |
- Mix(SIDE_LEFT, LEFT, kEqualPowerScale); |
- Mix(SIDE_RIGHT, RIGHT, kEqualPowerScale); |
- } else { |
- // Mix side LR into front center. |
- Mix(SIDE_LEFT, CENTER, kEqualPowerScale); |
- Mix(SIDE_RIGHT, CENTER, kEqualPowerScale); |
- } |
- } |
- |
- // Mix back center into: back LR || side LR || front LR || front center. |
- if (IsUnaccounted(BACK_CENTER)) { |
- if (HasOutputChannel(BACK_LEFT)) { |
- // Mix back center into back LR. |
- MixWithoutAccounting(BACK_CENTER, BACK_LEFT, kEqualPowerScale); |
- Mix(BACK_CENTER, BACK_RIGHT, kEqualPowerScale); |
- } else if (HasOutputChannel(SIDE_LEFT)) { |
- // Mix back center into side LR. |
- MixWithoutAccounting(BACK_CENTER, SIDE_LEFT, kEqualPowerScale); |
- Mix(BACK_CENTER, SIDE_RIGHT, kEqualPowerScale); |
- } else if (output_layout_ > CHANNEL_LAYOUT_MONO) { |
- // Mix back center into front LR. |
- // TODO(dalecurtis): Not sure about these values? |
- MixWithoutAccounting(BACK_CENTER, LEFT, kEqualPowerScale); |
- Mix(BACK_CENTER, RIGHT, kEqualPowerScale); |
- } else { |
- // Mix back center into front center. |
- // TODO(dalecurtis): Not sure about these values? |
- Mix(BACK_CENTER, CENTER, kEqualPowerScale); |
- } |
- } |
- |
- // Mix LR of center into: front LR || front center. |
- if (IsUnaccounted(LEFT_OF_CENTER)) { |
- if (HasOutputChannel(LEFT)) { |
- // Mix LR of center into front LR. |
- Mix(LEFT_OF_CENTER, LEFT, kEqualPowerScale); |
- Mix(RIGHT_OF_CENTER, RIGHT, kEqualPowerScale); |
- } else { |
- // Mix LR of center into front center. |
- Mix(LEFT_OF_CENTER, CENTER, kEqualPowerScale); |
- Mix(RIGHT_OF_CENTER, CENTER, kEqualPowerScale); |
- } |
- } |
- |
- // Mix LFE into: front center || front LR. |
- if (IsUnaccounted(LFE)) { |
- if (!HasOutputChannel(CENTER)) { |
- // Mix LFE into front LR. |
- MixWithoutAccounting(LFE, LEFT, kEqualPowerScale); |
- Mix(LFE, RIGHT, kEqualPowerScale); |
- } else { |
- // Mix LFE into front center. |
- Mix(LFE, CENTER, kEqualPowerScale); |
- } |
- } |
- |
- // All channels should now be accounted for. |
- DCHECK(unaccounted_inputs_.empty()); |
- |
- // See if the output |matrix_| is simply a remapping matrix. If each input |
- // channel maps to a single output channel we can simply remap. Doing this |
- // programmatically is less fragile than logic checks on channel mappings. |
- for (int output_ch = 0; output_ch < output_channels_; ++output_ch) { |
- int input_mappings = 0; |
- for (int input_ch = 0; input_ch < input_channels_; ++input_ch) { |
- // We can only remap if each row contains a single scale of 1. I.e., each |
- // output channel is mapped from a single unscaled input channel. |
- if ((*matrix_)[output_ch][input_ch] != 1 || ++input_mappings > 1) |
- return false; |
- } |
- } |
- |
- // If we've gotten here, |matrix_| is simply a remapping. |
- return true; |
-} |
- |
ChannelMixer::~ChannelMixer() {} |
void ChannelMixer::Transform(const AudioBus* input, AudioBus* output) { |
@@ -365,40 +76,4 @@ void ChannelMixer::Transform(const AudioBus* input, AudioBus* output) { |
} |
} |
-void MatrixBuilder::AccountFor(Channels ch) { |
- unaccounted_inputs_.erase(std::find( |
- unaccounted_inputs_.begin(), unaccounted_inputs_.end(), ch)); |
-} |
- |
-bool MatrixBuilder::IsUnaccounted(Channels ch) const { |
- return std::find(unaccounted_inputs_.begin(), unaccounted_inputs_.end(), |
- ch) != unaccounted_inputs_.end(); |
-} |
- |
-bool MatrixBuilder::HasInputChannel(Channels ch) const { |
- return ChannelOrder(input_layout_, ch) >= 0; |
-} |
- |
-bool MatrixBuilder::HasOutputChannel(Channels ch) const { |
- return ChannelOrder(output_layout_, ch) >= 0; |
-} |
- |
-void MatrixBuilder::Mix(Channels input_ch, Channels output_ch, float scale) { |
- MixWithoutAccounting(input_ch, output_ch, scale); |
- AccountFor(input_ch); |
-} |
- |
-void MatrixBuilder::MixWithoutAccounting(Channels input_ch, Channels output_ch, |
- float scale) { |
- int input_ch_index = ChannelOrder(input_layout_, input_ch); |
- int output_ch_index = ChannelOrder(output_layout_, output_ch); |
- |
- DCHECK(IsUnaccounted(input_ch)); |
- DCHECK_GE(input_ch_index, 0); |
- DCHECK_GE(output_ch_index, 0); |
- |
- DCHECK_EQ((*matrix_)[output_ch_index][input_ch_index], 0); |
- (*matrix_)[output_ch_index][input_ch_index] = scale; |
-} |
- |
} // namespace media |