2250b05778
Two new classes are added to WebRTC from Chrome: ChannelMixer and ChannelMixingMatrix but they are not yet utilized in the audio path for WebRTC. The idea is to utilize these new classes when adding support for multi- channel encoding/decoding in WebRTC/Chrome. Adds support for a new enumerator call webrtc::ChannelLayout and some helper methods which maps between channel layout and number of channels. These parts are also copied from Chrome. Minor (cosmetic) changes are also done on the AudioFrame to prepare for upcoming work. Bug: webrtc:10783 Change-Id: I6cd7a13a3bc1c8bbfa19bc974c7a011d22d19197 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/141674 Commit-Queue: Henrik Andreassson <henrika@webrtc.org> Reviewed-by: Henrik Lundin <henrik.lundin@webrtc.org> Cr-Commit-Position: refs/heads/master@{#28482}
75 lines
2.8 KiB
C++
75 lines
2.8 KiB
C++
/*
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* Copyright (c) 2019 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef AUDIO_UTILITY_CHANNEL_MIXING_MATRIX_H_
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#define AUDIO_UTILITY_CHANNEL_MIXING_MATRIX_H_
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#include <vector>
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#include "api/audio/channel_layout.h"
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namespace webrtc {
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class ChannelMixingMatrix {
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public:
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ChannelMixingMatrix(ChannelLayout input_layout,
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int input_channels,
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ChannelLayout output_layout,
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int output_channels);
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~ChannelMixingMatrix();
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// Create the transformation matrix of input channels to output channels.
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// Updates the empty matrix with the transformation, and returns true
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// if the transformation is just a remapping of channels (no mixing).
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// The size of |matrix| is |output_channels| x |input_channels|, i.e., the
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// number of rows equals the number of output channels and the number of
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// columns corresponds to the number of input channels.
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// This file is derived from Chromium's media/base/channel_mixing_matrix.h.
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bool CreateTransformationMatrix(std::vector<std::vector<float>>* matrix);
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private:
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// Result transformation of input channels to output channels
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std::vector<std::vector<float>>* matrix_;
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// Input and output channel layout provided during construction.
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ChannelLayout input_layout_;
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int input_channels_;
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ChannelLayout output_layout_;
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int output_channels_;
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// Helper variable for tracking which inputs are currently unaccounted,
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// should be empty after construction completes.
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std::vector<Channels> unaccounted_inputs_;
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// Helper methods for managing unaccounted input channels.
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void AccountFor(Channels ch);
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bool IsUnaccounted(Channels ch) const;
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// Helper methods for checking if |ch| exists in either |input_layout_| or
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// |output_layout_| respectively.
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bool HasInputChannel(Channels ch) const;
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bool HasOutputChannel(Channels ch) const;
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// Helper methods for updating |matrix_| with the proper value for
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// mixing |input_ch| into |output_ch|. MixWithoutAccounting() does not
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// remove the channel from |unaccounted_inputs_|.
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void Mix(Channels input_ch, Channels output_ch, float scale);
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void MixWithoutAccounting(Channels input_ch, Channels output_ch, float scale);
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// Delete the copy constructor and assignment operator.
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ChannelMixingMatrix(const ChannelMixingMatrix& other) = delete;
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ChannelMixingMatrix& operator=(const ChannelMixingMatrix& other) = delete;
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};
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} // namespace webrtc
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#endif // AUDIO_UTILITY_CHANNEL_MIXING_MATRIX_H_
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