| 1 | /* |
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| 2 | Copyright 2018 Google Inc. All Rights Reserved. |
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| 3 | |
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| 4 | Licensed under the Apache License, Version 2.0 (the "License"); |
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| 5 | you may not use this file except in compliance with the License. |
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| 6 | You may obtain a copy of the License at |
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| 7 | |
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| 8 | http://www.apache.org/licenses/LICENSE-2.0 |
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| 9 | |
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| 10 | Unless required by applicable law or agreed to in writing, software |
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| 11 | distributed under the License is distributed on an "AS-IS" BASIS, |
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| 12 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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| 13 | See the License for the specific language governing permissions and |
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| 14 | limitations under the License. |
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| 15 | */ |
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| 16 | |
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| 17 | #ifndef RESONANCE_AUDIO_AMBISONICS_FOA_ROTATOR_H_ |
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| 18 | #define RESONANCE_AUDIO_AMBISONICS_FOA_ROTATOR_H_ |
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| 19 | |
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| 20 | #include "base/audio_buffer.h" |
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| 21 | #include "base/spherical_angle.h" |
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| 22 | |
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| 23 | namespace vraudio { |
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| 24 | |
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| 25 | // Rotator for first order ambisonic soundfields. It supports ACN channel |
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| 26 | // ordering and SN3D normalization (AmbiX). |
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| 27 | class FoaRotator { |
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| 28 | public: |
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| 29 | // @param target_rotation Target rotation to be applied to the input buffer. |
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| 30 | // @param input First order soundfield input buffer to be rotated. |
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| 31 | // @param output Pointer to output buffer. |
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| 32 | // @return True if rotation has been applied. |
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| 33 | bool Process(const WorldRotation& target_rotation, const AudioBuffer& input, |
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| 34 | AudioBuffer* output); |
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| 35 | |
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| 36 | private: |
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| 37 | // Method which rotates a specified chunk of data in the AudioBuffer. |
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| 38 | // |
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| 39 | // @param target_rotation Target rotation to be applied to the soundfield. |
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| 40 | // @param start_location Sample index in the soundfield where the rotation |
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| 41 | // should begin. |
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| 42 | // @param duration Number of samples in soundfield to be rotated. |
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| 43 | // @param input First order soundfield input buffer to be rotated. |
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| 44 | // @param output Pointer to output buffer. |
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| 45 | void Rotate(const WorldRotation& target_rotation, size_t start_location, |
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| 46 | size_t duration, const AudioBuffer& input, AudioBuffer* output); |
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| 47 | |
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| 48 | // Current rotation which is used in the interpolation process in order to |
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| 49 | // perform a smooth rotation. Initialized with an identity matrix. |
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| 50 | WorldRotation current_rotation_; |
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| 51 | |
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| 52 | // Preallocation of temporary variables used during rotation. |
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| 53 | AudioPosition temp_audio_position_; |
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| 54 | WorldPosition temp_world_position_; |
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| 55 | AudioPosition temp_rotated_audio_position_; |
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| 56 | WorldPosition temp_rotated_world_position_; |
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| 57 | }; |
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| 58 | |
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| 59 | } // namespace vraudio |
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| 60 | |
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| 61 | #endif // RESONANCE_AUDIO_AMBISONICS_FOA_ROTATOR_H_ |
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| 62 | |
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