| 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_UTILS_BUFFER_CROSSFADER_H_ |
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| 18 | #define RESONANCE_AUDIO_UTILS_BUFFER_CROSSFADER_H_ |
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| 19 | |
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| 20 | #include "base/audio_buffer.h" |
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| 21 | |
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| 22 | namespace vraudio { |
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| 23 | |
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| 24 | // Class that takes two input buffers and produces an output buffer by applying |
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| 25 | // linear crossfade between the inputs. |
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| 26 | class BufferCrossfader { |
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| 27 | public: |
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| 28 | explicit BufferCrossfader(size_t num_frames); |
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| 29 | |
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| 30 | // Applies linear crossfade for given input buffers and stores the result in |
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| 31 | // |output| buffer. Note that, in-place processing is *not* supported by this |
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| 32 | // method, the output buffer must be different than the input buffers. |
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| 33 | // |
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| 34 | // @param input_fade_in Input buffer to fade-in to. |
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| 35 | // @param input_fade_out Input buffer to fade-out from. |
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| 36 | // @param output Output buffer to store the crossfaded result. |
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| 37 | void ApplyLinearCrossfade(const AudioBuffer& input_fade_in, |
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| 38 | const AudioBuffer& input_fade_out, |
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| 39 | AudioBuffer* output) const; |
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| 40 | |
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| 41 | private: |
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| 42 | // Stereo audio buffer to store crossfade decay and growth multipliers. |
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| 43 | AudioBuffer crossfade_buffer_; |
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| 44 | }; |
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| 45 | |
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| 46 | } // namespace vraudio |
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| 47 | |
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| 48 | #endif // RESONANCE_AUDIO_UTILS_BUFFER_CROSSFADER_H_ |
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| 49 | |
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