58 lines
1.9 KiB
C
58 lines
1.9 KiB
C
/******************************************************************************
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*
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* Copyright 2022 Google LLC
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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******************************************************************************/
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/**
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* LC3 - Compute LD-MDCT (Low Delay Modified Discret Cosinus Transform)
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*
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* Reference : Low Complexity Communication Codec (LC3)
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* Bluetooth Specification v1.0
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*/
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#ifndef __LC3_MDCT_H
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#define __LC3_MDCT_H
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#include "common.h"
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/**
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* Forward MDCT transformation
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* dt, sr Duration and samplerate (size of the transform)
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* sr_dst Samplerate destination, scale transforam accordingly
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* x, d Temporal samples and delayed buffer
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* y, d Output `ns` coefficients and `nd` delayed samples
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*
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* `x` and `y` can be the same buffer
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*/
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void lc3_mdct_forward(enum lc3_dt dt, enum lc3_srate sr,
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enum lc3_srate sr_dst, const float *x, float *d, float *y);
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/**
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* Inverse MDCT transformation
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* dt, sr Duration and samplerate (size of the transform)
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* sr_src Samplerate source, scale transforam accordingly
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* x, d Frequency coefficients and delayed buffer
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* y, d Output `ns` samples and `nd` delayed ones
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*
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* `x` and `y` can be the same buffer
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*/
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void lc3_mdct_inverse(enum lc3_dt dt, enum lc3_srate sr,
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enum lc3_srate sr_src, const float *x, float *d, float *y);
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#endif /* __LC3_MDCT_H */
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