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