| /****************************************************************************** |
| * |
| * 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 - Temporal Noise Shaping |
| * |
| * Reference : Low Complexity Communication Codec (LC3) |
| * Bluetooth Specification v1.0 |
| */ |
| |
| #ifndef __LC3_TNS_H |
| #define __LC3_TNS_H |
| |
| #include "common.h" |
| #include "bits.h" |
| |
| |
| /** |
| * Bitstream data |
| */ |
| |
| typedef struct lc3_tns_data { |
| int nfilters; |
| bool lpc_weighting; |
| int rc_order[2]; |
| int rc[2][8]; |
| } lc3_tns_data_t; |
| |
| |
| /* ---------------------------------------------------------------------------- |
| * Encoding |
| * -------------------------------------------------------------------------- */ |
| |
| /** |
| * TNS analysis |
| * dt, bw Duration and bandwidth of the frame |
| * nn_flag True when high energy detected near Nyquist frequency |
| * nbytes Size in bytes of the frame |
| * data Return bitstream data |
| * x Spectral coefficients, filtered as output |
| */ |
| void lc3_tns_analyze(enum lc3_dt dt, enum lc3_bandwidth bw, |
| bool nn_flag, int nbytes, lc3_tns_data_t *data, float *x); |
| |
| /** |
| * Return number of bits coding the data |
| * data Bitstream data |
| * return Bit consumption |
| */ |
| int lc3_tns_get_nbits(const lc3_tns_data_t *data); |
| |
| /** |
| * Put bitstream data |
| * bits Bitstream context |
| * data Bitstream data |
| */ |
| void lc3_tns_put_data(lc3_bits_t *bits, const lc3_tns_data_t *data); |
| |
| |
| /* ---------------------------------------------------------------------------- |
| * Decoding |
| * -------------------------------------------------------------------------- */ |
| |
| /** |
| * Get bitstream data |
| * bits Bitstream context |
| * dt, bw Duration and bandwidth of the frame |
| * nbytes Size in bytes of the frame |
| * data Bitstream data |
| */ |
| void lc3_tns_get_data(lc3_bits_t *bits, |
| enum lc3_dt dt, enum lc3_bandwidth bw, int nbytes, lc3_tns_data_t *data); |
| |
| /** |
| * TNS synthesis |
| * dt, bw Duration and bandwidth of the frame |
| * data Bitstream data |
| * x Spectral coefficients, filtered as output |
| */ |
| void lc3_tns_synthesize(enum lc3_dt dt, enum lc3_bandwidth bw, |
| const lc3_tns_data_t *data, float *x); |
| |
| |
| #endif /* __LC3_TNS_H */ |