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/******************************************************************************
*
* 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.
*
******************************************************************************/
#ifndef __LC3_PRIVATE_H
#define __LC3_PRIVATE_H
#include <stdint.h>
#include <stdbool.h>
/**
* Characteristics
*
* - The number of samples within a frame
*
* - The number of MDCT delayed samples, sum of half a frame and
* an ovelap of future by 1.25 ms (2.5ms, 5ms and 10ms frame durations)
* or 2 ms (7.5ms frame duration).
*
* - For decoding, keep 18 ms of history, aligned on a frame
*
* - For encoding, keep 1.25 ms of temporal previous samples
*/
#define LC3_NS(dt_us, sr_hz) \
( (dt_us) * (sr_hz) / 1000 / 1000 )
#define LC3_ND(dt_us, sr_hz) \
( LC3_NS(dt_us, sr_hz) / 2 + \
LC3_NS((dt_us) == 7500 ? 2000 : 1250, sr_hz) )
#define LC3_NH(dt_us, sr_hz) \
( (sr_hz) > 48000 ? 0 : ( LC3_NS(18000, sr_hz) + \
LC3_NS(dt_us, sr_hz) - (LC3_NS(18000, sr_hz) % LC3_NS(dt_us, sr_hz)) ) )
#define LC3_NT(sr_hz) \
( LC3_NS(1250, sr_hz) )
/**
* Frame duration
*/
enum lc3_dt {
LC3_DT_2M5 = 0,
LC3_DT_5M = 1,
LC3_DT_7M5 = 2,
LC3_DT_10M = 3,
LC3_NUM_DT
};
/**
* Sampling frequency and high-resolution mode
*/
enum lc3_srate {
LC3_SRATE_8K,
LC3_SRATE_16K,
LC3_SRATE_24K,
LC3_SRATE_32K,
LC3_SRATE_48K,
LC3_SRATE_48K_HR,
LC3_SRATE_96K_HR,
LC3_NUM_SRATE
};
/**
* Encoder state and memory
*/
typedef struct lc3_attdet_analysis {
int32_t en1, an1;
int p_att;
} lc3_attdet_analysis_t;
struct lc3_ltpf_hp50_state {
int64_t s1, s2;
};
typedef struct lc3_ltpf_analysis {
bool active;
int pitch;
float nc[2];
struct lc3_ltpf_hp50_state hp50;
int16_t x_12k8[384];
int16_t x_6k4[178];
int tc;
} lc3_ltpf_analysis_t;
typedef struct lc3_spec_analysis {
float nbits_off;
int nbits_spare;
} lc3_spec_analysis_t;
struct lc3_encoder {
enum lc3_dt dt;
enum lc3_srate sr, sr_pcm;
lc3_attdet_analysis_t attdet;
lc3_ltpf_analysis_t ltpf;
lc3_spec_analysis_t spec;
int xt_off, xs_off, xd_off;
float x[1];
};
#define LC3_ENCODER_BUFFER_COUNT(dt_us, sr_hz) \
( ( LC3_NS(dt_us, sr_hz) + LC3_NT(sr_hz) ) / 2 + \
LC3_NS(dt_us, sr_hz) + LC3_ND(dt_us, sr_hz) )
#define LC3_ENCODER_MEM_T(dt_us, sr_hz) \
struct { \
struct lc3_encoder __e; \
float __x[LC3_ENCODER_BUFFER_COUNT(dt_us, sr_hz)-1]; \
}
/**
* Decoder state and memory
*/
typedef struct lc3_ltpf_synthesis {
bool active;
int pitch;
float c[2*12], x[12];
} lc3_ltpf_synthesis_t;
typedef struct lc3_plc_state {
uint16_t seed;
int count;
float alpha;
} lc3_plc_state_t;
struct lc3_decoder {
enum lc3_dt dt;
enum lc3_srate sr, sr_pcm;
lc3_ltpf_synthesis_t ltpf;
lc3_plc_state_t plc;
int xh_off, xs_off, xd_off, xg_off;
float x[1];
};
#define LC3_DECODER_BUFFER_COUNT(dt_us, sr_hz) \
( LC3_NH(dt_us, sr_hz) + LC3_NS(dt_us, sr_hz) + \
LC3_ND(dt_us, sr_hz) + LC3_NS(dt_us, sr_hz) )
#define LC3_DECODER_MEM_T(dt_us, sr_hz) \
struct { \
struct lc3_decoder __d; \
float __x[LC3_DECODER_BUFFER_COUNT(dt_us, sr_hz)-1]; \
}
/**
* Change the visibility of interface functions
*/
#ifdef _WIN32
#define LC3_EXPORT __declspec(dllexport)
#else
#define LC3_EXPORT __attribute__((visibility ("default")))
#endif
#endif /* __LC3_PRIVATE_H */
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