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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>
/**
* Return number of samples, delayed samples and
* encoded spectrum coefficients within a frame
* - For encoding, keep 1.25 ms of temporal winodw
* - For decoding, keep 18 ms of history, aligned on frames, and a frame
*/
#define __LC3_NS(dt_us, sr_hz) \
( (dt_us * sr_hz) / 1000 / 1000 )
#define __LC3_ND(dt_us, sr_hz) \
( (dt_us) == 7500 ? 23 * __LC3_NS(dt_us, sr_hz) / 30 \
: 5 * __LC3_NS(dt_us, sr_hz) / 8 )
#define __LC3_NT(sr_hz) \
( (5 * sr_hz) / 4000 )
#define __LC3_NH(dt_us, sr_hz) \
( ((3 - ((dt_us) >= 10000)) + 1) * __LC3_NS(dt_us, sr_hz) )
/**
* Frame duration 7.5ms or 10ms
*/
enum lc3_dt {
LC3_DT_7M5,
LC3_DT_10M,
LC3_NUM_DT
};
/**
* Sampling frequency
*/
enum lc3_srate {
LC3_SRATE_8K,
LC3_SRATE_16K,
LC3_SRATE_24K,
LC3_SRATE_32K,
LC3_SRATE_48K,
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;
int16_t *xt;
float *xs, *xd, s[0];
};
#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 __s[LC3_ENCODER_BUFFER_COUNT(dt_us, sr_hz)]; \
}
/**
* 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;
float *xh, *xs, *xd, *xg, s[0];
};
#define LC3_DECODER_BUFFER_COUNT(dt_us, sr_hz) \
( __LC3_NH(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 __s[LC3_DECODER_BUFFER_COUNT(dt_us, sr_hz)]; \
}
#endif /* __LC3_PRIVATE_H */
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