163 lines
3.4 KiB
C
163 lines
3.4 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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#ifndef __LC3_PRIVATE_H
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#define __LC3_PRIVATE_H
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#include <stdint.h>
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#include <stdbool.h>
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/**
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* Return number of samples, delayed samples and
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* encoded spectrum coefficients within a frame
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* - For encoding, keep 1.25 ms of temporal winodw
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* - For decoding, keep 18 ms of history, aligned on frames, and a frame
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*/
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#define __LC3_NS(dt_us, sr_hz) \
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( (dt_us * sr_hz) / 1000 / 1000 )
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#define __LC3_ND(dt_us, sr_hz) \
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( (dt_us) == 7500 ? 23 * __LC3_NS(dt_us, sr_hz) / 30 \
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: 5 * __LC3_NS(dt_us, sr_hz) / 8 )
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#define __LC3_NT(sr_hz) \
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( (5 * sr_hz) / 4000 )
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#define __LC3_NH(dt_us, sr_hz) \
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( ((3 - ((dt_us) >= 10000)) + 1) * __LC3_NS(dt_us, sr_hz) )
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/**
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* Frame duration 7.5ms or 10ms
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*/
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enum lc3_dt {
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LC3_DT_7M5,
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LC3_DT_10M,
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LC3_NUM_DT
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};
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/**
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* Sampling frequency
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*/
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enum lc3_srate {
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LC3_SRATE_8K,
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LC3_SRATE_16K,
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LC3_SRATE_24K,
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LC3_SRATE_32K,
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LC3_SRATE_48K,
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LC3_NUM_SRATE,
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};
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/**
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* Encoder state and memory
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*/
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typedef struct lc3_attdet_analysis {
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int32_t en1, an1;
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int p_att;
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} lc3_attdet_analysis_t;
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struct lc3_ltpf_hp50_state {
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int64_t s1, s2;
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};
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typedef struct lc3_ltpf_analysis {
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bool active;
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int pitch;
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float nc[2];
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struct lc3_ltpf_hp50_state hp50;
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int16_t x_12k8[384];
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int16_t x_6k4[178];
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int tc;
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} lc3_ltpf_analysis_t;
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typedef struct lc3_spec_analysis {
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float nbits_off;
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int nbits_spare;
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} lc3_spec_analysis_t;
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struct lc3_encoder {
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enum lc3_dt dt;
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enum lc3_srate sr, sr_pcm;
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lc3_attdet_analysis_t attdet;
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lc3_ltpf_analysis_t ltpf;
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lc3_spec_analysis_t spec;
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int16_t *xt;
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float *xs, *xd, s[0];
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};
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#define LC3_ENCODER_BUFFER_COUNT(dt_us, sr_hz) \
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( ( __LC3_NS(dt_us, sr_hz) + __LC3_NT(sr_hz) ) / 2 + \
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__LC3_NS(dt_us, sr_hz) + __LC3_ND(dt_us, sr_hz) )
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#define LC3_ENCODER_MEM_T(dt_us, sr_hz) \
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struct { \
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struct lc3_encoder __e; \
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float __s[LC3_ENCODER_BUFFER_COUNT(dt_us, sr_hz)]; \
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}
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/**
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* Decoder state and memory
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*/
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typedef struct lc3_ltpf_synthesis {
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bool active;
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int pitch;
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float c[2*12], x[12];
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} lc3_ltpf_synthesis_t;
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typedef struct lc3_plc_state {
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uint16_t seed;
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int count;
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float alpha;
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} lc3_plc_state_t;
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struct lc3_decoder {
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enum lc3_dt dt;
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enum lc3_srate sr, sr_pcm;
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lc3_ltpf_synthesis_t ltpf;
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lc3_plc_state_t plc;
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float *xh, *xs, *xd, *xg, s[0];
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};
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#define LC3_DECODER_BUFFER_COUNT(dt_us, sr_hz) \
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( __LC3_NH(dt_us, sr_hz) + __LC3_ND(dt_us, sr_hz) + \
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__LC3_NS(dt_us, sr_hz) )
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#define LC3_DECODER_MEM_T(dt_us, sr_hz) \
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struct { \
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struct lc3_decoder __d; \
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float __s[LC3_DECODER_BUFFER_COUNT(dt_us, sr_hz)]; \
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}
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#endif /* __LC3_PRIVATE_H */
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