auditory.h

Go to the documentation of this file.

/* SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright(c) 2022 Intel Corporation. All rights reserved.
 *
 * Author: Seppo Ingalsuo <seppo.ingalsuo@linux.intel.com>
 */
 
/* Psychoacoustics related functions */
 
#ifndef __SOF_MATH_AUDITORY_H__
#define __SOF_MATH_AUDITORY_H__
 
#include <sof/math/fft.h>
#include <sof/math/log.h>
#include <stdint.h>
 
#define AUDITORY_MAX_MEL_BANDS  256
#define AUDITORY_EPS_Q31    1 /* Smallest nonzero Q1.31 value */
#define AUDITORY_LOG2_2P25_Q16  Q_CONVERT_FLOAT(25.0, 16) /* log2(2^25) */
 
enum psy_mel_log_scale {
    MEL_LOG = 0,
    MEL_LOG10,
    MEL_DB,
};
 
/* Struct to define Mel filterback calculation. The filterbank data is compressed into
 * a single vector from normal (half_fft_bins, mel_bins) size by storing only non-zero
 * weights values.
 *
 * Triangles data Number triangles is mel_bins
 * then for each triangle:
 *  index to next triangle 0, start fft_bin 1, length of this triangle 2,
 *  triangle weight values 3..N
 */
struct psy_mel_filterbank {
    int32_t log_mult; 
    int32_t scale_log2; 
    int32_t samplerate; 
    int16_t start_freq; 
    int16_t end_freq; 
    int16_t *scratch_data1; 
    int16_t *scratch_data2; 
    int16_t *data; 
    int scratch_length1; 
    int scratch_length2; 
    int fft_bins; 
    int half_fft_bins; 
    int mel_bins; 
    int data_length; 
    enum psy_mel_log_scale mel_log_scale; 
    bool slaney_normalize; 
};

int16_t psy_hz_to_mel(int16_t hz);

int16_t psy_mel_to_hz(int16_t mel);

struct processing_module;
int mod_psy_get_mel_filterbank(struct processing_module *mod, struct psy_mel_filterbank *mel_fb);
int mod_psy_free_mel_filterbank(struct processing_module *mod, struct psy_mel_filterbank *mel_fb);

void psy_apply_mel_filterbank_16(struct psy_mel_filterbank *mel_fb, struct icomplex16 *fft_out,
                 int32_t *power_spectra, int16_t *mel_log, int bitshift);

void psy_apply_mel_filterbank_32(struct psy_mel_filterbank *mel_fb, struct icomplex32 *fft_out,
                 int32_t *power_spectra, int32_t *mel_log, int bitshift);
 
#endif /* __SOF_MATH_AUDITORY_H__ */