File ns_audio_melspec.h

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#ifndef __NS_AUDIO_MELSPEC_H__
#define __NS_AUDIO_MELSPEC_H__

#ifdef __cplusplus
extern "C" {
#endif

#include "arm_math.h"
#include "ns_audio_features_common.h"

typedef struct {
    uint8_t *arena;
    uint32_t sample_frequency;
    uint32_t num_fbank_bins;
    uint32_t low_freq;
    uint32_t high_freq;
    uint32_t num_frames;
    uint32_t frame_len;
    uint32_t frame_len_pow2;
    float compression_exponent;
    float *melspecBuffer; //[2 * MELSPEC_FRAME_LEN]; // interleaved real + imaginary parts
    ns_fbanks_cfg_t fbc;
} ns_melspec_cfg_t;

// Arena should be enough to accomodate the various buffers
// e.g. MFCC_ARENA_SIZE  32*(MELSPEC_FRAME_LEN_POW2*2 + MELSPEC_NUM_FBANK_BINS*52))
// where '32' is size of float and int32_t

// #ifndef STFT_OVERRIDE_DEFAULTS
//     #define MELSPEC_SAMP_FREQ 16000
//     #define MELSPEC_FRAME_LEN 512
//     #define MELSPEC_FRAME_LEN_POW2 512
//     #define MELSPEC_NUM_FRAMES 100
//     #define MELSPEC_NUM_FBANK_BINS 128
//     #define MELSPEC_MEL_LOW_FREQ 0
//     #define MELSPEC_MEL_HIGH_FREQ 8000
//     #define MELSPEC_COMPRESSION_EXPONENT 0.3
// #endif

extern void ns_melspec_init(ns_melspec_cfg_t *c);

extern void
ns_melspec_audio_to_stft(ns_melspec_cfg_t *c, const int16_t *audio_data, float32_t *stft_out);

extern void ns_melspec_stft_to_audio(ns_melspec_cfg_t *c, float32_t *stft_in, int16_t *audio_out);

extern void ns_melspec_stft_to_compressed_melspec(
    ns_melspec_cfg_t *c, const float32_t *stft_in, float32_t *melspec_out);

extern void
ns_melspec_melspec_to_stft(ns_melspec_cfg_t *c, const float32_t *melspec_in, float32_t *stft_out);

#ifdef __cplusplus
}
#endif
#endif