106 lines
3.6 KiB
C

// Copyright 2015-2019 Espressif Systems (Shanghai) PTE LTD
//
// 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 _ESP_AEC_H_
#define _ESP_AEC_H_
#include <stdint.h>
#ifdef __cplusplus
extern "C" {
#endif
#define USE_AEC_FFT // Not kiss_fft
#define AEC_SAMPLE_RATE 16000 // Only Support 16000Hz
#define AEC_FRAME_LENGTH_MS 32
typedef struct aec_handle_t aec_handle_t;
typedef enum {
AEC_MODE_SR_LOW_COST = 0, // Low Cost AEC fro speech recognition
AEC_MODE_SR_HIGH_PERF = 1, // High Perforamce AEC for speech recognition
AEC_MODE_VOIP_LOW_COST = 3, // Low Cost AEC for voice communication
AEC_MODE_VOIP_HIGH_PERF = 4, // High Perforamce AEC for voice communication
} aec_mode_t;
/**
* @brief Creates an instance to the AEC structure.
* Please get frame size by aec_get_chunksize() function
*
* @param sample_rate The Sampling frequency (Hz) must be 16000.
* @param filter_length Number of filter, recommend to set 4. The larger the filter_length, the more resource consumption.
* @param channel_num The input microphone channel number
* @param mode The mode of AEC, recommend to set AEC_MODE_SR_LOW_COST
* @return
* - NULL: Create failed
* - Others: The instance of AEC
*/
aec_handle_t *aec_create(int sample_rate, int filter_length, int channel_num, aec_mode_t mode);
/**
* @brief Creates an instance to the AEC structure, same with aec_create().
*
* @param filter_length Number of filter, recommend to set 4. The larger the filter_length, the more resource consumption.
* @param channel_num The input microphone channel number
* @param mode The mode of AEC, recommend to set AEC_MODE_SR_LOW_COST
* @return
* - NULL: Create failed
* - Others: The instance of AEC
*/
aec_handle_t *aec_pro_create(int filter_length, int channel_num, aec_mode_t mode);
/**
* @brief Performs echo cancellation a frame, based on the audio sent to the speaker and frame from mic.
*
* @warning The indata, refdata and outdata must be 16-bit signed. please allocate memory by heap_caps_aligned_alloc().
*
* @param inst The instance of AEC. Format for multi-channel data is "ch0 ch0 ch0 ..., ch1 ch1 ch1 ..."
* @param indata An array of 16-bit signed audio samples from mic.
* @param refdata An array of 16-bit signed audio samples sent to the speaker.
* @param outdata Returns near-end signal with echo removed. Format for multi-channel data is "ch0 ch0 ch0..., ch1 ch1 ch1 ..."
* @return None
*
*/
void aec_process(const aec_handle_t *handel, int16_t *indata, int16_t *refdata, int16_t *outdata);
/**
* @brief Get frame size of AEC (the samples of one frame)
* @param handle The instance of AEC.
* @return Frame size
*/
int aec_get_chunksize(const aec_handle_t *handle);
/**
* @brief Get AEC mode string
*
* @param aec_mode The mode of AEC.
*
* @return AEC mode string
*/
char * aec_get_mode_string(aec_mode_t aec_mode);
/**
* @brief Free the AEC instance
*
* @param inst The instance of AEC.
*
* @return None
*
*/
void aec_destroy(aec_handle_t *handel);
#ifdef __cplusplus
}
#endif
#endif //_ESP_AEC_H_