Audio.cpp

#include <math.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <webrtc_vad.h>

#include "Audio.h"

using namespace std;

class AudioWindow {
  private:
    int *window;
    int in_idx;
    int out_idx;
    int sum;
    int window_size = 0;

  public:
    AudioWindow(int window_size) : window_size(window_size)
    {
        window = (int *)calloc(sizeof(int), window_size + 1);
        in_idx = 0;
        out_idx = 1;
        sum = 0;
    };
    ~AudioWindow()
    {
        free(window);
    };
    int put(int val)
    {
        sum = sum + val - window[out_idx];
        window[in_idx] = val;
        in_idx = in_idx == window_size ? 0 : in_idx + 1;
        out_idx = out_idx == window_size ? 0 : out_idx + 1;
        return sum;
    };
};

AudioFrame::AudioFrame(){};
AudioFrame::AudioFrame(int len) : len(len)
{
    start = 0;
};
AudioFrame::~AudioFrame(){};
int AudioFrame::set_start(int val)
{
    start = val < 0 ? 0 : val;
    return start;
};

int AudioFrame::set_end(int val, int max_len)
{

    float num_samples = val - start;
    float frame_length = 400;
    float frame_shift = 160;
    float num_new_samples =
        ceil((num_samples - 400) / frame_shift) * frame_shift + frame_length;

    end = start + num_new_samples;
    len = (int)num_new_samples;
    if (end > max_len)
        printf("frame end > max_len!!!!!!!\n");
    return end;
};

int AudioFrame::get_start()
{
    return start;
};

int AudioFrame::get_len()
{
    return len;
};

int AudioFrame::disp()
{
    printf("not imp!!!!\n");

    return 0;
};

Audio::Audio(int data_type) : data_type(data_type)
{
    speech_buff = NULL;
    speech_data = NULL;
    align_size = 1360;
}

Audio::Audio(int data_type, int size) : data_type(data_type)
{
    speech_buff = NULL;
    speech_data = NULL;
    align_size = (float)size;
}

Audio::~Audio()
{
    if (speech_buff != NULL) {
        free(speech_buff);
        free(speech_data);
    }
}

void Audio::disp()
{
    printf("Audio time is %f s. len is %d\n", (float)speech_len / 16000,
           speech_len);
}

bool Audio::loadwav(const char *filename)
{

    if (speech_buff != NULL) {
        free(speech_buff);
        free(speech_data);
    }

    offset = 0;

    FILE *fp;
    fp = fopen(filename, "rb");
    if (fp == nullptr)
        return false;
    fseek(fp, 0, SEEK_END);
    uint32_t nFileLen = ftell(fp);
    fseek(fp, 44, SEEK_SET);

    speech_len = (nFileLen - 44) / 2;
    speech_align_len = (int)(ceil((float)speech_len / align_size) * align_size);
    speech_buff = (int16_t *)malloc(sizeof(int16_t) * speech_align_len);
    memset(speech_buff, 0, sizeof(int16_t) * speech_align_len);
    int ret = fread(speech_buff, sizeof(int16_t), speech_len, fp);
    fclose(fp);

    speech_data = (float *)malloc(sizeof(float) * speech_align_len);
    memset(speech_data, 0, sizeof(float) * speech_align_len);
    int i;
    float scale = 1;

    if (data_type == 1) {
        scale = 32768;
    }

    for (i = 0; i < speech_len; i++) {
        speech_data[i] = (float)speech_buff[i] / scale;
    }

    AudioFrame *frame = new AudioFrame(speech_len);
    frame_queue.push(frame);
    return true;
}

int Audio::fetch_chunck(float *&dout, int len)
{
    if (offset >= speech_align_len) {
        dout = NULL;
        return S_ERR;
    } else if (offset == speech_align_len - len) {
        dout = speech_data + offset;
        offset = speech_align_len;
        // 临时解决
        AudioFrame *frame = frame_queue.front();
        frame_queue.pop();
        delete frame;

        return S_END;
    } else {
        dout = speech_data + offset;
        offset += len;
        return S_MIDDLE;
    }
}

int Audio::fetch(float *&dout, int &len, int &flag)
{
    if (frame_queue.size() > 0) {
        AudioFrame *frame = frame_queue.front();
        frame_queue.pop();

        dout = speech_data + frame->get_start();
        len = frame->get_len();
        delete frame;
        flag = S_END;
        return 1;
    } else {
        return 0;
    }
}

void Audio::padding()
{

    float num_samples = speech_len;
    float frame_length = 400;
    float frame_shift = 160;
    float num_frames = floor((num_samples + (frame_shift / 2)) / frame_shift);
    float num_new_samples = (num_frames - 1) * frame_shift + frame_length;
    float num_padding = num_new_samples - num_samples;
    float num_left_padding = (frame_length - frame_shift) / 2;
    float num_right_padding = num_padding - num_left_padding;

    float *new_data = (float *)malloc(num_new_samples * sizeof(float));
    int i;
    int tmp_off = 0;
    for (i = 0; i < num_left_padding; i++) {
        int ii = num_left_padding - i - 1;
        new_data[i] = speech_data[ii];
    }
    tmp_off = num_left_padding;
    memcpy(new_data + tmp_off, speech_data, speech_len * sizeof(float));
    tmp_off += speech_len;

    for (i = 0; i < num_right_padding; i++) {
        int ii = speech_len - i - 1;
        new_data[tmp_off + i] = speech_data[ii];
    }
    free(speech_data);
    speech_data = new_data;
    speech_len = num_new_samples;

    AudioFrame *frame = new AudioFrame(num_new_samples);
    frame_queue.push(frame);
    frame = frame_queue.front();
    frame_queue.pop();
    delete frame;
}

#define UNTRIGGERED 0
#define TRIGGERED   1

#define SPEECH_LEN_5S  (16000 * 5)
#define SPEECH_LEN_10S (16000 * 10)
#define SPEECH_LEN_20S (16000 * 20)
#define SPEECH_LEN_30S (16000 * 30)

void Audio::split()
{
    VadInst *handle = WebRtcVad_Create();
    WebRtcVad_Init(handle);
    WebRtcVad_set_mode(handle, 2);
    int window_size = 10;
    AudioWindow audiowindow(window_size);
    int status = UNTRIGGERED;
    int offset = 0;
    int fs = 16000;
    int step = 480;

    AudioFrame *frame;

    frame = frame_queue.front();
    frame_queue.pop();
    delete frame;
    frame = NULL;

    while (offset < speech_len - step) {
        int n = WebRtcVad_Process(handle, fs, speech_buff + offset, step);
        if (status == UNTRIGGERED && audiowindow.put(n) >= window_size - 1) {
            frame = new AudioFrame();
            int start = offset - step * (window_size - 1);
            frame->set_start(start);
            status = TRIGGERED;
        } else if (status == TRIGGERED) {
            int win_weight = audiowindow.put(n);
            int voice_len = (offset - frame->get_start());
            int gap = 0;
            if (voice_len < SPEECH_LEN_5S) {
                offset += step;
                continue;
            } else if (voice_len < SPEECH_LEN_10S) {
                gap = 1;
            } else if (voice_len < SPEECH_LEN_20S) {
                gap = window_size / 5;
            } else {
                gap = window_size / 2;
            }

            if (win_weight < gap) {
                status = UNTRIGGERED;
                offset = frame->set_end(offset, speech_align_len);
                frame_queue.push(frame);
                frame = NULL;
            }
        }
        offset += step;
    }

    if (frame != NULL) {
        frame->set_end(speech_len, speech_align_len);
        frame_queue.push(frame);
        frame = NULL;
    }
    WebRtcVad_Free(handle);
}