基于RNN的音频降噪算法 (附完整C代码)

前几天无意间看到一个项目rnnoise。

项目地址: https://github.com/xiph/rnnoise

基于RNN的音频降噪算法。

采用的是 GRU/LSTM 模型。

阅读下训练代码，可惜的是作者没有提供数据训练集。

不过基本可以断定他采用的数据集里，肯定有urbansound8k。

urbansound8k 数据集地址:

https://serv.cusp.nyu.edu/projects/urbansounddataset/urbansound8k.html

也可以考虑采用用作者训练的模型来构建数据集的做法，不过即费事，也麻烦。

经过实测，降噪效果很不错，特别是在背景噪声比较严重的情况下。

不过作者仅仅提供 pcm 的代码示例，并且还只支持48K采样率，

( 明显是为了兼容其另一个 项目  opus)

在很多应用场景下，这很不方便。

尽管稍微有点麻烦，但是事在人为，花了点时间，稍作修改。

具体修改如下：

1.支持wav格式

 采用dr_wav(https://github.com/mackron/dr_libs/blob/master/dr_wav.h )

2.支持全部采样率

采样率的处理问题，采用简单粗暴法，

详情请移步博主另一篇小文《简洁明了的插值音频重采样算法例子 (附完整C代码)》

3.增加CMake文件

4.增加测试用 示例音频sample.wav 

取自(https://github.com/orctom/rnnoise-java)

贴上完整示例代码 ：

/* Copyright (c) 2017 Mozilla */
/*
   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions
   are met:

   - Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.

   - Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.

   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#include <stdio.h>
#include "rnnoise.h"
#include <stdlib.h>
#include <stdint.h>

#define DR_WAV_IMPLEMENTATION

#include "dr_wav.h"


void wavWrite_int16(char *filename, int16_t *buffer, int sampleRate, uint32_t totalSampleCount) {
    drwav_data_format format;
    format.container = drwav_container_riff;
    format.format = DR_WAVE_FORMAT_PCM;
    format.channels = 1;
    format.sampleRate = (drwav_uint32) sampleRate;
    format.bitsPerSample = 16;
    drwav *pWav = drwav_open_file_write(filename, &format);
    if (pWav) {
        drwav_uint64 samplesWritten = drwav_write(pWav, totalSampleCount, buffer);
        drwav_uninit(pWav);
        if (samplesWritten != totalSampleCount) {
            fprintf(stderr, "ERROR
");
            exit(1);
        }
    }
}

int16_t *wavRead_int16(char *filename, uint32_t *sampleRate, uint64_t *totalSampleCount) {
    unsigned int channels;
    int16_t *buffer = drwav_open_and_read_file_s16(filename, &channels, sampleRate, totalSampleCount);
    if (buffer == NULL) {
        fprintf(stderr, "ERROR
");
        exit(1);
    }
    if (channels != 1) {
        drwav_free(buffer);
        buffer = NULL;
        *sampleRate = 0;
        *totalSampleCount = 0;
    }
    return buffer;
}

void splitpath(const char *path, char *drv, char *dir, char *name, char *ext) {
    const char *end;
    const char *p;
    const char *s;
    if (path[0] && path[1] == ':') {
        if (drv) {
            *drv++ = *path++;
            *drv++ = *path++;
            *drv = '';
        }
    } else if (drv)
        *drv = '';
    for (end = path; *end && *end != ':';)
        end++;
    for (p = end; p > path && *--p != '\' && *p != '/';)
        if (*p == '.') {
            end = p;
            break;
        }
    if (ext)
        for (s = end; (*ext = *s++);)
            ext++;
    for (p = end; p > path;)
        if (*--p == '\' || *p == '/') {
            p++;
            break;
        }
    if (name) {
        for (s = p; s < end;)
            *name++ = *s++;
        *name = '';
    }
    if (dir) {
        for (s = path; s < p;)
            *dir++ = *s++;
        *dir = '';
    }
}

void resampleData(const int16_t *sourceData, int32_t sampleRate, uint32_t srcSize, int16_t *destinationData,
                  int32_t newSampleRate) {
    if (sampleRate == newSampleRate) {
        memcpy(destinationData, sourceData, srcSize * sizeof(int16_t));
        return;
    }
    uint32_t last_pos = srcSize - 1;
    uint32_t dstSize = (uint32_t) (srcSize * ((float) newSampleRate / sampleRate));
    for (uint32_t idx = 0; idx < dstSize; idx++) {
        float index = ((float) idx * sampleRate) / (newSampleRate);
        uint32_t p1 = (uint32_t) index;
        float coef = index - p1;
        uint32_t p2 = (p1 == last_pos) ? last_pos : p1 + 1;
        destinationData[idx] = (int16_t) ((1.0f - coef) * sourceData[p1] + coef * sourceData[p2]);
    }
}

void denoise_proc(int16_t *buffer, uint32_t buffen_len) {
    const int frame_size = 480;
    DenoiseState *st;
    st = rnnoise_create();
    int16_t patch_buffer[frame_size];
    if (st != NULL) {
        uint32_t frames = buffen_len / frame_size;
        uint32_t lastFrame = buffen_len % frame_size;
        for (int i = 0; i < frames; ++i) {
            rnnoise_process_frame(st, buffer, buffer);
            buffer += frame_size;
        }
        if (lastFrame != 0) {
            memset(patch_buffer, 0, frame_size * sizeof(int16_t));
            memcpy(patch_buffer, buffer, lastFrame * sizeof(int16_t));
            rnnoise_process_frame(st, patch_buffer, patch_buffer);
            memcpy(buffer, patch_buffer, lastFrame * sizeof(int16_t));
        }
    }
    rnnoise_destroy(st);
}

void rnnDeNoise(char *in_file, char *out_file) {
    uint32_t in_sampleRate = 0;
    uint64_t in_size = 0;
    int16_t *data_in = wavRead_int16(in_file, &in_sampleRate, &in_size);
    uint32_t out_sampleRate = 48000;
    uint32_t out_size = (uint32_t) (in_size * ((float) out_sampleRate / in_sampleRate));
    int16_t *data_out = (int16_t *) malloc(out_size * sizeof(int16_t));
    if (data_in != NULL && data_out != NULL) {
        resampleData(data_in, in_sampleRate, (uint32_t) in_size, data_out, out_sampleRate);
        denoise_proc(data_out, out_size);
        resampleData(data_out, out_sampleRate, (uint32_t) out_size, data_in, in_sampleRate);
        wavWrite_int16(out_file, data_in, in_sampleRate, (uint32_t) in_size);
        free(data_in);
        free(data_out);
    } else {
        if (data_in) free(data_in);
        if (data_out) free(data_out);
    }
}


int main(int argc, char **argv) {
    printf("Audio Noise Reduction
");
    printf("blog:http://cpuimage.cnblogs.com/
");
    printf("e-mail:gaozhihan@vip.qq.com
");
    if (argc < 2)
        return -1;

    char *in_file = argv[1];
    char drive[3];
    char dir[256];
    char fname[256];
    char ext[256];
    char out_file[1024];
    splitpath(in_file, drive, dir, fname, ext);
    sprintf(out_file, "%s%s%s_out%s", drive, dir, fname, ext);
    rnnDeNoise(in_file, out_file);
    printf("press any key to exit.
");
    getchar();
    return 0;
}

不多写注释，直接看代码吧。

 项目地址：https://github.com/cpuimage/rnnoise

示例具体流程为：

加载wav(拖放wav文件到可执行文件上)->重采样降噪->保存wav

若有其他相关问题或者需求也可以邮件联系俺探讨。

邮箱地址是: 
gaozhihan@vip.qq.com