speexsdp消除回声

这是testecho.c样例的程序。

初始化函数：

SpeexEchoState *speex_echo_state_init(int frame_size, int filter_length);
可以看头文件说明：配置frame_size贞大小10-20ms，filter_length滤波长度100-500ms

比如采样频率是16K，frame_size就是160-320，filter_length就是1600-8000

filter_length调大，达到稳定时间越长。

SpeexPreprocessState *speex_preprocess_state_init(int frame_size, int sampling_rate)

sampling_rate是实际采样频率，比如16K

使用参考

make && ./testecho 麦克输入.pcm 喇叭输出(远端传来的).pcm 消回声数据.pcm

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "speex/speex_echo.h"
#include "speex/speex_preprocess.h"
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

//主要是配置NN,TAIL
#define NN 240
#define TAIL 2400

int main(int argc, char **argv)
{
   FILE *echo_fd, *ref_fd, *e_fd;
   short echo_buf[NN], ref_buf[NN], e_buf[NN];
   SpeexEchoState *st;
   SpeexPreprocessState *den;
   int sampleRate = 16000;

   if (argc != 4)
   {
      fprintf(stderr, "testecho mic_signal.sw speaker_signal.sw output.sw\n");
      exit(1);
   }
   echo_fd = fopen(argv[2], "rb");
   ref_fd  = fopen(argv[1],  "rb");
   e_fd    = fopen(argv[3], "wb");

//    echo_fd = fopen("talk_spk.pcm", "rb");
//    ref_fd  = fopen("talk_mic.pcm",  "rb");
//    e_fd    = fopen("talk_out.pcm", "wb");

   st = speex_echo_state_init(NN, TAIL);
   den = speex_preprocess_state_init(NN, sampleRate);
   speex_echo_ctl(st, SPEEX_ECHO_SET_SAMPLING_RATE, &sampleRate);
   speex_preprocess_ctl(den, SPEEX_PREPROCESS_SET_ECHO_STATE, st);

   int tmpseti;
   float tmpsetf;
//    int echo_sppress_level = -200;
   tmpseti = 0;
   speex_preprocess_ctl(den, SPEEX_PREPROCESS_GET_DENOISE, &tmpseti);
//    speex_preprocess_ctl(den, SPEEX_PREPROCESS_GET_DENOISE, &tmpseti);
   printf("SPEEX_PREPROCESS_GET_DENOISE = %d\n", tmpseti);
   tmpseti = -40;
   speex_preprocess_ctl(den, SPEEX_PREPROCESS_SET_NOISE_SUPPRESS, &tmpseti);
   speex_preprocess_ctl(den, SPEEX_PREPROCESS_GET_NOISE_SUPPRESS, &tmpseti);
   printf("SPEEX_PREPROCESS_GET_NOISE_SUPPRESS = %d\n", tmpseti);

   tmpseti=0;
   speex_preprocess_ctl(den, SPEEX_PREPROCESS_SET_AGC, &tmpseti);
   tmpseti=sampleRate;
   speex_preprocess_ctl(den, SPEEX_PREPROCESS_SET_AGC_LEVEL, &tmpseti);
   tmpseti=1;
   speex_preprocess_ctl(den, SPEEX_PREPROCESS_SET_DEREVERB, &tmpseti);
   tmpsetf=20.0;
   speex_preprocess_ctl(den, SPEEX_PREPROCESS_SET_DEREVERB_DECAY, &tmpsetf);
   tmpsetf=20.0;
   speex_preprocess_ctl(den, SPEEX_PREPROCESS_SET_DEREVERB_LEVEL, &tmpsetf);


   tmpseti = -40;
   speex_preprocess_ctl(den, SPEEX_PREPROCESS_SET_ECHO_SUPPRESS, &tmpseti);
   speex_preprocess_ctl(den, SPEEX_PREPROCESS_GET_ECHO_SUPPRESS, &tmpseti);
   printf("SPEEX_PREPROCESS_GET_ECHO_SUPPRESS = %d\n", tmpseti);

   tmpseti = -40;
   speex_preprocess_ctl(den, SPEEX_PREPROCESS_SET_ECHO_SUPPRESS_ACTIVE, &tmpseti);
   speex_preprocess_ctl(den, SPEEX_PREPROCESS_GET_ECHO_SUPPRESS_ACTIVE, &tmpseti);
   printf("SPEEX_PREPROCESS_GET_ECHO_SUPPRESS_ACTIVE = %d\n", tmpseti);

   while (!feof(ref_fd) && !feof(echo_fd))
   {
      fread(ref_buf, sizeof(short), NN, ref_fd);
      fread(echo_buf, sizeof(short), NN, echo_fd);
      speex_echo_cancellation(st, ref_buf, echo_buf, e_buf);
      speex_preprocess_run(den, e_buf);
      fwrite(e_buf, sizeof(short), NN, e_fd);
   }
   speex_echo_state_destroy(st);
   speex_preprocess_state_destroy(den);
   fclose(e_fd);
   fclose(echo_fd);
   fclose(ref_fd);
   return 0;
}

效果（工具Audacity）：