AMR格式语音采集/编码/转码/解码/播放

1、opencore-amr源码下载

https://sourceforge.net/projects/opencore-amr/files/opencore-amr/

2、opencore-amr编译

交叉编译到arm平台

./configure --host=arm-linux-gnueabihf --prefix='/home/dong/pocdemo/opencore-amr-0.1.3/arm'

make

make install

3、opencore-amr的应用

1) opencore-amr静态库的使用
arm-linux-gnueabihf-g++ -o demo demo.c -I ./opencore-amr/include/opencore-amrnb libpoc.a ./opencore-amr/lib/libopencore-amrnb.a -lpthread

2) opencore-amr动态库的使用
arm-linux-gnueabihf-g++ -o demo demo.c -I ./opencore-amr/include/opencore-amrnb -L ./ -lpoc -L ./opencore-amr/lib -lopencore-amrnb -lpthread

3) opencore-amr静态库动态库混合的使用
arm-linux-gnueabihf-g++ -o demo demo.c -I ./opencore-amr/include/opencore-amrnb -L ./ -lpoc ./opencore-amr/lib/libopencore-amrnb.a -lpthread

4、源码包里的 opencore-amr/test/amrnb-enc-sine.c

编码一段正玄波

/* ------------------------------------------------------------------
 * Copyright (C) 2009 Martin Storsjo
 *
 * 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.
 * -------------------------------------------------------------------
 */

#include <stdio.h>
#include <stdint.h>
#include <math.h>
#include <interf_enc.h>

int main(int argc, char *argv[]) {
    int i, j;
    void* amr;
    FILE* out;
    int sample_pos = ;

    if (argc < ) {
        fprintf(stderr, "%s out.amr\n", argv[]);
        return ;
    }

    amr = Encoder_Interface_init();
    out = fopen(argv[], "wb");
    if (!out) {
        perror(argv[]);
        return ;
    }

    fwrite("#!AMR\n", , , out);
    for (i = ; i < ; i++) {
        short buf[];
        uint8_t outbuf[];
        int n;
        for (j = ; j < ; j++) {
            buf[j] = *sin(**3.141592654*sample_pos/);
            sample_pos++;
        }
        n = Encoder_Interface_Encode(amr, MR475, buf, outbuf, );
        fwrite(outbuf, , n, out);
    }
    fclose(out);
    Encoder_Interface_exit(amr);

    return ;
}

arm-linux-gnueabihf-gcc -o amrnb-enc-sine amrnb-enc-sine.c -I ./opencore-amr/include/opencore-amrnb ./opencore-amr/lib/libopencore-amrnb.a

5、PCM与AMR互转

https://github.com/gansidui/pcm_amr_codec

dong@ubuntu:~/amr/example$ tree
.
├── build_example_amr2pcm_arm.sh
├── build_example_pcm2amr_x86.sh
├── codec
│   ├── amrnb.c
│   ├── amrnb.h
│   ├── audio_format_convert.c
│   ├── audio_format_convert.h
│   └── bs.h
├── dec
├── example_amr2pcm.c
├── example_pcm2amr.c
├── libopencore-amrnb.so.0
├── opencore-amr
│   ├── include
│   │   ├── opencore-amrnb
│   │   │   ├── interf_dec.h
│   │   │   └── interf_enc.h
│   │   └── opencore-amrwb
│   │       ├── dec_if.h
│   │       └── if_rom.h
│   └── lib
│       ├── libopencore-amrnb.a
│       ├── libopencore-amrnb.la
│       ├── libopencore-amrnb.so -> libopencore-amrnb.so.0.0.3
│       ├── libopencore-amrnb.so.0 -> libopencore-amrnb.so.0.0.3
│       ├── libopencore-amrnb.so.0.0.3
│       ├── libopencore-amrwb.a
│       ├── libopencore-amrwb.la
│       ├── libopencore-amrwb.so -> libopencore-amrwb.so.0.0.3
│       ├── libopencore-amrwb.so.0 -> libopencore-amrwb.so.0.0.3
│       ├── libopencore-amrwb.so.0.0.3
│       └── pkgconfig
│           ├── opencore-amrnb.pc
│           └── opencore-amrwb.pc
├── run_dec.sh
├── run_enc.sh
├── test.amr
└── test.amr.pcm

1) gcc可以直接编译

#arm-linux-gnueabihf-gcc example_amr2pcm.c ./codec/audio_format_convert.c ./codec/amrnb.c ./codec/bs.h -o dec -I'./opencore-amr/include/opencore-amrnb' -I'./opencore-amr/include/opencore-amrwb' -I'./codec' ./opencore-amr/lib/libopencore-amrnb.a ./opencore-amr/lib/libopencore-amrwb.a

2) g++和gcc编译需要一点小改动

更改audio_format_convert.h

//#ifdef __cplusplus
//extern "C" {
//#endif

...

...

//#ifdef __cplusplus
//}
//#endif

amrnb.c的第294和368行

int ret = Encoder_Interface_Encode(amrnb_enc, MR475, &samples[offset / sizeof (int16_t)], tmp, amrnb_dtx);

参数mode改成MR475

arm-linux-gnueabihf-g++ example_amr2pcm.c ./codec/audio_format_convert.c ./codec/amrnb.c ./codec/bs.h -o dec -I'./opencore-amr/include/opencore-amrnb' -I'./opencore-amr/include/opencore-amrwb' -I'./codec' ./opencore-amr/lib/libopencore-amrnb.a ./opencore-amr/lib/libopencore-amrwb.a

我的项目整理下编译指令 build.sh

arm-linux-gnueabihf-g++ -o poc_client \
poc_client.c \
./codec/audio_format_convert.c \
./codec/amrnb.c \
./codec/bs.h \
./fifo/app_fifo.c \
./fifo/app_fifo.h \
./list/list.c \
./list/list.h \
-I'./opencore-amr/include/opencore-amrnb' \
-I'./opencore-amr/include/opencore-amrwb' \
-I'./codec' \
./opencore-amr/lib/libopencore-amrnb.a \
./opencore-amr/lib/libopencore-amrwb.a \
./poc/libpoc.a \
-I ./alsa/include -L ./alsa/lib -lasound \
-lpthread

6、alsa播放pcm音频

播放pcm文件

/**alsa play test
*ALSA用户空间编译，ALSA驱动的声卡在用户空间，不宜直接使用
*文件接口中，而应使用alsa-lib
*打开---->设置参数--->读写音频数据 ALSA全部使用alsa-lib中的API
*交叉编译
*export LD_LIBRARY_PATH=$PWD:$LD_LIBRARY_PATH
*arm-linux-gcc -o alsa_play alsa_play_test.c -L. -lasound
*需要交叉编译后的libasound.so库的支持
*
*/
#include <stdio.h>
#include <stdlib.h>
#include "alsa/asoundlib.h"

int main(int argc, char *argv[])
{
    int i;
    int ret;
    int buf[];
    unsigned int val;
    int dir=;
    char *buffer;
    int size;
    snd_pcm_uframes_t frames;
    snd_pcm_uframes_t periodsize;
    snd_pcm_t *playback_handle;//PCM设备句柄pcm.h
    snd_pcm_hw_params_t *hw_params;//硬件信息和PCM流配置
    if (argc != ) {
        printf("error: alsa_play_test [music name]\n");
        exit();
    }
    printf("play song %s by wolf\n", argv[]);
    FILE *fp = fopen(argv[], "rb");
    if(fp == NULL)
    return ;
    fseek(fp, , SEEK_SET);

    //1. 打开PCM，最后一个参数为0意味着标准配置
    ret = snd_pcm_open(&playback_handle, "default", SND_PCM_STREAM_PLAYBACK, );
    if (ret < ) {
        perror("snd_pcm_open");
        exit();
    }

    //2. 分配snd_pcm_hw_params_t结构体
    ret = snd_pcm_hw_params_malloc(&hw_params);
    if (ret < ) {
        perror("snd_pcm_hw_params_malloc");
        exit();
    }
    //3. 初始化hw_params
    ret = snd_pcm_hw_params_any(playback_handle, hw_params);
    if (ret < ) {
        perror("snd_pcm_hw_params_any");
        exit();
    }
    //4. 初始化访问权限
    ret = snd_pcm_hw_params_set_access(playback_handle, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED);
    if (ret < ) {
        perror("snd_pcm_hw_params_set_access");
        exit();
    }
    //5. 初始化采样格式SND_PCM_FORMAT_U8,8位
    ret = snd_pcm_hw_params_set_format(playback_handle, hw_params, SND_PCM_FORMAT_U8);
    if (ret < ) {
        perror("snd_pcm_hw_params_set_format");
        exit();
    }
    //6. 设置采样率，如果硬件不支持我们设置的采样率，将使用最接近的
    //val = 44100,有些录音采样频率固定为8KHz

    val = ;
    ret = snd_pcm_hw_params_set_rate_near(playback_handle, hw_params, &val, &dir);
    if (ret < ) {
        perror("snd_pcm_hw_params_set_rate_near");
        exit();
    }
    //7. 设置通道数量
    ret = snd_pcm_hw_params_set_channels(playback_handle, hw_params, );
    if (ret < ) {
        perror("snd_pcm_hw_params_set_channels");
        exit();
    }

    /* Set period size to 32 frames. */
    frames = ;
    periodsize = frames * ;
    ret = snd_pcm_hw_params_set_buffer_size_near(playback_handle, hw_params, &periodsize);
    if (ret < )
    {
         printf("Unable to set buffer size %li : %s\n", frames * , snd_strerror(ret));

    }
          periodsize /= ;

    ret = snd_pcm_hw_params_set_period_size_near(playback_handle, hw_params, &periodsize, );
    if (ret < )
    {
        printf("Unable to set period size %li : %s\n", periodsize,  snd_strerror(ret));
    }

    //8. 设置hw_params
    ret = snd_pcm_hw_params(playback_handle, hw_params);
    if (ret < ) {
        perror("snd_pcm_hw_params");
        exit();
    }

     /* Use a buffer large enough to hold one period */
    snd_pcm_hw_params_get_period_size(hw_params, &frames, &dir);

    size = frames * ; /* 2 bytes/sample, 2 channels */
    buffer = (char *) malloc(size);
    fprintf(stderr,
            "size = %d\n",
            size);

    while ()
    {
        ret = fread(buffer, , size, fp);
        if(ret == )
        {
              fprintf(stderr, "end of file on input\n");
              break;
        }
        else if (ret != size)
        {
        }
        //9. 写音频数据到PCM设备
        while(ret = snd_pcm_writei(playback_handle, buffer, frames)<)
        {
            usleep();
            if (ret == -EPIPE)
            {
                  /* EPIPE means underrun */
                  fprintf(stderr, "underrun occurred\n");
                  //完成硬件参数设置，使设备准备好
                  snd_pcm_prepare(playback_handle);
            }
            else if (ret < )
            {
                  fprintf(stderr,
                      "error from writei: %s\n",
                      snd_strerror(ret));
            }
        }

    }
    //10. 关闭PCM设备句柄
    snd_pcm_close(playback_handle);

    return ;
}

arm-linux-gnueabihf-gcc -o test test.c -I ./alsa/include -L ./alsa/lib -lasound -lpthread

./test file.pcm

播放pcm缓存

    #include <alsa/asoundlib.h>

    int main()
    {
        int ret;
        snd_pcm_t *pcm_handle;
        snd_pcm_stream_t stream = SND_PCM_STREAM_PLAYBACK;
        snd_pcm_hw_params_t *hwparams;
        char *pcm_name;

        pcm_name = strdup("plughw:0,0");

        snd_pcm_hw_params_alloca(&hwparams);

        ret = snd_pcm_open(&pcm_handle, pcm_name, stream, );
        if (ret < ) {
            printf("snd_pcm_open failed\n");
            return(-);
        }

        ret = snd_pcm_hw_params_any(pcm_handle, hwparams);
        if (ret < ) {
            printf("snd_pcm_hw_params_any failed\n");
            return(-);
        }

        int rate = ;
        int exact_rate;
        int dir;
        int periods = ;
        snd_pcm_uframes_t periodsize = ;

        ret = snd_pcm_hw_params_set_access(pcm_handle, hwparams,
                SND_PCM_ACCESS_RW_INTERLEAVED);
        if (ret < ) {
            printf("snd_pcm_hw_params_set_access failed\n");
            return(-);
        }

        ret = snd_pcm_hw_params_set_format(pcm_handle, hwparams,
                SND_PCM_FORMAT_S16_LE);
        if (ret < ) {
            printf("snd_pcm_hw_params_set_format failed\n");
            return(-);
        }

        exact_rate = rate;
        ret = snd_pcm_hw_params_set_rate_near(pcm_handle, hwparams,
                &exact_rate, );
        if (ret < ) {
            printf("snd_pcm_hw_params_set_rate_near failed\n");
            return(-);
        }
        if (rate != exact_rate) {
            printf("The rate %d Hz is not supported by your hardware\n"
                    "==> Using %d Hz instead\n", rate, exact_rate);
        }

        ret = snd_pcm_hw_params_set_channels(pcm_handle, hwparams, );
        if (ret < ) {
            printf("snd_pcm_hw_params_set_channels failed\n");
            return(-);
        }
/*
        ret = snd_pcm_hw_params_set_periods(pcm_handle, hwparams, periods, 0);
        if (ret < 0) {
            printf("snd_pcm_hw_params_set_periods failed\n");
            return(-1);
        }
*/
        ret = snd_pcm_hw_params_set_buffer_size(pcm_handle, hwparams,
                (periodsize * periods) >> );
        if (ret < ) {
            printf("snd_pcm_hw_params_set_buffer_size failed\n");
            return(-);
        }

        ret = snd_pcm_hw_params(pcm_handle, hwparams);
        if (ret < ) {
            printf("snd_pcm_hw_params failed\n");
            return(-);
        }

        unsigned char *data;
        int l1, l2;
        short s1, s2;
        int frames;

        data = malloc(periodsize);
        frames = periodsize >> ;

        for (l1 = ; l1 < ; l1++) {
            for (l2 = ; l2 < frames; l2++) {
                s1 = (l2 % ) *  - ;
                s2 = (l2 % ) *  - ;
                data[*l2] = (unsigned char)s1;
                data[*l2+] = s1 >> ;
                data[*l2+] = (unsigned char)s2;
                data[*l2+] = s2 >> ;
            }
            while ((ret = snd_pcm_writei(pcm_handle, data, frames)) < ) {
                snd_pcm_prepare(pcm_handle);
                printf("<<<<<<<<<<<<<<Buffer Underrun>>>>>>>>>>>>\n");
            }
        }

        snd_pcm_drop(pcm_handle);
        snd_pcm_drain(pcm_handle);

        return ;
    }

arm-linux-gnueabihf-gcc -o test test.c -I ./alsa/include -L ./alsa/lib -lasound -lpthread

./test

7、alsa采集pcm音频

采集pcm到缓存/文件

/*
read from the default PCM device and writes to standard output for 5 seconds of data
*/

#define ALSA_PCM_NEW_HW_PARAMS_API

#include <alsa/asoundlib.h>

snd_pcm_t * handle;
snd_pcm_hw_params_t * params;
snd_pcm_uframes_t frames;
char * buffer;
unsigned int val;

int alsa_capture_init()
{
    int dir;
    int rc;    

   /* open PCM device for recording (capture). */
   rc = snd_pcm_open(&handle, "default",SND_PCM_STREAM_CAPTURE,);
   if( rc <  )
   {
        return -;
   }
   /* allocate a hardware parameters object */
   snd_pcm_hw_params_alloca(&params);
   /* fill it with default values. */
   snd_pcm_hw_params_any(handle,params);
   /* set the desired hardware parameters */
   snd_pcm_hw_params_set_access(handle,params,
                                SND_PCM_ACCESS_RW_INTERLEAVED);
   /* signed 16-bit little-endian format */
   snd_pcm_hw_params_set_format(handle,params,
                                SND_PCM_FORMAT_S16_LE);
   /* two channels(stereo) */
   snd_pcm_hw_params_set_channels(handle,params,);
   /* sampling rate */
   val = ;
   snd_pcm_hw_params_set_rate_near(handle,params,&val,&dir);
   /* set period size */
   frames = ;
   snd_pcm_hw_params_set_period_size_near(handle,params,&frames,&dir);
   /* write parameters to the driver */
   rc = snd_pcm_hw_params(handle,params);
   if ( rc <  )
   {
        return -;
   }
   /* use a buffer large enough to hold one period */
   snd_pcm_hw_params_get_period_size(params,&frames,&dir);

   /* loop for 5 seconds */
   snd_pcm_hw_params_get_period_time(params, &val, &dir);

   return ;
}

int main()
{
   long loops;
   int ret;
   int size;
   FILE * out_fd;
   out_fd = fopen("out_pcm.raw","wb+");    

   alsa_capture_init();
   loops =  / val;

   /* 2 bytes/sample, 1 channels */
   size = frames * ;
   buffer = ( char * ) malloc(size);

   while( loops >  )
   {
       loops--;
       ret = snd_pcm_readi(handle,buffer,frames);
       if ( ret == -EPIPE )
       {
          /* EPIPE means overrun */
          fprintf(stderr,"overrun occured\n");
          snd_pcm_prepare(handle);
       }
       else if ( ret <  )
       {
          fprintf(stderr,"error from read: %s\n",
                  snd_strerror(ret));
       }
       else if ( ret != (int)frames)
       {
          fprintf(stderr,"short read, read %d frames\n",ret);
       }

       ret = fwrite(buffer, , size, out_fd);
       // ret = write(1, buffer, size);
       if ( ret != size )
       {
          fprintf(stderr,"short write: wrote %d bytes\n",ret);
       }
   }
   snd_pcm_drain(handle);
   snd_pcm_close(handle);
   free(buffer);
   fclose(out_fd);
}

arm-linux-gnueabihf-gcc -o test test.c -I ./alsa/include -L ./alsa/lib -lasound -lpthread

./test

8、综合应用实例

采集一段PCM格式语音数据 ，转码成AMR格式然后发送至rtp网络

#if 1
           int i;
           char outbuf[PCM_DATA_LENGTH];

           for (i = ; i < *; i++) {
               ret = snd_pcm_readi(handle,buffer,frames);
               if ( ret == -EPIPE )
               {
                  printf("overrun occured\n");
                  snd_pcm_prepare(handle);
               }               

                buffer_pcm2amr_encode((char*)buffer, PCM_DATA_LENGTH, outbuf);

                //n = Encoder_Interface_Encode(amr, MR795, buf, outbuf, 0);
                amrFrame->m_nFrameLen = ;
                amrFrame->m_nFrameCount = ;
                amrFrame->m_pFrame = outbuf;
                NxZDPttAccess_AmrFrame(snCurCallSessionId, amrFrame);
            }

#else
            //------------------------------------
            //sin data test
            int i, j;
            int sample_pos = ;

            for (i = ; i < ; i++) {
                short buf[];
                char outbuf[];
                int n;
                for (j = ; j < ; j++) {
                    buf[j] = *sin(**3.141592654*sample_pos/);
                    sample_pos++;
                }
                buffer_pcm2amr_encode((char*)buf, , outbuf);

                //n = Encoder_Interface_Encode(amr, MR515, buf, outbuf, 0);
                amrFrame->m_nFrameLen = ;
                amrFrame->m_nFrameCount = ;
                amrFrame->m_pFrame = outbuf;
                NxZDPttAccess_AmrFrame(snCurCallSessionId, amrFrame);
            }
            //-------------------------------------
#endif

接收一段AMR格式语音数据，转码成PCM格式，然后写入声卡播放

#if 1
            int i;
            for (i = ; i < pAmrFrame->m_nFrameCount; i++) {
                int ret = buffer_amr2pcm_decode(pAmrFrame->m_pFrame + i*pAmrFrame->m_nFrameLen, pAmrFrame->m_nFrameLen, pcm_data_buf);
                if(ret > ){
                    if((ret = snd_pcm_writei(pcm_handle, pcm_data_buf, PCM_DATA_LENGTH/)) < )     {
                        snd_pcm_prepare(pcm_handle);
                        printf("<<<<<<<<<<<<<<Buffer Underrun>>>>>>>>>>>>\n");
                    }
                }
            }

#else
            unsigned char *data;
            int l1, l2;
            short s1, s2;
            int frames;
            int periodsize = ;
            data = (unsigned char*)malloc(periodsize);
            frames = periodsize >> ;

            for (l1 = ; l1 < ; l1++) {
                for (l2 = ; l2 < frames; l2++) {
                    s1 = (l2 % ) *  - ;
                    s2 = (l2 % ) *  - ;
                    data[*l2] = (unsigned char)s1;
                    data[*l2+] = s1 >> ;
                    data[*l2+] = (unsigned char)s2;
                    data[*l2+] = s2 >> ;
                }
                if((ret = snd_pcm_writei(pcm_handle, data, frames)) < ) {
                    snd_pcm_prepare(pcm_handle);
                    printf("<<<<<<<<<<<<<<Buffer Underrun>>>>>>>>>>>>\n");
                }
            }
#endif

9、拓展

tinyalsa做了很多琐事，省了不少时间，感谢作者。

https://github.com/tinyalsa/tinyalsa

generation-sine-wave

https://github.com/ichgw/generation-sine-wave

https://github.com/moutend/getSineWave

https://github.com/munnellg/SineWave