How to obtain audio recordings using WINDOWSAPI _c language

The example of this article introduces the method of using winmm.h to obtain the audio stream, the following steps are as follows:

First, you need to include the following reference objects

#include <Windows.h>
#include "mmsystem.h"
#pragma comment (lib, "Winmm.lib")

Second, the acquisition of audio needs to call 7 functions

1. Waveingetnumdevs: Returns the number of waveform sound input devices that are ready in the system

UINT Waveingetnumdevs (VOID);

2. Waveingetdevcaps: Check the characteristics of the specified waveform input device

Mmresult waveingetdevcaps ( 
 uint_ptr   Udeviceid, 
 lpwaveincaps Pwic, UINT cbwic    
);
Udeviceid audio input device identification, or a handle to an open audio input device.  personally think that if you get multiple devices in the previous step, you can identify each device with an index.  
//pwic A pointer to a WAVEINCAPS structure that contains the audio characteristics of the device.
//cbwic waveincaps The size of the structure, the use of sizeof can be.
The result of the//mmresult function execution//  mmsyserr_noerror indicates that the execution succeeded
//Mmsyserr_baddeviceid index is out of  bounds 
//  Mmsyserr_nodriver devices 
//Mmsyserr_nomem not ready to  allocate or lock memory

Introduce the meaning of Waveincaps structure:

typedef struct { 
  WORD   wmid;        Audio device manufacturer-defined driver identification
  WORD   wpid;        Audio input Equipment Product identification
  mmversion vdriverversion;    Driver version number
  TCHAR   szpname[maxpnamelen];//manufacturer name
  DWORD   dwformats;      Supported formats, see MSDN
  WORD   wchannels;      Number of channels supported
  WORD   wReserved1;      Retention parameters
} waveincaps;

3. Waveinopen: Open the specified audio input device for recording

Mmresult Waveinopen (
 lphwavein    phwi,        ///Receive a pointer to the Hwavein structure identified by an open audio input device uint_ptr    Udeviceid,      //Specify a device ID that needs to be opened. You can use Wave_mapper to select a device
 to record in the specified recording format Lpwaveformatex pwfx,/        /A required format for recording the WaveFormatEx pointer 
 dword_ptr dwcallback,//pointing to    a callback function, event handle, A window handle, thread identification, and processing of a recording event.
 Dword_ptr   dwcallbackinstance,//pass to the callback mechanism parameter
 DWORD     fdwopen      //Open device's method ID, specifying the type of callback. See also CSDN
);

Introduce the meaning of WAVEFORMATEX structure:

typedef struct { 
  WORD wformattag;    Waveform sound format, mono dual channel using WAVE_FORMAT_PCM. When included in the waveformatextensible structure, use wave_format_extensible.
  WORD nchannels;    Channel quantity
  DWORD nsamplespersec;  Sampling rate. When wFormatTag is WAVE_FORMAT_PCM, there are 8.0khz,11.025khz,22.05khz, and 44.1kHz.
  DWORD navgbytespersec;  Number of bytes sampled per second. WORD nblockalign is computed by nsamplespersec * nchannels * WBITSPERSAMPLE/8
  ;    The number of bytes per sample. Calculate WORD wbitspersample by nchannels * WBITSPERSAMPLE/8
  ;  Number of sampling bits. When wFormatTag is WAVE_FORMAT_PCM, it is 8 or
  WORD cbsize;      When wFormatTag is WAVE_FORMAT_PCM, this parameter is ignored
} WaveFormatEx;

Describes the Dwcallback callback function format:

void CALLBACK Waveinproc (
 hwavein hwi,     //callback device handle for this function
 UINT umsg,      //waveform sound input information, identity off (wim_close), buffer full (Wim_data), open (Wim_open).
 Dword_ptr dwinstance,//user specified in Waveinopen data
 dword_ptr dwParam1,  //(LPWAVEHDR) dwParam1, user specified buffer
 Dword_ptr dwParam2   
);

4. Waveinprepareheader: Prepare a buffer for the audio input device

Mmresult Waveinprepareheader (
 hwavein hwi,  //audio input device handle
 LPWAVEHDR pwh,//pointer to the WAVEHDR structure, identifying the prepared buffer
 UINT CBWH    //wavehdr the size of the structure, the use of sizeof can be
);

Introduction to WAVEHDR Structure:

typedef struct WAVEHDR_TAG { 
  LPSTR   lpdata;     Buffer DWORD in waveform format   dwbufferlength;//Buffer size
  DWORD   dwbytesrecorded;//How much data is currently stored
  Dword_ PTR Dwuser;     User Data
  DWORD   dwflags;      The information provided for the buffer, using the whdr_prepared DWORD dwloops in the Waveinprepareheader function   ;     The output is used, identifies the number of playback
  struct Wavehdr_tag * lpnext;//reserved
  dword_ptr reserved;     Reserved
} wavehdr, *LPWAVEHDR; 

5. Waveinaddbuffer: The buffer is sent to the device, and if the buffer fills up, it does not work. (Parameter ditto)

Mmresult Waveinaddbuffer (
 hwavein hwi, 
 lpwavehdr pwh, UINT CBWH 
); 

6. Waveinstart: Start recording

Mmresult Waveinstart (
 hwavein hwi//device handle
);

7. Waveinclose: Turn off the equipment

Mresult waveinclose (
 hwavein hwi//device handle
);

Three, the complete example code is as follows:

RUN.C file #include <Windows.h> #include <stdio.h> #include "mmsystem.h" #pragma comment (lib, "Winmm.lib") vo
ID Playmusi ();
void Waveinitformat (Lpwaveformatex m_waveformat, WORD nch,dword nsamplerate,word bitspersample);
DWORD CALLBACK Miccallback (Hwavein Hwavein, UINT umsg, DWORD dwinstance, DWORD dwParam1, DWORD dwParam2);

void Recordwave ();
 void Main () {//playmusi ();
 Recordwave ();
while (1);

 void Recordwave () {int count = Waveingetnumdevs ();//1 printf ("\ n audio Input quantity:%d\n", count);
 Waveincaps Waveincaps; Mmresult Mmresult = Waveingetdevcaps (0,&waveincaps,sizeof (waveincaps))//2 printf ("\ n audio input device:%s\n",

 Waveincaps.szpname);
 if (mmsyserr_noerror==mmresult) {Hwavein phwi;
 WaveFormatEx pwfx;
 Waveinitformat (&pwfx,1,8000,8);
 printf ("\ n request to open audio input device");
 printf ("\ n sampling parameters: Mono 8kHz 8bit\n"); Mmresult=waveinopen (&AMP;PHWI,WAVE_MAPPER,&AMP;PWFX, (DWORD) (miccallback), null,callback_function);//3 if (
  Mmsyserr_noerror==mmresult) {WAVEHDR pwh1;
 Char buffer1[10240]; Pwh1.lpdata=buffer1;
  pwh1.dwbufferlength=10240;
  Pwh1.dwuser=1;
  pwh1.dwflags=0;

  Mmresult=waveinprepareheader (phwi,&pwh1,sizeof (WAVEHDR));//4 printf ("Prepare buffer 1");
  WAVEHDR Pwh2;
  Char buffer2[10240];
  Pwh2.lpdata=buffer2;
  pwh2.dwbufferlength=10240;
  pwh2.dwuser=2;
  pwh2.dwflags=0;

  Mmresult=waveinprepareheader (phwi,&pwh2,sizeof (WAVEHDR));//4 printf ("Prepare buffer 2\n"); if (Mmsyserr_noerror==mmresult) {Mmresult=waveinaddbuffer (phwi,&pwh1,sizeof (WAVEHDR));//5 printf ("\
  n Add buffer 1 to the audio input device ");

  Mmresult=waveinaddbuffer (phwi,&pwh2,sizeof (WAVEHDR));//5 printf ("\ n Add buffer 2 to the audio input device \ n");
  if (Mmsyserr_noerror==mmresult) {Mmresult=waveinstart (PHWI);//6 printf ("\ n request to start recording \ n");
 "}}}} DWORD CALLBACK Miccallback (Hwavein Hwavein, UINT umsg, DWORD dwinstance, DWORD dwParam1, DWORD dwParam2) {
  Switch (umsg) {case wim_open:printf ("\ n device already open ... \ n");
 
 Break
  Case wim_data:printf ("\ n buffer%d full ... \ n", ((LPWAVEHDR) dwParam1)->dwuser); WaveinaddbuFfer (Hwavein, (LPWAVEHDR) dwParam1, sizeof (WAVEHDR));
 
 Break
  Case wim_close:printf ("\ n device is closed ... \ n");
 Break
 Default:break;
return 0; } void Waveinitformat (Lpwaveformatex m_waveformat, WORD nch,dword nsamplerate,word bitspersample) {m_WaveFormat->
 wFormatTag = WAVE_FORMAT_PCM;
 M_waveformat->nchannels = nch;
 M_waveformat->nsamplespersec = nsamplerate;
 m_waveformat->navgbytespersec = nsamplerate * nch * BITSPERSAMPLE/8;
 M_waveformat->nblockalign = M_waveformat->nchannels * BITSPERSAMPLE/8;
 M_waveformat->wbitspersample = BitsPerSample;
m_waveformat->cbsize = 0; void Playmusi () {int error = mcisendstring ("Open c:\\users\\angel\\desktop\\ how much love can be redone. mp3 Alias mydivece", NULL, 0, NUL
 L);

 if (Error = = 0) {mcisendstring ("play mydivece", NULL, 0, NULL);/playing}}