Voice Recording/Playing back using simple classes

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Introduction

Most of us are familiar with at least one multimedia recording software. Windows has one of the simplest ones: Sound Recorder. In this article I want to introduce some simple but useful classes for recording/playing back of voice that wrap the WAVE APIs.

WAVE APIs

Here is the list of all the Wave APIs that I have used:

Recording

waveInOpen Open the Wave device for recording. waveInPrepareHeader Prepare the Wave header for recording. waveInAddBuffer Add buffer waveInStart Start recording. Recorded data will be saved in a specified buffer. waveInUnprepareHeader After finishing the record process, should un-prepare Wave header. waveInClose Close the recording device.

Playing

waveOutOpen Open the Wave device for playing. waveOutPrepareHeader Prepare the Wave header for playing. waveOutWrite Play the buffer. waveOutUnprepareHeader Un-prepare the Wave header. waveOutClose Close the playing device.

As you can see, working with these APIs are straightforward but if you want to skip them and simply do a copy/paste code in your project, my classes are for you.

Here is the definition of the classes:

Collapse

class CVoiceBase  {public:        CString m_result;    MMRESULT res;    enum     {        SPS_8K=8000,        SPS_11K=11025,        SPS_22K=22050,        SPS_44K=44100    };    enum    {        CH_MONO=1,        CH_STEREO=2    };    char* buffer;    WAVEHDR WaveHeader;    WAVEFORMATEX PCMfmt;    void SetFormat(DWORD nSamplesPerSec,              WORD  wBitsPerSample,WORD  nChannels);    BOOL CopyBuffer(LPVOID lpBuffer, DWORD ntime);    CString GetLastError();    void GetMMResult(MMRESULT res);    void DestroyBuffer();    BOOL PrepareBuffer(DWORD ntime);        CVoiceBase();    virtual ~CVoiceBase();};class CVoiceRecording : public CVoiceBase  {public:    void RecordFinished();    BOOL IsOpen();    BOOL Close();    BOOL Open();        BOOL Record();        HWAVEIN hWaveIn;        CVoiceRecording();    virtual ~CVoiceRecording();};class CVoicePlaying : public CVoiceBase  {public:    void PlayFinished();    BOOL IsOpen();    BOOL Close();    BOOL Open();    BOOL Play();    HWAVEOUT hWaveOut;    CVoicePlaying();    virtual ~CVoicePlaying();};

Also, for notifying of events, such as finishing recording/playing, I have used two callback functions:

BOOL CALLBACK VoiceWaveInProc(HWAVEIN hwi,                   UINT uMsg,                     DWORD dwInstance,              DWORD dwParam1,                DWORD dwParam2                     );BOOL CALLBACK VoiceWaveOutProc(HWAVEOUT hwi,                   UINT uMsg,                     DWORD dwInstance,              DWORD dwParam1,                DWORD dwParam2                     );

Example

Just declare two variables of type CVoiceRecording and CVoicePlaying. Use SetFormat, PrepareBuffer, Open and Record or Play member functions to work with them:

CVoiceRecording m_Record;CVoicePlaying m_Play;m_Record.PrepareBuffer(10);    //prepare buffer for recording 10 seconds.m_Record.Open();    m_Play.PrepareBuffer(10);    //prepare buffer for playing of 10 seconds of datam_Play.Open();    if (m_Record.IsOpen()){    m_Record.Record();}//after finishing the record scenario,//play the buffer, first copy recorded buffer to m_Play bufferm_Play.CopyBuffer(m_Record.buffer, 10);        if (m_Play.IsOpen()){    m_Play.Play();}

Enjoy!

License

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About the Authors

A. Riazi


I was born in Shiraz, a very beautiful famous city in Iran. I started programming when I was 12 years old with GWBASIC. Since now, I worked with various programming languages from Basic, Foxpro, C/C++, Visual Basic, Pascal to MATLAB and now Visual C++.
I graduated from Iran University of Science & Technology in Communication Eng., and now work as a system programmer for a telecommunication industry.
I wrote several programs and drivers for Synthesizers, Power Amplifiers, GPIB, GPS devices, Radio cards, Data Acqusition cards and so many related devices.
I'm author of several books like Learning C (primary and advanced), Learning Visual Basic, API application for VB, Teach Yourself Object Oriented Programming (OOP) and etc.
I'm winner of January, May, August 2003 and April 2005 best article of month competetion, my articles are:

• Add GPS Support to your Desktop
  
• Solving Engineering Problem Using MATLAB C API
• Text2PDF
• Scan2PDF

You can see list of my articles, by clicking here

Occupation: Software Developer (Senior) Company: Misbah3Com Location: Iran, Islamic Republic Of
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Occupation: Web Developer Location: Iran, Islamic Republic Of