mmaudio.h

实时监控

#ifndef _MM_AUDIO_H
#define _MM_AUDIO_H

#include "mmsystem.h"
#include "atlbase.h"
#pragma comment(lib,"winmm.lib")

//////////////////////////////////////////////////////////////////////////

class mmaudio
{
	enum {block = 2048};
	enum {buffer_count=2};

	HWAVEOUT h;
	int ch;
	int sr;
	int bits;
	WAVEFORMATEX wfx;
	WAVEHDR wh[buffer_count];

	bool used[buffer_count];
	byte* buffers[buffer_count];

//	volatile bool playing;
	HANDLE evt;

	CComAutoCriticalSection cs;

	int handle;
	void unprepare()
	{
		//while( playing )
		//	Sleep(1);
		
		MMRESULT res = 0;
		//if( wh[handle].dwFlags & WHDR_PREPARED )
		res = waveOutPrepareHeader(h, &wh[handle], sizeof(WAVEHDR));
	}
	bool play()
	{
		MMRESULT res = 0;
		
		res = waveOutPrepareHeader(h, &wh[handle], sizeof(WAVEHDR));
		
		MMSYSERR_INVALHANDLE;
		WAVERR_UNPREPARED;
		
		//WaitForSingleObject(evt, INFINITE);
		res = waveOutWrite(h, &wh[handle], sizeof(WAVEHDR));
		
		used[handle] = false;
		
		if( res )
			TRACE("[res]: %lx\n", res);
		
		//		handle++;
		//		handle %= buffer_count;
		
		return true;
	}
	byte* get_buffer() 
	{
		cs.Lock();
		for( int i=0; i<buffer_count; i++ )
			if( !used[i] )
			{
				handle = i;
				used[i] = true;
				
				cs.Unlock();
				return buffers[i];
			}
			cs.Unlock();
			return NULL;
	}
public:
	mmaudio():h(NULL), evt(NULL), handle(0)
	{
		memset(buffers, 0, buffer_count*sizeof(byte*));
		memset(used, false, buffer_count*sizeof(byte));
	}
	~mmaudio(){destroy();}
	
	operator HWAVEOUT()
	{
		return h;
	}

	void destroy()
	{
		if( h )
		{
			waveOutReset(h);
			waveOutClose(h);
			h = NULL;
		}
		if( evt )
		{
			CloseHandle(evt);
			evt = NULL;
		}
		for( int i=0; i<buffer_count; i++ )
		{
			delete[] buffers[i];
			buffers[i] = NULL;
		}
		handle = 0;
	}
	bool create(int channels, int sample_rate, WORD bits_per_sample)
	{
		if( !evt )
			evt = CreateEvent(NULL, TRUE, FALSE, NULL);

		ch = channels;
		sr = sample_rate;
		bits = bits_per_sample;
		
		MMRESULT res = 0;
		res = waveOutGetNumDevs();
		if( res == 0 )
			return false;	// no audio device found
		
		WAVEOUTCAPS caps;
		res = waveOutGetDevCaps(0, &caps, sizeof(WAVEOUTCAPS));
		
		ZeroMemory(&wfx, sizeof(WAVEFORMATEX));
		wfx.cbSize = sizeof(wfx);
		wfx.wFormatTag = WAVE_FORMAT_PCM;
		wfx.nChannels = channels;
		wfx.nSamplesPerSec = sample_rate;
		wfx.wBitsPerSample = bits_per_sample;
		wfx.nAvgBytesPerSec = sample_rate * channels * bits_per_sample/8;  
		wfx.nBlockAlign = channels * bits_per_sample/8; 
		
		res = waveOutOpen(&h, 0, &wfx, (DWORD)evt, (DWORD)this, CALLBACK_EVENT);
		if( res )
			return false;
		
		for( int i=0; i<buffer_count; i++ )
		{
			ZeroMemory(&wh[i], sizeof(WAVEHDR));
			wh[i].dwBufferLength = block*bits/8;
			wh[i].dwFlags = 0;
			wh[i].dwLoops = 0;

			buffers[i] = new byte [block*bits/8];
			wh[i].lpData = (LPSTR)buffers[i];
		}
		
		SetEvent(evt);
		return true;
	}
	void put_data(byte* buf, int size)
	{
		unprepare();
		memcpy(get_buffer(), buf, size);
		play();
	}
};

#endif	// _MM_AUDIO_H