filter.cpp

截取wave通过g.729在网上压缩传输

#include "stdafx.h"
#include "Filter.h"
#include  <math.h>

CFilter::CFilter()
{
	m_hWnd = NULL;
	wBitsPerSample = 0;
}

CFilter::~CFilter()
{
	m_MDC.DeleteDC();
}

void CFilter::Init(HWND hWnd,unsigned short wBits)
{
	m_hWnd = hWnd;
	wBitsPerSample = wBits;
	m_MDC.CreateCompatibleDC (NULL);
	brush.CreateSolidBrush(RGB(0,0,0));
	pen.CreatePen (PS_SOLID,0,RGB(0,255,0));
	GetClientRect(hWnd,&memrec);
}

int CFilter::Filter(char* pBuf)
{
	if( m_hWnd == NULL || wBitsPerSample == 0 )
		return -1;

	BOOL bTalk = FALSE;
	int x,y;
	CBitmap m_bitmap;
	CBitmap *m_pOldBitmap;
	m_bitmap.CreateCompatibleBitmap(CDC::FromHandle (GetDC(m_hWnd)),memrec.Width (),memrec.Height ());
	m_pOldBitmap =(CBitmap*)SelectObject(m_MDC.GetSafeHdc (),m_bitmap);
	m_MDC.Rectangle (0,0,memrec.Width (),memrec.Height ());
	
	oldpen = m_MDC.SelectObject (&pen);
	m_MDC.FillRect(memrec,&brush);
	
	DWORD size;
	size = wBitsPerSample == 16 ? SIZE_AUDIO_FRAME/2 : SIZE_AUDIO_FRAME;
	
	int yy = memrec.Height()/2;
	m_MDC.MoveTo (0,yy);
	int h=yy;

	short sample;
	for(int register i = 0 ; i <(long)size ; i++)	//to draw first channel
	{
		sample = wBitsPerSample == 16 ? ((*((short*)pBuf+i))*h)/(65535/2) : ( (*((BYTE*)pBuf+i)-128)*h)/128;
		x = int(((float)i/size)*(memrec.Width()));
		y = yy-sample;
		if( abs(sample) > 15 && !bTalk )
		{
			bTalk = TRUE;
		}
		m_MDC.LineTo (x,y);
	}

	m_MDC.SelectObject(oldpen);

	CRect rc;
	GetClientRect(m_hWnd,&rc);
	StretchBlt(GetDC(m_hWnd),0,0,rc.Width (),rc.Height (),m_MDC.GetSafeHdc(),0,0,memrec.Width ()
		,memrec.Height(),SRCCOPY);

	if( bTalk )
		return 1;
	return 0;
}