DM642学习点滴三：将DSP内存中的图像数据保存为BMP图像

好久没做DM642的基本实验了，今天做了一下实验19——生成图像文件的实验，仔细看了下程序代码，觉得对以后的工作可能还有借鉴意义，就做些笔记吧。

实验基本步骤呢，比较简单。将program load至DSP后运行，再用GEL文件控制命令冻结当前图像帧，程序将YCbCr格式转换成RGB格式，再将RGB数据写入新创建的BMP图像中。由于要通过仿真器将数据传至PC机，而我的仿真器是比较一般的510，速度比较慢。大概整个过程需要2分钟左右。下面附上部分程序代码：

void ICETEKDM642PCIYUVRGB()
{
	int i,j;
	int r,g,b,y,u,v;
	unsigned char *py,*pu,*pv,*pr,*pg,*pb;
	
	py=m_dbFrameY; pu=m_dbFrameU; pv=m_dbFrameV;
	pr=m_dbTargetImageR; pg=m_dbTargetImageG; pb=m_dbTargetImageB;
	for ( i=0;i<SIMGHEIGHT;i++ )   
	{  
		for ( j=0;j<SIMGWIDTH;j+=2 )   //列720点，360个32bit，
		{
			u=(*pu); v=(*pv); y=(*py);
			u-=128; v-=128;
			r=y+1.402*u;
			g=y-0.34414*u-0.71414*v;
			b=y+1.772*v;
			if ( r>255 )	r=255;
			else if ( r<0 )	r=0;
			if ( g>255 )	g=255;
			else if ( g<0 )	g=0;
			if ( b>255 )	b=255;
			else if ( b<0 )	b=0;
			(*pr)=r; pr++;
			(*pg)=g; pg++;
			(*pb)=b; pb++;
			py++; y=(*py);
			r=y+1.402*u;
			g=y-0.34414*u-0.71414*v;
			b=y+1.772*v;
			if ( r>255 )	r=255;
			else if ( r<0 )	r=0;
			if ( g>255 )	g=255;
			else if ( g<0 )	g=0;
			if ( b>255 )	b=255;
			else if ( b<0 )	b=0;
			(*pr)=r; pr++;
			(*pg)=g; pg++;
			(*pb)=b; pb++;
			py++; pu++; pv++;
		}
    }
	SaveToBMP();
}

void SaveToBMP()
{
	FILE *fp;
	unsigned char *pRGB,*pr,*pg,*pb,*pR,*pG,*pB;
	int j,i;
	unsigned int *pk;
	
	pRGB=(unsigned char *)headerImage;
	for ( i=0;i<54;i++,pRGB++ )	(*pRGB)=0;
	pRGB=(unsigned char *)headerImage;
	(*pRGB)=0x42; pRGB++;	// BM
	(*pRGB)=0x4d; pRGB++;
	pRGB+=2;
	pk=(unsigned int *)pRGB; (*pk)=14+40+180*144*3;	// size
	pRGB+=4;
	pk=(unsigned int *)pRGB; (*pk)=0;	// reserved
	pRGB+=4;
	pk=(unsigned int *)pRGB; (*pk)=54;	// image offset
	pRGB+=4;
	pk=(unsigned int *)pRGB; (*pk)=40;	// struct size
	pRGB+=4;
	pk=(unsigned int *)pRGB; (*pk)=720;	// width
	pRGB+=4;
	pk=(unsigned int *)pRGB; (*pk)=576;	// height
	pRGB+=4;
	pk=(unsigned int *)pRGB; (*pk)=0x180001;	// Planes & BitCount
	pRGB+=4;
	pk=(unsigned int *)pRGB; (*pk)=0;	// Compression
	pRGB+=4;
	pk=(unsigned int *)pRGB; (*pk)=720*576*3;	// image size
	pRGB+=4;
	pk=(unsigned int *)pRGB; (*pk)=3780;	// x pixels/m
	pRGB+=4;
	pk=(unsigned int *)pRGB; (*pk)=3780;	// y pixels/m
	pRGB+=4;
	pk=(unsigned int *)pRGB; (*pk)=0;	// color used
	pRGB+=4;
	pk=(unsigned int *)pRGB; (*pk)=0;	// important color
	if ( fp=fopen("Video.bmp","wb+") )
	{
		printf("Create a file named Video.bmp\n");
		pRGB=headerImage;
		fwrite(pRGB,2,1,fp);
		fwrite(pRGB+4,52,1,fp);
		pR=m_dbTargetImageR+720*575;
		pG=m_dbTargetImageG+720*575;
		pB=m_dbTargetImageB+720*575;
		printf("Saving image data...\n");
		for ( j=0;j<576;j++ )
		{
			pr=pR; pg=pG; pb=pB;
			for ( i=0;i<720;i++,pr++,pg++,pb++ )
			{
				fwrite(pb,1,1,fp);
				fwrite(pg,1,1,fp);
				fwrite(pr,1,1,fp);
			}
			pR-=720;
			pG-=720;
			pB-=720;
			if ( j%57==0 )
				printf("  completed %d%%\n",j/57*10);
		}
		fclose(fp);
		printf("Finished.\n");
	}
}

这里涉及到了BMP文件格式的细节。我百度了下，看到这篇博文讲到了相关内容，可对应作参考，这里不再详述。

http://www.cnblogs.com/king-77024128/articles/2056805.html

程序最终生成的文件，可以用UEStudio去仔细分析他的数据结构。