ffmpeg中常用的rgb格式轉換爲bmp圖片格式

一個簡單的工具函數：RGB24轉BMP。經過轉換後，原本只能用專用的RGB/YUV播放器查看的像素數據，就可以直接拿圖片瀏覽器查看了。

代碼如下：

int rgb24_to_bmp(const char *rgb24path,const char *bmppath,int width,int height)
{
	//定義相應的bmp數據頭結構體
	typedef struct 
	{  
		long imageSize;
		long blank;
		long startPosition;
	}BmpHead;

	typedef struct
	{
		long  Length;
		long  width;
		long  height;
		unsigned short  colorPlane;
		unsigned short  bitColor;
		long  zipFormat;
		long  realSize;
		long  xPels;
		long  yPels;
		long  colorUse;
		long  colorImportant;
	}InfoHead;
	
	int i=0,j=0;
	BmpHead m_BMPHeader={0};
	InfoHead  m_BMPInfoHeader={0};
	char bfType[2]={'B','M'};
	int header_size=sizeof(bfType)+sizeof(BmpHead)+sizeof(InfoHead);
	unsigned char *rgb24_buffer=NULL;
	FILE *fp_rgb24=NULL,*fp_bmp=NULL;
	
	if((fp_rgb24=fopen(rgb24path,"rb"))==NULL){
		printf("Error: Cannot open input RGB24 file.\n");
		return -1;
	}
	if((fp_bmp=fopen(bmppath,"wb"))==NULL){
		printf("Error: Cannot open output BMP file.\n");
		return -1;
	}
	
	rgb24_buffer=(unsigned char *)malloc(width*height*3);
	fread(rgb24_buffer,1,width*height*3,fp_rgb24);

	//設置相應的bmp頭數據結構
	m_BMPHeader.imageSize=3*width*height+header_size;
	m_BMPHeader.startPosition=header_size;

	m_BMPInfoHeader.Length=sizeof(InfoHead); 
	m_BMPInfoHeader.width=width;
	//BMP storage pixel data in opposite direction of Y-axis (from bottom to top).
	m_BMPInfoHeader.height=-height;
	m_BMPInfoHeader.colorPlane=1;
	m_BMPInfoHeader.bitColor=24;
	m_BMPInfoHeader.realSize=3*width*height;

	fwrite(bfType,1,sizeof(bfType),fp_bmp);
	fwrite(&m_BMPHeader,1,sizeof(m_BMPHeader),fp_bmp);
	fwrite(&m_BMPInfoHeader,1,sizeof(m_BMPInfoHeader),fp_bmp);

	//BMP save R1|G1|B1,R2|G2|B2 as B1|G1|R1,B2|G2|R2
	//It saves pixel data in Little Endian
	//So we change 'R' and 'B'
	for(j =0;j<height;j++){
		for(i=0;i<width;i++){
			char temp=rgb24_buffer[(j*width+i)*3+2];
			rgb24_buffer[(j*width+i)*3+2]=rgb24_buffer[(j*width+i)*3+0];
			rgb24_buffer[(j*width+i)*3+0]=temp;
		}
	}
	//寫入相應的bmp數據值部分
	fwrite(rgb24_buffer,3*width*height,1,fp_bmp);
	fclose(fp_rgb24);
	fclose(fp_bmp);
	free(rgb24_buffer);
	printf("Finish generate %s!\n",bmppath);
	return 0;
}

函數調用如下：

int main(int argc, char* argv[])
{
	//All picture's resolution is 1280x720
	//Gray Bar, from 16 to 235
	rgb24_to_bmp("colorbar_1280x720_rgb24.rgb","colorbar_1280x720_rgb24.bmp",1280,720);
	return 0;
}

生成圖片如下：