YV12转RGB24的计算转换和bmp（dib）文件的显示保存

最近又接触到图像处理这一块，翻查到一年前自己写的代码http://blog.csdn.net/gongluck93/article/details/52813042，发现有点看不懂了！

所以自己又整理了一波（YV12转RGB24，显示和保存dib）：

#include "stdafx.h"
/*******************************************************************
* Copyright(c) 2017
* All rights reserved.
*
* 文件名称: Bmp.cpp
* 简要描述: bmp位图相关处理
*
* 创建日期: 2017-08-04
* 作者: gongluck
* 说明:
*
* 修改日期:
* 作者:
* 说明:
******************************************************************/
#include "Bmp.h"

//根据文件头和dib数据保存bmp文件
bool SaveBmpWithFileInfo(const char* filename,const BITMAPFILEHEADER* fileheader,const BITMAPINFO* bmpinfo,const void* bits)
{
FILE* fp = NULL;
if(filename == NULL || fileheader == NULL || bmpinfo == NULL || bits == NULL)
return false;
if((fp = fopen(filename,"wb")) == NULL)
return false;
fwrite(fileheader,sizeof(BITMAPFILEHEADER),1,fp);
fwrite(bmpinfo,sizeof(BITMAPINFO),1,fp);
fwrite(bits,bmpinfo->bmiHeader.biSizeImage,1,fp);
fclose(fp);
return true;
}

//根据位深度、像素宽、像素高和dib数据保存bmp文件
//深度24以下的不能处理（没有考虑有调色板的情况）
bool SaveBmpWithBitscountAndWH(const char* filename,int nBits,int width,int height,const void* bits)
{
BITMAPFILEHEADER header = {0};
BITMAPINFO info = {0};

info.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
info.bmiHeader.biWidth = width;
info.bmiHeader.biHeight = -height;
info.bmiHeader.biPlanes = 1;
info.bmiHeader.biBitCount = nBits;
info.bmiHeader.biCompression = BI_RGB;
info.bmiHeader.biSizeImage = (width * nBits + 31) / 32 * 4 * height;

header.bfSize = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFO) + info.bmiHeader.biSizeImage;
header.bfType = 0x4d42;//"BM"
header.bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFO);

return SaveBmpWithFileInfo(filename,&header,&info,bits);
}

//由位图句柄（HBITMAP）保存成bmp图片
//可以用CreateDIBitmap、CreateDIBSection等函数获取HBITMAP
bool SavePicture(HBITMAP hbitmap,const char* filepath)
{
HDC hdc= GetDC(NULL);
BITMAP bitmap = {0};
WORD clrbits = 0;
BITMAPINFO* bitmapinfo = NULL;
BITMAPFILEHEADER fileheader;
DWORD temp;
void* buf = NULL;
FILE* fp = NULL;

GetObject(hbitmap,sizeof(BITMAP),&bitmap);
clrbits = bitmap.bmBitsPixel * bitmap.bmPlanes;//每点的颜色位数*平面数
if(clrbits == 1) ;
else if(clrbits <= 4) clrbits = 4;
else if(clrbits <= 8) clrbits = 8;
else if(clrbits <= 16) clrbits = 16;
else if(clrbits <= 24) clrbits = 24;
else clrbits = 32;

if(clrbits < 24)//24位以下需要调色板
bitmapinfo = (BITMAPINFO*)malloc(sizeof(BITMAPINFOHEADER) + sizeof(RGBQUAD)*(1<<clrbits));
else
bitmapinfo = (BITMAPINFO*)malloc(sizeof(BITMAPINFOHEADER) + sizeof(RGBQUAD));

bitmapinfo->bmiHeader.biBitCount = clrbits;//图像颜色位数
bitmapinfo->bmiHeader.biClrImportant = 0;
bitmapinfo->bmiHeader.biClrUsed = (clrbits<24) ? (1<<clrbits) : 0;//使用的颜色数
bitmapinfo->bmiHeader.biCompression = BI_RGB;//压缩方式,BI_RGB不压缩
bitmapinfo->bmiHeader.biHeight = bitmap.bmHeight;//位图高度
bitmapinfo->bmiHeader.biPlanes = bitmap.bmPlanes;//设备平面数
bitmapinfo->bmiHeader.biSize = sizeof(BITMAPINFOHEADER);//BITMAPINFOHEADER结构体大小
bitmapinfo->bmiHeader.biSizeImage = (bitmap.bmWidth * clrbits + 31) / 32 * 4 * bitmap.bmHeight;//位图数据大小
bitmapinfo->bmiHeader.biWidth = bitmap.bmWidth;//位图宽度
bitmapinfo->bmiHeader.biXPelsPerMeter = bitmapinfo->bmiHeader.biYPelsPerMeter = 0;

fileheader.bfType = 0x4d42;
fileheader.bfSize = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFO)
+ sizeof(RGBQUAD)*(bitmapinfo->bmiHeader.biClrUsed==0 ? 0 : bitmapinfo->bmiHeader.biClrUsed)
+ bitmapinfo->bmiHeader.biSizeImage;
fileheader.bfReserved1 = fileheader.bfReserved2 = 0;
fileheader.bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFO) +
sizeof(RGBQUAD)*(bitmapinfo->bmiHeader.biClrUsed==0 ? 0 : bitmapinfo->bmiHeader.biClrUsed);

buf = malloc(bitmapinfo->bmiHeader.biSizeImage);
GetDIBits(hdc,hbitmap,0,bitmap.bmHeight,buf,bitmapinfo,DIB_RGB_COLORS);

fp = fopen(filepath,"wb");
fwrite(&fileheader,sizeof(BITMAPFILEHEADER),1,fp);
fwrite(bitmapinfo,sizeof(BITMAPINFO),1,fp);
fwrite(buf,bitmapinfo->bmiHeader.biSizeImage,1,fp);
fclose(fp);
free(buf);
free(bitmapinfo);
ReleaseDC(NULL,hdc);
return true;
}

//将YV12转BGR24，没有效率可言（推荐使用ffmpeg）
bool YV12ToBGR24_Native(unsigned char* pYUV,unsigned char* pBGR24,int width,int height)
{
if (width < 1 || height < 1 || pYUV == NULL || pBGR24 == NULL)
return false;
const long len = width * height;
unsigned char* yData = pYUV;
unsigned char* vData = &yData[len];
unsigned char* uData = &vData[len >> 2];

int bgr[3];
int yIdx,uIdx,vIdx,idx;
for (int i = 0;i < height;i++){
for (int j = 0;j < width;j++){
yIdx = i * width + j;
vIdx = (i/2) * (width/2) + (j/2);
uIdx = vIdx;

bgr[0] = (int)(yData[yIdx] + 1.732446 * (uData[vIdx] - 128)); // b分量
bgr[1] = (int)(yData[yIdx] - 0.698001 * (uData[uIdx] - 128) - 0.703125 * (vData[vIdx] - 128)); // g分量
bgr[2] = (int)(yData[yIdx] + 1.370705 * (vData[uIdx] - 128)); // r分量

for (int k = 0;k < 3;k++){
idx = (i * width + j) * 3 + k;
if(bgr[k] >= 0 && bgr[k] <= 255)
pBGR24[idx] = bgr[k];
else
pBGR24[idx] = (bgr[k] < 0)?0:255;
}
}
}
return true;
}github地址