bool CJpegEncoder::Encode(const BYTE* dib)
{
m_bbuff = m_bwidth = 0;
BITMAPINFO* bi = (BITMAPINFO*)dib;
int bpp = bi->bmiHeader.biBitCount;
if(bpp != 16 && bpp != 24 && bpp != 32) // 16 & 24 not tested!!! there may be some alignment problems when the row size is not 4*something in bytes
return false;
m_w = bi->bmiHeader.biWidth;
m_h = abs(bi->bmiHeader.biHeight);
m_p = new BYTE[m_w*m_h*4];
const BYTE* src = dib + sizeof(bi->bmiHeader);
if(bi->bmiHeader.biBitCount <= 8)
{
if(bi->bmiHeader.biClrUsed) src += bi->bmiHeader.biClrUsed * sizeof(bi->bmiColors[0]);
else src += (1 << bi->bmiHeader.biBitCount) * sizeof(bi->bmiColors[0]);
}
int srcpitch = m_w*(bpp>>3);
int dstpitch = m_w*4;
BitBltFromRGBToRGB(
m_w, m_h,
m_p, dstpitch, 32,
(BYTE*)src + srcpitch*(m_h-1), -srcpitch, bpp);
BYTE* p = m_p;
for(BYTE* e = p + m_h*dstpitch; p < e; p += 4)
{
int r = p[2], g = p[1], b = p[0];
p[0] = (BYTE)min(max(0.2990*r+0.5870*g+0.1140*b, 0), 255) - 128;
p[1] = (BYTE)min(max(-0.1687*r-0.3313*g+0.5000*b + 128, 0), 255) - 128;
p[2] = (BYTE)min(max(0.5000*r-0.4187*g-0.0813*b + 128, 0), 255) - 128;
}
if(quanttbl[0][0] == 16)
{
for(int i = 0; i < countof(quanttbl); i++)
for(int j = 0; j < countof(quanttbl[0]); j++)
quanttbl[i][j] >>= 2; // the default quantization table contains a little too large values
}
WriteSOI();
WriteDQT();
WriteSOF0();
WriteDHT();
WriteSOS();
WriteEOI();
delete [] m_p;
return true;
}
/////////////////////////////////////////////////////////////////////////////
// Convert YUV411 to JPEG photo file
static int YUV2Jpg(PBYTE in_Y,PBYTE in_U,PBYTE in_V,int width,int height,int quality,int nStride,PBYTE pOut,DWORD *pnOutSize)
{
PBYTE pYBuf,pUBuf,pVBuf;
int nYLen = nStride * height;
int nUVLen = nStride * height / 4;
int nDataLen;
JPEGINFO JpgInfo;
memset(&JpgInfo, 0, sizeof(JPEGINFO));
JpgInfo.bytenew = 0;
JpgInfo.bytepos = 7;
pYBuf = (PBYTE)malloc(nYLen);
memcpy(pYBuf,in_Y,nYLen);
pUBuf = (PBYTE)malloc(nYLen);
pVBuf = (PBYTE)malloc(nYLen);
ProcessUV(pUBuf,in_U,width,height,nStride);
ProcessUV(pVBuf,in_V,width,height,nStride);
// GetDataFromSource(pYBuf,pUBuf,pVBuf,in_Y,in_U,in_V,width);
DivBuff(pYBuf,width,height,nStride,DCTSIZE,DCTSIZE);
DivBuff(pUBuf,width,height,nStride,DCTSIZE,DCTSIZE);
DivBuff(pVBuf,width,height,nStride,DCTSIZE,DCTSIZE);
quality = QualityScaling(quality);
SetQuantTable(std_Y_QT,JpgInfo.YQT, quality); // 设置Y量化表
SetQuantTable(std_UV_QT,JpgInfo.UVQT,quality); // 设置UV量化表
InitQTForAANDCT(&JpgInfo); // 初始化AA&N需要的量化表
JpgInfo.pVLITAB=JpgInfo.VLI_TAB + 2048; // 设置VLI_TAB的别名
BuildVLITable(&JpgInfo); // 计算VLI表
nDataLen = 0;
// 写入各段
nDataLen = WriteSOI(pOut,nDataLen);
nDataLen = WriteAPP0(pOut,nDataLen);
nDataLen = WriteDQT(&JpgInfo,pOut,nDataLen);
nDataLen = WriteSOF(pOut,nDataLen,width,height);
nDataLen = WriteDHT(pOut,nDataLen);
nDataLen = WriteSOS(pOut,nDataLen);
// 计算Y/UV信号的交直分量的huffman表，这里使用标准的huffman表，并不是计算得出，缺点是文件略长，但是速度快
BuildSTDHuffTab(STD_DC_Y_NRCODES,STD_DC_Y_VALUES,JpgInfo.STD_DC_Y_HT);
BuildSTDHuffTab(STD_AC_Y_NRCODES,STD_AC_Y_VALUES,JpgInfo.STD_AC_Y_HT);
BuildSTDHuffTab(STD_DC_UV_NRCODES,STD_DC_UV_VALUES,JpgInfo.STD_DC_UV_HT);
BuildSTDHuffTab(STD_AC_UV_NRCODES,STD_AC_UV_VALUES,JpgInfo.STD_AC_UV_HT);
// 处理单元数据
nDataLen = ProcessData(&JpgInfo,pYBuf,pUBuf,pVBuf,width,height,pOut,nDataLen);
nDataLen = WriteEOI(pOut,nDataLen);
free(pYBuf);
free(pUBuf);
free(pVBuf);
*pnOutSize = nDataLen;
return 0;
}
