Yuv420轉Jpeg(C語言實現)
YUV2Jpg(in_Y,in_U,in_V,0x400,0x1b0,75,0x420,pData,&dwSize);
引數說明:in_Y:輸入的420的Y分量;in_U:輸入的420的U分量,in_V:輸入420的V分量;width:表示影象的寬;height表示影象的高;quality表示量化因子,n_Stride表示Yuv的跨度,即Yuv的寬,因為該函式只能處理16的整數倍,所以width為0x400;pOut表示轉化後的資料;pnOutSize為轉化後的jpeg檔案的大小;
int YUV2Jpg(PBYTE in_Y,PBYTE in_U,PBYTE in_V,int width,int
{
PBYTE pYBuf,pUBuf,pVBuf;
int nYLen = nStride * height;
int nUVLen = nStride * height / 4;
int nDataLen;
JPEGINFO JpgInfo;
ZeroMemory(&JpgInfo,sizeof(JPEGINFO));
JpgInfo.bytenew = 0;
JpgInfo.bytepos = 7;
pYBuf = (PBYTE)malloc(nYLen); //獲取Y的值
memcpy(pYBuf,in_Y,nYLen);
pUBuf = (PBYTE)malloc(nYLen);
pVBuf = (PBYTE)malloc(nYLen);
ProcessUV(pUBuf,in_U,width,height,nStride); //獲取U的值
ProcessUV(pVBuf,in_V,width,height,nStride); //獲取V
//
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); // 設定Y量化表
SetQuantTable(std_UV_QT,JpgInfo.UVQT,quality); // 設定UV量化表
InitQTForAANDCT(&JpgInfo); // 初始化AA&N需要的量化表
JpgInfo.pVLITAB=JpgInfo.VLI_TAB + 2048; // 設定VLI_TAB的別名
BuildVLITable(&JpgInfo); // 計算VLI表
nDataLen = 0;
// 寫入各段
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);
// 計算Y/UV訊號的交直分量的huffman表,這裡使用標準的huffman表,並不是計算得出,缺點是檔案略長,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);
// 處理單元資料
nDataLen = ProcessData(&JpgInfo,pYBuf,pUBuf,pVBuf,width,height,pOut,nDataLen);
nDataLen = WriteEOI(pOut,nDataLen);
free(pYBuf);
free(pUBuf);
free(pVBuf);
*pnOutSize = nDataLen;
return 0;
}
具體程式碼參考YUV2Jpg程式;