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发表于 2012-3-19 12:40:15
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给你豪华版的jpeg解码代码参考一下:
#include "piclib.h"
#include "jpeg.h"
//反Z字形编码表
const int Zig_Zag[8][8]=
{
{0,1,5,6,14,15,27,28},
{2,4,7,13,16,26,29,42},
{3,8,12,17,25,30,41,43},
{9,11,18,24,31,40,44,53},
{10,19,23,32,39,45,52,54},
{20,22,33,38,46,51,55,60},
{21,34,37,47,50,56,59,61},
{35,36,48,49,57,58,62,63}
};
const u8 And[9]={0,1,3,7,0xf,0x1f,0x3f,0x7f,0xff};
/////////////////////////////////////// ///////////////////////////////////////////////////////////
//在JPEG函数里面用到的变量
short SampRate_Y_H,SampRate_Y_V;
short SampRate_U_H,SampRate_U_V;
short SampRate_V_H,SampRate_V_V;
short H_YtoU,V_YtoU,H_YtoV,V_YtoV;
short Y_in_MCU,U_in_MCU,V_in_MCU;
short BitPos,Curu8; //u8的第几位,当前u8
short rrun,vvalue;
short comp_num;
short restart;
short ycoef,ucoef,vcoef;
short *YQtTable,*UQtTable,*VQtTable;
short interval=0;
u32 sizei,sizej;
u8 comp_index[3];
u8 YDcIndex,YAcIndex,UVDcIndex,UVAcIndex;
u8 HufTabIndex;
u8 *lp; //取代lpJpegBuf
u8 IntervalFlag;
long *iclp;
/////////////////////////////////////// ///////////////////////////////////////////////////////////
//下面根据是否使用malloc来决定变量的分配方法.
#if JPEG_USE_MALLOC == 1 //使用malloc
FIL *f_jpeg;
short *qt_table[3];
short *code_pos_table[4],*code_len_table[4];
u16 *huf_max_value[4],*huf_min_value[4];
short *MCUBuffer;
short *QtZzMCUBuffer;
short *BlockBuffer;
short *Y,*U,*V;
u16 *code_value_table[4];
long *iclip; //4k字节缓存
u8 *jpg_buffer; //数据缓存区
#else //不使用malloc
FIL f_jtemp;
FIL *f_jpeg=&f_jtemp;
short qt_table[3][64];
short code_pos_table[4][16],code_len_table[4][16];
u16 huf_max_value[4][16],huf_min_value[4][16];
short MCUBuffer[10*64];
short QtZzMCUBuffer[10*64];
short BlockBuffer[64];
short Y[4*64],U[4*64],V[4*64];
u16 code_value_table[4][256];
long iclip[1024]; //4k字节缓存
u8 jpg_buffer[1024]; //数据缓存区
#endif
/////////////////////////////////////////////////////////////////////////////////////////
#if JPEG_USE_MALLOC == 1 //使用malloc
//给占内存大的数组申请内存
u8 jpeg_mallocall(void)
{
u8 i;
f_jpeg=(FIL*)mymalloc(SRAMIN,sizeof(FIL));
if(f_jpeg==NULL)return  IC_MEM_ERR; //申请内存失败.
iclip=(long*)mymalloc(SRAMIN,1024*4);
if(iclip==NULL)return  IC_MEM_ERR; //申请内存失败.
jpg_buffer=(u8*)mymalloc(SRAMIN,1024);
if(jpg_buffer==NULL)return  IC_MEM_ERR; //申请内存失败.
for(i=0;i<4;i++)
{
if(i<3)
{
qt_table=(short*)mymalloc(SRAMIN,128);
if(qt_table==NULL)return  IC_MEM_ERR;//申请内存失败.
}
code_pos_table=(short*)mymalloc(SRAMIN,32);
if(code_pos_table==NULL)return  IC_MEM_ERR;//申请内存失败.
code_len_table=(short*)mymalloc(SRAMIN,32);
if(code_len_table==NULL)return  IC_MEM_ERR;//申请内存失败.
huf_max_value=(u16*)mymalloc(SRAMIN,32);
if(huf_max_value==NULL)return  IC_MEM_ERR;//申请内存失败.
huf_min_value=(u16*)mymalloc(SRAMIN,32);
if(huf_min_value==NULL)return  IC_MEM_ERR;//申请内存失败.
code_value_table=(u16*)mymalloc(SRAMIN,1024);
if(code_value_table==NULL)return  IC_MEM_ERR;//申请内存失败.
}
MCUBuffer=(short*)mymalloc(SRAMIN,1280);
if(MCUBuffer==NULL)return  IC_MEM_ERR;//申请内存失败.
QtZzMCUBuffer=(short*)mymalloc(SRAMIN,1280);
if(QtZzMCUBuffer==NULL)return PIC_MEM_ERR;//申请内存失败.
BlockBuffer=(short*)mymalloc(SRAMIN,128);
if(BlockBuffer==NULL)return PIC_MEM_ERR;//申请内存失败.
Y=(short*)mymalloc(SRAMIN,512);
if(Y==NULL)return PIC_MEM_ERR;//申请内存失败.
U=(short*)mymalloc(SRAMIN,512);
if(U==NULL)return PIC_MEM_ERR;//申请内存失败.
V=(short*)mymalloc(SRAMIN,512);
if(V==NULL)return PIC_MEM_ERR;//申请内存失败.
return 0;
}
//释放内存
void jpeg_freeall(void)
{
u8 i;
myfree(SRAMIN,f_jpeg); //释放f_jpeg申请到的内存
myfree(SRAMIN,iclip); //释放iclip申请到的内存
myfree(SRAMIN,jpg_buffer); //释放jpg_buffer申请到的内存
for(i=0;i<4;i++)
{
if(i<3)myfree(SRAMIN,qt_table); //释放内存
myfree(SRAMIN,code_pos_table); //释放内存
myfree(SRAMIN,code_len_table); //释放内存
myfree(SRAMIN,huf_max_value); //释放内存
myfree(SRAMIN,huf_min_value); //释放内存
myfree(SRAMIN,code_value_table); //释放内存
}
myfree(SRAMIN,MCUBuffer); //释放内存
myfree(SRAMIN,QtZzMCUBuffer); //释放内存
myfree(SRAMIN,BlockBuffer); //释放内存
myfree(SRAMIN,Y); //释放内存
myfree(SRAMIN,U); //释放内存
myfree(SRAMIN,V); //释放内存
}
#endif
//解码文件名为filename的jpeg/jpg文件
u8 jpg_decode(const u8 *filename)
{
u8 res=0;
u16 br;
#if JPEG_USE_MALLOC == 1//使用malloc
res=jpeg_mallocall();
#endif
if(res==0)//内存申请OK
{
//得到JPEG/JPG图片的开始信息
res=f_open(f_jpeg,(const TCHAR*)filename,FA_READ);//打开文件
if(res==0)
{
//开始时读入1024个字节到缓存里面.方便后面提取JPEG解码的信息
f_read(f_jpeg,jpg_buffer,1024,(UINT*)&br);
jpeg_inittable();//初始化各个数据表
res=jpeg_inittag();
if(res==0)
{
if((SampRate_Y_H!=0)&&(SampRate_Y_V!=0))
{
ai_drow_init(); //初始化picinfo.Div_Fac,启动智能画图
res=jpeg_decode(); //解码JPEG开始
}else res=0XFD; //采样率错误
}else res=0XFE; //初始化表头不成功
}
f_close(f_jpeg);
}
#if JPEG_USE_MALLOC == 1//使用malloc
jpeg_freeall(); //释放内存
#endif
return res;
}
//文件指针移动.
//*pbase:数据存储区首地址.
//**pnow:指向当前字节指针.
void jpg_seek(u8*pbase,u8**pnow)
{
u32 pos;
u16 offset;
offset=*pnow-pbase;//当前的偏移量.
if(offset>1000)//将要结束了,做下一次读取
{
pos=f_tell(f_jpeg); //得到当前位置
f_lseek(f_jpeg,pos-1024+offset);//偏移
f_read(f_jpeg,pbase,1024,&br); //读取1024个字节.
*pnow=pbase;//复位
}
}
//初始化d_buffer的数据
int jpeg_inittag(void)
{
u8 finish=FALSE;
u8 id;
short llength;
short i,j,k;
short huftab1,huftab2;
short huftabindex;
u8 hf_table_index;
u8 qt_table_index;
u8 comnum;//最长为256个字节
u8 *lptemp;
short colorount;
lp=jpg_buffer+2;//跳过两个字节SOI(0xFF,0xD8 Start of Image)
jpg_seek(jpg_buffer,&lp);
while (!finish)
{
id=*(lp+1);//取出低位字节(高位在前,低位在后)
lp+=2; //跳过取出的字节
jpg_seek(jpg_buffer,&lp);
switch (id)
{
case M_APP0: //JFIF APP0 segment marker (0xE0)
//标志应用数据段的开始
llength=MAKEWORD(*(lp+1),*lp);//得到应用数据段长度
lp+=llength;
jpg_seek(jpg_buffer,&lp);
break;
case M_DQT: //定义量化表标记(0xFF,0xDB)
llength=MAKEWORD(*(lp+1),*lp);//(量化表长度)两个字节
qt_table_index=(*(lp+2))&0x0f;//量化表信息bit 0..3: QT 号(0..3, 否则错误)
//bit 4..7: QT 精度, 0 = 8 bit, 否则 16 bit
lptemp=lp+3; //n 字节的 QT, n = 64*(精度+1)
//d_buffer里面至少有有512个字节的余度,这里最大用到128个字节
if(llength<80) //精度为 8 bit
{
for(i=0;i<64;i++)qt_table[qt_table_index]=(short)*(lptemp++);
}
else //精度为 16 bit
{
for(i=0;i<64;i++)qt_table[qt_table_index]=(short)*(lptemp++);
qt_table_index=(*(lptemp++))&0x0f;
for(i=0;i<64;i++)qt_table[qt_table_index]=(short)*(lptemp++);
}
lp+=llength; //跳过量化表
jpg_seek(jpg_buffer,&lp);
break;
case M_SOF0: //帧开始 (baseline JPEG 0xFF,0xC0)
llength=MAKEWORD(*(lp+1),*lp); //长度 (高字节, 低字节), 8+components*3
picinfo.ImgHeight=MAKEWORD(*(lp+4),*(lp+3));//图片高度 (高字节, 低字节), 如果不支持 DNL 就必须 >0
picinfo.ImgWidth=MAKEWORD(*(lp+6),*(lp+5)); //图片宽度 (高字节, 低字节), 如果不支持 DNL 就必须 >0
comp_num=*(lp+7);//components 数量(1 u8), 灰度图是 1, YCbCr/YIQ 彩色图是 3, CMYK 彩色图是 4
if((comp_num!=1)&&(comp_num!=3))return FUNC_FORMAT_ERROR;// 格式错误
if(comp_num==3) //YCbCr/YIQ 彩色图
{
comp_index[0]=*(lp+8); //component id (1 = Y, 2 = Cb, 3 = Cr, 4 = I, 5 = Q)
SampRate_Y_H=(*(lp+9))>>4; //水平采样系数
SampRate_Y_V=(*(lp+9))&0x0f;//垂直采样系数
YQtTable=(short *)qt_table[*(lp+10)];//通过量化表号取得量化表地址
comp_index[1]=*(lp+11); //component id
SampRate_U_H=(*(lp+12))>>4; //水平采样系数
SampRate_U_V=(*(lp+12))&0x0f; //垂直采样系数
UQtTable=(short *)qt_table[*(lp+13)];//通过量化表号取得量化表地址
comp_index[2]=*(lp+14); //component id
SampRate_V_H=(*(lp+15))>>4; //水平采样系数
SampRate_V_V=(*(lp+15))&0x0f; //垂直采样系数
VQtTable=(short *)qt_table[*(lp+16)];//通过量化表号取得量化表地址
}
else //component id
{
comp_index[0]=*(lp+8);
SampRate_Y_H=(*(lp+9))>>4;
SampRate_Y_V=(*(lp+9))&0x0f;
YQtTable=(short *)qt_table[*(lp+10)];//灰度图的量化表都一样
comp_index[1]=*(lp+8);
SampRate_U_H=1;
SampRate_U_V=1;
UQtTable=(short *)qt_table[*(lp+10)];
comp_index[2]=*(lp+8);
SampRate_V_H=1;
SampRate_V_V=1;
VQtTable=(short *)qt_table[*(lp+10)];
}
lp+=llength;
jpg_seek(jpg_buffer,&lp);
break;
case M_DHT: //定义哈夫曼表(0xFF,0xC4)
llength=MAKEWORD(*(lp+1),*lp);//长度 (高字节, 低字节)
if (llength<0xd0) // Huffman Table信息 (1 u8)
{
huftab1=(short)(*(lp+2))>>4; //huftab1=0,1(HT 类型,0 = DC 1 = AC)
huftab2=(short)(*(lp+2))&0x0f; //huftab2=0,1(HT 号 ,0 = Y 1 = UV)
huftabindex=huftab1*2+huftab2; //0 = YDC 1 = UVDC 2 = YAC 3 = UVAC
lptemp=lp+3;//!!!
//在这里可能出现余度不够,多于512字节,则会导致出错!!!!
for (i=0; i<16; i++) //16 u8s: 长度是 1..16 代码的符号数
code_len_table[huftabindex]=(short)(*(lptemp++));//码长为i的码字个数
j=0;
for (i=0; i<16; i++) //得出HT的所有码字的对应值
{
if(code_len_table[huftabindex]!=0)
{
k=0;
while(k<code_len_table[huftabindex])
{
code_value_table[huftabindex][k+j]=(short)(*(lptemp++));//最可能的出错地方
k++;
}
j+=k;
}
}
i=0;
while (code_len_table[huftabindex]==0)i++;
for (j=0;j<i;j++)
{
huf_min_value[huftabindex][j]=0;
huf_max_value[huftabindex][j]=0;
}
huf_min_value[huftabindex]=0;
huf_max_value[huftabindex]=code_len_table[huftabindex]-1;
for (j=i+1;j<16;j++)
{
huf_min_value[huftabindex][j]=(huf_max_value[huftabindex][j-1]+1)<<1;
huf_max_value[huftabindex][j]=huf_min_value[huftabindex][j]+code_len_table[huftabindex][j]-1;
}
code_pos_table[huftabindex][0]=0;
for (j=1;j<16;j++)
code_pos_table[huftabindex][j]=code_len_table[huftabindex][j-1]+code_pos_table[huftabindex][j-1];
lp+=llength;
jpg_seek(jpg_buffer,&lp);
}//if
else
{
hf_table_index=*(lp+2);
lp+=2;
jpg_seek(jpg_buffer,&lp);
while (hf_table_index!=0xff)
{
huftab1=(short)hf_table_index>>4; //huftab1=0,1
huftab2=(short)hf_table_index&0x0f; //huftab2=0,1
huftabindex=huftab1*2+huftab2;
lptemp=lp+1;
colorount=0;
for (i=0; i<16; i++)
{
code_len_table[huftabindex]=(short)(*(lptemp++));
colorount+=code_len_table[huftabindex];
}
colorount+=17;
j=0;
for (i=0; i<16; i++)
{
if(code_len_table[huftabindex]!=0)
{
k=0;
while(k<code_len_table[huftabindex])
{
code_value_table[huftabindex][k+j]=(short)(*(lptemp++));//最可能出错的地方,余度不够
k++;
}
j+=k;
}
}
i=0;
while (code_len_table[huftabindex]==0)i++;
for (j=0;j<i;j++)
{
huf_min_value[huftabindex][j]=0;
huf_max_value[huftabindex][j]=0;
}
huf_min_value[huftabindex]=0;
huf_max_value[huftabindex]=code_len_table[huftabindex]-1;
for (j=i+1;j<16;j++)
{
huf_min_value[huftabindex][j]=(huf_max_value[huftabindex][j-1]+1)<<1;
huf_max_value[huftabindex][j]=huf_min_value[huftabindex][j]+code_len_table[huftabindex][j]-1;
}
code_pos_table[huftabindex][0]=0;
for (j=1;j<16;j++)
code_pos_table[huftabindex][j]=code_len_table[huftabindex][j-1]+code_pos_table[huftabindex][j-1];
lp+=colorount;
jpg_seek(jpg_buffer,&lp);
hf_table_index=*lp;
} //while
} //else
break;
case M_DRI://定义差分编码累计复位的间隔
llength=MAKEWORD(*(lp+1),*lp);
restart=MAKEWORD(*(lp+3),*(lp+2));
lp+=llength;
jpg_seek(jpg_buffer,&lp);
break;
case M_SOS: //扫描开始 12字节
llength=MAKEWORD(*(lp+1),*lp);
comnum=*(lp+2);
if(comnum!=comp_num)return FUNC_FORMAT_ERROR; //格式错误
lptemp=lp+3;//这里也可能出现错误
//这里也可能出错,但是几率比较小了
for (i=0;i<comp_num;i++)//每组件的信息
{
if(*lptemp==comp_index[0])
{
YDcIndex=(*(lptemp+1))>>4; //Y 使用的 Huffman 表
YAcIndex=((*(lptemp+1))&0x0f)+2;
}
else
{
UVDcIndex=(*(lptemp+1))>>4; //U,V
UVAcIndex=((*(lptemp+1))&0x0f)+2;
}
lptemp+=2;//comp_num<256,但是2*comp_num+3可能>=512
}
lp+=llength;
jpg_seek(jpg_buffer,&lp);
finish=TRUE;
break;
case M_EOI:return FUNC_FORMAT_ERROR;//图片结束 标记
default:
if ((id&0xf0)!=0xd0)
{
llength=MAKEWORD(*(lp+1),*lp);
lp+=llength;
jpg_seek(jpg_buffer,&lp);
}
else lp+=2;
break;
} //switch
} //while
return FUNC_OK;
}
//初始化量化表,全部清零
void jpeg_inittable(void)
{
short i,j;
sizei=sizej=0;
picinfo.ImgWidth=picinfo.ImgHeight=0;
rrun=vvalue=0;
BitPos=0;
Curu8=0;
IntervalFlag=FALSE;
restart=0;
for(i=0;i<3;i++) //量化表
for(j=0;j<64;j++)
qt_table[j]=0;
comp_num=0;
HufTabIndex=0;
for(i=0;i<3;i++)
comp_index=0;
for(i=0;i<4;i++)
for(j=0;j<16;j++){
code_len_table[j]=0;
code_pos_table[j]=0;
huf_max_value[j]=0;
huf_min_value[j]=0;
}
for(i=0;i<4;i++)
for(j=0;j<256;j++)
code_value_table[j]=0;
for(i=0;i<10*64;i++){
MCUBuffer=0;
QtZzMCUBuffer=0;
}
for(i=0;i<64;i++){
Y=0;
U=0;
V=0;
BlockBuffer=0;
}
ycoef=ucoef=vcoef=0;
}
//调用顺序: jpeg_initfastidct():初始化
// jpeg_decodemcublock() Huffman Decode
// jpeg_iqtizzmcucomponent() 反量化、反DCT
// jpeg_getyuv() Get Y U V
// jpeg_storebuffer() YUV to RGB
int jpeg_decode(void)
{
int funcret;
Y_in_MCU=SampRate_Y_H*SampRate_Y_V;//YDU YDU YDU YDU
U_in_MCU=SampRate_U_H*SampRate_U_V;//cRDU
V_in_MCU=SampRate_V_H*SampRate_V_V;//cBDU
H_YtoU=SampRate_Y_H/SampRate_U_H;
V_YtoU=SampRate_Y_V/SampRate_U_V;
H_YtoV=SampRate_Y_H/SampRate_V_H;
V_YtoV=SampRate_Y_V/SampRate_V_V;
jpeg_initfastidct();
while((funcret=jpeg_decodemcublock())==FUNC_OK) //After Call DecodeMCUBUBlock()
{
interval++; //The Digital has been Huffman Decoded and
if((restart)&&(interval % restart==0))//be stored in MCUBuffer(YDU,YDU,YDU,YDU
IntervalFlag=TRUE; // UDU,VDU) Every DU:= 8*8
else
IntervalFlag=FALSE;
jpeg_iqtizzmcucomponent(0); //反量化 and IDCT The Data in QtZzMCUBuffer
jpeg_iqtizzmcucomponent(1);
jpeg_iqtizzmcucomponent(2);
jpeg_getyuv(0); //得到Y cR cB
jpeg_getyuv(1);
jpeg_getyuv(2);
jpeg_storebuffer(); //To RGB
sizej+=SampRate_Y_H*8;
if(sizej>=picinfo.ImgWidth)
{
sizej=0;
sizei+=SampRate_Y_V*8;
}
if ((sizej==0)&&(sizei>=picinfo.ImgHeight))break;
}
return funcret;
}
// 入口 QtZzMCUBuffer 出口 Y[] U[] V[]
//得到YUV色彩空间
void jpeg_getyuv(short flag)
{
short H=0,VV=0;
short i,j,k,h;
short *buf=0;
short *pQtZzMCU=0;
switch(flag)
{
case 0://亮度分量
H=SampRate_Y_H;
VV=SampRate_Y_V;
buf=Y;
pQtZzMCU=QtZzMCUBuffer;
break;
case 1://红色分量
H=SampRate_U_H;
VV=SampRate_U_V;
buf=U;
pQtZzMCU=QtZzMCUBuffer+Y_in_MCU*64;
break;
case 2://蓝色分量
H=SampRate_V_H;
VV=SampRate_V_V;
buf=V;
pQtZzMCU=QtZzMCUBuffer+(Y_in_MCU+U_in_MCU)*64;
break;
}
for (i=0;i<VV;i++)
for(j=0;j<H;j++)
for(k=0;k<8;k++)
for(h=0;h<8;h++)
buf[(i*8+k)*SampRate_Y_H*8+j*8+h]=*pQtZzMCU++;
}
//将解出的字按RGB形式存储 lpbmp (BGR),(BGR) ......入口Y[] U[] V[] 出口lpPtr
void jpeg_storebuffer(void)
{
short i=0,j=0;
u8 R,G,B;
int y,u,v,rr,gg,bb;
u16 color;
//x,y的实际坐标
u16 realx=sizej;
u16 realy=0;
for(i=0;i<SampRate_Y_V*8;i++)
{
if((sizei+i)><picinfo.ImgHeight)// sizei表示行 sizej 表示列
{
realy=picinfo.Div_Fac*(sizei+i)/10000;//实际Y坐标
//在这里不改变picinfo.staticx和picinfo.staticy的值 ,如果在这里改变,则会造成每块的第一个点不显示!!!
if(!is_element_ok(realx,realy,0))continue;//列值是否满足条件? 寻找满足条件的列
for(j=0;j<SampRate_Y_H*8;j++)
{
if((sizej+j)><picinfo.ImgWidth)
{
realx=picinfo.Div_Fac*(sizej+j)/10000;//实际X坐标
//在这里改变picinfo.staticx和picinfo.staticy的值
if(!is_element_ok(realx,realy,1))continue;//列值是否满足条件? 寻找满足条件的行
y=Y[i*8*SampRate_Y_H+j];
u=U[(i/V_YtoU)*8*SampRate_Y_H+j/H_YtoU];
v=V[(i/V_YtoV)*8*SampRate_Y_H+j/H_YtoV];
rr=((y<<8)+18*u+367*v)>>8;
gg=((y<<8)-159*u-220*v)>>8;
bb=((y<<8)+411*u-29*v)>>8;
R=(u8)rr;
G=(u8)gg;
B=(u8)bb;
if (rr&0xffffff00) if (rr>255) R=255; else if (rr<0) R=0;
if (gg&0xffffff00) if (gg>255) G=255; else if (gg<0) G=0;
if (bb&0xffffff00) if (bb>255) B=255; else if (bb<0) B=0;
color=R>>3;
color=color<<6;
color |=(G>>2);
color=color<<5;
color |=(B>>3);
//在这里送给LCD显示
gui_phy.draw_point(realx+picinfo.S_XOFF,realy+picinfo.S_YOFF,color);//显示图片
//POINT_COLOR=color;
//LCD_DrawPoint(realx+picinfo.S_XOFF,realy+picinfo.S_YOFF);//显示图片
}
else break;
}
}
else break;
}
}
//Huffman Decode MCU 出口 MCUBuffer 入口Blockbuffer[ ]
int jpeg_decodemcublock(void)
{
short *lpMCUBuffer;
short i,j;
int funcret;
if (IntervalFlag)//差值复位
{
lp+=2;
jpg_seek(jpg_buffer,&lp);
ycoef=ucoef=vcoef=0;
BitPos=0;
Curu8=0;
}
switch(comp_num)
{
case 3: //comp_num 指图的类型(彩色图、灰度图)
lpMCUBuffer=MCUBuffer;
for (i=0;i<SampRate_Y_H*SampRate_Y_V;i++) //Y
{
funcret=jpeg_hufblock(YDcIndex,YAcIndex);//解码4 * (8*8)
if (funcret!=FUNC_OK)
return funcret;
BlockBuffer[0]=BlockBuffer[0]+ycoef;//直流分量是差值,所以要累加。
ycoef=BlockBuffer[0];
for (j=0;j<64;j++)
*lpMCUBuffer++=BlockBuffer[j];
}
for (i=0;i<SampRate_U_H*SampRate_U_V;i++) //U
{
funcret=jpeg_hufblock(UVDcIndex,UVAcIndex);
if (funcret!=FUNC_OK)
return funcret;
BlockBuffer[0]=BlockBuffer[0]+ucoef;
ucoef=BlockBuffer[0];
for (j=0;j<64;j++)
*lpMCUBuffer++=BlockBuffer[j];
}
for (i=0;i<SampRate_V_H*SampRate_V_V;i++) //V
{
funcret=jpeg_hufblock(UVDcIndex,UVAcIndex);
if (funcret!=FUNC_OK)
return funcret;
BlockBuffer[0]=BlockBuffer[0]+vcoef;
vcoef=BlockBuffer[0];
for (j=0;j<64;j++)
*lpMCUBuffer++=BlockBuffer[j];
}
break;
case 1: //Gray Picture
lpMCUBuffer=MCUBuffer;
funcret=jpeg_hufblock(YDcIndex,YAcIndex);
if (funcret!=FUNC_OK)
return funcret;
BlockBuffer[0]=BlockBuffer[0]+ycoef;
ycoef=BlockBuffer[0];
for (j=0;j<64;j++)
*lpMCUBuffer++=BlockBuffer[j];
for (i=0;i<128;i++)
*lpMCUBuffer++=0;
break;
default:
return FUNC_FORMAT_ERROR;
}
return FUNC_OK;
}
//Huffman Decode (8*8) DU 出口 Blockbuffer[ ] 入口 vvalue
int jpeg_hufblock(u8 dchufindex,u8 achufindex)
{
short count=0;
short i;
int funcret;
//dc
HufTabIndex=dchufindex;
funcret=jpeg_decodeelement();
if(funcret!=FUNC_OK)return funcret;
BlockBuffer[count++]=vvalue;//解出的直流系数
//ac
HufTabIndex=achufindex;
while (count><64)
{
funcret=jpeg_decodeelement();
if(funcret!=FUNC_OK)
return funcret;
if ((rrun==0)&&(vvalue==0))
{
for (i=count;i<64;i++)BlockBuffer=0;
count=64;
}
else
{
for (i=0;i<rrun;i++)BlockBuffer[count++]=0;//前面的零
BlockBuffer[count++]=vvalue;//解出的值
}
}
return FUNC_OK;
}
//Huffman 解码 每个元素 出口 vvalue 入口 读文件Readu8
int jpeg_decodeelement()
{
int thiscode,tempcode;
u16 temp,valueex;
short codelen;
u8 hufexu8,runsize,tempsize,sign;
u8 newu8,lastu8;
if(BitPos>=1) //BitPos指示当前比特位置
{
BitPos--;
thiscode=(u8)Curu8>>BitPos;//取一个比特
Curu8=Curu8&And[BitPos]; //清除取走的比特位
}
else //取出的一个字节已用完
{ //新取
lastu8=jpeg_readu8(); //读出一个字节
BitPos--; //and[]:=0x0,0x1,0x3,0x7,0xf,0x1f,0x2f,0x3f,0x4f
newu8=Curu8&And[BitPos];
thiscode=lastu8>>7;
Curu8=newu8;
}
codelen=1;
//与Huffman表中的码字匹配,直自找到为止
while ((thiscode<huf_min_value[HufTabIndex][codelen-1])||
(code_len_table[HufTabIndex][codelen-1]==0)||
(thiscode>huf_max_value[HufTabIndex][codelen-1]))
{
if(BitPos>=1)//取出的一个字节还有
{
BitPos--;
tempcode=(u8)Curu8>>BitPos;
Curu8=Curu8&And[BitPos];
}
else
{
lastu8=jpeg_readu8();
BitPos--;
newu8=Curu8&And[BitPos];
tempcode=(u8)lastu8>>7;
Curu8=newu8;
}
thiscode=(thiscode<<1)+tempcode;
codelen++;
if(codelen>16)return FUNC_FORMAT_ERROR;
} //while
temp=thiscode-huf_min_value[HufTabIndex][codelen-1]+code_pos_table[HufTabIndex][codelen-1];
hufexu8=(u8)code_value_table[HufTabIndex][temp];
rrun=(short)(hufexu8>>4); //一个字节中,高四位是其前面的零的个数。
runsize=hufexu8&0x0f; //后四位为后面字的尺寸
if(runsize==0)
{
vvalue=0;
return FUNC_OK;
}
tempsize=runsize;
if(BitPos>=runsize)
{
BitPos-=runsize;
valueex=(u8)Curu8>>BitPos;
Curu8=Curu8&And[BitPos];
}
else
{
valueex=Curu8;
tempsize-=BitPos;
while(tempsize>8)
{
lastu8=jpeg_readu8();
valueex=(valueex<<8)+(u8)lastu8;
tempsize-=8;
} //while
lastu8=jpeg_readu8();
BitPos-=tempsize;
valueex=(valueex<<tempsize)+(lastu8>>BitPos);
Curu8=lastu8&And[BitPos];
} //else
sign=valueex>>(runsize-1);
if(sign)vvalue=valueex;//解出的码值
else
{
valueex=valueex^0xffff;
temp=0xffff<<runsize;
vvalue=-(short)(valueex^temp);
}
return FUNC_OK;
}
//反量化MCU中的每个组件 入口 MCUBuffer 出口 QtZzMCUBuffer
void jpeg_iqtizzmcucomponent(short flag)
{
short H=0,VV=0;
short i,j;
short *pQtZzMCUBuffer=0;
short *pMCUBuffer=0;
switch(flag){
case 0:
H=SampRate_Y_H;
VV=SampRate_Y_V;
pMCUBuffer=MCUBuffer;
pQtZzMCUBuffer=QtZzMCUBuffer;
break;
case 1:
H=SampRate_U_H;
VV=SampRate_U_V;
pMCUBuffer=MCUBuffer+Y_in_MCU*64;
pQtZzMCUBuffer=QtZzMCUBuffer+Y_in_MCU*64;
break;
case 2:
H=SampRate_V_H;
VV=SampRate_V_V;
pMCUBuffer=MCUBuffer+(Y_in_MCU+U_in_MCU)*64;
pQtZzMCUBuffer=QtZzMCUBuffer+(Y_in_MCU+U_in_MCU)*64;
break;
}
for(i=0;i<VV;i++)
for (j=0;j<H;j++)
jpeg_iqtizzblock(pMCUBuffer+(i*H+j)*64,pQtZzMCUBuffer+(i*H+j)*64,flag);
}
//要量化的字
//反量化 8*8 DU
void jpeg_iqtizzblock(short *s ,short * d,short flag)
{
short i,j;
short tag;
short *pQt=0;
int buffer2[8][8];
int *buffer1;
short offset=0;
switch(flag)
{
case 0: //亮度
pQt=YQtTable;
offset=128;
break;
case 1: //红
pQt=UQtTable;
offset=0;
break;
case 2: //蓝
pQt=VQtTable;
offset=0;
break;
}
for(i=0;i<8;i++)
for(j=0;j<8;j++)
{
tag=Zig_Zag[j];
buffer2[j]=(int)s[tag]*(int)pQt[tag];
}
buffer1=(int *)buffer2;
jpeg_fastidct(buffer1);//反DCT
for(i=0;i<8;i++)
for(j=0;j<8;j++)
d[i*8+j]=buffer2[j]+offset;
}
//快速反DCT
void jpeg_fastidct(int * block)
{
short i;
for (i=0; i><8; i++)jpeg_idctrow(block+8*i);
for (i=0; i<8; i++)jpeg_idctcol(block+i);
}
//从源文件读取一个字节
u8 jpeg_readu8(void)
{
u8 i;
i=*lp++;
jpg_seek(jpg_buffer,&lp);
if(i==0xff)lp++;
BitPos=8;
Curu8=i;
return i;
}
//初始化快速反DCT
void jpeg_initfastidct(void)
{
short i;
iclp = iclip+512;
for (i= -512; i<512; i++)
iclp = (i<-256) ? -256: ((i>255) ? 255: i);
}
////////////////////////////////////////////////////////////////////////
void jpeg_idctrow(int * blk)
{
int x0, x1, x2, x3, x4, x5, x6, x7, x8;
//intcut
if (!((x1 = blk[4]<<11) | (x2 = blk[6]) | (x3 = blk[2]) |
(x4 = blk[1]) | (x5 = blk[7]) | (x6 = blk[5]) | (x7 = blk[3])))
{
blk[0]=blk[1]=blk[2]=blk[3]=blk[4]=blk[5]=blk[6]=blk[7]=blk[0]<<3;
return;
}
x0 = (blk[0]<<11) + 128; // for proper rounding in the fourth stage
//first stage
x8 = W7*(x4+x5);
x4 = x8 + (W1-W7)*x4;
x5 = x8 - (W1+W7)*x5;
x8 = W3*(x6+x7);
x6 = x8 - (W3-W5)*x6;
x7 = x8 - (W3+W5)*x7;
//second stage
x8 = x0 + x1;
x0 -= x1;
x1 = W6*(x3+x2);
x2 = x1 - (W2+W6)*x2;
x3 = x1 + (W2-W6)*x3;
x1 = x4 + x6;
x4 -= x6;
x6 = x5 + x7;
x5 -= x7;
//third stage
x7 = x8 + x3;
x8 -= x3;
x3 = x0 + x2;
x0 -= x2;
x2 = (181*(x4+x5)+128)>>8;
x4 = (181*(x4-x5)+128)>>8;
//fourth stage
blk[0] = (x7+x1)>>8;
blk[1] = (x3+x2)>>8;
blk[2] = (x0+x4)>>8;
blk[3] = (x8+x6)>>8;
blk[4] = (x8-x6)>>8;
blk[5] = (x0-x4)>>8;
blk[6] = (x3-x2)>>8;
blk[7] = (x7-x1)>>8;
}
//////////////////////////////////////////////////////////////////////////////
void jpeg_idctcol(int * blk)
{
int x0, x1, x2, x3, x4, x5, x6, x7, x8;
//intcut
if (!((x1 = (blk[8*4]<<8)) | (x2 = blk[8*6]) | (x3 = blk[8*2]) |
(x4 = blk[8*1]) | (x5 = blk[8*7]) | (x6 = blk[8*5]) | (x7 = blk[8*3])))
{
blk[8*0]=blk[8*1]=blk[8*2]=blk[8*3]=blk[8*4]=blk[8*5]
=blk[8*6]=blk[8*7]=iclp[(blk[8*0]+32)>>6];
return;
}
x0 = (blk[8*0]<<8) + 8192;
//first stage
x8 = W7*(x4+x5) + 4;
x4 = (x8+(W1-W7)*x4)>>3;
x5 = (x8-(W1+W7)*x5)>>3;
x8 = W3*(x6+x7) + 4;
x6 = (x8-(W3-W5)*x6)>>3;
x7 = (x8-(W3+W5)*x7)>>3;
//second stage
x8 = x0 + x1;
x0 -= x1;
x1 = W6*(x3+x2) + 4;
x2 = (x1-(W2+W6)*x2)>>3;
x3 = (x1+(W2-W6)*x3)>>3;
x1 = x4 + x6;
x4 -= x6;
x6 = x5 + x7;
x5 -= x7;
//third stage
x7 = x8 + x3;
x8 -= x3;
x3 = x0 + x2;
x0 -= x2;
x2 = (181*(x4+x5)+128)>>8;
x4 = (181*(x4-x5)+128)>>8;
//fourth stage
blk[8*0] = iclp[(x7+x1)>>14];
blk[8*1] = iclp[(x3+x2)>>14];
blk[8*2] = iclp[(x0+x4)>>14];
blk[8*3] = iclp[(x8+x6)>>14];
blk[8*4] = iclp[(x8-x6)>>14];
blk[8*5] = iclp[(x0-x4)>>14];
blk[8*6] = iclp[(x3-x2)>>14];
blk[8*7] = iclp[(x7-x1)>>14];
}
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