📄 jpeg.c
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#include "jpeg.h"
#include "uart.h"
#include "tft.h"
unsigned long xdata ImgWidth=0,ImgHeight=0;
unsigned long xdata counter=0;
//在JPEG函数里面用到的变量
long xdata SampRate_Y_H,SampRate_Y_V;
long xdata SampRate_U_H,SampRate_U_V;
long xdata SampRate_V_H,SampRate_V_V;
long xdata H_YtoU,V_YtoU,H_YtoV,V_YtoV;
long xdata Y_in_MCU,U_in_MCU,V_in_MCU;
unsigned char *lpJpegBuf;
unsigned char *lp;
long xdata qt_table[3][64];
long xdata comp_num;
unsigned char xdata comp_index[3];
unsigned char xdata YDcIndex,YAcIndex,UVDcIndex,UVAcIndex;
unsigned char xdata HufTabIndex;
long *YQtTable,*UQtTable,*VQtTable;
unsigned char xdata And[9]={0,1,3,7,0xf,0x1f,0x3f,0x7f,0xff};
long xdata code_pos_table[4][16],code_len_table[4][16];
unsigned long xdata code_value_table[4][256];
unsigned long xdata huf_max_value[4][16],huf_min_value[4][16];
long xdata BitPos,CurByte;
long xdata rrun,vvalue;
long xdata MCUBuffer[640];
long xdata QtZzMCUBuffer[640];
long xdata BlockBuffer[64];
long xdata ycoef,ucoef,vcoef;
unsigned char xdata longervalFlag;
long xdata longerval;
long xdata Y[256],U[256],V[256];
unsigned char data sizei,sizej;
long xdata restart;
unsigned long xdata iclip[1024];
unsigned long xdata *iclp;
//开始显示的坐标值
long xdata CurX=0;
long xdata CurY=0;
long code 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},
{9,11,18,24,37,40,44,53},
{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}
};
//读取JPEG代码，并解码
unsigned char LoadJpegFile (unsigned char *JpegFileName)
{
unsigned char *hJpegBuf;
long xdata funcret;
hJpegBuf=JpegFileName;//JPEG文件头
lpJpegBuf=(unsigned char*)hJpegBuf;//转换为变量指针
InitTable();
if((funcret=InitTag())!=FUNC_OK)//初始化表头不成功
{
//showerror(funcret);//错误信息显示
return FALSE;
}
if((SampRate_Y_H==0)||(SampRate_Y_V==0))
{
return FALSE ;
}
funcret=Decode();
if(funcret==FUNC_OK)//解码成功
{
return TRUE;
}
else
{
return FALSE;
}
}
////////////////////////////////////////////////////////////////////////////////
long InitTag()
{
unsigned char xdata finish=FALSE;
unsigned char xdata id;
long xdata i,j,k;
long xdata huftab1,huftab2;
long xdata huftabindex;
unsigned char xdata hf_table_index;
unsigned char xdata qt_table_index;
unsigned char xdata comnum;
unsigned char *lptemp;
long xdata colorount;
unsigned long data temp1,temp2;
unsigned long idata llength;
lp=lpJpegBuf+2;//跳过两个字节SOI(0xFF，0xD8 Start of Image)
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
switch (id)
{
case M_APP0: //JFIF APP0 segment marker (0xE0)
temp1=*(lp+1);temp2=*lp;
llength=MAKEWORD(temp1,temp2);
lp+=llength;
break;
case M_DQT: //定义量化表(0xFF,0xDB)
llength=MAKEWORD(*(lp+1),*lp);//(量化表长度)
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)
if(llength<80) //精度为 8 bit
{
for(i=0;i<64;i++)
qt_table[qt_table_index][i]=(long)*(lptemp++);
}
else //精度为 16 bit
{
for(i=0;i<64;i++)qt_table[qt_table_index][i]=(long)*(lptemp++);
qt_table_index=(*(lptemp++))&0x0f;
for(i=0;i<64;i++)qt_table[qt_table_index][i]=(long)*(lptemp++);
}
lp+=llength; //跳过量化表
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
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
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 byte), 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;
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=(long *)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=(long *)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=(long *)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=(long *)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=(long *)qt_table[*(lp+10)];
comp_index[2]=*(lp+8);
SampRate_V_H=1;
SampRate_V_V=1;
VQtTable=(long *)qt_table[*(lp+10)];
}
lp+=llength;
break;
case M_DHT: //定义 Huffman Table(0xFF,0xC4)
llength=MAKEWORD(*(lp+1),*lp);//长度 (高字节, 低字节)
if (llength<0xd0) // Huffman Table信息 (1 byte)
{
huftab1=(long)(*(lp+2))>>4; //huftab1=0,1(HT 类型,0 = DC 1 = AC)
huftab2=(long)(*(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;
for (i=0; i<16; i++) //16 bytes: 长度是 1..16 代码的符号数
code_len_table[huftabindex][i]=(long)(*(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][i]!=0)
{
k=0;
while(k<code_len_table[huftabindex][i])
{
code_value_table[huftabindex][k+j]=(long)(*(lptemp++));
k++;
}
j+=k;
}
}
i=0;
while (code_len_table[huftabindex][i]==0)i++;
for (j=0;j<i;j++)
{
huf_min_value[huftabindex][j]=0;
huf_max_value[huftabindex][j]=0;
}
huf_min_value[huftabindex][i]=0;
huf_max_value[huftabindex][i]=code_len_table[huftabindex][i]-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;
} //if
else
{
hf_table_index=*(lp+2);
lp+=2;
while (hf_table_index!=0xff)
{
huftab1=(long)hf_table_index>>4; //huftab1=0,1
huftab2=(long)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][i]=(long)(*(lptemp++));
colorount+=code_len_table[huftabindex][i];
}
colorount+=17;
j=0;
for (i=0; i<16; i++)
{
if(code_len_table[huftabindex][i]!=0)
{
k=0;
while(k<code_len_table[huftabindex][i])
{
code_value_table[huftabindex][k+j]=(long)(*(lptemp++));
k++;
}
j+=k;
}
}
i=0;
while (code_len_table[huftabindex][i]==0)i++;
for (j=0;j<i;j++)
{
huf_min_value[huftabindex][j]=0;
huf_max_value[huftabindex][j]=0;
}
huf_min_value[huftabindex][i]=0;
huf_max_value[huftabindex][i]=code_len_table[huftabindex][i]-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;
hf_table_index=*lp;
} //while
} //else
break;
case M_DRI:
llength=MAKEWORD(*(lp+1),*lp);
restart=MAKEWORD(*(lp+3),*(lp+2));
lp+=llength;
break;
case M_SOS:
llength=MAKEWORD(*(lp+1),*lp);
comnum=*(lp+2);
if(comnum!=comp_num)
return FUNC_FORMAT_ERROR;
lptemp=lp+3;
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;
}
lp+=llength;
finish=TRUE;
break;
case M_EOI://图片结束
return FUNC_FORMAT_ERROR;
break;
default:
if ((id&0xf0)!=0xd0)
{
llength=MAKEWORD(*(lp+1),*lp);
lp+=llength;
}
else lp+=2;
break;
} //switch
} //while
return FUNC_OK;
}
//初始化量化表，全部清零
void InitTable()
{
long xdata i,j;
sizei=sizej=0;
ImgWidth=ImgHeight=0;
rrun=vvalue=0;
BitPos=0;
CurByte=0;
longervalFlag=FALSE;
restart=0;
for(i=0;i<3;i++) //量化表
for(j=0;j<64;j++)
qt_table[i][j]=0;
comp_num=0;
HufTabIndex=0;
for(i=0;i<3;i++)
comp_index[i]=0;
for(i=0;i<4;i++)
for(j=0;j<16;j++){
code_len_table[i][j]=0;
code_pos_table[i][j]=0;
huf_max_value[i][j]=0;
huf_min_value[i][j]=0;
}
for(i=0;i<4;i++)
for(j=0;j<256;j++)
code_value_table[i][j]=0;
for(i=0;i<10*64;i++){
MCUBuffer[i]=0;
QtZzMCUBuffer[i]=0;
}
for(i=0;i<64;i++){
Y[i]=0;
U[i]=0;
V[i]=0;
BlockBuffer[i]=0;
}
ycoef=ucoef=vcoef=0;
}
//调用顺序: Initialize_Fast_IDCT() :初始化
// DecodeMCUBlock() Huffman Decode
// IQtIZzMCUComponent() 反量化、反DCT
// GetYUV() Get Y U V
// StoreBuffer() YUV to RGB
long Decode()
{
long xdata 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;
Initialize_Fast_IDCT();
while((funcret=DecodeMCUBlock())==FUNC_OK) //After Call DecodeMCUBUBlock()
{
longerval++; //The Digital has been Huffman Decoded and
if((restart)&&(longerval % restart==0))//be stored in MCUBuffer(YDU,YDU,YDU,YDU
longervalFlag=TRUE; // UDU,VDU) Every DU := 8*8
else
longervalFlag=FALSE;
IQtIZzMCUComponent(0); //反量化 and IDCT The Data in QtZzMCUBuffer
IQtIZzMCUComponent(1);
IQtIZzMCUComponent(2);
GetYUV(0); //得到Y cR cB
GetYUV(1);
GetYUV(2);
StoreBuffer(); //To RGB
sizej+=SampRate_Y_H*8;
if(sizej>=ImgWidth)
{
sizej=0;
sizei+=SampRate_Y_V*8;
}
if ((sizej==0)&&(sizei>=ImgHeight))break;
}
return funcret;
}
// 入口 QtZzMCUBuffer 出口 Y[] U[] V[]
//得到YUV色彩空间
void GetYUV(long flag)
{
long xdata H,VV;
long xdata i,j,k,h;
long *buf;
long *pQtZzMCU;
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 StoreBuffer()
{
long xdata i,j;
unsigned int color;
unsigned char xdata R,G,B;
long xdata y,u,v,rr,gg,bb;
int data counter=0;
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