?? jpeg.c
字號:
//=============================================================
// 文件名稱： jpeg_decoder.c
// 功能描述: jpeg解碼程序
// 維護記錄: 2007-8-13 by liuxue created
// 2007.08.23 V1.0 by lijian <lijian@sunnorth.com.cn>
//=============================================================
#include "JPEG.h"
#include "MPEG4_Driver.h"
#include "BLNDMA.h"
//=============================================================
// 語法格式： unsigned char *find_marker(unsigned char * jpg_ptr);
// 實現功能： 找jpeg的marker
// 參數： jpg_ptr，指向jpeg數據的指針
// 返回值： marker
//=============================================================
static unsigned char *find_marker(unsigned char * jpg_ptr)
{
while(*jpg_ptr != 0xff)
{
jpg_ptr++;
}
return ++jpg_ptr; // 返回marker
}
//=============================================================
// 語法格式： unsigned int get_jpg_segment_length(unsigned char *jpg_ptr);
// 實現功能： 找當前marker欄的長度
// 參數： jpg_ptr，指向jpeg數據的指針
// 返回值： length，當前marker欄的長度，長度不包括marker，但包括length本身
//=============================================================
static unsigned int get_jpg_segment_length(unsigned char *jpg_ptr)
{
unsigned int length;
length = (*jpg_ptr << 8) + *(jpg_ptr + 1);
return length;
}
//=============================================================
// 語法格式： unsigned char *bypass_jpg_segment(unsigned char *jpg_ptr);
// 實現功能： 跳過當前marker欄數據
// 參數： jpg_ptr，指向jpeg數據的指針
// 返回值： jpr_ptr，指向下一個marker欄首
//=============================================================
static unsigned char *bypass_jpg_segment(unsigned char *jpg_ptr)
{
unsigned int length;
length = get_jpg_segment_length(jpg_ptr);
jpg_ptr = jpg_ptr + length;
return jpg_ptr;
}
//=============================================================
// 語法格式： void fill_quantize_sram(unsigned char *jpg_ptr);
// 實現功能： 向SPCE3200填充量化表
// 參數： jpg_ptr，指向jpeg數據的指針
// 返回值： 無
//=============================================================
static void fill_quantize_sram(unsigned char *jpg_ptr)
{
const unsigned int jpeg_natural_order[64] = {
0, 1, 8, 16, 9, 2, 3, 10,
17, 24, 32, 25, 18, 11, 4, 5,
12, 19, 26, 33, 40, 48, 41, 34,
27, 20, 13, 6, 7, 14, 21, 28,
35, 42, 49, 56, 57, 50, 43, 36,
29, 22, 15, 23, 30, 37, 44, 51,
58, 59, 52, 45, 38, 31, 39, 46,
53, 60, 61, 54, 47, 55, 62, 63
}; // Zig-Zag變換
unsigned int i;
unsigned int length, counter;
unsigned char qtable[64];
unsigned char *pointer;
unsigned int *ptr;
length = get_jpg_segment_length(jpg_ptr);
counter = 2;
pointer = jpg_ptr + 2;
*P_MPEG4_QTABLE_SRAM = C_MPEG4_QTABLESRAM_EN; // enable CPU access Q Sram
while(counter < length)
{
if((*pointer & 0x0f)== 0x00)
{
ptr = (unsigned int *)P_MPEG4_QTABLE1_START;// fill Y Q_table ，亮度
}
else
{
ptr = (unsigned int *)P_MPEG4_QTABLE2_START;// fill C Q_table chroma，色度
}
counter++;
pointer++;
for(i=0; i<64; i++)
{
counter++;
qtable[jpeg_natural_order[i]] = *pointer++;
}
for(i=0;i<64;i++) // Fill Q_Table_SRAM
{
*ptr++ = (unsigned int)qtable[i];
}
} // while(counter < length)
*P_MPEG4_QTABLE_SRAM = C_MPEG4_QTABLESRAM_DIS; // disable CPU access Q Sram
}
//=============================================================
// 語法格式： int set_jpg_mode(unsigned char *jpg_ptr);
// 實現功能： 向SPCE3200填充高度、寬度、FRAME_Buffer 寬度等信息
// 根據jpeg圖片數據，選擇YUV格式
// 參數： jpg_ptr，指向jpeg數據的指針
// 返回值： 1: 成功; 0: 失敗
//=============================================================
static int set_jpg_mode(unsigned char *jpg_ptr)
{
unsigned char *pointer;
unsigned char word;
unsigned int width;
pointer = jpg_ptr + 3;
word = *pointer++;
*P_MPEG4_DECHEIGHT_HIGH = (unsigned int)word; // 高度
word = *pointer++;
*P_MPEG4_DECHEIGHT_LOW = (unsigned int)word;
word = *pointer++;
*P_MPEG4_DECWIDTH_HIGH = (unsigned int)word; // 寬度
width = (unsigned int)word;
width = width << 8;
word = *pointer++;
*P_MPEG4_DECWIDTH_LOW = (unsigned int)word;
width = width + (unsigned int)word;
*P_MPEG4_FRAMEBUFFER_HSIZE = width; // FRAMEBUFFER_HSIZE
word = *pointer++;
pointer++; // skip 1 byte
if(word==0x01) // 單色 01
{
*P_MPEG4_YUV_SEL = 0x00000000; // 0 : {yuv420, yuv422}
// 1 : {yuv411, yuv444}
*P_MPEG4_MODE_CTRL1 = C_MPEG4_JPEG_DEC
| C_MPEG4_YUV422_MODE
| C_MPEG4_COLOR_MODE;
}
else // 彩色 03
{
word = *pointer;
switch(word) // 分量水平sampling比例
{
case 0x11: // yuv444
*P_MPEG4_YUV_SEL = 0x00000001;
*P_MPEG4_MODE_CTRL1 = C_MPEG4_JPEG_DEC
| C_MPEG4_YUV444_MODE;
break;
case 0x21: // yuv422
*P_MPEG4_YUV_SEL = 0x00000000;
*P_MPEG4_MODE_CTRL1 = C_MPEG4_JPEG_DEC
| C_MPEG4_YUV422_MODE;
break;
case 0x41: // yuv411
*P_MPEG4_YUV_SEL = 0x00000001;
*P_MPEG4_MODE_CTRL1 = C_MPEG4_JPEG_DEC
| C_MPEG4_YUV411_MODE;
break;
case 0x22: // yuv420
*P_MPEG4_YUV_SEL = 0x00000000;
*P_MPEG4_MODE_CTRL1 = C_MPEG4_JPEG_DEC
| C_MPEG4_YUV420_MODE;
*P_MPEG4_YUV_MODE = 0x30;
break;
case 0x12: // 不支持 單 垂直采樣2:1模式
return 0; // i can't decode this JPG file
} // end switch
} // end if
return 1;
} // end function
//=============================================================
// 語法格式： Get_Huffman_cs_cw(unsigned char *cs, unsigned int *cw, unsigned char *pointer);
// 實現功能： 獲得Huffman表
// 參數： *cs，huffman的VLC的相對開始；*cw，存儲huffman表；*pointer，指向jpeg數據
// 返回值： 無
//=============================================================
static void Get_Huffman_cs_cw(unsigned char *cs, unsigned int *cw, unsigned char *pointer)
{
unsigned char pcount[16];
unsigned int index;
unsigned int l_codeword = 0; // local_codeword
unsigned int last_valid;
unsigned int j;
for(j=0; j<16; j++)
{
pcount[j] = *pointer++;
}
for(j=15; j>=0; j--)
{
if(pcount[j])
break;
}
last_valid = j;
for(index=0; index<16; index++)
{
if(0 == index)
{
cs[0] = 0;
}
else if(1 == index)
{
cs[1] = pcount[0];
}
else
{
cs[index] = cs[index - 1] + pcount[index - 1];
} // end if(0 == index)
if(index == 0)
{
cw[index] = 0;
if(pcount[0] == 1)
l_codeword = 1;
else
l_codeword = 0;
}
else if(index <= last_valid)
{
if(0 == cs[index])
{
l_codeword = 0;
}
l_codeword = l_codeword << 1;
cw[index] = l_codeword;
l_codeword = l_codeword + pcount[index];
}
else
{
cw[index] = 0xffff;
} // end if(index == 0)
} // end for(index=0; index<16; index++)
}
//=============================================================
// 語法格式： void set_Huff_sram_mode(int Page);
// 實現功能： 向SPCE3200填充TSRAM，前4頁存儲亮度信息，后4頁存儲色度信息
// 參數： Page，選擇TSRAM的頁數
// 返回值： 無
//=============================================================
static void set_Huff_sram_mode(int Page)
{
if(Page == 0)
*P_MPEG4_TSRAM_CTRL = C_MPEG4_CPU_TSRAM
| C_MPEG4_TSRAM_PAGE0;
else if(Page == 1)
*P_MPEG4_TSRAM_CTRL = C_MPEG4_CPU_TSRAM
| C_MPEG4_TSRAM_PAGE1;
else if(Page == 2)
*P_MPEG4_TSRAM_CTRL = C_MPEG4_CPU_TSRAM
| C_MPEG4_TSRAM_PAGE2;
else if(Page == 3)
*P_MPEG4_TSRAM_CTRL = C_MPEG4_CPU_TSRAM
| C_MPEG4_TSRAM_PAGE3;
else if(Page == 4)
*P_MPEG4_TSRAM_CTRL = C_MPEG4_CPU_TSRAM
| C_MPEG4_TSRAM_PAGE4;
else if(Page == 5)
*P_MPEG4_TSRAM_CTRL = C_MPEG4_CPU_TSRAM
| C_MPEG4_TSRAM_PAGE5;
else if(Page == 6)
*P_MPEG4_TSRAM_CTRL = C_MPEG4_CPU_TSRAM
| C_MPEG4_TSRAM_PAGE6;
else if(Page == 7)
*P_MPEG4_TSRAM_CTRL = C_MPEG4_CPU_TSRAM
| C_MPEG4_TSRAM_PAGE7;
else
*P_MPEG4_TSRAM_CTRL = C_MPEG4_CPU_REG;
}
//=============================================================
// 語法格式： set_jpg_huffman_cw_reg(unsigned char htype, unsigned int *cw);
// 實現功能： 填充Huffman表
// 參數： htype，huffman表的類型；*cw，存儲的huffman表
// 返回值： 無
//=============================================================
static void set_jpg_huffman_cw_reg(unsigned char htype, unsigned int *cw)
{
unsigned int i;
unsigned int *pointer;
if(htype == 0x00)
pointer = (unsigned int *)P_MPEG4_HUFFMAN_START; // YDC huffman
else if(htype == 0x01)
pointer = (unsigned int *)P_MPEG4_CHROMDCCODE_START; // CDC huffman
else if(htype == 0x10)
pointer = (unsigned int *)P_MPEG4_LUMACHUFFMANTABLE_START; // YAC huffman
else if(htype == 0x11)
pointer = (unsigned int *)P_MPEG4_CHROMACHUFFMANTABLE_START; // CAC huffman
for(i=0; i<8; i++)
{
*pointer++ = cw[i];
}
for(i=8; i<16; i++)
{
*pointer++ = cw[i];
*pointer++ = cw[i] >> 8;
}
}
//=============================================================
// 語法格式： set_jpg_huffman_acs_reg(int chrominance, unsigned char *cs);
// 實現功能： 填充 AC Huffman VLC偏移
// 參數： chrominance，選擇亮度還是色度；*cs，VLC偏移
// 返回值： 無
//=============================================================
static void set_jpg_huffman_acs_reg(int chrominance, unsigned char *cs)
{
unsigned int i;
unsigned int *pointer;
if(chrominance == 0)
{
pointer = (unsigned int *)P_MPEG4_LUMACHUFFMANOFFSET_SA;
}
else
{
pointer = (unsigned int *)P_MPEG4_CHROMACHUFFMANOFFSET_SA;
}
for(i=0; i<16; i++)
{
*pointer++ = (unsigned int)cs[i];
}
}
//=============================================================
// 語法格式： set_jpg_huffman_acs_reg(int chrominance, unsigned char *cs);
// 實現功能： 填充 AC Huffman值
// 參數： chrominance，選擇亮度還是色度；*cv，AC huffman值
// 返回值： 無
//=============================================================
static void set_jpg_huffman_acv_sram(int chrominance, unsigned char *cv)
{
unsigned int Huffman_SRAM_Page;
unsigned int *pointer;
unsigned int j, i, k;
if(chrominance == 0)
Huffman_SRAM_Page = 0;
else
Huffman_SRAM_Page = 4;
for(j=0; j<4; j++)
{
set_Huff_sram_mode(Huffman_SRAM_Page);
pointer = (unsigned int *)P_MPEG4_LUMDCCODE_START;
k= j * 64;
for(i=0; i<64; i++)
{
*pointer++ = (unsigned int)cv[k++];
}
Huffman_SRAM_Page++;
}
set_Huff_sram_mode(8);
}
//=============================================================
// 語法格式： void set_jpg_huffman_dcs_reg(int chrominance, unsigned char *cs);
// 實現功能： 填充 DC Huffman VLC偏移
// 參數： chrominance，選擇亮度還是色度；*cs，VLC偏移
// 返回值： 無
//=============================================================
static void set_jpg_huffman_dcs_reg(int chrominance, unsigned char *cs)
{
?? 快捷鍵說明
復制代碼
Ctrl + C
搜索代碼
Ctrl + F
全屏模式
F11
切換主題
Ctrl + Shift + D
顯示快捷鍵
?
增大字號
Ctrl + =
減小字號
Ctrl + -