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CHAPTER 2 LIBRARY SPECIFICATIONS
Table 2-23. Members of JPEGINFO Structure
Member
Type
Bytes
Explanation
ErrorState
long
4
Error status
FileSize
long
4
JPEG file size
Quality
char
1
Quantization factor
Sampling
char
1
Sampling ratio
Restart
ushort
2
Restart interval
Width
ushort
2
Horizontal size of image
Height
ushort
2
Vertical size of image
StartX
ushort
2
Processing start x coordinate (for assumed image)
StartY
ushort
2
Processing start y coordinate (for assumed image)
CurrentX
ushort
2
Current x coordinate (for assumed image)
CurrentY
ushort
2
Current y coordinate (for assumed image)
VRAM_Bptr
uchar*
4
VRAM first address
VRAM_W_Pixel
ushort
2
Number of pixels in horizontal direction of assumed image
VRAM_H_Pixel
ushort
2
Number of pixels in vertical direction of assumed image
VRAM_Line_Byte
short
2
Number of bytes equivalent to VRAM address difference of one pixel in
vertical direction
VRAM_Pixel_Byte
short
2
Number of bytes equivalent to VRAM address difference of one pixel in
horizontal direction
VRAM_Gap1_Byte
short
2
Number of bytes equivalent to VRAM address difference of YCb or RG
VRAM_Gap2_Byte
short
2
Number of bytes equivalent to VRAM address difference of YCr or RB
JPEG_Buff_Bptr
uchar*
4
First address of JPEG file storage buffer
JPEG_Buff_Eptr
uchar*
4
End address of JPEG file storage buffer
MCU_Buff_Bptr
short*
4
First address of MCU buffer
RGB_Buff_Bptr
short*
4
First address of RGB buffer
DQT_Y_Bptr
char*
4
First address of quantization table (for luminance component)
DQT_C_Bptr
char*
4
First address of quantization table (for chrominance component)
DHT_DC_Y_Bptr
char*
4
First address of Huffman table (for DC luminance component)
DHT_DC_C_Bptr
char*
4
First address of Huffman table (for DC chrominance component)
DHT_AC_Y_Bptr
char*
4
First address of Huffman table (for AC luminance component)
DHT_AC_C_Bptr
char*
4
First address of Huffman table (for AC chrominance component)
APP_Info_Bptr
APPINFO*
4
First address of APPINFO structure variable
Work1_Bptr
long*
4
First address of library work area 1
Work2_Bptr
long*
4
First address of library work area 2
Work3
char
36
Library work area 3
Remark
uchar: unsigned char, ushort: unsigned short