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Science Forum Index » Image Processing Forum » faster color jpeg decoder
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Message |
| richard |
 Posted: Tue Jan 09, 2007 4:55 pm |
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Guest
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Hi all,
just tried a color jpeg decoder source code got from public source,
sounds like too slow, running 1366*1080 color image with a big dark area,
take 300ms, I run a jpeg decoder in ready made decoder, only take 120ms,
wondering if some where I can find a faster source code ?
I am using this kind of code:
void decode_MCU_2x2(DWORD im_loc)
{
// Y
process_Huffman_data_unit(YDC_nr,YAC_nr,&DCY);
IDCT_transform(DCT_coeff,Y_1,YQ_nr);
process_Huffman_data_unit(YDC_nr,YAC_nr,&DCY);
IDCT_transform(DCT_coeff,Y_2,YQ_nr);
process_Huffman_data_unit(YDC_nr,YAC_nr,&DCY);
IDCT_transform(DCT_coeff,Y_3,YQ_nr);
process_Huffman_data_unit(YDC_nr,YAC_nr,&DCY);
IDCT_transform(DCT_coeff,Y_4,YQ_nr);
// Cb
process_Huffman_data_unit(CbDC_nr,CbAC_nr,&DCCb);
IDCT_transform(DCT_coeff,Cb,CbQ_nr);
// Cr
process_Huffman_data_unit(CrDC_nr,CrAC_nr,&DCCr);
IDCT_transform(DCT_coeff,Cr,CrQ_nr);
convert_8x8_YCbCr_to_RGB_tab(Y_1,Cb,Cr,tab_1,im_loc,X_image_bytes,im_buffer)
;
convert_8x8_YCbCr_to_RGB_tab(Y_2,Cb,Cr,tab_2,im_loc+32,X_image_bytes,im_buff
er);
convert_8x8_YCbCr_to_RGB_tab(Y_3,Cb,Cr,tab_3,im_loc+y_inc_value,X_image_byte
s,im_buffer);
convert_8x8_YCbCr_to_RGB_tab(Y_4,Cb,Cr,tab_4,im_loc+y_inc_value+32,X_image_b
ytes,im_buffer);
}
I thought it's standard thing, but how come the speed so big diff than the
other decoder ?
thanks |
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| Nishu |
| Posted: Wed Jan 10, 2007 5:49 am |
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Guest
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richard wrote:
Quote: I thought it's standard thing, but how come the speed so big diff than the
other decoder ?
The difference ought to be there. There are variety of fast-algorithms
for IDCT and vld. Look out for fast algorithm implementation of
algorithms; or on other hand, try to optimize your code. |
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