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  • vepro_hoffmannJuly 1, 2009 7:32 AM PDT   
    JPEG lossless encoding problem
    Hello,

    I'm currently running into problems while encoding some 16bit grayscale pictures to JPEG lossless using code from the JPEGView exampe.
    My code is working for most of the pictures but some just abort with JPEG_ERR_INTERNAL when returning from EncodeHuffmanMCURowLS.

    Picture information:
    witdh = 2320
    height = -2920
    bits per pixel  = 16 bit
    number of planes = 1

    Do you have any idea what is happening here? I think that every value should be valid as source pixel when encoding JPEG lossless.
    I've attached the uncompressed pixeldata and a screenshot of the image.
     Attachments 
    example.png
    uncompressed.zip

    Gennady Fedorov (Intel)July 3, 2009 7:51 AM PDT
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    		 #1
    Re: JPEG lossless encoding problem
    What IPP and ipp-sample versions you are using?
    ipp_sample ( look at support.txt file you can find ther smth. like Package ID: w_ipp-samples_p_6.1.0.038)
    --Gennady


    vepro_hoffmannJuly 6, 2009 12:20 AM PDT
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    		 #2 Reply To #1
    Re: JPEG lossless encoding problem
    What IPP and ipp-sample versions you are using?
    ipp_sample ( look at support.txt file you can find ther smth. like Package ID: w_ipp-samples_p_6.1.0.038)
    --Gennady


    I was using IPP5.3 Update 4 and updated my code to w_ipp-uic_p_6.0.0.130 and w_ipp_ia32_p_6.0.2.074.
    The problem stayed the same with the newer version.



    vepro_hoffmannJuly 13, 2009 2:05 AM PDT
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    		 #3 Reply To #2
    Re: JPEG lossless encoding problem
    Any news? I don't think that IPP6.1 would fix this issue.
    I can trace the problem into the UIC code right to the ippiEncodeHuffman function. The input seems valid to me.. and as I said before I can't think of any invalid input for huffman encoding in general.


    sryadnoJuly 14, 2009 12:41 AM PDT
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    		 #4 Reply To #3
    Re: JPEG lossless encoding problem
    Quoting - vepro_hoffmann
    Any news? I don't think that IPP6.1 would fix this issue.
    I can trace the problem into the UIC code right to the ippiEncodeHuffman function. The input seems valid to me.. and as I said before I can't think of any invalid input for huffman encoding in general.

    Hi, it seems some errors in our UIC jpeg codec in LOSSLESS mode. Try to do next fixes:

    1) In uic_jpeg_enc.h file change
    int GetPredictor(void) { return m_pntTransform; } to       int GetPredictor(void) { return m_predictor; }

    2) in jpegenc.cpp change

    buflen = (m_jpeg_mode == JPEG_LOSSLESS) ? IPP_MAX(ENC_DEFAULT_BUFLEN,m_numxMCU * m_jpeg_ncomp * 2) :     ENC_DEFAULT_BUFLEN;

    to


    buflen = (m_jpeg_mode == JPEG_LOSSLESS) ? IPP_MAX(ENC_DEFAULT_BUFLEN,m_numxMCU * m_jpeg_ncomp * 2 * 2) : ENC_DEFAULT_BUFLEN;





    vepro_hoffmannJuly 15, 2009 5:09 AM PDT
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    		 #5 Reply To #4
    Re: JPEG lossless encoding problem
    The second change did it. The buffersize was too small and that's why the encoding failed.
    It's also the same problem as in IPP5.3 Update 4.

    Thank you very much sryadno!


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