Jpeg decoder cannot read image header

[Gregory_Begelman]

Hello,

I use the UIC JPEG decoder to decode images. The method ReadHeader fails on the attached image. Can this be a bug in UIC?

Thank you.

[Thomas_Jensen1]

I tested your jpeg using the latest IPP 7.4 Picnic sample app, and it fails loading it.
Windows 7 and LeadTools 16.5 can open it though. It appears to be an image saved by Photoshop on an Apple computer. It is probably corrupt in some way, and UIC cannot recover from the missing/bad data.

[Gregory_Begelman]

Other libraries successfully decode this image (like libjpeg-turbo). I suppose UIC should be able to decode it too.

[Vladimir_Dudnik]

Hello,

we have tested this image with UIC JPEG decoder and can confirm that there is a bug in UIC implementation. We are working on providing the fix for this issue. I'll update you once it is ready.
Note, the issue affects UIC sample code only, no changes in IPP libraries are needed.

Regards,
Vladimir

[Sergey_Ryadno]

hi,

i think i found the reason for this problem. To resolve it in file bitstreamin.cpp function CheckByte() need some modification. Try this solution and write here your results.

[bash]JERRCODE CBitStreamInput::CheckByte(int pos, int* byte)
{
  JERRCODE jerr;

  if(m_currPos + pos >= m_DataLen)
  {
    //jerr = Seek(pos);
    jerr = FillBuffer();
    if(JPEG_OK != jerr)
      return jerr;

    //*byte = m_pData[0];
    *byte = m_pData[pos];
  }
  else
    *byte = m_pData[m_currPos + pos];

  return JPEG_OK;
} // CBitStreamInput::CheckByte()[/bash]

[Thomas_Jensen1]

I can confirm that with this fix, the image in question can be decoded successfully.