JPEG encoder question

[axu]

I've tried both the new IPP-based IJL (ijl2.0) and the CJPEGEncoder class.

Interestingly I've found that the jpeg file size is much larger when you do a save in the jpegviewer based on CJPEGEncoder class. For example, I loaded a 169,514 bytes jpeg file. Once I clicked on the disk icon in the toolbar, the same filebecame 3,198,768 bytes. Something is not right. The jpgview program based on JIL-IPP does not have the same problem.

That issue aside, has anybody done any performance evaluation of the twoversions of encoder? From one of the earilier posts by Vladimir, it seems that Intel tends to support thec++ encoder and will drop C-based codec. Can somebody please confirm this?

-Anqing

Message Edited by axu@amicas.com on 04-29-2005 07:04 AM

[Vladimir_Dudnik]

Hi Anqing,

There was typo in JPGViewDoc.cpp file, actually it is very easy to fix:

you need to insert line in bold to the CJPGViewDoc::SaveAsJPEG() function (near to the end of function)

Code:

  jpeg.Open(lpszPathName,CFile::modeCreate|CFile::modeWrite|CFile::typeBinary);

  JPEGSize = encoder.m_dst.currPos;

  jpeg.Write(pJPEG,JPEGSize);

Regarding your next question, JPEG codec from JPEGView sample should be faster than IJL-IPP codec. On decoder side it even supports parallel decoding on multi-processor or multi-core systems whileas IJL-IPP do not have such support. We also have a plan to extend support of parallel processing on encoder side but not in the neareast release. I can confirm, we do not have plans to continue support of IJL-IPP sample.

BTW, we very interested in your valuable feedback on usability, interface, performance of our samples, so please share with us any issues you found or any suggestions you have. It will helps us to contnue improving of libraries and codecs.

Thanks,

Vladimir

[support2]

Jpeg support status:

Intel provides IJL 2.0 and inline codec in JpegView.

Intel doesn't provide anymore IJL1.5 library

IJG provides complete source code and Intel provides IPP integration to IJG

HP-Digital Imaging Group provides complete source code (FlashPix DSK)

Windows Codec are available throught VCM API (vfw) or DirectX

.... these are at least the various solutions I've tried and I'm using.

For speed the best solution is inline codec from Intel and then IJL20

For custom-specific usage the best solution is IJG and HP-DIG

Test done with P4 3ghz HT technology : free-running from camera BW/Color

Hope this can help,

SRSR