jpg resolution

jpg resolution

Postby reinaldocrespo » Fri Jul 06, 2007 6:25 pm

Hi.

I keep jpg images stored a dbf/fpt file pair. It works well. Just to give an example leading to my point; at a given customer site 350k jpg images are kept on an 80GB .fpt file.

I just noticed that at a more recent installation, 26k images occupy an .fpt file of 115GB. I'm suspecting that the resolution at which the jpgs were created was very high.

Using BlobExport() I can extract and re-create any single jpg image file from the .fpt. My question is: is there any way to change the resolution on an already existing jpg so that it creates a smaller jpg?

Thank you,



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Postby reinaldocrespo » Sat Jul 07, 2007 1:32 am

What I need to know is if there is a utility to convert a jpg to another jpg with less (different) resolution. Or if perhaps freeimage could be used for this purpose.


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Postby Rick Lipkin » Sat Jul 07, 2007 3:12 pm

I use Infranview ( free ) .. It is a viewer conversion ( re-sampling ) image program . .stand alone.

You can download it from here :

http://www.irfanview.com/

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Postby RAMESHBABU » Sun Jul 08, 2007 6:46 pm

Mr.Reinaldo

I am using BMP2JPG.EXE, a file which converts a BMP file to JPG file
with the require percentage of quality. The Syntax is :

LOCAL cExec := 'BMP2JPG.EXE'

WaitRun(cExec+' -q'+LTRIM(STR(::nJpgQuality,3,0))+' -c' + ;
cOutputFile+' -o -s',0)

Please check your inbox for 'BMP2JPG.EXE'

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Postby Euclides » Sun Jul 08, 2007 8:21 pm

Hi Reinaldo,
In IrfanView, on the "Save" or "Save as" dialog, below there is a "Show options checkbox".
When clicked, shows the "JPEG/GIF Save Options" dialog.
In the JPG group there is a "Save quality" scroll bar.
Around 55 to 60 saves with a good quality and a good compression (1/10).
HTH
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Postby RAMESHBABU » Mon Jul 09, 2007 2:21 am

You can have a look at "FastStone Image Viewer". It is free and having
lots of features.

http://www.FastStone.org

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Postby reinaldocrespo » Mon Jul 09, 2007 10:03 pm

Thank you very much for all the responses.

I'm going to try with IrfanView. It looks like it will do the job.

My plan is to use source code to extract all the images from the .fpt file creating a single .jpg for each image. Then use the IrfanView's batch convert option to convert each jpg to a lower resolution jpg in one single command.

In the meanwhile I changed my scanning routines to make sure scanning happens at a standarized resolution declared on an .ini file to avoid this **unnecesary** huge files from happening in the future.



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