JPEG comment data

Rodney Tamblyn rodneytamblyn at paradise.net.nz
Tue Sep 23 21:15:00 CDT 2003


Hi Dar,

Thanks for the response.

For those who are interested, here's some links I've found to the Exif  
specification, the first one is especially good.

http://www.ba.wakwak.com/~tsuruzoh/Computer/Digicams/exif-e.html
http://www.exif.org/specifications.html
http://nwalsh.com/java/jpegrdf/

http://www.runrev.com/revolution/developers/bugdatabase/ 
show_bug.cgi?id=693

~ Rodney

On Wednesday, September 24, 2003, at 04:55 AM, Dar Scott wrote:

>
> On Monday, September 22, 2003, at 05:34 AM, Rodney Tamblyn wrote:
>
>> Does anyone have an example code snippet of how to access COM  
>> (comment) or APP1 chunk information from JPEG images in Revolution?
>
> I have not broken up JPEG, but I have attacked other binary files in  
> Revolution.
>
> The file format seems to be defined for additional info, though there  
> might be some idiosyncrasies.  Process the file using binaryDecode.   
> One approach would be to make a function that takes an image and  
> returns, say, an array of values by name.  The name might be based on  
> that used in standards.  For fixed position fields, access functions  
> might work, but I have found that accessing data with variable length  
> fields is easier if the file is preprocessed to break out the  
> components.  The only problem is that arrays can currently be only one  
> layer deep and line and item lists are needed for the other levels.   
> In most cases that is just fine.  In other cases, data can be burst in  
> layers.
>
> Dar Scott
>
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>     http://www.swcp.com/dsc/
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--
Rodney Tamblyn
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Dunedin
New Zealand
+64 3 4778606
http://rodney.weblogs.com/




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