Modifying exif information of JPEG-Exif encoded image

[umesh.roy]

I want to modify or add exif information into a image file which has already Exif information. We are able to modify exif information if we decode and write exif information. But we want to write exif information to a jpeg-exif encoded file using encoder only. Means we dont want to decode it.

We have used Texifutilitywriter , Mexifmetadata and CJpegExifencoder and CJpegExifdecoder classes. We want to use only Symbian class for this task or UIQ classes. PLease give me a pointer.

[symbianyucca]

Have you consided on searching ?

Just write Exif into the search box and you'll find plenty of discussions on this topic, as well as a link to a wiki example which I did couple of months ago.

[jitinarora]

Hello Umesh,
It can be done using only Symbian classes. You need to use only Texifwriterutility,Mexifmetadata and CJpegExifencoder classes to do this job.
Also you need to check what tags you want to add.
For example if you want to modify/add a tag named "Make".
Then call:
SetMake(HBufC8 *aMake); using TExifWriterUtility instance.
It will set the "Make" tag with the value you passed if tag is already there.
or
It will create a new tag "Make" and will initialise it with the value you pass.

Byt suppose you want to add a tag for which there is no direct API of class CExifWriterUtility, then you need to use APIs of MEXifMetaData class and pass the appropriate tag id for the tag you want to create. These tag id are defined in standard pdfs.

[symbianyucca]

The actual GPS-location tag writing APIs are actually non-public, but if you find the example from the Wiki, you could check how to make it with public APIs as well.

[umesh.roy]

Thanks for Reply. We have uses Exif Decoder to decode Exif Encoded Jpeg Image and tried to read and write , In this case read is success but writing is not happening into the file and there is no error or panic while writing. decoder is initialise with FileNewL function of Exif Decoder.
Other way we have uses Exif Decoder to decode Exif Encoded Jpeg Image and tried to read and write , In this case while initialising the decoder we left with " Not File Found" . Here i have used DataNewL() of exif decoder.

Please suggest what could be the mistake ?