W3C home > Mailing lists > Public > xmlschema-dev@w3.org > September 2005

Re: Image information in XML

From: Pete Cordell <petexmldev@tech-know-ware.com>
Date: Thu, 29 Sep 2005 08:44:32 +0100
Message-ID: <002701c5c4c9$a70c02e0$a300a8c0@RW>
To: "Shashikala Shamarao" <shashikala_shamarao@yahoo.com>, <xmlschema-dev@w3.org>

Hi Shashi,

Yes.  You can compress the whole of the XML message with the image data 
contained in it.  Just looking at the JPEG part of a payload I did some 
quick tests and it seems that compressing would compensate for the base64 
expansion:

JPEG file:     105,482 bytes (where , has its UK meaning)
JPEG -> ZIP file:     105,417 bytes (implies JPEG is working well!)
JPEG -> Base64 file:     144,346 bytes (includes some extra line feeds in 
addition to 4/3 expansion)
JPEG -> Base64 -> ZIP file:     109, 293 bytes

This does show that compressing can get back much of what you loose by 
Base64 encoding.

Regards,

Pete.
--
=============================================
Pete Cordell
Tech-Know-Ware Ltd
                         for XML to C++ data binding visit
                         http://www.tech-know-ware.com/lmx
                         (or http://www.xml2cpp.com)
=============================================

----- Original Message ----- 
From: "Shashikala Shamarao" <shashikala_shamarao@yahoo.com>
To: "Pete Cordell" <petexmldev@tech-know-ware.com>; <xmlschema-dev@w3.org>
Sent: Wednesday, September 28, 2005 10:56 PM
Subject: Re: Image information in XML


> Hi Pete,
>
> Thanks for the response. Is it possible to compress the data after it has 
> been encoded.
>
> Thanks,
> Shashi
>
> Pete Cordell <petexmldev@tech-know-ware.com> wrote:
>
> Hi Shashi,
>
> The normal approach is to base64 encode binary data
> (http://www.faqs.org/rfcs/rfc3548.html) (or hex encode). This does result
> in some data expansion though. Every 3 bytes will be turned into 4. I
> don't know of any other solution that would work with a standard XML 
> parser,
> although some multiple file / out of band technique may work.
>
> Pete.
> ----- Original Message ----- 
> From: "Shashikala Shamarao"
> To:
> Sent: Wednesday, September 28, 2005 12:06 AM
> Subject: Image information in XML
>
>
>> Hi,
>>
>> Currently I am stuck with a problem realted to image in XML.
>>
>> I want to know how can I send image information in XML like below.
>>
>> My XML response should look like:
>>
>>
>>
>>
>> contains binary data
>>
>>
>>
>> contains binary data
>>
>>
>>
>> contains binary data
>>
>>
>>
>>
>>
>> I looked at multipart MIME, these define a boundary at the begining say
>> "bounary1" and at the end of every content whose mime type is different,
>> boundary will be defined. What I am wondering is, is it possible to 
>> define
>> boundary for each element , so I can send the bit by bit
>> information to the parser instead of waiting for the whole document to be
>> created in memory and then sending it to parser?
>>
>> Any answers would be appreciated.
>>
>> Thanks in advance
>> Shashi
> --
> =============================================
> Pete Cordell
> Tech-Know-Ware Ltd
> for XML to C++ data binding visit
> http://www.tech-know-ware.com/lmx
> (or http://www.xml2cpp.com)
> =============================================
>
>
>
>
>
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Received on Thursday, 29 September 2005 07:44:49 GMT

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