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Re: wave file as alt tag?

From: Peter Meijer <meijer@natlab.research.philips.com>
Date: Sun, 16 May 1999 18:11:50 +0200
Message-Id: <373EEE46.15B2A1DC@natlab.research.philips.com>
To: w3c-wai-ig@w3.org
George Kerscher wrote

> The .wav file is very large, but various compression techniques can reduce
> the size (mpeg, Realaudio) and these files could also be streamed.

Yes, that will certainly help. For instance, the earlier 88K .wav 
example file from


becomes just a 16K MP3 file in


Still, since the image information is transmitted to the browser
as a regular image anyway, and since the sounds were in this 
example automatically created by importing the image into the 
software from


one would in principle not need to send or stream any audio data.
So this is really different from the normal Alt tag, of which the 
content is independently defined and added by the website developer,
typically to describe the semantics of an image. One of the often-
cited problems with that is that the Alt tag may be missing, or 
inaccurate, or even misleading.

When the image itself can be used to create a unique identifiable
sound in a completely general way, like David proposed, there is 
no need for the website developer to make any changes to his or 
her website. The browser plus the envisioned add-on can do it, and
render both the image (in the browser window) and the sound (with 
the add-on, or the plug-in that David mentions). 

However, I acknowledge that some extra audio rendering parameters,
as well as descriptive information provided by the website developer 
can be highly useful too, just like the Alt tag remains very useful 
to specify the semantics of an image, even as a pop-up string for 
the sighted. For instance, with the usflag.wav example it would be
convenient for the user if there were some tag like a SONIFY="the 
beeps are the stars, the tones are the stripes" which can help with
the interpretation of the image sound - and assuming that the image
to sound mapping is standardized. Of course, as with the good old 
ALT tag, the optional "SONIFY" tag may also be missing, inaccurate, 
or misleading because it must be provided by the website developer.

Doing image sonification automatically at the client side saves 
a lot of web transmission bandwidth and website storage space, and, 
most importantly, the website developer need not do anything, except 
optionally add a "SONIFY" tag to help with the interpretation of 
the image sounds.

> a plug in would have to of course be developped that would
> automatically process and sonify the image.

A plug-in is a good idea, but it would still require the use of new
tags, I'd think? It would be better if browsers were adapted to 
have the regular IMG tag link up with an optional add-on for image 
sonification. To my knowledge one cannot achieve the same result
using the current plug-in technology, which is about extensions
to HTML rather than redirecting the processing of existing HTML?

Best wishes,

Peter Meijer

Soundscapes from The vOICe - Seeing with your Ears!
Received on Sunday, 16 May 1999 12:01:33 UTC

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