[whatwg] Introduction of media accessibility features

Fri Apr 16 00:54:12 PDT 2010

On Fri, Apr 16, 2010 at 5:03 PM, Anne van Kesteren <annevk at opera.com> wrote:
> On Fri, 16 Apr 2010 15:49:38 +0900, Silvia Pfeiffer
> <silviapfeiffer1 at gmail.com> wrote:
>>
>> On Fri, Apr 16, 2010 at 3:32 PM, Anne van Kesteren <annevk at opera.com>
>> wrote:
>>>
>>
>> I guess the problem is more with char sets.
>> For HTML pages and other Web content, there is typically information
>> inside the resource that tells you what character set the document is
>> written in. E.g. HTML pages have
>> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">.
>> Such functionality is not available for SRT, so it is impossible for a
>> browser to tell what charset to use to render the content in.
>
> It would simply always be UTF-8, much like text/cache-manifest and
> text/event-stream.

There are plenty of SRT files out there that are not UTF-8. We do not
control the writing of those files, so cannot prescribe the charset.

>> (3) TTML file: (no hyperlinks, no images - just for comparison)
>>
>> ---
>> <?xml version="1.0" encoding="utf-8"?>
>> <tt xml:lang="en_us" xmlns="http://www.w3.org/ns/ttml">
>>  <head>
>>    <styling>
>>      <style xml:id="left-align"
>>        tts:fontFamily="proportionalSansSerif"
>>        tts:textAlign="left"
>>      />
>>      <style xml:id="right-align"
>>        tts:fontFamily="monospaceSerif"
>>        tts:textAlign="right"
>>      />
>>      <style xml:id="speaker"
>>        tts:fontFamily="monospaceSerif"
>>        tts:textAlign="left"
>>        tts:fontWeight="bold"
>>      />
>>    </styling>
>>    <layout>
>>      <region xml:id="subtitleArea"
>>        tts:extent="560px 62px"
>>        tts:padding="5px 3px"
>>      />
>>    </layout>
>>  </head>
>>  <body region="subtitleArea">
>>    <div>
>>      <p style="left-align" begin="0.15s" end="0.17s 951ms">
>>        <div style="speaker">Proog:</div>
>>        <div tts:color="green">At the <span
>> tts:fontStyle="italic">left</span> we can see...</div>
>>      </p>
>>      <p style="right-align" begin="0.18s 166ms" end="0.20s 83ms">
>>        <div tts:color="green">At the right we can see the...</div>
>>      </p>
>>    </div>
>>  </body>
>> </tt>
>> ---
>
> That this sample file has namespace errors and is therefore not well-formed
> is part of the reason I think TTML is a very bad idea. (Besides giving a new
> meaning to a bunch of HTML-like elements.)

I made up that example to see how difficult it would be. I have
probably made many mistakes in the markup, so don't take my word for
it. I am by no means a TTML expert. It sure was an interesting
experiment though!

Cheers,
Silvia.